diff --git a/drivers/gpu/drm/drm_of.c b/drivers/gpu/drm/drm_of.c index 0ca58803ba46..b50b44e76279 100644 --- a/drivers/gpu/drm/drm_of.c +++ b/drivers/gpu/drm/drm_of.c @@ -274,3 +274,119 @@ 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); diff --git a/include/drm/drm_of.h b/include/drm/drm_of.h index ead34ab5ca4e..8ec7ca6d2369 100644 --- a/include/drm/drm_of.h +++ b/include/drm/drm_of.h @@ -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 /*