drivers/gpu/drm/drm_of.c

   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         list_for_each_entry(tmp, &dev->mode_config.crtc_list, head) {
  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 = NULL;
  47         uint32_t possible_crtcs = 0;
  48
  49         do {
  50                 ep = of_graph_get_next_endpoint(port, ep);
  51                 if (!ep)
  52                         break;
  53
  54                 remote_port = of_graph_get_remote_port(ep);
  55                 if (!remote_port) {
  56                         of_node_put(ep);
  57                         return 0;
  58                 }
  59
  60                 possible_crtcs |= drm_crtc_port_mask(dev, remote_port);
  61
  62                 of_node_put(remote_port);
  63         } while (1);
  64
  65         return possible_crtcs;
  66 }
  67 EXPORT_SYMBOL(drm_of_find_possible_crtcs);