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Message-ID: <20241011000650.2585600-24-quic_wcheng@quicinc.com>
Date: Thu, 10 Oct 2024 17:06:08 -0700
From: Wesley Cheng <quic_wcheng@...cinc.com>
To: <srinivas.kandagatla@...aro.org>, <mathias.nyman@...el.com>,
<perex@...ex.cz>, <conor+dt@...nel.org>, <dmitry.torokhov@...il.com>,
<corbet@....net>, <broonie@...nel.org>, <lgirdwood@...il.com>,
<tiwai@...e.com>, <krzk+dt@...nel.org>,
<pierre-louis.bossart@...ux.intel.com>, <Thinh.Nguyen@...opsys.com>,
<bgoswami@...cinc.com>, <robh@...nel.org>,
<gregkh@...uxfoundation.org>
CC: <linux-kernel@...r.kernel.org>, <devicetree@...r.kernel.org>,
<linux-sound@...r.kernel.org>, <linux-input@...r.kernel.org>,
<linux-usb@...r.kernel.org>, <linux-arm-msm@...r.kernel.org>,
<linux-doc@...r.kernel.org>, <alsa-devel@...a-project.org>,
Wesley Cheng
<quic_wcheng@...cinc.com>
Subject: [PATCH v28 12/33] ALSA: usb-audio: Check for support for requested audio format
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@...ux.intel.com>
Signed-off-by: Wesley Cheng <quic_wcheng@...cinc.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 */
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