[PATCH v6 16/26] drm/bridge: increment refcount in of_drm_find_bridge()

[Luca Ceresoli]

of_drm_find_bridge() returns a pointer to a bridge, so it has to get a
reference and the caller will be in charge of putting it.

Callers of of_drm_find_bridge() are:

 1. drm_of_panel_bridge_remove()
 2. of_drm_find_bridge_by_endpoint()
 3. drm_of_find_panel_or_bridge()
 4. various DRM drivers

Add the corresponding drm_bridge_put() call for 1 and propagate
documentation to 2 and 3.

Other callers (4) are to be adapted in following commits.

Signed-off-by: Luca Ceresoli <luca.ceresoli@xxxxxxxxxxx>

---

This patch was added in v6.
---
 drivers/gpu/drm/bridge/panel.c | 3 +++
 drivers/gpu/drm/drm_bridge.c   | 7 +++++++
 include/drm/drm_of.h           | 1 +
 3 files changed, 11 insertions(+)

diff --git a/drivers/gpu/drm/bridge/panel.c b/drivers/gpu/drm/bridge/panel.c
index 1230ae50b2020e7a9306cac83009dd600dd61d26..3c0e22e61c1092de1571d800ac440aad7b5c86bc 100644
--- a/drivers/gpu/drm/bridge/panel.c
+++ b/drivers/gpu/drm/bridge/panel.c
@@ -363,6 +363,9 @@ EXPORT_SYMBOL(of_drm_find_panel);
  * return either the associated struct drm_panel or drm_bridge device. Either
  * @panel or @bridge must not be NULL.
  *
+ * If a bridge is returned in @bridge, the bridge refcount is
+ * incremented. Use drm_bridge_put() when done with the bridge.
+ *
  * This function is deprecated and should not be used in new drivers. Use
  * devm_drm_of_get_bridge() instead.
  *
diff --git a/drivers/gpu/drm/drm_bridge.c b/drivers/gpu/drm/drm_bridge.c
index 497ec06dfcb05ab5dee8ea5e8f1eafb9c2807612..fca860d582f86b35c9172b27be20060de086e38f 100644
--- a/drivers/gpu/drm/drm_bridge.c
+++ b/drivers/gpu/drm/drm_bridge.c
@@ -1396,6 +1396,9 @@ EXPORT_SYMBOL_GPL(drm_bridge_hpd_notify);
  *
  * @np: device node
  *
+ * On return the bridge refcount is incremented (if the bridge is
+ * refcounted). Use drm_bridge_put() when done with the bridge.
+ *
  * RETURNS:
  * drm_bridge control struct on success, NULL on failure
  */
@@ -1407,6 +1410,7 @@ struct drm_bridge *of_drm_find_bridge(struct device_node *np)
 
 	list_for_each_entry(bridge, &bridge_list, list) {
 		if (bridge->of_node == np) {
+			drm_bridge_get(bridge);
 			mutex_unlock(&bridge_lock);
 			return bridge;
 		}
@@ -1427,6 +1431,9 @@ EXPORT_SYMBOL(of_drm_find_bridge);
  * Given a DT node's port and endpoint number, find the connected node and
  * return the associated struct drm_bridge.
  *
+ * On success the returned @bridge refcount is incremented. Use
+ * drm_bridge_put() when done with the bridge.
+ *
  * Returns zero if successful, or one of the standard error codes if it fails.
  */
 static int of_drm_find_bridge_by_endpoint(const struct device_node *np,
diff --git a/include/drm/drm_of.h b/include/drm/drm_of.h
index 7f0256dae3f13de1d4109e9265d66684ef2a08ee..948672c27d2eb3034b2519e0bba0fcb52d5c697b 100644
--- a/include/drm/drm_of.h
+++ b/include/drm/drm_of.h
@@ -172,6 +172,7 @@ static inline int drm_of_panel_bridge_remove(const struct device_node *np,
 
 	bridge = of_drm_find_bridge(remote);
 	drm_panel_bridge_remove(bridge);
+	drm_bridge_put(bridge);
 
 	return 0;
 #else

-- 
2.34.1