[PATCH v6 15/26] drm/bridge: devm_drm_of_get_bridge and drmm_of_get_bridge: automatically put the bridge

Luca Ceresoli
2025-02-06T18:15:19Z

Add a devm/drmm action to these functions so the bridge reference is
dropped automatically when the caller is removed.

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

---

This patch was added in v6.
---
drivers/gpu/drm/drm_bridge.c | 39 +++++++++++++++++++++++++++++++++++++++
1 file changed, 39 insertions(+)

diff --git a/drivers/gpu/drm/drm_bridge.c b/drivers/gpu/drm/drm_bridge.c
index f694b32ca59cb91c32846bc00b43360df41cc1ad..497ec06dfcb05ab5dee8ea5e8f1eafb9c2807612 100644
--- a/drivers/gpu/drm/drm_bridge.c
+++ b/drivers/gpu/drm/drm_bridge.c
@@ -33,6 +33,7 @@
#include <drm/drm_edid.h>
#include <drm/drm_encoder.h>
#include <drm/drm_file.h>
+#include <drm/drm_managed.h>
#include <drm/drm_of.h>
#include <drm/drm_print.h>

@@ -1459,6 +1460,13 @@ static int of_drm_find_bridge_by_endpoint(const struct device_node *np,
return ret;
}

+static void devm_drm_bridge_put_void(void *data)
+{
+ struct drm_bridge *bridge = (struct drm_bridge *)data;
+
+ drm_bridge_put(bridge);
+}
+
/**
* devm_drm_of_get_bridge - Return next bridge in the chain
* @dev: device to tie the bridge lifetime to
@@ -1469,6 +1477,10 @@ static int of_drm_find_bridge_by_endpoint(const struct device_node *np,
* Given a DT node's port and endpoint number, finds the connected node
* and returns the associated bridge if any.
*
+ * The refcount of the returned bridge is incremented, but the caller does
+ * not have to call drm_bridge_put() when done with the bridge. It will be
+ * done by devres when @dev is removed.
+ *
* Returns a pointer to the bridge if successful, or an error pointer
* otherwise.
*/
@@ -1483,6 +1495,10 @@ struct drm_bridge *devm_drm_of_get_bridge(struct device *dev,
if (ret)
return ERR_PTR(ret);

+ ret = devm_add_action_or_reset(dev, devm_drm_bridge_put_void, bridge);
+ if (ret)
+ return ERR_PTR(ret);
+
return bridge;
}
EXPORT_SYMBOL(devm_drm_of_get_bridge);
@@ -1497,6 +1513,10 @@ EXPORT_SYMBOL(devm_drm_of_get_bridge);
* graph link search is not enough, e.g. for drivers that need to support
* panels described only as subnodes.
*
+ * The refcount of the returned bridge is incremented, but the caller does
+ * not have to call drm_bridge_put() when done with the bridge. It will be
+ * done by devres when @dev is removed.
+ *
* RETURNS:
* A pointer to the bridge if successful, or an error pointer otherwise.
*/
@@ -1513,10 +1533,21 @@ struct drm_bridge *devm_drm_of_get_bridge_by_node(struct device *dev,
if (!bridge)
return ERR_PTR(-ENODEV);

+ ret = devm_add_action_or_reset(dev, devm_drm_bridge_put_void, bridge);
+ if (ret)
+ return ERR_PTR(ret);
+
return bridge;
}
EXPORT_SYMBOL(devm_drm_of_get_bridge_by_node);

+static void drmm_bridge_put_void(struct drm_device *drm, void *ptr)
+{
+ struct drm_bridge *bridge = ptr;
+
+ drm_bridge_put(bridge);
+}
+
/**
* drmm_of_get_bridge - Return next bridge in the chain
* @drm: device to tie the bridge lifetime to
@@ -1527,6 +1558,10 @@ EXPORT_SYMBOL(devm_drm_of_get_bridge_by_node);
* Given a DT node's port and endpoint number, finds the connected node
* and returns the associated bridge if any.
*
+ * The refcount of the returned bridge is incremented, but the caller does
+ * not have to call drm_bridge_put() when done with the bridge. It will be
+ * done by drmm when @dev is removed.
+ *
* Returns a drmm managed pointer to the bridge if successful, or an error
* pointer otherwise.
*/
@@ -1541,6 +1576,10 @@ struct drm_bridge *drmm_of_get_bridge(struct drm_device *drm,
if (ret)
return ERR_PTR(ret);

+ ret = drmm_add_action_or_reset(drm, drmm_bridge_put_void, bridge);
+ if (ret)
+ return ERR_PTR(ret);
+
return bridge;
}
EXPORT_SYMBOL(drmm_of_get_bridge);

--
2.34.1