[PATCH v3 13/21] drm/bridge: Add the drm_bridge_chain_get_prev_bridge() helper

[Neil Armstrong]

On 23/10/2019 17:45, Boris Brezillon wrote:
> Will be useful for bridge drivers that want to do bus format
> negotiation with their neighbours.
> 
> Signed-off-by: Boris Brezillon <boris.brezillon at collabora.com>
> ---
> Changes in v3:
> * Inline drm_bridge_chain_get_prev_bridge()
> * Fix the doc
> 
> Changes in v2:
> * Fix the kerneldoc
> * Drop the !bridge || !bridge->encoder check
> ---
>  include/drm/drm_bridge.h | 16 ++++++++++++++++
>  1 file changed, 16 insertions(+)
> 
> diff --git a/include/drm/drm_bridge.h b/include/drm/drm_bridge.h
> index 2beb1ef9a733..3fb518494640 100644
> --- a/include/drm/drm_bridge.h
> +++ b/include/drm/drm_bridge.h
> @@ -526,6 +526,22 @@ drm_bridge_chain_get_next_bridge(struct drm_bridge *bridge)
>  	return list_next_entry(bridge, chain_node);
>  }
>  
> +/**
> + * drm_bridge_chain_get_prev_bridge() - Get the previous bridge in the chain
> + * @bridge: bridge object
> + *
> + * RETURNS:
> + * the previous bridge in the chain, or NULL if @bridge is the first.
> + */
> +static inline struct drm_bridge *
> +drm_bridge_chain_get_prev_bridge(struct drm_bridge *bridge)
> +{
> +	if (list_is_first(&bridge->chain_node, &bridge->encoder->bridge_chain))
> +		return NULL;
> +
> +	return list_prev_entry(bridge, chain_node);
> +}
> +
>  /**
>   * drm_bridge_chain_get_first_bridge() - Get the first bridge in the chain
>   * @encoder: encoder object
> 

Reviewed-by: Neil Armstrong <narmstrong at baylibre.com>