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.
Signed-off-by: Wesley Cheng quic_wcheng@quicinc.com --- sound/usb/card.c | 31 +++++++++++++++++++++++++++++++ sound/usb/card.h | 2 ++ 2 files changed, 33 insertions(+)
diff --git a/sound/usb/card.c b/sound/usb/card.c index 70b7f22ff495..8c22f6bfdef2 100644 --- a/sound/usb/card.c +++ b/sound/usb/card.c @@ -176,6 +176,37 @@ void snd_usb_rediscover_devices(void) } EXPORT_SYMBOL_GPL(snd_usb_rediscover_devices);
+/* + * 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 f0794aa06cd7..99d6a784eacf 100644 --- a/sound/usb/card.h +++ b/sound/usb/card.h @@ -220,4 +220,6 @@ int snd_usb_register_platform_ops(struct snd_usb_platform_ops *ops); int snd_usb_unregister_platform_ops(void);
void snd_usb_rediscover_devices(void); +struct snd_usb_stream *snd_usb_find_suppported_substream(int card_idx, + struct snd_pcm_hw_params *params, int direction); #endif /* __USBAUDIO_CARD_H */