[PATCH] drm/atmel-hlcdc: Fix output initialization

[Alexandre Belloni]

On 18/05/2017 at 14:35:21 +0200, Boris Brezillon wrote:
> drm_of_find_panel_or_bridge() is expecting np to point to the encoder
> node, not the bridge or panel this encoder is feeding.
> Moreover, the endpoint parameter passed to drm_of_find_panel_or_bridge()
> is always set to zero, which prevents us from probing all outputs.
> 
> We also move the atmel_hlcdc_rgb_output allocation after the
> panel/bridge detection to avoid useless allocations.
> 
> Reported-by: Alexandre Belloni <alexandre.belloni at free-electrons.com>
Tested-by: Alexandre Belloni <alexandre.belloni at free-electrons.com>

> Fixes: ebc944613567 ("drm: convert drivers to use drm_of_find_panel_or_bridge")
> Signed-off-by: Boris Brezillon <boris.brezillon at free-electrons.com>
> ---
>  drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_output.c | 36 +++++++++---------------
>  1 file changed, 14 insertions(+), 22 deletions(-)
> 
> diff --git a/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_output.c b/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_output.c
> index 65a3bd7a0c00..423dda2785d4 100644
> --- a/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_output.c
> +++ b/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_output.c
> @@ -152,8 +152,7 @@ static const struct drm_connector_funcs atmel_hlcdc_panel_connector_funcs = {
>  	.atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
>  };
>  
> -static int atmel_hlcdc_attach_endpoint(struct drm_device *dev,
> -				       const struct device_node *np)
> +static int atmel_hlcdc_attach_endpoint(struct drm_device *dev, int endpoint)
>  {
>  	struct atmel_hlcdc_dc *dc = dev->dev_private;
>  	struct atmel_hlcdc_rgb_output *output;
> @@ -161,6 +160,11 @@ static int atmel_hlcdc_attach_endpoint(struct drm_device *dev,
>  	struct drm_bridge *bridge;
>  	int ret;
>  
> +	ret = drm_of_find_panel_or_bridge(dev->dev->of_node, 0, endpoint,
> +					  &panel, &bridge);
> +	if (ret)
> +		return ret;
> +
>  	output = devm_kzalloc(dev->dev, sizeof(*output), GFP_KERNEL);
>  	if (!output)
>  		return -EINVAL;
> @@ -177,10 +181,6 @@ static int atmel_hlcdc_attach_endpoint(struct drm_device *dev,
>  
>  	output->encoder.possible_crtcs = 0x1;
>  
> -	ret = drm_of_find_panel_or_bridge(np, 0, 0, &panel, &bridge);
> -	if (ret)
> -		return ret;
> -
>  	if (panel) {
>  		output->connector.dpms = DRM_MODE_DPMS_OFF;
>  		output->connector.polled = DRM_CONNECTOR_POLL_CONNECT;
> @@ -220,22 +220,14 @@ static int atmel_hlcdc_attach_endpoint(struct drm_device *dev,
>  
>  int atmel_hlcdc_create_outputs(struct drm_device *dev)
>  {
> -	struct device_node *remote;
> -	int ret = -ENODEV;
> -	int endpoint = 0;
> -
> -	while (true) {
> -		/* Loop thru possible multiple connections to the output */
> -		remote = of_graph_get_remote_node(dev->dev->of_node, 0,
> -						  endpoint++);
> -		if (!remote)
> -			break;
> -
> -		ret = atmel_hlcdc_attach_endpoint(dev, remote);
> -		of_node_put(remote);
> -		if (ret)
> -			return ret;
> -	}
> +	int endpoint, ret = 0;
> +
> +	for (endpoint = 0; !ret; endpoint++)
> +		ret = atmel_hlcdc_attach_endpoint(dev, endpoint);
> +
> +	/* At least one device was successfully attached.*/
> +	if (ret == -ENODEV && endpoint)
> +		return 0;
>  
>  	return ret;
>  }
> -- 
> 2.7.4
> 

-- 
Alexandre Belloni, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com