Date:   Thu, 12 Jul 2018 17:33:23 +0800
From:   Yixun Lan <yixun.lan@...ogic.com>
To:     Jerome Brunet <jbrunet@...libre.com>,
        Neil Armstrong <narmstrong@...libre.com>
CC:     <yixun.lan@...ogic.com>, Kevin Hilman <khilman@...libre.com>,
        Carlo Caione <carlo@...one.org>,
        Michael Turquette <mturquette@...libre.com>,
        Stephen Boyd <sboyd@...nel.org>, Rob Herring <robh@...nel.org>,
        Miquel Raynal <miquel.raynal@...tlin.com>,
        Boris Brezillon <boris.brezillon@...tlin.com>,
        Martin Blumenstingl <martin.blumenstingl@...glemail.com>,
        Liang Yang <liang.yang@...ogic.com>,
        Qiufang Dai <qiufang.dai@...ogic.com>,
        Jian Hu <jian.hu@...ogic.com>, <linux-clk@...r.kernel.org>,
        <linux-amlogic@...ts.infradead.org>,
        <linux-arm-kernel@...ts.infradead.org>,
        <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2 3/3] clk: meson: add sub MMC clock controller driver

Hi Jerome

thanks for the review

On 07/12/18 17:09, Jerome Brunet wrote:
> On Tue, 2018-07-10 at 16:36 +0000, Yixun Lan wrote:
>> 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/emmc-clkc.h header
>> can be used in the device tree sources.
>>
>> Signed-off-by: Yixun Lan <yixun.lan@...ogic.com>
>> ---
>>  drivers/clk/meson/Kconfig    |   9 +
>>  drivers/clk/meson/Makefile   |   1 +
>>  drivers/clk/meson/mmc-clkc.c | 419 +++++++++++++++++++++++++++++++++++
>>  3 files changed, 429 insertions(+)
>>  create mode 100644 drivers/clk/meson/mmc-clkc.c
>>
>> diff --git a/drivers/clk/meson/Kconfig b/drivers/clk/meson/Kconfig
>> index efaa70f682b4..edc18e65c89b 100644
>> --- a/drivers/clk/meson/Kconfig
>> +++ b/drivers/clk/meson/Kconfig
>> @@ -15,6 +15,15 @@ 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
>> +	select MFD_SYSCON
>> +	select REGMAP
>> +	help
>> +	  Support for the MMC sub clock controller on Amlogic Meson Platform,
>> +	  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 72ec8c40d848..4b3817f80ba1 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/mmc-clkc.c b/drivers/clk/meson/mmc-clkc.c
>> new file mode 100644
>> index 000000000000..43b7a376746d
>> --- /dev/null
>> +++ b/drivers/clk/meson/mmc-clkc.c
>> @@ -0,0 +1,419 @@
>> +// SPDX-License-Identifier: (GPL-2.0+ OR MIT)
>> +/*
>> + * Amlogic Meson MMC Sub Clock Controller Driver
> 
>  * Copyright (c) 2017 Baylibre SAS.
>  * Author: Jerome Brunet <jbrunet@...libre.com>
> 
> Considering that a fair share of the code below has been copied from the clock
> portion of the eMMC driver, which I wrote last year.
> 
Ok, fair enough, will fix in next version

>> + *
>> + * Copyright (c) 2018 Amlogic, inc.
>> + * Author: Yixun Lan <yixun.lan@...ogic.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,meson-mmc-clkc.h>
>> +
>> +#include "clkc.h"
>> +
>> +/* clock ID used by internal driver */
>> +#define CLKID_MMC_MUX				0
>> +#define CLKID_MMC_PHASE_CORE			2
>> +
>> +#define SD_EMMC_CLOCK		0
>> +#define   CLK_DIV_MASK GENMASK(5, 0)
>> +#define   CLK_SRC_MASK GENMASK(7, 6)
>> +#define   CLK_CORE_PHASE_MASK GENMASK(9, 8)
>> +#define   CLK_TX_PHASE_MASK GENMASK(11, 10)
>> +#define   CLK_RX_PHASE_MASK GENMASK(13, 12)
>> +#define   CLK_V2_TX_DELAY_MASK GENMASK(19, 16)
>> +#define   CLK_V2_RX_DELAY_MASK GENMASK(23, 20)
>> +#define   CLK_V2_ALWAYS_ON BIT(24)
>> +
>> +#define   CLK_V3_TX_DELAY_MASK GENMASK(21, 16)
>> +#define   CLK_V3_RX_DELAY_MASK GENMASK(27, 22)
>> +#define   CLK_V3_ALWAYS_ON BIT(28)
>> +
>> +#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
> 
> Some defines are aligned, some aren't. please be consistent about it.
> I personally prefer when things are aligned but it is just a preference.  
> 
sounds good to me, I can fix this in next version

>> +
>> +struct clk_regmap_phase_data {
> 
> Considering the recent addition of clk_phase in clk/meson, it is not the best
> name to choose.
> 
> clk_phase_delay_data ?
> 
ok

>> +	unsigned long			phase_mask;
>> +	unsigned long			delay_mask;
>> +	unsigned int			delay_step_ps;
>> +};
>> +
>> +struct mmc_clkc_data {
>> +	struct clk_regmap_phase_data	tx;
>> +	struct clk_regmap_phase_data	rx;
>> +};
> 
> 
> 
>> +
>> +struct mmc_clkc_info {
>> +	struct device			*dev;
> 
> I don't think you need keep dev here, considering this is the device data.
> 
>> +	struct regmap			*map;
>> +	struct mmc_clkc_data		*data;
>> +};
> 
> Overall, I don't think you need this structure
> 
ok, I could simplify this and drop this structure.

>> +
>> +static inline struct clk_regmap_phase_data *
>> +clk_get_regmap_phase_data(struct clk_regmap *clk)
> 
> Update name as well
> 
sure

>> +{
>> +	return (struct clk_regmap_phase_data *)clk->data;
>> +}
>> +
>> +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,
>> +};
> 
> Same comment on alignement. Some structure you've aligned, and some you haven't
> Consistency ...
> 
will fix

>> +
>> +static struct clk_regmap_phase_data mmc_clkc_core_phase = {
>> +	.phase_mask	= CLK_CORE_PHASE_MASK,
>> +};
>> +
>> +static const struct mmc_clkc_data mmc_clkc_gx_data = {
>> +	{
>> +		.phase_mask	= CLK_TX_PHASE_MASK,
>> +		.delay_mask	= CLK_V2_TX_DELAY_MASK,
>> +		.delay_step_ps	= CLK_DELAY_STEP_PS,
>> +	},
>> +	{
>> +		.phase_mask	= CLK_RX_PHASE_MASK,
>> +		.delay_mask	= CLK_V2_RX_DELAY_MASK,
>> +		.delay_step_ps	= CLK_DELAY_STEP_PS,
>> +	},
>> +};
>> +
>> +static const struct mmc_clkc_data mmc_clkc_axg_data = {
>> +	{
>> +		.phase_mask	= CLK_TX_PHASE_MASK,
>> +		.delay_mask	= CLK_V3_TX_DELAY_MASK,
>> +		.delay_step_ps	= CLK_DELAY_STEP_PS,
>> +	},
>> +	{
>> +		.phase_mask	= CLK_RX_PHASE_MASK,
>> +		.delay_mask	= CLK_V3_RX_DELAY_MASK,
>> +		.delay_step_ps	= CLK_DELAY_STEP_PS,
>> +	},
>> +};
>> +
>> +static const struct of_device_id mmc_clkc_match_table[] = {
>> +	{
>> +		.compatible = "amlogic,meson-gx-mmc-clkc",
>> +		.data = &mmc_clkc_gx_data
>> +	},
>> +	{
>> +		.compatible = "amlogic,meson-axg-mmc-clkc",
>> +		.data = &mmc_clkc_axg_data
>> +	},
>> +	{}
>> +};
>> +MODULE_DEVICE_TABLE(of, mmc_clkc_match_table);
>> +
>> +static struct clk_regmap *mmc_clkc_register_mux(struct mmc_clkc_info *clkc)
>> +{
>> +	const char *parent_names[MUX_CLK_NUM_PARENTS];
>> +	struct device *dev = clkc->dev;
>> +	struct clk_init_data init;
>> +	struct clk_regmap *mux;
>> +	struct clk *clk;
>> +	char *mux_name;
>> +	int i, ret;
>> +
>> +	mux = devm_kzalloc(dev, sizeof(*mux), GFP_KERNEL);
>> +	if (!mux)
>> +		return ERR_PTR(-ENOMEM);
>> +
>> +	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);
>> +	}
>> +
>> +	mux_name = kasprintf(GFP_KERNEL, "%s#mux", dev_name(dev));
>> +	if (!mux_name)
>> +		return ERR_PTR(-ENOMEM);
>> +
>> +	mux->map = clkc->map;
>> +	mux->data = &mmc_clkc_mux_data;
>> +
>> +	init.name = mux_name;
>> +	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->hw.init = &init;
>> +	ret = devm_clk_hw_register(dev, &mux->hw);
>> +	if (ret) {
>> +		dev_err(dev, "Mux clock registration failed\n");
>> +		mux = ERR_PTR(ret);
>> +	}
>> +
>> +	kfree(mux_name);
>> +	return mux;
>> +}
>> +
>> +static struct clk_regmap *mmc_clkc_register_div(struct mmc_clkc_info *clkc)
>> +{
>> +	const char *parent_names[MUX_CLK_NUM_PARENTS];
>> +	struct device *dev = clkc->dev;
>> +	struct clk_init_data init;
>> +	struct clk_regmap *div;
>> +	char *mux_name, *div_name;
>> +	int ret;
>> +
>> +	div = devm_kzalloc(dev, sizeof(*div), GFP_KERNEL);
>> +	if (!div)
>> +		return ERR_PTR(-ENOMEM);
>> +
>> +	mux_name = kasprintf(GFP_KERNEL, "%s#mux", dev_name(dev));
>> +	div_name = kasprintf(GFP_KERNEL, "%s#div", dev_name(dev));
>> +	if (!mux_name || !div_name) {
>> +		div = ERR_PTR(-ENOMEM);
>> +		goto err;
>> +	}
>> +
>> +	parent_names[0] = mux_name;
>> +	div->map = clkc->map;
>> +	div->data = &mmc_clkc_div_data;
>> +
>> +	init.name = div_name;
>> +	init.ops = &clk_regmap_divider_ops;
>> +	init.flags = CLK_SET_RATE_PARENT;
>> +	init.parent_names = parent_names;
>> +	init.num_parents = 1;
>> +
>> +	div->hw.init = &init;
>> +	ret = devm_clk_hw_register(dev, &div->hw);
>> +	if (ret) {
>> +		dev_err(dev, "Divider clock registration failed\n");
>> +		div = ERR_PTR(ret);
>> +	}
>> +
>> +err:
>> +	kfree(mux_name);
>> +	kfree(div_name);
>> +	return div;
>> +}
>> +
>> +static int clk_regmap_get_phase(struct clk_hw *hw)
>> +{
>> +	struct clk_regmap *clk = to_clk_regmap(hw);
>> +	struct clk_regmap_phase_data *ph = clk_get_regmap_phase_data(clk);
>> +	unsigned int phase_num = 1 <<  hweight_long(ph->phase_mask);
>> +	unsigned long period_ps, p, d;
>> +	int degrees;
>> +	u32 val;
>> +
>> +	regmap_read(clk->map, SD_EMMC_CLOCK, &val);
>> +	p = (val & ph->phase_mask) >> __ffs(ph->phase_mask);
>> +	degrees = p * 360 / phase_num;
>> +
>> +	if (ph->delay_mask) {
>> +		period_ps = DIV_ROUND_UP((unsigned long)NSEC_PER_SEC * 1000,
>> +					 clk_get_rate(hw->clk));
>> +		d = (val & ph->delay_mask) >> __ffs(ph->delay_mask);
>> +		degrees += d * ph->delay_step_ps * 360 / period_ps;
>> +		degrees %= 360;
>> +	}
>> +
>> +	return degrees;
>> +}
>> +
>> +static void clk_regmap_apply_phase_delay(struct clk_regmap *clk,
>> +					 unsigned int phase,
>> +					 unsigned int delay)
>> +{
>> +	struct clk_regmap_phase_data *ph = clk->data;
>> +	u32 val;
>> +
>> +	regmap_read(clk->map, SD_EMMC_CLOCK, &val);
>> +
>> +	val &= ~ph->phase_mask;
>> +	val |= phase << __ffs(ph->phase_mask);
>> +
>> +	if (ph->delay_mask) {
>> +		val &= ~ph->delay_mask;
>> +		val |= delay << __ffs(ph->delay_mask);
>> +	}
>> +
>> +	regmap_write(clk->map, SD_EMMC_CLOCK, val);
>> +}
>> +
>> +static int clk_regmap_set_phase(struct clk_hw *hw, int degrees)
>> +{
>> +	struct clk_regmap *clk = to_clk_regmap(hw);
>> +	struct clk_regmap_phase_data *ph = clk_get_regmap_phase_data(clk);
>> +	unsigned int phase_num = 1 <<  hweight_long(ph->phase_mask);
>> +	unsigned long period_ps, d = 0, r;
>> +	u64 p;
>> +
>> +	p = degrees % 360;
>> +
>> +	if (!ph->delay_mask) {
>> +		p = DIV_ROUND_CLOSEST_ULL(p, 360 / phase_num);
>> +	} else {
>> +		period_ps = DIV_ROUND_UP((unsigned long)NSEC_PER_SEC * 1000,
>> +					 clk_get_rate(hw->clk));
>> +
>> +		/* First compute the phase index (p), the remainder (r) is the
>> +		 * part we'll try to acheive using the delays (d).
>> +		 */
>> +		r = do_div(p, 360 / phase_num);
>> +		d = DIV_ROUND_CLOSEST(r * period_ps,
>> +				      360 * ph->delay_step_ps);
>> +		d = min(d, ph->delay_mask >> __ffs(ph->delay_mask));
>> +	}
>> +
>> +	clk_regmap_apply_phase_delay(clk, p, d);
>> +	return 0;
>> +}
>> +
>> +static const struct clk_ops clk_regmap_phase_ops = {
>> +	.get_phase = clk_regmap_get_phase,
>> +	.set_phase = clk_regmap_set_phase,
>> +};
>> +
>> +static struct clk_regmap *
>> +mmc_clkc_register_phase_clk(struct mmc_clkc_info *clkc,
>> +			    char *name, char *parent_name, unsigned long flags,
>> +			    struct clk_regmap_phase_data *phase_data)
>> +
>> +{
>> +	const char *parent_names[MUX_CLK_NUM_PARENTS];
>> +	struct device *dev = clkc->dev;
>> +	struct clk_init_data init;
>> +	struct clk_regmap *x;
> 
> x is not a very good name, 'clk' is just 2 more letters ...
> 
ok

>> +	char *clk_name, *core_name;
>> +	int ret;
>> +
>> +	/* create the mmc rx clock */
>> +	x = devm_kzalloc(dev, sizeof(*x), GFP_KERNEL);
>> +	if (!x)
>> +		return ERR_PTR(-ENOMEM);
>> +
>> +	clk_name = kasprintf(GFP_KERNEL, "%s#%s", dev_name(dev), name);
>> +	core_name = kasprintf(GFP_KERNEL, "%s#%s", dev_name(dev), parent_name);
>> +
>> +	if (!clk_name || !core_name) {
>> +		x = ERR_PTR(-ENOMEM);
>> +		goto err;
>> +	}
>> +	parent_names[0] = core_name;
>> +
>> +	init.name = clk_name;
>> +	init.ops = &clk_regmap_phase_ops;
>> +	init.flags = flags;
>> +	init.parent_names = parent_names;
>> +	init.num_parents = 1;
>> +
>> +	x->map = clkc->map;
>> +	x->data = phase_data;
>> +	x->hw.init = &init;
>> +
>> +	ret = devm_clk_hw_register(dev, &x->hw);
>> +	if (ret) {
>> +		dev_err(dev, "Core %s clock registration failed\n", name);
>> +		x = ERR_PTR(ret);
>> +	}
>> +err:
>> +	kfree(clk_name);
>> +	kfree(core_name);
>> +	return x;
>> +}
> 
> In all your mmc_clkc_register_xxx_() you should a pattern repeating itself. It
> is something I pointed out in the previous version of your patchset
> 
I probably mis-understand your suggestion.. which I gave a try to
construct a helper..

I need to rethink about this.

> 1. allocate a clk_regmap
> 2. allocate a clock name using dev name and a suffix.
> 3. register clk_hw
> 4. free clock name
> 5. return clk_regmap
> 
> You should be able to make an helper function out of this
> Prototype will probably look like this:
> 
> static struct clk_regmap *
> mmc_clkc_register_clk(struct device *dev, struct regmap *map,
> 		      struct clk_init_data *init, const char* suffix)
> 
ok, thanks for the suggestion

>> +
>> +static int mmc_clkc_probe(struct platform_device *pdev)
>> +{
>> +	struct device *dev = &pdev->dev;
>> +	struct mmc_clkc_info *clkc;
>> +	struct clk_regmap *mux, *div, *core, *rx, *tx;
>> +	struct clk_hw_onecell_data *onecell_data;
>> +
>> +	clkc = devm_kzalloc(dev, sizeof(*clkc), GFP_KERNEL);
>> +	if (!clkc)
>> +		return -ENOMEM;
>> +
>> +	clkc->data = (struct mmc_clkc_data *)of_device_get_match_data(dev);
>> +	if (!clkc->data)
>> +		return -EINVAL;
> 
> Prefer ENODEV for this
> 
ok

>> +
>> +	clkc->dev = dev;
>> +	clkc->map = syscon_node_to_regmap(dev->of_node);
>> +
>> +	if (IS_ERR(clkc->map)) {
>> +		dev_err(dev, "could not find mmc clock controller\n");
>> +		return PTR_ERR(clkc->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(clkc);
>> +	if (IS_ERR(mux))
>> +		return PTR_ERR(mux);
>> +
>> +	div = mmc_clkc_register_div(clkc);
>> +	if (IS_ERR(div))
>> +		return PTR_ERR(div);
>> +
>> +	core = mmc_clkc_register_phase_clk(clkc, "core", "div",
>> +					   CLK_SET_RATE_PARENT,
>> +					   &mmc_clkc_core_phase);
>> +	if (IS_ERR(core))
>> +		return PTR_ERR(core);
>> +
>> +	rx = mmc_clkc_register_phase_clk(clkc, "rx", "core", 0,
>> +					 &clkc->data->rx);
>> +	if (IS_ERR(rx))
>> +		return PTR_ERR(rx);
>> +
>> +	tx = mmc_clkc_register_phase_clk(clkc, "tx", "core", 0,
>> +					 &clkc->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);
> 
> .
> 

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