Hi Laurent,
On Sat, Mar 02, 2019 at 06:17:25PM +0200, Laurent Pinchart wrote:
> The R-Car DU driver assumes that a bridge is always connected to the DU
> output. This is valid for the LVDS and HDMI outputs, but the DPAD
> outputs can be connected directly to a panel, in which case no bridge is
> available.
>
> To support this use case, detect whether the entities connected to the
> DU DPAD outputs are encoders or panels based on the number of ports of
> their DT node, and retrieve the corresponding type of DRM objects. For
> panels, additionally create panel bridge instances.
>
> Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@xxxxxxxxxxxxxxxx>
> ---
> drivers/gpu/drm/rcar-du/rcar_du_encoder.c | 54 ++++++++++++++++++++---
> 1 file changed, 48 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/gpu/drm/rcar-du/rcar_du_encoder.c b/drivers/gpu/drm/rcar-du/rcar_du_encoder.c
> index 8ee4e762f4e5..595ecfa1ff0e 100644
> --- a/drivers/gpu/drm/rcar-du/rcar_du_encoder.c
> +++ b/drivers/gpu/drm/rcar-du/rcar_du_encoder.c
> @@ -28,13 +28,33 @@ static const struct drm_encoder_funcs encoder_funcs = {
> .destroy = drm_encoder_cleanup,
> };
>
> +static unsigned int rcar_du_encoder_count_ports(struct device_node *node)
> +{
> + struct device_node *ports;
> + struct device_node *port;
> + unsigned int num_ports = 0;
> +
> + ports = of_get_child_by_name(node, "ports");
> + if (!ports)
> + ports = of_node_get(node);
> +
> + for_each_child_of_node(ports, port) {
> + if (of_node_name_eq(port, "port"))
> + num_ports++;
> + }
> +
> + of_node_put(node);
> +
> + return num_ports;
> +}
> +
> int rcar_du_encoder_init(struct rcar_du_device *rcdu,
> enum rcar_du_output output,
> struct device_node *enc_node)
> {
You received a Tested-by, so I might surely be mistaken, but the
caller of this function skips all remote nodes with a single port,
doesn't it?
https://elixir.bootlin.com/linux/latest/source/drivers/gpu/drm/rcar-du/rcar_du_kms.c#L308
I don't have any DTS with a panel connected to the DPAD output so, as
a test, I removed all endpoints except endpoint@0 from the 'hdmi0' device
node, and the 'rcar_du_encoder_init()' function never gets called and DU
probing fails with:
rcar-du feb00000.display: no encoder found for endpoint /soc/display@feb00000/ports/port@1/endpoint, skipping
What am I missing?
Thanks
j
> struct rcar_du_encoder *renc;
> struct drm_encoder *encoder;
> - struct drm_bridge *bridge = NULL;
> + struct drm_bridge *bridge;
> int ret;
>
> renc = devm_kzalloc(rcdu->dev, sizeof(*renc), GFP_KERNEL);
> @@ -48,11 +68,33 @@ int rcar_du_encoder_init(struct rcar_du_device *rcdu,
> dev_dbg(rcdu->dev, "initializing encoder %pOF for output %u\n",
> enc_node, output);
>
> - /* Locate the DRM bridge from the encoder DT node. */
> - bridge = of_drm_find_bridge(enc_node);
> - if (!bridge) {
> - ret = -EPROBE_DEFER;
> - goto done;
> + /*
> + * Locate the DRM bridge from the DT node. For the DPAD outputs, if the
> + * DT node has a single port, consider it describes a panel and create a
> + * panel bridge.
> + */
> + if ((output == RCAR_DU_OUTPUT_DPAD0 ||
> + output == RCAR_DU_OUTPUT_DPAD1) &&
> + rcar_du_encoder_count_ports(enc_node) == 1) {
Could this be cached?
> + struct drm_panel *panel = of_drm_find_panel(enc_node);
> +
> + if (IS_ERR(panel)) {
> + ret = PTR_ERR(panel);
> + goto done;
> + }
> +
> + bridge = devm_drm_panel_bridge_add(rcdu->dev, panel,
> + DRM_MODE_CONNECTOR_DPI);
> + if (IS_ERR(bridge)) {
> + ret = PTR_ERR(bridge);
> + goto done;
> + }
> + } else {
> + bridge = of_drm_find_bridge(enc_node);
> + if (!bridge) {
> + ret = -EPROBE_DEFER;
> + goto done;
> + }
> }
>
> ret = drm_encoder_init(rcdu->ddev, encoder, &encoder_funcs,
> --
> Regards,
>
> Laurent Pinchart
>
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