diff mbox

[03/12] clk: samsung: add clock driver for external clock outputs

Message ID 201312131359.36576.heiko@sntech.de (mailing list archive)
State Not Applicable, archived
Headers show

Commit Message

Heiko Stuebner Dec. 13, 2013, 12:59 p.m. UTC
This adds a driver for controlling the external clock outputs of
s3c24xx architectures including the dclk muxes and dividers.

Signed-off-by: Heiko Stuebner <heiko@sntech.de>
---
 drivers/clk/samsung/Makefile                     |    1 +
 drivers/clk/samsung/clk-s3c2410-dclk.c           |  517 ++++++++++++++++++++++
 include/dt-bindings/clock/samsung,s3c2410-dclk.h |   28 ++
 3 files changed, 546 insertions(+)
 create mode 100644 drivers/clk/samsung/clk-s3c2410-dclk.c
 create mode 100644 include/dt-bindings/clock/samsung,s3c2410-dclk.h

Comments

Mike Turquette Dec. 31, 2013, 7:46 p.m. UTC | #1
Quoting Heiko Stübner (2013-12-13 04:59:36)
> This adds a driver for controlling the external clock outputs of
> s3c24xx architectures including the dclk muxes and dividers.
> 
> Signed-off-by: Heiko Stuebner <heiko@sntech.de>

Acked-by: Mike Turquette <mturquette@linaro.org>

> ---
>  drivers/clk/samsung/Makefile                     |    1 +
>  drivers/clk/samsung/clk-s3c2410-dclk.c           |  517 ++++++++++++++++++++++
>  include/dt-bindings/clock/samsung,s3c2410-dclk.h |   28 ++
>  3 files changed, 546 insertions(+)
>  create mode 100644 drivers/clk/samsung/clk-s3c2410-dclk.c
>  create mode 100644 include/dt-bindings/clock/samsung,s3c2410-dclk.h
> 
> diff --git a/drivers/clk/samsung/Makefile b/drivers/clk/samsung/Makefile
> index 4c892c6..568683c 100644
> --- a/drivers/clk/samsung/Makefile
> +++ b/drivers/clk/samsung/Makefile
> @@ -8,5 +8,6 @@ obj-$(CONFIG_SOC_EXYNOS5250)    += clk-exynos5250.o
>  obj-$(CONFIG_SOC_EXYNOS5420)   += clk-exynos5420.o
>  obj-$(CONFIG_SOC_EXYNOS5440)   += clk-exynos5440.o
>  obj-$(CONFIG_ARCH_EXYNOS)      += clk-exynos-audss.o
> +obj-$(CONFIG_S3C2410_COMMON_DCLK)+= clk-s3c2410-dclk.o
>  obj-$(CONFIG_S3C2443_COMMON_CLK)+= clk-s3c2443.o
>  obj-$(CONFIG_ARCH_S3C64XX)     += clk-s3c64xx.o
> diff --git a/drivers/clk/samsung/clk-s3c2410-dclk.c b/drivers/clk/samsung/clk-s3c2410-dclk.c
> new file mode 100644
> index 0000000..de10e5c
> --- /dev/null
> +++ b/drivers/clk/samsung/clk-s3c2410-dclk.c
> @@ -0,0 +1,517 @@
> +/*
> + * Copyright (c) 2013 Heiko Stuebner <heiko@sntech.de>
> + *
> + * 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.
> + *
> + * Common Clock Framework support for s3c24xx external clock output.
> + */
> +
> +#include <linux/platform_device.h>
> +#include <linux/module.h>
> +#include <linux/mfd/syscon.h>
> +#include <linux/clk-provider.h>
> +#include <linux/regmap.h>
> +#include <linux/of.h>
> +#include <dt-bindings/clock/samsung,s3c2410-dclk.h>
> +#include "clk.h"
> +
> +/* legacy access to misccr, until dt conversion is finished */
> +#include <mach/hardware.h>
> +#include <mach/regs-gpio.h>
> +
> +enum supported_socs {
> +       S3C2410,
> +       S3C2412,
> +       S3C2440,
> +       S3C2443,
> +};
> +
> +struct s3c24xx_dclk_drv_data {
> +       int cpu_type;
> +};
> +
> +/*
> + * Clock for output-parent selection in misccr
> + */
> +
> +struct s3c24xx_clkout {
> +       struct clk_hw           hw;
> +       struct regmap           *misccr;
> +       u32                     mask;
> +       u8                      shift;
> +};
> +
> +#define to_s3c24xx_clkout(_hw) container_of(_hw, struct s3c24xx_clkout, hw)
> +
> +static u8 s3c24xx_clkout_get_parent(struct clk_hw *hw)
> +{
> +       struct s3c24xx_clkout *clkout = to_s3c24xx_clkout(hw);
> +       int num_parents = __clk_get_num_parents(hw->clk);
> +       u32 val;
> +       int ret = 0;
> +
> +       if (clkout->misccr)
> +               ret = regmap_read(clkout->misccr, 0, &val);
> +       else
> +               val = readl_relaxed(S3C24XX_MISCCR) >> clkout->shift;
> +
> +       if (ret)
> +               return ret;
> +
> +       val >>= clkout->shift;
> +       val &= clkout->mask;
> +
> +       if (val >= num_parents)
> +               return -EINVAL;
> +
> +       return val;
> +}
> +
> +static int s3c24xx_clkout_set_parent(struct clk_hw *hw, u8 index)
> +{
> +       struct s3c24xx_clkout *clkout = to_s3c24xx_clkout(hw);
> +       int ret = 0;
> +
> +       if (clkout->misccr)
> +               ret = regmap_update_bits(clkout->misccr, 0,
> +                                        (clkout->mask << clkout->shift),
> +                                        (index << clkout->shift));
> +       else
> +               s3c2410_modify_misccr((clkout->mask << clkout->shift),
> +                                     (index << clkout->shift));
> +
> +       return ret;
> +}
> +
> +const struct clk_ops s3c24xx_clkout_ops = {
> +       .get_parent = s3c24xx_clkout_get_parent,
> +       .set_parent = s3c24xx_clkout_set_parent,
> +       .determine_rate = __clk_mux_determine_rate,
> +};
> +
> +struct clk *s3c24xx_register_clkout(struct device *dev, const char *name,
> +               const char **parent_names, u8 num_parents,
> +               struct regmap *misccr, u8 shift, u32 mask)
> +{
> +       struct s3c24xx_clkout *clkout;
> +       struct clk *clk;
> +       struct clk_init_data init;
> +
> +       /* allocate the clkout */
> +       clkout = kzalloc(sizeof(*clkout), GFP_KERNEL);
> +       if (!clkout)
> +               return ERR_PTR(-ENOMEM);
> +
> +       init.name = name;
> +       init.ops = &s3c24xx_clkout_ops;
> +       init.flags = CLK_IS_BASIC;
> +       init.parent_names = parent_names;
> +       init.num_parents = num_parents;
> +
> +       clkout->misccr = misccr;
> +       clkout->shift = shift;
> +       clkout->mask = mask;
> +       clkout->hw.init = &init;
> +
> +       clk = clk_register(dev, &clkout->hw);
> +
> +       return clk;
> +}
> +
> +/*
> + * dclk and clkout init
> + */
> +
> +struct s3c24xx_dclk {
> +       struct device *dev;
> +       void __iomem *base;
> +       struct clk_onecell_data clk_data;
> +       struct notifier_block dclk0_div_change_nb;
> +       struct notifier_block dclk1_div_change_nb;
> +       spinlock_t dclk_lock;
> +       unsigned long reg_save;
> +};
> +
> +#define to_s3c24xx_dclk0(x) \
> +               container_of(x, struct s3c24xx_dclk, dclk0_div_change_nb)
> +
> +#define to_s3c24xx_dclk1(x) \
> +               container_of(x, struct s3c24xx_dclk, dclk1_div_change_nb)
> +
> +static const char dummy_nm[] __initconst = "dummy_name";
> +
> +PNAME(dclk_s3c2410_p) = { "pclk", "uclk" };
> +PNAME(clkout0_s3c2410_p) = { "mpll", "upll", "fclk", "hclk", "pclk",
> +                            "gate_dclk0" };
> +PNAME(clkout1_s3c2410_p) = { "mpll", "upll", "fclk", "hclk", "pclk",
> +                            "gate_dclk1" };
> +
> +PNAME(clkout0_s3c2412_p) = { "mpll", "upll", dummy_nm /* rtc clock output */,
> +                            "hclk", "pclk", "gate_dclk0" };
> +PNAME(clkout1_s3c2412_p) = { "xti", "upll", "fclk", "hclk", "pclk",
> +                            "gate_dclk1" };
> +
> +PNAME(clkout0_s3c2440_p) = { "xti", "upll", "fclk", "hclk", "pclk",
> +                            "gate_dclk0" };
> +PNAME(clkout1_s3c2440_p) = { "mpll", "upll", dummy_nm /* rtc clock output */,
> +                            "hclk", "pclk", "gate_dclk1" };
> +
> +PNAME(dclk_s3c2443_p) = { "pclk", "epll" };
> +PNAME(clkout0_s3c2443_p) = { "xti", "epll", "armclk", "hclk", "pclk",
> +                            "gate_dclk0" };
> +PNAME(clkout1_s3c2443_p) = { dummy_nm, "epll", dummy_nm /* rtc clock output */,
> +                            "hclk", "pclk", "gate_dclk1" };
> +
> +#define DCLKCON_DCLK_DIV_MASK          0xf
> +#define DCLKCON_DCLK0_DIV_SHIFT                4
> +#define DCLKCON_DCLK0_CMP_SHIFT                8
> +#define DCLKCON_DCLK1_DIV_SHIFT                20
> +#define DCLKCON_DCLK1_CMP_SHIFT                24
> +
> +static void s3c24xx_dclk_update_cmp(struct s3c24xx_dclk *s3c24xx_dclk,
> +                                   int div_shift, int cmp_shift)
> +{
> +       unsigned long flags = 0;
> +       u32 dclk_con, div, cmp;
> +
> +       spin_lock_irqsave(&s3c24xx_dclk->dclk_lock, flags);
> +
> +       dclk_con = readl_relaxed(s3c24xx_dclk->base);
> +
> +       div = ((dclk_con >> div_shift) & DCLKCON_DCLK_DIV_MASK) + 1;
> +       cmp = ((div + 1) / 2) - 1;
> +
> +       dclk_con &= ~(DCLKCON_DCLK_DIV_MASK << cmp_shift);
> +       dclk_con |= (cmp << cmp_shift);
> +
> +       writel_relaxed(dclk_con, s3c24xx_dclk->base);
> +
> +       spin_unlock_irqrestore(&s3c24xx_dclk->dclk_lock, flags);
> +}
> +
> +static int s3c24xx_dclk0_div_notify(struct notifier_block *nb,
> +                              unsigned long event, void *data)
> +{
> +       struct s3c24xx_dclk *s3c24xx_dclk = to_s3c24xx_dclk0(nb);
> +
> +       if (event == POST_RATE_CHANGE) {
> +               s3c24xx_dclk_update_cmp(s3c24xx_dclk,
> +                       DCLKCON_DCLK0_DIV_SHIFT, DCLKCON_DCLK0_CMP_SHIFT);
> +       }
> +
> +       return NOTIFY_DONE;
> +}
> +
> +static int s3c24xx_dclk1_div_notify(struct notifier_block *nb,
> +                              unsigned long event, void *data)
> +{
> +       struct s3c24xx_dclk *s3c24xx_dclk = to_s3c24xx_dclk1(nb);
> +
> +       if (event == POST_RATE_CHANGE) {
> +               s3c24xx_dclk_update_cmp(s3c24xx_dclk,
> +                       DCLKCON_DCLK1_DIV_SHIFT, DCLKCON_DCLK1_CMP_SHIFT);
> +       }
> +
> +       return NOTIFY_DONE;
> +}
> +
> +#ifdef CONFIG_PM_SLEEP
> +static int s3c24xx_dclk_suspend(struct device *dev)
> +{
> +       struct platform_device *pdev = to_platform_device(dev);
> +       struct s3c24xx_dclk *s3c24xx_dclk = platform_get_drvdata(pdev);
> +
> +       s3c24xx_dclk->reg_save = readl_relaxed(s3c24xx_dclk->base);
> +       return 0;
> +}
> +
> +static int s3c24xx_dclk_resume(struct device *dev)
> +{
> +       struct platform_device *pdev = to_platform_device(dev);
> +       struct s3c24xx_dclk *s3c24xx_dclk = platform_get_drvdata(pdev);
> +
> +       writel_relaxed(s3c24xx_dclk->reg_save, s3c24xx_dclk->base);
> +       return 0;
> +}
> +#endif
> +
> +static SIMPLE_DEV_PM_OPS(s3c24xx_dclk_pm_ops,
> +                        s3c24xx_dclk_suspend, s3c24xx_dclk_resume);
> +
> +static const struct of_device_id s3c24xx_dclk_dt_match[];
> +
> +static inline int s3c24xx_dclk_get_driver_data(struct platform_device *pdev)
> +{
> +       struct s3c24xx_dclk_drv_data *data;
> +       if (IS_ENABLED(CONFIG_OF) && pdev->dev.of_node) {
> +               const struct of_device_id *match;
> +               match = of_match_node(s3c24xx_dclk_dt_match, pdev->dev.of_node);
> +               data = (struct s3c24xx_dclk_drv_data *) match->data;
> +               return data->cpu_type;
> +       }
> +
> +       return platform_get_device_id(pdev)->driver_data;
> +}
> +
> +static int s3c24xx_dclk_probe(struct platform_device *pdev)
> +{
> +       struct s3c24xx_dclk *s3c24xx_dclk;
> +       struct device_node *np = pdev->dev.of_node;
> +       struct regmap *misccr = NULL;
> +       struct resource *mem;
> +       struct clk **clk_table;
> +       const char **clkout0_parent_names, **clkout1_parent_names;
> +       u8 clkout0_num_parents, clkout1_num_parents;
> +       int current_soc, ret, i;
> +
> +       s3c24xx_dclk = devm_kzalloc(&pdev->dev, sizeof(*s3c24xx_dclk),
> +                                   GFP_KERNEL);
> +       if (!s3c24xx_dclk)
> +               return -ENOMEM;
> +
> +       s3c24xx_dclk->dev = &pdev->dev;
> +       platform_set_drvdata(pdev, s3c24xx_dclk);
> +       spin_lock_init(&s3c24xx_dclk->dclk_lock);
> +
> +       clk_table = devm_kzalloc(&pdev->dev,
> +                                sizeof(struct clk *) * DCLK_MAX_CLKS,
> +                                GFP_KERNEL);
> +       if (!clk_table)
> +               return -ENOMEM;
> +
> +       s3c24xx_dclk->clk_data.clks = clk_table;
> +       s3c24xx_dclk->clk_data.clk_num = DCLK_MAX_CLKS;
> +
> +       mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +       s3c24xx_dclk->base = devm_ioremap_resource(&pdev->dev, mem);
> +       if (IS_ERR(s3c24xx_dclk->base))
> +               return PTR_ERR(s3c24xx_dclk->base);
> +
> +       /* when run from devicetree, get the misccr through a syscon-regmap */
> +       if (np) {
> +               misccr = syscon_regmap_lookup_by_phandle(np, "samsung,misccr");
> +               if (IS_ERR(misccr)) {
> +                       dev_err(&pdev->dev, "could not get misccr syscon, %ld\n",
> +                               PTR_ERR(misccr));
> +                       return PTR_ERR(misccr);
> +               }
> +       }
> +
> +       current_soc = s3c24xx_dclk_get_driver_data(pdev);
> +
> +       if (current_soc == S3C2443) {
> +               clk_table[MUX_DCLK0] = clk_register_mux(&pdev->dev,
> +                                       "mux_dclk0", dclk_s3c2443_p,
> +                                       ARRAY_SIZE(dclk_s3c2443_p), 0,
> +                                       s3c24xx_dclk->base, 1, 1, 0,
> +                                       &s3c24xx_dclk->dclk_lock);
> +               clk_table[MUX_DCLK1] = clk_register_mux(&pdev->dev,
> +                                       "mux_dclk1", dclk_s3c2443_p,
> +                                       ARRAY_SIZE(dclk_s3c2443_p), 0,
> +                                       s3c24xx_dclk->base, 17, 1, 0,
> +                                       &s3c24xx_dclk->dclk_lock);
> +       } else {
> +               clk_table[MUX_DCLK0] = clk_register_mux(&pdev->dev,
> +                                       "mux_dclk0", dclk_s3c2410_p,
> +                                       ARRAY_SIZE(dclk_s3c2410_p), 0,
> +                                       s3c24xx_dclk->base, 1, 1, 0,
> +                                       &s3c24xx_dclk->dclk_lock);
> +               clk_table[MUX_DCLK1] = clk_register_mux(&pdev->dev,
> +                                       "mux_dclk1", dclk_s3c2410_p,
> +                                       ARRAY_SIZE(dclk_s3c2410_p), 0,
> +                                       s3c24xx_dclk->base, 17, 1, 0,
> +                                       &s3c24xx_dclk->dclk_lock);
> +       }
> +
> +       clk_table[DIV_DCLK0] = clk_register_divider(&pdev->dev, "div_dclk0",
> +                                       "mux_dclk0", 0, s3c24xx_dclk->base,
> +                                       4, 4, 0, &s3c24xx_dclk->dclk_lock);
> +       clk_table[DIV_DCLK1] = clk_register_divider(&pdev->dev, "div_dclk1",
> +                                       "mux_dclk1", 0, s3c24xx_dclk->base,
> +                                       20, 4, 0, &s3c24xx_dclk->dclk_lock);
> +
> +       clk_table[GATE_DCLK0] = clk_register_gate(&pdev->dev, "gate_dclk0",
> +                                       "div_dclk0", CLK_SET_RATE_PARENT,
> +                                       s3c24xx_dclk->base, 0, 0,
> +                                       &s3c24xx_dclk->dclk_lock);
> +       clk_table[GATE_DCLK1] = clk_register_gate(&pdev->dev, "gate_dclk1",
> +                                       "div_dclk1", CLK_SET_RATE_PARENT,
> +                                       s3c24xx_dclk->base, 16, 0,
> +                                       &s3c24xx_dclk->dclk_lock);
> +
> +       switch (current_soc) {
> +       case S3C2410:
> +               clkout0_parent_names = clkout0_s3c2410_p;
> +               clkout0_num_parents = ARRAY_SIZE(clkout0_s3c2410_p);
> +               clkout1_parent_names = clkout1_s3c2410_p;
> +               clkout1_num_parents = ARRAY_SIZE(clkout1_s3c2410_p);
> +               break;
> +       case S3C2412:
> +               clkout0_parent_names = clkout0_s3c2412_p;
> +               clkout0_num_parents = ARRAY_SIZE(clkout0_s3c2412_p);
> +               clkout1_parent_names = clkout1_s3c2412_p;
> +               clkout1_num_parents = ARRAY_SIZE(clkout1_s3c2412_p);
> +               break;
> +       case S3C2440:
> +               clkout0_parent_names = clkout0_s3c2440_p;
> +               clkout0_num_parents = ARRAY_SIZE(clkout0_s3c2440_p);
> +               clkout1_parent_names = clkout1_s3c2440_p;
> +               clkout1_num_parents = ARRAY_SIZE(clkout1_s3c2440_p);
> +               break;
> +       case S3C2443:
> +               clkout0_parent_names = clkout0_s3c2443_p;
> +               clkout0_num_parents = ARRAY_SIZE(clkout0_s3c2443_p);
> +               clkout1_parent_names = clkout1_s3c2443_p;
> +               clkout1_num_parents = ARRAY_SIZE(clkout1_s3c2443_p);
> +               break;
> +       default:
> +               dev_err(&pdev->dev, "unsupported soc %d\n", current_soc);
> +               ret = -EINVAL;
> +               goto err_clk_register;
> +       }
> +
> +       clk_table[MUX_CLKOUT0] = s3c24xx_register_clkout(&pdev->dev,
> +                               "clkout0", clkout0_parent_names,
> +                               clkout0_num_parents, misccr, 4, 7);
> +       clk_table[MUX_CLKOUT1] = s3c24xx_register_clkout(&pdev->dev, "clkout1",
> +                               clkout1_parent_names,
> +                               clkout1_num_parents, misccr, 8, 7);
> +
> +       for (i = 0; i < DCLK_MAX_CLKS; i++)
> +               if (IS_ERR(clk_table[i])) {
> +                       dev_err(&pdev->dev, "clock %d failed to register\n", i);
> +                       ret = PTR_ERR(clk_table[i]);
> +                       goto err_clk_register;
> +               }
> +
> +       ret = clk_register_clkdev(clk_table[MUX_DCLK0], "dclk0", NULL);
> +       ret |= clk_register_clkdev(clk_table[MUX_DCLK1], "dclk1", NULL);
> +       ret |= clk_register_clkdev(clk_table[MUX_CLKOUT0], "clkout0", NULL);
> +       ret |= clk_register_clkdev(clk_table[MUX_CLKOUT1], "clkout1", NULL);
> +       if (ret) {
> +               dev_err(&pdev->dev, "failed to register aliases\n");
> +               goto err_clk_register;
> +       }
> +
> +       s3c24xx_dclk->dclk0_div_change_nb.notifier_call =
> +                                               s3c24xx_dclk0_div_notify;
> +       s3c24xx_dclk->dclk0_div_change_nb.next = NULL;
> +
> +       s3c24xx_dclk->dclk1_div_change_nb.notifier_call =
> +                                               s3c24xx_dclk1_div_notify;
> +       s3c24xx_dclk->dclk1_div_change_nb.next = NULL;
> +
> +       ret = clk_notifier_register(clk_table[DIV_DCLK0],
> +                                   &s3c24xx_dclk->dclk0_div_change_nb);
> +       if (ret)
> +               goto err_clk_register;
> +
> +       ret = clk_notifier_register(clk_table[DIV_DCLK1],
> +                                   &s3c24xx_dclk->dclk1_div_change_nb);
> +       if (ret)
> +               goto err_dclk_notify;
> +
> +       if (np) {
> +               ret = of_clk_add_provider(np,
> +                             of_clk_src_onecell_get, &s3c24xx_dclk->clk_data);
> +               if (ret)
> +                       goto err_of_clk_provider;
> +       }
> +
> +       return 0;
> +
> +err_of_clk_provider:
> +       clk_notifier_unregister(clk_table[DIV_DCLK1],
> +                               &s3c24xx_dclk->dclk1_div_change_nb);
> +err_dclk_notify:
> +       clk_notifier_unregister(clk_table[DIV_DCLK0],
> +                               &s3c24xx_dclk->dclk0_div_change_nb);
> +err_clk_register:
> +       for (i = 0; i < DCLK_MAX_CLKS; i++)
> +               if (clk_table[i] && !IS_ERR(clk_table[i]))
> +                       clk_unregister(clk_table[i]);
> +
> +       return ret;
> +}
> +
> +static int s3c24xx_dclk_remove(struct platform_device *pdev)
> +{
> +       struct s3c24xx_dclk *s3c24xx_dclk = platform_get_drvdata(pdev);
> +       struct clk **clk_table = s3c24xx_dclk->clk_data.clks;
> +       int i;
> +
> +       of_clk_del_provider(pdev->dev.of_node);
> +
> +       clk_notifier_unregister(clk_table[DIV_DCLK1],
> +                               &s3c24xx_dclk->dclk1_div_change_nb);
> +       clk_notifier_unregister(clk_table[DIV_DCLK0],
> +                               &s3c24xx_dclk->dclk0_div_change_nb);
> +
> +       for (i = 0; i < DCLK_MAX_CLKS; i++)
> +               clk_unregister(clk_table[i]);
> +
> +       return 0;
> +}
> +
> +static struct s3c24xx_dclk_drv_data s3c24xx_dclk_drv_data_array[] = {
> +       [S3C2410] = { S3C2410 },
> +       [S3C2412] = { S3C2412 },
> +       [S3C2440] = { S3C2440 },
> +       [S3C2443] = { S3C2443 },
> +};
> +
> +static const struct of_device_id s3c24xx_dclk_dt_match[] = {
> +       {
> +               .compatible = "samsung,s3c2410-dclk",
> +               .data = &s3c24xx_dclk_drv_data_array[S3C2410],
> +       }, {
> +               .compatible = "samsung,s3c2412-dclk",
> +               .data = &s3c24xx_dclk_drv_data_array[S3C2412],
> +       }, {
> +               .compatible = "samsung,s3c2440-dclk",
> +               .data = &s3c24xx_dclk_drv_data_array[S3C2440],
> +       }, {
> +               .compatible = "samsung,s3c2443-dclk",
> +               .data = &s3c24xx_dclk_drv_data_array[S3C2443],
> +       },
> +       { },
> +};
> +MODULE_DEVICE_TABLE(of, s3c24xx_dclk_dt_match);
> +
> +static struct platform_device_id s3c24xx_dclk_driver_ids[] = {
> +       {
> +               .name           = "s3c2410-dclk",
> +               .driver_data    = S3C2410,
> +       }, {
> +               .name           = "s3c2412-dclk",
> +               .driver_data    = S3C2412,
> +       }, {
> +               .name           = "s3c2440-dclk",
> +               .driver_data    = S3C2440,
> +       }, {
> +               .name           = "s3c2443-dclk",
> +               .driver_data    = S3C2443,
> +       },
> +       { }
> +};
> +
> +MODULE_DEVICE_TABLE(platform, s3c24xx_dclk_driver_ids);
> +
> +static struct platform_driver s3c24xx_dclk_driver = {
> +       .driver = {
> +               .name           = "s3c24xx-dclk",
> +               .owner          = THIS_MODULE,
> +               .pm             = &s3c24xx_dclk_pm_ops,
> +               .of_match_table = of_match_ptr(s3c24xx_dclk_dt_match),
> +       },
> +       .probe = s3c24xx_dclk_probe,
> +       .remove = s3c24xx_dclk_remove,
> +       .id_table = s3c24xx_dclk_driver_ids,
> +};
> +module_platform_driver(s3c24xx_dclk_driver);
> +
> +MODULE_LICENSE("GPL v2");
> +MODULE_AUTHOR("Heiko Stuebner <heiko@sntech.de>");
> +MODULE_DESCRIPTION("Driver for the S3C24XX external clock outputs");
> diff --git a/include/dt-bindings/clock/samsung,s3c2410-dclk.h b/include/dt-bindings/clock/samsung,s3c2410-dclk.h
> new file mode 100644
> index 0000000..7394d46
> --- /dev/null
> +++ b/include/dt-bindings/clock/samsung,s3c2410-dclk.h
> @@ -0,0 +1,28 @@
> +/*
> + * Copyright (c) 2013 Heiko Stuebner <heiko@sntech.de>
> + *
> + * 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.
> + *
> + * Device Tree binding constants clock controllers of Samsung S3C2410 and later.
> + */
> +
> +#ifndef _DT_BINDINGS_CLOCK_SAMSUNG_S3C2410_CLOCK_H
> +#define _DT_BINDINGS_CLOCK_SAMSUNG_S3C2410_CLOCK_H
> +
> +#define MUX_DCLK0      0
> +#define MUX_DCLK1      1
> +
> +#define DIV_DCLK0      2
> +#define DIV_DCLK1      3
> +
> +#define GATE_DCLK0     4
> +#define GATE_DCLK1     5
> +
> +#define MUX_CLKOUT0    6
> +#define MUX_CLKOUT1    7
> +
> +#define DCLK_MAX_CLKS  (MUX_CLKOUT1 + 1)
> +
> +#endif
> -- 
> 1.7.10.4
> 
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Tomasz Figa Feb. 9, 2014, 2:25 a.m. UTC | #2
Hi Heiko,

On 13.12.2013 13:59, Heiko Stübner wrote:
> This adds a driver for controlling the external clock outputs of
> s3c24xx architectures including the dclk muxes and dividers.
>
> Signed-off-by: Heiko Stuebner <heiko@sntech.de>
> ---
>   drivers/clk/samsung/Makefile                     |    1 +
>   drivers/clk/samsung/clk-s3c2410-dclk.c           |  517 ++++++++++++++++++++++
>   include/dt-bindings/clock/samsung,s3c2410-dclk.h |   28 ++
>   3 files changed, 546 insertions(+)
>   create mode 100644 drivers/clk/samsung/clk-s3c2410-dclk.c
>   create mode 100644 include/dt-bindings/clock/samsung,s3c2410-dclk.h
>
> diff --git a/drivers/clk/samsung/Makefile b/drivers/clk/samsung/Makefile
> index 4c892c6..568683c 100644
> --- a/drivers/clk/samsung/Makefile
> +++ b/drivers/clk/samsung/Makefile
> @@ -8,5 +8,6 @@ obj-$(CONFIG_SOC_EXYNOS5250)	+= clk-exynos5250.o
>   obj-$(CONFIG_SOC_EXYNOS5420)	+= clk-exynos5420.o
>   obj-$(CONFIG_SOC_EXYNOS5440)	+= clk-exynos5440.o
>   obj-$(CONFIG_ARCH_EXYNOS)	+= clk-exynos-audss.o
> +obj-$(CONFIG_S3C2410_COMMON_DCLK)+= clk-s3c2410-dclk.o
>   obj-$(CONFIG_S3C2443_COMMON_CLK)+= clk-s3c2443.o
>   obj-$(CONFIG_ARCH_S3C64XX)	+= clk-s3c64xx.o
> diff --git a/drivers/clk/samsung/clk-s3c2410-dclk.c b/drivers/clk/samsung/clk-s3c2410-dclk.c
> new file mode 100644
> index 0000000..de10e5c
> --- /dev/null
> +++ b/drivers/clk/samsung/clk-s3c2410-dclk.c
> @@ -0,0 +1,517 @@
> +/*
> + * Copyright (c) 2013 Heiko Stuebner <heiko@sntech.de>
> + *
> + * 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.
> + *
> + * Common Clock Framework support for s3c24xx external clock output.
> + */
> +
> +#include <linux/platform_device.h>
> +#include <linux/module.h>
> +#include <linux/mfd/syscon.h>
> +#include <linux/clk-provider.h>
> +#include <linux/regmap.h>
> +#include <linux/of.h>
> +#include <dt-bindings/clock/samsung,s3c2410-dclk.h>
> +#include "clk.h"
> +
> +/* legacy access to misccr, until dt conversion is finished */
> +#include <mach/hardware.h>
> +#include <mach/regs-gpio.h>
> +
> +enum supported_socs {
> +	S3C2410,
> +	S3C2412,
> +	S3C2440,
> +	S3C2443,
> +};
> +
> +struct s3c24xx_dclk_drv_data {
> +	int cpu_type;
> +};
> +
> +/*
> + * Clock for output-parent selection in misccr
> + */
> +
> +struct s3c24xx_clkout {
> +	struct clk_hw		hw;
> +	struct regmap		*misccr;
> +	u32			mask;
> +	u8			shift;
> +};
> +
> +#define to_s3c24xx_clkout(_hw) container_of(_hw, struct s3c24xx_clkout, hw)
> +
> +static u8 s3c24xx_clkout_get_parent(struct clk_hw *hw)
> +{
> +	struct s3c24xx_clkout *clkout = to_s3c24xx_clkout(hw);
> +	int num_parents = __clk_get_num_parents(hw->clk);
> +	u32 val;
> +	int ret = 0;
> +
> +	if (clkout->misccr)
> +		ret = regmap_read(clkout->misccr, 0, &val);
> +	else
> +		val = readl_relaxed(S3C24XX_MISCCR) >> clkout->shift;

I wonder if this couldn't be simplified by always providing a regmap.

> +
> +	if (ret)
> +		return ret;
> +
> +	val >>= clkout->shift;
> +	val &= clkout->mask;
> +
> +	if (val >= num_parents)
> +		return -EINVAL;
> +
> +	return val;
> +}

[snip]

> +#define to_s3c24xx_dclk0(x) \
> +		container_of(x, struct s3c24xx_dclk, dclk0_div_change_nb)
> +
> +#define to_s3c24xx_dclk1(x) \
> +		container_of(x, struct s3c24xx_dclk, dclk1_div_change_nb)
> +
> +static const char dummy_nm[] __initconst = "dummy_name";

What's the advantage of having it defined this way instead of using 
"dummy_name" (or probably "reserved" or "none", as in Samsung clock 
drivers) directly in parent lists?

> +
> +PNAME(dclk_s3c2410_p) = { "pclk", "uclk" };
> +PNAME(clkout0_s3c2410_p) = { "mpll", "upll", "fclk", "hclk", "pclk",
> +			     "gate_dclk0" };
> +PNAME(clkout1_s3c2410_p) = { "mpll", "upll", "fclk", "hclk", "pclk",
> +			     "gate_dclk1" };
> +
> +PNAME(clkout0_s3c2412_p) = { "mpll", "upll", dummy_nm /* rtc clock output */,
> +			     "hclk", "pclk", "gate_dclk0" };

Hmm, this would suggest that instead of dummy_nm, a real name should be 
used here, even if such clock doesn't exist yet. CCF will handle this fine.

> +PNAME(clkout1_s3c2412_p) = { "xti", "upll", "fclk", "hclk", "pclk",
> +			     "gate_dclk1" };
> +
> +PNAME(clkout0_s3c2440_p) = { "xti", "upll", "fclk", "hclk", "pclk",
> +			     "gate_dclk0" };
> +PNAME(clkout1_s3c2440_p) = { "mpll", "upll", dummy_nm /* rtc clock output */,
> +			     "hclk", "pclk", "gate_dclk1" };

[snip]

> +static int s3c24xx_dclk_probe(struct platform_device *pdev)
> +{
> +	struct s3c24xx_dclk *s3c24xx_dclk;
> +	struct device_node *np = pdev->dev.of_node;
> +	struct regmap *misccr = NULL;
> +	struct resource *mem;
> +	struct clk **clk_table;
> +	const char **clkout0_parent_names, **clkout1_parent_names;
> +	u8 clkout0_num_parents, clkout1_num_parents;
> +	int current_soc, ret, i;
> +
> +	s3c24xx_dclk = devm_kzalloc(&pdev->dev, sizeof(*s3c24xx_dclk),
> +				    GFP_KERNEL);
> +	if (!s3c24xx_dclk)
> +		return -ENOMEM;
> +
> +	s3c24xx_dclk->dev = &pdev->dev;
> +	platform_set_drvdata(pdev, s3c24xx_dclk);
> +	spin_lock_init(&s3c24xx_dclk->dclk_lock);
> +
> +	clk_table = devm_kzalloc(&pdev->dev,
> +				 sizeof(struct clk *) * DCLK_MAX_CLKS,
> +				 GFP_KERNEL);
> +	if (!clk_table)
> +		return -ENOMEM;
> +
> +	s3c24xx_dclk->clk_data.clks = clk_table;
> +	s3c24xx_dclk->clk_data.clk_num = DCLK_MAX_CLKS;
> +
> +	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +	s3c24xx_dclk->base = devm_ioremap_resource(&pdev->dev, mem);
> +	if (IS_ERR(s3c24xx_dclk->base))
> +		return PTR_ERR(s3c24xx_dclk->base);
> +
> +	/* when run from devicetree, get the misccr through a syscon-regmap */
> +	if (np) {
> +		misccr = syscon_regmap_lookup_by_phandle(np, "samsung,misccr");
> +		if (IS_ERR(misccr)) {
> +			dev_err(&pdev->dev, "could not get misccr syscon, %ld\n",
> +				PTR_ERR(misccr));
> +			return PTR_ERR(misccr);
> +		}
> +	}
> +
> +	current_soc = s3c24xx_dclk_get_driver_data(pdev);
> +
> +	if (current_soc == S3C2443) {
> +		clk_table[MUX_DCLK0] = clk_register_mux(&pdev->dev,
> +					"mux_dclk0", dclk_s3c2443_p,
> +					ARRAY_SIZE(dclk_s3c2443_p), 0,
> +					s3c24xx_dclk->base, 1, 1, 0,
> +					&s3c24xx_dclk->dclk_lock);
> +		clk_table[MUX_DCLK1] = clk_register_mux(&pdev->dev,
> +					"mux_dclk1", dclk_s3c2443_p,
> +					ARRAY_SIZE(dclk_s3c2443_p), 0,
> +					s3c24xx_dclk->base, 17, 1, 0,
> +					&s3c24xx_dclk->dclk_lock);
> +	} else {
> +		clk_table[MUX_DCLK0] = clk_register_mux(&pdev->dev,
> +					"mux_dclk0", dclk_s3c2410_p,
> +					ARRAY_SIZE(dclk_s3c2410_p), 0,
> +					s3c24xx_dclk->base, 1, 1, 0,
> +					&s3c24xx_dclk->dclk_lock);
> +		clk_table[MUX_DCLK1] = clk_register_mux(&pdev->dev,
> +					"mux_dclk1", dclk_s3c2410_p,
> +					ARRAY_SIZE(dclk_s3c2410_p), 0,
> +					s3c24xx_dclk->base, 17, 1, 0,
> +					&s3c24xx_dclk->dclk_lock);
> +	}

What about using a variant struct instead? Match tables would simply 
contain pointers to respective structs and here the code would refer to 
appropriate fields in a struct returned by s3c24xx_dclk_get_driver_data().

> +
> +	clk_table[DIV_DCLK0] = clk_register_divider(&pdev->dev, "div_dclk0",
> +					"mux_dclk0", 0, s3c24xx_dclk->base,
> +					4, 4, 0, &s3c24xx_dclk->dclk_lock);
> +	clk_table[DIV_DCLK1] = clk_register_divider(&pdev->dev, "div_dclk1",
> +					"mux_dclk1", 0, s3c24xx_dclk->base,
> +					20, 4, 0, &s3c24xx_dclk->dclk_lock);
> +
> +	clk_table[GATE_DCLK0] = clk_register_gate(&pdev->dev, "gate_dclk0",
> +					"div_dclk0", CLK_SET_RATE_PARENT,
> +					s3c24xx_dclk->base, 0, 0,
> +					&s3c24xx_dclk->dclk_lock);
> +	clk_table[GATE_DCLK1] = clk_register_gate(&pdev->dev, "gate_dclk1",
> +					"div_dclk1", CLK_SET_RATE_PARENT,
> +					s3c24xx_dclk->base, 16, 0,
> +					&s3c24xx_dclk->dclk_lock);
> +
> +	switch (current_soc) {
> +	case S3C2410:
> +		clkout0_parent_names = clkout0_s3c2410_p;
> +		clkout0_num_parents = ARRAY_SIZE(clkout0_s3c2410_p);
> +		clkout1_parent_names = clkout1_s3c2410_p;
> +		clkout1_num_parents = ARRAY_SIZE(clkout1_s3c2410_p);
> +		break;
> +	case S3C2412:
> +		clkout0_parent_names = clkout0_s3c2412_p;
> +		clkout0_num_parents = ARRAY_SIZE(clkout0_s3c2412_p);
> +		clkout1_parent_names = clkout1_s3c2412_p;
> +		clkout1_num_parents = ARRAY_SIZE(clkout1_s3c2412_p);
> +		break;
> +	case S3C2440:
> +		clkout0_parent_names = clkout0_s3c2440_p;
> +		clkout0_num_parents = ARRAY_SIZE(clkout0_s3c2440_p);
> +		clkout1_parent_names = clkout1_s3c2440_p;
> +		clkout1_num_parents = ARRAY_SIZE(clkout1_s3c2440_p);
> +		break;
> +	case S3C2443:
> +		clkout0_parent_names = clkout0_s3c2443_p;
> +		clkout0_num_parents = ARRAY_SIZE(clkout0_s3c2443_p);
> +		clkout1_parent_names = clkout1_s3c2443_p;
> +		clkout1_num_parents = ARRAY_SIZE(clkout1_s3c2443_p);
> +		break;
> +	default:
> +		dev_err(&pdev->dev, "unsupported soc %d\n", current_soc);
> +		ret = -EINVAL;
> +		goto err_clk_register;
> +	}

Ditto.

> +
> +	clk_table[MUX_CLKOUT0] = s3c24xx_register_clkout(&pdev->dev,
> +				"clkout0", clkout0_parent_names,
> +				clkout0_num_parents, misccr, 4, 7);
> +	clk_table[MUX_CLKOUT1] = s3c24xx_register_clkout(&pdev->dev, "clkout1",
> +				clkout1_parent_names,
> +				clkout1_num_parents, misccr, 8, 7);
> +
> +	for (i = 0; i < DCLK_MAX_CLKS; i++)
> +		if (IS_ERR(clk_table[i])) {
> +			dev_err(&pdev->dev, "clock %d failed to register\n", i);
> +			ret = PTR_ERR(clk_table[i]);
> +			goto err_clk_register;
> +		}
> +
> +	ret = clk_register_clkdev(clk_table[MUX_DCLK0], "dclk0", NULL);
> +	ret |= clk_register_clkdev(clk_table[MUX_DCLK1], "dclk1", NULL);
> +	ret |= clk_register_clkdev(clk_table[MUX_CLKOUT0], "clkout0", NULL);
> +	ret |= clk_register_clkdev(clk_table[MUX_CLKOUT1], "clkout1", NULL);

Hmm, won't it break the error value if two calls return different error 
codes?

I guess that

if (!ret)
	ret = ...
if (!ret)
	ret = ...

construct would be more appropriate here, if you don't want error 
message per call.


> +	if (ret) {
> +		dev_err(&pdev->dev, "failed to register aliases\n");
> +		goto err_clk_register;
> +	}
> +
> +	s3c24xx_dclk->dclk0_div_change_nb.notifier_call =
> +						s3c24xx_dclk0_div_notify;
> +	s3c24xx_dclk->dclk0_div_change_nb.next = NULL;

Do you need to set this field to NULL explicitly?

Best regards,
Tomasz
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diff mbox

Patch

diff --git a/drivers/clk/samsung/Makefile b/drivers/clk/samsung/Makefile
index 4c892c6..568683c 100644
--- a/drivers/clk/samsung/Makefile
+++ b/drivers/clk/samsung/Makefile
@@ -8,5 +8,6 @@  obj-$(CONFIG_SOC_EXYNOS5250)	+= clk-exynos5250.o
 obj-$(CONFIG_SOC_EXYNOS5420)	+= clk-exynos5420.o
 obj-$(CONFIG_SOC_EXYNOS5440)	+= clk-exynos5440.o
 obj-$(CONFIG_ARCH_EXYNOS)	+= clk-exynos-audss.o
+obj-$(CONFIG_S3C2410_COMMON_DCLK)+= clk-s3c2410-dclk.o
 obj-$(CONFIG_S3C2443_COMMON_CLK)+= clk-s3c2443.o
 obj-$(CONFIG_ARCH_S3C64XX)	+= clk-s3c64xx.o
diff --git a/drivers/clk/samsung/clk-s3c2410-dclk.c b/drivers/clk/samsung/clk-s3c2410-dclk.c
new file mode 100644
index 0000000..de10e5c
--- /dev/null
+++ b/drivers/clk/samsung/clk-s3c2410-dclk.c
@@ -0,0 +1,517 @@ 
+/*
+ * Copyright (c) 2013 Heiko Stuebner <heiko@sntech.de>
+ *
+ * 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.
+ *
+ * Common Clock Framework support for s3c24xx external clock output.
+ */
+
+#include <linux/platform_device.h>
+#include <linux/module.h>
+#include <linux/mfd/syscon.h>
+#include <linux/clk-provider.h>
+#include <linux/regmap.h>
+#include <linux/of.h>
+#include <dt-bindings/clock/samsung,s3c2410-dclk.h>
+#include "clk.h"
+
+/* legacy access to misccr, until dt conversion is finished */
+#include <mach/hardware.h>
+#include <mach/regs-gpio.h>
+
+enum supported_socs {
+	S3C2410,
+	S3C2412,
+	S3C2440,
+	S3C2443,
+};
+
+struct s3c24xx_dclk_drv_data {
+	int cpu_type;
+};
+
+/*
+ * Clock for output-parent selection in misccr
+ */
+
+struct s3c24xx_clkout {
+	struct clk_hw		hw;
+	struct regmap		*misccr;
+	u32			mask;
+	u8			shift;
+};
+
+#define to_s3c24xx_clkout(_hw) container_of(_hw, struct s3c24xx_clkout, hw)
+
+static u8 s3c24xx_clkout_get_parent(struct clk_hw *hw)
+{
+	struct s3c24xx_clkout *clkout = to_s3c24xx_clkout(hw);
+	int num_parents = __clk_get_num_parents(hw->clk);
+	u32 val;
+	int ret = 0;
+
+	if (clkout->misccr)
+		ret = regmap_read(clkout->misccr, 0, &val);
+	else
+		val = readl_relaxed(S3C24XX_MISCCR) >> clkout->shift;
+
+	if (ret)
+		return ret;
+
+	val >>= clkout->shift;
+	val &= clkout->mask;
+
+	if (val >= num_parents)
+		return -EINVAL;
+
+	return val;
+}
+
+static int s3c24xx_clkout_set_parent(struct clk_hw *hw, u8 index)
+{
+	struct s3c24xx_clkout *clkout = to_s3c24xx_clkout(hw);
+	int ret = 0;
+
+	if (clkout->misccr)
+		ret = regmap_update_bits(clkout->misccr, 0,
+					 (clkout->mask << clkout->shift),
+					 (index << clkout->shift));
+	else
+		s3c2410_modify_misccr((clkout->mask << clkout->shift),
+				      (index << clkout->shift));
+
+	return ret;
+}
+
+const struct clk_ops s3c24xx_clkout_ops = {
+	.get_parent = s3c24xx_clkout_get_parent,
+	.set_parent = s3c24xx_clkout_set_parent,
+	.determine_rate = __clk_mux_determine_rate,
+};
+
+struct clk *s3c24xx_register_clkout(struct device *dev, const char *name,
+		const char **parent_names, u8 num_parents,
+		struct regmap *misccr, u8 shift, u32 mask)
+{
+	struct s3c24xx_clkout *clkout;
+	struct clk *clk;
+	struct clk_init_data init;
+
+	/* allocate the clkout */
+	clkout = kzalloc(sizeof(*clkout), GFP_KERNEL);
+	if (!clkout)
+		return ERR_PTR(-ENOMEM);
+
+	init.name = name;
+	init.ops = &s3c24xx_clkout_ops;
+	init.flags = CLK_IS_BASIC;
+	init.parent_names = parent_names;
+	init.num_parents = num_parents;
+
+	clkout->misccr = misccr;
+	clkout->shift = shift;
+	clkout->mask = mask;
+	clkout->hw.init = &init;
+
+	clk = clk_register(dev, &clkout->hw);
+
+	return clk;
+}
+
+/*
+ * dclk and clkout init
+ */
+
+struct s3c24xx_dclk {
+	struct device *dev;
+	void __iomem *base;
+	struct clk_onecell_data clk_data;
+	struct notifier_block dclk0_div_change_nb;
+	struct notifier_block dclk1_div_change_nb;
+	spinlock_t dclk_lock;
+	unsigned long reg_save;
+};
+
+#define to_s3c24xx_dclk0(x) \
+		container_of(x, struct s3c24xx_dclk, dclk0_div_change_nb)
+
+#define to_s3c24xx_dclk1(x) \
+		container_of(x, struct s3c24xx_dclk, dclk1_div_change_nb)
+
+static const char dummy_nm[] __initconst = "dummy_name";
+
+PNAME(dclk_s3c2410_p) = { "pclk", "uclk" };
+PNAME(clkout0_s3c2410_p) = { "mpll", "upll", "fclk", "hclk", "pclk",
+			     "gate_dclk0" };
+PNAME(clkout1_s3c2410_p) = { "mpll", "upll", "fclk", "hclk", "pclk",
+			     "gate_dclk1" };
+
+PNAME(clkout0_s3c2412_p) = { "mpll", "upll", dummy_nm /* rtc clock output */,
+			     "hclk", "pclk", "gate_dclk0" };
+PNAME(clkout1_s3c2412_p) = { "xti", "upll", "fclk", "hclk", "pclk",
+			     "gate_dclk1" };
+
+PNAME(clkout0_s3c2440_p) = { "xti", "upll", "fclk", "hclk", "pclk",
+			     "gate_dclk0" };
+PNAME(clkout1_s3c2440_p) = { "mpll", "upll", dummy_nm /* rtc clock output */,
+			     "hclk", "pclk", "gate_dclk1" };
+
+PNAME(dclk_s3c2443_p) = { "pclk", "epll" };
+PNAME(clkout0_s3c2443_p) = { "xti", "epll", "armclk", "hclk", "pclk",
+			     "gate_dclk0" };
+PNAME(clkout1_s3c2443_p) = { dummy_nm, "epll", dummy_nm /* rtc clock output */,
+			     "hclk", "pclk", "gate_dclk1" };
+
+#define DCLKCON_DCLK_DIV_MASK		0xf
+#define DCLKCON_DCLK0_DIV_SHIFT		4
+#define DCLKCON_DCLK0_CMP_SHIFT		8
+#define DCLKCON_DCLK1_DIV_SHIFT		20
+#define DCLKCON_DCLK1_CMP_SHIFT		24
+
+static void s3c24xx_dclk_update_cmp(struct s3c24xx_dclk *s3c24xx_dclk,
+				    int div_shift, int cmp_shift)
+{
+	unsigned long flags = 0;
+	u32 dclk_con, div, cmp;
+
+	spin_lock_irqsave(&s3c24xx_dclk->dclk_lock, flags);
+
+	dclk_con = readl_relaxed(s3c24xx_dclk->base);
+
+	div = ((dclk_con >> div_shift) & DCLKCON_DCLK_DIV_MASK) + 1;
+	cmp = ((div + 1) / 2) - 1;
+
+	dclk_con &= ~(DCLKCON_DCLK_DIV_MASK << cmp_shift);
+	dclk_con |= (cmp << cmp_shift);
+
+	writel_relaxed(dclk_con, s3c24xx_dclk->base);
+
+	spin_unlock_irqrestore(&s3c24xx_dclk->dclk_lock, flags);
+}
+
+static int s3c24xx_dclk0_div_notify(struct notifier_block *nb,
+			       unsigned long event, void *data)
+{
+	struct s3c24xx_dclk *s3c24xx_dclk = to_s3c24xx_dclk0(nb);
+
+	if (event == POST_RATE_CHANGE) {
+		s3c24xx_dclk_update_cmp(s3c24xx_dclk,
+			DCLKCON_DCLK0_DIV_SHIFT, DCLKCON_DCLK0_CMP_SHIFT);
+	}
+
+	return NOTIFY_DONE;
+}
+
+static int s3c24xx_dclk1_div_notify(struct notifier_block *nb,
+			       unsigned long event, void *data)
+{
+	struct s3c24xx_dclk *s3c24xx_dclk = to_s3c24xx_dclk1(nb);
+
+	if (event == POST_RATE_CHANGE) {
+		s3c24xx_dclk_update_cmp(s3c24xx_dclk,
+			DCLKCON_DCLK1_DIV_SHIFT, DCLKCON_DCLK1_CMP_SHIFT);
+	}
+
+	return NOTIFY_DONE;
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int s3c24xx_dclk_suspend(struct device *dev)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct s3c24xx_dclk *s3c24xx_dclk = platform_get_drvdata(pdev);
+
+	s3c24xx_dclk->reg_save = readl_relaxed(s3c24xx_dclk->base);
+	return 0;
+}
+
+static int s3c24xx_dclk_resume(struct device *dev)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct s3c24xx_dclk *s3c24xx_dclk = platform_get_drvdata(pdev);
+
+	writel_relaxed(s3c24xx_dclk->reg_save, s3c24xx_dclk->base);
+	return 0;
+}
+#endif
+
+static SIMPLE_DEV_PM_OPS(s3c24xx_dclk_pm_ops,
+			 s3c24xx_dclk_suspend, s3c24xx_dclk_resume);
+
+static const struct of_device_id s3c24xx_dclk_dt_match[];
+
+static inline int s3c24xx_dclk_get_driver_data(struct platform_device *pdev)
+{
+	struct s3c24xx_dclk_drv_data *data;
+	if (IS_ENABLED(CONFIG_OF) && pdev->dev.of_node) {
+		const struct of_device_id *match;
+		match = of_match_node(s3c24xx_dclk_dt_match, pdev->dev.of_node);
+		data = (struct s3c24xx_dclk_drv_data *) match->data;
+		return data->cpu_type;
+	}
+
+	return platform_get_device_id(pdev)->driver_data;
+}
+
+static int s3c24xx_dclk_probe(struct platform_device *pdev)
+{
+	struct s3c24xx_dclk *s3c24xx_dclk;
+	struct device_node *np = pdev->dev.of_node;
+	struct regmap *misccr = NULL;
+	struct resource *mem;
+	struct clk **clk_table;
+	const char **clkout0_parent_names, **clkout1_parent_names;
+	u8 clkout0_num_parents, clkout1_num_parents;
+	int current_soc, ret, i;
+
+	s3c24xx_dclk = devm_kzalloc(&pdev->dev, sizeof(*s3c24xx_dclk),
+				    GFP_KERNEL);
+	if (!s3c24xx_dclk)
+		return -ENOMEM;
+
+	s3c24xx_dclk->dev = &pdev->dev;
+	platform_set_drvdata(pdev, s3c24xx_dclk);
+	spin_lock_init(&s3c24xx_dclk->dclk_lock);
+
+	clk_table = devm_kzalloc(&pdev->dev,
+				 sizeof(struct clk *) * DCLK_MAX_CLKS,
+				 GFP_KERNEL);
+	if (!clk_table)
+		return -ENOMEM;
+
+	s3c24xx_dclk->clk_data.clks = clk_table;
+	s3c24xx_dclk->clk_data.clk_num = DCLK_MAX_CLKS;
+
+	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	s3c24xx_dclk->base = devm_ioremap_resource(&pdev->dev, mem);
+	if (IS_ERR(s3c24xx_dclk->base))
+		return PTR_ERR(s3c24xx_dclk->base);
+
+	/* when run from devicetree, get the misccr through a syscon-regmap */
+	if (np) {
+		misccr = syscon_regmap_lookup_by_phandle(np, "samsung,misccr");
+		if (IS_ERR(misccr)) {
+			dev_err(&pdev->dev, "could not get misccr syscon, %ld\n",
+				PTR_ERR(misccr));
+			return PTR_ERR(misccr);
+		}
+	}
+
+	current_soc = s3c24xx_dclk_get_driver_data(pdev);
+
+	if (current_soc == S3C2443) {
+		clk_table[MUX_DCLK0] = clk_register_mux(&pdev->dev,
+					"mux_dclk0", dclk_s3c2443_p,
+					ARRAY_SIZE(dclk_s3c2443_p), 0,
+					s3c24xx_dclk->base, 1, 1, 0,
+					&s3c24xx_dclk->dclk_lock);
+		clk_table[MUX_DCLK1] = clk_register_mux(&pdev->dev,
+					"mux_dclk1", dclk_s3c2443_p,
+					ARRAY_SIZE(dclk_s3c2443_p), 0,
+					s3c24xx_dclk->base, 17, 1, 0,
+					&s3c24xx_dclk->dclk_lock);
+	} else {
+		clk_table[MUX_DCLK0] = clk_register_mux(&pdev->dev,
+					"mux_dclk0", dclk_s3c2410_p,
+					ARRAY_SIZE(dclk_s3c2410_p), 0,
+					s3c24xx_dclk->base, 1, 1, 0,
+					&s3c24xx_dclk->dclk_lock);
+		clk_table[MUX_DCLK1] = clk_register_mux(&pdev->dev,
+					"mux_dclk1", dclk_s3c2410_p,
+					ARRAY_SIZE(dclk_s3c2410_p), 0,
+					s3c24xx_dclk->base, 17, 1, 0,
+					&s3c24xx_dclk->dclk_lock);
+	}
+
+	clk_table[DIV_DCLK0] = clk_register_divider(&pdev->dev, "div_dclk0",
+					"mux_dclk0", 0, s3c24xx_dclk->base,
+					4, 4, 0, &s3c24xx_dclk->dclk_lock);
+	clk_table[DIV_DCLK1] = clk_register_divider(&pdev->dev, "div_dclk1",
+					"mux_dclk1", 0, s3c24xx_dclk->base,
+					20, 4, 0, &s3c24xx_dclk->dclk_lock);
+
+	clk_table[GATE_DCLK0] = clk_register_gate(&pdev->dev, "gate_dclk0",
+					"div_dclk0", CLK_SET_RATE_PARENT,
+					s3c24xx_dclk->base, 0, 0,
+					&s3c24xx_dclk->dclk_lock);
+	clk_table[GATE_DCLK1] = clk_register_gate(&pdev->dev, "gate_dclk1",
+					"div_dclk1", CLK_SET_RATE_PARENT,
+					s3c24xx_dclk->base, 16, 0,
+					&s3c24xx_dclk->dclk_lock);
+
+	switch (current_soc) {
+	case S3C2410:
+		clkout0_parent_names = clkout0_s3c2410_p;
+		clkout0_num_parents = ARRAY_SIZE(clkout0_s3c2410_p);
+		clkout1_parent_names = clkout1_s3c2410_p;
+		clkout1_num_parents = ARRAY_SIZE(clkout1_s3c2410_p);
+		break;
+	case S3C2412:
+		clkout0_parent_names = clkout0_s3c2412_p;
+		clkout0_num_parents = ARRAY_SIZE(clkout0_s3c2412_p);
+		clkout1_parent_names = clkout1_s3c2412_p;
+		clkout1_num_parents = ARRAY_SIZE(clkout1_s3c2412_p);
+		break;
+	case S3C2440:
+		clkout0_parent_names = clkout0_s3c2440_p;
+		clkout0_num_parents = ARRAY_SIZE(clkout0_s3c2440_p);
+		clkout1_parent_names = clkout1_s3c2440_p;
+		clkout1_num_parents = ARRAY_SIZE(clkout1_s3c2440_p);
+		break;
+	case S3C2443:
+		clkout0_parent_names = clkout0_s3c2443_p;
+		clkout0_num_parents = ARRAY_SIZE(clkout0_s3c2443_p);
+		clkout1_parent_names = clkout1_s3c2443_p;
+		clkout1_num_parents = ARRAY_SIZE(clkout1_s3c2443_p);
+		break;
+	default:
+		dev_err(&pdev->dev, "unsupported soc %d\n", current_soc);
+		ret = -EINVAL;
+		goto err_clk_register;
+	}
+
+	clk_table[MUX_CLKOUT0] = s3c24xx_register_clkout(&pdev->dev,
+				"clkout0", clkout0_parent_names,
+				clkout0_num_parents, misccr, 4, 7);
+	clk_table[MUX_CLKOUT1] = s3c24xx_register_clkout(&pdev->dev, "clkout1",
+				clkout1_parent_names,
+				clkout1_num_parents, misccr, 8, 7);
+
+	for (i = 0; i < DCLK_MAX_CLKS; i++)
+		if (IS_ERR(clk_table[i])) {
+			dev_err(&pdev->dev, "clock %d failed to register\n", i);
+			ret = PTR_ERR(clk_table[i]);
+			goto err_clk_register;
+		}
+
+	ret = clk_register_clkdev(clk_table[MUX_DCLK0], "dclk0", NULL);
+	ret |= clk_register_clkdev(clk_table[MUX_DCLK1], "dclk1", NULL);
+	ret |= clk_register_clkdev(clk_table[MUX_CLKOUT0], "clkout0", NULL);
+	ret |= clk_register_clkdev(clk_table[MUX_CLKOUT1], "clkout1", NULL);
+	if (ret) {
+		dev_err(&pdev->dev, "failed to register aliases\n");
+		goto err_clk_register;
+	}
+
+	s3c24xx_dclk->dclk0_div_change_nb.notifier_call =
+						s3c24xx_dclk0_div_notify;
+	s3c24xx_dclk->dclk0_div_change_nb.next = NULL;
+
+	s3c24xx_dclk->dclk1_div_change_nb.notifier_call =
+						s3c24xx_dclk1_div_notify;
+	s3c24xx_dclk->dclk1_div_change_nb.next = NULL;
+
+	ret = clk_notifier_register(clk_table[DIV_DCLK0],
+				    &s3c24xx_dclk->dclk0_div_change_nb);
+	if (ret)
+		goto err_clk_register;
+
+	ret = clk_notifier_register(clk_table[DIV_DCLK1],
+				    &s3c24xx_dclk->dclk1_div_change_nb);
+	if (ret)
+		goto err_dclk_notify;
+
+	if (np) {
+		ret = of_clk_add_provider(np,
+			      of_clk_src_onecell_get, &s3c24xx_dclk->clk_data);
+		if (ret)
+			goto err_of_clk_provider;
+	}
+
+	return 0;
+
+err_of_clk_provider:
+	clk_notifier_unregister(clk_table[DIV_DCLK1],
+				&s3c24xx_dclk->dclk1_div_change_nb);
+err_dclk_notify:
+	clk_notifier_unregister(clk_table[DIV_DCLK0],
+				&s3c24xx_dclk->dclk0_div_change_nb);
+err_clk_register:
+	for (i = 0; i < DCLK_MAX_CLKS; i++)
+		if (clk_table[i] && !IS_ERR(clk_table[i]))
+			clk_unregister(clk_table[i]);
+
+	return ret;
+}
+
+static int s3c24xx_dclk_remove(struct platform_device *pdev)
+{
+	struct s3c24xx_dclk *s3c24xx_dclk = platform_get_drvdata(pdev);
+	struct clk **clk_table = s3c24xx_dclk->clk_data.clks;
+	int i;
+
+	of_clk_del_provider(pdev->dev.of_node);
+
+	clk_notifier_unregister(clk_table[DIV_DCLK1],
+				&s3c24xx_dclk->dclk1_div_change_nb);
+	clk_notifier_unregister(clk_table[DIV_DCLK0],
+				&s3c24xx_dclk->dclk0_div_change_nb);
+
+	for (i = 0; i < DCLK_MAX_CLKS; i++)
+		clk_unregister(clk_table[i]);
+
+	return 0;
+}
+
+static struct s3c24xx_dclk_drv_data s3c24xx_dclk_drv_data_array[] = {
+	[S3C2410] = { S3C2410 },
+	[S3C2412] = { S3C2412 },
+	[S3C2440] = { S3C2440 },
+	[S3C2443] = { S3C2443 },
+};
+
+static const struct of_device_id s3c24xx_dclk_dt_match[] = {
+	{
+		.compatible = "samsung,s3c2410-dclk",
+		.data = &s3c24xx_dclk_drv_data_array[S3C2410],
+	}, {
+		.compatible = "samsung,s3c2412-dclk",
+		.data = &s3c24xx_dclk_drv_data_array[S3C2412],
+	}, {
+		.compatible = "samsung,s3c2440-dclk",
+		.data = &s3c24xx_dclk_drv_data_array[S3C2440],
+	}, {
+		.compatible = "samsung,s3c2443-dclk",
+		.data = &s3c24xx_dclk_drv_data_array[S3C2443],
+	},
+	{ },
+};
+MODULE_DEVICE_TABLE(of, s3c24xx_dclk_dt_match);
+
+static struct platform_device_id s3c24xx_dclk_driver_ids[] = {
+	{
+		.name		= "s3c2410-dclk",
+		.driver_data	= S3C2410,
+	}, {
+		.name		= "s3c2412-dclk",
+		.driver_data	= S3C2412,
+	}, {
+		.name		= "s3c2440-dclk",
+		.driver_data	= S3C2440,
+	}, {
+		.name		= "s3c2443-dclk",
+		.driver_data	= S3C2443,
+	},
+	{ }
+};
+
+MODULE_DEVICE_TABLE(platform, s3c24xx_dclk_driver_ids);
+
+static struct platform_driver s3c24xx_dclk_driver = {
+	.driver = {
+		.name		= "s3c24xx-dclk",
+		.owner		= THIS_MODULE,
+		.pm		= &s3c24xx_dclk_pm_ops,
+		.of_match_table	= of_match_ptr(s3c24xx_dclk_dt_match),
+	},
+	.probe = s3c24xx_dclk_probe,
+	.remove = s3c24xx_dclk_remove,
+	.id_table = s3c24xx_dclk_driver_ids,
+};
+module_platform_driver(s3c24xx_dclk_driver);
+
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Heiko Stuebner <heiko@sntech.de>");
+MODULE_DESCRIPTION("Driver for the S3C24XX external clock outputs");
diff --git a/include/dt-bindings/clock/samsung,s3c2410-dclk.h b/include/dt-bindings/clock/samsung,s3c2410-dclk.h
new file mode 100644
index 0000000..7394d46
--- /dev/null
+++ b/include/dt-bindings/clock/samsung,s3c2410-dclk.h
@@ -0,0 +1,28 @@ 
+/*
+ * Copyright (c) 2013 Heiko Stuebner <heiko@sntech.de>
+ *
+ * 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.
+ *
+ * Device Tree binding constants clock controllers of Samsung S3C2410 and later.
+ */
+
+#ifndef _DT_BINDINGS_CLOCK_SAMSUNG_S3C2410_CLOCK_H
+#define _DT_BINDINGS_CLOCK_SAMSUNG_S3C2410_CLOCK_H
+
+#define MUX_DCLK0	0
+#define MUX_DCLK1	1
+
+#define DIV_DCLK0	2
+#define DIV_DCLK1	3
+
+#define GATE_DCLK0	4
+#define GATE_DCLK1	5
+
+#define MUX_CLKOUT0	6
+#define MUX_CLKOUT1	7
+
+#define DCLK_MAX_CLKS	(MUX_CLKOUT1 + 1)
+
+#endif