Re: [PATCH 1/8] drm: bridge: Add support for static image formats

[Peter Rosin]

On 2018-04-19 11:31, Jacopo Mondi wrote:
> Add support for storing image format information in DRM bridges with
> associated helper function.
> 
> This patch replicates for bridges what 'drm_display_info_set_bus_formats()'
> is for connectors.
> 
> Signed-off-by: Jacopo Mondi <jacopo+renesas@xxxxxxxxxx>
> ---
>  drivers/gpu/drm/drm_bridge.c | 30 ++++++++++++++++++++++++++++++
>  include/drm/drm_bridge.h     |  8 ++++++++
>  2 files changed, 38 insertions(+)
> 
> diff --git a/drivers/gpu/drm/drm_bridge.c b/drivers/gpu/drm/drm_bridge.c
> index 1638bfe..e2ad098 100644
> --- a/drivers/gpu/drm/drm_bridge.c
> +++ b/drivers/gpu/drm/drm_bridge.c
> @@ -157,6 +157,36 @@ void drm_bridge_detach(struct drm_bridge *bridge)
>  }
>  
>  /**
> + * drm_bridge_set_bus_formats() - set bridge supported image formats
> + * @bridge: the bridge to set image formats in
> + * @formats: array of MEDIA_BUS_FMT\_ supported image formats
> + * @num_formats: number of elements in the @formats array
> + *
> + * Store a list of supported image formats in a bridge.
> + * See MEDIA_BUS_FMT_* definitions in include/uapi/linux/media-bus-format.h for
> + * a full list of available formats.
> + */
> +int drm_bridge_set_bus_formats(struct drm_bridge *bridge, const u32 *formats,
> +			       unsigned int num_formats)
> +{
> +	u32 *fmts;
> +
> +	if (!formats || !num_formats)
> +		return -EINVAL;

I see no compelling reason to forbid restoring the number of reported
input formats to zero? I can't think of a use right now of course, but it
seems a bit odd all the same.

Cheers,
Peter

> +
> +	fmts = kmemdup(formats, sizeof(*formats) * num_formats, GFP_KERNEL);
> +	if (!fmts)
> +		return -ENOMEM;
> +
> +	kfree(bridge->bus_formats);
> +	bridge->bus_formats = fmts;
> +	bridge->num_bus_formats = num_formats;
> +
> +	return 0;
> +}
> +EXPORT_SYMBOL(drm_bridge_set_bus_formats);
> +
> +/**
>   * DOC: bridge callbacks
>   *
>   * The &drm_bridge_funcs ops are populated by the bridge driver. The DRM
> diff --git a/include/drm/drm_bridge.h b/include/drm/drm_bridge.h
> index 3270fec..6b3648c 100644
> --- a/include/drm/drm_bridge.h
> +++ b/include/drm/drm_bridge.h
> @@ -258,6 +258,9 @@ struct drm_bridge_timings {
>   * @encoder: encoder to which this bridge is connected
>   * @next: the next bridge in the encoder chain
>   * @of_node: device node pointer to the bridge
> + * @bus_formats: wire image formats. Array of @num_bus_formats MEDIA_BUS_FMT\_
> + * elements
> + * @num_bus_formats: size of @bus_formats array
>   * @list: to keep track of all added bridges
>   * @timings: the timing specification for the bridge, if any (may
>   * be NULL)
> @@ -271,6 +274,9 @@ struct drm_bridge {
>  #ifdef CONFIG_OF
>  	struct device_node *of_node;
>  #endif
> +	const u32 *bus_formats;
> +	unsigned int num_bus_formats;
> +
>  	struct list_head list;
>  	const struct drm_bridge_timings *timings;
>  
> @@ -296,6 +302,8 @@ void drm_bridge_mode_set(struct drm_bridge *bridge,
>  			struct drm_display_mode *adjusted_mode);
>  void drm_bridge_pre_enable(struct drm_bridge *bridge);
>  void drm_bridge_enable(struct drm_bridge *bridge);
> +int drm_bridge_set_bus_formats(struct drm_bridge *bridge, const u32 *fmts,
> +			       unsigned int num_fmts);
>  
>  #ifdef CONFIG_DRM_PANEL_BRIDGE
>  struct drm_bridge *drm_panel_bridge_add(struct drm_panel *panel,
>