of: reserved_mem: Introduce devres-managed initialization function

Introduce devres-based helper for of_reserved_mem_device_init()
to help fight dangling references and ever so slightly reduce the
number of boilerplate deinitialization calls.

Signed-off-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
Signed-off-by: Mukesh Ojha <mukesh.ojha@oss.qualcomm.com>
Link: https://patch.msgid.link/20260730073214.1146432-1-mukesh.ojha@oss.qualcomm.com
Signed-off-by: Rob Herring (Arm) <robh@kernel.org>

2 files changed, 51 insertions, 0 deletions

diff --git a/drivers/of/of_reserved_mem.c b/drivers/of/of_reserved_mem.c
index 9ce55bfd7e2a..5f441a684567 100644
--- a/drivers/of/of_reserved_mem.c
+++ b/drivers/of/of_reserved_mem.c
@@ -788,6 +788,50 @@ void of_reserved_mem_device_release(struct device *dev)
 }
 EXPORT_SYMBOL_GPL(of_reserved_mem_device_release);
 
+static void devm_of_reserved_mem_device_release(struct device *dev, void *res)
+{
+	of_reserved_mem_device_release(*(struct device **)res);
+}
+
+static int devm_of_reserved_mem_device_init_by_idx(struct device *dev,
+						   struct device_node *np, int idx)
+{
+	struct device **ptr;
+	int ret;
+
+	ptr = devres_alloc(devm_of_reserved_mem_device_release, sizeof(*ptr),
+			   GFP_KERNEL);
+	if (!ptr)
+		return -ENOMEM;
+
+	ret = of_reserved_mem_device_init_by_idx(dev, np, idx);
+	if (ret) {
+		devres_free(ptr);
+		return ret;
+	}
+
+	*ptr = dev;
+	devres_add(dev, ptr);
+
+	return 0;
+}
+
+/**
+ * devm_of_reserved_mem_device_init() - Resource managed of_reserved_mem_device_init()
+ * @dev: Pointer to the device to configure
+ *
+ * This is a resource managed version of of_reserved_mem_device_init().
+ * The reserved memory region will be released automatically when the device
+ * is unbound.
+ *
+ * Returns: Negative errno on failure or zero on success.
+ */
+int devm_of_reserved_mem_device_init(struct device *dev)
+{
+	return devm_of_reserved_mem_device_init_by_idx(dev, dev->of_node, 0);
+}
+EXPORT_SYMBOL_GPL(devm_of_reserved_mem_device_init);
+
 /**
  * of_reserved_mem_lookup() - acquire reserved_mem from a device node
  * @np:		node pointer of the desired reserved-memory region
diff --git a/include/linux/of_reserved_mem.h b/include/linux/of_reserved_mem.h
index e8b20b29fa68..49da515859f2 100644
--- a/include/linux/of_reserved_mem.h
+++ b/include/linux/of_reserved_mem.h
@@ -40,6 +40,8 @@ int of_reserved_mem_device_init_by_name(struct device *dev,
 					const char *name);
 void of_reserved_mem_device_release(struct device *dev);
 
+int devm_of_reserved_mem_device_init(struct device *dev);
+
 struct reserved_mem *of_reserved_mem_lookup(struct device_node *np);
 int of_reserved_mem_region_to_resource(const struct device_node *np,
 				       unsigned int idx, struct resource *res);
@@ -68,6 +70,11 @@ static inline int of_reserved_mem_device_init_by_name(struct device *dev,
 
 static inline void of_reserved_mem_device_release(struct device *pdev) { }
 
+static inline int devm_of_reserved_mem_device_init(struct device *dev)
+{
+	return -EOPNOTSUPP;
+}
+
 static inline struct reserved_mem *of_reserved_mem_lookup(struct device_node *np)
 {
 	return NULL;