Re: [PATCH v4 10/11] ARM: EXYNOS: Add platform driver support for Exynos PMU.

[Tomasz Figa <t.figa@samsung.com>]

Hi Pankaj,

[dropping Young-Gun Jang <yg1004.jang@samsung.com>, as my mailer denies
to send to this address]

Please see my comments inline. I have skipped comments for changed
related to regmap, as according to our previous discussion they will be
dropped in next version.

On 10.05.2014 08:56, Pankaj Dubey wrote:
> This patch modifies Exynos Power Management Unit (PMU) initialization
> implementation in following way:
> 
> - Added platform_device support by registering static platform device.
> - Added platform struct exynos_pmu_data to hold platform specific data.
> - For each SoC's PMU support now we can add platform data and statically
>   bind PMU configuration and SoC specific initialization function.
> - Probe function will scan DT and based on matching PMU compatibility
>   string initialize pmu_context which will be platform_data for driver.
> - Obtain PMU regmap handle using "syscon_regmap_lookup_by_phandle" so
>   that we can reduce dependency over machine header files.
> - Separate each SoC's PMU initialization function and make it as part of
>   platform data.
> - It also removes uses of soc_is_exynosXYZ() thus making PMU implementation
>   independent of "plat/cpu.h".
> 
> Signed-off-by: Pankaj Dubey <pankaj.dubey@samsung.com>
> Signed-off-by: Young-Gun Jang <yg1004.jang@samsung.com>
> ---
>  arch/arm/mach-exynos/pmu.c |  266 ++++++++++++++++++++++++++++++++++----------
>  1 file changed, 210 insertions(+), 56 deletions(-)
> 
> diff --git a/arch/arm/mach-exynos/pmu.c b/arch/arm/mach-exynos/pmu.c
> index 67116a5..6a7fa8e 100644
> --- a/arch/arm/mach-exynos/pmu.c
> +++ b/arch/arm/mach-exynos/pmu.c
> @@ -1,5 +1,5 @@
>  /*
> - * Copyright (c) 2011-2012 Samsung Electronics Co., Ltd.
> + * Copyright (c) 2011-2014 Samsung Electronics Co., Ltd.
>   *		http://www.samsung.com/
>   *
>   * EXYNOS - CPU PMU(Power Management Unit) support
> @@ -9,20 +9,33 @@
>   * published by the Free Software Foundation.
>   */
>  
> -#include <linux/io.h>
> -#include <linux/kernel.h>
> +#include <linux/module.h>
>  #include <linux/regmap.h>
> -
> -#include <plat/cpu.h>
> +#include <linux/of.h>
> +#include <linux/platform_device.h>
> +#include <linux/slab.h>
> +#include <linux/mfd/syscon.h>
>  
>  #include "common.h"
>  #include "regs-pmu.h"
>  
> -static const struct exynos_pmu_conf *exynos_pmu_config;
> -static struct regmap *pmu_regmap;
> +struct exynos_pmu_data {
> +	const struct exynos_pmu_conf *pmu_config;
> +	const struct exynos_pmu_conf *pmu_config_extra;
> +	void (*pmu_init)(void);
> +	void (*powerdown_conf)(enum sys_powerdown);
> +};
> +
> +struct exynos_pmu_context {
> +	struct device *dev;
> +	struct exynos_pmu_data *pmu_data;
> +	struct regmap	*pmu_regmap;
> +};
> +
> +static struct exynos_pmu_context	*pmu_context;
>  
>  static const struct exynos_pmu_conf exynos4210_pmu_config[] = {
> -	/* { .reg = address, .val = { AFTR, LPA, SLEEP } */
> +	/* { .offset = address, .val = { AFTR, LPA, SLEEP } */

AFAICT those have changed already in patch 08/11.

>  	{ S5P_ARM_CORE0_LOWPWR,			{ 0x0, 0x0, 0x2 } },
>  	{ S5P_DIS_IRQ_CORE0,			{ 0x0, 0x0, 0x0 } },
>  	{ S5P_DIS_IRQ_CENTRAL0,			{ 0x0, 0x0, 0x0 } },
> @@ -216,7 +229,7 @@ static const struct exynos_pmu_conf exynos4412_pmu_config[] = {
>  };
>  
>  static const struct exynos_pmu_conf exynos5250_pmu_config[] = {
> -	/* { .reg = address, .val = { AFTR, LPA, SLEEP } */
> +	/* { .offset = address, .val = { AFTR, LPA, SLEEP } */

Ditto.

>  	{ EXYNOS5_ARM_CORE0_SYS_PWR_REG,		{ 0x0, 0x0, 0x2} },
>  	{ EXYNOS5_DIS_IRQ_ARM_CORE0_LOCAL_SYS_PWR_REG,	{ 0x0, 0x0, 0x0} },
>  	{ EXYNOS5_DIS_IRQ_ARM_CORE0_CENTRAL_SYS_PWR_REG,	{ 0x0, 0x0, 0x0} },
> @@ -339,7 +352,7 @@ static unsigned int const exynos5_list_diable_wfi_wfe[] = {
>  	EXYNOS5_ISP_ARM_OPTION,
>  };
>  
> -static void exynos5_init_pmu(void)
> +void exynos5_powerdown_conf(enum sys_powerdown mode)

static

>  {
>  	unsigned int i;
>  	unsigned int tmp;
> @@ -348,81 +361,222 @@ static void exynos5_init_pmu(void)
>  	 * Enable both SC_FEEDBACK and SC_COUNTER
>  	 */
>  	for (i = 0 ; i < ARRAY_SIZE(exynos5_list_both_cnt_feed) ; i++) {
> -		regmap_read(pmu_regmap, exynos5_list_both_cnt_feed[i], &tmp);
> +		regmap_read(pmu_context->pmu_regmap,
> +				exynos5_list_both_cnt_feed[i], &tmp);
>  		tmp |= (EXYNOS5_USE_SC_FEEDBACK |
>  			EXYNOS5_USE_SC_COUNTER);
> -		regmap_write(pmu_regmap, exynos5_list_both_cnt_feed[i], tmp);
> +		regmap_write(pmu_context->pmu_regmap,
> +				exynos5_list_both_cnt_feed[i], tmp);
>  	}
>  
>  	/*
>  	 * SKIP_DEACTIVATE_ACEACP_IN_PWDN_BITFIELD Enable
>  	 */
> -	regmap_read(pmu_regmap, EXYNOS5_ARM_COMMON_OPTION, &tmp);
> +	regmap_read(pmu_context->pmu_regmap, EXYNOS5_ARM_COMMON_OPTION, &tmp);
>  	tmp |= EXYNOS5_SKIP_DEACTIVATE_ACEACP_IN_PWDN;
> -	regmap_write(pmu_regmap, EXYNOS5_ARM_COMMON_OPTION, tmp);
> +	regmap_write(pmu_context->pmu_regmap, EXYNOS5_ARM_COMMON_OPTION, tmp);
>  
>  	/*
>  	 * Disable WFI/WFE on XXX_OPTION
>  	 */
>  	for (i = 0 ; i < ARRAY_SIZE(exynos5_list_diable_wfi_wfe) ; i++) {
> -		tmp = regmap_read(pmu_regmap, exynos5_list_diable_wfi_wfe[i],
> -				&tmp);
> +		tmp = regmap_read(pmu_context->pmu_regmap,
> +				exynos5_list_diable_wfi_wfe[i], &tmp);
>  		tmp &= ~(EXYNOS5_OPTION_USE_STANDBYWFE |
>  			 EXYNOS5_OPTION_USE_STANDBYWFI);
> -		regmap_write(pmu_regmap, exynos5_list_diable_wfi_wfe[i], tmp);
> +		regmap_write(pmu_context->pmu_regmap,
> +				exynos5_list_diable_wfi_wfe[i], tmp);
>  	}
>  }
>  
>  void exynos_sys_powerdown_conf(enum sys_powerdown mode)
>  {
>  	unsigned int i;
> +	struct exynos_pmu_data *pmu_data = pmu_context->pmu_data;
> +
> +	if (pmu_data->powerdown_conf)
> +		pmu_data->powerdown_conf(mode);
> +
> +	if (pmu_data->pmu_config) {
> +		for (i = 0; (pmu_data->pmu_config[i].offset != PMU_TABLE_END) ; i++)
> +			regmap_write(pmu_context->pmu_regmap,
> +					pmu_data->pmu_config[i].offset,
> +					pmu_data->pmu_config[i].val[mode]);
> +	}
> +
> +	if (pmu_data->pmu_config_extra) {
> +		for (i = 0; pmu_data->pmu_config_extra[i].offset != PMU_TABLE_END; i++)
> +			regmap_write(pmu_context->pmu_regmap,
> +					pmu_data->pmu_config_extra[i].offset,
> +					pmu_data->pmu_config_extra[i].val[mode]);
> +	}
> +}
> +
> +static void exynos5250_pmu_init(void)
> +{
> +	unsigned int tmp;
> +	struct regmap *pmu_regmap = pmu_context->pmu_regmap;
> +	/*
> +	 * When SYS_WDTRESET is set, watchdog timer reset request
> +	 * is ignored by power management unit.
> +	 */
> +	regmap_read(pmu_regmap, EXYNOS5_AUTO_WDTRESET_DISABLE, &tmp);
> +	tmp &= ~EXYNOS5_SYS_WDTRESET;
> +	regmap_write(pmu_regmap, EXYNOS5_AUTO_WDTRESET_DISABLE, tmp);
> +
> +	regmap_read(pmu_regmap, EXYNOS5_MASK_WDTRESET_REQUEST, &tmp);
> +	tmp &= ~EXYNOS5_SYS_WDTRESET;
> +	regmap_write(pmu_regmap, EXYNOS5_MASK_WDTRESET_REQUEST, tmp);
> +}
> +
> +static struct exynos_pmu_data exynos4210_pmu_data = {
> +	.pmu_config	= exynos4210_pmu_config,
> +};
> +
> +static struct exynos_pmu_data exynos4x12_pmu_data = {

Should be probably called exynos4212_pmu_data.

> +	.pmu_config	= exynos4x12_pmu_config,
> +};
> +
> +static struct exynos_pmu_data exynos4412_pmu_data = {
> +	.pmu_config		= exynos4x12_pmu_config,
> +	.pmu_config_extra	= exynos4412_pmu_config,
> +};
> +
> +static struct exynos_pmu_data exynos5250_pmu_data = {
> +	.pmu_config	= exynos5250_pmu_config,
> +	.pmu_init	= exynos5250_pmu_init,
> +	.powerdown_conf	= exynos5_powerdown_conf,
> +};
> +
> +/*
> + * PMU platform driver and devicetree bindings.
> + */
> +static struct of_device_id exynos_pmu_of_device_ids[] = {
> +	{
> +		.compatible = "samsung,exynos4210-pmu",
> +		.data = (void *)&exynos4210_pmu_data,
> +	},
> +	{
> +		.compatible = "samsung,exynos4212-pmu",
> +		.data = (void *)&exynos4x12_pmu_data,
> +	},
> +	{
> +		.compatible = "samsung,exynos4412-pmu",
> +		.data = (void *)&exynos4412_pmu_data,
> +	},
> +	{
> +		.compatible = "samsung,exynos5250-pmu",
> +		.data = (void *)&exynos5250_pmu_data,
> +	},
> +	{},
> +};
> +
> +static int exynos_pmu_probe(struct platform_device *pdev)
> +{
> +	struct device_node *np;
> +	const struct of_device_id *match;
> +	struct device *dev = &pdev->dev;
>  
> -	if (soc_is_exynos5250())
> -		exynos5_init_pmu();
> +	pmu_context = devm_kzalloc(&pdev->dev,
> +			sizeof(struct exynos_pmu_context),
> +			GFP_KERNEL);
> +	if (pmu_context == NULL) {
> +		dev_err(dev, "Cannot allocate memory.\n");
> +		return -ENOMEM;
> +	}
> +
> +	np = of_find_matching_node_and_match(NULL,
> +			exynos_pmu_of_device_ids, &match);
> +	if (!np) {
> +		pr_warn("%s, failed to find PMU node\n", __func__);
> +		return -ENODEV;
> +	}
>  
> -	for (i = 0; (exynos_pmu_config[i].offset != PMU_TABLE_END) ; i++)
> -		regmap_write(pmu_regmap, exynos_pmu_config[i].offset,
> -				exynos_pmu_config[i].val[mode]);
> +	pmu_context->pmu_data = (struct exynos_pmu_data *) match->data;
> +	pmu_context->pmu_regmap = syscon_regmap_lookup_by_phandle(np, NULL);
>  
> -	if (soc_is_exynos4412()) {
> -		for (i = 0; exynos4412_pmu_config[i].offset != PMU_TABLE_END; i++)
> -			regmap_write(pmu_regmap, exynos4412_pmu_config[i].offset,
> -					exynos4412_pmu_config[i].val[mode]);
> +	if (IS_ERR(pmu_context->pmu_regmap)) {
> +		pr_err("failed to find exynos_pmu_regmap\n");
> +		return PTR_ERR(pmu_context->pmu_regmap);
>  	}
> +
> +	if (pmu_context->pmu_data->pmu_init)
> +		pmu_context->pmu_data->pmu_init();
> +
> +	pmu_context->dev = dev;
> +
> +	platform_set_drvdata(pdev, pmu_context);
> +
> +	pr_info("Exynos PMU Driver probe done!!!\n");
> +	return 0;
> +}
> +
> +static int exynos_pmu_suspend(struct device *dev)
> +{
> +	/* ToDo: */
> +	return 0;
> +}
> +
> +static int exynos_pmu_resume(struct device *dev)
> +{
> +	/* ToDo: */
> +	return 0;
>  }

No need to add those if unused.

>  
> -static int __init exynos_pmu_init(void)
> +static const struct dev_pm_ops exynos_pmu_pm = {
> +	.suspend = exynos_pmu_suspend,
> +	.resume = exynos_pmu_resume,
> +};

You can drop this structure too.

> +
> +static int exynos_pmu_remove(struct platform_device *pdev)
> +{
> +	/* nothing to do here */
> +	return 0;
> +}

This function as well.

> +
> +static struct platform_device *exynos_pmu_pdev;
> +
> +static struct platform_driver exynos_pmu_driver = {
> +	.driver  = {
> +		.name   = "exynos-pmu",
> +		.owner	= THIS_MODULE,
> +		.pm	= &exynos_pmu_pm,
> +	},
> +	.probe = exynos_pmu_probe,
> +	.remove = exynos_pmu_remove,
> +};
> +
> +static int __init exynos_pmu_of_init(void)
>  {
> -	unsigned int value;
> -
> -	exynos_pmu_config = exynos4210_pmu_config;
> -	pmu_regmap = get_exynos_pmuregmap();
> -
> -	if (soc_is_exynos4210()) {
> -		exynos_pmu_config = exynos4210_pmu_config;
> -		pr_info("EXYNOS4210 PMU Initialize\n");
> -	} else if (soc_is_exynos4212() || soc_is_exynos4412()) {
> -		exynos_pmu_config = exynos4x12_pmu_config;
> -		pr_info("EXYNOS4x12 PMU Initialize\n");
> -	} else if (soc_is_exynos5250()) {
> -		/*
> -		 * When SYS_WDTRESET is set, watchdog timer reset request
> -		 * is ignored by power management unit.
> -		 */
> -		regmap_read(pmu_regmap, EXYNOS5_AUTO_WDTRESET_DISABLE, &value);
> -		value &= ~EXYNOS5_SYS_WDTRESET;
> -		regmap_write(pmu_regmap, EXYNOS5_AUTO_WDTRESET_DISABLE, value);
> -
> -		regmap_read(pmu_regmap, EXYNOS5_MASK_WDTRESET_REQUEST, &value);
> -		value &= ~EXYNOS5_SYS_WDTRESET;
> -		regmap_write(pmu_regmap, EXYNOS5_MASK_WDTRESET_REQUEST, value);
> -
> -		exynos_pmu_config = exynos5250_pmu_config;
> -		pr_info("EXYNOS5250 PMU Initialize\n");
> -	} else {
> -		pr_info("EXYNOS: PMU not supported\n");
> +	int ret;
> +
> +	ret = platform_driver_register(&exynos_pmu_driver);
> +	if (ret < 0)
> +		goto out;
> +
> +	exynos_pmu_pdev = platform_device_register_simple("exynos-pmu", -1,
> +			NULL, 0);

Hmm, I don't see the point of making this a platform driver only to
register respective platform device few lines below. If you take into
account the patch for syscon I posted as a reply to patch 06/11, you
will be able to make this a normal platform driver that binds to DT node
directly and then register a syscon in probe function above.

> +
> +	if (IS_ERR(exynos_pmu_pdev)) {
> +		ret = PTR_ERR(exynos_pmu_pdev);
> +		goto out1;
>  	}
>  
>  	return 0;
> +out1:
> +	platform_driver_unregister(&exynos_pmu_driver);
> +out:
> +	return ret;
>  }
> -arch_initcall(exynos_pmu_init);
> +arch_initcall(exynos_pmu_of_init);

Is there a need to change the name?

> +
> +static void __exit exynos_pmu_exit(void)
> +{
> +	platform_device_unregister(exynos_pmu_pdev);
> +	platform_driver_unregister(&exynos_pmu_driver);
> +}
> +module_exit(exynos_pmu_exit);

No need for module_exit() in case of such low level code. It will be
always built-in.

> +
> +MODULE_AUTHOR("Pankaj Dubey <pankaj.dubey@samsung.com");
> +MODULE_LICENSE("GPL v2");
> +MODULE_DESCRIPTION("EXYNOS Power Management Unit Driver");
> 

This driver will never be a module, so I don't think there is any need
for those.

--
Best regards,
Tomasz