clk: vc5: Add support for IDT VersaClock 5P49V5923B

Message ID	20161228000045.4540-1-marek.vasut@gmail.com (mailing list archive)
State	Superseded
Delegated to:	Stephen Boyd
Headers	show Return-Path: <linux-clk-owner@kernel.org> From: Marek Vasut <marek.vasut@gmail.com> To: linux-clk@vger.kernel.org Cc: Marek Vasut <marek.vasut@gmail.com>, Michael Turquette <mturquette@baylibre.com>, Stephen Boyd <sboyd@codeaurora.org> Subject: [PATCH] clk: vc5: Add support for IDT VersaClock 5P49V5923B Date: Wed, 28 Dec 2016 01:00:45 +0100 Message-Id: <20161228000045.4540-1-marek.vasut@gmail.com> Sender: linux-clk-owner@vger.kernel.org Precedence: bulk

Marek Vasut Dec. 28, 2016, midnight UTC

Add driver for IDT VersaClock 5 5P49V5923B chip. This chip has two
clock inputs, XTAL or CLK, which are muxed into single PLL/VCO input.
The PLL feeds two fractional dividers. Each fractional divider feeds
output mux, which allows selecting between clock from the fractional
divider itself or from output mux on output N-1. In case of output
mux 0, the output N-1 is instead connected to the output from the mux
feeding the PLL.

The driver thus far supports only the 5P49V5923B, while it should be
easily extensible to the whole 5P49V59xx family of chips as they are
all pretty similar.

Signed-off-by: Marek Vasut <marek.vasut@gmail.com>
Cc: Michael Turquette <mturquette@baylibre.com>
Cc: Stephen Boyd <sboyd@codeaurora.org>
---
 .../devicetree/bindings/clock/idt,versaclock5.txt  |  41 ++
 drivers/clk/Kconfig                                |  10 +
 drivers/clk/Makefile                               |   1 +
 drivers/clk/clk-versaclock5.c                      | 696 +++++++++++++++++++++
 4 files changed, 748 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/clock/idt,versaclock5.txt
 create mode 100644 drivers/clk/clk-versaclock5.c

Geert Uytterhoeven Jan. 2, 2017, 1:46 p.m. UTC | #1

CC linux-renesas-soc, as this driver is used for a device on the
Renesas Salvator-X board.

On Wed, Dec 28, 2016 at 1:00 AM, Marek Vasut <marek.vasut@gmail.com> wrote:
> Add driver for IDT VersaClock 5 5P49V5923B chip. This chip has two
> clock inputs, XTAL or CLK, which are muxed into single PLL/VCO input.
> The PLL feeds two fractional dividers. Each fractional divider feeds
> output mux, which allows selecting between clock from the fractional
> divider itself or from output mux on output N-1. In case of output
> mux 0, the output N-1 is instead connected to the output from the mux
> feeding the PLL.
>
> The driver thus far supports only the 5P49V5923B, while it should be
> easily extensible to the whole 5P49V59xx family of chips as they are
> all pretty similar.
>
> Signed-off-by: Marek Vasut <marek.vasut@gmail.com>
> Cc: Michael Turquette <mturquette@baylibre.com>
> Cc: Stephen Boyd <sboyd@codeaurora.org>
> ---
>  .../devicetree/bindings/clock/idt,versaclock5.txt  |  41 ++
>  drivers/clk/Kconfig                                |  10 +
>  drivers/clk/Makefile                               |   1 +
>  drivers/clk/clk-versaclock5.c                      | 696 +++++++++++++++++++++
>  4 files changed, 748 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/clock/idt,versaclock5.txt
>  create mode 100644 drivers/clk/clk-versaclock5.c
>
> diff --git a/Documentation/devicetree/bindings/clock/idt,versaclock5.txt b/Documentation/devicetree/bindings/clock/idt,versaclock5.txt
> new file mode 100644
> index 0000000..cbe5bc8
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/clock/idt,versaclock5.txt
> @@ -0,0 +1,41 @@
> +Binding for IDT VersaClock5 programmable i2c clock generator.
> +
> +The IDT VersaClock5 are programmable i2c clock generators providing
> +from 3 to 12 output clocks.
> +
> +==I2C device node==
> +
> +Required properties:
> +- compatible:  shall be one of "idt,5p49v5923b".
> +- reg:         i2c device address, shall be 0x68 or 0x6a.
> +- #clock-cells:        from common clock binding; shall be set to 1.
> +- clocks:      from common clock binding; list of parent clock handles,
> +               shall be XTAL or CLKIN reference clock. Corresponding
> +               clock input names are "xin" and "clkin" respectively.
> +- #address-cells: shall be set to 1.
> +- #size-cells: shall be set to 0.
> +
> +==Example==
> +
> +/* 25MHz reference crystal */
> +ref25: ref25m {
> +       compatible = "fixed-clock";
> +       #clock-cells = <0>;
> +       clock-frequency = <25000000>;
> +};
> +
> +i2c-master-node {
> +
> +       /* IDT 5P49V5923B i2c clock generator */
> +       vc5: clock-generator@6a {
> +               compatible = "idt,5p49v5923b";
> +               reg = <0x6a>;
> +               #address-cells = <1>;
> +               #size-cells = <0>;
> +               #clock-cells = <1>;
> +
> +               /* Connect XIN input to 25MHz reference */
> +               clocks = <&ref25m>;
> +               clock-names = "xin";
> +       };
> +};
> diff --git a/drivers/clk/Kconfig b/drivers/clk/Kconfig
> index 6a8ac04..9160e67 100644
> --- a/drivers/clk/Kconfig
> +++ b/drivers/clk/Kconfig
> @@ -198,6 +198,16 @@ config COMMON_CLK_OXNAS
>         ---help---
>           Support for the OXNAS SoC Family clocks.
>
> +config COMMON_CLK_VC5
> +       tristate "Clock driver for IDT VersaClock5 devices"
> +       depends on I2C
> +       depends on OF
> +       select REGMAP_I2C
> +       help
> +       ---help---
> +         This driver supports the IDT VersaClock5 programmable clock
> +         generator.
> +
>  source "drivers/clk/bcm/Kconfig"
>  source "drivers/clk/hisilicon/Kconfig"
>  source "drivers/clk/mediatek/Kconfig"
> diff --git a/drivers/clk/Makefile b/drivers/clk/Makefile
> index 925081e..e0754d9 100644
> --- a/drivers/clk/Makefile
> +++ b/drivers/clk/Makefile
> @@ -46,6 +46,7 @@ obj-$(CONFIG_ARCH_TANGO)              += clk-tango4.o
>  obj-$(CONFIG_CLK_TWL6040)              += clk-twl6040.o
>  obj-$(CONFIG_ARCH_U300)                        += clk-u300.o
>  obj-$(CONFIG_ARCH_VT8500)              += clk-vt8500.o
> +obj-$(CONFIG_COMMON_CLK_VC5)           += clk-versaclock5.o
>  obj-$(CONFIG_COMMON_CLK_WM831X)                += clk-wm831x.o
>  obj-$(CONFIG_COMMON_CLK_XGENE)         += clk-xgene.o
>
> diff --git a/drivers/clk/clk-versaclock5.c b/drivers/clk/clk-versaclock5.c
> new file mode 100644
> index 0000000..286689d
> --- /dev/null
> +++ b/drivers/clk/clk-versaclock5.c
> @@ -0,0 +1,696 @@
> +/*
> + * Driver for IDT Versaclock 5
> + *
> + * Copyright (C) 2016 Marek Vasut <marek.vasut@gmail.com>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation; either version 2 of the License, or
> + * (at your option) any later version.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + */
> +
> +/*
> + * Possible optimizations:
> + * - Support other chips but 5P49V5923B
> + * - Use spread spectrum
> + * - Use integer divider in FOD if applicable
> + * - register OUT0_SEL_I2CB
> + */
> +
> +#include <linux/clk.h>
> +#include <linux/clk-provider.h>
> +#include <linux/delay.h>
> +#include <linux/i2c.h>
> +#include <linux/interrupt.h>
> +#include <linux/mod_devicetable.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/rational.h>
> +#include <linux/regmap.h>
> +#include <linux/slab.h>
> +
> +/* VersaClock5 registers */
> +#define VC5_OTP_CONTROL                                0x00
> +
> +/* Factory-reserved register block */
> +#define VC5_RSVD_DEVICE_ID                     0x01
> +#define VC5_RSVD_ADC_GAIN_7_0                  0x02
> +#define VC5_RSVD_ADC_GAIN_15_8                 0x03
> +#define VC5_RSVD_ADC_OFFSET_7_0                        0x04
> +#define VC5_RSVD_ADC_OFFSET_15_8               0x05
> +#define VC5_RSVD_TEMPY                         0x06
> +#define VC5_RSVD_OFFSET_TBIN                   0x07
> +#define VC5_RSVD_GAIN                          0x08
> +#define VC5_RSVD_TEST_NP                       0x09
> +#define VC5_RSVD_UNUSED                                0x0a
> +#define VC5_RSVD_BANDGAP_TRIM_UP               0x0b
> +#define VC5_RSVD_BANDGAP_TRIM_DN               0x0c
> +#define VC5_RSVD_CLK_R_12_CLK_AMP_4            0x0d
> +#define VC5_RSVD_CLK_R_34_CLK_AMP_4            0x0e
> +#define VC5_RSVD_CLK_AMP_123                   0x0f
> +
> +/* Configuration register block */
> +#define VC5_PRIM_SRC_SHDN                      0x10
> +#define VC5_PRIM_SRC_SHDN_EN_XTAL              BIT(7)
> +#define VC5_PRIM_SRC_SHDN_EN_CLKIN             BIT(6)
> +#define VC5_PRIM_SRC_SHDN_SP                   BIT(1)
> +#define VC5_PRIM_SRC_SHDN_EN_GBL_SHDN          BIT(0)
> +
> +#define VC5_VCO_BAND                           0x11
> +#define VC5_XTAL_X1_LOAD_CAP                   0x12
> +#define VC5_XTAL_X2_LOAD_CAP                   0x13
> +#define VC5_REF_DIVIDER                                0x15
> +#define VC5_REF_DIVIDER_SEL_PREDIV2            BIT(7)
> +#define VC5_REF_DIVIDER_REF_DIV(n)             ((n) & 0x3f)
> +
> +#define VC5_VCO_CTRL_AND_PREDIV                        0x16
> +#define VC5_VCO_CTRL_AND_PREDIV_BYPASS_PREDIV  BIT(7)
> +
> +#define VC5_FEEDBACK_INT_DIV                   0x17
> +#define VC5_FEEDBACK_INT_DIV_BITS              0x18
> +#define VC5_FEEDBACK_FRAC_DIV(n)               (0x19 + (n))
> +#define VC5_RC_CONTROL0                                0x1e
> +#define VC5_RC_CONTROL1                                0x1f
> +/* Register 0x20 is factory reserved */
> +
> +/* Output divider control for divider 1,2,3,4 */
> +#define VC5_OUT_DIV_CONTROL(idx)       (0x21 + ((idx) * 0x10))
> +#define VC5_OUT_DIV_CONTROL_RESET      BIT(7)
> +#define VC5_OUT_DIV_CONTROL_SELB_NORM  BIT(3)
> +#define VC5_OUT_DIV_CONTROL_SEL_EXT    BIT(2)
> +#define VC5_OUT_DIV_CONTROL_INT_MODE   BIT(1)
> +#define VC5_OUT_DIV_CONTROL_EN_FOD     BIT(0)
> +
> +#define VC5_OUT_DIV_FRAC(idx, n)       (0x22 + ((idx) * 0x10) + (n))
> +#define VC5_OUT_DIV_FRAC4_OD_SCEE      BIT(1)
> +
> +#define VC5_OUT_DIV_STEP_SPREAD(idx, n)        (0x26 + ((idx) * 0x10) + (n))
> +#define VC5_OUT_DIV_SPREAD_MOD(idx, n) (0x29 + ((idx) * 0x10) + (n))
> +#define VC5_OUT_DIV_SKEW_INT(idx, n)   (0x2b + ((idx) * 0x10) + (n))
> +#define VC5_OUT_DIV_INT(idx, n)                (0x2d + ((idx) * 0x10) + (n))
> +#define VC5_OUT_DIV_SKEW_FRAC(idx)     (0x2f + ((idx) * 0x10))
> +/* Register 0x30, 0x40, 0x50 is factory reserved */
> +
> +/* Clock control register for clock 1,2 */
> +#define VC5_CLK_OUTPUT_CFG(idx, n)     (0x60 + ((idx) * 0x2) + (n))
> +#define VC5_CLK_OUTPUT_CFG1_EN_CLKBUF  BIT(0)
> +
> +#define VC5_CLK_OE_SHDN                                0x68
> +#define VC5_CLK_OS_SHDN                                0x69
> +
> +/* PLL/VCO runs between 2.5 GHz and 3.0 GHz */
> +#define VC5_PLL_VCO_MIN                                2500000000
> +#define VC5_PLL_VCO_MAX                                3000000000
> +
> +struct vc5_driver_data;
> +
> +struct vc5_hw_data {
> +       struct clk_hw           hw;
> +       struct vc5_driver_data  *vc5;
> +       unsigned long           div_int;
> +       unsigned long           div_frc;
> +       unsigned char           num;
> +};
> +
> +struct vc5_driver_data {
> +       struct i2c_client       *client;
> +       struct regmap           *regmap;
> +
> +       struct clk              *pin_xin;
> +       const char              *pin_xin_name;
> +       struct clk_hw           clk_xin;
> +       struct clk              *pin_clkin;
> +       const char              *pin_clkin_name;
> +       struct clk_hw           clk_clkin;
> +       unsigned char           clk_mux_ins;
> +       struct clk_hw           clk_mux;
> +       struct vc5_hw_data      clk_pll;
> +       struct vc5_hw_data      clk_fod[2];
> +       struct vc5_hw_data      clk_out[3];
> +};
> +
> +static const char * const vc5_input_names[] = {
> +       "xin", "clkin"
> +};
> +
> +static const char * const vc5_pll_names[] = {
> +       "pll"
> +};
> +
> +static const char * const vc5_mux_names[] = {
> +       "mux"
> +};
> +
> +static const char * const vc5_fod_names[] = {
> +       "fod0", "fod1"
> +};
> +
> +static const char * const vc5_clk_out_names[] = {
> +       "out0_sel_i2cb", "out1", "out2"
> +};
> +
> +/*
> + * VersaClock5 i2c regmap
> + */
> +static bool vc5_regmap_is_writeable(struct device *dev, unsigned int reg)
> +{
> +       /* Factory reserved regs, make them read-only */
> +       if (reg >= 0 && reg <= 0xf)
> +               return false;
> +
> +       /* Factory reserved regs, make them read-only */
> +       if (reg == 0x14 || reg == 0x1c || reg == 0x1d)
> +               return false;
> +
> +       return true;
> +}
> +
> +static const struct regmap_config vc5_regmap_config = {
> +       .reg_bits = 8,
> +       .val_bits = 8,
> +       .cache_type = REGCACHE_RBTREE,
> +       .max_register = 0x69,
> +       .writeable_reg = vc5_regmap_is_writeable,
> +};
> +
> +/*
> + * VersaClock5 input multiplexer between XTAL and CLKIN divider
> + */
> +static unsigned char vc5_mux_get_parent(struct clk_hw *hw)
> +{
> +       struct vc5_driver_data *vc5 =
> +               container_of(hw, struct vc5_driver_data, clk_mux);
> +       const u8 mask = VC5_PRIM_SRC_SHDN_EN_XTAL | VC5_PRIM_SRC_SHDN_EN_CLKIN;
> +       unsigned int src;
> +
> +       regmap_read(vc5->regmap, VC5_PRIM_SRC_SHDN, &src);
> +       src &= mask;
> +
> +       if (src == VC5_PRIM_SRC_SHDN_EN_XTAL)
> +               return 0;
> +
> +       if (src == VC5_PRIM_SRC_SHDN_EN_CLKIN)
> +               return 1;
> +
> +       dev_warn(&vc5->client->dev,
> +                "Invalid clock input configuration (%02x)\n", src);
> +       return 0;
> +}
> +
> +static int vc5_mux_set_parent(struct clk_hw *hw, u8 index)
> +{
> +       struct vc5_driver_data *vc5 =
> +               container_of(hw, struct vc5_driver_data, clk_mux);
> +       const u8 mask = VC5_PRIM_SRC_SHDN_EN_XTAL | VC5_PRIM_SRC_SHDN_EN_CLKIN;
> +       u8 src;
> +
> +       if ((index > 1) || !vc5->clk_mux_ins)
> +               return -EINVAL;
> +
> +       if (vc5->clk_mux_ins == (BIT(0) | BIT(1))) {
> +               if (index == 0)
> +                       src = VC5_PRIM_SRC_SHDN_EN_XTAL;
> +               if (index == 1)
> +                       src = VC5_PRIM_SRC_SHDN_EN_CLKIN;
> +       } else {
> +               if (index != 0)
> +                       return -EINVAL;
> +
> +               if (vc5->clk_mux_ins == BIT(0))
> +                       src = VC5_PRIM_SRC_SHDN_EN_XTAL;
> +               if (vc5->clk_mux_ins == BIT(1))
> +                       src = VC5_PRIM_SRC_SHDN_EN_CLKIN;
> +       }
> +
> +       return regmap_update_bits(vc5->regmap, VC5_PRIM_SRC_SHDN, mask, src);
> +}
> +
> +static unsigned long vc5_mux_recalc_rate(struct clk_hw *hw,
> +                                        unsigned long parent_rate)
> +{
> +       struct vc5_driver_data *vc5 =
> +               container_of(hw, struct vc5_driver_data, clk_mux);
> +       unsigned long idiv;
> +       u8 div;
> +
> +       /* FIXME: Needs locking ? */
> +
> +       /* CLKIN within range of PLL input, feed directly to PLL. */
> +       if (parent_rate <= 50000000) {
> +               regmap_update_bits(vc5->regmap, VC5_VCO_CTRL_AND_PREDIV,
> +                                  VC5_VCO_CTRL_AND_PREDIV_BYPASS_PREDIV,
> +                                  VC5_VCO_CTRL_AND_PREDIV_BYPASS_PREDIV);
> +               regmap_update_bits(vc5->regmap, VC5_REF_DIVIDER, 0xff, 0x00);
> +               return parent_rate;
> +       }
> +
> +       idiv = DIV_ROUND_UP(parent_rate, 50000000);
> +       if (idiv > 127)
> +               return -EINVAL;
> +
> +       /* We have dedicated div-2 predivider. */
> +       if (idiv == 2)
> +               div = VC5_REF_DIVIDER_SEL_PREDIV2;
> +       else
> +               div = VC5_REF_DIVIDER_REF_DIV(idiv);
> +
> +       regmap_update_bits(vc5->regmap, VC5_REF_DIVIDER, 0xff, div);
> +       regmap_update_bits(vc5->regmap, VC5_VCO_CTRL_AND_PREDIV,
> +                          VC5_VCO_CTRL_AND_PREDIV_BYPASS_PREDIV, 0);
> +
> +       return parent_rate / idiv;
> +}
> +
> +static const struct clk_ops vc5_mux_ops = {
> +       .set_parent     = vc5_mux_set_parent,
> +       .get_parent     = vc5_mux_get_parent,
> +       .recalc_rate    = vc5_mux_recalc_rate,
> +};
> +
> +/*
> + * VersaClock5 PLL/VCO
> + */
> +static unsigned long vc5_pll_recalc_rate(struct clk_hw *hw,
> +                                        unsigned long parent_rate)
> +{
> +       struct vc5_hw_data *hwdata = container_of(hw, struct vc5_hw_data, hw);
> +       struct vc5_driver_data *vc5 = hwdata->vc5;
> +       u32 div_int, div_frc;
> +       u8 fb[5];
> +
> +       regmap_bulk_read(vc5->regmap, VC5_FEEDBACK_INT_DIV, fb, 5);
> +
> +       div_int = (fb[0] << 4) | (fb[1] >> 4);
> +       div_frc = (fb[2] << 16) | (fb[3] << 8) | fb[4];
> +
> +       /* The PLL divider has 12 integer bits and 24 fractional bits */
> +       return (parent_rate * div_int) + ((parent_rate * div_frc) >> 24);
> +}
> +
> +static long vc5_pll_round_rate(struct clk_hw *hw, unsigned long rate,
> +                              unsigned long *parent_rate)
> +{
> +       struct vc5_hw_data *hwdata = container_of(hw, struct vc5_hw_data, hw);
> +       unsigned long div_int;
> +       unsigned long long div_frc;
> +
> +       if (rate < VC5_PLL_VCO_MIN)
> +               rate = VC5_PLL_VCO_MIN;
> +       if (rate > VC5_PLL_VCO_MAX)
> +               rate = VC5_PLL_VCO_MAX;
> +
> +       /* Determine integer part, which is 12 bit wide */
> +       div_int = rate / *parent_rate;
> +       if (div_int > 0xfff)
> +               rate = *parent_rate * 0xfff;
> +
> +       /* Determine best fractional part, which is 24 bit wide */
> +       div_frc = rate % *parent_rate;
> +       div_frc *= BIT(24) - 1;
> +       do_div(div_frc, *parent_rate);
> +
> +       hwdata->div_int = div_int;
> +       hwdata->div_frc = (unsigned long)div_frc;
> +
> +       return (*parent_rate * div_int) + ((*parent_rate * div_frc) >> 24);
> +}
> +
> +static int vc5_pll_set_rate(struct clk_hw *hw, unsigned long rate,
> +                           unsigned long parent_rate)
> +{
> +       struct vc5_hw_data *hwdata = container_of(hw, struct vc5_hw_data, hw);
> +       struct vc5_driver_data *vc5 = hwdata->vc5;
> +       u8 fb[5];
> +
> +       fb[0] = hwdata->div_int >> 4;
> +       fb[1] = hwdata->div_int << 4;
> +       fb[2] = hwdata->div_frc >> 16;
> +       fb[3] = hwdata->div_frc >> 8;
> +       fb[4] = hwdata->div_frc;
> +
> +       return regmap_bulk_write(vc5->regmap, VC5_FEEDBACK_INT_DIV, fb, 5);
> +}
> +
> +static const struct clk_ops vc5_pll_ops = {
> +       .recalc_rate    = vc5_pll_recalc_rate,
> +       .round_rate     = vc5_pll_round_rate,
> +       .set_rate       = vc5_pll_set_rate,
> +};
> +
> +static unsigned long vc5_fod_recalc_rate(struct clk_hw *hw,
> +                                        unsigned long parent_rate)
> +{
> +       struct vc5_hw_data *hwdata = container_of(hw, struct vc5_hw_data, hw);
> +       struct vc5_driver_data *vc5 = hwdata->vc5;
> +       /* VCO frequency is divided by two before entering FOD */
> +       u64 f_in = parent_rate / 2;
> +       u64 div_int, div_frc;
> +       u8 od_int[2];
> +       u8 od_frc[4];
> +
> +       regmap_bulk_read(vc5->regmap, VC5_OUT_DIV_INT(hwdata->num, 0),
> +                        od_int, 2);
> +       regmap_bulk_read(vc5->regmap, VC5_OUT_DIV_FRAC(hwdata->num, 0),
> +                        od_frc, 4);
> +
> +       div_int = (od_int[0] << 4) | (od_int[1] >> 4);
> +       div_frc = (od_frc[0] << 22) | (od_frc[1] << 14) |
> +                 (od_frc[2] << 6) | (od_frc[3] >> 2);
> +
> +       /* The PLL divider has 12 integer bits and 30 fractional bits */
> +       return div64_u64(f_in << 30ULL, (div_int << 30ULL) + div_frc);
> +}
> +
> +static long vc5_fod_round_rate(struct clk_hw *hw, unsigned long rate,
> +                              unsigned long *parent_rate)
> +{
> +       struct vc5_hw_data *hwdata = container_of(hw, struct vc5_hw_data, hw);
> +       /* VCO frequency is divided by two before entering FOD */
> +       unsigned long long f_in = *parent_rate / 2;
> +       unsigned long div_int;
> +       unsigned long long div_frc;
> +
> +       /* Determine integer part, which is 12 bit wide */
> +       div_int = f_in / rate;
> +       /*
> +        * WARNING: The clock chip does not output signal if the integer part
> +        *          of the divider is 0xfff and fractional part is non-zero.
> +        *          Clamp the divider at 0xffe to keep the code simple.
> +        */
> +       if (div_int > 0xffe) {
> +               div_int = 0xffe;
> +               rate = f_in / div_int;
> +       }
> +
> +       /* Determine best fractional part, which is 30 bit wide */
> +       div_frc = f_in % rate;
> +       div_frc *= BIT(30) - 1;
> +       do_div(div_frc, rate);
> +
> +       hwdata->div_int = div_int;
> +       hwdata->div_frc = (unsigned long)div_frc;
> +
> +       return div64_u64(f_in << 30ULL, (div_int << 30ULL) + div_frc);
> +}
> +
> +static int vc5_fod_set_rate(struct clk_hw *hw, unsigned long rate,
> +                           unsigned long parent_rate)
> +{
> +       struct vc5_hw_data *hwdata = container_of(hw, struct vc5_hw_data, hw);
> +       struct vc5_driver_data *vc5 = hwdata->vc5;
> +       u8 od_int[2];
> +       u8 od_frc[4];
> +
> +       od_int[0] = hwdata->div_int >> 4;
> +       od_int[1] = hwdata->div_int << 4;
> +       od_frc[0] = hwdata->div_frc >> 22;
> +       od_frc[1] = hwdata->div_frc >> 14;
> +       od_frc[2] = hwdata->div_frc >> 6;
> +       od_frc[3] = hwdata->div_frc << 2;
> +
> +       regmap_bulk_write(vc5->regmap, VC5_OUT_DIV_INT(hwdata->num, 0),
> +                         od_int, 2);
> +       regmap_bulk_write(vc5->regmap, VC5_OUT_DIV_FRAC(hwdata->num, 0),
> +                         od_frc, 4);
> +       return 0;
> +}
> +
> +static const struct clk_ops vc5_fod_ops = {
> +       .recalc_rate    = vc5_fod_recalc_rate,
> +       .round_rate     = vc5_fod_round_rate,
> +       .set_rate       = vc5_fod_set_rate,
> +};
> +
> +static int vc5_clk_out_prepare(struct clk_hw *hw)
> +{
> +       struct vc5_hw_data *hwdata = container_of(hw, struct vc5_hw_data, hw);
> +       struct vc5_driver_data *vc5 = hwdata->vc5;
> +
> +       /* Enable the clock buffer */
> +       regmap_update_bits(vc5->regmap, VC5_CLK_OUTPUT_CFG(hwdata->num, 1),
> +                          VC5_CLK_OUTPUT_CFG1_EN_CLKBUF,
> +                          VC5_CLK_OUTPUT_CFG1_EN_CLKBUF);
> +       return 0;
> +}
> +
> +static void vc5_clk_out_unprepare(struct clk_hw *hw)
> +{
> +       struct vc5_hw_data *hwdata = container_of(hw, struct vc5_hw_data, hw);
> +       struct vc5_driver_data *vc5 = hwdata->vc5;
> +
> +       /* Enable the clock buffer */
> +       regmap_update_bits(vc5->regmap, VC5_CLK_OUTPUT_CFG(hwdata->num, 1),
> +                          VC5_CLK_OUTPUT_CFG1_EN_CLKBUF, 0);
> +}
> +
> +static unsigned char vc5_clk_out_get_parent(struct clk_hw *hw)
> +{
> +       struct vc5_hw_data *hwdata = container_of(hw, struct vc5_hw_data, hw);
> +       struct vc5_driver_data *vc5 = hwdata->vc5;
> +       const u8 mask = VC5_OUT_DIV_CONTROL_SELB_NORM |
> +                       VC5_OUT_DIV_CONTROL_SEL_EXT |
> +                       VC5_OUT_DIV_CONTROL_EN_FOD;
> +       const u8 fodclkmask = VC5_OUT_DIV_CONTROL_SELB_NORM |
> +                             VC5_OUT_DIV_CONTROL_EN_FOD;
> +       const u8 extclk = VC5_OUT_DIV_CONTROL_SELB_NORM |
> +                         VC5_OUT_DIV_CONTROL_SEL_EXT;
> +       unsigned int src;
> +
> +       regmap_read(vc5->regmap, VC5_OUT_DIV_CONTROL(hwdata->num), &src);
> +       src &= mask;
> +
> +       if ((src & fodclkmask) == VC5_OUT_DIV_CONTROL_EN_FOD)
> +               return 0;
> +
> +       if (src == extclk)
> +               return 1;
> +
> +       dev_warn(&vc5->client->dev,
> +                "Invalid clock output configuration (%02x)\n", src);
> +       return 0;
> +}
> +
> +static int vc5_clk_out_set_parent(struct clk_hw *hw, u8 index)
> +{
> +       struct vc5_hw_data *hwdata = container_of(hw, struct vc5_hw_data, hw);
> +       struct vc5_driver_data *vc5 = hwdata->vc5;
> +       const u8 mask = VC5_OUT_DIV_CONTROL_RESET |
> +                       VC5_OUT_DIV_CONTROL_SELB_NORM |
> +                       VC5_OUT_DIV_CONTROL_SEL_EXT |
> +                       VC5_OUT_DIV_CONTROL_EN_FOD;
> +       const u8 extclk = VC5_OUT_DIV_CONTROL_SELB_NORM |
> +                         VC5_OUT_DIV_CONTROL_SEL_EXT;
> +       u8 src = VC5_OUT_DIV_CONTROL_RESET;
> +
> +       if (index == 0)
> +               src |= VC5_OUT_DIV_CONTROL_EN_FOD;
> +       else if (index == 1)
> +               src |= extclk;
> +       else
> +               return -EINVAL;
> +
> +       return regmap_update_bits(vc5->regmap, VC5_OUT_DIV_CONTROL(hwdata->num),
> +                                 mask, src);
> +}
> +
> +static const struct clk_ops vc5_clk_out_ops = {
> +       .prepare        = vc5_clk_out_prepare,
> +       .unprepare      = vc5_clk_out_unprepare,
> +       .set_parent     = vc5_clk_out_set_parent,
> +       .get_parent     = vc5_clk_out_get_parent,
> +};
> +
> +static struct clk_hw *
> +vc5_of_clk_get(struct of_phandle_args *clkspec, void *data)
> +{
> +       struct vc5_driver_data *vc5 = data;
> +       unsigned int idx = clkspec->args[0];
> +
> +       if (idx >= 2) {
> +               pr_err("%s: invalid index %u\n", __func__, idx);
> +               return ERR_PTR(-EINVAL);
> +       }
> +
> +       return &vc5->clk_out[idx].hw;
> +}
> +
> +static int vc5_probe(struct i2c_client *client,
> +                           const struct i2c_device_id *id)
> +{
> +       struct vc5_driver_data *vc5;
> +       struct clk_init_data init;
> +       const char *parent_names[2];
> +       int ret, n;
> +
> +       vc5 = devm_kzalloc(&client->dev, sizeof(*vc5), GFP_KERNEL);
> +       if (vc5 == NULL)
> +               return -ENOMEM;
> +
> +       i2c_set_clientdata(client, vc5);
> +       vc5->client = client;
> +
> +       vc5->pin_xin = devm_clk_get(&client->dev, "xin");
> +       if (PTR_ERR(vc5->pin_xin) == -EPROBE_DEFER)
> +               return -EPROBE_DEFER;
> +
> +       vc5->pin_clkin = devm_clk_get(&client->dev, "clkin");
> +       if (PTR_ERR(vc5->pin_clkin) == -EPROBE_DEFER)
> +               return -EPROBE_DEFER;
> +
> +       vc5->regmap = devm_regmap_init_i2c(client, &vc5_regmap_config);
> +       if (IS_ERR(vc5->regmap)) {
> +               dev_err(&client->dev, "failed to allocate register map\n");
> +               return PTR_ERR(vc5->regmap);
> +       }
> +
> +       if (!IS_ERR(vc5->pin_xin)) {
> +               clk_prepare_enable(vc5->pin_xin);
> +               vc5->pin_xin_name = __clk_get_name(vc5->pin_xin);
> +               vc5->clk_mux_ins |= BIT(0);
> +       }
> +
> +       if (!IS_ERR(vc5->pin_clkin)) {
> +               clk_prepare_enable(vc5->pin_clkin);
> +               vc5->pin_clkin_name = __clk_get_name(vc5->pin_clkin);
> +               vc5->clk_mux_ins |= BIT(1);
> +       }
> +
> +       if (!vc5->clk_mux_ins) {
> +               dev_err(&client->dev, "no input clock specified!\n");
> +               return -EINVAL;
> +       }
> +
> +       /* Register clock input mux */
> +       memset(&init, 0, sizeof(init));
> +       if (vc5->clk_mux_ins == (BIT(0) | BIT(1))) {
> +               parent_names[0] = vc5->pin_xin_name;
> +               parent_names[1] = vc5->pin_clkin_name;
> +               init.num_parents = 2;
> +       } else if (vc5->clk_mux_ins == BIT(0)) {
> +               parent_names[0] = vc5->pin_xin_name;
> +               init.num_parents = 1;
> +       } else {
> +               parent_names[0] = vc5->pin_clkin_name;
> +               init.num_parents = 1;
> +       }
> +       init.name = vc5_mux_names[0];
> +       init.ops = &vc5_mux_ops;
> +       init.flags = 0;
> +       init.parent_names = parent_names;
> +       vc5->clk_mux.init = &init;
> +       ret = devm_clk_hw_register(&client->dev, &vc5->clk_mux);
> +       if (ret) {
> +               dev_err(&client->dev, "unable to register %s\n", init.name);
> +               goto err_clk;
> +       }
> +
> +       /* Register PLL */
> +       memset(&init, 0, sizeof(init));
> +       init.name = vc5_pll_names[0];
> +       init.ops = &vc5_pll_ops;
> +       init.flags = CLK_SET_RATE_PARENT;
> +       init.parent_names = vc5_mux_names;
> +       init.num_parents = 1;
> +       vc5->clk_pll.num = 0;
> +       vc5->clk_pll.vc5 = vc5;
> +       vc5->clk_pll.hw.init = &init;
> +       ret = devm_clk_hw_register(&client->dev, &vc5->clk_pll.hw);
> +       if (ret) {
> +               dev_err(&client->dev, "unable to register %s\n", init.name);
> +               goto err_clk;
> +       }
> +
> +       /* Register FODs */
> +       for (n = 0; n < 2; n++) {
> +               memset(&init, 0, sizeof(init));
> +               init.name = vc5_fod_names[n];
> +               init.ops = &vc5_fod_ops;
> +               init.flags = CLK_SET_RATE_PARENT;
> +               init.parent_names = vc5_pll_names;
> +               init.num_parents = 1;
> +               vc5->clk_fod[n].num = n;
> +               vc5->clk_fod[n].vc5 = vc5;
> +               vc5->clk_fod[n].hw.init = &init;
> +               ret = devm_clk_hw_register(&client->dev, &vc5->clk_fod[n].hw);
> +               if (ret) {
> +                       dev_err(&client->dev, "unable to register %s\n",
> +                               init.name);
> +                       goto err_clk;
> +               }
> +       }
> +
> +       /* Register OUT1 and OUT2 */
> +       for (n = 0; n < 2; n++) {
> +               parent_names[0] = vc5_fod_names[n];
> +               if (n == 0)
> +                       parent_names[1] = vc5_mux_names[0];
> +               else
> +                       parent_names[1] = vc5_clk_out_names[n];
> +
> +               memset(&init, 0, sizeof(init));
> +               init.name = vc5_clk_out_names[n + 1];
> +               init.ops = &vc5_clk_out_ops;
> +               init.flags = CLK_SET_RATE_PARENT;
> +               init.parent_names = parent_names;
> +               init.num_parents = 2;
> +               vc5->clk_out[n].num = n;
> +               vc5->clk_out[n].vc5 = vc5;
> +               vc5->clk_out[n].hw.init = &init;
> +               ret = devm_clk_hw_register(&client->dev,
> +                                          &vc5->clk_out[n].hw);
> +               if (ret) {
> +                       dev_err(&client->dev, "unable to register %s\n",
> +                               init.name);
> +                       goto err_clk;
> +               }
> +       }
> +
> +       ret = of_clk_add_hw_provider(client->dev.of_node, vc5_of_clk_get, vc5);
> +       if (ret) {
> +               dev_err(&client->dev, "unable to add clk provider\n");
> +               goto err_clk;
> +       }
> +
> +       return 0;
> +
> +err_clk:
> +       if (!IS_ERR(vc5->pin_xin))
> +               clk_disable_unprepare(vc5->pin_xin);
> +       if (!IS_ERR(vc5->pin_clkin))
> +               clk_disable_unprepare(vc5->pin_clkin);
> +       return ret;
> +}
> +
> +
> +static const struct i2c_device_id vc5_id[] = {
> +       { "5p49v5923b", 0 },
> +       { }
> +};
> +MODULE_DEVICE_TABLE(i2c, vc5_id);
> +
> +static const struct of_device_id clk_vc5_of_match[] = {
> +       { .compatible = "idt,5p49v5923b" },
> +       { },
> +};
> +
> +MODULE_DEVICE_TABLE(of, clk_vc5_of_match);
> +
> +static struct i2c_driver vc5_driver = {
> +       .driver = {
> +               .name = "vc5",
> +               .of_match_table = clk_vc5_of_match,
> +       },
> +       .probe          = vc5_probe,
> +       .id_table       = vc5_id,
> +};
> +
> +module_i2c_driver(vc5_driver);
> +
> +MODULE_AUTHOR("Marek Vasut <marek.vasut@gmail.com>");
> +MODULE_DESCRIPTION("IDT VersaClock 5 driver");
> +MODULE_LICENSE("GPL");
> --
> 2.10.2

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds
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Laurent Pinchart Jan. 3, 2017, 12:18 p.m. UTC | #2

Hi Marek,

Thank you for the patch.

On Monday 02 Jan 2017 14:46:29 Geert Uytterhoeven wrote:
> On Wed, Dec 28, 2016 at 1:00 AM, Marek Vasut <marek.vasut@gmail.com> wrote:
> > Add driver for IDT VersaClock 5 5P49V5923B chip. This chip has two
> > clock inputs, XTAL or CLK, which are muxed into single PLL/VCO input.
> > The PLL feeds two fractional dividers. Each fractional divider feeds
> > output mux, which allows selecting between clock from the fractional
> > divider itself or from output mux on output N-1. In case of output
> > mux 0, the output N-1 is instead connected to the output from the mux
> > feeding the PLL.
> > 
> > The driver thus far supports only the 5P49V5923B, while it should be
> > easily extensible to the whole 5P49V59xx family of chips as they are
> > all pretty similar.
> > 
> > Signed-off-by: Marek Vasut <marek.vasut@gmail.com>
> > Cc: Michael Turquette <mturquette@baylibre.com>
> > Cc: Stephen Boyd <sboyd@codeaurora.org>
> > ---
> > 
> >  .../devicetree/bindings/clock/idt,versaclock5.txt  |  41 ++
> >  drivers/clk/Kconfig                                |  10 +
> >  drivers/clk/Makefile                               |   1 +
> >  drivers/clk/clk-versaclock5.c                      | 696 ++++++++++++++++
> >  4 files changed, 748 insertions(+)
> >  create mode 100644
> >  Documentation/devicetree/bindings/clock/idt,versaclock5.txt create mode
> >  100644 drivers/clk/clk-versaclock5.c
> > 
> > diff --git a/Documentation/devicetree/bindings/clock/idt,versaclock5.txt
> > b/Documentation/devicetree/bindings/clock/idt,versaclock5.txt new file
> > mode 100644
> > index 0000000..cbe5bc8
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/clock/idt,versaclock5.txt
> > @@ -0,0 +1,41 @@
> > +Binding for IDT VersaClock5 programmable i2c clock generator.
> > +
> > +The IDT VersaClock5 are programmable i2c clock generators providing
> > +from 3 to 12 output clocks.
> > +
> > +==I2C device node==
> > +
> > +Required properties:
> > +- compatible:  shall be one of "idt,5p49v5923b".
> > +- reg:         i2c device address, shall be 0x68 or 0x6a.
> > +- #clock-cells:        from common clock binding; shall be set to 1.
> > +- clocks:      from common clock binding; list of parent clock handles,
> > +               shall be XTAL or CLKIN reference clock. Corresponding
> > +               clock input names are "xin" and "clkin" respectively.

The clock-names property is missing. Given that you can connect two clocks to 
the device and select between them at runtime, you should also specify clearly 
that the clocks property can contain two entries.

> > +- #address-cells: shall be set to 1.
> > +- #size-cells: shall be set to 0.
> > +
> > +==Example==
> > +
> > +/* 25MHz reference crystal */
> > +ref25: ref25m {
> > +       compatible = "fixed-clock";
> > +       #clock-cells = <0>;
> > +       clock-frequency = <25000000>;
> > +};
> > +
> > +i2c-master-node {
> > +
> > +       /* IDT 5P49V5923B i2c clock generator */
> > +       vc5: clock-generator@6a {
> > +               compatible = "idt,5p49v5923b";
> > +               reg = <0x6a>;
> > +               #address-cells = <1>;
> > +               #size-cells = <0>;

Those two properties are not needed.

> > +               #clock-cells = <1>;
> > +
> > +               /* Connect XIN input to 25MHz reference */
> > +               clocks = <&ref25m>;
> > +               clock-names = "xin";
> > +       };
> > +};
> > diff --git a/drivers/clk/Kconfig b/drivers/clk/Kconfig
> > index 6a8ac04..9160e67 100644
> > --- a/drivers/clk/Kconfig
> > +++ b/drivers/clk/Kconfig
> > @@ -198,6 +198,16 @@ config COMMON_CLK_OXNAS
> >         ---help---
> >           Support for the OXNAS SoC Family clocks.
> > 
> > +config COMMON_CLK_VC5
> > +       tristate "Clock driver for IDT VersaClock5 devices"
> > +       depends on I2C
> > +       depends on OF
> > +       select REGMAP_I2C
> > +       help
> > +       ---help---
> > +         This driver supports the IDT VersaClock5 programmable clock
> > +         generator.
> > +
> >  source "drivers/clk/bcm/Kconfig"
> >  source "drivers/clk/hisilicon/Kconfig"
> >  source "drivers/clk/mediatek/Kconfig"
> > diff --git a/drivers/clk/Makefile b/drivers/clk/Makefile
> > index 925081e..e0754d9 100644
> > --- a/drivers/clk/Makefile
> > +++ b/drivers/clk/Makefile
> > @@ -46,6 +46,7 @@ obj-$(CONFIG_ARCH_TANGO)              += clk-tango4.o
> >  obj-$(CONFIG_CLK_TWL6040)              += clk-twl6040.o
> >  obj-$(CONFIG_ARCH_U300)                        += clk-u300.o
> >  obj-$(CONFIG_ARCH_VT8500)              += clk-vt8500.o
> > +obj-$(CONFIG_COMMON_CLK_VC5)           += clk-versaclock5.o
> >  obj-$(CONFIG_COMMON_CLK_WM831X)                += clk-wm831x.o
> >  obj-$(CONFIG_COMMON_CLK_XGENE)         += clk-xgene.o
> > 
> > diff --git a/drivers/clk/clk-versaclock5.c b/drivers/clk/clk-versaclock5.c
> > new file mode 100644
> > index 0000000..286689d
> > --- /dev/null
> > +++ b/drivers/clk/clk-versaclock5.c
> > @@ -0,0 +1,696 @@
> > +/*
> > + * Driver for IDT Versaclock 5
> > + *
> > + * Copyright (C) 2016 Marek Vasut <marek.vasut@gmail.com>

Happy new year :-)

> > + * This program is free software; you can redistribute it and/or modify
> > + * it under the terms of the GNU General Public License as published by
> > + * the Free Software Foundation; either version 2 of the License, or
> > + * (at your option) any later version.
> > + *
> > + * This program is distributed in the hope that it will be useful,
> > + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> > + * GNU General Public License for more details.
> > + */
> > +
> > +/*
> > + * Possible optimizations:
> > + * - Support other chips but 5P49V5923B
> > + * - Use spread spectrum
> > + * - Use integer divider in FOD if applicable
> > + * - register OUT0_SEL_I2CB
> > + */
> > +
> > +#include <linux/clk.h>
> > +#include <linux/clk-provider.h>
> > +#include <linux/delay.h>
> > +#include <linux/i2c.h>
> > +#include <linux/interrupt.h>
> > +#include <linux/mod_devicetable.h>
> > +#include <linux/module.h>
> > +#include <linux/of.h>
> > +#include <linux/rational.h>
> > +#include <linux/regmap.h>
> > +#include <linux/slab.h>
> > +
> > +/* VersaClock5 registers */
> > +#define VC5_OTP_CONTROL                                0x00
> > +
> > +/* Factory-reserved register block */
> > +#define VC5_RSVD_DEVICE_ID                     0x01
> > +#define VC5_RSVD_ADC_GAIN_7_0                  0x02
> > +#define VC5_RSVD_ADC_GAIN_15_8                 0x03
> > +#define VC5_RSVD_ADC_OFFSET_7_0                        0x04
> > +#define VC5_RSVD_ADC_OFFSET_15_8               0x05
> > +#define VC5_RSVD_TEMPY                         0x06
> > +#define VC5_RSVD_OFFSET_TBIN                   0x07
> > +#define VC5_RSVD_GAIN                          0x08
> > +#define VC5_RSVD_TEST_NP                       0x09
> > +#define VC5_RSVD_UNUSED                                0x0a
> > +#define VC5_RSVD_BANDGAP_TRIM_UP               0x0b
> > +#define VC5_RSVD_BANDGAP_TRIM_DN               0x0c
> > +#define VC5_RSVD_CLK_R_12_CLK_AMP_4            0x0d
> > +#define VC5_RSVD_CLK_R_34_CLK_AMP_4            0x0e
> > +#define VC5_RSVD_CLK_AMP_123                   0x0f
> > +
> > +/* Configuration register block */
> > +#define VC5_PRIM_SRC_SHDN                      0x10
> > +#define VC5_PRIM_SRC_SHDN_EN_XTAL              BIT(7)
> > +#define VC5_PRIM_SRC_SHDN_EN_CLKIN             BIT(6)
> > +#define VC5_PRIM_SRC_SHDN_SP                   BIT(1)
> > +#define VC5_PRIM_SRC_SHDN_EN_GBL_SHDN          BIT(0)
> > +
> > +#define VC5_VCO_BAND                           0x11
> > +#define VC5_XTAL_X1_LOAD_CAP                   0x12
> > +#define VC5_XTAL_X2_LOAD_CAP                   0x13
> > +#define VC5_REF_DIVIDER                                0x15
> > +#define VC5_REF_DIVIDER_SEL_PREDIV2            BIT(7)
> > +#define VC5_REF_DIVIDER_REF_DIV(n)             ((n) & 0x3f)
> > +
> > +#define VC5_VCO_CTRL_AND_PREDIV                        0x16
> > +#define VC5_VCO_CTRL_AND_PREDIV_BYPASS_PREDIV  BIT(7)
> > +
> > +#define VC5_FEEDBACK_INT_DIV                   0x17
> > +#define VC5_FEEDBACK_INT_DIV_BITS              0x18
> > +#define VC5_FEEDBACK_FRAC_DIV(n)               (0x19 + (n))
> > +#define VC5_RC_CONTROL0                                0x1e
> > +#define VC5_RC_CONTROL1                                0x1f
> > +/* Register 0x20 is factory reserved */
> > +
> > +/* Output divider control for divider 1,2,3,4 */
> > +#define VC5_OUT_DIV_CONTROL(idx)       (0x21 + ((idx) * 0x10))
> > +#define VC5_OUT_DIV_CONTROL_RESET      BIT(7)
> > +#define VC5_OUT_DIV_CONTROL_SELB_NORM  BIT(3)
> > +#define VC5_OUT_DIV_CONTROL_SEL_EXT    BIT(2)
> > +#define VC5_OUT_DIV_CONTROL_INT_MODE   BIT(1)
> > +#define VC5_OUT_DIV_CONTROL_EN_FOD     BIT(0)
> > +
> > +#define VC5_OUT_DIV_FRAC(idx, n)       (0x22 + ((idx) * 0x10) + (n))
> > +#define VC5_OUT_DIV_FRAC4_OD_SCEE      BIT(1)
> > +
> > +#define VC5_OUT_DIV_STEP_SPREAD(idx, n)        (0x26 + ((idx) * 0x10) +
> > (n))
> > +#define VC5_OUT_DIV_SPREAD_MOD(idx, n) (0x29 + ((idx) * 0x10) + (n))
> > +#define VC5_OUT_DIV_SKEW_INT(idx, n)   (0x2b + ((idx) * 0x10) + (n))
> > +#define VC5_OUT_DIV_INT(idx, n)                (0x2d + ((idx) * 0x10) +
> > (n))
> > +#define VC5_OUT_DIV_SKEW_FRAC(idx)     (0x2f + ((idx) * 0x10))
> > +/* Register 0x30, 0x40, 0x50 is factory reserved */

s/Register/Registers/
s/is/are/

> > +/* Clock control register for clock 1,2 */
> > +#define VC5_CLK_OUTPUT_CFG(idx, n)     (0x60 + ((idx) * 0x2) + (n))
> > +#define VC5_CLK_OUTPUT_CFG1_EN_CLKBUF  BIT(0)
> > +
> > +#define VC5_CLK_OE_SHDN                                0x68
> > +#define VC5_CLK_OS_SHDN                                0x69
> > +
> > +/* PLL/VCO runs between 2.5 GHz and 3.0 GHz */
> > +#define VC5_PLL_VCO_MIN                                2500000000
> > +#define VC5_PLL_VCO_MAX                                3000000000
> > +
> > +struct vc5_driver_data;
> > +
> > +struct vc5_hw_data {
> > +       struct clk_hw           hw;
> > +       struct vc5_driver_data  *vc5;
> > +       unsigned long           div_int;
> > +       unsigned long           div_frc;
> > +       unsigned char           num;

If num really needs to be 8 bits, I'd use u8. Otherwise I'd use unsigned int, 
an unsigned char won't optimize anything.

> > +};
> > +
> > +struct vc5_driver_data {
> > +       struct i2c_client       *client;
> > +       struct regmap           *regmap;
> > +
> > +       struct clk              *pin_xin;
> > +       const char              *pin_xin_name;
> > +       struct clk_hw           clk_xin;
> > +       struct clk              *pin_clkin;
> > +       const char              *pin_clkin_name;
> > +       struct clk_hw           clk_clkin;
> > +       unsigned char           clk_mux_ins;
> > +       struct clk_hw           clk_mux;
> > +       struct vc5_hw_data      clk_pll;
> > +       struct vc5_hw_data      clk_fod[2];
> > +       struct vc5_hw_data      clk_out[3];
> > +};
> > +
> > +static const char * const vc5_input_names[] = {

This seems to be unused.

> > +       "xin", "clkin"
> > +};
> > +
> > +static const char * const vc5_pll_names[] = {
> > +       "pll"
> > +};
> > +
> > +static const char * const vc5_mux_names[] = {
> > +       "mux"
> > +};
> > +
> > +static const char * const vc5_fod_names[] = {
> > +       "fod0", "fod1"
> > +};
> > +
> > +static const char * const vc5_clk_out_names[] = {
> > +       "out0_sel_i2cb", "out1", "out2"
> > +};
> > +
> > +/*
> > + * VersaClock5 i2c regmap
> > + */
> > +static bool vc5_regmap_is_writeable(struct device *dev, unsigned int reg)
> > +{
> > +       /* Factory reserved regs, make them read-only */
> > +       if (reg >= 0 && reg <= 0xf)
> > +               return false;
> > +
> > +       /* Factory reserved regs, make them read-only */
> > +       if (reg == 0x14 || reg == 0x1c || reg == 0x1d)
> > +               return false;
> > +
> > +       return true;
> > +}
> > +
> > +static const struct regmap_config vc5_regmap_config = {
> > +       .reg_bits = 8,
> > +       .val_bits = 8,
> > +       .cache_type = REGCACHE_RBTREE,
> > +       .max_register = 0x69,
> > +       .writeable_reg = vc5_regmap_is_writeable,
> > +};
> > +
> > +/*
> > + * VersaClock5 input multiplexer between XTAL and CLKIN divider
> > + */
> > +static unsigned char vc5_mux_get_parent(struct clk_hw *hw)
> > +{
> > +       struct vc5_driver_data *vc5 =
> > +               container_of(hw, struct vc5_driver_data, clk_mux);
> > +       const u8 mask = VC5_PRIM_SRC_SHDN_EN_XTAL |
> > VC5_PRIM_SRC_SHDN_EN_CLKIN;
> > +       unsigned int src;
> > +
> > +       regmap_read(vc5->regmap, VC5_PRIM_SRC_SHDN, &src);
> > +       src &= mask;
> > +
> > +       if (src == VC5_PRIM_SRC_SHDN_EN_XTAL)
> > +               return 0;
> > +
> > +       if (src == VC5_PRIM_SRC_SHDN_EN_CLKIN)
> > +               return 1;
> > +
> > +       dev_warn(&vc5->client->dev,
> > +                "Invalid clock input configuration (%02x)\n", src);
> > +       return 0;
> > +}
> > +
> > +static int vc5_mux_set_parent(struct clk_hw *hw, u8 index)
> > +{
> > +       struct vc5_driver_data *vc5 =
> > +               container_of(hw, struct vc5_driver_data, clk_mux);
> > +       const u8 mask = VC5_PRIM_SRC_SHDN_EN_XTAL |
> > VC5_PRIM_SRC_SHDN_EN_CLKIN; +       u8 src;
> > +
> > +       if ((index > 1) || !vc5->clk_mux_ins)
> > +               return -EINVAL;
> > +
> > +       if (vc5->clk_mux_ins == (BIT(0) | BIT(1))) {
> > +               if (index == 0)
> > +                       src = VC5_PRIM_SRC_SHDN_EN_XTAL;
> > +               if (index == 1)
> > +                       src = VC5_PRIM_SRC_SHDN_EN_CLKIN;
> > +       } else {
> > +               if (index != 0)
> > +                       return -EINVAL;
> > +
> > +               if (vc5->clk_mux_ins == BIT(0))
> > +                       src = VC5_PRIM_SRC_SHDN_EN_XTAL;
> > +               if (vc5->clk_mux_ins == BIT(1))
> > +                       src = VC5_PRIM_SRC_SHDN_EN_CLKIN;
> > +       }
> > +
> > +       return regmap_update_bits(vc5->regmap, VC5_PRIM_SRC_SHDN, mask,
> > src); +}
> > +
> > +static unsigned long vc5_mux_recalc_rate(struct clk_hw *hw,
> > +                                        unsigned long parent_rate)
> > +{
> > +       struct vc5_driver_data *vc5 =
> > +               container_of(hw, struct vc5_driver_data, clk_mux);
> > +       unsigned long idiv;
> > +       u8 div;
> > +
> > +       /* FIXME: Needs locking ? */

Let's fix it then :-)

> > +       /* CLKIN within range of PLL input, feed directly to PLL. */
> > +       if (parent_rate <= 50000000) {
> > +               regmap_update_bits(vc5->regmap, VC5_VCO_CTRL_AND_PREDIV,
> > +                                  VC5_VCO_CTRL_AND_PREDIV_BYPASS_PREDIV,
> > +                                  VC5_VCO_CTRL_AND_PREDIV_BYPASS_PREDIV);
> > +               regmap_update_bits(vc5->regmap, VC5_REF_DIVIDER, 0xff,
> > 0x00);
> > +               return parent_rate;
> > +       }
> > +
> > +       idiv = DIV_ROUND_UP(parent_rate, 50000000);
> > +       if (idiv > 127)
> > +               return -EINVAL;
> > +
> > +       /* We have dedicated div-2 predivider. */
> > +       if (idiv == 2)
> > +               div = VC5_REF_DIVIDER_SEL_PREDIV2;
> > +       else
> > +               div = VC5_REF_DIVIDER_REF_DIV(idiv);
> > +
> > +       regmap_update_bits(vc5->regmap, VC5_REF_DIVIDER, 0xff, div);
> > +       regmap_update_bits(vc5->regmap, VC5_VCO_CTRL_AND_PREDIV,
> > +                          VC5_VCO_CTRL_AND_PREDIV_BYPASS_PREDIV, 0);
> > +
> > +       return parent_rate / idiv;
> > +}
> > +
> > +static const struct clk_ops vc5_mux_ops = {
> > +       .set_parent     = vc5_mux_set_parent,
> > +       .get_parent     = vc5_mux_get_parent,
> > +       .recalc_rate    = vc5_mux_recalc_rate,
> > +};
> > +
> > +/*
> > + * VersaClock5 PLL/VCO
> > + */
> > +static unsigned long vc5_pll_recalc_rate(struct clk_hw *hw,
> > +                                        unsigned long parent_rate)
> > +{
> > +       struct vc5_hw_data *hwdata = container_of(hw, struct vc5_hw_data,
> > hw);
> > +       struct vc5_driver_data *vc5 = hwdata->vc5;
> > +       u32 div_int, div_frc;
> > +       u8 fb[5];
> > +
> > +       regmap_bulk_read(vc5->regmap, VC5_FEEDBACK_INT_DIV, fb, 5);
> > +
> > +       div_int = (fb[0] << 4) | (fb[1] >> 4);
> > +       div_frc = (fb[2] << 16) | (fb[3] << 8) | fb[4];
> > +
> > +       /* The PLL divider has 12 integer bits and 24 fractional bits */
> > +       return (parent_rate * div_int) + ((parent_rate * div_frc) >> 24);
> > +}
> > +
> > +static long vc5_pll_round_rate(struct clk_hw *hw, unsigned long rate,
> > +                              unsigned long *parent_rate)
> > +{
> > +       struct vc5_hw_data *hwdata = container_of(hw, struct vc5_hw_data,
> > hw);
> > +       unsigned long div_int;
> > +       unsigned long long div_frc;

If the number of bits matter, I'd use u32 and u64 explicitly where applicable.

> > +       if (rate < VC5_PLL_VCO_MIN)
> > +               rate = VC5_PLL_VCO_MIN;
> > +       if (rate > VC5_PLL_VCO_MAX)
> > +               rate = VC5_PLL_VCO_MAX;
> > +
> > +       /* Determine integer part, which is 12 bit wide */
> > +       div_int = rate / *parent_rate;
> > +       if (div_int > 0xfff)
> > +               rate = *parent_rate * 0xfff;
> > +
> > +       /* Determine best fractional part, which is 24 bit wide */
> > +       div_frc = rate % *parent_rate;
> > +       div_frc *= BIT(24) - 1;
> > +       do_div(div_frc, *parent_rate);
> > +
> > +       hwdata->div_int = div_int;
> > +       hwdata->div_frc = (unsigned long)div_frc;
> > +
> > +       return (*parent_rate * div_int) + ((*parent_rate * div_frc) >>
> > 24);
> > +}
> > +
> > +static int vc5_pll_set_rate(struct clk_hw *hw, unsigned long rate,
> > +                           unsigned long parent_rate)
> > +{
> > +       struct vc5_hw_data *hwdata = container_of(hw, struct vc5_hw_data,
> > hw);
> > +       struct vc5_driver_data *vc5 = hwdata->vc5;
> > +       u8 fb[5];
> > +
> > +       fb[0] = hwdata->div_int >> 4;
> > +       fb[1] = hwdata->div_int << 4;
> > +       fb[2] = hwdata->div_frc >> 16;
> > +       fb[3] = hwdata->div_frc >> 8;
> > +       fb[4] = hwdata->div_frc;
> > +
> > +       return regmap_bulk_write(vc5->regmap, VC5_FEEDBACK_INT_DIV, fb,
> > 5);
> > +}
> > +
> > +static const struct clk_ops vc5_pll_ops = {
> > +       .recalc_rate    = vc5_pll_recalc_rate,
> > +       .round_rate     = vc5_pll_round_rate,
> > +       .set_rate       = vc5_pll_set_rate,
> > +};
> > +
> > +static unsigned long vc5_fod_recalc_rate(struct clk_hw *hw,
> > +                                        unsigned long parent_rate)
> > +{
> > +       struct vc5_hw_data *hwdata = container_of(hw, struct vc5_hw_data,
> > hw);
> > +       struct vc5_driver_data *vc5 = hwdata->vc5;
> > +       /* VCO frequency is divided by two before entering FOD */
> > +       u64 f_in = parent_rate / 2;

parent_rate is an unsigned long, f_in doesn't need to be a u64.

> > +       u64 div_int, div_frc;

Can't these two be u32 ?

> > +       u8 od_int[2];
> > +       u8 od_frc[4];
> > +
> > +       regmap_bulk_read(vc5->regmap, VC5_OUT_DIV_INT(hwdata->num, 0),
> > +                        od_int, 2);
> > +       regmap_bulk_read(vc5->regmap, VC5_OUT_DIV_FRAC(hwdata->num, 0),
> > +                        od_frc, 4);
> > +
> > +       div_int = (od_int[0] << 4) | (od_int[1] >> 4);
> > +       div_frc = (od_frc[0] << 22) | (od_frc[1] << 14) |
> > +                 (od_frc[2] << 6) | (od_frc[3] >> 2);
> > +
> > +       /* The PLL divider has 12 integer bits and 30 fractional bits */
> > +       return div64_u64(f_in << 30ULL, (div_int << 30ULL) + div_frc);
> > +}
> > +
> > +static long vc5_fod_round_rate(struct clk_hw *hw, unsigned long rate,
> > +                              unsigned long *parent_rate)
> > +{
> > +       struct vc5_hw_data *hwdata = container_of(hw, struct vc5_hw_data,
> > hw);
> > +       /* VCO frequency is divided by two before entering FOD */
> > +       unsigned long long f_in = *parent_rate / 2;

parent_rate is an unsigned long, f_in doesn't need to be an unsigned long 
long.

> > +       unsigned long div_int;
> > +       unsigned long long div_frc;

If the number of bits matter, I'd use u32 and u64 explicitly where applicable.

> > +
> > +       /* Determine integer part, which is 12 bit wide */
> > +       div_int = f_in / rate;
> > +       /*
> > +        * WARNING: The clock chip does not output signal if the integer
> > part
> > +        *          of the divider is 0xfff and fractional part is non-
> > zero.
> > +        *          Clamp the divider at 0xffe to keep the code simple.
> > +        */
> > +       if (div_int > 0xffe) {
> > +               div_int = 0xffe;
> > +               rate = f_in / div_int;
> > +       }
> > +
> > +       /* Determine best fractional part, which is 30 bit wide */
> > +       div_frc = f_in % rate;
> > +       div_frc *= BIT(30) - 1;
> > +       do_div(div_frc, rate);
> > +
> > +       hwdata->div_int = div_int;
> > +       hwdata->div_frc = (unsigned long)div_frc;
> > +
> > +       return div64_u64(f_in << 30ULL, (div_int << 30ULL) + div_frc);
> > +}
> > +
> > +static int vc5_fod_set_rate(struct clk_hw *hw, unsigned long rate,
> > +                           unsigned long parent_rate)
> > +{
> > +       struct vc5_hw_data *hwdata = container_of(hw, struct vc5_hw_data,
> > hw);
> > +       struct vc5_driver_data *vc5 = hwdata->vc5;
> > +       u8 od_int[2];
> > +       u8 od_frc[4];
> > +
> > +       od_int[0] = hwdata->div_int >> 4;
> > +       od_int[1] = hwdata->div_int << 4;
> > +       od_frc[0] = hwdata->div_frc >> 22;
> > +       od_frc[1] = hwdata->div_frc >> 14;
> > +       od_frc[2] = hwdata->div_frc >> 6;
> > +       od_frc[3] = hwdata->div_frc << 2;
> > +
> > +       regmap_bulk_write(vc5->regmap, VC5_OUT_DIV_INT(hwdata->num, 0),
> > +                         od_int, 2);
> > +       regmap_bulk_write(vc5->regmap, VC5_OUT_DIV_FRAC(hwdata->num, 0),
> > +                         od_frc, 4);
> > +       return 0;
> > +}
> > +
> > +static const struct clk_ops vc5_fod_ops = {
> > +       .recalc_rate    = vc5_fod_recalc_rate,
> > +       .round_rate     = vc5_fod_round_rate,
> > +       .set_rate       = vc5_fod_set_rate,
> > +};
> > +
> > +static int vc5_clk_out_prepare(struct clk_hw *hw)
> > +{
> > +       struct vc5_hw_data *hwdata = container_of(hw, struct vc5_hw_data,
> > hw);
> > +       struct vc5_driver_data *vc5 = hwdata->vc5;
> > +
> > +       /* Enable the clock buffer */
> > +       regmap_update_bits(vc5->regmap, VC5_CLK_OUTPUT_CFG(hwdata->num,
> > 1),
> > +                          VC5_CLK_OUTPUT_CFG1_EN_CLKBUF,
> > +                          VC5_CLK_OUTPUT_CFG1_EN_CLKBUF);
> > +       return 0;
> > +}
> > +
> > +static void vc5_clk_out_unprepare(struct clk_hw *hw)
> > +{
> > +       struct vc5_hw_data *hwdata = container_of(hw, struct vc5_hw_data,
> > hw);
> > +       struct vc5_driver_data *vc5 = hwdata->vc5;
> > +
> > +       /* Enable the clock buffer */
> > +       regmap_update_bits(vc5->regmap, VC5_CLK_OUTPUT_CFG(hwdata->num,
> > 1),
> > +                          VC5_CLK_OUTPUT_CFG1_EN_CLKBUF, 0);
> > +}
> > +
> > +static unsigned char vc5_clk_out_get_parent(struct clk_hw *hw)
> > +{
> > +       struct vc5_hw_data *hwdata = container_of(hw, struct vc5_hw_data,
> > hw);
> > +       struct vc5_driver_data *vc5 = hwdata->vc5;
> > +       const u8 mask = VC5_OUT_DIV_CONTROL_SELB_NORM |
> > +                       VC5_OUT_DIV_CONTROL_SEL_EXT |
> > +                       VC5_OUT_DIV_CONTROL_EN_FOD;
> > +       const u8 fodclkmask = VC5_OUT_DIV_CONTROL_SELB_NORM |
> > +                             VC5_OUT_DIV_CONTROL_EN_FOD;
> > +       const u8 extclk = VC5_OUT_DIV_CONTROL_SELB_NORM |
> > +                         VC5_OUT_DIV_CONTROL_SEL_EXT;
> > +       unsigned int src;
> > +
> > +       regmap_read(vc5->regmap, VC5_OUT_DIV_CONTROL(hwdata->num), &src);
> > +       src &= mask;
> > +
> > +       if ((src & fodclkmask) == VC5_OUT_DIV_CONTROL_EN_FOD)
> > +               return 0;
> > +
> > +       if (src == extclk)
> > +               return 1;
> > +
> > +       dev_warn(&vc5->client->dev,
> > +                "Invalid clock output configuration (%02x)\n", src);
> > +       return 0;
> > +}
> > +
> > +static int vc5_clk_out_set_parent(struct clk_hw *hw, u8 index)
> > +{
> > +       struct vc5_hw_data *hwdata = container_of(hw, struct vc5_hw_data,
> > hw);
> > +       struct vc5_driver_data *vc5 = hwdata->vc5;
> > +       const u8 mask = VC5_OUT_DIV_CONTROL_RESET |
> > +                       VC5_OUT_DIV_CONTROL_SELB_NORM |
> > +                       VC5_OUT_DIV_CONTROL_SEL_EXT |
> > +                       VC5_OUT_DIV_CONTROL_EN_FOD;
> > +       const u8 extclk = VC5_OUT_DIV_CONTROL_SELB_NORM |
> > +                         VC5_OUT_DIV_CONTROL_SEL_EXT;
> > +       u8 src = VC5_OUT_DIV_CONTROL_RESET;
> > +
> > +       if (index == 0)
> > +               src |= VC5_OUT_DIV_CONTROL_EN_FOD;
> > +       else if (index == 1)
> > +               src |= extclk;
> > +       else
> > +               return -EINVAL;

Can this happen given that the number of parents is set to 2 ?

> > +       return regmap_update_bits(vc5->regmap,
> > VC5_OUT_DIV_CONTROL(hwdata->num),
> > +                                 mask, src);
> > +}
> > +
> > +static const struct clk_ops vc5_clk_out_ops = {
> > +       .prepare        = vc5_clk_out_prepare,
> > +       .unprepare      = vc5_clk_out_unprepare,
> > +       .set_parent     = vc5_clk_out_set_parent,
> > +       .get_parent     = vc5_clk_out_get_parent,
> > +};
> > +
> > +static struct clk_hw *
> > +vc5_of_clk_get(struct of_phandle_args *clkspec, void *data)
> > +{
> > +       struct vc5_driver_data *vc5 = data;
> > +       unsigned int idx = clkspec->args[0];
> > +
> > +       if (idx >= 2) {
> > +               pr_err("%s: invalid index %u\n", __func__, idx);
> > +               return ERR_PTR(-EINVAL);
> > +       }
> > +
> > +       return &vc5->clk_out[idx].hw;
> > +}
> > +
> > +static int vc5_probe(struct i2c_client *client,
> > +                           const struct i2c_device_id *id)
> > +{
> > +       struct vc5_driver_data *vc5;
> > +       struct clk_init_data init;
> > +       const char *parent_names[2];
> > +       int ret, n;

n is never negative, you can make it an unsigned int.

> > +
> > +       vc5 = devm_kzalloc(&client->dev, sizeof(*vc5), GFP_KERNEL);
> > +       if (vc5 == NULL)
> > +               return -ENOMEM;
> > +
> > +       i2c_set_clientdata(client, vc5);
> > +       vc5->client = client;
> > +
> > +       vc5->pin_xin = devm_clk_get(&client->dev, "xin");
> > +       if (PTR_ERR(vc5->pin_xin) == -EPROBE_DEFER)
> > +               return -EPROBE_DEFER;
> > +
> > +       vc5->pin_clkin = devm_clk_get(&client->dev, "clkin");
> > +       if (PTR_ERR(vc5->pin_clkin) == -EPROBE_DEFER)
> > +               return -EPROBE_DEFER;
> > +
> > +       vc5->regmap = devm_regmap_init_i2c(client, &vc5_regmap_config);
> > +       if (IS_ERR(vc5->regmap)) {
> > +               dev_err(&client->dev, "failed to allocate register
> > map\n");
> > +               return PTR_ERR(vc5->regmap);
> > +       }
> > +
> > +       if (!IS_ERR(vc5->pin_xin)) {
> > +               clk_prepare_enable(vc5->pin_xin);
> > +               vc5->pin_xin_name = __clk_get_name(vc5->pin_xin);
> > +               vc5->clk_mux_ins |= BIT(0);

You should define macros for the clk_mux_ins bits.

> > +       }
> > +
> > +       if (!IS_ERR(vc5->pin_clkin)) {
> > +               clk_prepare_enable(vc5->pin_clkin);

Shouldn't the input clocks be enabled only when at least one of the outputs is 
enabled ?

> > +               vc5->pin_clkin_name = __clk_get_name(vc5->pin_clkin);
> > +               vc5->clk_mux_ins |= BIT(1);
> > +       }
> > +
> > +       if (!vc5->clk_mux_ins) {
> > +               dev_err(&client->dev, "no input clock specified!\n");
> > +               return -EINVAL;
> > +       }
> > +
> > +       /* Register clock input mux */
> > +       memset(&init, 0, sizeof(init));
> > +       if (vc5->clk_mux_ins == (BIT(0) | BIT(1))) {
> > +               parent_names[0] = vc5->pin_xin_name;
> > +               parent_names[1] = vc5->pin_clkin_name;
> > +               init.num_parents = 2;
> > +       } else if (vc5->clk_mux_ins == BIT(0)) {
> > +               parent_names[0] = vc5->pin_xin_name;
> > +               init.num_parents = 1;
> > +       } else {
> > +               parent_names[0] = vc5->pin_clkin_name;
> > +               init.num_parents = 1;
> > +       }

How about

	if (vc5->clk_mux_ins & BIT(0))
		parent_names[init.num_parents++] = vc5->pin_xin_name;
	if (vc5->clk_mux_ins & BIT(1))
		parent_names[init.num_parents++] = vc5->pin_clkin_name;

Even better, you could move this into you !IS_ERR(vc5->pin_xin) and 
!IS_ERR(vc5->pin_clkin) checks above, and get rid of the temporary 
pin_xin_name and pin_clkin_name fields that are only used for this purpose.

> > +       init.name = vc5_mux_names[0];

I could be mistaken, but aren't clock names supposed to be unique ? If so, you 
couldn't support multiple instances of this device.

> > +       init.ops = &vc5_mux_ops;
> > +       init.flags = 0;
> > +       init.parent_names = parent_names;
> > +       vc5->clk_mux.init = &init;
> > +       ret = devm_clk_hw_register(&client->dev, &vc5->clk_mux);
> > +       if (ret) {
> > +               dev_err(&client->dev, "unable to register %s\n",
> > init.name);
> > +               goto err_clk;
> > +       }
> > +
> > +       /* Register PLL */
> > +       memset(&init, 0, sizeof(init));
> > +       init.name = vc5_pll_names[0];
> > +       init.ops = &vc5_pll_ops;
> > +       init.flags = CLK_SET_RATE_PARENT;
> > +       init.parent_names = vc5_mux_names;
> > +       init.num_parents = 1;
> > +       vc5->clk_pll.num = 0;
> > +       vc5->clk_pll.vc5 = vc5;
> > +       vc5->clk_pll.hw.init = &init;
> > +       ret = devm_clk_hw_register(&client->dev, &vc5->clk_pll.hw);
> > +       if (ret) {
> > +               dev_err(&client->dev, "unable to register %s\n",
> > init.name);
> > +               goto err_clk;
> > +       }
> > +
> > +       /* Register FODs */
> > +       for (n = 0; n < 2; n++) {
> > +               memset(&init, 0, sizeof(init));
> > +               init.name = vc5_fod_names[n];
> > +               init.ops = &vc5_fod_ops;
> > +               init.flags = CLK_SET_RATE_PARENT;
> > +               init.parent_names = vc5_pll_names;
> > +               init.num_parents = 1;
> > +               vc5->clk_fod[n].num = n;
> > +               vc5->clk_fod[n].vc5 = vc5;
> > +               vc5->clk_fod[n].hw.init = &init;
> > +               ret = devm_clk_hw_register(&client->dev,
> > &vc5->clk_fod[n].hw);
> > +               if (ret) {
> > +                       dev_err(&client->dev, "unable to register %s\n",
> > +                               init.name);
> > +                       goto err_clk;
> > +               }
> > +       }
> > +
> > +       /* Register OUT1 and OUT2 */
> > +       for (n = 0; n < 2; n++) {
> > +               parent_names[0] = vc5_fod_names[n];
> > +               if (n == 0)
> > +                       parent_names[1] = vc5_mux_names[0];
> > +               else
> > +                       parent_names[1] = vc5_clk_out_names[n];
> > +
> > +               memset(&init, 0, sizeof(init));
> > +               init.name = vc5_clk_out_names[n + 1];
> > +               init.ops = &vc5_clk_out_ops;
> > +               init.flags = CLK_SET_RATE_PARENT;
> > +               init.parent_names = parent_names;
> > +               init.num_parents = 2;
> > +               vc5->clk_out[n].num = n;
> > +               vc5->clk_out[n].vc5 = vc5;
> > +               vc5->clk_out[n].hw.init = &init;
> > +               ret = devm_clk_hw_register(&client->dev,
> > +                                          &vc5->clk_out[n].hw);
> > +               if (ret) {
> > +                       dev_err(&client->dev, "unable to register %s\n",
> > +                               init.name);
> > +                       goto err_clk;
> > +               }
> > +       }
> > +
> > +       ret = of_clk_add_hw_provider(client->dev.of_node, vc5_of_clk_get,
> > vc5);
> > +       if (ret) {
> > +               dev_err(&client->dev, "unable to add clk provider\n");
> > +               goto err_clk;
> > +       }
> > +
> > +       return 0;
> > +
> > +err_clk:
> > +       if (!IS_ERR(vc5->pin_xin))
> > +               clk_disable_unprepare(vc5->pin_xin);
> > +       if (!IS_ERR(vc5->pin_clkin))
> > +               clk_disable_unprepare(vc5->pin_clkin);
> > +       return ret;
> > +}
> > +
> > +
> > +static const struct i2c_device_id vc5_id[] = {
> > +       { "5p49v5923b", 0 },
> > +       { }
> > +};
> > +MODULE_DEVICE_TABLE(i2c, vc5_id);
> > +
> > +static const struct of_device_id clk_vc5_of_match[] = {
> > +       { .compatible = "idt,5p49v5923b" },
> > +       { },
> > +};
> > +
> > +MODULE_DEVICE_TABLE(of, clk_vc5_of_match);
> > +
> > +static struct i2c_driver vc5_driver = {
> > +       .driver = {
> > +               .name = "vc5",
> > +               .of_match_table = clk_vc5_of_match,
> > +       },
> > +       .probe          = vc5_probe,

No .remove() ? No PM ?

> > +       .id_table       = vc5_id,
> > +};
> > +
> > +module_i2c_driver(vc5_driver);
> > +
> > +MODULE_AUTHOR("Marek Vasut <marek.vasut@gmail.com>");
> > +MODULE_DESCRIPTION("IDT VersaClock 5 driver");
> > +MODULE_LICENSE("GPL");

Marek Vasut Jan. 4, 2017, 4:21 p.m. UTC | #3

On 01/03/2017 01:18 PM, Laurent Pinchart wrote:
> Hi Marek,

Hi,

> Thank you for the patch.
> 
> On Monday 02 Jan 2017 14:46:29 Geert Uytterhoeven wrote:
>> On Wed, Dec 28, 2016 at 1:00 AM, Marek Vasut <marek.vasut@gmail.com> wrote:
>>> Add driver for IDT VersaClock 5 5P49V5923B chip. This chip has two
>>> clock inputs, XTAL or CLK, which are muxed into single PLL/VCO input.
>>> The PLL feeds two fractional dividers. Each fractional divider feeds
>>> output mux, which allows selecting between clock from the fractional
>>> divider itself or from output mux on output N-1. In case of output
>>> mux 0, the output N-1 is instead connected to the output from the mux
>>> feeding the PLL.
>>>
>>> The driver thus far supports only the 5P49V5923B, while it should be
>>> easily extensible to the whole 5P49V59xx family of chips as they are
>>> all pretty similar.
>>>
>>> Signed-off-by: Marek Vasut <marek.vasut@gmail.com>
>>> Cc: Michael Turquette <mturquette@baylibre.com>
>>> Cc: Stephen Boyd <sboyd@codeaurora.org>
>>> ---
>>>
>>>  .../devicetree/bindings/clock/idt,versaclock5.txt  |  41 ++
>>>  drivers/clk/Kconfig                                |  10 +
>>>  drivers/clk/Makefile                               |   1 +
>>>  drivers/clk/clk-versaclock5.c                      | 696 ++++++++++++++++
>>>  4 files changed, 748 insertions(+)
>>>  create mode 100644
>>>  Documentation/devicetree/bindings/clock/idt,versaclock5.txt create mode
>>>  100644 drivers/clk/clk-versaclock5.c
>>>
>>> diff --git a/Documentation/devicetree/bindings/clock/idt,versaclock5.txt
>>> b/Documentation/devicetree/bindings/clock/idt,versaclock5.txt new file
>>> mode 100644
>>> index 0000000..cbe5bc8
>>> --- /dev/null
>>> +++ b/Documentation/devicetree/bindings/clock/idt,versaclock5.txt
>>> @@ -0,0 +1,41 @@
>>> +Binding for IDT VersaClock5 programmable i2c clock generator.
>>> +
>>> +The IDT VersaClock5 are programmable i2c clock generators providing
>>> +from 3 to 12 output clocks.
>>> +
>>> +==I2C device node==
>>> +
>>> +Required properties:
>>> +- compatible:  shall be one of "idt,5p49v5923b".
>>> +- reg:         i2c device address, shall be 0x68 or 0x6a.
>>> +- #clock-cells:        from common clock binding; shall be set to 1.
>>> +- clocks:      from common clock binding; list of parent clock handles,
>>> +               shall be XTAL or CLKIN reference clock. Corresponding
>>> +               clock input names are "xin" and "clkin" respectively.
> 
> The clock-names property is missing. Given that you can connect two clocks to 
> the device and select between them at runtime, you should also specify clearly 
> that the clocks property can contain two entries.

Fixed

>>> +- #address-cells: shall be set to 1.
>>> +- #size-cells: shall be set to 0.
>>> +
>>> +==Example==
>>> +
>>> +/* 25MHz reference crystal */
>>> +ref25: ref25m {
>>> +       compatible = "fixed-clock";
>>> +       #clock-cells = <0>;
>>> +       clock-frequency = <25000000>;
>>> +};
>>> +
>>> +i2c-master-node {
>>> +
>>> +       /* IDT 5P49V5923B i2c clock generator */
>>> +       vc5: clock-generator@6a {
>>> +               compatible = "idt,5p49v5923b";
>>> +               reg = <0x6a>;
>>> +               #address-cells = <1>;
>>> +               #size-cells = <0>;
> 
> Those two properties are not needed.

Right!

>>> +               #clock-cells = <1>;
>>> +
>>> +               /* Connect XIN input to 25MHz reference */
>>> +               clocks = <&ref25m>;
>>> +               clock-names = "xin";
>>> +       };
>>> +};
>>> diff --git a/drivers/clk/Kconfig b/drivers/clk/Kconfig
>>> index 6a8ac04..9160e67 100644
>>> --- a/drivers/clk/Kconfig
>>> +++ b/drivers/clk/Kconfig
>>> @@ -198,6 +198,16 @@ config COMMON_CLK_OXNAS
>>>         ---help---
>>>           Support for the OXNAS SoC Family clocks.
>>>
>>> +config COMMON_CLK_VC5
>>> +       tristate "Clock driver for IDT VersaClock5 devices"
>>> +       depends on I2C
>>> +       depends on OF
>>> +       select REGMAP_I2C
>>> +       help
>>> +       ---help---
>>> +         This driver supports the IDT VersaClock5 programmable clock
>>> +         generator.
>>> +
>>>  source "drivers/clk/bcm/Kconfig"
>>>  source "drivers/clk/hisilicon/Kconfig"
>>>  source "drivers/clk/mediatek/Kconfig"
>>> diff --git a/drivers/clk/Makefile b/drivers/clk/Makefile
>>> index 925081e..e0754d9 100644
>>> --- a/drivers/clk/Makefile
>>> +++ b/drivers/clk/Makefile
>>> @@ -46,6 +46,7 @@ obj-$(CONFIG_ARCH_TANGO)              += clk-tango4.o
>>>  obj-$(CONFIG_CLK_TWL6040)              += clk-twl6040.o
>>>  obj-$(CONFIG_ARCH_U300)                        += clk-u300.o
>>>  obj-$(CONFIG_ARCH_VT8500)              += clk-vt8500.o
>>> +obj-$(CONFIG_COMMON_CLK_VC5)           += clk-versaclock5.o
>>>  obj-$(CONFIG_COMMON_CLK_WM831X)                += clk-wm831x.o
>>>  obj-$(CONFIG_COMMON_CLK_XGENE)         += clk-xgene.o
>>>
>>> diff --git a/drivers/clk/clk-versaclock5.c b/drivers/clk/clk-versaclock5.c
>>> new file mode 100644
>>> index 0000000..286689d
>>> --- /dev/null
>>> +++ b/drivers/clk/clk-versaclock5.c
>>> @@ -0,0 +1,696 @@
>>> +/*
>>> + * Driver for IDT Versaclock 5
>>> + *
>>> + * Copyright (C) 2016 Marek Vasut <marek.vasut@gmail.com>
> 
> Happy new year :-)

Thanks, same to you... and fixed.

>>> + * This program is free software; you can redistribute it and/or modify
>>> + * it under the terms of the GNU General Public License as published by
>>> + * the Free Software Foundation; either version 2 of the License, or
>>> + * (at your option) any later version.
>>> + *
>>> + * This program is distributed in the hope that it will be useful,
>>> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
>>> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
>>> + * GNU General Public License for more details.
>>> + */
>>> +
>>> +/*
>>> + * Possible optimizations:
>>> + * - Support other chips but 5P49V5923B
>>> + * - Use spread spectrum
>>> + * - Use integer divider in FOD if applicable
>>> + * - register OUT0_SEL_I2CB
>>> + */
>>> +
>>> +#include <linux/clk.h>
>>> +#include <linux/clk-provider.h>
>>> +#include <linux/delay.h>
>>> +#include <linux/i2c.h>
>>> +#include <linux/interrupt.h>
>>> +#include <linux/mod_devicetable.h>
>>> +#include <linux/module.h>
>>> +#include <linux/of.h>
>>> +#include <linux/rational.h>
>>> +#include <linux/regmap.h>
>>> +#include <linux/slab.h>
>>> +
>>> +/* VersaClock5 registers */
>>> +#define VC5_OTP_CONTROL                                0x00
>>> +
>>> +/* Factory-reserved register block */
>>> +#define VC5_RSVD_DEVICE_ID                     0x01
>>> +#define VC5_RSVD_ADC_GAIN_7_0                  0x02
>>> +#define VC5_RSVD_ADC_GAIN_15_8                 0x03
>>> +#define VC5_RSVD_ADC_OFFSET_7_0                        0x04
>>> +#define VC5_RSVD_ADC_OFFSET_15_8               0x05
>>> +#define VC5_RSVD_TEMPY                         0x06
>>> +#define VC5_RSVD_OFFSET_TBIN                   0x07
>>> +#define VC5_RSVD_GAIN                          0x08
>>> +#define VC5_RSVD_TEST_NP                       0x09
>>> +#define VC5_RSVD_UNUSED                                0x0a
>>> +#define VC5_RSVD_BANDGAP_TRIM_UP               0x0b
>>> +#define VC5_RSVD_BANDGAP_TRIM_DN               0x0c
>>> +#define VC5_RSVD_CLK_R_12_CLK_AMP_4            0x0d
>>> +#define VC5_RSVD_CLK_R_34_CLK_AMP_4            0x0e
>>> +#define VC5_RSVD_CLK_AMP_123                   0x0f
>>> +
>>> +/* Configuration register block */
>>> +#define VC5_PRIM_SRC_SHDN                      0x10
>>> +#define VC5_PRIM_SRC_SHDN_EN_XTAL              BIT(7)
>>> +#define VC5_PRIM_SRC_SHDN_EN_CLKIN             BIT(6)
>>> +#define VC5_PRIM_SRC_SHDN_SP                   BIT(1)
>>> +#define VC5_PRIM_SRC_SHDN_EN_GBL_SHDN          BIT(0)
>>> +
>>> +#define VC5_VCO_BAND                           0x11
>>> +#define VC5_XTAL_X1_LOAD_CAP                   0x12
>>> +#define VC5_XTAL_X2_LOAD_CAP                   0x13
>>> +#define VC5_REF_DIVIDER                                0x15
>>> +#define VC5_REF_DIVIDER_SEL_PREDIV2            BIT(7)
>>> +#define VC5_REF_DIVIDER_REF_DIV(n)             ((n) & 0x3f)
>>> +
>>> +#define VC5_VCO_CTRL_AND_PREDIV                        0x16
>>> +#define VC5_VCO_CTRL_AND_PREDIV_BYPASS_PREDIV  BIT(7)
>>> +
>>> +#define VC5_FEEDBACK_INT_DIV                   0x17
>>> +#define VC5_FEEDBACK_INT_DIV_BITS              0x18
>>> +#define VC5_FEEDBACK_FRAC_DIV(n)               (0x19 + (n))
>>> +#define VC5_RC_CONTROL0                                0x1e
>>> +#define VC5_RC_CONTROL1                                0x1f
>>> +/* Register 0x20 is factory reserved */
>>> +
>>> +/* Output divider control for divider 1,2,3,4 */
>>> +#define VC5_OUT_DIV_CONTROL(idx)       (0x21 + ((idx) * 0x10))
>>> +#define VC5_OUT_DIV_CONTROL_RESET      BIT(7)
>>> +#define VC5_OUT_DIV_CONTROL_SELB_NORM  BIT(3)
>>> +#define VC5_OUT_DIV_CONTROL_SEL_EXT    BIT(2)
>>> +#define VC5_OUT_DIV_CONTROL_INT_MODE   BIT(1)
>>> +#define VC5_OUT_DIV_CONTROL_EN_FOD     BIT(0)
>>> +
>>> +#define VC5_OUT_DIV_FRAC(idx, n)       (0x22 + ((idx) * 0x10) + (n))
>>> +#define VC5_OUT_DIV_FRAC4_OD_SCEE      BIT(1)
>>> +
>>> +#define VC5_OUT_DIV_STEP_SPREAD(idx, n)        (0x26 + ((idx) * 0x10) +
>>> (n))
>>> +#define VC5_OUT_DIV_SPREAD_MOD(idx, n) (0x29 + ((idx) * 0x10) + (n))
>>> +#define VC5_OUT_DIV_SKEW_INT(idx, n)   (0x2b + ((idx) * 0x10) + (n))
>>> +#define VC5_OUT_DIV_INT(idx, n)                (0x2d + ((idx) * 0x10) +
>>> (n))
>>> +#define VC5_OUT_DIV_SKEW_FRAC(idx)     (0x2f + ((idx) * 0x10))
>>> +/* Register 0x30, 0x40, 0x50 is factory reserved */
> 
> s/Register/Registers/
> s/is/are/
> 
>>> +/* Clock control register for clock 1,2 */
>>> +#define VC5_CLK_OUTPUT_CFG(idx, n)     (0x60 + ((idx) * 0x2) + (n))
>>> +#define VC5_CLK_OUTPUT_CFG1_EN_CLKBUF  BIT(0)
>>> +
>>> +#define VC5_CLK_OE_SHDN                                0x68
>>> +#define VC5_CLK_OS_SHDN                                0x69
>>> +
>>> +/* PLL/VCO runs between 2.5 GHz and 3.0 GHz */
>>> +#define VC5_PLL_VCO_MIN                                2500000000
>>> +#define VC5_PLL_VCO_MAX                                3000000000
>>> +
>>> +struct vc5_driver_data;
>>> +
>>> +struct vc5_hw_data {
>>> +       struct clk_hw           hw;
>>> +       struct vc5_driver_data  *vc5;
>>> +       unsigned long           div_int;
>>> +       unsigned long           div_frc;
>>> +       unsigned char           num;
> 
> If num really needs to be 8 bits, I'd use u8. Otherwise I'd use unsigned int, 
> an unsigned char won't optimize anything.

Fixed all of the above.

>>> +};
>>> +
>>> +struct vc5_driver_data {
>>> +       struct i2c_client       *client;
>>> +       struct regmap           *regmap;
>>> +
>>> +       struct clk              *pin_xin;
>>> +       const char              *pin_xin_name;
>>> +       struct clk_hw           clk_xin;
>>> +       struct clk              *pin_clkin;
>>> +       const char              *pin_clkin_name;
>>> +       struct clk_hw           clk_clkin;
>>> +       unsigned char           clk_mux_ins;
>>> +       struct clk_hw           clk_mux;
>>> +       struct vc5_hw_data      clk_pll;
>>> +       struct vc5_hw_data      clk_fod[2];
>>> +       struct vc5_hw_data      clk_out[3];
>>> +};
>>> +
>>> +static const char * const vc5_input_names[] = {
> 
> This seems to be unused.

Dropped, indeed.

>>> +       "xin", "clkin"
>>> +};
>>> +
>>> +static const char * const vc5_pll_names[] = {
>>> +       "pll"
>>> +};
>>> +
>>> +static const char * const vc5_mux_names[] = {
>>> +       "mux"
>>> +};
>>> +
>>> +static const char * const vc5_fod_names[] = {
>>> +       "fod0", "fod1"
>>> +};
>>> +
>>> +static const char * const vc5_clk_out_names[] = {
>>> +       "out0_sel_i2cb", "out1", "out2"
>>> +};
>>> +
>>> +/*
>>> + * VersaClock5 i2c regmap
>>> + */
>>> +static bool vc5_regmap_is_writeable(struct device *dev, unsigned int reg)
>>> +{
>>> +       /* Factory reserved regs, make them read-only */
>>> +       if (reg >= 0 && reg <= 0xf)
>>> +               return false;
>>> +
>>> +       /* Factory reserved regs, make them read-only */
>>> +       if (reg == 0x14 || reg == 0x1c || reg == 0x1d)
>>> +               return false;
>>> +
>>> +       return true;
>>> +}
>>> +
>>> +static const struct regmap_config vc5_regmap_config = {
>>> +       .reg_bits = 8,
>>> +       .val_bits = 8,
>>> +       .cache_type = REGCACHE_RBTREE,
>>> +       .max_register = 0x69,
>>> +       .writeable_reg = vc5_regmap_is_writeable,
>>> +};
>>> +
>>> +/*
>>> + * VersaClock5 input multiplexer between XTAL and CLKIN divider
>>> + */
>>> +static unsigned char vc5_mux_get_parent(struct clk_hw *hw)
>>> +{
>>> +       struct vc5_driver_data *vc5 =
>>> +               container_of(hw, struct vc5_driver_data, clk_mux);
>>> +       const u8 mask = VC5_PRIM_SRC_SHDN_EN_XTAL |
>>> VC5_PRIM_SRC_SHDN_EN_CLKIN;
>>> +       unsigned int src;
>>> +
>>> +       regmap_read(vc5->regmap, VC5_PRIM_SRC_SHDN, &src);
>>> +       src &= mask;
>>> +
>>> +       if (src == VC5_PRIM_SRC_SHDN_EN_XTAL)
>>> +               return 0;
>>> +
>>> +       if (src == VC5_PRIM_SRC_SHDN_EN_CLKIN)
>>> +               return 1;
>>> +
>>> +       dev_warn(&vc5->client->dev,
>>> +                "Invalid clock input configuration (%02x)\n", src);
>>> +       return 0;
>>> +}
>>> +
>>> +static int vc5_mux_set_parent(struct clk_hw *hw, u8 index)
>>> +{
>>> +       struct vc5_driver_data *vc5 =
>>> +               container_of(hw, struct vc5_driver_data, clk_mux);
>>> +       const u8 mask = VC5_PRIM_SRC_SHDN_EN_XTAL |
>>> VC5_PRIM_SRC_SHDN_EN_CLKIN; +       u8 src;
>>> +
>>> +       if ((index > 1) || !vc5->clk_mux_ins)
>>> +               return -EINVAL;
>>> +
>>> +       if (vc5->clk_mux_ins == (BIT(0) | BIT(1))) {
>>> +               if (index == 0)
>>> +                       src = VC5_PRIM_SRC_SHDN_EN_XTAL;
>>> +               if (index == 1)
>>> +                       src = VC5_PRIM_SRC_SHDN_EN_CLKIN;
>>> +       } else {
>>> +               if (index != 0)
>>> +                       return -EINVAL;
>>> +
>>> +               if (vc5->clk_mux_ins == BIT(0))
>>> +                       src = VC5_PRIM_SRC_SHDN_EN_XTAL;
>>> +               if (vc5->clk_mux_ins == BIT(1))
>>> +                       src = VC5_PRIM_SRC_SHDN_EN_CLKIN;
>>> +       }
>>> +
>>> +       return regmap_update_bits(vc5->regmap, VC5_PRIM_SRC_SHDN, mask,
>>> src); +}
>>> +
>>> +static unsigned long vc5_mux_recalc_rate(struct clk_hw *hw,
>>> +                                        unsigned long parent_rate)
>>> +{
>>> +       struct vc5_driver_data *vc5 =
>>> +               container_of(hw, struct vc5_driver_data, clk_mux);
>>> +       unsigned long idiv;
>>> +       u8 div;
>>> +
>>> +       /* FIXME: Needs locking ? */
> 
> Let's fix it then :-)

I would like to get feedback on this one, does it ?

>>> +       /* CLKIN within range of PLL input, feed directly to PLL. */
>>> +       if (parent_rate <= 50000000) {
>>> +               regmap_update_bits(vc5->regmap, VC5_VCO_CTRL_AND_PREDIV,
>>> +                                  VC5_VCO_CTRL_AND_PREDIV_BYPASS_PREDIV,
>>> +                                  VC5_VCO_CTRL_AND_PREDIV_BYPASS_PREDIV);
>>> +               regmap_update_bits(vc5->regmap, VC5_REF_DIVIDER, 0xff,
>>> 0x00);
>>> +               return parent_rate;
>>> +       }
>>> +
>>> +       idiv = DIV_ROUND_UP(parent_rate, 50000000);
>>> +       if (idiv > 127)
>>> +               return -EINVAL;
>>> +
>>> +       /* We have dedicated div-2 predivider. */
>>> +       if (idiv == 2)
>>> +               div = VC5_REF_DIVIDER_SEL_PREDIV2;
>>> +       else
>>> +               div = VC5_REF_DIVIDER_REF_DIV(idiv);
>>> +
>>> +       regmap_update_bits(vc5->regmap, VC5_REF_DIVIDER, 0xff, div);
>>> +       regmap_update_bits(vc5->regmap, VC5_VCO_CTRL_AND_PREDIV,
>>> +                          VC5_VCO_CTRL_AND_PREDIV_BYPASS_PREDIV, 0);
>>> +
>>> +       return parent_rate / idiv;
>>> +}
>>> +
>>> +static const struct clk_ops vc5_mux_ops = {
>>> +       .set_parent     = vc5_mux_set_parent,
>>> +       .get_parent     = vc5_mux_get_parent,
>>> +       .recalc_rate    = vc5_mux_recalc_rate,
>>> +};
>>> +
>>> +/*
>>> + * VersaClock5 PLL/VCO
>>> + */
>>> +static unsigned long vc5_pll_recalc_rate(struct clk_hw *hw,
>>> +                                        unsigned long parent_rate)
>>> +{
>>> +       struct vc5_hw_data *hwdata = container_of(hw, struct vc5_hw_data,
>>> hw);
>>> +       struct vc5_driver_data *vc5 = hwdata->vc5;
>>> +       u32 div_int, div_frc;
>>> +       u8 fb[5];
>>> +
>>> +       regmap_bulk_read(vc5->regmap, VC5_FEEDBACK_INT_DIV, fb, 5);
>>> +
>>> +       div_int = (fb[0] << 4) | (fb[1] >> 4);
>>> +       div_frc = (fb[2] << 16) | (fb[3] << 8) | fb[4];
>>> +
>>> +       /* The PLL divider has 12 integer bits and 24 fractional bits */
>>> +       return (parent_rate * div_int) + ((parent_rate * div_frc) >> 24);
>>> +}
>>> +
>>> +static long vc5_pll_round_rate(struct clk_hw *hw, unsigned long rate,
>>> +                              unsigned long *parent_rate)
>>> +{
>>> +       struct vc5_hw_data *hwdata = container_of(hw, struct vc5_hw_data,
>>> hw);
>>> +       unsigned long div_int;
>>> +       unsigned long long div_frc;
> 
> If the number of bits matter, I'd use u32 and u64 explicitly where applicable.

OK, fixed.

>>> +       if (rate < VC5_PLL_VCO_MIN)
>>> +               rate = VC5_PLL_VCO_MIN;
>>> +       if (rate > VC5_PLL_VCO_MAX)
>>> +               rate = VC5_PLL_VCO_MAX;
>>> +
>>> +       /* Determine integer part, which is 12 bit wide */
>>> +       div_int = rate / *parent_rate;
>>> +       if (div_int > 0xfff)
>>> +               rate = *parent_rate * 0xfff;
>>> +
>>> +       /* Determine best fractional part, which is 24 bit wide */
>>> +       div_frc = rate % *parent_rate;
>>> +       div_frc *= BIT(24) - 1;
>>> +       do_div(div_frc, *parent_rate);
>>> +
>>> +       hwdata->div_int = div_int;
>>> +       hwdata->div_frc = (unsigned long)div_frc;
>>> +
>>> +       return (*parent_rate * div_int) + ((*parent_rate * div_frc) >>
>>> 24);
>>> +}
>>> +
>>> +static int vc5_pll_set_rate(struct clk_hw *hw, unsigned long rate,
>>> +                           unsigned long parent_rate)
>>> +{
>>> +       struct vc5_hw_data *hwdata = container_of(hw, struct vc5_hw_data,
>>> hw);
>>> +       struct vc5_driver_data *vc5 = hwdata->vc5;
>>> +       u8 fb[5];
>>> +
>>> +       fb[0] = hwdata->div_int >> 4;
>>> +       fb[1] = hwdata->div_int << 4;
>>> +       fb[2] = hwdata->div_frc >> 16;
>>> +       fb[3] = hwdata->div_frc >> 8;
>>> +       fb[4] = hwdata->div_frc;
>>> +
>>> +       return regmap_bulk_write(vc5->regmap, VC5_FEEDBACK_INT_DIV, fb,
>>> 5);
>>> +}
>>> +
>>> +static const struct clk_ops vc5_pll_ops = {
>>> +       .recalc_rate    = vc5_pll_recalc_rate,
>>> +       .round_rate     = vc5_pll_round_rate,
>>> +       .set_rate       = vc5_pll_set_rate,
>>> +};
>>> +
>>> +static unsigned long vc5_fod_recalc_rate(struct clk_hw *hw,
>>> +                                        unsigned long parent_rate)
>>> +{
>>> +       struct vc5_hw_data *hwdata = container_of(hw, struct vc5_hw_data,
>>> hw);
>>> +       struct vc5_driver_data *vc5 = hwdata->vc5;
>>> +       /* VCO frequency is divided by two before entering FOD */
>>> +       u64 f_in = parent_rate / 2;
> 
> parent_rate is an unsigned long, f_in doesn't need to be a u64.
> 
>>> +       u64 div_int, div_frc;
> 
> Can't these two be u32 ?

Yes and I dropped u64 where applicable.

>>> +       u8 od_int[2];
>>> +       u8 od_frc[4];
>>> +
>>> +       regmap_bulk_read(vc5->regmap, VC5_OUT_DIV_INT(hwdata->num, 0),
>>> +                        od_int, 2);
>>> +       regmap_bulk_read(vc5->regmap, VC5_OUT_DIV_FRAC(hwdata->num, 0),
>>> +                        od_frc, 4);
>>> +
>>> +       div_int = (od_int[0] << 4) | (od_int[1] >> 4);
>>> +       div_frc = (od_frc[0] << 22) | (od_frc[1] << 14) |
>>> +                 (od_frc[2] << 6) | (od_frc[3] >> 2);
>>> +
>>> +       /* The PLL divider has 12 integer bits and 30 fractional bits */
>>> +       return div64_u64(f_in << 30ULL, (div_int << 30ULL) + div_frc);
>>> +}
>>> +
>>> +static long vc5_fod_round_rate(struct clk_hw *hw, unsigned long rate,
>>> +                              unsigned long *parent_rate)
>>> +{
>>> +       struct vc5_hw_data *hwdata = container_of(hw, struct vc5_hw_data,
>>> hw);
>>> +       /* VCO frequency is divided by two before entering FOD */
>>> +       unsigned long long f_in = *parent_rate / 2;
> 
> parent_rate is an unsigned long, f_in doesn't need to be an unsigned long 
> long.
> 
>>> +       unsigned long div_int;
>>> +       unsigned long long div_frc;
> 
> If the number of bits matter, I'd use u32 and u64 explicitly where applicable.

Yes, fixed

>>> +
>>> +       /* Determine integer part, which is 12 bit wide */
>>> +       div_int = f_in / rate;
>>> +       /*
>>> +        * WARNING: The clock chip does not output signal if the integer
>>> part
>>> +        *          of the divider is 0xfff and fractional part is non-
>>> zero.
>>> +        *          Clamp the divider at 0xffe to keep the code simple.
>>> +        */
>>> +       if (div_int > 0xffe) {
>>> +               div_int = 0xffe;
>>> +               rate = f_in / div_int;
>>> +       }
>>> +
>>> +       /* Determine best fractional part, which is 30 bit wide */
>>> +       div_frc = f_in % rate;
>>> +       div_frc *= BIT(30) - 1;
>>> +       do_div(div_frc, rate);
>>> +
>>> +       hwdata->div_int = div_int;
>>> +       hwdata->div_frc = (unsigned long)div_frc;
>>> +
>>> +       return div64_u64(f_in << 30ULL, (div_int << 30ULL) + div_frc);
>>> +}
>>> +
>>> +static int vc5_fod_set_rate(struct clk_hw *hw, unsigned long rate,
>>> +                           unsigned long parent_rate)
>>> +{
>>> +       struct vc5_hw_data *hwdata = container_of(hw, struct vc5_hw_data,
>>> hw);
>>> +       struct vc5_driver_data *vc5 = hwdata->vc5;
>>> +       u8 od_int[2];
>>> +       u8 od_frc[4];
>>> +
>>> +       od_int[0] = hwdata->div_int >> 4;
>>> +       od_int[1] = hwdata->div_int << 4;
>>> +       od_frc[0] = hwdata->div_frc >> 22;
>>> +       od_frc[1] = hwdata->div_frc >> 14;
>>> +       od_frc[2] = hwdata->div_frc >> 6;
>>> +       od_frc[3] = hwdata->div_frc << 2;
>>> +
>>> +       regmap_bulk_write(vc5->regmap, VC5_OUT_DIV_INT(hwdata->num, 0),
>>> +                         od_int, 2);
>>> +       regmap_bulk_write(vc5->regmap, VC5_OUT_DIV_FRAC(hwdata->num, 0),
>>> +                         od_frc, 4);
>>> +       return 0;
>>> +}
>>> +
>>> +static const struct clk_ops vc5_fod_ops = {
>>> +       .recalc_rate    = vc5_fod_recalc_rate,
>>> +       .round_rate     = vc5_fod_round_rate,
>>> +       .set_rate       = vc5_fod_set_rate,
>>> +};
>>> +
>>> +static int vc5_clk_out_prepare(struct clk_hw *hw)
>>> +{
>>> +       struct vc5_hw_data *hwdata = container_of(hw, struct vc5_hw_data,
>>> hw);
>>> +       struct vc5_driver_data *vc5 = hwdata->vc5;
>>> +
>>> +       /* Enable the clock buffer */
>>> +       regmap_update_bits(vc5->regmap, VC5_CLK_OUTPUT_CFG(hwdata->num,
>>> 1),
>>> +                          VC5_CLK_OUTPUT_CFG1_EN_CLKBUF,
>>> +                          VC5_CLK_OUTPUT_CFG1_EN_CLKBUF);
>>> +       return 0;
>>> +}
>>> +
>>> +static void vc5_clk_out_unprepare(struct clk_hw *hw)
>>> +{
>>> +       struct vc5_hw_data *hwdata = container_of(hw, struct vc5_hw_data,
>>> hw);
>>> +       struct vc5_driver_data *vc5 = hwdata->vc5;
>>> +
>>> +       /* Enable the clock buffer */
>>> +       regmap_update_bits(vc5->regmap, VC5_CLK_OUTPUT_CFG(hwdata->num,
>>> 1),
>>> +                          VC5_CLK_OUTPUT_CFG1_EN_CLKBUF, 0);
>>> +}
>>> +
>>> +static unsigned char vc5_clk_out_get_parent(struct clk_hw *hw)
>>> +{
>>> +       struct vc5_hw_data *hwdata = container_of(hw, struct vc5_hw_data,
>>> hw);
>>> +       struct vc5_driver_data *vc5 = hwdata->vc5;
>>> +       const u8 mask = VC5_OUT_DIV_CONTROL_SELB_NORM |
>>> +                       VC5_OUT_DIV_CONTROL_SEL_EXT |
>>> +                       VC5_OUT_DIV_CONTROL_EN_FOD;
>>> +       const u8 fodclkmask = VC5_OUT_DIV_CONTROL_SELB_NORM |
>>> +                             VC5_OUT_DIV_CONTROL_EN_FOD;
>>> +       const u8 extclk = VC5_OUT_DIV_CONTROL_SELB_NORM |
>>> +                         VC5_OUT_DIV_CONTROL_SEL_EXT;
>>> +       unsigned int src;
>>> +
>>> +       regmap_read(vc5->regmap, VC5_OUT_DIV_CONTROL(hwdata->num), &src);
>>> +       src &= mask;
>>> +
>>> +       if ((src & fodclkmask) == VC5_OUT_DIV_CONTROL_EN_FOD)
>>> +               return 0;
>>> +
>>> +       if (src == extclk)
>>> +               return 1;
>>> +
>>> +       dev_warn(&vc5->client->dev,
>>> +                "Invalid clock output configuration (%02x)\n", src);
>>> +       return 0;
>>> +}
>>> +
>>> +static int vc5_clk_out_set_parent(struct clk_hw *hw, u8 index)
>>> +{
>>> +       struct vc5_hw_data *hwdata = container_of(hw, struct vc5_hw_data,
>>> hw);
>>> +       struct vc5_driver_data *vc5 = hwdata->vc5;
>>> +       const u8 mask = VC5_OUT_DIV_CONTROL_RESET |
>>> +                       VC5_OUT_DIV_CONTROL_SELB_NORM |
>>> +                       VC5_OUT_DIV_CONTROL_SEL_EXT |
>>> +                       VC5_OUT_DIV_CONTROL_EN_FOD;
>>> +       const u8 extclk = VC5_OUT_DIV_CONTROL_SELB_NORM |
>>> +                         VC5_OUT_DIV_CONTROL_SEL_EXT;
>>> +       u8 src = VC5_OUT_DIV_CONTROL_RESET;
>>> +
>>> +       if (index == 0)
>>> +               src |= VC5_OUT_DIV_CONTROL_EN_FOD;
>>> +       else if (index == 1)
>>> +               src |= extclk;
>>> +       else
>>> +               return -EINVAL;
> 
> Can this happen given that the number of parents is set to 2 ?

I believe it should not happen, but I'd rather sanitize the input here
to be safe. Shall I remove it ?

>>> +       return regmap_update_bits(vc5->regmap,
>>> VC5_OUT_DIV_CONTROL(hwdata->num),
>>> +                                 mask, src);
>>> +}
>>> +
>>> +static const struct clk_ops vc5_clk_out_ops = {
>>> +       .prepare        = vc5_clk_out_prepare,
>>> +       .unprepare      = vc5_clk_out_unprepare,
>>> +       .set_parent     = vc5_clk_out_set_parent,
>>> +       .get_parent     = vc5_clk_out_get_parent,
>>> +};
>>> +
>>> +static struct clk_hw *
>>> +vc5_of_clk_get(struct of_phandle_args *clkspec, void *data)
>>> +{
>>> +       struct vc5_driver_data *vc5 = data;
>>> +       unsigned int idx = clkspec->args[0];
>>> +
>>> +       if (idx >= 2) {
>>> +               pr_err("%s: invalid index %u\n", __func__, idx);
>>> +               return ERR_PTR(-EINVAL);
>>> +       }
>>> +
>>> +       return &vc5->clk_out[idx].hw;
>>> +}
>>> +
>>> +static int vc5_probe(struct i2c_client *client,
>>> +                           const struct i2c_device_id *id)
>>> +{
>>> +       struct vc5_driver_data *vc5;
>>> +       struct clk_init_data init;
>>> +       const char *parent_names[2];
>>> +       int ret, n;
> 
> n is never negative, you can make it an unsigned int.

Fixed

>>> +
>>> +       vc5 = devm_kzalloc(&client->dev, sizeof(*vc5), GFP_KERNEL);
>>> +       if (vc5 == NULL)
>>> +               return -ENOMEM;
>>> +
>>> +       i2c_set_clientdata(client, vc5);
>>> +       vc5->client = client;
>>> +
>>> +       vc5->pin_xin = devm_clk_get(&client->dev, "xin");
>>> +       if (PTR_ERR(vc5->pin_xin) == -EPROBE_DEFER)
>>> +               return -EPROBE_DEFER;
>>> +
>>> +       vc5->pin_clkin = devm_clk_get(&client->dev, "clkin");
>>> +       if (PTR_ERR(vc5->pin_clkin) == -EPROBE_DEFER)
>>> +               return -EPROBE_DEFER;
>>> +
>>> +       vc5->regmap = devm_regmap_init_i2c(client, &vc5_regmap_config);
>>> +       if (IS_ERR(vc5->regmap)) {
>>> +               dev_err(&client->dev, "failed to allocate register
>>> map\n");
>>> +               return PTR_ERR(vc5->regmap);
>>> +       }
>>> +
>>> +       if (!IS_ERR(vc5->pin_xin)) {
>>> +               clk_prepare_enable(vc5->pin_xin);
>>> +               vc5->pin_xin_name = __clk_get_name(vc5->pin_xin);
>>> +               vc5->clk_mux_ins |= BIT(0);
> 
> You should define macros for the clk_mux_ins bits.

Fixed

>>> +       }
>>> +
>>> +       if (!IS_ERR(vc5->pin_clkin)) {
>>> +               clk_prepare_enable(vc5->pin_clkin);
> 
> Shouldn't the input clocks be enabled only when at least one of the outputs is 
> enabled ?

Yes, I'll have to drill into this a bit.

>>> +               vc5->pin_clkin_name = __clk_get_name(vc5->pin_clkin);
>>> +               vc5->clk_mux_ins |= BIT(1);
>>> +       }
>>> +
>>> +       if (!vc5->clk_mux_ins) {
>>> +               dev_err(&client->dev, "no input clock specified!\n");
>>> +               return -EINVAL;
>>> +       }
>>> +
>>> +       /* Register clock input mux */
>>> +       memset(&init, 0, sizeof(init));
>>> +       if (vc5->clk_mux_ins == (BIT(0) | BIT(1))) {
>>> +               parent_names[0] = vc5->pin_xin_name;
>>> +               parent_names[1] = vc5->pin_clkin_name;
>>> +               init.num_parents = 2;
>>> +       } else if (vc5->clk_mux_ins == BIT(0)) {
>>> +               parent_names[0] = vc5->pin_xin_name;
>>> +               init.num_parents = 1;
>>> +       } else {
>>> +               parent_names[0] = vc5->pin_clkin_name;
>>> +               init.num_parents = 1;
>>> +       }
> 
> How about
> 
> 	if (vc5->clk_mux_ins & BIT(0))
> 		parent_names[init.num_parents++] = vc5->pin_xin_name;
> 	if (vc5->clk_mux_ins & BIT(1))
> 		parent_names[init.num_parents++] = vc5->pin_clkin_name;
> 
> Even better, you could move this into you !IS_ERR(vc5->pin_xin) and 
> !IS_ERR(vc5->pin_clkin) checks above, and get rid of the temporary 
> pin_xin_name and pin_clkin_name fields that are only used for this purpose.

That's nice indeed.

>>> +       init.name = vc5_mux_names[0];
> 
> I could be mistaken, but aren't clock names supposed to be unique ? If so, you 
> couldn't support multiple instances of this device.

By this device, you mean the mux or the clock chip ? In case of the
former, if there is a VC5 with multiple muxes, the clock structure would
need to be reworked indeed. In the later case, you access the
device node (which is unique) and then the elements of it, which is
again unique.

>>> +       init.ops = &vc5_mux_ops;
>>> +       init.flags = 0;
>>> +       init.parent_names = parent_names;
>>> +       vc5->clk_mux.init = &init;
>>> +       ret = devm_clk_hw_register(&client->dev, &vc5->clk_mux);
>>> +       if (ret) {
>>> +               dev_err(&client->dev, "unable to register %s\n",
>>> init.name);
>>> +               goto err_clk;
>>> +       }
>>> +
>>> +       /* Register PLL */
>>> +       memset(&init, 0, sizeof(init));
>>> +       init.name = vc5_pll_names[0];
>>> +       init.ops = &vc5_pll_ops;
>>> +       init.flags = CLK_SET_RATE_PARENT;
>>> +       init.parent_names = vc5_mux_names;
>>> +       init.num_parents = 1;
>>> +       vc5->clk_pll.num = 0;
>>> +       vc5->clk_pll.vc5 = vc5;
>>> +       vc5->clk_pll.hw.init = &init;
>>> +       ret = devm_clk_hw_register(&client->dev, &vc5->clk_pll.hw);
>>> +       if (ret) {
>>> +               dev_err(&client->dev, "unable to register %s\n",
>>> init.name);
>>> +               goto err_clk;
>>> +       }
>>> +
>>> +       /* Register FODs */
>>> +       for (n = 0; n < 2; n++) {
>>> +               memset(&init, 0, sizeof(init));
>>> +               init.name = vc5_fod_names[n];
>>> +               init.ops = &vc5_fod_ops;
>>> +               init.flags = CLK_SET_RATE_PARENT;
>>> +               init.parent_names = vc5_pll_names;
>>> +               init.num_parents = 1;
>>> +               vc5->clk_fod[n].num = n;
>>> +               vc5->clk_fod[n].vc5 = vc5;
>>> +               vc5->clk_fod[n].hw.init = &init;
>>> +               ret = devm_clk_hw_register(&client->dev,
>>> &vc5->clk_fod[n].hw);
>>> +               if (ret) {
>>> +                       dev_err(&client->dev, "unable to register %s\n",
>>> +                               init.name);
>>> +                       goto err_clk;
>>> +               }
>>> +       }
>>> +
>>> +       /* Register OUT1 and OUT2 */
>>> +       for (n = 0; n < 2; n++) {
>>> +               parent_names[0] = vc5_fod_names[n];
>>> +               if (n == 0)
>>> +                       parent_names[1] = vc5_mux_names[0];
>>> +               else
>>> +                       parent_names[1] = vc5_clk_out_names[n];
>>> +
>>> +               memset(&init, 0, sizeof(init));
>>> +               init.name = vc5_clk_out_names[n + 1];
>>> +               init.ops = &vc5_clk_out_ops;
>>> +               init.flags = CLK_SET_RATE_PARENT;
>>> +               init.parent_names = parent_names;
>>> +               init.num_parents = 2;
>>> +               vc5->clk_out[n].num = n;
>>> +               vc5->clk_out[n].vc5 = vc5;
>>> +               vc5->clk_out[n].hw.init = &init;
>>> +               ret = devm_clk_hw_register(&client->dev,
>>> +                                          &vc5->clk_out[n].hw);
>>> +               if (ret) {
>>> +                       dev_err(&client->dev, "unable to register %s\n",
>>> +                               init.name);
>>> +                       goto err_clk;
>>> +               }
>>> +       }
>>> +
>>> +       ret = of_clk_add_hw_provider(client->dev.of_node, vc5_of_clk_get,
>>> vc5);
>>> +       if (ret) {
>>> +               dev_err(&client->dev, "unable to add clk provider\n");
>>> +               goto err_clk;
>>> +       }
>>> +
>>> +       return 0;
>>> +
>>> +err_clk:
>>> +       if (!IS_ERR(vc5->pin_xin))
>>> +               clk_disable_unprepare(vc5->pin_xin);
>>> +       if (!IS_ERR(vc5->pin_clkin))
>>> +               clk_disable_unprepare(vc5->pin_clkin);
>>> +       return ret;
>>> +}
>>> +
>>> +
>>> +static const struct i2c_device_id vc5_id[] = {
>>> +       { "5p49v5923b", 0 },
>>> +       { }
>>> +};
>>> +MODULE_DEVICE_TABLE(i2c, vc5_id);
>>> +
>>> +static const struct of_device_id clk_vc5_of_match[] = {
>>> +       { .compatible = "idt,5p49v5923b" },
>>> +       { },
>>> +};
>>> +
>>> +MODULE_DEVICE_TABLE(of, clk_vc5_of_match);
>>> +
>>> +static struct i2c_driver vc5_driver = {
>>> +       .driver = {
>>> +               .name = "vc5",
>>> +               .of_match_table = clk_vc5_of_match,
>>> +       },
>>> +       .probe          = vc5_probe,
> 
> No .remove() ? No PM ?

Remove added, I'm kinda surprised by how many of the i2c clock drivers
don't have .remove though. As for PM, I'll look into that.

>>> +       .id_table       = vc5_id,
>>> +};
>>> +
>>> +module_i2c_driver(vc5_driver);
>>> +
>>> +MODULE_AUTHOR("Marek Vasut <marek.vasut@gmail.com>");
>>> +MODULE_DESCRIPTION("IDT VersaClock 5 driver");
>>> +MODULE_LICENSE("GPL");

Laurent Pinchart Jan. 5, 2017, 2:13 p.m. UTC | #4

Hi Marek,

On Wednesday 04 Jan 2017 17:21:43 Marek Vasut wrote:
> On 01/03/2017 01:18 PM, Laurent Pinchart wrote:
> > On Monday 02 Jan 2017 14:46:29 Geert Uytterhoeven wrote:
> >> On Wed, Dec 28, 2016 at 1:00 AM, Marek Vasut wrote:
> >>> Add driver for IDT VersaClock 5 5P49V5923B chip. This chip has two
> >>> clock inputs, XTAL or CLK, which are muxed into single PLL/VCO input.
> >>> The PLL feeds two fractional dividers. Each fractional divider feeds
> >>> output mux, which allows selecting between clock from the fractional
> >>> divider itself or from output mux on output N-1. In case of output
> >>> mux 0, the output N-1 is instead connected to the output from the mux
> >>> feeding the PLL.
> >>> 
> >>> The driver thus far supports only the 5P49V5923B, while it should be
> >>> easily extensible to the whole 5P49V59xx family of chips as they are
> >>> all pretty similar.
> >>> 
> >>> Signed-off-by: Marek Vasut <marek.vasut@gmail.com>
> >>> Cc: Michael Turquette <mturquette@baylibre.com>
> >>> Cc: Stephen Boyd <sboyd@codeaurora.org>
> >>> ---
> >>> 
> >>>  .../devicetree/bindings/clock/idt,versaclock5.txt  |  41 ++
> >>>  drivers/clk/Kconfig                                |  10 +
> >>>  drivers/clk/Makefile                               |   1 +
> >>>  drivers/clk/clk-versaclock5.c                      | 696 +++++++++++++
> >>>  4 files changed, 748 insertions(+)
> >>>  create mode 100644
> >>>  Documentation/devicetree/bindings/clock/idt,versaclock5.txt create mode
> >>>  100644 drivers/clk/clk-versaclock5.c

[snip]

> >>> diff --git a/drivers/clk/clk-versaclock5.c
> >>> b/drivers/clk/clk-versaclock5.c
> >>> new file mode 100644
> >>> index 0000000..286689d
> >>> --- /dev/null
> >>> +++ b/drivers/clk/clk-versaclock5.c

[snip]

> >>> +static unsigned long vc5_mux_recalc_rate(struct clk_hw *hw,
> >>> +                                        unsigned long parent_rate)
> >>> +{
> >>> +       struct vc5_driver_data *vc5 =
> >>> +               container_of(hw, struct vc5_driver_data, clk_mux);
> >>> +       unsigned long idiv;
> >>> +       u8 div;
> >>> +
> >>> +       /* FIXME: Needs locking ? */
> > 
> > Let's fix it then :-)
> 
> I would like to get feedback on this one, does it ?

That's a question for Mike or Stephen I believe.

> >>> +       /* CLKIN within range of PLL input, feed directly to PLL. */
> >>> +       if (parent_rate <= 50000000) {
> >>> +               regmap_update_bits(vc5->regmap, VC5_VCO_CTRL_AND_PREDIV,
> >>> +                                 
> >>> VC5_VCO_CTRL_AND_PREDIV_BYPASS_PREDIV,
> >>> +                                 
> >>> VC5_VCO_CTRL_AND_PREDIV_BYPASS_PREDIV);
> >>> +               regmap_update_bits(vc5->regmap, VC5_REF_DIVIDER, 0xff,
> >>> 0x00);
> >>> +               return parent_rate;
> >>> +       }
> >>> +
> >>> +       idiv = DIV_ROUND_UP(parent_rate, 50000000);
> >>> +       if (idiv > 127)
> >>> +               return -EINVAL;
> >>> +
> >>> +       /* We have dedicated div-2 predivider. */
> >>> +       if (idiv == 2)
> >>> +               div = VC5_REF_DIVIDER_SEL_PREDIV2;
> >>> +       else
> >>> +               div = VC5_REF_DIVIDER_REF_DIV(idiv);
> >>> +
> >>> +       regmap_update_bits(vc5->regmap, VC5_REF_DIVIDER, 0xff, div);
> >>> +       regmap_update_bits(vc5->regmap, VC5_VCO_CTRL_AND_PREDIV,
> >>> +                          VC5_VCO_CTRL_AND_PREDIV_BYPASS_PREDIV, 0);
> >>> +
> >>> +       return parent_rate / idiv;
> >>> +}

[snip]

> >>> +static int vc5_clk_out_set_parent(struct clk_hw *hw, u8 index)
> >>> +{
> >>> +       struct vc5_hw_data *hwdata = container_of(hw, struct
> >>> vc5_hw_data, hw);
> >>> +       struct vc5_driver_data *vc5 = hwdata->vc5;
> >>> +       const u8 mask = VC5_OUT_DIV_CONTROL_RESET |
> >>> +                       VC5_OUT_DIV_CONTROL_SELB_NORM |
> >>> +                       VC5_OUT_DIV_CONTROL_SEL_EXT |
> >>> +                       VC5_OUT_DIV_CONTROL_EN_FOD;
> >>> +       const u8 extclk = VC5_OUT_DIV_CONTROL_SELB_NORM |
> >>> +                         VC5_OUT_DIV_CONTROL_SEL_EXT;
> >>> +       u8 src = VC5_OUT_DIV_CONTROL_RESET;
> >>> +
> >>> +       if (index == 0)
> >>> +               src |= VC5_OUT_DIV_CONTROL_EN_FOD;
> >>> +       else if (index == 1)
> >>> +               src |= extclk;
> >>> +       else
> >>> +               return -EINVAL;
> > 
> > Can this happen given that the number of parents is set to 2 ?
> 
> I believe it should not happen, but I'd rather sanitize the input here
> to be safe. Shall I remove it ?

I'd remove it as it can't happen. Being called with index > 1 would be similar 
to being called with hw == NULL, which you don't check explicitly. I don't 
think we should sanitize every input parameter value in every driver when the 
core is supposed to take care of that.

> >>> +       return regmap_update_bits(vc5->regmap,
> >>> VC5_OUT_DIV_CONTROL(hwdata->num),
> >>> +                                 mask, src);
> >>> +}

[snip]

> >>> +static int vc5_probe(struct i2c_client *client,
> >>> +                           const struct i2c_device_id *id)
> >>> +{
> >>> +       struct vc5_driver_data *vc5;
> >>> +       struct clk_init_data init;
> >>> +       const char *parent_names[2];
> >>> +       int ret, n;
> > 
> > n is never negative, you can make it an unsigned int.
> 
> Fixed
> 
> >>> +
> >>> +       vc5 = devm_kzalloc(&client->dev, sizeof(*vc5), GFP_KERNEL);
> >>> +       if (vc5 == NULL)
> >>> +               return -ENOMEM;
> >>> +
> >>> +       i2c_set_clientdata(client, vc5);
> >>> +       vc5->client = client;
> >>> +
> >>> +       vc5->pin_xin = devm_clk_get(&client->dev, "xin");
> >>> +       if (PTR_ERR(vc5->pin_xin) == -EPROBE_DEFER)
> >>> +               return -EPROBE_DEFER;
> >>> +
> >>> +       vc5->pin_clkin = devm_clk_get(&client->dev, "clkin");
> >>> +       if (PTR_ERR(vc5->pin_clkin) == -EPROBE_DEFER)
> >>> +               return -EPROBE_DEFER;
> >>> +
> >>> +       vc5->regmap = devm_regmap_init_i2c(client, &vc5_regmap_config);
> >>> +       if (IS_ERR(vc5->regmap)) {
> >>> +               dev_err(&client->dev, "failed to allocate register
> >>> map\n");
> >>> +               return PTR_ERR(vc5->regmap);
> >>> +       }
> >>> +
> >>> +       if (!IS_ERR(vc5->pin_xin)) {
> >>> +               clk_prepare_enable(vc5->pin_xin);
> >>> +               vc5->pin_xin_name = __clk_get_name(vc5->pin_xin);
> >>> +               vc5->clk_mux_ins |= BIT(0);
> > 
> > You should define macros for the clk_mux_ins bits.
> 
> Fixed
> 
> >>> +       }
> >>> +
> >>> +       if (!IS_ERR(vc5->pin_clkin)) {
> >>> +               clk_prepare_enable(vc5->pin_clkin);
> > 
> > Shouldn't the input clocks be enabled only when at least one of the
> > outputs is enabled ?
> 
> Yes, I'll have to drill into this a bit.
> 
> >>> +               vc5->pin_clkin_name = __clk_get_name(vc5->pin_clkin);
> >>> +               vc5->clk_mux_ins |= BIT(1);
> >>> +       }
> >>> +
> >>> +       if (!vc5->clk_mux_ins) {
> >>> +               dev_err(&client->dev, "no input clock specified!\n");
> >>> +               return -EINVAL;
> >>> +       }
> >>> +
> >>> +       /* Register clock input mux */
> >>> +       memset(&init, 0, sizeof(init));
> >>> +       if (vc5->clk_mux_ins == (BIT(0) | BIT(1))) {
> >>> +               parent_names[0] = vc5->pin_xin_name;
> >>> +               parent_names[1] = vc5->pin_clkin_name;
> >>> +               init.num_parents = 2;
> >>> +       } else if (vc5->clk_mux_ins == BIT(0)) {
> >>> +               parent_names[0] = vc5->pin_xin_name;
> >>> +               init.num_parents = 1;
> >>> +       } else {
> >>> +               parent_names[0] = vc5->pin_clkin_name;
> >>> +               init.num_parents = 1;
> >>> +       }
> > 
> > How about
> > 
> > 	if (vc5->clk_mux_ins & BIT(0))
> > 	
> > 		parent_names[init.num_parents++] = vc5->pin_xin_name;
> > 	
> > 	if (vc5->clk_mux_ins & BIT(1))
> > 	
> > 		parent_names[init.num_parents++] = vc5->pin_clkin_name;
> > 
> > Even better, you could move this into you !IS_ERR(vc5->pin_xin) and
> > !IS_ERR(vc5->pin_clkin) checks above, and get rid of the temporary
> > pin_xin_name and pin_clkin_name fields that are only used for this
> > purpose.
> 
> That's nice indeed.
> 
> >>> +       init.name = vc5_mux_names[0];
> > 
> > I could be mistaken, but aren't clock names supposed to be unique ? If so,
> > you couldn't support multiple instances of this device.
> 
> By this device, you mean the mux or the clock chip ? In case of the
> former, if there is a VC5 with multiple muxes, the clock structure would
> need to be reworked indeed. In the later case, you access the
> device node (which is unique) and then the elements of it, which is
> again unique.

You're right, please ignore my comment.

> >>> +       init.ops = &vc5_mux_ops;
> >>> +       init.flags = 0;
> >>> +       init.parent_names = parent_names;
> >>> +       vc5->clk_mux.init = &init;
> >>> +       ret = devm_clk_hw_register(&client->dev, &vc5->clk_mux);
> >>> +       if (ret) {
> >>> +               dev_err(&client->dev, "unable to register %s\n",
> >>> init.name);
> >>> +               goto err_clk;
> >>> +       }
> >>> +
> >>> +       /* Register PLL */
> >>> +       memset(&init, 0, sizeof(init));
> >>> +       init.name = vc5_pll_names[0];
> >>> +       init.ops = &vc5_pll_ops;
> >>> +       init.flags = CLK_SET_RATE_PARENT;
> >>> +       init.parent_names = vc5_mux_names;
> >>> +       init.num_parents = 1;
> >>> +       vc5->clk_pll.num = 0;
> >>> +       vc5->clk_pll.vc5 = vc5;
> >>> +       vc5->clk_pll.hw.init = &init;
> >>> +       ret = devm_clk_hw_register(&client->dev, &vc5->clk_pll.hw);
> >>> +       if (ret) {
> >>> +               dev_err(&client->dev, "unable to register %s\n",
> >>> init.name);
> >>> +               goto err_clk;
> >>> +       }
> >>> +
> >>> +       /* Register FODs */
> >>> +       for (n = 0; n < 2; n++) {
> >>> +               memset(&init, 0, sizeof(init));
> >>> +               init.name = vc5_fod_names[n];
> >>> +               init.ops = &vc5_fod_ops;
> >>> +               init.flags = CLK_SET_RATE_PARENT;
> >>> +               init.parent_names = vc5_pll_names;
> >>> +               init.num_parents = 1;
> >>> +               vc5->clk_fod[n].num = n;
> >>> +               vc5->clk_fod[n].vc5 = vc5;
> >>> +               vc5->clk_fod[n].hw.init = &init;
> >>> +               ret = devm_clk_hw_register(&client->dev,
> >>> &vc5->clk_fod[n].hw);
> >>> +               if (ret) {
> >>> +                       dev_err(&client->dev, "unable to register %s\n",
> >>> +                               init.name);
> >>> +                       goto err_clk;
> >>> +               }
> >>> +       }
> >>> +
> >>> +       /* Register OUT1 and OUT2 */
> >>> +       for (n = 0; n < 2; n++) {
> >>> +               parent_names[0] = vc5_fod_names[n];
> >>> +               if (n == 0)
> >>> +                       parent_names[1] = vc5_mux_names[0];
> >>> +               else
> >>> +                       parent_names[1] = vc5_clk_out_names[n];
> >>> +
> >>> +               memset(&init, 0, sizeof(init));
> >>> +               init.name = vc5_clk_out_names[n + 1];
> >>> +               init.ops = &vc5_clk_out_ops;
> >>> +               init.flags = CLK_SET_RATE_PARENT;
> >>> +               init.parent_names = parent_names;
> >>> +               init.num_parents = 2;
> >>> +               vc5->clk_out[n].num = n;
> >>> +               vc5->clk_out[n].vc5 = vc5;
> >>> +               vc5->clk_out[n].hw.init = &init;
> >>> +               ret = devm_clk_hw_register(&client->dev,
> >>> +                                          &vc5->clk_out[n].hw);
> >>> +               if (ret) {
> >>> +                       dev_err(&client->dev, "unable to register %s\n",
> >>> +                               init.name);
> >>> +                       goto err_clk;
> >>> +               }
> >>> +       }
> >>> +
> >>> +       ret = of_clk_add_hw_provider(client->dev.of_node,
> >>> vc5_of_clk_get,
> >>> vc5);
> >>> +       if (ret) {
> >>> +               dev_err(&client->dev, "unable to add clk provider\n");
> >>> +               goto err_clk;
> >>> +       }
> >>> +
> >>> +       return 0;
> >>> +
> >>> +err_clk:
> >>> +       if (!IS_ERR(vc5->pin_xin))
> >>> +               clk_disable_unprepare(vc5->pin_xin);
> >>> +       if (!IS_ERR(vc5->pin_clkin))
> >>> +               clk_disable_unprepare(vc5->pin_clkin);
> >>> +       return ret;
> >>> +}

[snip]

Marek Vasut Jan. 5, 2017, 3:44 p.m. UTC | #5

On 01/05/2017 03:13 PM, Laurent Pinchart wrote:
> Hi Marek,

Hi!

[...]

>>>>> +static unsigned long vc5_mux_recalc_rate(struct clk_hw *hw,
>>>>> +                                        unsigned long parent_rate)
>>>>> +{
>>>>> +       struct vc5_driver_data *vc5 =
>>>>> +               container_of(hw, struct vc5_driver_data, clk_mux);
>>>>> +       unsigned long idiv;
>>>>> +       u8 div;
>>>>> +
>>>>> +       /* FIXME: Needs locking ? */
>>>
>>> Let's fix it then :-)
>>
>> I would like to get feedback on this one, does it ?
> 
> That's a question for Mike or Stephen I believe.

OK

>>>>> +       /* CLKIN within range of PLL input, feed directly to PLL. */
>>>>> +       if (parent_rate <= 50000000) {
>>>>> +               regmap_update_bits(vc5->regmap, VC5_VCO_CTRL_AND_PREDIV,
>>>>> +                                 
>>>>> VC5_VCO_CTRL_AND_PREDIV_BYPASS_PREDIV,
>>>>> +                                 
>>>>> VC5_VCO_CTRL_AND_PREDIV_BYPASS_PREDIV);
>>>>> +               regmap_update_bits(vc5->regmap, VC5_REF_DIVIDER, 0xff,
>>>>> 0x00);
>>>>> +               return parent_rate;
>>>>> +       }
>>>>> +
>>>>> +       idiv = DIV_ROUND_UP(parent_rate, 50000000);
>>>>> +       if (idiv > 127)
>>>>> +               return -EINVAL;
>>>>> +
>>>>> +       /* We have dedicated div-2 predivider. */
>>>>> +       if (idiv == 2)
>>>>> +               div = VC5_REF_DIVIDER_SEL_PREDIV2;
>>>>> +       else
>>>>> +               div = VC5_REF_DIVIDER_REF_DIV(idiv);
>>>>> +
>>>>> +       regmap_update_bits(vc5->regmap, VC5_REF_DIVIDER, 0xff, div);
>>>>> +       regmap_update_bits(vc5->regmap, VC5_VCO_CTRL_AND_PREDIV,
>>>>> +                          VC5_VCO_CTRL_AND_PREDIV_BYPASS_PREDIV, 0);
>>>>> +
>>>>> +       return parent_rate / idiv;
>>>>> +}
> 
> [snip]
> 
>>>>> +static int vc5_clk_out_set_parent(struct clk_hw *hw, u8 index)
>>>>> +{
>>>>> +       struct vc5_hw_data *hwdata = container_of(hw, struct
>>>>> vc5_hw_data, hw);
>>>>> +       struct vc5_driver_data *vc5 = hwdata->vc5;
>>>>> +       const u8 mask = VC5_OUT_DIV_CONTROL_RESET |
>>>>> +                       VC5_OUT_DIV_CONTROL_SELB_NORM |
>>>>> +                       VC5_OUT_DIV_CONTROL_SEL_EXT |
>>>>> +                       VC5_OUT_DIV_CONTROL_EN_FOD;
>>>>> +       const u8 extclk = VC5_OUT_DIV_CONTROL_SELB_NORM |
>>>>> +                         VC5_OUT_DIV_CONTROL_SEL_EXT;
>>>>> +       u8 src = VC5_OUT_DIV_CONTROL_RESET;
>>>>> +
>>>>> +       if (index == 0)
>>>>> +               src |= VC5_OUT_DIV_CONTROL_EN_FOD;
>>>>> +       else if (index == 1)
>>>>> +               src |= extclk;
>>>>> +       else
>>>>> +               return -EINVAL;
>>>
>>> Can this happen given that the number of parents is set to 2 ?
>>
>> I believe it should not happen, but I'd rather sanitize the input here
>> to be safe. Shall I remove it ?
> 
> I'd remove it as it can't happen. Being called with index > 1 would be similar 
> to being called with hw == NULL, which you don't check explicitly. I don't 
> think we should sanitize every input parameter value in every driver when the 
> core is supposed to take care of that.

Dropped

The rest is done and I'll sort out the remaining bits (pm, gating) and
repost once I receive the kit.

Stephen Boyd Jan. 10, 2017, 12:23 a.m. UTC | #6

On 01/05, Marek Vasut wrote:
> On 01/05/2017 03:13 PM, Laurent Pinchart wrote:
> > Hi Marek,
> 
> Hi!
> 
> [...]
> 
> >>>>> +static unsigned long vc5_mux_recalc_rate(struct clk_hw *hw,
> >>>>> +                                        unsigned long parent_rate)
> >>>>> +{
> >>>>> +       struct vc5_driver_data *vc5 =
> >>>>> +               container_of(hw, struct vc5_driver_data, clk_mux);
> >>>>> +       unsigned long idiv;
> >>>>> +       u8 div;
> >>>>> +
> >>>>> +       /* FIXME: Needs locking ? */
> >>>
> >>> Let's fix it then :-)
> >>
> >> I would like to get feedback on this one, does it ?
> > 
> > That's a question for Mike or Stephen I believe.
> 
> OK

What's the question?

Marek Vasut Jan. 10, 2017, 12:29 a.m. UTC | #7

On 01/10/2017 01:23 AM, Stephen Boyd wrote:
> On 01/05, Marek Vasut wrote:
>> On 01/05/2017 03:13 PM, Laurent Pinchart wrote:
>>> Hi Marek,
>>
>> Hi!
>>
>> [...]
>>
>>>>>>> +static unsigned long vc5_mux_recalc_rate(struct clk_hw *hw,
>>>>>>> +                                        unsigned long parent_rate)
>>>>>>> +{
>>>>>>> +       struct vc5_driver_data *vc5 =
>>>>>>> +               container_of(hw, struct vc5_driver_data, clk_mux);
>>>>>>> +       unsigned long idiv;
>>>>>>> +       u8 div;
>>>>>>> +
>>>>>>> +       /* FIXME: Needs locking ? */
>>>>>
>>>>> Let's fix it then :-)
>>>>
>>>> I would like to get feedback on this one, does it ?
>>>
>>> That's a question for Mike or Stephen I believe.
>>
>> OK
> 
> What's the question?

Whether or not I need a lock around the code in vc5_mux_recalc_rate(),
since I am also tweaking the predivider bits there to assure the
(downstream) PLL supplied from the mux always gets clock in range it can
handle. This tweaking is mostly inspired by clk-si5351.c driver.

Stephen Boyd Jan. 10, 2017, 12:44 a.m. UTC | #8

On 01/10, Marek Vasut wrote:
> On 01/10/2017 01:23 AM, Stephen Boyd wrote:
> > On 01/05, Marek Vasut wrote:
> >> On 01/05/2017 03:13 PM, Laurent Pinchart wrote:
> >>> Hi Marek,
> >>
> >> Hi!
> >>
> >> [...]
> >>
> >>>>>>> +static unsigned long vc5_mux_recalc_rate(struct clk_hw *hw,
> >>>>>>> +                                        unsigned long parent_rate)
> >>>>>>> +{
> >>>>>>> +       struct vc5_driver_data *vc5 =
> >>>>>>> +               container_of(hw, struct vc5_driver_data, clk_mux);
> >>>>>>> +       unsigned long idiv;
> >>>>>>> +       u8 div;
> >>>>>>> +
> >>>>>>> +       /* FIXME: Needs locking ? */
> >>>>>
> >>>>> Let's fix it then :-)
> >>>>
> >>>> I would like to get feedback on this one, does it ?
> >>>
> >>> That's a question for Mike or Stephen I believe.
> >>
> >> OK
> > 
> > What's the question?
> 
> Whether or not I need a lock around the code in vc5_mux_recalc_rate(),
> since I am also tweaking the predivider bits there to assure the
> (downstream) PLL supplied from the mux always gets clock in range it can
> handle. This tweaking is mostly inspired by clk-si5351.c driver.

Don't rely on locking in the core for register locking within a
device. That makes a dependency headache if we want to rework the
locking scheme in the core, which we want to do eventually.

Also, please don't cause side effects during recalc_rate(). The
callback is meant to calculate the rate of the clock, not adjust
hardware based on what arguments are passed to it.

Marek Vasut Jan. 10, 2017, 5:42 p.m. UTC | #9

On 01/10/2017 01:44 AM, Stephen Boyd wrote:
> On 01/10, Marek Vasut wrote:
>> On 01/10/2017 01:23 AM, Stephen Boyd wrote:
>>> On 01/05, Marek Vasut wrote:
>>>> On 01/05/2017 03:13 PM, Laurent Pinchart wrote:
>>>>> Hi Marek,
>>>>
>>>> Hi!
>>>>
>>>> [...]
>>>>
>>>>>>>>> +static unsigned long vc5_mux_recalc_rate(struct clk_hw *hw,
>>>>>>>>> +                                        unsigned long parent_rate)
>>>>>>>>> +{
>>>>>>>>> +       struct vc5_driver_data *vc5 =
>>>>>>>>> +               container_of(hw, struct vc5_driver_data, clk_mux);
>>>>>>>>> +       unsigned long idiv;
>>>>>>>>> +       u8 div;
>>>>>>>>> +
>>>>>>>>> +       /* FIXME: Needs locking ? */
>>>>>>>
>>>>>>> Let's fix it then :-)
>>>>>>
>>>>>> I would like to get feedback on this one, does it ?
>>>>>
>>>>> That's a question for Mike or Stephen I believe.
>>>>
>>>> OK
>>>
>>> What's the question?
>>
>> Whether or not I need a lock around the code in vc5_mux_recalc_rate(),
>> since I am also tweaking the predivider bits there to assure the
>> (downstream) PLL supplied from the mux always gets clock in range it can
>> handle. This tweaking is mostly inspired by clk-si5351.c driver.
> 
> Don't rely on locking in the core for register locking within a
> device. That makes a dependency headache if we want to rework the
> locking scheme in the core, which we want to do eventually.
> 
> Also, please don't cause side effects during recalc_rate(). The
> callback is meant to calculate the rate of the clock, not adjust
> hardware based on what arguments are passed to it.

Got it and fixed. I'll send V3 now.

clk: vc5: Add support for IDT VersaClock 5P49V5923B

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