[PATCH] drm/mediatek: ensure bridge disable happends before suspend

[CK Hu]

Hi, Hsin-yi:

On Thu, 2022-06-30 at 03:05 +0800, Hsin-Yi Wang wrote:
> Make sure bridge_disable will be called before suspend by calling
> drm_mode_config_helper_suspend() in .prepare callback.

Reviewed-by: CK Hu <ck.hu at mediatek.com>

> 
> Signed-off-by: Hsin-Yi Wang <hsinyi at chromium.org>
> ---
> The issue is found if suspend is called via VT2 in several MTK SoC
> (eg.
> MT8173, MT8183, MT8186) chromebook boards with eDP bridge:
> bridge disable is called through mtk-drm's suspend, and it needs to
> be
> called before bridge pm runtime suspend.
> So we move the hook to .prepare() and .complete().
> ---
>  drivers/gpu/drm/mediatek/mtk_drm_drv.c | 16 ++++++++--------
>  1 file changed, 8 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/gpu/drm/mediatek/mtk_drm_drv.c
> b/drivers/gpu/drm/mediatek/mtk_drm_drv.c
> index 13a1bbe7ead7f..a42812e490007 100644
> --- a/drivers/gpu/drm/mediatek/mtk_drm_drv.c
> +++ b/drivers/gpu/drm/mediatek/mtk_drm_drv.c
> @@ -828,8 +828,7 @@ static int mtk_drm_remove(struct platform_device
> *pdev)
>  	return 0;
>  }
>  
> -#ifdef CONFIG_PM_SLEEP
> -static int mtk_drm_sys_suspend(struct device *dev)
> +static int mtk_drm_sys_prepare(struct device *dev)
>  {
>  	struct mtk_drm_private *private = dev_get_drvdata(dev);
>  	struct drm_device *drm = private->drm;
> @@ -840,20 +839,21 @@ static int mtk_drm_sys_suspend(struct device
> *dev)
>  	return ret;
>  }
>  
> -static int mtk_drm_sys_resume(struct device *dev)
> +static void mtk_drm_sys_complete(struct device *dev)
>  {
>  	struct mtk_drm_private *private = dev_get_drvdata(dev);
>  	struct drm_device *drm = private->drm;
>  	int ret;
>  
>  	ret = drm_mode_config_helper_resume(drm);
> -
> -	return ret;
> +	if (ret)
> +		dev_err(dev, "Failed to resume\n");
>  }
> -#endif
>  
> -static SIMPLE_DEV_PM_OPS(mtk_drm_pm_ops, mtk_drm_sys_suspend,
> -			 mtk_drm_sys_resume);
> +static const struct dev_pm_ops mtk_drm_pm_ops = {
> +	.prepare = mtk_drm_sys_prepare,
> +	.complete = mtk_drm_sys_complete,
> +};
>  
>  static struct platform_driver mtk_drm_platform_driver = {
>  	.probe	= mtk_drm_probe,