[PATCH v2 1/2] ALSA: usb-audio: Add DJM450 to Pioneer format quirk

[Olivia Mackintosh <livvy@base.nu>]

Like the DJM-750, ensure that the format control message is passed to
the device when opening a stream. It seems as though fmt->sync_ep is not
always set when this function is called hence the passing of the value
at the call site. If this can be fixed, fmt->sync_up should be used as
the wvalue.

There doesn't seem to be a "cpu_to_le24" type function defined hence for
the open code but I did see a similar thing done in Bluez lib. Perhaps
we can get these definitions defined in byteorder.h. See hci_cpu_to_le24
in include/net/bluetooth/hci.h:2543 for similar usage.

Signed-off-by: Olivia Mackintosh <livvy@base.nu>
---
 sound/usb/quirks.c | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/sound/usb/quirks.c b/sound/usb/quirks.c
index e196e364cef1..9ba4682ebc48 100644
--- a/sound/usb/quirks.c
+++ b/sound/usb/quirks.c
@@ -1470,6 +1470,23 @@ static void set_format_emu_quirk(struct snd_usb_substream *subs,
 	subs->pkt_offset_adj = (emu_samplerate_id >= EMU_QUIRK_SR_176400HZ) ? 4 : 0;
 }
 
+static int pioneer_djm_set_format_quirk(struct snd_usb_substream *subs,
+					u16 windex)
+{
+	unsigned int cur_rate = subs->data_endpoint->cur_rate;
+	u8 sr[3];
+	// Convert to little endian
+	sr[0] = cur_rate & 0xff;
+	sr[1] = (cur_rate >> 8) & 0xff;
+	sr[2] = (cur_rate >> 16) & 0xff;
+	usb_set_interface(subs->dev, 0, 1);
+	// we should derive windex from fmt-sync_ep but it's not set
+	snd_usb_ctl_msg(subs->stream->chip->dev,
+		usb_rcvctrlpipe(subs->stream->chip->dev, 0),
+		0x01, 0x22, 0x0100, windex, &sr, 0x0003);
+	return 0;
+}
+
 void snd_usb_set_format_quirk(struct snd_usb_substream *subs,
 			      const struct audioformat *fmt)
 {
@@ -1483,6 +1500,9 @@ void snd_usb_set_format_quirk(struct snd_usb_substream *subs,
 	case USB_ID(0x534d, 0x2109): /* MacroSilicon MS2109 */
 		subs->stream_offset_adj = 2;
 		break;
+	case USB_ID(0x2b73, 0x0013): /* Pioneer DJM-450 */
+		pioneer_djm_set_format_quirk(subs, 0x0082);
+		break;
 	}
 }
 
-- 
2.30.0