Re: [PATCH v2 02/12] sun4i/drm: backend: Document the engine operations

[Chen-Yu Tsai]

On Mon, Dec 18, 2017 at 10:57 PM, Maxime Ripard
<maxime.ripard@xxxxxxxxxxxxxxxxxx> wrote:
> Our operations were missing some documentation to explain what was expected
> from them.
>
> Let's make that clearer.
>
> Signed-off-by: Maxime Ripard <maxime.ripard@xxxxxxxxxxxxxxxxxx>
> ---
>  drivers/gpu/drm/sun4i/sun4i_backend.c |  2 +-
>  drivers/gpu/drm/sun4i/sunxi_engine.h  | 51 ++++++++++++++++++++++++++--
>  2 files changed, 50 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/gpu/drm/sun4i/sun4i_backend.c b/drivers/gpu/drm/sun4i/sun4i_backend.c
> index c99d1a7e815a..f971d3fb5ee4 100644
> --- a/drivers/gpu/drm/sun4i/sun4i_backend.c
> +++ b/drivers/gpu/drm/sun4i/sun4i_backend.c
> @@ -93,7 +93,7 @@ void sun4i_backend_layer_enable(struct sun4i_backend *backend,
>  static int sun4i_backend_drm_format_to_layer(struct drm_plane *plane,
>                                              u32 format, u32 *mode)
>  {
> -       if ((plane->type == DRM_PLANE_TYPE_PRIMARY) &&
> +       if (plane && (plane->type == DRM_PLANE_TYPE_PRIMARY) &&
>             (format == DRM_FORMAT_ARGB8888))
>                 format = DRM_FORMAT_XRGB8888;

Stray hunk?

>
> diff --git a/drivers/gpu/drm/sun4i/sunxi_engine.h b/drivers/gpu/drm/sun4i/sunxi_engine.h
> index 4cb70ae65c79..36c8388b1646 100644
> --- a/drivers/gpu/drm/sun4i/sunxi_engine.h
> +++ b/drivers/gpu/drm/sun4i/sunxi_engine.h
> @@ -15,13 +15,60 @@ struct drm_device;
>
>  struct sunxi_engine;
>
> +/**
> + * struct sunxi_engine_ops - helper operations for sunXi engines
> + *
> + * These hooks are used by the common part of the DRM driver to
> + * implement the proper behaviour.
> + */
>  struct sunxi_engine_ops {
> +       /**
> +        * @apply_color_correction:
> +        *
> +        * This callback will enable the color correction in the
> +        * backend. This is useful only for the composite output.
> +        *
> +        * This function is optional.
> +        */
> +       void (*apply_color_correction)(struct sunxi_engine *engine);
> +
> +       /**
> +        * @commit:
> +        *
> +        * This callback will trigger the hardware switch to commit
> +        * the new configuration that has been setup during the next
> +        * vblank period.
> +        *
> +        * This function is optional.
> +        */
>         void (*commit)(struct sunxi_engine *engine);
> +
> +       /**
> +        * @disable_color_correction:
> +        *
> +        * This callback will stop the color correction in the
> +        * backend. This is useful only for the composite output.
> +        *
> +        * This function is optional.
> +        */
> +       void (*disable_color_correction)(struct sunxi_engine *engine);
> +
> +       /**
> +        * @layers_init:
> +        *
> +        * This callback is used to allocate, initialize and register
> +        * the layers supported by that backend.
> +        *
> +        * This function is mandatory.
> +        *
> +        * RETURNS:
> +        *
> +        * The array of struct drm_plane backing the layers, or an
> +        * error pointer on failure.
> +        */
>         struct drm_plane **(*layers_init)(struct drm_device *drm,
>                                           struct sunxi_engine *engine);
>
> -       void (*apply_color_correction)(struct sunxi_engine *engine);
> -       void (*disable_color_correction)(struct sunxi_engine *engine);

I think keeping the grouping would make more sense, i.e. have the
enable/disable ops placed together.

Otherwise,
Reviewed-by: Chen-Yu Tsai <wens@xxxxxxxx>

>  };
>
>  /**
> --
> git-series 0.9.1