nvmem: change the signature of nvmem_unregister()

We switched the nvmem framework to using kref instead of manually
checking the current number of users in nvmem_unregister() so this
function can no longer fail. We also converted all remaining users
that still checked the return value of nvmem_unregister() to using
devm_nvmem_register(). Make the routine return void.
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/nvmem/core.c

@@ -553,20 +553,16 @@ static void nvmem_device_release(struct kref *kref)
  * nvmem_unregister() - Unregister previously registered nvmem device
  *
  * @nvmem: Pointer to previously registered nvmem device.
- *
- * Return: Will be an negative on error or a zero on success.
  */
-int nvmem_unregister(struct nvmem_device *nvmem)
+void nvmem_unregister(struct nvmem_device *nvmem)
 {
 	kref_put(&nvmem->refcnt, nvmem_device_release);
-
-	return 0;
 }
 EXPORT_SYMBOL_GPL(nvmem_unregister);
 
 static void devm_nvmem_release(struct device *dev, void *res)
 {
-	WARN_ON(nvmem_unregister(*(struct nvmem_device **)res));
+	nvmem_unregister(*(struct nvmem_device **)res);
 }
 
 /**

include/linux/nvmem-provider.h

@@ -70,7 +70,7 @@ struct nvmem_config {
 #if IS_ENABLED(CONFIG_NVMEM)
 
 struct nvmem_device *nvmem_register(const struct nvmem_config *cfg);
-int nvmem_unregister(struct nvmem_device *nvmem);
+void nvmem_unregister(struct nvmem_device *nvmem);
 
 struct nvmem_device *devm_nvmem_register(struct device *dev,
 					 const struct nvmem_config *cfg);
@@ -87,10 +87,7 @@ static inline struct nvmem_device *nvmem_register(const struct nvmem_config *c)
 	return ERR_PTR(-ENOSYS);
 }
 
-static inline int nvmem_unregister(struct nvmem_device *nvmem)
-{
-	return -ENOSYS;
-}
+static inline void nvmem_unregister(struct nvmem_device *nvmem) {}
 
 static inline struct nvmem_device *
 devm_nvmem_register(struct device *dev, const struct nvmem_config *c)
@@ -101,7 +98,7 @@ devm_nvmem_register(struct device *dev, const struct nvmem_config *c)
 static inline int
 devm_nvmem_unregister(struct device *dev, struct nvmem_device *nvmem)
 {
-	return nvmem_unregister(nvmem);
+	return -ENOSYS;
 
 }