Re: [PATCH v3 03/10] drm: bridge: thc63: Report input bus mode through bridge timings

[Neil Armstrong <narmstrong@baylibre.com>]

On 28/05/2019 16:12, Laurent Pinchart wrote:
> Set a drm_bridge_timings in the drm_bridge, and use it to report the
> input bus mode (single-link or dual-link). The other fields of the
> timings structure are kept to 0 as they do not apply to LVDS buses.
> 
> Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
> Reviewed-by: Jacopo Mondi <jacopo@jmondi.org>
> Tested-by: Jacopo Mondi <jacopo+renesas@jmondi.org>
> ---
> Changes since v1:
> 
> - Ignore disabled remote device
> ---
>  drivers/gpu/drm/bridge/thc63lvd1024.c | 54 +++++++++++++++++++++------
>  1 file changed, 43 insertions(+), 11 deletions(-)
> 
> diff --git a/drivers/gpu/drm/bridge/thc63lvd1024.c b/drivers/gpu/drm/bridge/thc63lvd1024.c
> index b083a740565c..709dd28b43d6 100644
> --- a/drivers/gpu/drm/bridge/thc63lvd1024.c
> +++ b/drivers/gpu/drm/bridge/thc63lvd1024.c
> @@ -31,6 +31,8 @@ struct thc63_dev {
>  
>  	struct drm_bridge bridge;
>  	struct drm_bridge *next;
> +
> +	struct drm_bridge_timings timings;
>  };
>  
>  static inline struct thc63_dev *to_thc63(struct drm_bridge *bridge)
> @@ -48,15 +50,28 @@ static int thc63_attach(struct drm_bridge *bridge)
>  static enum drm_mode_status thc63_mode_valid(struct drm_bridge *bridge,
>  					const struct drm_display_mode *mode)
>  {
> +	struct thc63_dev *thc63 = to_thc63(bridge);
> +	unsigned int min_freq;
> +	unsigned int max_freq;
> +
>  	/*
> -	 * The THC63LVD1024 clock frequency range is 8 to 135 MHz in single-in
> -	 * mode. Note that the limits are different in dual-in, single-out mode,
> -	 * and will need to be adjusted accordingly.
> +	 * The THC63LVD1024 pixel rate range is 8 to 135 MHz in all modes but
> +	 * dual-in, single-out where it is 40 to 150 MHz. As dual-in, dual-out
> +	 * isn't supported by the driver yet, simply derive the limits from the
> +	 * input mode.
>  	 */
> -	if (mode->clock < 8000)
> +	if (thc63->timings.dual_link) {
> +		min_freq = 40000;
> +		max_freq = 150000;
> +	} else {
> +		min_freq = 8000;
> +		max_freq = 135000;
> +	}
> +
> +	if (mode->clock < min_freq)
>  		return MODE_CLOCK_LOW;
>  
> -	if (mode->clock > 135000)
> +	if (mode->clock > max_freq)
>  		return MODE_CLOCK_HIGH;
>  
>  	return MODE_OK;
> @@ -101,19 +116,19 @@ static const struct drm_bridge_funcs thc63_bridge_func = {
>  
>  static int thc63_parse_dt(struct thc63_dev *thc63)
>  {
> -	struct device_node *thc63_out;
> +	struct device_node *endpoint;
>  	struct device_node *remote;
>  
> -	thc63_out = of_graph_get_endpoint_by_regs(thc63->dev->of_node,
> -						  THC63_RGB_OUT0, -1);
> -	if (!thc63_out) {
> +	endpoint = of_graph_get_endpoint_by_regs(thc63->dev->of_node,
> +						 THC63_RGB_OUT0, -1);
> +	if (!endpoint) {
>  		dev_err(thc63->dev, "Missing endpoint in port@%u\n",
>  			THC63_RGB_OUT0);
>  		return -ENODEV;
>  	}
>  
> -	remote = of_graph_get_remote_port_parent(thc63_out);
> -	of_node_put(thc63_out);
> +	remote = of_graph_get_remote_port_parent(endpoint);
> +	of_node_put(endpoint);
>  	if (!remote) {
>  		dev_err(thc63->dev, "Endpoint in port@%u unconnected\n",
>  			THC63_RGB_OUT0);
> @@ -132,6 +147,22 @@ static int thc63_parse_dt(struct thc63_dev *thc63)
>  	if (!thc63->next)
>  		return -EPROBE_DEFER;
>  
> +	endpoint = of_graph_get_endpoint_by_regs(thc63->dev->of_node,
> +						 THC63_LVDS_IN1, -1);
> +	if (endpoint) {
> +		remote = of_graph_get_remote_port_parent(endpoint);
> +		of_node_put(endpoint);
> +
> +		if (remote) {
> +			if (of_device_is_available(remote))
> +				thc63->timings.dual_link = true;
> +			of_node_put(remote);
> +		}
> +	}
> +
> +	dev_dbg(thc63->dev, "operating in %s-link mode\n",
> +		thc63->timings.dual_link ? "dual" : "single");
> +
>  	return 0;
>  }
>  
> @@ -188,6 +219,7 @@ static int thc63_probe(struct platform_device *pdev)
>  	thc63->bridge.driver_private = thc63;
>  	thc63->bridge.of_node = pdev->dev.of_node;
>  	thc63->bridge.funcs = &thc63_bridge_func;
> +	thc63->bridge.timings = &thc63->timings;
>  
>  	drm_bridge_add(&thc63->bridge);
>  
> 

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