[PATCH v7 01/11] drm/bridge: add devm_drm_bridge_alloc()
From: Luca Ceresoli
Date: Fri Mar 14 2025 - 06:32:00 EST
Add a macro to allocate and initialize a DRM bridge embedded within a
private driver struct.
Compared to current practice, which is based on [devm_]kzalloc() allocation
followed by open-coded initialization of fields, this allows to have a
common and explicit API to allocate and initialize DRM bridges.
Besides being useful to consolidate bridge driver code, this is a
fundamental step in preparation for adding dynamic lifetime to bridges
based on refcount.
Signed-off-by: Luca Ceresoli <luca.ceresoli@xxxxxxxxxxx>
---
Changes in v7:
- in v6 this was part of "drm/bridge: add support for refcounted DRM
bridges", now split to a separate patch
---
drivers/gpu/drm/drm_bridge.c | 22 ++++++++++++++++++++++
include/drm/drm_bridge.h | 17 +++++++++++++++++
2 files changed, 39 insertions(+)
diff --git a/drivers/gpu/drm/drm_bridge.c b/drivers/gpu/drm/drm_bridge.c
index ea9525ec16b5272d12a21a66913ada38e74e80bc..96df717b2caeb41d45346ded576eaeb2806fd051 100644
--- a/drivers/gpu/drm/drm_bridge.c
+++ b/drivers/gpu/drm/drm_bridge.c
@@ -199,6 +199,28 @@
static DEFINE_MUTEX(bridge_lock);
static LIST_HEAD(bridge_list);
+void *__devm_drm_bridge_alloc(struct device *dev, size_t size, size_t offset,
+ const struct drm_bridge_funcs *funcs)
+{
+ void *container;
+ struct drm_bridge *bridge;
+
+ if (!funcs) {
+ dev_warn(dev, "Missing funcs pointer\n");
+ return ERR_PTR(-EINVAL);
+ }
+
+ container = devm_kzalloc(dev, size, GFP_KERNEL);
+ if (!container)
+ return ERR_PTR(-ENOMEM);
+
+ bridge = container + offset;
+ bridge->funcs = funcs;
+
+ return container;
+}
+EXPORT_SYMBOL(__devm_drm_bridge_alloc);
+
/**
* drm_bridge_add - add the given bridge to the global bridge list
*
diff --git a/include/drm/drm_bridge.h b/include/drm/drm_bridge.h
index b0d86a685a41e3172e0aa15d1c9a5ae8e959255a..dae463b30542d586a595b67f7bdf5a5e898e9572 100644
--- a/include/drm/drm_bridge.h
+++ b/include/drm/drm_bridge.h
@@ -941,6 +941,23 @@ drm_priv_to_bridge(struct drm_private_obj *priv)
return container_of(priv, struct drm_bridge, base);
}
+void *__devm_drm_bridge_alloc(struct device *dev, size_t size, size_t offset,
+ const struct drm_bridge_funcs *funcs);
+
+/**
+ * devm_drm_bridge_alloc - Allocate and initialize a bridge
+ * @dev: struct device of the bridge device
+ * @type: the type of the struct which contains struct &drm_bridge
+ * @member: the name of the &drm_bridge within @type
+ * @funcs: callbacks for this bridge
+ *
+ * Returns:
+ * Pointer to new bridge, or ERR_PTR on failure.
+ */
+#define devm_drm_bridge_alloc(dev, type, member, funcs) \
+ ((type *)__devm_drm_bridge_alloc(dev, sizeof(type), \
+ offsetof(type, member), funcs))
+
void drm_bridge_add(struct drm_bridge *bridge);
int devm_drm_bridge_add(struct device *dev, struct drm_bridge *bridge);
void drm_bridge_remove(struct drm_bridge *bridge);
--
2.48.1