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Subject: Re: [PATCH v5 3/3] clk: meson: add sub MMC clock controller driver
To:     Jerome Brunet <jbrunet@baylibre.com>,
        Neil Armstrong <narmstrong@baylibre.com>
CC:     Yixun Lan <yixun.lan@amlogic.com>,
        Kevin Hilman <khilman@baylibre.com>,
        Carlo Caione <carlo@caione.org>,
        Michael Turquette <mturquette@baylibre.com>,
        Stephen Boyd <sboyd@kernel.org>, Rob Herring <robh@kernel.org>,
        Miquel Raynal <miquel.raynal@bootlin.com>,
        Boris Brezillon <boris.brezillon@bootlin.com>,
        Martin Blumenstingl <martin.blumenstingl@googlemail.com>,
        Liang Yang <liang.yang@amlogic.com>,
        Jian Hu <jian.hu@amlogic.com>,
        Qiufang Dai <qiufang.dai@amlogic.com>,
        Hanjie Lin <hanjie.lin@amlogic.com>,
        Victor Wan <victor.wan@amlogic.com>,
        <linux-clk@vger.kernel.org>, <linux-amlogic@lists.infradead.org>,
        <linux-arm-kernel@lists.infradead.org>,
        <linux-kernel@vger.kernel.org>
References: <1539839245-13793-1-git-send-email-jianxin.pan@amlogic.com>
 <1539839245-13793-4-git-send-email-jianxin.pan@amlogic.com>
 <a8d359208edfdc75cb5c6de378796f76e0572a0f.camel@baylibre.com>
From:   Jianxin Pan <jianxin.pan@amlogic.com>
Message-ID: <eda2faf2-cf06-902d-36ff-48ceafcb4a4b@amlogic.com>
Date:   Thu, 25 Oct 2018 19:48:41 +0800
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Hi Jerome,

On 2018/10/24 17:01, Jerome Brunet wrote:
> On Thu, 2018-10-18 at 13:07 +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.
>>
[...]
>> diff --git a/drivers/clk/meson/Kconfig b/drivers/clk/meson/Kconfig
>> index efaa70f..8b8ccbc 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 COMMON_CLK_AMLOGIC
> 
> COMMON_CLK_AMLOGIC is not something that is manually enabled
> You should select it, not depends on it. Have a look at how it is done for the
> other controller (like in v4.19)
OK. I will fix it.
> 
>> +	select MFD_SYSCON
>> +	select REGMAP
> 
> this is already selected by COMMON_CLK_AMLOGIC, please drop this.
OK.
> 
>> +	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 39ce566..31c16d5 100644
>> --- a/drivers/clk/meson/Makefile
>> +++ b/drivers/clk/meson/Makefile
>> @@ -9,4 +9,5 @@ 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/clk-regmap.c b/drivers/clk/meson/clk-regmap.c
>> index 305ee30..f96314d 100644
>> --- a/drivers/clk/meson/clk-regmap.c
>> +++ b/drivers/clk/meson/clk-regmap.c
>> @@ -113,8 +113,25 @@ static int clk_regmap_div_set_rate(struct clk_hw *hw, unsigned long rate,
>>  				  clk_div_mask(div->width) << div->shift, val);
>>  };
>>  
>> -/* Would prefer clk_regmap_div_ro_ops but clashes with qcom */
>> +static void clk_regmap_div_init(struct clk_hw *hw)
>> +{
>> +	struct clk_regmap *clk = to_clk_regmap(hw);
>> +	struct clk_regmap_div_data *div = clk_get_regmap_div_data(clk);
>> +	unsigned int val;
>> +	int ret;
>> +
>> +	ret = regmap_read(clk->map, div->offset, &val);
>> +	if (ret)
>> +		return;
>>  
>> +	val &= (clk_div_mask(div->width) << div->shift);
>> +	if (!val)
>> +		regmap_update_bits(clk->map, div->offset,
>> +				   clk_div_mask(div->width) << div->shift,
>> +				   clk_div_mask(div->width));
> 
> This is wrong for several reasons:
> * You should hard code the initial value in the driver.
> * If shift is not 0, I doubt this will give the expected result.
The value 0x00 of divider means nand clock off, then read/write nand register is forbidden.
Should we set the initial value in nand driver, or in sub emmc clk driver?  
> 
>> +}
> 
> Please drop this. 
> 
>> +
>> +/* Would prefer clk_regmap_div_ro_ops but clashes with qcom */
>>  const struct clk_ops clk_regmap_divider_ops = {
>>  	.recalc_rate = clk_regmap_div_recalc_rate,
>>  	.round_rate = clk_regmap_div_round_rate,
>> @@ -122,6 +139,14 @@ static int clk_regmap_div_set_rate(struct clk_hw *hw, unsigned long rate,
>>  };
>>  EXPORT_SYMBOL_GPL(clk_regmap_divider_ops);
>>  
>> +const struct clk_ops clk_regmap_divider_with_init_ops = {
>> +	.recalc_rate = clk_regmap_div_recalc_rate,
>> +	.round_rate = clk_regmap_div_round_rate,
>> +	.set_rate = clk_regmap_div_set_rate,
>> +	.init = clk_regmap_div_init,
>> +};
>> +EXPORT_SYMBOL_GPL(clk_regmap_divider_with_init_ops);
> 
> ... and this.
> 
>> +
>>  const struct clk_ops clk_regmap_divider_ro_ops = {
>>  	.recalc_rate = clk_regmap_div_recalc_rate,
>>  	.round_rate = clk_regmap_div_round_rate,
>> diff --git a/drivers/clk/meson/clk-regmap.h b/drivers/clk/meson/clk-regmap.h
>> index ed2d434..0ab7d37 100644
>> --- a/drivers/clk/meson/clk-regmap.h
>> +++ b/drivers/clk/meson/clk-regmap.h
>> @@ -109,5 +109,6 @@ struct clk_regmap_mux_data {
>>  
>>  extern const struct clk_ops clk_regmap_mux_ops;
>>  extern const struct clk_ops clk_regmap_mux_ro_ops;
>> +extern const struct clk_ops clk_regmap_divider_with_init_ops;
> 
> ... and this as well.
> 
> There is no reason to to init the divider to something other than what it is
> already when we register the clock controller.
> 
> If your consumer needs the clocks to be initialised, it should call
> clk_set_rate()
> 
>>  
>>  #endif /* __CLK_REGMAP_H */
>> diff --git a/drivers/clk/meson/mmc-clkc.c b/drivers/clk/meson/mmc-clkc.c
>> new file mode 100644
>> index 0000000..5555e3f
>> --- /dev/null
>> +++ b/drivers/clk/meson/mmc-clkc.c
>> @@ -0,0 +1,296 @@
>> +// 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>
>> + */
>> +
>> +#include <linux/clk.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 CLKID_MMC_MUX			0
>> +
>> +#define   SD_EMMC_CLOCK		0
>> +#define   CLK_DELAY_STEP_PS		200
>> +#define   CLK_PHASE_STEP		30
>> +#define   CLK_PHASE_POINT_NUM		(360 / CLK_PHASE_STEP)
>> +
>> +#define MUX_CLK_NUM_PARENTS		2
>> +#define MMC_MAX_CLKS			5
>> +
>> +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,
>> +	.flags		= CLK_DIVIDER_ROUND_CLOSEST,
>> +};
>> +
>> +static struct clk_regmap_div_data mmc_clkc_div_data = {
>> +	.offset		= SD_EMMC_CLOCK,
>> +	.shift		= 0,
>> +	.width		= 6,
>> +	.flags		= CLK_DIVIDER_ROUND_CLOSEST | 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,
>> +	},
>> +	.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_PTR((long)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 char *parent,
> 
> I would prefer if you passed the parent clk_hw pointer and call
> clk_hw_get_name() in here
OK. I will fix it. Thanks for your review.
> 
>> +				  unsigned long flags,
>> +				  const struct clk_ops *ops, void *data)
>> +{
>> +	struct clk_init_data init;
>> +	struct clk_regmap *clk;
>> +
>> +	init.ops = ops;
>> +	init.flags = flags;
>> +	init.parent_names = (const char* const []){ parent, };
>> +	init.num_parents = 1;
>> +
>> +	clk = mmc_clkc_register_clk(dev, map, &init, suffix, data);
>> +	if (IS_ERR(clk))
>> +		dev_err(dev, "Core %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 *mux, *div, *core, *rx, *tx;
> 
> You really don't need all these local variables ( I think I already pointed this
> out in past reviews ...)
> 
> You can keep one struct clk_regmap *clk and store the clk->hw in the onecell
> data right after registering the clock.
OK, I will remove them.
> 
> 
>> +
>> +	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;
>> +
>> +	mux = mmc_clkc_register_mux(dev, map);
>> +	if (IS_ERR(mux))
>> +		return PTR_ERR(mux);
>> +
>> +	div = mmc_clkc_register_clk_with_parent(dev, map, "div",
>> +						clk_hw_get_name(&mux->hw),
>> +						CLK_SET_RATE_PARENT,
>> +						&clk_regmap_divider_with_init_ops,
>> +						&mmc_clkc_div_data);
>> +	if (IS_ERR(div))
>> +		return PTR_ERR(div);
>> +
>> +	core = mmc_clkc_register_clk_with_parent(dev, map, "core",
>> +						 clk_hw_get_name(&div->hw),
>> +						 CLK_SET_RATE_PARENT,
>> +						 &meson_clk_phase_ops,
>> +						 &mmc_clkc_core_phase);
>> +	if (IS_ERR(core))
>> +		return PTR_ERR(core);
>> +
>> +	rx = mmc_clkc_register_clk_with_parent(dev, map, "rx",
>> +					       clk_hw_get_name(&core->hw),  0,
>> +					       &meson_clk_phase_delay_ops,
>> +					       &data->rx);
>> +	if (IS_ERR(rx))
>> +		return PTR_ERR(rx);
>> +
>> +	tx = mmc_clkc_register_clk_with_parent(dev, map, "tx",
>> +					       clk_hw_get_name(&core->hw),  0,
>> +					       &meson_clk_phase_delay_ops,
>> +					       &data->tx);
>> +	if (IS_ERR(tx))
>> +		return PTR_ERR(tx);
>> +
>> +	onecell_data->hws[CLKID_MMC_MUX]		= &mux->hw,
>> +	onecell_data->hws[CLKID_MMC_DIV]		= &div->hw,
>> +	onecell_data->hws[CLKID_MMC_PHASE_CORE]		= &core->hw,
>> +	onecell_data->hws[CLKID_MMC_PHASE_RX]		= &rx->hw,
>> +	onecell_data->hws[CLKID_MMC_PHASE_TX]		= &tx->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);
> 
> This can be compiled as module so please append the proper:
> MODULE_DESCRIPTION()
> MODULE_AUTHOR()
> MODULE_LICENSE()
OK. I will fix it in the next version.
> 
> .
>