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From: Wesley Cheng <quic_wcheng@quicinc.com>
To: <srinivas.kandagatla@linaro.org>, <mathias.nyman@intel.com>,
        <perex@perex.cz>, <conor+dt@kernel.org>, <corbet@lwn.net>,
        <lgirdwood@gmail.com>, <tiwai@suse.com>, <krzk+dt@kernel.org>,
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        <gregkh@linuxfoundation.org>
CC: <linux-kernel@vger.kernel.org>, <devicetree@vger.kernel.org>,
        <linux-sound@vger.kernel.org>, <linux-usb@vger.kernel.org>,
        <linux-arm-msm@vger.kernel.org>, <linux-doc@vger.kernel.org>,
        <alsa-devel@alsa-project.org>, Wesley Cheng <quic_wcheng@quicinc.com>
Subject: [PATCH v22 14/38] ALSA: usb-audio: Save UAC sample size information
Date: Thu, 23 May 2024 17:10:19 -0700
Message-ID: <20240524001043.10141-15-quic_wcheng@quicinc.com>
In-Reply-To: <20240524001043.10141-1-quic_wcheng@quicinc.com>
References: <20240524001043.10141-1-quic_wcheng@quicinc.com>
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Within the UAC descriptor, there is information describing the size of a
sample (bSubframeSize/bSubslotSize) and the number of relevant bits
(bBitResolution).  Currently, fmt_bits carries only the bit resolution,
however, some offloading entities may also require the overall size of the
sample.  Save this information in a separate parameter, as depending on the
UAC format type, the sample size can not easily be decoded from other
exisiting parameters.

Signed-off-by: Wesley Cheng <quic_wcheng@quicinc.com>
---
 sound/usb/card.h   | 1 +
 sound/usb/format.c | 1 +
 2 files changed, 2 insertions(+)

diff --git a/sound/usb/card.h b/sound/usb/card.h
index 2884912adc96..02e4ea898db5 100644
--- a/sound/usb/card.h
+++ b/sound/usb/card.h
@@ -15,6 +15,7 @@ struct audioformat {
 	unsigned int channels;		/* # channels */
 	unsigned int fmt_type;		/* USB audio format type (1-3) */
 	unsigned int fmt_bits;		/* number of significant bits */
+	unsigned int fmt_sz;		/* overall audio sub frame/slot size */
 	unsigned int frame_size;	/* samples per frame for non-audio */
 	unsigned char iface;		/* interface number */
 	unsigned char altsetting;	/* corresponding alternate setting */
diff --git a/sound/usb/format.c b/sound/usb/format.c
index 3b45d0ee7693..5fde543536a8 100644
--- a/sound/usb/format.c
+++ b/sound/usb/format.c
@@ -80,6 +80,7 @@ static u64 parse_audio_format_i_type(struct snd_usb_audio *chip,
 	}
 
 	fp->fmt_bits = sample_width;
+	fp->fmt_sz = sample_bytes;
 
 	if ((pcm_formats == 0) &&
 	    (format == 0 || format == (1 << UAC_FORMAT_TYPE_I_UNDEFINED))) {