1 #include <linux/export.h> 2 #include <linux/list.h> 3 #include <linux/of_graph.h> 4 #include <drm/drmP.h> 5 #include <drm/drm_crtc.h> 6 #include <drm/drm_of.h> 7 8 /** 9 * drm_crtc_port_mask - find the mask of a registered CRTC by port OF node 10 * @dev: DRM device 11 * @port: port OF node 12 * 13 * Given a port OF node, return the possible mask of the corresponding 14 * CRTC within a device's list of CRTCs. Returns zero if not found. 15 */ 16 static uint32_t drm_crtc_port_mask(struct drm_device *dev, 17 struct device_node *port) 18 { 19 unsigned int index = 0; 20 struct drm_crtc *tmp; 21 22 drm_for_each_crtc(tmp, dev) { 23 if (tmp->port == port) 24 return 1 << index; 25 26 index++; 27 } 28 29 return 0; 30 } 31 32 /** 33 * drm_of_find_possible_crtcs - find the possible CRTCs for an encoder port 34 * @dev: DRM device 35 * @port: encoder port to scan for endpoints 36 * 37 * Scan all endpoints attached to a port, locate their attached CRTCs, 38 * and generate the DRM mask of CRTCs which may be attached to this 39 * encoder. 40 * 41 * See Documentation/devicetree/bindings/graph.txt for the bindings. 42 */ 43 uint32_t drm_of_find_possible_crtcs(struct drm_device *dev, 44 struct device_node *port) 45 { 46 struct device_node *remote_port, *ep; 47 uint32_t possible_crtcs = 0; 48 49 for_each_endpoint_of_node(port, ep) { 50 remote_port = of_graph_get_remote_port(ep); 51 if (!remote_port) { 52 of_node_put(ep); 53 return 0; 54 } 55 56 possible_crtcs |= drm_crtc_port_mask(dev, remote_port); 57 58 of_node_put(remote_port); 59 } 60 61 return possible_crtcs; 62 } 63 EXPORT_SYMBOL(drm_of_find_possible_crtcs); 64