@@ -275,3 +275,119 @@ int drm_of_find_panel_or_bridge(const struct device_node *np,
return ret;
}
EXPORT_SYMBOL_GPL(drm_of_find_panel_or_bridge);
+
+enum drm_of_lvds_pixels {
+ DRM_OF_LVDS_EVEN = BIT(0),
+ DRM_OF_LVDS_ODD = BIT(1),
+};
+
+static int drm_of_lvds_get_port_pixels_type(struct device_node *port_node)
+{
+ bool even_pixels =
+ of_property_read_bool(port_node, "dual-lvds-even-pixels");
+ bool odd_pixels =
+ of_property_read_bool(port_node, "dual-lvds-odd-pixels");
+
+ return (even_pixels ? DRM_OF_LVDS_EVEN : 0) |
+ (odd_pixels ? DRM_OF_LVDS_ODD : 0);
+}
+
+static int drm_of_lvds_get_remote_pixels_type(
+ const struct device_node *port_node)
+{
+ struct device_node *endpoint = NULL;
+ int pixels_type = -EPIPE;
+
+ for_each_child_of_node(port_node, endpoint) {
+ struct device_node *remote_port;
+ int current_pt;
+
+ if (!of_node_name_eq(endpoint, "endpoint"))
+ continue;
+
+ remote_port = of_graph_get_remote_port(endpoint);
+ if (!remote_port) {
+ of_node_put(remote_port);
+ return -EPIPE;
+ }
+
+ current_pt = drm_of_lvds_get_port_pixels_type(remote_port);
+ of_node_put(remote_port);
+ if (pixels_type < 0)
+ pixels_type = current_pt;
+
+ /*
+ * Sanity check, ensure that all remote endpoints have the same
+ * pixel type. We may lift this restriction later if we need to
+ * support multiple sinks with different dual-link
+ * configurations by passing the endpoints explicitly to
+ * drm_of_lvds_get_dual_link_pixel_order().
+ */
+ if (!current_pt || pixels_type != current_pt) {
+ of_node_put(remote_port);
+ return -EINVAL;
+ }
+ }
+
+ return pixels_type;
+}
+
+/**
+ * drm_of_lvds_get_dual_link_pixel_order - Get LVDS dual-link pixel order
+ * @port1: First DT port node of the Dual-link LVDS source
+ * @port2: Second DT port node of the Dual-link LVDS source
+ *
+ * An LVDS dual-link connection is made of two links, with even pixels
+ * transitting on one link, and odd pixels on the other link. This function
+ * returns, for two ports of an LVDS dual-link source, which port shall transmit
+ * the even and odd pixels, based on the requirements of the connected sink.
+ *
+ * The pixel order is determined from the dual-lvds-even-pixels and
+ * dual-lvds-odd-pixels properties in the sink's DT port nodes. If those
+ * properties are not present, or if their usage is not valid, this function
+ * returns -EINVAL.
+ *
+ * If either port is not connected, this function returns -EPIPE.
+ *
+ * @port1 and @port2 are typically DT sibling nodes, but may have different
+ * parents when, for instance, two separate LVDS encoders carry the even and odd
+ * pixels.
+ *
+ * Return:
+ * * DRM_LVDS_DUAL_LINK_EVEN_ODD_PIXELS - @port1 carries even pixels and @port2
+ * carries odd pixels
+ * * DRM_LVDS_DUAL_LINK_ODD_EVEN_PIXELS - @port1 carries odd pixels and @port2
+ * carries even pixels
+ * * -EINVAL - @port1 and @port2 are not connected to a dual-link LVDS sink, or
+ * the sink configuration is invalid
+ * * -EPIPE - when @port1 or @port2 are not connected
+ */
+int drm_of_lvds_get_dual_link_pixel_order(const struct device_node *port1,
+ const struct device_node *port2)
+{
+ int remote_p1_pt, remote_p2_pt;
+
+ if (!port1 || !port2)
+ return -EINVAL;
+
+ remote_p1_pt = drm_of_lvds_get_remote_pixels_type(port1);
+ if (remote_p1_pt < 0)
+ return remote_p1_pt;
+
+ remote_p2_pt = drm_of_lvds_get_remote_pixels_type(port2);
+ if (remote_p2_pt < 0)
+ return remote_p2_pt;
+
+ /*
+ * A valid dual-lVDS bus is found when one remote port is marked with
+ * "dual-lvds-even-pixels", and the other remote port is marked with
+ * "dual-lvds-odd-pixels", bail out if the markers are not right.
+ */
+ if (remote_p1_pt + remote_p2_pt != DRM_OF_LVDS_EVEN + DRM_OF_LVDS_ODD)
+ return -EINVAL;
+
+ return remote_p1_pt == DRM_OF_LVDS_EVEN ?
+ DRM_LVDS_DUAL_LINK_EVEN_ODD_PIXELS :
+ DRM_LVDS_DUAL_LINK_ODD_EVEN_PIXELS;
+}
+EXPORT_SYMBOL_GPL(drm_of_lvds_get_dual_link_pixel_order);
@@ -16,6 +16,18 @@ struct drm_panel;
struct drm_bridge;
struct device_node;
+/**
+ * enum drm_lvds_dual_link_pixels - Pixel order of an LVDS dual-link connection
+ * @DRM_LVDS_DUAL_LINK_EVEN_ODD_PIXELS: Even pixels are expected to be generated
+ * from the first port, odd pixels from the second port
+ * @DRM_LVDS_DUAL_LINK_ODD_EVEN_PIXELS: Odd pixels are expected to be generated
+ * from the first port, even pixels from the second port
+ */
+enum drm_lvds_dual_link_pixels {
+ DRM_LVDS_DUAL_LINK_EVEN_ODD_PIXELS = 0,
+ DRM_LVDS_DUAL_LINK_ODD_EVEN_PIXELS = 1,
+};
+
#ifdef CONFIG_OF
uint32_t drm_of_crtc_port_mask(struct drm_device *dev,
struct device_node *port);
@@ -35,6 +47,8 @@ int drm_of_find_panel_or_bridge(const struct device_node *np,
int port, int endpoint,
struct drm_panel **panel,
struct drm_bridge **bridge);
+int drm_of_lvds_get_dual_link_pixel_order(const struct device_node *port1,
+ const struct device_node *port2);
#else
static inline uint32_t drm_of_crtc_port_mask(struct drm_device *dev,
struct device_node *port)
@@ -77,6 +91,12 @@ static inline int drm_of_find_panel_or_bridge(const struct device_node *np,
{
return -EINVAL;
}
+
+int drm_of_lvds_get_dual_link_pixel_order(const struct device_node *port1,
+ const struct device_node *port2)
+{
+ return -EINVAL;
+}
#endif
/*