[v5] clk: add CS2000 Fractional-N driver

Commit Message

Kuninori Morimoto Oct. 20, 2015, 1:26 a.m. UTC

From: Kuninori Morimoto <[e-mail]>

This patch adds CS2000 Fractional-N driver as clock provider.

Signed-off-by: Kuninori Morimoto <[e-mail]>
---
v4 -> v5

 - remove "clock-frequency"
 - use dev on clk_register()
 - remove CLK_IS_BASIC
 - .enable -> .prepare since it is using I2C
 . .disabe -> .unprepare since it is using I2C

 .../devicetree/bindings/clock/cs2000-cp.txt        |  22 +
 drivers/clk/Kconfig                                |   6 +
 drivers/clk/Makefile                               |   1 +
 drivers/clk/clk-cs2000-cp.c                        | 510 +++++++++++++++++++++
 4 files changed, 539 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/clock/cs2000-cp.txt
 create mode 100644 drivers/clk/clk-cs2000-cp.c

Comments

Kuninori Morimoto Oct. 30, 2015, 2:31 a.m. UTC | #1

Hi

ping ?

[R] ?? wrote:
> 
> From: Kuninori Morimoto <[e-mail]>
> 
> This patch adds CS2000 Fractional-N driver as clock provider.
> 
> Signed-off-by: Kuninori Morimoto <[e-mail]>
> ---
> v4 -> v5
> 
>  - remove "clock-frequency"
>  - use dev on clk_register()
>  - remove CLK_IS_BASIC
>  - .enable -> .prepare since it is using I2C
>  . .disabe -> .unprepare since it is using I2C
> 
>  .../devicetree/bindings/clock/cs2000-cp.txt        |  22 +
>  drivers/clk/Kconfig                                |   6 +
>  drivers/clk/Makefile                               |   1 +
>  drivers/clk/clk-cs2000-cp.c                        | 510 +++++++++++++++++++++
>  4 files changed, 539 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/clock/cs2000-cp.txt
>  create mode 100644 drivers/clk/clk-cs2000-cp.c
> 
> diff --git a/Documentation/devicetree/bindings/clock/cs2000-cp.txt b/Documentation/devicetree/bindings/clock/cs2000-cp.txt
> new file mode 100644
> index 0000000..54e6df0
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/clock/cs2000-cp.txt
> @@ -0,0 +1,22 @@
> +CIRRUS LOGIC Fractional-N Clock Synthesizer & Clock Multiplier
> +
> +Required properties:
> +
> +- compatible:		"cirrus,cs2000-cp"
> +- reg:			The chip select number on the I2C bus
> +- clocks:		common clock binding for CLK_IN, XTI/REF_CLK
> +- clock-names:		CLK_IN : clk_in, XTI/REF_CLK : ref_clk
> +- #clock-cells:		must be <0>
> +
> +Example:
> +
> +&i2c2 {
> +	...
> +	cs2000: clk_multiplier@4f {
> +		#clock-cells = <0>;
> +		compatible = "cirrus,cs2000-cp";
> +		reg = <0x4f>;
> +		clocks = <&rcar_sound 0>, <&x12_clk>;
> +		clock-names = "clk_in", "ref_clk";
> +	};
> +};
> diff --git a/drivers/clk/Kconfig b/drivers/clk/Kconfig
> index 42f7120..0e961b2 100644
> --- a/drivers/clk/Kconfig
> +++ b/drivers/clk/Kconfig
> @@ -95,6 +95,12 @@ config COMMON_CLK_CDCE925
>  	  Given a target output frequency, the driver will set the PLL and
>  	  divider to best approximate the desired output.
>  
> +config COMMON_CLK_CS2000_CP
> +	tristate "Clock driver for CS2000 Fractional-N Clock Synthesizer & Clock Multiplier"
> +	depends on I2C
> +	help
> +	  If you say yes here you get support for the CS2000 clock multiplier.
> +
>  config COMMON_CLK_S2MPS11
>  	tristate "Clock driver for S2MPS1X/S5M8767 MFD"
>  	depends on MFD_SEC_CORE
> diff --git a/drivers/clk/Makefile b/drivers/clk/Makefile
> index 9d31e2c..2fb77a8 100644
> --- a/drivers/clk/Makefile
> +++ b/drivers/clk/Makefile
> @@ -21,6 +21,7 @@ obj-$(CONFIG_COMMON_CLK_AXI_CLKGEN)	+= clk-axi-clkgen.o
>  obj-$(CONFIG_ARCH_AXXIA)		+= clk-axm5516.o
>  obj-$(CONFIG_ARCH_BCM2835)		+= clk-bcm2835.o
>  obj-$(CONFIG_COMMON_CLK_CDCE706)	+= clk-cdce706.o
> +obj-$(CONFIG_COMMON_CLK_CS2000_CP)	+= clk-cs2000-cp.o
>  obj-$(CONFIG_ARCH_CLPS711X)		+= clk-clps711x.o
>  obj-$(CONFIG_ARCH_EFM32)		+= clk-efm32gg.o
>  obj-$(CONFIG_ARCH_HIGHBANK)		+= clk-highbank.o
> diff --git a/drivers/clk/clk-cs2000-cp.c b/drivers/clk/clk-cs2000-cp.c
> new file mode 100644
> index 0000000..71d9340
> --- /dev/null
> +++ b/drivers/clk/clk-cs2000-cp.c
> @@ -0,0 +1,510 @@
> +/*
> + * CS2000  --  CIRRUS LOGIC Fractional-N Clock Synthesizer & Clock Multiplier
> + *
> + * Copyright (C) 2015 Renesas Electronics Corporation
> + * Kuninori Morimoto <[e-mail]>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + */
> +#include <linux/clk-provider.h>
> +#include <linux/delay.h>
> +#include <linux/clk.h>
> +#include <linux/i2c.h>
> +#include <linux/of_device.h>
> +#include <linux/module.h>
> +
> +#define CH_MAX 4
> +
> +#define DEVICE_ID	0x1
> +#define DEVICE_CTRL	0x2
> +#define DEVICE_CFG1	0x3
> +#define DEVICE_CFG2	0x4
> +#define GLOBAL_CFG	0x5
> +#define Ratio_Add(x, nth)	(6 + (x * 4) + (nth))
> +#define Ratio_Val(x, nth)	((x >> (24 - (8 * nth))) & 0xFF)
> +#define Val_Ratio(x, nth)	((x & 0xFF) << (24 - (8 * nth)))
> +#define FUNC_CFG1	0x16
> +#define FUNC_CFG2	0x17
> +
> +/* DEVICE_CTRL */
> +#define PLL_UNLOCK	(1 << 7)
> +
> +/* DEVICE_CFG1 */
> +#define RSEL(x)		(((x) & 0x3) << 3)
> +#define RSEL_MASK	RSEL(0x3)
> +#define ENDEV1		(0x1)
> +
> +/* GLOBAL_CFG */
> +#define ENDEV2		(0x1)
> +
> +#define CH_SIZE_ERR(ch)		((ch < 0) || (ch >= CH_MAX))
> +#define hw_to_priv(_hw)		container_of(_hw, struct cs2000_priv, hw)
> +#define priv_to_client(priv)	(priv->client)
> +#define priv_to_dev(priv)	(&(priv_to_client(priv)->dev))
> +
> +#define CLK_IN	0
> +#define REF_CLK	1
> +#define CLK_MAX 2
> +
> +struct cs2000_priv {
> +	struct clk_hw hw;
> +	struct i2c_client *client;
> +	struct clk *clk_in;
> +	struct clk *ref_clk;
> +	struct clk *clk_out;
> +};
> +
> +static const struct of_device_id cs2000_of_match[] = {
> +	{ .compatible = "cirrus,cs2000-cp", },
> +	{},
> +};
> +MODULE_DEVICE_TABLE(of, cs2000_of_match);
> +
> +static const struct i2c_device_id cs2000_id[] = {
> +	{ "cs2000-cp", },
> +	{}
> +};
> +MODULE_DEVICE_TABLE(i2c, cs2000_id);
> +
> +#define cs2000_read(priv, addr) \
> +	i2c_smbus_read_byte_data(priv_to_client(priv), addr)
> +#define cs2000_write(priv, addr, val) \
> +	i2c_smbus_write_byte_data(priv_to_client(priv), addr, val)
> +
> +static int cs2000_bset(struct cs2000_priv *priv, u8 addr, u8 mask, u8 val)
> +{
> +	s32 data;
> +
> +	data = cs2000_read(priv, addr);
> +	if (data < 0)
> +		return data;
> +
> +	data &= ~mask;
> +	data |= (val & mask);
> +
> +	return cs2000_write(priv, addr, data);
> +}
> +
> +static int cs2000_enable_dev_config(struct cs2000_priv *priv, bool enable)
> +{
> +	u32 val;
> +	int ret;
> +
> +	val = enable ? ENDEV1 : 0;
> +	ret = cs2000_bset(priv, DEVICE_CFG1, ENDEV1, val);
> +	if (ret < 0)
> +		return ret;
> +
> +	val = enable ? ENDEV2 : 0;
> +	ret = cs2000_bset(priv, GLOBAL_CFG,  ENDEV2, val);
> +	if (ret < 0)
> +		return ret;
> +
> +	return 0;
> +}
> +
> +static int cs2000_clk_in_bound_rate(struct cs2000_priv *priv,
> +				    u32 rate_in)
> +{
> +	u32 val;
> +
> +	if (rate_in >= 32000000 &&
> +	    rate_in < 56000000)
> +		val = 0x0;
> +	else if (rate_in >= 16000000 &&
> +		 rate_in < 28000000)
> +		val = 0x1;
> +	else if (rate_in >= 8000000 &&
> +		 rate_in < 14000000)
> +		val = 0x2;
> +	else
> +		return -EINVAL;
> +
> +	return cs2000_bset(priv, FUNC_CFG1, 0x3 << 3, val << 3);
> +}
> +
> +static int cs2000_wait_pll_lock(struct cs2000_priv *priv)
> +{
> +	struct device *dev = priv_to_dev(priv);
> +	s32 val;
> +	unsigned int i;
> +
> +	for (i = 0; i < 256; i++) {
> +		val = cs2000_read(priv, DEVICE_CTRL);
> +		if (val < 0)
> +			return val;
> +		if (!(val & PLL_UNLOCK))
> +			return 0;
> +		udelay(1);
> +	}
> +
> +	dev_err(dev, "pll lock failed\n");
> +
> +	return -EIO;
> +}
> +
> +static int cs2000_clk_out_enable(struct cs2000_priv *priv, bool enable)
> +{
> +	u32 val = enable ? 0 : 0x3;
> +
> +	/* enable both AUX_OUT, CLK_OUT */
> +	return cs2000_write(priv, DEVICE_CTRL, val);
> +}
> +
> +static u32 cs2000_rate_to_ratio(u32 rate_in, u32 rate_out)
> +{
> +	u64 ratio;
> +
> +	/*
> +	 * ratio = rate_out / rate_in * 2^20
> +	 *
> +	 * To avoid over flow, rate_out is u64
> +	 * The result should be u32
> +	 */
> +	ratio = (u64)rate_out << 20;
> +	do_div(ratio, rate_in);
> +
> +	return (u32)ratio;
> +}
> +
> +static unsigned long cs2000_ratio_to_rate(u32 ratio, u32 rate_in)
> +{
> +	u64 rate_out;
> +
> +	/*
> +	 * ratio = rate_out / rate_in * 2^20
> +	 *
> +	 * To avoid over flow, rate_out is u64
> +	 * The result should be u32
> +	 */
> +
> +	rate_out = (u64)ratio * rate_in;
> +	return (unsigned long)(rate_out >> 20);
> +}
> +
> +static int cs2000_ratio_set(struct cs2000_priv *priv,
> +			    int ch, u32 rate_in, u32 rate_out)
> +{
> +	u32 val;
> +	unsigned int i;
> +	int ret;
> +
> +	if (CH_SIZE_ERR(ch))
> +		return -EINVAL;
> +
> +	val = cs2000_rate_to_ratio(rate_in, rate_out);
> +	for (i = 0; i < 4; i++) {
> +		ret = cs2000_write(priv,
> +				   Ratio_Add(ch, i),
> +				   Ratio_Val(val, i));
> +		if (ret < 0)
> +			return ret;
> +	}
> +
> +	return 0;
> +}
> +
> +static u32 cs2000_ratio_get(struct cs2000_priv *priv, int ch)
> +{
> +	u32 tmp, val;
> +	unsigned int i;
> +
> +	val = 0;
> +	for (i = 0; i < 4; i++) {
> +		tmp = cs2000_read(priv,
> +				  Ratio_Add(ch, i));
> +		if (tmp < 0)
> +			return 0;
> +
> +		val |= Val_Ratio(tmp, i);
> +	}
> +
> +	return val;
> +}
> +
> +static int cs2000_ratio_select(struct cs2000_priv *priv, int ch)
> +{
> +	int ret;
> +
> +	if (CH_SIZE_ERR(ch))
> +		return -EINVAL;
> +
> +	/*
> +	 * FIXME
> +	 *
> +	 * this driver supports static ratio mode only
> +	 * at this point
> +	 */
> +	ret = cs2000_bset(priv, DEVICE_CFG1, RSEL_MASK, RSEL(ch));
> +	if (ret < 0)
> +		return ret;
> +
> +	ret = cs2000_write(priv, DEVICE_CFG2, 0x0);
> +	if (ret < 0)
> +		return ret;
> +
> +	return 0;
> +}
> +
> +static unsigned long cs2000_recalc_rate(struct clk_hw *hw,
> +					unsigned long parent_rate)
> +{
> +	struct cs2000_priv *priv = hw_to_priv(hw);
> +	int ch = 0; /* it uses ch0 only at this point */
> +	u32 ratio;
> +
> +	ratio = cs2000_ratio_get(priv, ch);
> +
> +	return cs2000_ratio_to_rate(ratio, parent_rate);
> +}
> +
> +static long cs2000_round_rate(struct clk_hw *hw, unsigned long rate,
> +			      unsigned long *parent_rate)
> +{
> +	u32 ratio;
> +
> +	ratio = cs2000_rate_to_ratio(*parent_rate, rate);
> +
> +	return cs2000_ratio_to_rate(ratio, *parent_rate);
> +}
> +
> +static int __cs2000_set_rate(struct cs2000_priv *priv, int ch,
> +			     unsigned long rate, unsigned long parent_rate)
> +
> +{
> +	int ret;
> +
> +	ret = cs2000_clk_in_bound_rate(priv, parent_rate);
> +	if (ret < 0)
> +		return ret;
> +
> +	ret = cs2000_ratio_set(priv, ch, parent_rate, rate);
> +	if (ret < 0)
> +		return ret;
> +
> +	ret = cs2000_ratio_select(priv, ch);
> +	if (ret < 0)
> +		return ret;
> +
> +	return 0;
> +}
> +
> +static int cs2000_set_rate(struct clk_hw *hw,
> +			   unsigned long rate, unsigned long parent_rate)
> +{
> +	struct cs2000_priv *priv = hw_to_priv(hw);
> +	int ch = 0; /* it uses ch0 only at this point */
> +
> +	return __cs2000_set_rate(priv, ch, rate, parent_rate);
> +}
> +
> +static int cs2000_enable(struct clk_hw *hw)
> +{
> +	struct cs2000_priv *priv = hw_to_priv(hw);
> +	int ret;
> +
> +	ret = cs2000_enable_dev_config(priv, true);
> +	if (ret < 0)
> +		return ret;
> +
> +	ret = cs2000_clk_out_enable(priv, true);
> +	if (ret < 0)
> +		return ret;
> +
> +	ret = cs2000_wait_pll_lock(priv);
> +	if (ret < 0)
> +		return ret;
> +
> +	return ret;
> +}
> +
> +static void cs2000_disable(struct clk_hw *hw)
> +{
> +	struct cs2000_priv *priv = hw_to_priv(hw);
> +
> +	cs2000_enable_dev_config(priv, false);
> +
> +	cs2000_clk_out_enable(priv, false);
> +}
> +
> +static u8 cs2000_get_parent(struct clk_hw *hw)
> +{
> +	/* always return REF_CLK */
> +	return REF_CLK;
> +}
> +
> +static const struct clk_ops cs2000_ops = {
> +	.get_parent	= cs2000_get_parent,
> +	.recalc_rate	= cs2000_recalc_rate,
> +	.round_rate	= cs2000_round_rate,
> +	.set_rate	= cs2000_set_rate,
> +	.prepare	= cs2000_enable,
> +	.unprepare	= cs2000_disable,
> +};
> +
> +static int cs2000_clk_get(struct cs2000_priv *priv)
> +{
> +	struct i2c_client *client = priv_to_client(priv);
> +	struct device *dev = &client->dev;
> +	struct clk *clk_in, *ref_clk;
> +
> +	clk_in = devm_clk_get(dev, "clk_in");
> +	/* not yet provided */
> +	if (IS_ERR(clk_in))
> +		return -EPROBE_DEFER;
> +
> +	ref_clk = devm_clk_get(dev, "ref_clk");
> +	/* not yet provided */
> +	if (IS_ERR(ref_clk))
> +		return -EPROBE_DEFER;
> +
> +	priv->clk_in	= clk_in;
> +	priv->ref_clk	= ref_clk;
> +
> +	return 0;
> +}
> +
> +static int cs2000_clk_register(struct cs2000_priv *priv)
> +{
> +	struct device *dev = priv_to_dev(priv);
> +	struct device_node *np = dev->of_node;
> +	struct clk_init_data init;
> +	const char *name = np->name;
> +	struct clk *clk;
> +	static const char *parent_names[CLK_MAX];
> +	int ch = 0; /* it uses ch0 only at this point */
> +	int rate;
> +	int ret;
> +
> +	of_property_read_string(np, "clock-output-names", &name);
> +
> +	/*
> +	 * set default rate as 1/1.
> +	 * otherwise .set_rate which setup ratio
> +	 * is never called if user requests 1/1 rate
> +	 */
> +	rate = clk_get_rate(priv->ref_clk);
> +	ret = __cs2000_set_rate(priv, ch, rate, rate);
> +	if (ret < 0)
> +		return ret;
> +
> +	parent_names[CLK_IN]	= __clk_get_name(priv->clk_in);
> +	parent_names[REF_CLK]	= __clk_get_name(priv->ref_clk);
> +
> +	init.name		= name;
> +	init.ops		= &cs2000_ops;
> +	init.flags		= CLK_SET_RATE_GATE;
> +	init.parent_names	= parent_names;
> +	init.num_parents	= ARRAY_SIZE(parent_names);
> +
> +	priv->hw.init = &init;
> +
> +	clk = clk_register(dev, &priv->hw);
> +	if (IS_ERR(clk))
> +		return PTR_ERR(clk);
> +
> +	ret = of_clk_add_provider(np, of_clk_src_simple_get, clk);
> +	if (ret < 0) {
> +		clk_unregister(clk);
> +		return ret;
> +	}
> +
> +	priv->clk_out = clk;
> +
> +	return 0;
> +}
> +
> +static int cs2000_version_print(struct cs2000_priv *priv)
> +{
> +	struct i2c_client *client = priv_to_client(priv);
> +	struct device *dev = &client->dev;
> +	s32 val = cs2000_read(priv, DEVICE_ID);
> +	const char *revision;
> +
> +	if (val < 0)
> +		return val;
> +
> +	/* CS2000 should be 0x0 */
> +	if (0 != (val >> 3))
> +		return -EIO;
> +
> +	switch (val & 0x7) {
> +	case 0x4:
> +		revision = "B2 / B3";
> +		break;
> +	case 0x6:
> +		revision = "C1";
> +		break;
> +	default:
> +		return -EIO;
> +	}
> +
> +	dev_info(dev, "revision - %s\n", revision);
> +
> +	return 0;
> +}
> +
> +static int cs2000_remove(struct i2c_client *client)
> +{
> +	struct cs2000_priv *priv = i2c_get_clientdata(client);
> +	struct device *dev = &client->dev;
> +	struct device_node *np = dev->of_node;
> +
> +	of_clk_del_provider(np);
> +
> +	clk_unregister(priv->clk_out);
> +
> +	return 0;
> +}
> +
> +static int cs2000_probe(struct i2c_client *client,
> +			const struct i2c_device_id *id)
> +{
> +	struct cs2000_priv *priv;
> +	struct device *dev = &client->dev;
> +	int ret;
> +
> +	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
> +	if (!priv)
> +		return -ENOMEM;
> +
> +	priv->client = client;
> +	i2c_set_clientdata(client, priv);
> +
> +	ret = cs2000_clk_get(priv);
> +	if (ret < 0)
> +		return ret;
> +
> +	ret = cs2000_clk_register(priv);
> +	if (ret < 0)
> +		return ret;
> +
> +	ret = cs2000_version_print(priv);
> +	if (ret < 0)
> +		goto probe_err;
> +
> +	return 0;
> +
> +probe_err:
> +	cs2000_remove(client);
> +
> +	return ret;
> +}
> +
> +static struct i2c_driver cs2000_driver = {
> +	.driver = {
> +		.name = "cs2000-cp",
> +		.of_match_table = cs2000_of_match,
> +	},
> +	.probe		= cs2000_probe,
> +	.remove		= cs2000_remove,
> +	.id_table	= cs2000_id,
> +};
> +
> +module_i2c_driver(cs2000_driver);
> +
> +MODULE_DESCRIPTION("CS2000-CP driver");
> +MODULE_AUTHOR("Kuninori Morimoto <[e-mail]>");
> +MODULE_LICENSE("GPL v2");
> -- 
> 1.9.1
> 
> --
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Best regards
---
Kuninori Morimoto
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Kuninori Morimoto Nov. 6, 2015, 6:42 a.m. UTC | #2

Hi again

ping again ?

> [R] ?? wrote:
> > 
> > From: Kuninori Morimoto <[e-mail]>
> > 
> > This patch adds CS2000 Fractional-N driver as clock provider.
> > 
> > Signed-off-by: Kuninori Morimoto <[e-mail]>
> > ---
> > v4 -> v5
> > 
> >  - remove "clock-frequency"
> >  - use dev on clk_register()
> >  - remove CLK_IS_BASIC
> >  - .enable -> .prepare since it is using I2C
> >  . .disabe -> .unprepare since it is using I2C
> > 
> >  .../devicetree/bindings/clock/cs2000-cp.txt        |  22 +
> >  drivers/clk/Kconfig                                |   6 +
> >  drivers/clk/Makefile                               |   1 +
> >  drivers/clk/clk-cs2000-cp.c                        | 510 +++++++++++++++++++++
> >  4 files changed, 539 insertions(+)
> >  create mode 100644 Documentation/devicetree/bindings/clock/cs2000-cp.txt
> >  create mode 100644 drivers/clk/clk-cs2000-cp.c
> > 
> > diff --git a/Documentation/devicetree/bindings/clock/cs2000-cp.txt b/Documentation/devicetree/bindings/clock/cs2000-cp.txt
> > new file mode 100644
> > index 0000000..54e6df0
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/clock/cs2000-cp.txt
> > @@ -0,0 +1,22 @@
> > +CIRRUS LOGIC Fractional-N Clock Synthesizer & Clock Multiplier
> > +
> > +Required properties:
> > +
> > +- compatible:		"cirrus,cs2000-cp"
> > +- reg:			The chip select number on the I2C bus
> > +- clocks:		common clock binding for CLK_IN, XTI/REF_CLK
> > +- clock-names:		CLK_IN : clk_in, XTI/REF_CLK : ref_clk
> > +- #clock-cells:		must be <0>
> > +
> > +Example:
> > +
> > +&i2c2 {
> > +	...
> > +	cs2000: clk_multiplier@4f {
> > +		#clock-cells = <0>;
> > +		compatible = "cirrus,cs2000-cp";
> > +		reg = <0x4f>;
> > +		clocks = <&rcar_sound 0>, <&x12_clk>;
> > +		clock-names = "clk_in", "ref_clk";
> > +	};
> > +};
> > diff --git a/drivers/clk/Kconfig b/drivers/clk/Kconfig
> > index 42f7120..0e961b2 100644
> > --- a/drivers/clk/Kconfig
> > +++ b/drivers/clk/Kconfig
> > @@ -95,6 +95,12 @@ config COMMON_CLK_CDCE925
> >  	  Given a target output frequency, the driver will set the PLL and
> >  	  divider to best approximate the desired output.
> >  
> > +config COMMON_CLK_CS2000_CP
> > +	tristate "Clock driver for CS2000 Fractional-N Clock Synthesizer & Clock Multiplier"
> > +	depends on I2C
> > +	help
> > +	  If you say yes here you get support for the CS2000 clock multiplier.
> > +
> >  config COMMON_CLK_S2MPS11
> >  	tristate "Clock driver for S2MPS1X/S5M8767 MFD"
> >  	depends on MFD_SEC_CORE
> > diff --git a/drivers/clk/Makefile b/drivers/clk/Makefile
> > index 9d31e2c..2fb77a8 100644
> > --- a/drivers/clk/Makefile
> > +++ b/drivers/clk/Makefile
> > @@ -21,6 +21,7 @@ obj-$(CONFIG_COMMON_CLK_AXI_CLKGEN)	+= clk-axi-clkgen.o
> >  obj-$(CONFIG_ARCH_AXXIA)		+= clk-axm5516.o
> >  obj-$(CONFIG_ARCH_BCM2835)		+= clk-bcm2835.o
> >  obj-$(CONFIG_COMMON_CLK_CDCE706)	+= clk-cdce706.o
> > +obj-$(CONFIG_COMMON_CLK_CS2000_CP)	+= clk-cs2000-cp.o
> >  obj-$(CONFIG_ARCH_CLPS711X)		+= clk-clps711x.o
> >  obj-$(CONFIG_ARCH_EFM32)		+= clk-efm32gg.o
> >  obj-$(CONFIG_ARCH_HIGHBANK)		+= clk-highbank.o
> > diff --git a/drivers/clk/clk-cs2000-cp.c b/drivers/clk/clk-cs2000-cp.c
> > new file mode 100644
> > index 0000000..71d9340
> > --- /dev/null
> > +++ b/drivers/clk/clk-cs2000-cp.c
> > @@ -0,0 +1,510 @@
> > +/*
> > + * CS2000  --  CIRRUS LOGIC Fractional-N Clock Synthesizer & Clock Multiplier
> > + *
> > + * Copyright (C) 2015 Renesas Electronics Corporation
> > + * Kuninori Morimoto <[e-mail]>
> > + *
> > + * This program is free software; you can redistribute it and/or modify
> > + * it under the terms of the GNU General Public License version 2 as
> > + * published by the Free Software Foundation.
> > + */
> > +#include <linux/clk-provider.h>
> > +#include <linux/delay.h>
> > +#include <linux/clk.h>
> > +#include <linux/i2c.h>
> > +#include <linux/of_device.h>
> > +#include <linux/module.h>
> > +
> > +#define CH_MAX 4
> > +
> > +#define DEVICE_ID	0x1
> > +#define DEVICE_CTRL	0x2
> > +#define DEVICE_CFG1	0x3
> > +#define DEVICE_CFG2	0x4
> > +#define GLOBAL_CFG	0x5
> > +#define Ratio_Add(x, nth)	(6 + (x * 4) + (nth))
> > +#define Ratio_Val(x, nth)	((x >> (24 - (8 * nth))) & 0xFF)
> > +#define Val_Ratio(x, nth)	((x & 0xFF) << (24 - (8 * nth)))
> > +#define FUNC_CFG1	0x16
> > +#define FUNC_CFG2	0x17
> > +
> > +/* DEVICE_CTRL */
> > +#define PLL_UNLOCK	(1 << 7)
> > +
> > +/* DEVICE_CFG1 */
> > +#define RSEL(x)		(((x) & 0x3) << 3)
> > +#define RSEL_MASK	RSEL(0x3)
> > +#define ENDEV1		(0x1)
> > +
> > +/* GLOBAL_CFG */
> > +#define ENDEV2		(0x1)
> > +
> > +#define CH_SIZE_ERR(ch)		((ch < 0) || (ch >= CH_MAX))
> > +#define hw_to_priv(_hw)		container_of(_hw, struct cs2000_priv, hw)
> > +#define priv_to_client(priv)	(priv->client)
> > +#define priv_to_dev(priv)	(&(priv_to_client(priv)->dev))
> > +
> > +#define CLK_IN	0
> > +#define REF_CLK	1
> > +#define CLK_MAX 2
> > +
> > +struct cs2000_priv {
> > +	struct clk_hw hw;
> > +	struct i2c_client *client;
> > +	struct clk *clk_in;
> > +	struct clk *ref_clk;
> > +	struct clk *clk_out;
> > +};
> > +
> > +static const struct of_device_id cs2000_of_match[] = {
> > +	{ .compatible = "cirrus,cs2000-cp", },
> > +	{},
> > +};
> > +MODULE_DEVICE_TABLE(of, cs2000_of_match);
> > +
> > +static const struct i2c_device_id cs2000_id[] = {
> > +	{ "cs2000-cp", },
> > +	{}
> > +};
> > +MODULE_DEVICE_TABLE(i2c, cs2000_id);
> > +
> > +#define cs2000_read(priv, addr) \
> > +	i2c_smbus_read_byte_data(priv_to_client(priv), addr)
> > +#define cs2000_write(priv, addr, val) \
> > +	i2c_smbus_write_byte_data(priv_to_client(priv), addr, val)
> > +
> > +static int cs2000_bset(struct cs2000_priv *priv, u8 addr, u8 mask, u8 val)
> > +{
> > +	s32 data;
> > +
> > +	data = cs2000_read(priv, addr);
> > +	if (data < 0)
> > +		return data;
> > +
> > +	data &= ~mask;
> > +	data |= (val & mask);
> > +
> > +	return cs2000_write(priv, addr, data);
> > +}
> > +
> > +static int cs2000_enable_dev_config(struct cs2000_priv *priv, bool enable)
> > +{
> > +	u32 val;
> > +	int ret;
> > +
> > +	val = enable ? ENDEV1 : 0;
> > +	ret = cs2000_bset(priv, DEVICE_CFG1, ENDEV1, val);
> > +	if (ret < 0)
> > +		return ret;
> > +
> > +	val = enable ? ENDEV2 : 0;
> > +	ret = cs2000_bset(priv, GLOBAL_CFG,  ENDEV2, val);
> > +	if (ret < 0)
> > +		return ret;
> > +
> > +	return 0;
> > +}
> > +
> > +static int cs2000_clk_in_bound_rate(struct cs2000_priv *priv,
> > +				    u32 rate_in)
> > +{
> > +	u32 val;
> > +
> > +	if (rate_in >= 32000000 &&
> > +	    rate_in < 56000000)
> > +		val = 0x0;
> > +	else if (rate_in >= 16000000 &&
> > +		 rate_in < 28000000)
> > +		val = 0x1;
> > +	else if (rate_in >= 8000000 &&
> > +		 rate_in < 14000000)
> > +		val = 0x2;
> > +	else
> > +		return -EINVAL;
> > +
> > +	return cs2000_bset(priv, FUNC_CFG1, 0x3 << 3, val << 3);
> > +}
> > +
> > +static int cs2000_wait_pll_lock(struct cs2000_priv *priv)
> > +{
> > +	struct device *dev = priv_to_dev(priv);
> > +	s32 val;
> > +	unsigned int i;
> > +
> > +	for (i = 0; i < 256; i++) {
> > +		val = cs2000_read(priv, DEVICE_CTRL);
> > +		if (val < 0)
> > +			return val;
> > +		if (!(val & PLL_UNLOCK))
> > +			return 0;
> > +		udelay(1);
> > +	}
> > +
> > +	dev_err(dev, "pll lock failed\n");
> > +
> > +	return -EIO;
> > +}
> > +
> > +static int cs2000_clk_out_enable(struct cs2000_priv *priv, bool enable)
> > +{
> > +	u32 val = enable ? 0 : 0x3;
> > +
> > +	/* enable both AUX_OUT, CLK_OUT */
> > +	return cs2000_write(priv, DEVICE_CTRL, val);
> > +}
> > +
> > +static u32 cs2000_rate_to_ratio(u32 rate_in, u32 rate_out)
> > +{
> > +	u64 ratio;
> > +
> > +	/*
> > +	 * ratio = rate_out / rate_in * 2^20
> > +	 *
> > +	 * To avoid over flow, rate_out is u64
> > +	 * The result should be u32
> > +	 */
> > +	ratio = (u64)rate_out << 20;
> > +	do_div(ratio, rate_in);
> > +
> > +	return (u32)ratio;
> > +}
> > +
> > +static unsigned long cs2000_ratio_to_rate(u32 ratio, u32 rate_in)
> > +{
> > +	u64 rate_out;
> > +
> > +	/*
> > +	 * ratio = rate_out / rate_in * 2^20
> > +	 *
> > +	 * To avoid over flow, rate_out is u64
> > +	 * The result should be u32
> > +	 */
> > +
> > +	rate_out = (u64)ratio * rate_in;
> > +	return (unsigned long)(rate_out >> 20);
> > +}
> > +
> > +static int cs2000_ratio_set(struct cs2000_priv *priv,
> > +			    int ch, u32 rate_in, u32 rate_out)
> > +{
> > +	u32 val;
> > +	unsigned int i;
> > +	int ret;
> > +
> > +	if (CH_SIZE_ERR(ch))
> > +		return -EINVAL;
> > +
> > +	val = cs2000_rate_to_ratio(rate_in, rate_out);
> > +	for (i = 0; i < 4; i++) {
> > +		ret = cs2000_write(priv,
> > +				   Ratio_Add(ch, i),
> > +				   Ratio_Val(val, i));
> > +		if (ret < 0)
> > +			return ret;
> > +	}
> > +
> > +	return 0;
> > +}
> > +
> > +static u32 cs2000_ratio_get(struct cs2000_priv *priv, int ch)
> > +{
> > +	u32 tmp, val;
> > +	unsigned int i;
> > +
> > +	val = 0;
> > +	for (i = 0; i < 4; i++) {
> > +		tmp = cs2000_read(priv,
> > +				  Ratio_Add(ch, i));
> > +		if (tmp < 0)
> > +			return 0;
> > +
> > +		val |= Val_Ratio(tmp, i);
> > +	}
> > +
> > +	return val;
> > +}
> > +
> > +static int cs2000_ratio_select(struct cs2000_priv *priv, int ch)
> > +{
> > +	int ret;
> > +
> > +	if (CH_SIZE_ERR(ch))
> > +		return -EINVAL;
> > +
> > +	/*
> > +	 * FIXME
> > +	 *
> > +	 * this driver supports static ratio mode only
> > +	 * at this point
> > +	 */
> > +	ret = cs2000_bset(priv, DEVICE_CFG1, RSEL_MASK, RSEL(ch));
> > +	if (ret < 0)
> > +		return ret;
> > +
> > +	ret = cs2000_write(priv, DEVICE_CFG2, 0x0);
> > +	if (ret < 0)
> > +		return ret;
> > +
> > +	return 0;
> > +}
> > +
> > +static unsigned long cs2000_recalc_rate(struct clk_hw *hw,
> > +					unsigned long parent_rate)
> > +{
> > +	struct cs2000_priv *priv = hw_to_priv(hw);
> > +	int ch = 0; /* it uses ch0 only at this point */
> > +	u32 ratio;
> > +
> > +	ratio = cs2000_ratio_get(priv, ch);
> > +
> > +	return cs2000_ratio_to_rate(ratio, parent_rate);
> > +}
> > +
> > +static long cs2000_round_rate(struct clk_hw *hw, unsigned long rate,
> > +			      unsigned long *parent_rate)
> > +{
> > +	u32 ratio;
> > +
> > +	ratio = cs2000_rate_to_ratio(*parent_rate, rate);
> > +
> > +	return cs2000_ratio_to_rate(ratio, *parent_rate);
> > +}
> > +
> > +static int __cs2000_set_rate(struct cs2000_priv *priv, int ch,
> > +			     unsigned long rate, unsigned long parent_rate)
> > +
> > +{
> > +	int ret;
> > +
> > +	ret = cs2000_clk_in_bound_rate(priv, parent_rate);
> > +	if (ret < 0)
> > +		return ret;
> > +
> > +	ret = cs2000_ratio_set(priv, ch, parent_rate, rate);
> > +	if (ret < 0)
> > +		return ret;
> > +
> > +	ret = cs2000_ratio_select(priv, ch);
> > +	if (ret < 0)
> > +		return ret;
> > +
> > +	return 0;
> > +}
> > +
> > +static int cs2000_set_rate(struct clk_hw *hw,
> > +			   unsigned long rate, unsigned long parent_rate)
> > +{
> > +	struct cs2000_priv *priv = hw_to_priv(hw);
> > +	int ch = 0; /* it uses ch0 only at this point */
> > +
> > +	return __cs2000_set_rate(priv, ch, rate, parent_rate);
> > +}
> > +
> > +static int cs2000_enable(struct clk_hw *hw)
> > +{
> > +	struct cs2000_priv *priv = hw_to_priv(hw);
> > +	int ret;
> > +
> > +	ret = cs2000_enable_dev_config(priv, true);
> > +	if (ret < 0)
> > +		return ret;
> > +
> > +	ret = cs2000_clk_out_enable(priv, true);
> > +	if (ret < 0)
> > +		return ret;
> > +
> > +	ret = cs2000_wait_pll_lock(priv);
> > +	if (ret < 0)
> > +		return ret;
> > +
> > +	return ret;
> > +}
> > +
> > +static void cs2000_disable(struct clk_hw *hw)
> > +{
> > +	struct cs2000_priv *priv = hw_to_priv(hw);
> > +
> > +	cs2000_enable_dev_config(priv, false);
> > +
> > +	cs2000_clk_out_enable(priv, false);
> > +}
> > +
> > +static u8 cs2000_get_parent(struct clk_hw *hw)
> > +{
> > +	/* always return REF_CLK */
> > +	return REF_CLK;
> > +}
> > +
> > +static const struct clk_ops cs2000_ops = {
> > +	.get_parent	= cs2000_get_parent,
> > +	.recalc_rate	= cs2000_recalc_rate,
> > +	.round_rate	= cs2000_round_rate,
> > +	.set_rate	= cs2000_set_rate,
> > +	.prepare	= cs2000_enable,
> > +	.unprepare	= cs2000_disable,
> > +};
> > +
> > +static int cs2000_clk_get(struct cs2000_priv *priv)
> > +{
> > +	struct i2c_client *client = priv_to_client(priv);
> > +	struct device *dev = &client->dev;
> > +	struct clk *clk_in, *ref_clk;
> > +
> > +	clk_in = devm_clk_get(dev, "clk_in");
> > +	/* not yet provided */
> > +	if (IS_ERR(clk_in))
> > +		return -EPROBE_DEFER;
> > +
> > +	ref_clk = devm_clk_get(dev, "ref_clk");
> > +	/* not yet provided */
> > +	if (IS_ERR(ref_clk))
> > +		return -EPROBE_DEFER;
> > +
> > +	priv->clk_in	= clk_in;
> > +	priv->ref_clk	= ref_clk;
> > +
> > +	return 0;
> > +}
> > +
> > +static int cs2000_clk_register(struct cs2000_priv *priv)
> > +{
> > +	struct device *dev = priv_to_dev(priv);
> > +	struct device_node *np = dev->of_node;
> > +	struct clk_init_data init;
> > +	const char *name = np->name;
> > +	struct clk *clk;
> > +	static const char *parent_names[CLK_MAX];
> > +	int ch = 0; /* it uses ch0 only at this point */
> > +	int rate;
> > +	int ret;
> > +
> > +	of_property_read_string(np, "clock-output-names", &name);
> > +
> > +	/*
> > +	 * set default rate as 1/1.
> > +	 * otherwise .set_rate which setup ratio
> > +	 * is never called if user requests 1/1 rate
> > +	 */
> > +	rate = clk_get_rate(priv->ref_clk);
> > +	ret = __cs2000_set_rate(priv, ch, rate, rate);
> > +	if (ret < 0)
> > +		return ret;
> > +
> > +	parent_names[CLK_IN]	= __clk_get_name(priv->clk_in);
> > +	parent_names[REF_CLK]	= __clk_get_name(priv->ref_clk);
> > +
> > +	init.name		= name;
> > +	init.ops		= &cs2000_ops;
> > +	init.flags		= CLK_SET_RATE_GATE;
> > +	init.parent_names	= parent_names;
> > +	init.num_parents	= ARRAY_SIZE(parent_names);
> > +
> > +	priv->hw.init = &init;
> > +
> > +	clk = clk_register(dev, &priv->hw);
> > +	if (IS_ERR(clk))
> > +		return PTR_ERR(clk);
> > +
> > +	ret = of_clk_add_provider(np, of_clk_src_simple_get, clk);
> > +	if (ret < 0) {
> > +		clk_unregister(clk);
> > +		return ret;
> > +	}
> > +
> > +	priv->clk_out = clk;
> > +
> > +	return 0;
> > +}
> > +
> > +static int cs2000_version_print(struct cs2000_priv *priv)
> > +{
> > +	struct i2c_client *client = priv_to_client(priv);
> > +	struct device *dev = &client->dev;
> > +	s32 val = cs2000_read(priv, DEVICE_ID);
> > +	const char *revision;
> > +
> > +	if (val < 0)
> > +		return val;
> > +
> > +	/* CS2000 should be 0x0 */
> > +	if (0 != (val >> 3))
> > +		return -EIO;
> > +
> > +	switch (val & 0x7) {
> > +	case 0x4:
> > +		revision = "B2 / B3";
> > +		break;
> > +	case 0x6:
> > +		revision = "C1";
> > +		break;
> > +	default:
> > +		return -EIO;
> > +	}
> > +
> > +	dev_info(dev, "revision - %s\n", revision);
> > +
> > +	return 0;
> > +}
> > +
> > +static int cs2000_remove(struct i2c_client *client)
> > +{
> > +	struct cs2000_priv *priv = i2c_get_clientdata(client);
> > +	struct device *dev = &client->dev;
> > +	struct device_node *np = dev->of_node;
> > +
> > +	of_clk_del_provider(np);
> > +
> > +	clk_unregister(priv->clk_out);
> > +
> > +	return 0;
> > +}
> > +
> > +static int cs2000_probe(struct i2c_client *client,
> > +			const struct i2c_device_id *id)
> > +{
> > +	struct cs2000_priv *priv;
> > +	struct device *dev = &client->dev;
> > +	int ret;
> > +
> > +	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
> > +	if (!priv)
> > +		return -ENOMEM;
> > +
> > +	priv->client = client;
> > +	i2c_set_clientdata(client, priv);
> > +
> > +	ret = cs2000_clk_get(priv);
> > +	if (ret < 0)
> > +		return ret;
> > +
> > +	ret = cs2000_clk_register(priv);
> > +	if (ret < 0)
> > +		return ret;
> > +
> > +	ret = cs2000_version_print(priv);
> > +	if (ret < 0)
> > +		goto probe_err;
> > +
> > +	return 0;
> > +
> > +probe_err:
> > +	cs2000_remove(client);
> > +
> > +	return ret;
> > +}
> > +
> > +static struct i2c_driver cs2000_driver = {
> > +	.driver = {
> > +		.name = "cs2000-cp",
> > +		.of_match_table = cs2000_of_match,
> > +	},
> > +	.probe		= cs2000_probe,
> > +	.remove		= cs2000_remove,
> > +	.id_table	= cs2000_id,
> > +};
> > +
> > +module_i2c_driver(cs2000_driver);
> > +
> > +MODULE_DESCRIPTION("CS2000-CP driver");
> > +MODULE_AUTHOR("Kuninori Morimoto <[e-mail]>");
> > +MODULE_LICENSE("GPL v2");
> > -- 
> > 1.9.1
> > 
> > --
> > To unsubscribe from this list: send the line "unsubscribe linux-sh" in
> > the body of a message to [e-mail]
> > More majordomo info at  http://vger.kernel.org/majordomo-info.html
> 
> 
> Best regards
> ---
> Kuninori Morimoto
--
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Andy Shevchenko Nov. 6, 2015, 9:19 p.m. UTC | #3

On Tue, Oct 20, 2015 at 4:26 AM, Kuninori Morimoto
<[e-mail]> wrote:
> From: Kuninori Morimoto <[e-mail]>

Hmm… Something wrong with send-email settings?

> This patch adds CS2000 Fractional-N driver as clock provider.

> +#define CH_SIZE_ERR(ch)                ((ch < 0) || (ch >= CH_MAX))
> +#define hw_to_priv(_hw)                container_of(_hw, struct cs2000_priv, hw)

> +#define priv_to_client(priv)   (priv->client)

to_client()?

> +#define priv_to_dev(priv)      (&(priv_to_client(priv)->dev))

to_dev() ?

> +static int cs2000_bset(struct cs2000_priv *priv, u8 addr, u8 mask, u8 val)
> +{
> +       s32 data;
> +
> +       data = cs2000_read(priv, addr);
> +       if (data < 0)
> +               return data;
> +
> +       data &= ~mask;
> +       data |= (val & mask);
> +
> +       return cs2000_write(priv, addr, data);
> +}
> +
> +static int cs2000_enable_dev_config(struct cs2000_priv *priv, bool enable)
> +{
> +       u32 val;
> +       int ret;
> +
> +       val = enable ? ENDEV1 : 0;

Put in expression below?

> +       ret = cs2000_bset(priv, DEVICE_CFG1, ENDEV1, val);
> +       if (ret < 0)
> +               return ret;
> +
> +       val = enable ? ENDEV2 : 0;

Same.

> +       ret = cs2000_bset(priv, GLOBAL_CFG,  ENDEV2, val);
> +       if (ret < 0)
> +               return ret;
> +
> +       return 0;
> +}
> +
> +static int cs2000_clk_in_bound_rate(struct cs2000_priv *priv,
> +                                   u32 rate_in)
> +{
> +       u32 val;
> +
> +       if (rate_in >= 32000000 &&
> +           rate_in < 56000000)

One line here and below?

> +               val = 0x0;
> +       else if (rate_in >= 16000000 &&
> +                rate_in < 28000000)
> +               val = 0x1;
> +       else if (rate_in >= 8000000 &&
> +                rate_in < 14000000)
> +               val = 0x2;
> +       else
> +               return -EINVAL;
> +
> +       return cs2000_bset(priv, FUNC_CFG1, 0x3 << 3, val << 3);


> +}
> +
> +static int cs2000_wait_pll_lock(struct cs2000_priv *priv)
> +{
> +       struct device *dev = priv_to_dev(priv);
> +       s32 val;
> +       unsigned int i;
> +
> +       for (i = 0; i < 256; i++) {
> +               val = cs2000_read(priv, DEVICE_CTRL);
> +               if (val < 0)
> +                       return val;
> +               if (!(val & PLL_UNLOCK))
> +                       return 0;
> +               udelay(1);
> +       }

unsigned int i = 256;

do {
val = read();
…
while ((val & PLL_UNLOCK) && --i);

if (!i) {
 …
 return -EIO;

Actually -ETIMEDOUT ?

}
return 0;

> +
> +       dev_err(dev, "pll lock failed\n");
> +
> +       return -EIO;
> +}
> +
> +static int cs2000_clk_out_enable(struct cs2000_priv *priv, bool enable)
> +{
> +       u32 val = enable ? 0 : 0x3;

Redundant variable?

> +
> +       /* enable both AUX_OUT, CLK_OUT */
> +       return cs2000_write(priv, DEVICE_CTRL, val);
> +}
> +
> +static u32 cs2000_rate_to_ratio(u32 rate_in, u32 rate_out)
> +{
> +       u64 ratio;
> +
> +       /*
> +        * ratio = rate_out / rate_in * 2^20
> +        *
> +        * To avoid over flow, rate_out is u64
> +        * The result should be u32
> +        */
> +       ratio = (u64)rate_out << 20;
> +       do_div(ratio, rate_in);
> +
> +       return (u32)ratio;

No need to do explicit casting.

> +}
> +
> +static unsigned long cs2000_ratio_to_rate(u32 ratio, u32 rate_in)
> +{
> +       u64 rate_out;
> +
> +       /*
> +        * ratio = rate_out / rate_in * 2^20
> +        *
> +        * To avoid over flow, rate_out is u64
> +        * The result should be u32

u32 or unsigned long?

Btw, dots at the end of sentences.

> +        */
> +
> +       rate_out = (u64)ratio * rate_in;
> +       return (unsigned long)(rate_out >> 20);

Same.

> +}
> +
> +static int cs2000_ratio_set(struct cs2000_priv *priv,
> +                           int ch, u32 rate_in, u32 rate_out)
> +{
> +       u32 val;
> +       unsigned int i;
> +       int ret;
> +
> +       if (CH_SIZE_ERR(ch))
> +               return -EINVAL;
> +
> +       val = cs2000_rate_to_ratio(rate_in, rate_out);
> +       for (i = 0; i < 4; i++)

4 is magic, you have define already.

> +               ret = cs2000_write(priv,
> +                                  Ratio_Add(ch, i),
> +                                  Ratio_Val(val, i));
> +               if (ret < 0)
> +                       return ret;
> +       }
> +
> +       return 0;
> +}
> +
> +static u32 cs2000_ratio_get(struct cs2000_priv *priv, int ch)
> +{
> +       u32 tmp, val;
> +       unsigned int i;
> +
> +       val = 0;
> +       for (i = 0; i < 4; i++) {

Same.

> +               tmp = cs2000_read(priv,
> +                                 Ratio_Add(ch, i));

One line?

> +               if (tmp < 0)
> +                       return 0;
> +
> +               val |= Val_Ratio(tmp, i);
> +       }
> +
> +       return val;
> +}
> +
> +static int cs2000_ratio_select(struct cs2000_priv *priv, int ch)
> +{
> +       int ret;
> +
> +       if (CH_SIZE_ERR(ch))
> +               return -EINVAL;
> +

> +       /*
> +        * FIXME
> +        *
> +        * this driver supports static ratio mode only
> +        * at this point
> +        */

One line?

> +       ret = cs2000_bset(priv, DEVICE_CFG1, RSEL_MASK, RSEL(ch));
> +       if (ret < 0)
> +               return ret;
> +
> +       ret = cs2000_write(priv, DEVICE_CFG2, 0x0);
> +       if (ret < 0)
> +               return ret;
> +
> +       return 0;
> +}
> +
> +static unsigned long cs2000_recalc_rate(struct clk_hw *hw,
> +                                       unsigned long parent_rate)
> +{
> +       struct cs2000_priv *priv = hw_to_priv(hw);
> +       int ch = 0; /* it uses ch0 only at this point */
> +       u32 ratio;
> +
> +       ratio = cs2000_ratio_get(priv, ch);
> +
> +       return cs2000_ratio_to_rate(ratio, parent_rate);
> +}
> +
> +static long cs2000_round_rate(struct clk_hw *hw, unsigned long rate,
> +                             unsigned long *parent_rate)
> +{
> +       u32 ratio;
> +
> +       ratio = cs2000_rate_to_ratio(*parent_rate, rate);
> +
> +       return cs2000_ratio_to_rate(ratio, *parent_rate);
> +}
> +
> +static int __cs2000_set_rate(struct cs2000_priv *priv, int ch,
> +                            unsigned long rate, unsigned long parent_rate)
> +
> +{
> +       int ret;
> +
> +       ret = cs2000_clk_in_bound_rate(priv, parent_rate);
> +       if (ret < 0)
> +               return ret;
> +
> +       ret = cs2000_ratio_set(priv, ch, parent_rate, rate);
> +       if (ret < 0)
> +               return ret;
> +
> +       ret = cs2000_ratio_select(priv, ch);
> +       if (ret < 0)
> +               return ret;
> +
> +       return 0;
> +}
> +
> +static int cs2000_set_rate(struct clk_hw *hw,
> +                          unsigned long rate, unsigned long parent_rate)
> +{
> +       struct cs2000_priv *priv = hw_to_priv(hw);
> +       int ch = 0; /* it uses ch0 only at this point */
> +
> +       return __cs2000_set_rate(priv, ch, rate, parent_rate);
> +}
> +
> +static int cs2000_enable(struct clk_hw *hw)
> +{
> +       struct cs2000_priv *priv = hw_to_priv(hw);
> +       int ret;
> +
> +       ret = cs2000_enable_dev_config(priv, true);
> +       if (ret < 0)
> +               return ret;
> +
> +       ret = cs2000_clk_out_enable(priv, true);
> +       if (ret < 0)
> +               return ret;
> +
> +       ret = cs2000_wait_pll_lock(priv);
> +       if (ret < 0)
> +               return ret;
> +
> +       return ret;
> +}
> +
> +static void cs2000_disable(struct clk_hw *hw)
> +{
> +       struct cs2000_priv *priv = hw_to_priv(hw);
> +
> +       cs2000_enable_dev_config(priv, false);
> +
> +       cs2000_clk_out_enable(priv, false);
> +}
> +
> +static u8 cs2000_get_parent(struct clk_hw *hw)
> +{
> +       /* always return REF_CLK */
> +       return REF_CLK;
> +}
> +
> +static const struct clk_ops cs2000_ops = {
> +       .get_parent     = cs2000_get_parent,
> +       .recalc_rate    = cs2000_recalc_rate,
> +       .round_rate     = cs2000_round_rate,
> +       .set_rate       = cs2000_set_rate,
> +       .prepare        = cs2000_enable,
> +       .unprepare      = cs2000_disable,
> +};
> +
> +static int cs2000_clk_get(struct cs2000_priv *priv)
> +{
> +       struct i2c_client *client = priv_to_client(priv);
> +       struct device *dev = &client->dev;
> +       struct clk *clk_in, *ref_clk;
> +
> +       clk_in = devm_clk_get(dev, "clk_in");
> +       /* not yet provided */
> +       if (IS_ERR(clk_in))
> +               return -EPROBE_DEFER;
> +
> +       ref_clk = devm_clk_get(dev, "ref_clk");
> +       /* not yet provided */
> +       if (IS_ERR(ref_clk))
> +               return -EPROBE_DEFER;
> +
> +       priv->clk_in    = clk_in;
> +       priv->ref_clk   = ref_clk;
> +
> +       return 0;
> +}
> +
> +static int cs2000_clk_register(struct cs2000_priv *priv)
> +{
> +       struct device *dev = priv_to_dev(priv);
> +       struct device_node *np = dev->of_node;
> +       struct clk_init_data init;
> +       const char *name = np->name;
> +       struct clk *clk;
> +       static const char *parent_names[CLK_MAX];
> +       int ch = 0; /* it uses ch0 only at this point */
> +       int rate;
> +       int ret;
> +
> +       of_property_read_string(np, "clock-output-names", &name);

What about device property API?

> +
> +       /*
> +        * set default rate as 1/1.
> +        * otherwise .set_rate which setup ratio
> +        * is never called if user requests 1/1 rate
> +        */
> +       rate = clk_get_rate(priv->ref_clk);
> +       ret = __cs2000_set_rate(priv, ch, rate, rate);
> +       if (ret < 0)
> +               return ret;
> +
> +       parent_names[CLK_IN]    = __clk_get_name(priv->clk_in);
> +       parent_names[REF_CLK]   = __clk_get_name(priv->ref_clk);
> +
> +       init.name               = name;
> +       init.ops                = &cs2000_ops;
> +       init.flags              = CLK_SET_RATE_GATE;
> +       init.parent_names       = parent_names;
> +       init.num_parents        = ARRAY_SIZE(parent_names);
> +
> +       priv->hw.init = &init;
> +
> +       clk = clk_register(dev, &priv->hw);
> +       if (IS_ERR(clk))
> +               return PTR_ERR(clk);
> +
> +       ret = of_clk_add_provider(np, of_clk_src_simple_get, clk);
> +       if (ret < 0) {
> +               clk_unregister(clk);
> +               return ret;
> +       }
> +
> +       priv->clk_out = clk;
> +
> +       return 0;
> +}
> +
> +static int cs2000_version_print(struct cs2000_priv *priv)
> +{
> +       struct i2c_client *client = priv_to_client(priv);
> +       struct device *dev = &client->dev;
> +       s32 val = cs2000_read(priv, DEVICE_ID);
> +       const char *revision;
> +

Move read here to see how val is assigned.

s32 val;

…

val = read();

> +       if (val < 0)
> +               return val;
> +
> +       /* CS2000 should be 0x0 */
> +       if (0 != (val >> 3))

if (val >> 3)

> +               return -EIO;
> +
> +       switch (val & 0x7) {

magic

> +       case 0x4:

magic

> +               revision = "B2 / B3";
> +               break;
> +       case 0x6:

magic

> +               revision = "C1";
> +               break;
> +       default:
> +               return -EIO;
> +       }
> +
> +       dev_info(dev, "revision - %s\n", revision);
> +
> +       return 0;
> +}
> +
> +static int cs2000_remove(struct i2c_client *client)
> +{
> +       struct cs2000_priv *priv = i2c_get_clientdata(client);
> +       struct device *dev = &client->dev;
> +       struct device_node *np = dev->of_node;
> +
> +       of_clk_del_provider(np);
> +
> +       clk_unregister(priv->clk_out);
> +
> +       return 0;
> +}
> +
> +static int cs2000_probe(struct i2c_client *client,
> +                       const struct i2c_device_id *id)
> +{
> +       struct cs2000_priv *priv;
> +       struct device *dev = &client->dev;
> +       int ret;
> +
> +       priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
> +       if (!priv)
> +               return -ENOMEM;
> +
> +       priv->client = client;
> +       i2c_set_clientdata(client, priv);
> +
> +       ret = cs2000_clk_get(priv);
> +       if (ret < 0)
> +               return ret;
> +
> +       ret = cs2000_clk_register(priv);
> +       if (ret < 0)
> +               return ret;
> +
> +       ret = cs2000_version_print(priv);
> +       if (ret < 0)
> +               goto probe_err;
> +
> +       return 0;
> +
> +probe_err:
> +       cs2000_remove(client);


> +
> +       return ret;
> +}
> +
> +static struct i2c_driver cs2000_driver = {
> +       .driver = {
> +               .name = "cs2000-cp",
> +               .of_match_table = cs2000_of_match,
> +       },
> +       .probe          = cs2000_probe,
> +       .remove         = cs2000_remove,
> +       .id_table       = cs2000_id,
> +};
> +
> +module_i2c_driver(cs2000_driver);
> +
> +MODULE_DESCRIPTION("CS2000-CP driver");
> +MODULE_AUTHOR("Kuninori Morimoto <[e-mail]>");
> +MODULE_LICENSE("GPL v2");
> --
> 1.9.1
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to [e-mail]
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> Please read the FAQ at  http://www.tux.org/lkml/

Kuninori Morimoto Nov. 9, 2015, 12:49 a.m. UTC | #4

Hi

Thank you for your feedback

> > From: Kuninori Morimoto <[e-mail]>
> 
> Hmm… Something wrong with send-email settings?

Nothing wrong. I would like to overwrite Author
(Sender and Author are same though...)

> > +#define priv_to_client(priv)   (priv->client)
> 
> to_client()?
> 
> > +#define priv_to_dev(priv)      (&(priv_to_client(priv)->dev))
> 
> to_dev() ?

I would like to have "from"

> > +static int cs2000_enable_dev_config(struct cs2000_priv *priv, bool enable)
> > +{
> > +       u32 val;
> > +       int ret;
> > +
> > +       val = enable ? ENDEV1 : 0;
> 
> Put in expression below?
> 
> > +       ret = cs2000_bset(priv, DEVICE_CFG1, ENDEV1, val);
> > +       if (ret < 0)
> > +               return ret;
> > +
> > +       val = enable ? ENDEV2 : 0;
> 
> Same.

OK

> > +       if (rate_in >= 32000000 &&
> > +           rate_in < 56000000)
> 
> One line here and below?

OK


> > +static int cs2000_wait_pll_lock(struct cs2000_priv *priv)
> > +{
> > +       struct device *dev = priv_to_dev(priv);
> > +       s32 val;
> > +       unsigned int i;
> > +
> > +       for (i = 0; i < 256; i++) {
> > +               val = cs2000_read(priv, DEVICE_CTRL);
> > +               if (val < 0)
> > +                       return val;
> > +               if (!(val & PLL_UNLOCK))
> > +                       return 0;
> > +               udelay(1);
> > +       }
> 
> unsigned int i = 256;
> 
> do {
> val = read();
> …
> while ((val & PLL_UNLOCK) && --i);
> 
> if (!i) {
>  …
>  return -EIO;
> 
> Actually -ETIMEDOUT ?
> 
> }

What is the motivation of above ?
It needs "i" anyway ? it needs to check (val < 0) anyway ?
what is the difference between do {} while <-> for(xxx)

> > +static int cs2000_clk_out_enable(struct cs2000_priv *priv, bool enable)
> > +{
> > +       u32 val = enable ? 0 : 0x3;
> 
> Redundant variable?

OK


> > +static u32 cs2000_rate_to_ratio(u32 rate_in, u32 rate_out)
> > +{
> > +       u64 ratio;
> > +
> > +       /*
> > +        * ratio = rate_out / rate_in * 2^20
> > +        *
> > +        * To avoid over flow, rate_out is u64
> > +        * The result should be u32
> > +        */
> > +       ratio = (u64)rate_out << 20;
> > +       do_div(ratio, rate_in);
> > +
> > +       return (u32)ratio;
> 
> No need to do explicit casting.
> 
> > +}
> > +
> > +static unsigned long cs2000_ratio_to_rate(u32 ratio, u32 rate_in)
> > +{
> > +       u64 rate_out;
> > +
> > +       /*
> > +        * ratio = rate_out / rate_in * 2^20
> > +        *
> > +        * To avoid over flow, rate_out is u64
> > +        * The result should be u32
> 
> u32 or unsigned long?
> 
> Btw, dots at the end of sentences.
> 
> > +        */
> > +
> > +       rate_out = (u64)ratio * rate_in;
> > +       return (unsigned long)(rate_out >> 20);
> 
> Same.

OK

> > +static int cs2000_ratio_set(struct cs2000_priv *priv,
> > +                           int ch, u32 rate_in, u32 rate_out)
> > +{
> > +       u32 val;
> > +       unsigned int i;
> > +       int ret;
> > +
> > +       if (CH_SIZE_ERR(ch))
> > +               return -EINVAL;
> > +
> > +       val = cs2000_rate_to_ratio(rate_in, rate_out);
> > +       for (i = 0; i < 4; i++)
> 
> 4 is magic, you have define already.

OK

> > +       /*
> > +        * FIXME
> > +        *
> > +        * this driver supports static ratio mode only
> > +        * at this point
> > +        */
> 
> One line?

OK

> > +static int cs2000_clk_register(struct cs2000_priv *priv)
> > +{
> > +       struct device *dev = priv_to_dev(priv);
> > +       struct device_node *np = dev->of_node;
> > +       struct clk_init_data init;
> > +       const char *name = np->name;
> > +       struct clk *clk;
> > +       static const char *parent_names[CLK_MAX];
> > +       int ch = 0; /* it uses ch0 only at this point */
> > +       int rate;
> > +       int ret;
> > +
> > +       of_property_read_string(np, "clock-output-names", &name);
> 
> What about device property API?

Sorry, which API ?
Many other clk-xxx.c are using this style ?

> > +static int cs2000_version_print(struct cs2000_priv *priv)
> > +{
> > +       struct i2c_client *client = priv_to_client(priv);
> > +       struct device *dev = &client->dev;
> > +       s32 val = cs2000_read(priv, DEVICE_ID);
> > +       const char *revision;
> > +
> 
> Move read here to see how val is assigned.
> 
> s32 val;
> 
> …
> 
> val = read();
> 
> > +       if (val < 0)
> > +               return val;
> > +
> > +       /* CS2000 should be 0x0 */
> > +       if (0 != (val >> 3))
> 
> if (val >> 3)
> 
> > +               return -EIO;
> > +
> > +       switch (val & 0x7) {
> 
> magic
> 
> > +       case 0x4:
> 
> magic
> 
> > +               revision = "B2 / B3";
> > +               break;
> > +       case 0x6:
> 
> magic

OK


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Andy Shevchenko Nov. 9, 2015, 9:21 a.m. UTC | #5

On Mon, Nov 9, 2015 at 2:49 AM, Kuninori Morimoto
<[e-mail]> wrote:

>> > +static int cs2000_wait_pll_lock(struct cs2000_priv *priv)
>> > +{
>> > +       struct device *dev = priv_to_dev(priv);
>> > +       s32 val;
>> > +       unsigned int i;
>> > +
>> > +       for (i = 0; i < 256; i++) {
>> > +               val = cs2000_read(priv, DEVICE_CTRL);
>> > +               if (val < 0)
>> > +                       return val;
>> > +               if (!(val & PLL_UNLOCK))
>> > +                       return 0;
>> > +               udelay(1);
>> > +       }
>>
>> unsigned int i = 256;
>>
>> do {
>> val = read();
>> …
>> while ((val & PLL_UNLOCK) && --i);
>>
>> if (!i) {
>>  …
>>  return -EIO;
>>
>> Actually -ETIMEDOUT ?
>>
>> }
>
> What is the motivation of above ?
> It needs "i" anyway ? it needs to check (val < 0) anyway ?
> what is the difference between do {} while <-> for(xxx)

Just a style.
Still the question about error code.

>> > +       of_property_read_string(np, "clock-output-names", &name);
>>
>> What about device property API?
>
> Sorry, which API ?
> Many other clk-xxx.c are using this style ?

Never mind then.

Kuninori Morimoto Nov. 10, 2015, 12:26 a.m. UTC | #6

Hi Andy

> >> > +static int cs2000_wait_pll_lock(struct cs2000_priv *priv)
> >> > +{
> >> > +       struct device *dev = priv_to_dev(priv);
> >> > +       s32 val;
> >> > +       unsigned int i;
> >> > +
> >> > +       for (i = 0; i < 256; i++) {
> >> > +               val = cs2000_read(priv, DEVICE_CTRL);
> >> > +               if (val < 0)
> >> > +                       return val;
> >> > +               if (!(val & PLL_UNLOCK))
> >> > +                       return 0;
> >> > +               udelay(1);
> >> > +       }
> >>
> >> unsigned int i = 256;
> >>
> >> do {
> >> val = read();
> >> …
> >> while ((val & PLL_UNLOCK) && --i);
> >>
> >> if (!i) {
> >>  …
> >>  return -EIO;
> >>
> >> Actually -ETIMEDOUT ?
> >>
> >> }
> >
> > What is the motivation of above ?
> > It needs "i" anyway ? it needs to check (val < 0) anyway ?
> > what is the difference between do {} while <-> for(xxx)
> 
> Just a style.
> Still the question about error code.

OK. do {} while is not bad, but for () loop
can avoid pointless check I think. I would like to use it.
And yes, next version will use -ETIMEDOUT

> >> > +       of_property_read_string(np, "clock-output-names", &name);
> >>
> >> What about device property API?
> >
> > Sorry, which API ?
> > Many other clk-xxx.c are using this style ?
> 
> Never mind then.

Thanks
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Patch

diff --git a/Documentation/devicetree/bindings/clock/cs2000-cp.txt b/Documentation/devicetree/bindings/clock/cs2000-cp.txt
new file mode 100644
index 0000000..54e6df0
--- /dev/null
+++ b/Documentation/devicetree/bindings/clock/cs2000-cp.txt
@@ -0,0 +1,22 @@ 
+CIRRUS LOGIC Fractional-N Clock Synthesizer & Clock Multiplier
+
+Required properties:
+
+- compatible:		"cirrus,cs2000-cp"
+- reg:			The chip select number on the I2C bus
+- clocks:		common clock binding for CLK_IN, XTI/REF_CLK
+- clock-names:		CLK_IN : clk_in, XTI/REF_CLK : ref_clk
+- #clock-cells:		must be <0>
+
+Example:
+
+&i2c2 {
+	...
+	cs2000: clk_multiplier@4f {
+		#clock-cells = <0>;
+		compatible = "cirrus,cs2000-cp";
+		reg = <0x4f>;
+		clocks = <&rcar_sound 0>, <&x12_clk>;
+		clock-names = "clk_in", "ref_clk";
+	};
+};
diff --git a/drivers/clk/Kconfig b/drivers/clk/Kconfig
index 42f7120..0e961b2 100644
--- a/drivers/clk/Kconfig
+++ b/drivers/clk/Kconfig
@@ -95,6 +95,12 @@  config COMMON_CLK_CDCE925
 	  Given a target output frequency, the driver will set the PLL and
 	  divider to best approximate the desired output.
 
+config COMMON_CLK_CS2000_CP
+	tristate "Clock driver for CS2000 Fractional-N Clock Synthesizer & Clock Multiplier"
+	depends on I2C
+	help
+	  If you say yes here you get support for the CS2000 clock multiplier.
+
 config COMMON_CLK_S2MPS11
 	tristate "Clock driver for S2MPS1X/S5M8767 MFD"
 	depends on MFD_SEC_CORE
diff --git a/drivers/clk/Makefile b/drivers/clk/Makefile
index 9d31e2c..2fb77a8 100644
--- a/drivers/clk/Makefile
+++ b/drivers/clk/Makefile
@@ -21,6 +21,7 @@  obj-$(CONFIG_COMMON_CLK_AXI_CLKGEN)	+= clk-axi-clkgen.o
 obj-$(CONFIG_ARCH_AXXIA)		+= clk-axm5516.o
 obj-$(CONFIG_ARCH_BCM2835)		+= clk-bcm2835.o
 obj-$(CONFIG_COMMON_CLK_CDCE706)	+= clk-cdce706.o
+obj-$(CONFIG_COMMON_CLK_CS2000_CP)	+= clk-cs2000-cp.o
 obj-$(CONFIG_ARCH_CLPS711X)		+= clk-clps711x.o
 obj-$(CONFIG_ARCH_EFM32)		+= clk-efm32gg.o
 obj-$(CONFIG_ARCH_HIGHBANK)		+= clk-highbank.o
diff --git a/drivers/clk/clk-cs2000-cp.c b/drivers/clk/clk-cs2000-cp.c
new file mode 100644
index 0000000..71d9340
--- /dev/null
+++ b/drivers/clk/clk-cs2000-cp.c
@@ -0,0 +1,510 @@ 
+/*
+ * CS2000  --  CIRRUS LOGIC Fractional-N Clock Synthesizer & Clock Multiplier
+ *
+ * Copyright (C) 2015 Renesas Electronics Corporation
+ * Kuninori Morimoto <[e-mail]>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+#include <linux/clk-provider.h>
+#include <linux/delay.h>
+#include <linux/clk.h>
+#include <linux/i2c.h>
+#include <linux/of_device.h>
+#include <linux/module.h>
+
+#define CH_MAX 4
+
+#define DEVICE_ID	0x1
+#define DEVICE_CTRL	0x2
+#define DEVICE_CFG1	0x3
+#define DEVICE_CFG2	0x4
+#define GLOBAL_CFG	0x5
+#define Ratio_Add(x, nth)	(6 + (x * 4) + (nth))
+#define Ratio_Val(x, nth)	((x >> (24 - (8 * nth))) & 0xFF)
+#define Val_Ratio(x, nth)	((x & 0xFF) << (24 - (8 * nth)))
+#define FUNC_CFG1	0x16
+#define FUNC_CFG2	0x17
+
+/* DEVICE_CTRL */
+#define PLL_UNLOCK	(1 << 7)
+
+/* DEVICE_CFG1 */
+#define RSEL(x)		(((x) & 0x3) << 3)
+#define RSEL_MASK	RSEL(0x3)
+#define ENDEV1		(0x1)
+
+/* GLOBAL_CFG */
+#define ENDEV2		(0x1)
+
+#define CH_SIZE_ERR(ch)		((ch < 0) || (ch >= CH_MAX))
+#define hw_to_priv(_hw)		container_of(_hw, struct cs2000_priv, hw)
+#define priv_to_client(priv)	(priv->client)
+#define priv_to_dev(priv)	(&(priv_to_client(priv)->dev))
+
+#define CLK_IN	0
+#define REF_CLK	1
+#define CLK_MAX 2
+
+struct cs2000_priv {
+	struct clk_hw hw;
+	struct i2c_client *client;
+	struct clk *clk_in;
+	struct clk *ref_clk;
+	struct clk *clk_out;
+};
+
+static const struct of_device_id cs2000_of_match[] = {
+	{ .compatible = "cirrus,cs2000-cp", },
+	{},
+};
+MODULE_DEVICE_TABLE(of, cs2000_of_match);
+
+static const struct i2c_device_id cs2000_id[] = {
+	{ "cs2000-cp", },
+	{}
+};
+MODULE_DEVICE_TABLE(i2c, cs2000_id);
+
+#define cs2000_read(priv, addr) \
+	i2c_smbus_read_byte_data(priv_to_client(priv), addr)
+#define cs2000_write(priv, addr, val) \
+	i2c_smbus_write_byte_data(priv_to_client(priv), addr, val)
+
+static int cs2000_bset(struct cs2000_priv *priv, u8 addr, u8 mask, u8 val)
+{
+	s32 data;
+
+	data = cs2000_read(priv, addr);
+	if (data < 0)
+		return data;
+
+	data &= ~mask;
+	data |= (val & mask);
+
+	return cs2000_write(priv, addr, data);
+}
+
+static int cs2000_enable_dev_config(struct cs2000_priv *priv, bool enable)
+{
+	u32 val;
+	int ret;
+
+	val = enable ? ENDEV1 : 0;
+	ret = cs2000_bset(priv, DEVICE_CFG1, ENDEV1, val);
+	if (ret < 0)
+		return ret;
+
+	val = enable ? ENDEV2 : 0;
+	ret = cs2000_bset(priv, GLOBAL_CFG,  ENDEV2, val);
+	if (ret < 0)
+		return ret;
+
+	return 0;
+}
+
+static int cs2000_clk_in_bound_rate(struct cs2000_priv *priv,
+				    u32 rate_in)
+{
+	u32 val;
+
+	if (rate_in >= 32000000 &&
+	    rate_in < 56000000)
+		val = 0x0;
+	else if (rate_in >= 16000000 &&
+		 rate_in < 28000000)
+		val = 0x1;
+	else if (rate_in >= 8000000 &&
+		 rate_in < 14000000)
+		val = 0x2;
+	else
+		return -EINVAL;
+
+	return cs2000_bset(priv, FUNC_CFG1, 0x3 << 3, val << 3);
+}
+
+static int cs2000_wait_pll_lock(struct cs2000_priv *priv)
+{
+	struct device *dev = priv_to_dev(priv);
+	s32 val;
+	unsigned int i;
+
+	for (i = 0; i < 256; i++) {
+		val = cs2000_read(priv, DEVICE_CTRL);
+		if (val < 0)
+			return val;
+		if (!(val & PLL_UNLOCK))
+			return 0;
+		udelay(1);
+	}
+
+	dev_err(dev, "pll lock failed\n");
+
+	return -EIO;
+}
+
+static int cs2000_clk_out_enable(struct cs2000_priv *priv, bool enable)
+{
+	u32 val = enable ? 0 : 0x3;
+
+	/* enable both AUX_OUT, CLK_OUT */
+	return cs2000_write(priv, DEVICE_CTRL, val);
+}
+
+static u32 cs2000_rate_to_ratio(u32 rate_in, u32 rate_out)
+{
+	u64 ratio;
+
+	/*
+	 * ratio = rate_out / rate_in * 2^20
+	 *
+	 * To avoid over flow, rate_out is u64
+	 * The result should be u32
+	 */
+	ratio = (u64)rate_out << 20;
+	do_div(ratio, rate_in);
+
+	return (u32)ratio;
+}
+
+static unsigned long cs2000_ratio_to_rate(u32 ratio, u32 rate_in)
+{
+	u64 rate_out;
+
+	/*
+	 * ratio = rate_out / rate_in * 2^20
+	 *
+	 * To avoid over flow, rate_out is u64
+	 * The result should be u32
+	 */
+
+	rate_out = (u64)ratio * rate_in;
+	return (unsigned long)(rate_out >> 20);
+}
+
+static int cs2000_ratio_set(struct cs2000_priv *priv,
+			    int ch, u32 rate_in, u32 rate_out)
+{
+	u32 val;
+	unsigned int i;
+	int ret;
+
+	if (CH_SIZE_ERR(ch))
+		return -EINVAL;
+
+	val = cs2000_rate_to_ratio(rate_in, rate_out);
+	for (i = 0; i < 4; i++) {
+		ret = cs2000_write(priv,
+				   Ratio_Add(ch, i),
+				   Ratio_Val(val, i));
+		if (ret < 0)
+			return ret;
+	}
+
+	return 0;
+}
+
+static u32 cs2000_ratio_get(struct cs2000_priv *priv, int ch)
+{
+	u32 tmp, val;
+	unsigned int i;
+
+	val = 0;
+	for (i = 0; i < 4; i++) {
+		tmp = cs2000_read(priv,
+				  Ratio_Add(ch, i));
+		if (tmp < 0)
+			return 0;
+
+		val |= Val_Ratio(tmp, i);
+	}
+
+	return val;
+}
+
+static int cs2000_ratio_select(struct cs2000_priv *priv, int ch)
+{
+	int ret;
+
+	if (CH_SIZE_ERR(ch))
+		return -EINVAL;
+
+	/*
+	 * FIXME
+	 *
+	 * this driver supports static ratio mode only
+	 * at this point
+	 */
+	ret = cs2000_bset(priv, DEVICE_CFG1, RSEL_MASK, RSEL(ch));
+	if (ret < 0)
+		return ret;
+
+	ret = cs2000_write(priv, DEVICE_CFG2, 0x0);
+	if (ret < 0)
+		return ret;
+
+	return 0;
+}
+
+static unsigned long cs2000_recalc_rate(struct clk_hw *hw,
+					unsigned long parent_rate)
+{
+	struct cs2000_priv *priv = hw_to_priv(hw);
+	int ch = 0; /* it uses ch0 only at this point */
+	u32 ratio;
+
+	ratio = cs2000_ratio_get(priv, ch);
+
+	return cs2000_ratio_to_rate(ratio, parent_rate);
+}
+
+static long cs2000_round_rate(struct clk_hw *hw, unsigned long rate,
+			      unsigned long *parent_rate)
+{
+	u32 ratio;
+
+	ratio = cs2000_rate_to_ratio(*parent_rate, rate);
+
+	return cs2000_ratio_to_rate(ratio, *parent_rate);
+}
+
+static int __cs2000_set_rate(struct cs2000_priv *priv, int ch,
+			     unsigned long rate, unsigned long parent_rate)
+
+{
+	int ret;
+
+	ret = cs2000_clk_in_bound_rate(priv, parent_rate);
+	if (ret < 0)
+		return ret;
+
+	ret = cs2000_ratio_set(priv, ch, parent_rate, rate);
+	if (ret < 0)
+		return ret;
+
+	ret = cs2000_ratio_select(priv, ch);
+	if (ret < 0)
+		return ret;
+
+	return 0;
+}
+
+static int cs2000_set_rate(struct clk_hw *hw,
+			   unsigned long rate, unsigned long parent_rate)
+{
+	struct cs2000_priv *priv = hw_to_priv(hw);
+	int ch = 0; /* it uses ch0 only at this point */
+
+	return __cs2000_set_rate(priv, ch, rate, parent_rate);
+}
+
+static int cs2000_enable(struct clk_hw *hw)
+{
+	struct cs2000_priv *priv = hw_to_priv(hw);
+	int ret;
+
+	ret = cs2000_enable_dev_config(priv, true);
+	if (ret < 0)
+		return ret;
+
+	ret = cs2000_clk_out_enable(priv, true);
+	if (ret < 0)
+		return ret;
+
+	ret = cs2000_wait_pll_lock(priv);
+	if (ret < 0)
+		return ret;
+
+	return ret;
+}
+
+static void cs2000_disable(struct clk_hw *hw)
+{
+	struct cs2000_priv *priv = hw_to_priv(hw);
+
+	cs2000_enable_dev_config(priv, false);
+
+	cs2000_clk_out_enable(priv, false);
+}
+
+static u8 cs2000_get_parent(struct clk_hw *hw)
+{
+	/* always return REF_CLK */
+	return REF_CLK;
+}
+
+static const struct clk_ops cs2000_ops = {
+	.get_parent	= cs2000_get_parent,
+	.recalc_rate	= cs2000_recalc_rate,
+	.round_rate	= cs2000_round_rate,
+	.set_rate	= cs2000_set_rate,
+	.prepare	= cs2000_enable,
+	.unprepare	= cs2000_disable,
+};
+
+static int cs2000_clk_get(struct cs2000_priv *priv)
+{
+	struct i2c_client *client = priv_to_client(priv);
+	struct device *dev = &client->dev;
+	struct clk *clk_in, *ref_clk;
+
+	clk_in = devm_clk_get(dev, "clk_in");
+	/* not yet provided */
+	if (IS_ERR(clk_in))
+		return -EPROBE_DEFER;
+
+	ref_clk = devm_clk_get(dev, "ref_clk");
+	/* not yet provided */
+	if (IS_ERR(ref_clk))
+		return -EPROBE_DEFER;
+
+	priv->clk_in	= clk_in;
+	priv->ref_clk	= ref_clk;
+
+	return 0;
+}
+
+static int cs2000_clk_register(struct cs2000_priv *priv)
+{
+	struct device *dev = priv_to_dev(priv);
+	struct device_node *np = dev->of_node;
+	struct clk_init_data init;
+	const char *name = np->name;
+	struct clk *clk;
+	static const char *parent_names[CLK_MAX];
+	int ch = 0; /* it uses ch0 only at this point */
+	int rate;
+	int ret;
+
+	of_property_read_string(np, "clock-output-names", &name);
+
+	/*
+	 * set default rate as 1/1.
+	 * otherwise .set_rate which setup ratio
+	 * is never called if user requests 1/1 rate
+	 */
+	rate = clk_get_rate(priv->ref_clk);
+	ret = __cs2000_set_rate(priv, ch, rate, rate);
+	if (ret < 0)
+		return ret;
+
+	parent_names[CLK_IN]	= __clk_get_name(priv->clk_in);
+	parent_names[REF_CLK]	= __clk_get_name(priv->ref_clk);
+
+	init.name		= name;
+	init.ops		= &cs2000_ops;
+	init.flags		= CLK_SET_RATE_GATE;
+	init.parent_names	= parent_names;
+	init.num_parents	= ARRAY_SIZE(parent_names);
+
+	priv->hw.init = &init;
+
+	clk = clk_register(dev, &priv->hw);
+	if (IS_ERR(clk))
+		return PTR_ERR(clk);
+
+	ret = of_clk_add_provider(np, of_clk_src_simple_get, clk);
+	if (ret < 0) {
+		clk_unregister(clk);
+		return ret;
+	}
+
+	priv->clk_out = clk;
+
+	return 0;
+}
+
+static int cs2000_version_print(struct cs2000_priv *priv)
+{
+	struct i2c_client *client = priv_to_client(priv);
+	struct device *dev = &client->dev;
+	s32 val = cs2000_read(priv, DEVICE_ID);
+	const char *revision;
+
+	if (val < 0)
+		return val;
+
+	/* CS2000 should be 0x0 */
+	if (0 != (val >> 3))
+		return -EIO;
+
+	switch (val & 0x7) {
+	case 0x4:
+		revision = "B2 / B3";
+		break;
+	case 0x6:
+		revision = "C1";
+		break;
+	default:
+		return -EIO;
+	}
+
+	dev_info(dev, "revision - %s\n", revision);
+
+	return 0;
+}
+
+static int cs2000_remove(struct i2c_client *client)
+{
+	struct cs2000_priv *priv = i2c_get_clientdata(client);
+	struct device *dev = &client->dev;
+	struct device_node *np = dev->of_node;
+
+	of_clk_del_provider(np);
+
+	clk_unregister(priv->clk_out);
+
+	return 0;
+}
+
+static int cs2000_probe(struct i2c_client *client,
+			const struct i2c_device_id *id)
+{
+	struct cs2000_priv *priv;
+	struct device *dev = &client->dev;
+	int ret;
+
+	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	priv->client = client;
+	i2c_set_clientdata(client, priv);
+
+	ret = cs2000_clk_get(priv);
+	if (ret < 0)
+		return ret;
+
+	ret = cs2000_clk_register(priv);
+	if (ret < 0)
+		return ret;
+
+	ret = cs2000_version_print(priv);
+	if (ret < 0)
+		goto probe_err;
+
+	return 0;
+
+probe_err:
+	cs2000_remove(client);
+
+	return ret;
+}
+
+static struct i2c_driver cs2000_driver = {
+	.driver = {
+		.name = "cs2000-cp",
+		.of_match_table = cs2000_of_match,
+	},
+	.probe		= cs2000_probe,
+	.remove		= cs2000_remove,
+	.id_table	= cs2000_id,
+};
+
+module_i2c_driver(cs2000_driver);
+
+MODULE_DESCRIPTION("CS2000-CP driver");
+MODULE_AUTHOR("Kuninori Morimoto <[e-mail]>");
+MODULE_LICENSE("GPL v2");