drm/bridge: add ->edid_read hook and drm_bridge_edid_read()

From Jani Nikula
2b6aaf7b193be2bfa4e1af90c0d96e78a80aef69 in linux-6.6.y/6.6.24
d807ad80d811ba0c22adfd871e2a46491f80d6e2 in mainline linux

diff --git a/sys/dev/pci/drm/drm_bridge.c b/sys/dev/pci/drm/drm_bridge.c
index 0ad7e77..ce49062 100644 (file)
--- a/sys/dev/pci/drm/drm_bridge.c
+++ b/sys/dev/pci/drm/drm_bridge.c
@@ -27,8 +27,9 @@
 #include <linux/mutex.h>
 
 #include <drm/drm_atomic_state_helper.h>
-#include <drm/drm_debugfs.h>
 #include <drm/drm_bridge.h>
+#include <drm/drm_debugfs.h>
+#include <drm/drm_edid.h>
 #include <drm/drm_encoder.h>
 #include <drm/drm_file.h>
 #include <drm/drm_of.h>
@@ -1213,6 +1214,47 @@ int drm_bridge_get_modes(struct drm_bridge *bridge,
 }
 EXPORT_SYMBOL_GPL(drm_bridge_get_modes);
 
+/**
+ * drm_bridge_edid_read - read the EDID data of the connected display
+ * @bridge: bridge control structure
+ * @connector: the connector to read EDID for
+ *
+ * If the bridge supports output EDID retrieval, as reported by the
+ * DRM_BRIDGE_OP_EDID bridge ops flag, call &drm_bridge_funcs.edid_read to get
+ * the EDID and return it. Otherwise return NULL.
+ *
+ * If &drm_bridge_funcs.edid_read is not set, fall back to using
+ * drm_bridge_get_edid() and wrapping it in struct drm_edid.
+ *
+ * RETURNS:
+ * The retrieved EDID on success, or NULL otherwise.
+ */
+const struct drm_edid *drm_bridge_edid_read(struct drm_bridge *bridge,
+                                           struct drm_connector *connector)
+{
+       if (!(bridge->ops & DRM_BRIDGE_OP_EDID))
+               return NULL;
+
+       /* Transitional: Fall back to ->get_edid. */
+       if (!bridge->funcs->edid_read) {
+               const struct drm_edid *drm_edid;
+               struct edid *edid;
+
+               edid = drm_bridge_get_edid(bridge, connector);
+               if (!edid)
+                       return NULL;
+
+               drm_edid = drm_edid_alloc(edid, (edid->extensions + 1) * EDID_LENGTH);
+
+               kfree(edid);
+
+               return drm_edid;
+       }
+
+       return bridge->funcs->edid_read(bridge, connector);
+}
+EXPORT_SYMBOL_GPL(drm_bridge_edid_read);
+
 /**
  * drm_bridge_get_edid - get the EDID data of the connected display
  * @bridge: bridge control structure
@@ -1222,6 +1264,8 @@ EXPORT_SYMBOL_GPL(drm_bridge_get_modes);
  * DRM_BRIDGE_OP_EDID bridge ops flag, call &drm_bridge_funcs.get_edid to
  * get the EDID and return it. Otherwise return NULL.
  *
+ * Deprecated. Prefer using drm_bridge_edid_read().
+ *
  * RETURNS:
  * The retrieved EDID on success, or NULL otherwise.
  */

diff --git a/sys/dev/pci/drm/include/drm/drm_bridge.h b/sys/dev/pci/drm/include/drm/drm_bridge.h
index 1482d6d..a696bb9 100644 (file)
--- a/sys/dev/pci/drm/include/drm/drm_bridge.h
+++ b/sys/dev/pci/drm/include/drm/drm_bridge.h
@@ -555,6 +555,37 @@ struct drm_bridge_funcs {
        int (*get_modes)(struct drm_bridge *bridge,
                         struct drm_connector *connector);
 
+       /**
+        * @edid_read:
+        *
+        * Read the EDID data of the connected display.
+        *
+        * The @edid_read callback is the preferred way of reporting mode
+        * information for a display connected to the bridge output. Bridges
+        * that support reading EDID shall implement this callback and leave
+        * the @get_modes callback unimplemented.
+        *
+        * The caller of this operation shall first verify the output
+        * connection status and refrain from reading EDID from a disconnected
+        * output.
+        *
+        * This callback is optional. Bridges that implement it shall set the
+        * DRM_BRIDGE_OP_EDID flag in their &drm_bridge->ops.
+        *
+        * The connector parameter shall be used for the sole purpose of EDID
+        * retrieval, and shall not be stored internally by bridge drivers for
+        * future usage.
+        *
+        * RETURNS:
+        *
+        * An edid structure newly allocated with drm_edid_alloc() or returned
+        * from drm_edid_read() family of functions on success, or NULL
+        * otherwise. The caller is responsible for freeing the returned edid
+        * structure with drm_edid_free().
+        */
+       const struct drm_edid *(*edid_read)(struct drm_bridge *bridge,
+                                           struct drm_connector *connector);
+
        /**
         * @get_edid:
         *
@@ -888,6 +919,8 @@ drm_atomic_helper_bridge_propagate_bus_fmt(struct drm_bridge *bridge,
 enum drm_connector_status drm_bridge_detect(struct drm_bridge *bridge);
 int drm_bridge_get_modes(struct drm_bridge *bridge,
                         struct drm_connector *connector);
+const struct drm_edid *drm_bridge_edid_read(struct drm_bridge *bridge,
+                                           struct drm_connector *connector);
 struct edid *drm_bridge_get_edid(struct drm_bridge *bridge,
                                 struct drm_connector *connector);
 void drm_bridge_hpd_enable(struct drm_bridge *bridge,