Re: [PATCH 3/3] drm/tilcdc: Add drm bridge support for attaching drm bridge drivers

[Laurent Pinchart <laurent.pinchart@ideasonboard.com>]

Hi Jyri,

Thank you for the patch.

On Wednesday 02 Nov 2016 18:32:17 Jyri Sarha wrote:
> Adds drm bride support for attaching drm bridge drivers to tilcdc. The
> decision whether a video port leads to an external encoder or bridge
> is made simply based on remote device's compatible string. The code
> has been tested with BeagleBone-Black with and without BeagleBone
> DVI-D Cape Rev A3 using ti-tfp410 driver.
> 
> Signed-off-by: Jyri Sarha <jsarha@ti.com>
> ---
>  .../devicetree/bindings/display/tilcdc/tilcdc.txt  |   7 +-
>  drivers/gpu/drm/tilcdc/tilcdc_drv.c                |   7 +-
>  drivers/gpu/drm/tilcdc/tilcdc_drv.h                |   2 +
>  drivers/gpu/drm/tilcdc/tilcdc_external.c           | 140 ++++++++++++++---
>  drivers/gpu/drm/tilcdc/tilcdc_external.h           |   1 +
>  5 files changed, 135 insertions(+), 22 deletions(-)
> 
> diff --git a/Documentation/devicetree/bindings/display/tilcdc/tilcdc.txt
> b/Documentation/devicetree/bindings/display/tilcdc/tilcdc.txt index
> 6fddb4f..ae7a942 100644
> --- a/Documentation/devicetree/bindings/display/tilcdc/tilcdc.txt
> +++ b/Documentation/devicetree/bindings/display/tilcdc/tilcdc.txt
> @@ -34,9 +34,10 @@ Optional properties:
> 
>  Optional nodes:
> 
> - - port/ports: to describe a connection to an external encoder. The
> -   binding follows Documentation/devicetree/bindings/graph.txt and
> -   suppors a single port with a single endpoint.
> + - port/ports: to describe a connection to an external encoder or
> +   bridge. The binding follows

What's the difference between encoder and bridge here ? drm_bridge and 
drm_encoder are irrelevant to DT bindings, we should only care about the 
hardware view of the system here.

> +   Documentation/devicetree/bindings/graph.txt and suppors a single
> +   port with a single endpoint.
> 
>   - See also Documentation/devicetree/bindings/display/tilcdc/panel.txt and
>     Documentation/devicetree/bindings/display/tilcdc/tfp410.txt for
> connecting diff --git a/drivers/gpu/drm/tilcdc/tilcdc_drv.c
> b/drivers/gpu/drm/tilcdc/tilcdc_drv.c index dcc9621..ec22576 100644
> --- a/drivers/gpu/drm/tilcdc/tilcdc_drv.c
> +++ b/drivers/gpu/drm/tilcdc/tilcdc_drv.c
> @@ -384,9 +384,14 @@ static int tilcdc_init(struct drm_driver *ddrv, struct
> device *dev) ret = tilcdc_add_external_encoders(ddev);
>  		if (ret < 0)
>  			goto init_failed;
> +	} else {
> +		ret = tilcdc_attach_remote_device(ddev);
> +		if (ret)
> +			goto init_failed;
>  	}
> 
> -	if ((priv->num_encoders == 0) || (priv->num_connectors == 0)) {
> +	if (!priv->remote_encoder &&
> +	    ((priv->num_encoders == 0) || (priv->num_connectors == 0))) {
>  		dev_err(dev, "no encoders/connectors found\n");
>  		ret = -ENXIO;
>  		goto init_failed;
> diff --git a/drivers/gpu/drm/tilcdc/tilcdc_drv.h
> b/drivers/gpu/drm/tilcdc/tilcdc_drv.h index d31fe5d..283ff28 100644
> --- a/drivers/gpu/drm/tilcdc/tilcdc_drv.h
> +++ b/drivers/gpu/drm/tilcdc/tilcdc_drv.h
> @@ -90,6 +90,8 @@ struct tilcdc_drm_private {
>  	struct drm_connector *connectors[8];
>  	const struct drm_connector_helper_funcs *connector_funcs[8];
> 
> +	struct drm_encoder *remote_encoder;
> +
>  	bool is_registered;
>  	bool is_componentized;
>  };
> diff --git a/drivers/gpu/drm/tilcdc/tilcdc_external.c
> b/drivers/gpu/drm/tilcdc/tilcdc_external.c index 06a4c58..bcb1324 100644
> --- a/drivers/gpu/drm/tilcdc/tilcdc_external.c
> +++ b/drivers/gpu/drm/tilcdc/tilcdc_external.c
> @@ -28,6 +28,18 @@
>  		.raster_order           = 0,
>  };
> 
> +static const struct tilcdc_panel_info panel_info_default = {
> +		.ac_bias                = 255,
> +		.ac_bias_intrpt         = 0,
> +		.dma_burst_sz           = 16,
> +		.bpp                    = 16,
> +		.fdd                    = 0x80,
> +		.tft_alt_mode           = 0,
> +		.sync_edge              = 0,
> +		.sync_ctrl              = 1,
> +		.raster_order           = 0,
> +};
> +
>  static int tilcdc_external_mode_valid(struct drm_connector *connector,
>  				      struct drm_display_mode *mode)
>  {
> @@ -130,6 +142,101 @@ void tilcdc_remove_external_encoders(struct drm_device
> *dev) priv->connector_funcs[i]);
>  }
> 
> +static struct drm_encoder_funcs tilcdc_remote_encoder_funcs = {
> +	.destroy	= drm_encoder_cleanup,
> +};
> +
> +static
> +int tilcdc_attach_bridge(struct drm_device *ddev, struct drm_bridge
> *bridge) +{
> +	struct tilcdc_drm_private *priv = ddev->dev_private;
> +	int ret;
> +
> +	priv->remote_encoder->possible_crtcs = BIT(0);
> +	priv->remote_encoder->bridge = bridge;
> +	bridge->encoder = priv->remote_encoder;
> +
> +	ret = drm_bridge_attach(ddev, bridge);
> +	if (ret) {
> +		dev_err(ddev->dev, "drm_bridge_attach() failed %d\n", ret);
> +		return ret;
> +	}
> +
> +	tilcdc_crtc_set_panel_info(priv->crtc, &panel_info_default);
> +
> +	return 0;
> +}
> +
> +static int tilcdc_node_has_port(struct device_node *dev_node)
> +{
> +	struct device_node *node;
> +
> +	node = of_get_child_by_name(dev_node, "ports");
> +	if (!node)
> +		node = of_get_child_by_name(dev_node, "port");
> +	if (!node)
> +		return 0;
> +	of_node_put(node);
> +
> +	return 1;
> +}
> +
> +static
> +struct device_node *tilcdc_get_remote_node(struct device_node *node)
> +{
> +	struct device_node *ep;
> +	struct device_node *parent;
> +
> +	if (!tilcdc_node_has_port(node))
> +		return NULL;
> +
> +	ep = of_graph_get_next_endpoint(node, NULL);
> +	if (!ep)
> +		return NULL;
> +
> +	parent = of_graph_get_remote_port_parent(ep);
> +	of_node_put(ep);
> +
> +	return parent;
> +}
> +
> +int tilcdc_attach_remote_device(struct drm_device *ddev)
> +{
> +	struct tilcdc_drm_private *priv = ddev->dev_private;
> +	struct device_node *remote_node;
> +	struct drm_bridge *bridge;
> +	int ret;
> +
> +	remote_node = tilcdc_get_remote_node(ddev->dev->of_node);
> +	if (!remote_node)
> +		return 0;
> +
> +	bridge = of_drm_find_bridge(remote_node);
> +	of_node_put(remote_node);
> +	if (!bridge)
> +		return -EPROBE_DEFER;
> +
> +	priv->remote_encoder = devm_kzalloc(ddev->dev,
> +					    sizeof(*priv->remote_encoder),
> +					    GFP_KERNEL);
> +	if (!priv->remote_encoder)
> +		return -ENOMEM;
> +
> +	ret = drm_encoder_init(ddev, priv->remote_encoder,
> +			       &tilcdc_remote_encoder_funcs,
> +			       DRM_MODE_ENCODER_NONE, NULL);
> +	if (ret) {
> +		dev_err(ddev->dev, "drm_encoder_init() failed %d\n", ret);
> +		return ret;
> +	}
> +
> +	ret = tilcdc_attach_bridge(ddev, bridge);
> +	if (ret)
> +		drm_encoder_cleanup(priv->remote_encoder);
> +
> +	return ret;
> +}
> +
>  static int dev_match_of(struct device *dev, void *data)
>  {
>  	return dev->of_node == data;
> @@ -141,16 +248,10 @@ int tilcdc_get_external_components(struct device *dev,
> struct device_node *node;
>  	struct device_node *ep = NULL;
>  	int count = 0;
> +	int ret = 0;
> 
> -	/* Avoid error print by of_graph_get_next_endpoint() if there
> -	 * is no ports present.
> -	 */
> -	node = of_get_child_by_name(dev->of_node, "ports");
> -	if (!node)
> -		node = of_get_child_by_name(dev->of_node, "port");
> -	if (!node)
> +	if (!tilcdc_node_has_port(dev->of_node))
>  		return 0;
> -	of_node_put(node);
> 
>  	while ((ep = of_graph_get_next_endpoint(dev->of_node, ep))) {
>  		node = of_graph_get_remote_port_parent(ep);
> @@ -160,17 +261,20 @@ int tilcdc_get_external_components(struct device *dev,
> }
> 
>  		dev_dbg(dev, "Subdevice node '%s' found\n", node->name);
> -		if (match)
> -			drm_of_component_match_add(dev, match, dev_match_of,
> -						   node);
> -		of_node_put(node);
> -		count++;
> -	}
> 
> -	if (count > 1) {
> -		dev_err(dev, "Only one external encoder is supported\n");
> -		return -EINVAL;
> +		if (of_device_is_compatible(node, "nxp,tda998x")) {
> +			if (match)
> +				drm_of_component_match_add(dev, match,
> +							   dev_match_of, 
node);
> +			ret = 1;
> +		}
> +
> +		of_node_put(node);
> +		if (count++ > 1) {
> +			dev_err(dev, "Only one port is supported\n");
> +			return -EINVAL;
> +		}
>  	}
> 
> -	return count;
> +	return ret;
>  }
> diff --git a/drivers/gpu/drm/tilcdc/tilcdc_external.h
> b/drivers/gpu/drm/tilcdc/tilcdc_external.h index c700e0c..a27c365 100644
> --- a/drivers/gpu/drm/tilcdc/tilcdc_external.h
> +++ b/drivers/gpu/drm/tilcdc/tilcdc_external.h
> @@ -22,4 +22,5 @@
>  void tilcdc_remove_external_encoders(struct drm_device *dev);
>  int tilcdc_get_external_components(struct device *dev,
>  				   struct component_match **match);
> +int tilcdc_attach_remote_device(struct drm_device *ddev);
>  #endif /* __TILCDC_SLAVE_H__ */

-- 
Regards,

Laurent Pinchart

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