Allow for checks on a specific USB audio device to see if a requested PCM format is supported. This is needed for support when playback is initiated by the ASoC USB backend path.
Reviewed-by: Pierre-Louis Bossart pierre-louis.bossart@linux.intel.com Signed-off-by: Wesley Cheng quic_wcheng@quicinc.com --- sound/usb/card.c | 32 ++++++++++++++++++++++++++++++++ sound/usb/card.h | 3 +++ 2 files changed, 35 insertions(+)
diff --git a/sound/usb/card.c b/sound/usb/card.c index c6d9d8d548b4..1f9dfcd8f336 100644 --- a/sound/usb/card.c +++ b/sound/usb/card.c @@ -119,6 +119,38 @@ static DEFINE_MUTEX(register_mutex); static struct snd_usb_audio *usb_chip[SNDRV_CARDS]; static struct usb_driver usb_audio_driver;
+/* + * Checks to see if requested audio profile, i.e sample rate, # of + * channels, etc... is supported by the substream associated to the + * USB audio device. + */ +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; + struct snd_usb_substream *subs; + struct snd_usb_stream *as; + + /* + * Register mutex is held when populating and clearing usb_chip + * array. + */ + guard(mutex)(®ister_mutex); + chip = usb_chip[card_idx]; + + if (chip && enable[card_idx]) { + list_for_each_entry(as, &chip->pcm_list, list) { + subs = &as->substream[direction]; + if (snd_usb_find_substream_format(subs, params)) + return as; + } + } + + 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 6ec95b2edf86..4f4f3f39b7fa 100644 --- a/sound/usb/card.h +++ b/sound/usb/card.h @@ -207,4 +207,7 @@ struct snd_usb_stream { struct list_head list; };
+struct snd_usb_stream * +snd_usb_find_suppported_substream(int card_idx, struct snd_pcm_hw_params *params, + int direction); #endif /* __USBAUDIO_CARD_H */