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Message-ID: <20240203023645.31105-33-quic_wcheng@quicinc.com>
Date: Fri, 2 Feb 2024 18:36:24 -0800
From: Wesley Cheng <quic_wcheng@...cinc.com>
To: <srinivas.kandagatla@...aro.org>, <mathias.nyman@...el.com>,
<perex@...ex.cz>, <conor+dt@...nel.org>, <corbet@....net>,
<lgirdwood@...il.com>, <andersson@...nel.org>,
<krzysztof.kozlowski+dt@...aro.org>, <gregkh@...uxfoundation.org>,
<Thinh.Nguyen@...opsys.com>, <broonie@...nel.org>,
<bgoswami@...cinc.com>, <tiwai@...e.com>, <robh+dt@...nel.org>,
<konrad.dybcio@...aro.org>
CC: <linux-kernel@...r.kernel.org>, <devicetree@...r.kernel.org>,
<linux-sound@...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 v13 32/53] 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.
Signed-off-by: Wesley Cheng <quic_wcheng@...cinc.com>
---
sound/usb/card.c | 40 ++++++++++++++++++++++++++++++++++++++++
sound/usb/card.h | 11 +++++++++++
2 files changed, 51 insertions(+)
diff --git a/sound/usb/card.c b/sound/usb/card.c
index c0b312e264bf..11b827b7a2a5 100644
--- a/sound/usb/card.c
+++ b/sound/usb/card.c
@@ -162,6 +162,46 @@ int snd_usb_unregister_platform_ops(void)
}
EXPORT_SYMBOL_GPL(snd_usb_unregister_platform_ops);
+/*
+ * 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;
+ const struct audioformat *fmt;
+
+ /*
+ * Register mutex is held when populating and clearing usb_chip
+ * array.
+ */
+ mutex_lock(®ister_mutex);
+ chip = usb_chip[card_idx];
+ if (!chip) {
+ mutex_unlock(®ister_mutex);
+ return NULL;
+ }
+
+ if (enable[card_idx]) {
+ list_for_each_entry(as, &chip->pcm_list, list) {
+ subs = &as->substream[direction];
+ fmt = snd_usb_find_substream_format(subs, params);
+ if (fmt) {
+ mutex_unlock(®ister_mutex);
+ return as;
+ }
+ }
+ }
+ mutex_unlock(®ister_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 02e4ea898db5..ed4a664e24e5 100644
--- a/sound/usb/card.h
+++ b/sound/usb/card.h
@@ -217,4 +217,15 @@ struct snd_usb_platform_ops {
int snd_usb_register_platform_ops(struct snd_usb_platform_ops *ops);
int snd_usb_unregister_platform_ops(void);
+
+#if IS_ENABLED(CONFIG_SND_USB_AUDIO)
+struct snd_usb_stream *snd_usb_find_suppported_substream(int card_idx,
+ struct snd_pcm_hw_params *params, int direction);
+#else
+static 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 */
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