Re: [PATCH v9 4/4] clk: meson: add sub MMC clock controller driver

[Liang Yang <liang.yang@amlogic.com>]

Hi Stephen,

On 2022/1/14 5:35, Stephen Boyd wrote:
> [ EXTERNAL EMAIL ]
> 
> Quoting Liang Yang (2022-01-13 03:57:45)
>> diff --git a/drivers/clk/meson/Kconfig b/drivers/clk/meson/Kconfig
>> index bb0f59eea366..3de6f3b24461 100644
>> --- a/drivers/clk/meson/Kconfig
>> +++ b/drivers/clk/meson/Kconfig
>> @@ -39,6 +39,20 @@ config COMMON_CLK_MESON_AO_CLKC
>>          select COMMON_CLK_MESON_REGMAP
>>          select RESET_CONTROLLER
>>   
>> +config COMMON_CLK_MMC_MESON
>> +       tristate "Meson MMC Sub Clock Controller Driver"
>> +       depends on ARCH_MESON || COMPILE_TEST
>> +       select MFD_SYSCON
>> +       select COMMON_CLK_AMLOGIC
>> +       select COMMON_CLK_MESON_PHASE
>> +       select COMMON_CLK_MESON_PHASE_DELAY
>> +       select COMMON_CLK_MESON_SCLK_DIV
>> +       help
>> +         Support for the MMC sub clock controller on
>> +         Amlogic Meson Platform, which includes S905 (GXBB, GXL),
>> +         A113D/X (AXG) devices . Say Y if you want this
> 
> s/devices /devices/
ok, i will fix it
> 
>> +         clock enabled.
>> +
>>   config COMMON_CLK_MESON_EE_CLKC
>>          tristate
>>          select COMMON_CLK_MESON_REGMAP
>> diff --git a/drivers/clk/meson/mmc-clkc.c b/drivers/clk/meson/mmc-clkc.c
>> new file mode 100644
>> index 000000000000..f53977f61390
>> --- /dev/null
>> +++ b/drivers/clk/meson/mmc-clkc.c
>> @@ -0,0 +1,300 @@
>> +// SPDX-License-Identifier: (GPL-2.0+ OR MIT)
>> +/*
>> + * Copyright (c) 2019 Amlogic, Inc. All rights reserved.
>> + */
>> +
>> +#include <linux/clk.h>
>> +#include <linux/clk-provider.h>
>> +#include <linux/module.h>
>> +#include <linux/regmap.h>
>> +#include <linux/slab.h>
>> +#include <linux/of_device.h>
>> +#include <linux/mfd/syscon.h>
>> +#include <linux/platform_device.h>
>> +#include <dt-bindings/clock/amlogic,mmc-clkc.h>
>> +
>> +#include "sclk-div.h"
>> +#include "clk-phase-delay.h"
>> +#include "clk-regmap.h"
>> +#include "clk-phase.h"
>> +
>> +/* clock ID used by internal driver */
>> +
>> +#define SD_EMMC_CLOCK          0
>> +#define CLK_DELAY_STEP_PS_GX   200
>> +#define CLK_DELAY_STEP_PS_AXG  78
>> +#define MUX_CLK_NUM_PARENTS    2
>> +#define MMC_MAX_CLKS           4
>> +
>> +struct mmc_clkc_data {
>> +       struct meson_clk_phase_delay_data tx;
>> +       struct meson_clk_phase_delay_data rx;
>> +};
>> +
>> +static struct clk_regmap_mux_data mmc_clkc_mux_data = {
>> +       .offset = SD_EMMC_CLOCK,
>> +       .mask   = 0x3,
>> +       .shift  = 6,
>> +};
>> +
>> +static const struct meson_sclk_div_data mmc_clkc_div_data = {
>> +       .div = {
>> +               .reg_off = SD_EMMC_CLOCK,
>> +               .width   = 6,
>> +       },
>> +       .flags = MESON_SCLK_ONE_BASED,
>> +};
>> +
>> +static struct meson_clk_phase_data mmc_clkc_core_phase = {
>> +       .ph = {
>> +               .reg_off = SD_EMMC_CLOCK,
>> +               .shift   = 8,
>> +               .width   = 2,
>> +       }
>> +};
>> +
>> +static const struct mmc_clkc_data mmc_clkc_gx_data = {
>> +       .tx = {
>> +               .phase = {
>> +                       .reg_off = SD_EMMC_CLOCK,
>> +                       .shift   = 10,
>> +                       .width   = 2,
>> +               },
>> +               .delay = {
>> +                       .reg_off = SD_EMMC_CLOCK,
>> +                       .shift   = 16,
>> +                       .width   = 4,
>> +               },
>> +               .delay_step_ps = CLK_DELAY_STEP_PS_GX,
>> +       },
>> +       .rx = {
>> +               .phase = {
>> +                       .reg_off = SD_EMMC_CLOCK,
>> +                       .shift   = 12,
>> +                       .width   = 2,
>> +               },
>> +               .delay = {
>> +                       .reg_off = SD_EMMC_CLOCK,
>> +                       .shift   = 20,
>> +                       .width   = 4,
>> +               },
>> +               .delay_step_ps   = CLK_DELAY_STEP_PS_GX,
>> +       },
>> +};
>> +
>> +static const struct mmc_clkc_data mmc_clkc_axg_data = {
>> +       .tx = {
>> +               .phase = {
>> +                       .reg_off = SD_EMMC_CLOCK,
>> +                       .shift   = 10,
>> +                       .width   = 2,
>> +               },
>> +               .delay = {
>> +                       .reg_off = SD_EMMC_CLOCK,
>> +                       .shift   = 16,
>> +                       .width   = 6,
>> +               },
>> +               .delay_step_ps   = CLK_DELAY_STEP_PS_AXG,
>> +       },
>> +       .rx = {
>> +               .phase = {
>> +                       .reg_off = SD_EMMC_CLOCK,
>> +                       .shift   = 12,
>> +                       .width   = 2,
>> +               },
>> +               .delay = {
>> +                       .reg_off = SD_EMMC_CLOCK,
>> +                       .shift   = 22,
>> +                       .width   = 6,
>> +               },
>> +               .delay_step_ps   = CLK_DELAY_STEP_PS_AXG,
>> +       },
>> +};
>> +
>> +static const struct of_device_id mmc_clkc_match_table[] = {
>> +       {
>> +               .compatible     = "amlogic,gx-mmc-clkc",
>> +               .data           = &mmc_clkc_gx_data
>> +       },
>> +       {
>> +               .compatible     = "amlogic,axg-mmc-clkc",
>> +               .data           = &mmc_clkc_axg_data
>> +       },
>> +       {}
>> +};
>> +MODULE_DEVICE_TABLE(of, mmc_clkc_match_table);
>> +
>> +static struct clk_regmap *
>> +mmc_clkc_register_clk(struct device *dev, struct regmap *map,
>> +                     struct clk_init_data *init,
>> +                     const char *suffix, void *data)
>> +{
>> +       struct clk_regmap *clk;
>> +       char *name;
>> +       int ret;
>> +
>> +       clk = devm_kzalloc(dev, sizeof(*clk), GFP_KERNEL);
>> +       if (!clk)
>> +               return ERR_PTR(-ENOMEM);
>> +
>> +       name = kasprintf(GFP_KERNEL, "%s#%s", dev_name(dev), suffix);
>> +       if (!name)
>> +               return ERR_PTR(-ENOMEM);
>> +
>> +       init->name = name;
>> +       clk->map = map;
>> +       clk->data = data;
>> +       clk->hw.init = init;
>> +       ret = devm_clk_hw_register(dev, &clk->hw);
>> +       if (ret)
>> +               clk = ERR_PTR(ret);
>> +
>> +       kfree(name);
>> +       return clk;
>> +}
>> +
>> +static struct clk_regmap *mmc_clkc_register_mux(struct device *dev,
>> +                                               struct regmap *map)
>> +{
>> +       const char *parent_names[MUX_CLK_NUM_PARENTS];
>> +       struct clk_init_data init;
>> +       struct clk_regmap *mux;
>> +       struct clk *clk;
>> +       int i;
>> +
>> +       for (i = 0; i < MUX_CLK_NUM_PARENTS; i++) {
>> +               char name[8];
>> +
>> +               snprintf(name, sizeof(name), "clkin%d", i);
>> +               clk = devm_clk_get(dev, name);
>> +               if (IS_ERR(clk)) {
>> +                       if (clk != ERR_PTR(-EPROBE_DEFER))
>> +                               dev_err(dev, "Missing clock %s\n", name);
> 
> Use dev_err_probe()?
ok
> 
>> +                       return ERR_CAST(clk);
>> +               }
>> +
>> +               parent_names[i] = __clk_get_name(clk);
> 
> Why can't we use clk_parent_data?

ok, i will try clk_parent_data.

> 
>> +       }
>> +
>> +       init.ops = &clk_regmap_mux_ops;
>> +       init.flags = CLK_SET_RATE_PARENT;
>> +       init.parent_names = parent_names;
>> +       init.num_parents = MUX_CLK_NUM_PARENTS;
>> +
>> +       mux = mmc_clkc_register_clk(dev, map, &init, "mux", &mmc_clkc_mux_data);
>> +       if (IS_ERR(mux))
>> +               dev_err(dev, "Mux clock registration failed\n");
>> +
>> +       return mux;
>> +}
>> +
>> +static struct clk_regmap *
>> +mmc_clkc_register_clk_with_parent(struct device *dev, struct regmap *map,
>> +                                 char *suffix, const struct clk_hw *hw,
>> +                                 unsigned long flags,
>> +                                 const struct clk_ops *ops, void *data)
>> +{
>> +       struct clk_init_data init;
>> +       struct clk_regmap *clk;
>> +       const char *parent_name = clk_hw_get_name(hw);
>> +
>> +       init.ops = ops;
>> +       init.flags = flags;
>> +       init.parent_names = &parent_name;
>> +       init.num_parents = 1;
>> +
>> +       clk = mmc_clkc_register_clk(dev, map, &init, suffix, data);
>> +       if (IS_ERR(clk))
>> +               dev_err(dev, "%s clock registration failed\n", suffix);
>> +
>> +       return clk;
>> +}
>> +
>> +static int mmc_clkc_probe(struct platform_device *pdev)
>> +{
>> +       struct clk_hw_onecell_data *onecell_data;
>> +       struct device *dev = &pdev->dev;
>> +       struct mmc_clkc_data *data;
>> +       struct regmap *map;
>> +       struct clk_regmap *clk, *core;
>> +       struct meson_sclk_div_data *div_data;
>> +
>> +       /*cast to drop the const in match->data*/
> 
> Space after *, also why do we need to cast away const? The user of this
> pointer passes it all the way down to mmc_clkc_register_clk() which
> could take the data as const void pointer and decide to cast away const
> there.

if use 'const' here, it will report a warning:
drivers/clk/meson/mmc-clkc.c:224:7: error: assignment discards ‘const’ 
qualifier from pointer targe
t type [-Werror=discarded-qualifiers] 

   data = (const struct mmc_clkc_data *)of_device_get_match_data(dev);

> 
>> +       data = (struct mmc_clkc_data *)of_device_get_match_data(dev);
>> +       if (!data)
>> +               return -ENODEV;
>> +
>> +       map = syscon_node_to_regmap(dev->of_node);
>> +       if (IS_ERR(map)) {
>> +               dev_err(dev, "could not find mmc clock controller\n");
>> +               return PTR_ERR(map);
>> +       }
>> +
>> +       onecell_data = devm_kzalloc(dev,
>> +                                   struct_size(onecell_data, hws,
>> +                                               MMC_MAX_CLKS),
>> +                                   GFP_KERNEL);
>> +       if (!onecell_data)
>> +               return -ENOMEM;
>> +
>> +       clk = mmc_clkc_register_mux(dev, map);
>> +       if (IS_ERR(clk))
>> +               return PTR_ERR(clk);
>> +
>> +       div_data = devm_kzalloc(dev, sizeof(*div_data), GFP_KERNEL);
>> +       if (!div_data)
>> +               return -ENOMEM;
>> +
>> +       memcpy(div_data, &mmc_clkc_div_data, sizeof(*div_data));
>> +       clk = mmc_clkc_register_clk_with_parent(dev, map, "div",
>> +                                               &clk->hw,
>> +                                               CLK_SET_RATE_PARENT,
>> +                                               &meson_sclk_div_ops,
>> +                                               div_data);
>> +       if (IS_ERR(clk))
>> +               return PTR_ERR(clk);
>> +
>> +       onecell_data->hws[CLKID_MMC_DIV] = &clk->hw;
>> +       core = mmc_clkc_register_clk_with_parent(dev, map, "core",
>> +                                                &clk->hw,
>> +                                                CLK_SET_RATE_PARENT,
>> +                                                &meson_clk_phase_ops,
>> +                                                &mmc_clkc_core_phase);
>> +       if (IS_ERR(core))
>> +               return PTR_ERR(core);
>> +
>> +       onecell_data->hws[CLKID_MMC_PHASE_CORE] = &core->hw;
>> +       clk = mmc_clkc_register_clk_with_parent(dev, map, "rx",
>> +                                               &core->hw,  0,
>> +                                               &meson_clk_phase_delay_ops,
>> +                                               &data->rx);
>> +       if (IS_ERR(clk))
>> +               return PTR_ERR(clk);
>> +
>> +       onecell_data->hws[CLKID_MMC_PHASE_RX] = &clk->hw;
>> +       clk = mmc_clkc_register_clk_with_parent(dev, map, "tx",
>> +                                               &core->hw,  0,
>> +                                               &meson_clk_phase_delay_ops,
>> +                                               &data->tx);
>> +       if (IS_ERR(clk))
>> +               return PTR_ERR(clk);
>> +
>> +       onecell_data->hws[CLKID_MMC_PHASE_TX] = &clk->hw;
>> +       onecell_data->num = MMC_MAX_CLKS;
>> +       return devm_of_clk_add_hw_provider(dev, of_clk_hw_onecell_get,
>> +                                          onecell_data);
>> +}
>> +
>> +static struct platform_driver mmc_clkc_driver = {
>> +       .probe          = mmc_clkc_probe,
>> +       .driver         = {
>> +               .name   = "meson-mmc-clkc",
>> +               .of_match_table = of_match_ptr(mmc_clkc_match_table),
>> +       },
>> +};
>> +
>> +module_platform_driver(mmc_clkc_driver);
>> +
>> +MODULE_DESCRIPTION("Amlogic AXG MMC clock driver");
>> +MODULE_AUTHOR("Jianxin Pan <jianxin.pan@amlogic.com>");
>> +MODULE_LICENSE("GPL v2");
> 
> .