drm/bridge: megachips: add get_edid bridge operation

To prepare for a chained bridge setup add support for the
get_edid bridge operation.
There is no need for a copy of the edid - so drop
the pointer to the copy.

v2:
  - Fix so we do not leak memory (Laurent)
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: Peter Senna Tschudin <peter.senna@gmail.com>
Cc: Martin Donnelly <martin.donnelly@ge.com>
Cc: Martyn Welch <martyn.welch@collabora.co.uk>
Cc: Andrzej Hajda <a.hajda@samsung.com>
Cc: Neil Armstrong <narmstrong@baylibre.com>
Cc: Laurent Pinchart <Laurent.pinchart@ideasonboard.com>
Cc: Jonas Karlman <jonas@kwiboo.se>
Cc: Jernej Skrabec <jernej.skrabec@siol.net>
Link: https://patchwork.freedesktop.org/patch/msgid/20200726203324.3722593-13-sam@ravnborg.org

drivers/gpu/drm/bridge/megachips-stdpxxxx-ge-b850v3-fw.c

@@ -61,7 +61,6 @@ struct ge_b850v3_lvds {
 	struct drm_bridge bridge;
 	struct i2c_client *stdp4028_i2c;
 	struct i2c_client *stdp2690_i2c;
-	struct edid *edid;
 };
 
 static struct ge_b850v3_lvds *ge_b850v3_lvds_ptr;
@@ -131,22 +130,26 @@ static u8 *stdp2690_get_edid(struct i2c_client *client)
 	return NULL;
 }
 
-static int ge_b850v3_lvds_get_modes(struct drm_connector *connector)
+static struct edid *ge_b850v3_lvds_get_edid(struct drm_bridge *bridge,
+					    struct drm_connector *connector)
 {
 	struct i2c_client *client;
-	int num_modes = 0;
 
 	client = ge_b850v3_lvds_ptr->stdp2690_i2c;
 
-	kfree(ge_b850v3_lvds_ptr->edid);
-	ge_b850v3_lvds_ptr->edid = (struct edid *)stdp2690_get_edid(client);
+	return (struct edid *)stdp2690_get_edid(client);
+}
 
-	if (ge_b850v3_lvds_ptr->edid) {
-		drm_connector_update_edid_property(connector,
-						      ge_b850v3_lvds_ptr->edid);
-		num_modes = drm_add_edid_modes(connector,
-					       ge_b850v3_lvds_ptr->edid);
-	}
+static int ge_b850v3_lvds_get_modes(struct drm_connector *connector)
+{
+	struct edid *edid;
+	int num_modes;
+
+	edid = ge_b850v3_lvds_get_edid(&ge_b850v3_lvds_ptr->bridge, connector);
+
+	drm_connector_update_edid_property(connector, edid);
+	num_modes = drm_add_edid_modes(connector, edid);
+	kfree(edid);
 
 	return num_modes;
 }
@@ -269,6 +272,7 @@ static int ge_b850v3_lvds_attach(struct drm_bridge *bridge,
 static const struct drm_bridge_funcs ge_b850v3_lvds_funcs = {
 	.attach = ge_b850v3_lvds_attach,
 	.detect = ge_b850v3_lvds_bridge_detect,
+	.get_edid = ge_b850v3_lvds_get_edid,
 };
 
 static int ge_b850v3_lvds_init(struct device *dev)
@@ -304,8 +308,6 @@ static void ge_b850v3_lvds_remove(void)
 
 	drm_bridge_remove(&ge_b850v3_lvds_ptr->bridge);
 
-	kfree(ge_b850v3_lvds_ptr->edid);
-
 	ge_b850v3_lvds_ptr = NULL;
 out:
 	mutex_unlock(&ge_b850v3_lvds_dev_mutex);
@@ -323,7 +325,8 @@ static int stdp4028_ge_b850v3_fw_probe(struct i2c_client *stdp4028_i2c,
 
 	/* drm bridge initialization */
 	ge_b850v3_lvds_ptr->bridge.funcs = &ge_b850v3_lvds_funcs;
-	ge_b850v3_lvds_ptr->bridge.ops = DRM_BRIDGE_OP_DETECT;
+	ge_b850v3_lvds_ptr->bridge.ops = DRM_BRIDGE_OP_DETECT |
+					 DRM_BRIDGE_OP_EDID;
 	ge_b850v3_lvds_ptr->bridge.of_node = dev->of_node;
 	drm_bridge_add(&ge_b850v3_lvds_ptr->bridge);