[PATCH 04/14] drm/bridge: analogix_dp: handle clock via runtime PM

[Robert Foss]

On Fri, May 3, 2024 at 5:12 PM Lucas Stach <l.stach at pengutronix.de> wrote:
>
> There is no reason to enable the controller clock in driver probe, as
> there is no HW initialization done in this function. Instead rely on
> either runtime PM to handle the controller clock or statically enable
> it in the driver bind routine, after which real hardware access is
> required to work.
>
> Signed-off-by: Lucas Stach <l.stach at pengutronix.de>
> ---
>  .../drm/bridge/analogix/analogix_dp_core.c    | 78 +++++++++++--------
>  1 file changed, 45 insertions(+), 33 deletions(-)
>
> diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
> index 0af2a70ae5bf..9e3308257586 100644
> --- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
> +++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
> @@ -1658,8 +1658,6 @@ analogix_dp_probe(struct device *dev, struct analogix_dp_plat_data *plat_data)
>                 return ERR_CAST(dp->clock);
>         }
>
> -       clk_prepare_enable(dp->clock);
> -
>         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>
>         dp->reg_base = devm_ioremap_resource(&pdev->dev, res);
> @@ -1721,6 +1719,29 @@ analogix_dp_probe(struct device *dev, struct analogix_dp_plat_data *plat_data)
>  }
>  EXPORT_SYMBOL_GPL(analogix_dp_probe);
>
> +
> +int analogix_dp_suspend(struct analogix_dp_device *dp)
> +{
> +       clk_disable_unprepare(dp->clock);
> +
> +       return 0;
> +}
> +EXPORT_SYMBOL_GPL(analogix_dp_suspend);
> +
> +int analogix_dp_resume(struct analogix_dp_device *dp)
> +{
> +       int ret;
> +
> +       ret = clk_prepare_enable(dp->clock);
> +       if (ret < 0) {
> +               DRM_ERROR("Failed to prepare_enable the clock clk [%d]\n", ret);
> +               return ret;
> +       }
> +
> +       return 0;
> +}
> +EXPORT_SYMBOL_GPL(analogix_dp_resume);
> +
>  int analogix_dp_bind(struct analogix_dp_device *dp, struct drm_device *drm_dev)
>  {
>         int ret;
> @@ -1728,9 +1749,15 @@ int analogix_dp_bind(struct analogix_dp_device *dp, struct drm_device *drm_dev)
>         dp->drm_dev = drm_dev;
>         dp->encoder = dp->plat_data->encoder;
>
> -       pm_runtime_use_autosuspend(dp->dev);
> -       pm_runtime_set_autosuspend_delay(dp->dev, 100);
> -       pm_runtime_enable(dp->dev);
> +       if (IS_ENABLED(CONFIG_PM)) {
> +               pm_runtime_use_autosuspend(dp->dev);
> +               pm_runtime_set_autosuspend_delay(dp->dev, 100);
> +               pm_runtime_enable(dp->dev);
> +       } else {
> +               ret = analogix_dp_resume(dp);
> +               if (ret)
> +                       return ret;
> +       }
>
>         dp->aux.name = "DP-AUX";
>         dp->aux.transfer = analogix_dpaux_transfer;
> @@ -1754,8 +1781,12 @@ int analogix_dp_bind(struct analogix_dp_device *dp, struct drm_device *drm_dev)
>  err_unregister_aux:
>         drm_dp_aux_unregister(&dp->aux);
>  err_disable_pm_runtime:
> -       pm_runtime_dont_use_autosuspend(dp->dev);
> -       pm_runtime_disable(dp->dev);
> +       if (IS_ENABLED(CONFIG_PM)) {
> +               pm_runtime_dont_use_autosuspend(dp->dev);
> +               pm_runtime_disable(dp->dev);
> +       } else {
> +               analogix_dp_suspend(dp);
> +       }
>
>         return ret;
>  }
> @@ -1772,40 +1803,21 @@ void analogix_dp_unbind(struct analogix_dp_device *dp)
>         }
>
>         drm_dp_aux_unregister(&dp->aux);
> -       pm_runtime_dont_use_autosuspend(dp->dev);
> -       pm_runtime_disable(dp->dev);
> +
> +       if (IS_ENABLED(CONFIG_PM)) {
> +               pm_runtime_dont_use_autosuspend(dp->dev);
> +               pm_runtime_disable(dp->dev);
> +       } else {
> +               analogix_dp_suspend(dp);
> +       }
>  }
>  EXPORT_SYMBOL_GPL(analogix_dp_unbind);
>
>  void analogix_dp_remove(struct analogix_dp_device *dp)
>  {
> -       clk_disable_unprepare(dp->clock);
>  }
>  EXPORT_SYMBOL_GPL(analogix_dp_remove);
>
> -#ifdef CONFIG_PM
> -int analogix_dp_suspend(struct analogix_dp_device *dp)
> -{
> -       clk_disable_unprepare(dp->clock);
> -       return 0;
> -}
> -EXPORT_SYMBOL_GPL(analogix_dp_suspend);
> -
> -int analogix_dp_resume(struct analogix_dp_device *dp)
> -{
> -       int ret;
> -
> -       ret = clk_prepare_enable(dp->clock);
> -       if (ret < 0) {
> -               DRM_ERROR("Failed to prepare_enable the clock clk [%d]\n", ret);
> -               return ret;
> -       }
> -
> -       return 0;
> -}
> -EXPORT_SYMBOL_GPL(analogix_dp_resume);
> -#endif
> -
>  int analogix_dp_start_crc(struct drm_connector *connector)
>  {
>         struct analogix_dp_device *dp = to_dp(connector);
> --
> 2.39.2
>

Reviewed-by: Robert Foss <rfoss at kernel.org>