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

[Jerome Brunet <jbrunet@baylibre.com>]

On Tue, 2019-01-08 at 21:50 +0800, Jianxin Pan wrote:
> From: Yixun Lan <yixun.lan@amlogic.com>
> 
> The patch will add a MMC clock controller driver which used by MMC or NAND,
> It provide a mux and divider clock, and three phase clocks - core, tx, tx.
> 
> Two clocks are provided as the parent of MMC clock controller from
> upper layer clock controller - eg "amlogic,axg-clkc" in AXG platform.
> 
> To specify which clock the MMC or NAND driver may consume,
> the preprocessor macros in the dt-bindings/clock/amlogic,mmc-clkc.h header
> can be used in the device tree sources.
> 
> Signed-off-by: Yixun Lan <yixun.lan@amlogic.com>
> Signed-off-by: Jianxin Pan <jianxin.pan@amlogic.com>
> ---
>  drivers/clk/meson/Kconfig    |  10 ++
>  drivers/clk/meson/Makefile   |   1 +
>  drivers/clk/meson/mmc-clkc.c | 304
> +++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 315 insertions(+)
>  create mode 100644 drivers/clk/meson/mmc-clkc.c
> 
> diff --git a/drivers/clk/meson/Kconfig b/drivers/clk/meson/Kconfig
> index efaa70f..3555f9d 100644
> --- a/drivers/clk/meson/Kconfig
> +++ b/drivers/clk/meson/Kconfig
> @@ -15,6 +15,16 @@ config COMMON_CLK_MESON_AO
>  	select COMMON_CLK_REGMAP_MESON
>  	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
> +	help
> +	  Support for the MMC sub clock controller on Amlogic Meson Platform,
> +	  which include S905 (GXBB, GXL), A113D/X (AXG) devices.
> +	  Say Y if you want this clock enabled.
> +
>  config COMMON_CLK_REGMAP_MESON
>  	bool
>  	select REGMAP
> diff --git a/drivers/clk/meson/Makefile b/drivers/clk/meson/Makefile
> index d59620d..54416a2 100644
> --- a/drivers/clk/meson/Makefile
> +++ b/drivers/clk/meson/Makefile
> @@ -12,4 +12,5 @@ obj-$(CONFIG_COMMON_CLK_MESON8B) += meson8b.o
>  obj-$(CONFIG_COMMON_CLK_GXBB)	 += gxbb.o gxbb-aoclk.o gxbb-aoclk-
> 32k.o
>  obj-$(CONFIG_COMMON_CLK_AXG)	 += axg.o axg-aoclk.o
>  obj-$(CONFIG_COMMON_CLK_AXG_AUDIO)	+= axg-audio.o
> +obj-$(CONFIG_COMMON_CLK_MMC_MESON) 	+= mmc-clkc.o
>  obj-$(CONFIG_COMMON_CLK_REGMAP_MESON)	+= clk-regmap.o
> diff --git a/drivers/clk/meson/mmc-clkc.c b/drivers/clk/meson/mmc-clkc.c
> new file mode 100644
> index 0000000..2582a98
> --- /dev/null
> +++ b/drivers/clk/meson/mmc-clkc.c
> @@ -0,0 +1,304 @@
> +// SPDX-License-Identifier: (GPL-2.0+ OR MIT)
> +/*
> + * Amlogic Meson MMC Sub Clock Controller Driver
> + *
> + * Copyright (c) 2017 Baylibre SAS.
> + * Author: Jerome Brunet <jbrunet@baylibre.com>
> + *
> + * Copyright (c) 2018 Amlogic, inc.
> + * Author: Yixun Lan <yixun.lan@amlogic.com>
> + * Author: Jianxin Pan <jianxin.pan@amlogic.com>
> + */
> +
> +#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 "clkc.h"
> +
> +/* clock ID used by internal driver */
> +
> +#define SD_EMMC_CLOCK		0
> +#define CLK_DELAY_STEP_PS	200
> +#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 = CLK_DIVIDER_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,
> +	},
> +	.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,
> +	},
> +};
> +
> +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,

Please check this. The delay step is not 200ns on the 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,
> +	},
> +};
> +
> +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);
> +			return ERR_CAST(clk);
> +		}
> +
> +		parent_names[i] = __clk_get_name(clk);
> +	}
> +
> +	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*/
> +	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, sizeof(*onecell_data) +
> +				    sizeof(*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");