Re: [PATCH 2/6] drm/bridge: tc358775: Fix getting dsi host data lanes

[Michael Walle <mwalle@kernel.org>]

> The current code assume hardcoded dsi host endpoint 1, which may not
> be the case. Let's fix that and simplify the code by getting the dsi
> endpoint with of_graph_get_remote_endpoint() that does not assume any
> endpoint numbering.
> 
> Fixes: b26975593b17 ("display/drm/bridge: TC358775 DSI/LVDS driver")
> Signed-off-by: Tony Lindgren <tony@atomide.com>
> ---
>  drivers/gpu/drm/bridge/tc358775.c | 16 ++++------------
>  1 file changed, 4 insertions(+), 12 deletions(-)
> 
> diff --git a/drivers/gpu/drm/bridge/tc358775.c b/drivers/gpu/drm/bridge/tc358775.c
> --- a/drivers/gpu/drm/bridge/tc358775.c
> +++ b/drivers/gpu/drm/bridge/tc358775.c
> @@ -528,25 +528,17 @@ tc_mode_valid(struct drm_bridge *bridge,
>  static int tc358775_parse_dt(struct device_node *np, struct tc_data *tc)
>  {
>  	struct device_node *endpoint;
> -	struct device_node *parent;
>  	struct device_node *remote;
>  	int dsi_lanes = -1;
>  
> -	/*
> -	 * To get the data-lanes of dsi, we need to access the dsi0_out of port1
> -	 *  of dsi0 endpoint from bridge port0 of d2l_in
> -	 */
>  	endpoint = of_graph_get_endpoint_by_regs(tc->dev->of_node,
>  						 TC358775_DSI_IN, -1);
>  	if (endpoint) {
> -		/* dsi0_out node */
> -		parent = of_graph_get_remote_port_parent(endpoint);
> +		/* Get the configured data lanes on the dsi host side */
> +		remote = of_graph_get_remote_endpoint(endpoint);
>  		of_node_put(endpoint);
> -		if (parent) {
> -			/* dsi0 port 1 */
> -			dsi_lanes = drm_of_get_data_lanes_count_ep(parent, 1, -1, 1, 4);
> -			of_node_put(parent);
> -		}
> +		dsi_lanes = drm_of_get_data_lanes_count(remote, 1, 4);

I actually have the same fix, but with one additional detail, which I'm
unsure about though: This looks at the data-lanes property of the *remote*
endpoint whereas other bridge drivers (see tc358767, ti-sn65dsi83, lt8912b,
anx7625) look at the local endpoint and I'm not sure what is correct.

-michael