Re: [PATCH-v2 4/5] clk: 88pm800: Add clk provider driver for 88pm800 family of devices

[Krzysztof Kozlowski <k.kozlowski@samsung.com>]

On 25.08.2015 03:56, Vaibhav Hiremath wrote:
> 88PM800 family of devices supports buffered 32KHz clock output,
> for example,
> 
> 88PM800: CLK32k_1, CLK32k_2 and CLK32k_3
> 88PM860: CLK32K_1 and CLK32K_2
> 
> This patch adds new clk provider driver to support enable/disable
> of the 32KHz clock output from 88PM800 family of devices.
> 
> Signed-off-by: Vaibhav Hiremath <vaibhav.hiremath@linaro.org>
> ---
>  drivers/clk/Kconfig       |   8 ++
>  drivers/clk/Makefile      |   1 +
>  drivers/clk/clk-88pm800.c | 341 ++++++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 350 insertions(+)
>  create mode 100644 drivers/clk/clk-88pm800.c
> 
> diff --git a/drivers/clk/Kconfig b/drivers/clk/Kconfig
> index 42f7120..c34c14d 100644
> --- a/drivers/clk/Kconfig
> +++ b/drivers/clk/Kconfig
> @@ -167,6 +167,14 @@ config COMMON_CLK_CDCE706
>  	---help---
>  	  This driver supports TI CDCE706 programmable 3-PLL clock synthesizer.
>  
> +config COMMON_CLK_88PM800
> +	tristate "Clock driver for 88PM800 MFD"
> +	depends on MFD_88PM800
> +	---help---
> +	  This driver supports 88PM800 & 88PM860 crystal oscillator
> +	  clock. These multi-function devices have two (88PM860) or three
> +	  (88PM800) fixed-rate output, clocked at 32KHz each.
> +
>  source "drivers/clk/bcm/Kconfig"
>  source "drivers/clk/hisilicon/Kconfig"
>  source "drivers/clk/qcom/Kconfig"
> diff --git a/drivers/clk/Makefile b/drivers/clk/Makefile
> index c4cf075..5248cd3 100644
> --- a/drivers/clk/Makefile
> +++ b/drivers/clk/Makefile
> @@ -80,3 +80,4 @@ obj-$(CONFIG_X86)			+= x86/
>  obj-$(CONFIG_ARCH_ZX)			+= zte/
>  obj-$(CONFIG_ARCH_ZYNQ)			+= zynq/
>  obj-$(CONFIG_H8300)		+= h8300/
> +obj-$(CONFIG_COMMON_CLK_88PM800)	+= clk-88pm800.o
> diff --git a/drivers/clk/clk-88pm800.c b/drivers/clk/clk-88pm800.c
> new file mode 100644
> index 0000000..4c045e1
> --- /dev/null
> +++ b/drivers/clk/clk-88pm800.c
> @@ -0,0 +1,341 @@
> +/*
> + * clk-88pm800.c - Clock driver for 88PM800 family of devices
> + *
> + * This driver is created based on clk-s2mps11.c
> + *
> + * Copyright (C) 2015 Linaro Ltd.
> + *
> + * This program is free software; you can redistribute  it and/or modify it
> + * under  the terms of  the GNU General  Public License as published by the
> + * Free Software Foundation;  either version 2 of the  License, or (at your
> + * option) any later version.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + *
> + */
> +
> +#include <linux/module.h>
> +#include <linux/err.h>
> +#include <linux/of.h>
> +#include <linux/clkdev.h>
> +#include <linux/regmap.h>
> +#include <linux/clk-provider.h>
> +#include <linux/platform_device.h>
> +#include <linux/mfd/88pm80x.h>
> +
> +/* Number of clocks output from 88pm800 family of device */
> +enum {
> +	PM800_CLK32K_1 = 0,
> +	PM800_CLK32K_2,
> +	PM800_CLK32K_3,
> +	PM800_CLKS_NUM,
> +};
> +
> +struct pm800_clk {
> +	struct pm80x_chip *chip;
> +	struct device_node *clk_np;
> +	struct clk_hw hw;
> +	struct clk *clk;
> +	struct clk_lookup *lookup;
> +	u32 mask;
> +	u32 shift;
> +	unsigned int reg;
> +};
> +
> +static struct pm800_clk *to_pm800_clk(struct clk_hw *hw)
> +{
> +	return container_of(hw, struct pm800_clk, hw);
> +}
> +
> +static int pm800_clk_prepare(struct clk_hw *hw)
> +{
> +	struct pm800_clk *pm800 = to_pm800_clk(hw);
> +
> +	/* We always want to use XO clock */
> +	return regmap_update_bits(pm800->chip->regmap,
> +				 pm800->reg,
> +				 pm800->mask,
> +				 PM800_32K_OUTX_SEL_XO_32KHZ << pm800->shift);
> +}
> +
> +static void pm800_clk_unprepare(struct clk_hw *hw)
> +{
> +	struct pm800_clk *pm800 = to_pm800_clk(hw);
> +
> +	regmap_update_bits(pm800->chip->regmap, pm800->reg,
> +				pm800->mask, ~pm800->mask);
> +}
> +
> +static int pm800_clk_is_prepared(struct clk_hw *hw)
> +{
> +	int ret;
> +	u32 val;
> +	struct pm800_clk *pm800 = to_pm800_clk(hw);
> +
> +	ret = regmap_read(pm800->chip->regmap,
> +				pm800->reg, &val);
> +	if (ret < 0)
> +		return -EINVAL;
> +
> +	return (val & pm800->mask) >> pm800->shift;
> +}
> +
> +static unsigned long pm800_clk_recalc_rate(struct clk_hw *hw,
> +					     unsigned long parent_rate)
> +{
> +	return 32768;
> +}
> +
> +static const struct clk_ops pm800_clk_ops = {
> +	.prepare	= pm800_clk_prepare,
> +	.unprepare	= pm800_clk_unprepare,
> +	.is_prepared	= pm800_clk_is_prepared,
> +	.recalc_rate	= pm800_clk_recalc_rate,
> +};
> +
> +static struct clk_init_data pm800_clks_init[PM800_CLKS_NUM] = {
> +	[PM800_CLK32K_1] = {
> +		.name	= "pm800_clk32k_1",
> +		.ops	= &pm800_clk_ops,
> +		.flags	= CLK_IS_ROOT,
> +	},
> +	[PM800_CLK32K_2] = {
> +		.name	= "pm800_clk32k_2",
> +		.ops	= &pm800_clk_ops,
> +		.flags	= CLK_IS_ROOT,
> +	},
> +	[PM800_CLK32K_3] = {
> +		.name	= "pm800_clk32k_3",
> +		.ops	= &pm800_clk_ops,
> +		.flags	= CLK_IS_ROOT,
> +	},
> +};
> +
> +static struct clk_init_data pm860_clks_init[PM800_CLKS_NUM] = {
> +	[PM800_CLK32K_1] = {
> +		.name	= "pm800_clk32k_1",
> +		.ops	= &pm800_clk_ops,
> +		.flags	= CLK_IS_ROOT,
> +	},
> +	[PM800_CLK32K_2] = {
> +		.name	= "pm800_clk32k_2",
> +		.ops	= &pm800_clk_ops,
> +		.flags	= CLK_IS_ROOT,
> +	},
> +};
> +
> +static int pm800_init_clk(struct pm800_clk *pm800_clks)
> +{
> +	int ret;
> +
> +	/* Enable XO_LJ : Low jitter clock of 32KHz from XO */
> +	ret = regmap_update_bits(pm800_clks->chip->regmap, PM800_LOW_POWER2,
> +			PM800_LOW_POWER2_XO_LJ_EN, PM800_LOW_POWER2_XO_LJ_EN);
> +	if (ret)
> +		return ret;
> +
> +	/* Enable USE_XO : Use XO clock for all internal timing reference */
> +	ret = regmap_update_bits(pm800_clks->chip->regmap, PM800_RTC_CONTROL,
> +			PM800_RTC1_USE_XO, PM800_RTC1_USE_XO);
> +	if (ret)
> +		return ret;
> +
> +	/* OSC_FREERUN: Enable Osc free running mode by clearing the bit */
> +	ret = regmap_update_bits(pm800_clks->chip->regmap, PM800_OSC_CNTRL1,
> +			PM800_OSC_CNTRL1_OSC_FREERUN_EN, 0);
> +	if (ret)
> +		return ret;
> +
> +	return 0;
> +}
> +
> +static struct device_node *pm800_clk_parse_dt(struct platform_device *pdev,
> +		struct clk_init_data *clks_init)
> +{
> +	struct pm80x_chip *chip = dev_get_drvdata(pdev->dev.parent);
> +	struct device_node *clk_np;
> +	int i;
> +
> +	if (!chip->dev->of_node)
> +		return ERR_PTR(-EINVAL);
> +
> +	clk_np = of_get_child_by_name(chip->dev->of_node, "clocks");
> +	if (!clk_np) {
> +		dev_err(&pdev->dev, "could not find clock sub-node\n");
> +		return ERR_PTR(-EINVAL);
> +	}
> +
> +	for (i = 0; i < PM800_CLKS_NUM; i++) {
> +		if (!clks_init[i].name)
> +			continue; /* Skip clocks not present in some devices */
> +
> +		of_property_read_string_index(clk_np, "clock-output-names", i,
> +				&clks_init[i].name);
> +	}
> +
> +	return clk_np;
> +}
> +
> +static int pm800_clk_probe(struct platform_device *pdev)
> +{
> +	struct pm80x_chip *chip = dev_get_drvdata(pdev->dev.parent);
> +	struct pm800_clk *pm800_clks;
> +	struct clk_init_data *clks_init;
> +	static struct clk **clk_table;
> +	static struct clk_onecell_data *of_clk_data;
> +	int i, ret;
> +
> +	pm800_clks = devm_kcalloc(&pdev->dev, PM800_CLKS_NUM,
> +				sizeof(*pm800_clks), GFP_KERNEL);
> +	if (!pm800_clks)
> +		return -ENOMEM;
> +
> +	clk_table = devm_kcalloc(&pdev->dev, PM800_CLKS_NUM,
> +				sizeof(struct clk *), GFP_KERNEL);
> +	if (!clk_table)
> +		return -ENOMEM;
> +
> +	switch (platform_get_device_id(pdev)->driver_data) {
> +	case CHIP_PM800:
> +		clks_init = pm800_clks_init;
> +		break;
> +	case CHIP_PM860:
> +		clks_init = pm860_clks_init;
> +		break;
> +	default:
> +		dev_err(&pdev->dev, "Invalid device type\n");
> +		return -EINVAL;
> +	}
> +
> +	/* Store clocks of_node in first element of pm800_clks array */
> +	pm800_clks->clk_np = pm800_clk_parse_dt(pdev, clks_init);
> +	if (IS_ERR(pm800_clks->clk_np))
> +		return PTR_ERR(pm800_clks->clk_np);
> +
> +	of_clk_data = devm_kzalloc(&pdev->dev, sizeof(*of_clk_data), GFP_KERNEL);
> +	if (!of_clk_data) {
> +		ret = -ENOMEM;
> +		goto err_clk_np;
> +	}
> +
> +	for (i = 0; i < PM800_CLKS_NUM; i++) {
> +		if (!clks_init[i].name)
> +			continue; /* Skip clocks not present in some devices */
> +
> +		pm800_clks[i].chip = chip;
> +		pm800_clks[i].hw.init = &clks_init[i];
> +		/*
> +		 * As of now, mask and shift formula below works for both
> +		 * 88PM800 and it's family of devices,
> +		 *
> +		 *  PM800_RTC_MISC2:
> +		 *      1:0	= CK_32K_OUT1_SEL
> +		 *      3:2	= CK_32K_OUT2_SEL
> +		 *      5:4	= CK_32K_OUT3_SEL
> +		 */
> +		pm800_clks[i].shift = i * 2;
> +		pm800_clks[i].mask = PM800_32K_OUTX_SEL_MASK << pm800_clks[i].shift;
> +		pm800_clks[i].reg = PM800_RTC_MISC2;
> +
> +		pm800_clks[i].clk = devm_clk_register(&pdev->dev,
> +							&pm800_clks[i].hw);
> +		if (IS_ERR(pm800_clks[i].clk)) {
> +			dev_err(&pdev->dev, "Fail to register : %s\n",
> +						clks_init[i].name);
> +			ret = PTR_ERR(pm800_clks[i].clk);
> +			goto err;
> +		}
> +
> +		pm800_clks[i].lookup = clkdev_create(pm800_clks[i].clk,
> +					clks_init[i].name, NULL);
> +		if (!pm800_clks[i].lookup) {
> +			ret = -ENOMEM;
> +			goto err;
> +		}
> +
> +		clk_table[i] = pm800_clks[i].clk;
> +	}
> +
> +	of_clk_data->clks = clk_table;
> +	of_clk_data->clk_num = PM800_CLKS_NUM;
> +	ret = of_clk_add_provider(pm800_clks->clk_np, of_clk_src_onecell_get,
> +			of_clk_data);
> +	if (ret) {
> +		dev_err(&pdev->dev, "Fail to add OF clk provider : %d\n", ret);
> +		goto err;
> +	}
> +
> +	/* Common for all 32KHz clock output */
> +	ret = pm800_init_clk(&pm800_clks[0]);
> +	if (ret) {
> +		dev_err(&pdev->dev, "Failed to initialize clk : %d\n", ret);
> +		goto err;

You're missing here of_clk_del_provider().

> +	}
> +
> +	platform_set_drvdata(pdev, pm800_clks);
> +
> +	return 0;
> +
> +err:
> +	for (i = 0; i < PM800_CLKS_NUM; i++) {
> +		if (pm800_clks[i].lookup)
> +			clkdev_drop(pm800_clks[i].lookup);
> +	}
> +err_clk_np:
> +	/* Drop the reference obtained in pm800_clk_parse_dt */
> +	of_node_put(pm800_clks[0].clk_np);
> +
> +	return ret;
> +}
> +
> +static int pm800_clk_remove(struct platform_device *pdev)
> +{
> +	struct pm800_clk *pm800_clks = platform_get_drvdata(pdev);
> +	int i;
> +
> +	of_clk_del_provider(pm800_clks[0].clk_np);
> +	/* Drop the reference obtained in pm800_clk_parse_dt */
> +	of_node_put(pm800_clks[0].clk_np);
> +
> +	for (i = 0; i < PM800_CLKS_NUM; i++) {
> +		if (pm800_clks[i].lookup)
> +			clkdev_drop(pm800_clks[i].lookup);
> +	}
> +
> +	return 0;
> +}
> +
> +static const struct platform_device_id pm800_clk_id[] = {
> +	{ "88pm800-clk", CHIP_PM800},
> +	{ "88pm860-clk", CHIP_PM860},
> +	{ },
> +};
> +MODULE_DEVICE_TABLE(platform, pm800_clk_id);
> +
> +static struct platform_driver pm800_clk_driver = {
> +	.driver = {
> +		.name  = "88pm80x-clk",
> +	},
> +	.probe = pm800_clk_probe,
> +	.remove = pm800_clk_remove,
> +	.id_table = pm800_clk_id,
> +};
> +
> +static int __init pm800_clk_init(void)
> +{
> +	return platform_driver_register(&pm800_clk_driver);
> +}
> +subsys_initcall(pm800_clk_init);

Does it have to be subsys_initcall instead of regular
module_platform_driver? Strict ordering of modules should be avoided. Do
you require it?

Rest looks fine (actually Stephen pointed some issue during previous
review so I had easier job).

Best regards,
Krzysztof