linux-kernel - Re: [PATCH v2] media: ov8856: Add runtime PM callbacks

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Date:   Wed, 21 Sep 2022 11:20:12 +0300
From:   Sakari Ailus <sakari.ailus@....fi>
To:     Hidenori Kobayashi <hidenorik@...omium.org>
Cc:     Dongchun Zhu <dongchun.zhu@...iatek.com>,
        Mauro Carvalho Chehab <mchehab@...nel.org>,
        linux-media@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2] media: ov8856: Add runtime PM callbacks

Hi Hidenori,

On Wed, Sep 21, 2022 at 05:15:35PM +0900, Hidenori Kobayashi wrote:
> There were no runtime PM callbacks registered, leaving regulators being
> enabled while the device is suspended on DT systems. Add callbacks that
> call existing power controlling functions to turn them off/on.
> 
> To simplify the code with this addition, change the argument of the
> power controlling functions.
> 
> Signed-off-by: Hidenori Kobayashi <hidenorik@...omium.org>
> ---
> V1 -> V2: Change argument of power controlling functions
> ---
>  drivers/media/i2c/ov8856.c | 41 ++++++++++++++++++++++++++------------
>  1 file changed, 28 insertions(+), 13 deletions(-)
> 
> diff --git a/drivers/media/i2c/ov8856.c b/drivers/media/i2c/ov8856.c
> index a9728afc81d4..188699455fdf 100644
> --- a/drivers/media/i2c/ov8856.c
> +++ b/drivers/media/i2c/ov8856.c
> @@ -2110,17 +2110,18 @@ static int ov8856_set_stream(struct v4l2_subdev *sd, int enable)
>  	return ret;
>  }
>  
> -static int __ov8856_power_on(struct ov8856 *ov8856)
> +static int __ov8856_power_on(struct device *dev)
>  {
> -	struct i2c_client *client = v4l2_get_subdevdata(&ov8856->sd);
> +	struct v4l2_subdev *sd = dev_get_drvdata(dev);
> +	struct ov8856 *ov8856 = to_ov8856(sd);
>  	int ret;
>  
> -	if (is_acpi_node(dev_fwnode(&client->dev)))
> +	if (is_acpi_node(dev_fwnode(dev)))
>  		return 0;
>  
>  	ret = clk_prepare_enable(ov8856->xvclk);
>  	if (ret < 0) {
> -		dev_err(&client->dev, "failed to enable xvclk\n");
> +		dev_err(dev, "failed to enable xvclk\n");
>  		return ret;
>  	}
>  
> @@ -2132,7 +2133,7 @@ static int __ov8856_power_on(struct ov8856 *ov8856)
>  	ret = regulator_bulk_enable(ARRAY_SIZE(ov8856_supply_names),
>  				    ov8856->supplies);
>  	if (ret < 0) {
> -		dev_err(&client->dev, "failed to enable regulators\n");
> +		dev_err(dev, "failed to enable regulators\n");
>  		goto disable_clk;
>  	}
>  
> @@ -2148,11 +2149,12 @@ static int __ov8856_power_on(struct ov8856 *ov8856)
>  	return ret;
>  }
>  
> -static void __ov8856_power_off(struct ov8856 *ov8856)
> +static void __ov8856_power_off(struct device *dev)
>  {
> -	struct i2c_client *client = v4l2_get_subdevdata(&ov8856->sd);
> +	struct v4l2_subdev *sd = dev_get_drvdata(dev);
> +	struct ov8856 *ov8856 = to_ov8856(sd);
>  
> -	if (is_acpi_node(dev_fwnode(&client->dev)))
> +	if (is_acpi_node(dev_fwnode(dev)))
>  		return;
>  
>  	gpiod_set_value_cansleep(ov8856->reset_gpio, 1);
> @@ -2170,7 +2172,7 @@ static int __maybe_unused ov8856_suspend(struct device *dev)
>  	if (ov8856->streaming)
>  		ov8856_stop_streaming(ov8856);
>  
> -	__ov8856_power_off(ov8856);
> +	__ov8856_power_off(dev);
>  	mutex_unlock(&ov8856->mutex);
>  
>  	return 0;
> @@ -2184,7 +2186,7 @@ static int __maybe_unused ov8856_resume(struct device *dev)
>  
>  	mutex_lock(&ov8856->mutex);
>  
> -	__ov8856_power_on(ov8856);
> +	__ov8856_power_on(dev);
>  	if (ov8856->streaming) {
>  		ret = ov8856_start_streaming(ov8856);
>  		if (ret) {
> @@ -2200,6 +2202,18 @@ static int __maybe_unused ov8856_resume(struct device *dev)
>  	return 0;
>  }
>  
> +static int __maybe_unused ov8856_runtime_suspend(struct device *dev)
> +{
> +	__ov8856_power_off(dev);
> +
> +	return 0;
> +}
> +
> +static int __maybe_unused ov8856_runtime_resume(struct device *dev)
> +{
> +	return __ov8856_power_on(dev);
> +}

These two functions are redundant now, you can call __ov8856_power_on /
__ov8856_power_off directly. The return type of __ov8856_power_off needs to
be changed to int. You could also remove the underscores from the names at
the same time.

> +
>  static int ov8856_set_format(struct v4l2_subdev *sd,
>  			     struct v4l2_subdev_state *sd_state,
>  			     struct v4l2_subdev_format *fmt)
> @@ -2451,7 +2465,7 @@ static int ov8856_remove(struct i2c_client *client)
>  	pm_runtime_disable(&client->dev);
>  	mutex_destroy(&ov8856->mutex);
>  
> -	__ov8856_power_off(ov8856);
> +	__ov8856_power_off(&client->dev);
>  
>  	return 0;
>  }
> @@ -2477,7 +2491,7 @@ static int ov8856_probe(struct i2c_client *client)
>  
>  	full_power = acpi_dev_state_d0(&client->dev);
>  	if (full_power) {
> -		ret = __ov8856_power_on(ov8856);
> +		ret = __ov8856_power_on(&client->dev);
>  		if (ret) {
>  			dev_err(&client->dev, "failed to power on\n");
>  			return ret;
> @@ -2533,13 +2547,14 @@ static int ov8856_probe(struct i2c_client *client)
>  	mutex_destroy(&ov8856->mutex);
>  
>  probe_power_off:
> -	__ov8856_power_off(ov8856);
> +	__ov8856_power_off(&client->dev);
>  
>  	return ret;
>  }
>  
>  static const struct dev_pm_ops ov8856_pm_ops = {
>  	SET_SYSTEM_SLEEP_PM_OPS(ov8856_suspend, ov8856_resume)
> +	SET_RUNTIME_PM_OPS(ov8856_runtime_suspend, ov8856_runtime_resume, NULL)
>  };
>  
>  #ifdef CONFIG_ACPI

-- 
Kind regards,

Sakari Ailus