Re: [PATCH v3 07/46] media: sun6i-csi: Use runtime pm for clocks and reset

[Jernej Škrabec]

Dne petek, 11. marec 2022 ob 15:34:53 CET je Paul Kocialkowski napisal(a):
> Wrap the clock and reset preparation into runtime pm functions
> for better organization of the code. Also fix the clock and
> reset enable order to first deassert reset, as recommended in
> Allwinner litterature.
> 
> Make the driver depend on PM while at it since runtime pm is
> mandatory for the driver to work.
> 
> Signed-off-by: Paul Kocialkowski <paul.kocialkowski@xxxxxxxxxxx>
> ---
>  .../media/platform/sunxi/sun6i-csi/Kconfig    |  2 +-
>  .../platform/sunxi/sun6i-csi/sun6i_csi.c      | 94 ++++++++++++++-----
>  2 files changed, 70 insertions(+), 26 deletions(-)
> 
> diff --git a/drivers/media/platform/sunxi/sun6i-csi/Kconfig b/drivers/media/
platform/sunxi/sun6i-csi/Kconfig
> index 586e3fb3a80d..fd03e48f0c8a 100644
> --- a/drivers/media/platform/sunxi/sun6i-csi/Kconfig
> +++ b/drivers/media/platform/sunxi/sun6i-csi/Kconfig
> @@ -1,7 +1,7 @@
>  # SPDX-License-Identifier: GPL-2.0-only
>  config VIDEO_SUN6I_CSI
>  	tristate "Allwinner V3s Camera Sensor Interface driver"
> -	depends on VIDEO_V4L2 && COMMON_CLK  && HAS_DMA
> +	depends on PM && VIDEO_V4L2 && COMMON_CLK  && HAS_DMA
>  	depends on ARCH_SUNXI || COMPILE_TEST
>  	select MEDIA_CONTROLLER
>  	select VIDEO_V4L2_SUBDEV_API
> diff --git a/drivers/media/platform/sunxi/sun6i-csi/sun6i_csi.c b/drivers/
media/platform/sunxi/sun6i-csi/sun6i_csi.c
> index 4a0d08e0ac25..7f045a9551a7 100644
> --- a/drivers/media/platform/sunxi/sun6i-csi/sun6i_csi.c
> +++ b/drivers/media/platform/sunxi/sun6i-csi/sun6i_csi.c
> @@ -152,40 +152,18 @@ int sun6i_csi_set_power(struct sun6i_csi_device 
*csi_dev, bool enable)
>  
>  	if (!enable) {
>  		regmap_update_bits(regmap, CSI_EN_REG, CSI_EN_CSI_EN, 
0);
> +		pm_runtime_put(dev);
>  
> -		clk_disable_unprepare(csi_dev->clk_ram);
> -		clk_disable_unprepare(csi_dev->clk_mod);
> -		reset_control_assert(csi_dev->reset);
>  		return 0;
>  	}
>  
> -	ret = clk_prepare_enable(csi_dev->clk_mod);
> -	if (ret) {
> -		dev_err(csi_dev->dev, "Enable csi clk err %d\n", ret);
> +	ret = pm_runtime_resume_and_get(dev);
> +	if (ret < 0)
>  		return ret;
> -	}
> -
> -	ret = clk_prepare_enable(csi_dev->clk_ram);
> -	if (ret) {
> -		dev_err(csi_dev->dev, "Enable clk_dram_csi clk err 
%d\n", ret);
> -		goto clk_mod_disable;
> -	}
> -
> -	ret = reset_control_deassert(csi_dev->reset);
> -	if (ret) {
> -		dev_err(csi_dev->dev, "reset err %d\n", ret);
> -		goto clk_ram_disable;
> -	}
>  
>  	regmap_update_bits(regmap, CSI_EN_REG, CSI_EN_CSI_EN, 
CSI_EN_CSI_EN);
>  
>  	return 0;
> -
> -clk_ram_disable:
> -	clk_disable_unprepare(csi_dev->clk_ram);
> -clk_mod_disable:
> -	clk_disable_unprepare(csi_dev->clk_mod);
> -	return ret;
>  }
>  
>  static enum csi_input_fmt get_csi_input_format(struct sun6i_csi_device 
*csi_dev,
> @@ -800,6 +778,65 @@ static irqreturn_t sun6i_csi_isr(int irq, void 
*private)
>  	return IRQ_HANDLED;
>  }
>  
> +static int sun6i_csi_suspend(struct device *dev)
> +{
> +	struct sun6i_csi_device *csi_dev = dev_get_drvdata(dev);
> +
> +	reset_control_assert(csi_dev->reset);
> +	clk_disable_unprepare(csi_dev->clk_ram);
> +	clk_disable_unprepare(csi_dev->clk_mod);
> +	clk_disable_unprepare(csi_dev->clk_bus);
> +
> +	return 0;
> +}
> +
> +static int sun6i_csi_resume(struct device *dev)
> +{
> +	struct sun6i_csi_device *csi_dev = dev_get_drvdata(dev);
> +	int ret;
> +
> +	ret = reset_control_deassert(csi_dev->reset);
> +	if (ret) {
> +		dev_err(dev, "failed to deassert reset\n");
> +		return ret;
> +	}
> +
> +	ret = clk_prepare_enable(csi_dev->clk_bus);
> +	if (ret) {
> +		dev_err(dev, "failed to enable bus clock\n");
> +		goto error_reset;
> +	}
> +
> +	ret = clk_prepare_enable(csi_dev->clk_mod);
> +	if (ret) {
> +		dev_err(dev, "failed to enable module clock\n");
> +		goto error_clk_bus;
> +	}
> +
> +	ret = clk_prepare_enable(csi_dev->clk_ram);
> +	if (ret) {
> +		dev_err(dev, "failed to enable ram clock\n");
> +		goto error_clk_mod;
> +	}
> +
> +	return 0;
> +
> +error_clk_mod:
> +	clk_disable_unprepare(csi_dev->clk_mod);
> +
> +error_clk_bus:
> +	clk_disable_unprepare(csi_dev->clk_bus);
> +
> +error_reset:
> +	reset_control_assert(csi_dev->reset);
> +
> +	return ret;
> +}
> +
> +static const struct dev_pm_ops sun6i_csi_pm_ops = {
> +	SET_RUNTIME_PM_OPS(sun6i_csi_suspend, sun6i_csi_resume, NULL)

Since driver depends on PM, using SET_RUNTIME_PM_OPS macro doesn't make sense.

> +};
> +
>  static const struct regmap_config sun6i_csi_regmap_config = {
>  	.reg_bits       = 32,
>  	.reg_stride     = 4,
> @@ -886,6 +923,11 @@ static int sun6i_csi_resources_setup(struct 
sun6i_csi_device *csi_dev,
>  		goto error_clk_rate_exclusive;
>  	}
>  
> +	/* Runtime PM */
> +
> +	pm_runtime_enable(dev);
> +	pm_runtime_set_suspended(dev);

pm_runtime_set_suspended() description says: "It is not valid to call this 
function for devices with runtime PM enabled."

Best regards,
Jernej

> +
>  	return 0;
>  
>  error_clk_rate_exclusive:
> @@ -896,6 +938,7 @@ static int sun6i_csi_resources_setup(struct 
sun6i_csi_device *csi_dev,
>  
>  static void sun6i_csi_resources_cleanup(struct sun6i_csi_device *csi_dev)
>  {
> +	pm_runtime_disable(csi_dev->dev);
>  	clk_rate_exclusive_put(csi_dev->clk_mod);
>  }
>  
> @@ -978,6 +1021,7 @@ static struct platform_driver sun6i_csi_platform_driver 
= {
>  	.driver	= {
>  		.name		= SUN6I_CSI_NAME,
>  		.of_match_table	= 
of_match_ptr(sun6i_csi_of_match),
> +		.pm		= &sun6i_csi_pm_ops,
>  	},
>  };
>  
> -- 
> 2.35.1
> 
>