ALSA: pcm: Fix missing return value comments for kernel docs

Each kernel doc comment expects the definition of the return value in
a proper format.  This patch adds or fixes the missing entries for PCM
API.

Link: https://lore.kernel.org/r/20220713104759.4365-3-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>

3 files changed, 14 insertions, 0 deletions

diff --git a/sound/core/pcm.c b/sound/core/pcm.c
index 977d54320a5c..03fc5fa5813e 100644
--- a/sound/core/pcm.c
+++ b/sound/core/pcm.c
@@ -216,6 +216,8 @@ static const char * const snd_pcm_format_names[] = {
 /**
  * snd_pcm_format_name - Return a name string for the given PCM format
  * @format: PCM format
+ *
+ * Return: the format name string
  */
 const char *snd_pcm_format_name(snd_pcm_format_t format)
 {
@@ -1138,6 +1140,8 @@ static int snd_pcm_dev_disconnect(struct snd_device *device)
  * This adds the given notifier to the global list so that the callback is
  * called for each registered PCM devices.  This exists only for PCM OSS
  * emulation, so far.
+ *
+ * Return: zero if successful, or a negative error code
  */
 int snd_pcm_notify(struct snd_pcm_notify *notify, int nfree)
 {
diff --git a/sound/core/pcm_memory.c b/sound/core/pcm_memory.c
index b8296b6eb2c1..7bde7fb64011 100644
--- a/sound/core/pcm_memory.c
+++ b/sound/core/pcm_memory.c
@@ -350,6 +350,8 @@ EXPORT_SYMBOL(snd_pcm_lib_preallocate_pages_for_all);
  * SNDRV_DMA_TYPE_VMALLOC type.
  *
  * Upon successful buffer allocation and setup, the function returns 0.
+ *
+ * Return: zero if successful, or a negative error code
  */
 int snd_pcm_set_managed_buffer(struct snd_pcm_substream *substream, int type,
 				struct device *data, size_t size, size_t max)
@@ -369,6 +371,8 @@ EXPORT_SYMBOL(snd_pcm_set_managed_buffer);
  *
  * Do pre-allocation to all substreams of the given pcm for the specified DMA
  * type and size, and set the managed_buffer_alloc flag to each substream.
+ *
+ * Return: zero if successful, or a negative error code
  */
 int snd_pcm_set_managed_buffer_all(struct snd_pcm *pcm, int type,
 				   struct device *data,
diff --git a/sound/core/pcm_native.c b/sound/core/pcm_native.c
index 4adaee62ef33..aa0453e51595 100644
--- a/sound/core/pcm_native.c
+++ b/sound/core/pcm_native.c
@@ -3412,6 +3412,8 @@ static long snd_pcm_ioctl(struct file *file, unsigned int cmd,
  * The function is provided primarily for OSS layer and USB gadget drivers,
  * and it allows only the limited set of ioctls (hw_params, sw_params,
  * prepare, start, drain, drop, forward).
+ *
+ * Return: zero if successful, or a negative error code
  */
 int snd_pcm_kernel_ioctl(struct snd_pcm_substream *substream,
 			 unsigned int cmd, void *arg)
@@ -3810,6 +3812,8 @@ static const struct vm_operations_struct snd_pcm_vm_ops_data_fault = {
  *
  * This is the default mmap handler for PCM data.  When mmap pcm_ops is NULL,
  * this function is invoked implicitly.
+ *
+ * Return: zero if successful, or a negative error code
  */
 int snd_pcm_lib_default_mmap(struct snd_pcm_substream *substream,
 			     struct vm_area_struct *area)
@@ -3836,6 +3840,8 @@ EXPORT_SYMBOL_GPL(snd_pcm_lib_default_mmap);
  * When your hardware uses the iomapped pages as the hardware buffer and
  * wants to mmap it, pass this function as mmap pcm_ops.  Note that this
  * is supposed to work only on limited architectures.
+ *
+ * Return: zero if successful, or a negative error code
  */
 int snd_pcm_lib_mmap_iomem(struct snd_pcm_substream *substream,
 			   struct vm_area_struct *area)