linux-kernel - Re: [PATCH 1/2] pinctrl: pimux: Add support to save and restore HW register

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Message-ID: <36a272b2-1377-aaae-db37-cb40b618274a@kapsi.fi>
Date:   Tue, 31 Aug 2021 11:13:12 +0300
From:   Mikko Perttunen <cyndis@...si.fi>
To:     Prathamesh Shete <pshete@...dia.com>, linus.walleij@...aro.org,
        thierry.reding@...il.com, jonathanh@...dia.com,
        ldewangan@...dia.com, linux-gpio@...r.kernel.org,
        linux-tegra@...r.kernel.org, linux-kernel@...r.kernel.org
Cc:     smangipudi@...dia.com
Subject: Re: [PATCH 1/2] pinctrl: pimux: Add support to save and restore HW
 register

On 8/31/21 8:28 AM, Prathamesh Shete wrote:
> From: Laxman Dewangan <ldewangan@...dia.com>
> 
> Add support to save and restore the pincontrol HW register
> for GPIO mode configurations. This helps in changing the
> pin configure only during suspend and restore in resume.

Aren't we already saving all registers during suspend and restoring 
during resume?

> 
> Signed-off-by: Laxman Dewangan <ldewangan@...dia.com>
> Signed-off-by: pshete <pshete@...dia.com>

Needs full name. Also, there is a typo in the commit title, and it is 
quite vague (what HW register?)

Cheers,
Mikko

> ---
>   drivers/pinctrl/pinmux.c       | 24 ++++++++++++++++++++++++
>   drivers/pinctrl/pinmux.h       | 18 ++++++++++++++++++
>   include/linux/pinctrl/pinmux.h |  9 +++++++++
>   3 files changed, 51 insertions(+)
> 
> diff --git a/drivers/pinctrl/pinmux.c b/drivers/pinctrl/pinmux.c
> index 6cdbd9ccf2f0..66fc0ca22623 100644
> --- a/drivers/pinctrl/pinmux.c
> +++ b/drivers/pinctrl/pinmux.c
> @@ -317,6 +317,30 @@ int pinmux_gpio_direction(struct pinctrl_dev *pctldev,
>   	return ret;
>   }
>   
> +int pinmux_gpio_save_config(struct pinctrl_dev *pctldev,
> +			    struct pinctrl_gpio_range *range,
> +			    unsigned pin)
> +{
> +	const struct pinmux_ops *ops = pctldev->desc->pmxops;
> +
> +	if (ops->gpio_save_config)
> +		return ops->gpio_save_config(pctldev, range, pin);
> +
> +	return 0;
> +}
> +
> +int pinmux_gpio_restore_config(struct pinctrl_dev *pctldev,
> +			       struct pinctrl_gpio_range *range,
> +			       unsigned pin)
> +{
> +	const struct pinmux_ops *ops = pctldev->desc->pmxops;
> +
> +	if (ops->gpio_restore_config)
> +		return ops->gpio_restore_config(pctldev, range, pin);
> +
> +	return 0;
> +}
> +
>   static int pinmux_func_name_to_selector(struct pinctrl_dev *pctldev,
>   					const char *function)
>   {
> diff --git a/drivers/pinctrl/pinmux.h b/drivers/pinctrl/pinmux.h
> index 78c3a31be882..425c31a0115b 100644
> --- a/drivers/pinctrl/pinmux.h
> +++ b/drivers/pinctrl/pinmux.h
> @@ -31,6 +31,12 @@ int pinmux_map_to_setting(const struct pinctrl_map *map,
>   void pinmux_free_setting(const struct pinctrl_setting *setting);
>   int pinmux_enable_setting(const struct pinctrl_setting *setting);
>   void pinmux_disable_setting(const struct pinctrl_setting *setting);
> +int pinmux_gpio_save_config(struct pinctrl_dev *pctldev,
> +			    struct pinctrl_gpio_range *range,
> +			    unsigned pin);
> +int pinmux_gpio_restore_config(struct pinctrl_dev *pctldev,
> +			       struct pinctrl_gpio_range *range,
> +			       unsigned pin);
>   
>   #else
>   
> @@ -89,6 +95,18 @@ static inline void pinmux_disable_setting(const struct pinctrl_setting *setting)
>   {
>   }
>   
> +int pinmux_gpio_save_config(struct pinctrl_dev *pctldev,
> +			    struct pinctrl_gpio_range *range,
> +			    unsigned pin)
> +{
> +	return 0;
> +}
> +int pinmux_gpio_restore_config(struct pinctrl_dev *pctldev,
> +			       struct pinctrl_gpio_range *range,
> +			       unsigned pin)
> +{
> +	return 0;
> +}
>   #endif
>   
>   #if defined(CONFIG_PINMUX) && defined(CONFIG_DEBUG_FS)
> diff --git a/include/linux/pinctrl/pinmux.h b/include/linux/pinctrl/pinmux.h
> index 9a647fa5c8f1..cca87586d8c1 100644
> --- a/include/linux/pinctrl/pinmux.h
> +++ b/include/linux/pinctrl/pinmux.h
> @@ -53,6 +53,8 @@ struct pinctrl_dev;
>    *	depending on whether the GPIO is configured as input or output,
>    *	a direction selector function may be implemented as a backing
>    *	to the GPIO controllers that need pin muxing.
> + * @gpio_save_config: Save the GPIo configurations.
> + * @gpio_restore_config: Restore GPIO configurations.
>    * @strict: do not allow simultaneous use of the same pin for GPIO and another
>    *	function. Check both gpio_owner and mux_owner strictly before approving
>    *	the pin request.
> @@ -79,6 +81,13 @@ struct pinmux_ops {
>   				   struct pinctrl_gpio_range *range,
>   				   unsigned offset,
>   				   bool input);
> +	int (*gpio_save_config) (struct pinctrl_dev *pctldev,
> +				 struct pinctrl_gpio_range *range,
> +				 unsigned offset);
> +	int (*gpio_restore_config) (struct pinctrl_dev *pctldev,
> +				    struct pinctrl_gpio_range *range,
> +				    unsigned offset);
> +
>   	bool strict;
>   };
>   
>