[PATCH v2 3/5] video: Introduce video_sync operation

[Simon Glass]

On Mon, 14 Dec 2020 at 01:38, Michal Simek <michal.simek at xilinx.com> wrote:
>
> Some drivers like LCD connected via SPI requires explicit sync function
> which copy framebuffer content over SPI to controller to display.
> This hook doesn't exist yet that's why introduce it via video operations.
>
> Signed-off-by: Michal Simek <michal.simek at xilinx.com>
> ---
>
> Changes in v2:
> - Add support for returning value
> - Update kernel-doc format to pass kernel-doc script
> - Update patch subject s/call/operation/
>
> Simon: Please review this. I didn't find existing way how this can be done
> that's why I am introducing this hook. Also maybe name can be named a
> little bit differently. That's why waiting for better suggestion.
>
> ---
>  drivers/video/video-uclass.c |  9 +++++++++
>  include/video.h              | 12 ++++++++++--
>  2 files changed, 19 insertions(+), 2 deletions(-)

Reviewed-by: Simon Glass <sjg at chromium.org>

>
> diff --git a/drivers/video/video-uclass.c b/drivers/video/video-uclass.c
> index 6fc412801714..938e7d371311 100644
> --- a/drivers/video/video-uclass.c
> +++ b/drivers/video/video-uclass.c
> @@ -175,6 +175,15 @@ void video_set_default_colors(struct udevice *dev, bool invert)
>  /* Flush video activity to the caches */
>  int video_sync(struct udevice *vid, bool force)
>  {
> +       struct video_ops *ops = video_get_ops(vid);
> +       int ret;
> +
> +       if (ops && ops->video_sync) {
> +               ret = ops->video_sync(vid);
> +               if (ret)
> +                       return ret;
> +       }
> +
>         /*
>          * flush_dcache_range() is declared in common.h but it seems that some
>          * architectures do not actually implement it. Is there a way to find
> diff --git a/include/video.h b/include/video.h
> index 1bfe6843a805..12fc525ab4ef 100644
> --- a/include/video.h
> +++ b/include/video.h
> @@ -114,8 +114,16 @@ struct video_priv {
>         u8 bg_col_idx;
>  };
>
> -/* Placeholder - there are no video operations at present */
> +/**
> + * struct video_ops - structure for keeping video operations
> + * @video_sync: Synchronize FB with device. Some device like SPI based LCD
> + *             displays needs synchronization when data in an FB is available.
> + *             For these devices implement video_sync hook to call a sync
> + *             function. vid is pointer to video device udevice. Function
> + *             should return 0 on success video_sync and error code otherwise

Can this go before the video_sync, below?


> + */
>  struct video_ops {
> +       int (*video_sync)(struct udevice *vid);
>  };
>
>  #define video_get_ops(dev)        ((struct video_ops *)(dev)->driver->ops)
> @@ -155,7 +163,7 @@ int video_clear(struct udevice *dev);
>   * @force:     True to force a sync even if there was one recently (this is
>   *             very expensive on sandbox)
>   *
> - * @return: 0 always
> + * @return: 0 on success, error code otherwise
>   *
>   * Some frame buffers are cached or have a secondary frame buffer. This
>   * function syncs these up so that the current contents of the U-Boot frame
> --
> 2.29.2
>