drm: zynqmp_dp: Take dp->lock in zynqmp_dp_hpd_work_func

Add a non-locking version of zynqmp_dp_bridge_detect and use it in
zynqmp_dp_hpd_work_func so we can take the lock explicitly. This will
make it easier to check for hpd_ignore when we add debugfs support.

Signed-off-by: Sean Anderson <sean.anderson@linux.dev>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240809193600.3360015-8-sean.anderson@linux.dev

drivers/gpu/drm/xlnx/zynqmp_dp.c

@@ -1566,14 +1566,13 @@ static int zynqmp_dp_bridge_atomic_check(struct drm_bridge *bridge,
 	return 0;
 }
 
-static enum drm_connector_status zynqmp_dp_bridge_detect(struct drm_bridge *bridge)
+static enum drm_connector_status __zynqmp_dp_bridge_detect(struct zynqmp_dp *dp)
 {
-	struct zynqmp_dp *dp = bridge_to_dp(bridge);
 	struct zynqmp_dp_link_config *link_config = &dp->link_config;
 	u32 state, i;
 	int ret;
 
-	mutex_lock(&dp->lock);
+	lockdep_assert_held(&dp->lock);
 
 	/*
 	 * This is from heuristic. It takes some delay (ex, 100 ~ 500 msec) to
@@ -1602,16 +1601,26 @@ static enum drm_connector_status zynqmp_dp_bridge_detect(struct drm_bridge *brid
 					       dp->num_lanes);
 
 		dp->status = connector_status_connected;
-		mutex_unlock(&dp->lock);
 		return connector_status_connected;
 	}
 
 disconnected:
 	dp->status = connector_status_disconnected;
-	mutex_unlock(&dp->lock);
 	return connector_status_disconnected;
 }
 
+static enum drm_connector_status zynqmp_dp_bridge_detect(struct drm_bridge *bridge)
+{
+	struct zynqmp_dp *dp = bridge_to_dp(bridge);
+	enum drm_connector_status ret;
+
+	mutex_lock(&dp->lock);
+	ret = __zynqmp_dp_bridge_detect(dp);
+	mutex_unlock(&dp->lock);
+
+	return ret;
+}
+
 static const struct drm_edid *zynqmp_dp_bridge_edid_read(struct drm_bridge *bridge,
 							 struct drm_connector *connector)
 {
@@ -1695,7 +1704,10 @@ static void zynqmp_dp_hpd_work_func(struct work_struct *work)
 	struct zynqmp_dp *dp = container_of(work, struct zynqmp_dp, hpd_work);
 	enum drm_connector_status status;
 
-	status = zynqmp_dp_bridge_detect(&dp->bridge);
+	mutex_lock(&dp->lock);
+	status = __zynqmp_dp_bridge_detect(dp);
+	mutex_unlock(&dp->lock);
+
 	drm_bridge_hpd_notify(&dp->bridge, status);
 }