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@quicinc.com --- 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 e5d5c0f04c85..e51461ac33cd 100644 --- a/sound/usb/card.c +++ b/sound/usb/card.c @@ -142,6 +142,34 @@ 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 94c3ae7bb4a5..4535b48edd1b 100644 --- a/sound/usb/card.h +++ b/sound/usb/card.h @@ -216,6 +216,8 @@ 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) { @@ -226,5 +228,11 @@ 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 */