drm: add drm_of_encoder_active_endpoint helpers
This patch adds a helper to parse the encoder endpoint connected to the
encoder's crtc and two helpers to return its id and port id.
This can be used to determine input mux setting from endpoint or port ids.
Suggested-by: Daniel Kurtz <djkurtz@chromium.org>
Reviewed-by: Daniel Kurtz <djkurtz@chromium.org>
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
diff --git a/drivers/gpu/drm/drm_of.c b/drivers/gpu/drm/drm_of.c
index 493c05c..bc98bb9 100644
--- a/drivers/gpu/drm/drm_of.c
+++ b/drivers/gpu/drm/drm_of.c
@@ -149,3 +149,37 @@
return component_master_add_with_match(dev, m_ops, match);
}
EXPORT_SYMBOL(drm_of_component_probe);
+
+/*
+ * drm_of_encoder_active_endpoint - return the active encoder endpoint
+ * @node: device tree node containing encoder input ports
+ * @encoder: drm_encoder
+ *
+ * Given an encoder device node and a drm_encoder with a connected crtc,
+ * parse the encoder endpoint connecting to the crtc port.
+ */
+int drm_of_encoder_active_endpoint(struct device_node *node,
+ struct drm_encoder *encoder,
+ struct of_endpoint *endpoint)
+{
+ struct device_node *ep;
+ struct drm_crtc *crtc = encoder->crtc;
+ struct device_node *port;
+ int ret;
+
+ if (!node || !crtc)
+ return -EINVAL;
+
+ for_each_endpoint_of_node(node, ep) {
+ port = of_graph_get_remote_port(ep);
+ of_node_put(port);
+ if (port == crtc->port) {
+ ret = of_graph_parse_endpoint(ep, endpoint);
+ of_node_put(ep);
+ return ret;
+ }
+ }
+
+ return -EINVAL;
+}
+EXPORT_SYMBOL_GPL(drm_of_encoder_active_endpoint);