Re: [PATCH 2/2] gpio: rcar: Fine-grained Runtime PM support

[Laurent Pinchart <laurent.pinchart@ideasonboard.com>]

Hi Niklas,

Thank you for the patch.

On Thursday 08 Dec 2016 18:32:28 Niklas Söderlund wrote:
> From: Geert Uytterhoeven <geert+renesas@glider.be>
> 
> Currently gpio modules are runtime-resumed at probe time. This means the
> gpio module will be active all the time (except during system suspend,
> if not configured as a wake-up source).
> 
> While an R-Car Gen2 gpio module retains pins configured for output at
> the requested level while put in standby mode, gpio register cannot be
> accessed while suspended.  Unfortunately pm_runtime_get_sync() cannot be
> called from all contexts where gpio register access is needed. Hence
> move the Runtime PM handling from probe/remove time to gpio request/free
> time, which is probably the best we can do.
> 
> On r8a7791/koelsch, gpio modules 0, 1, 3, and 4 are now suspended during
> normal use (gpio2 is used for LEDs and regulators, gpio5 for keys, gpio6
> for SD-Card CD & WP, gpio7 for keys and regulators).
> 
> Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
> [Niklas: s/gpio_to_priv(chip)/gpiochip_get_data(chip)/]

Just curious, what's the rationale for this ?

> Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>

Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

> ---
>  drivers/gpio/gpio-rcar.c | 20 ++++++++++++++++----
>  1 file changed, 16 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/gpio/gpio-rcar.c b/drivers/gpio/gpio-rcar.c
> index 3b77c10..31ad288 100644
> --- a/drivers/gpio/gpio-rcar.c
> +++ b/drivers/gpio/gpio-rcar.c
> @@ -242,11 +242,24 @@ static void
> gpio_rcar_config_general_input_output_mode(struct gpio_chip *chip,
> 
>  static int gpio_rcar_request(struct gpio_chip *chip, unsigned offset)
>  {
> -	return pinctrl_request_gpio(chip->base + offset);
> +	struct gpio_rcar_priv *p = gpiochip_get_data(chip);
> +	int error;
> +
> +	error = pm_runtime_get_sync(&p->pdev->dev);
> +	if (error < 0)
> +		return error;
> +
> +	error = pinctrl_request_gpio(chip->base + offset);
> +	if (error)
> +		pm_runtime_put(&p->pdev->dev);
> +
> +	return error;
>  }
> 
>  static void gpio_rcar_free(struct gpio_chip *chip, unsigned offset)
>  {
> +	struct gpio_rcar_priv *p = gpiochip_get_data(chip);
> +
>  	pinctrl_free_gpio(chip->base + offset);
> 
>  	/*
> @@ -254,6 +267,8 @@ static void gpio_rcar_free(struct gpio_chip *chip,
> unsigned offset) * drive the GPIO pin as an output.
>  	 */
>  	gpio_rcar_config_general_input_output_mode(chip, offset, false);
> +
> +	pm_runtime_put(&p->pdev->dev);
>  }
> 
>  static int gpio_rcar_direction_input(struct gpio_chip *chip, unsigned
> offset) @@ -426,7 +441,6 @@ static int gpio_rcar_probe(struct
> platform_device *pdev) }
> 
>  	pm_runtime_enable(dev);
> -	pm_runtime_get_sync(dev);
> 
>  	io = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>  	irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
> @@ -495,7 +509,6 @@ static int gpio_rcar_probe(struct platform_device *pdev)
> err1:
>  	gpiochip_remove(gpio_chip);
>  err0:
> -	pm_runtime_put(dev);
>  	pm_runtime_disable(dev);
>  	return ret;
>  }
> @@ -506,7 +519,6 @@ static int gpio_rcar_remove(struct platform_device
> *pdev)
> 
>  	gpiochip_remove(&p->gpio_chip);
> 
> -	pm_runtime_put(&pdev->dev);
>  	pm_runtime_disable(&pdev->dev);
>  	return 0;
>  }

-- 
Regards,

Laurent Pinchart