Allow for checks on a specific USB audio device to see if a requested PCM
format is supported. This is needed for support for when playback is
initiated by the ASoC USB backend path.
Signed-off-by: Wesley Cheng <quic_wcheng@xxxxxxxxxxx>
---
sound/usb/card.c | 28 ++++++++++++++++++++++++++++
sound/usb/card.h | 8 ++++++++
2 files changed, 36 insertions(+)
diff --git a/sound/usb/card.c b/sound/usb/card.c
index 59be5f543315..be06d19ee935 100644
--- a/sound/usb/card.c
+++ b/sound/usb/card.c
@@ -136,6 +136,34 @@ int snd_usb_unregister_platform_ops(void)
}
EXPORT_SYMBOL_GPL(snd_usb_unregister_platform_ops);
+struct snd_usb_stream *snd_usb_find_suppported_substream(int card_idx,
+ struct snd_pcm_hw_params *params, int direction)
+{
+ struct snd_usb_audio *chip = usb_chip[card_idx];
+ struct snd_usb_substream *subs = NULL;
+ struct snd_usb_stream *as;
+ const struct audioformat *fmt;
+
+ if (!chip)
+ return NULL;
+
+ mutex_lock(&chip->mutex);
+ if (enable[card_idx]) {
+ list_for_each_entry(as, &chip->pcm_list, list) {
+ subs = &as->substream[direction];
+ fmt = find_substream_format(subs, params);
+ if (fmt) {
+ mutex_unlock(&chip->mutex);
+ return as;
+ }
+ }
+ }
+ mutex_unlock(&chip->mutex);
+
+ return NULL;
+}
+EXPORT_SYMBOL_GPL(snd_usb_find_suppported_substream);
+
/*
* disconnect streams
* called from usb_audio_disconnect()
diff --git a/sound/usb/card.h b/sound/usb/card.h
index 2249c411c3a1..410a4ffad98e 100644
--- a/sound/usb/card.h
+++ b/sound/usb/card.h
@@ -215,6 +215,8 @@ struct snd_usb_platform_ops {
#if IS_ENABLED(CONFIG_SND_USB_AUDIO)
int snd_usb_register_platform_ops(struct snd_usb_platform_ops *ops);
int snd_usb_unregister_platform_ops(void);
+struct snd_usb_stream *snd_usb_find_suppported_substream(int card_idx,
+ struct snd_pcm_hw_params *params, int direction);
#else
int snd_usb_register_platform_ops(struct snd_usb_platform_ops *ops)
{
@@ -225,5 +227,11 @@ int snd_usb_unregister_platform_ops(void)
{
return -EOPNOTSUPP;
}
+
+struct snd_usb_stream *snd_usb_find_suppported_substream(int card_idx,
+ struct snd_pcm_hw_params *params, int direction)
+{
+ return NULL;
+}
#endif /* IS_ENABLED(CONFIG_SND_USB_AUDIO) */
#endif /* __USBAUDIO_CARD_H */
