ALSA: usb-audio: Add native DSD support for TEAC 501/503 DAC

This patch adds native DSD support for the following devices.

- TEAC NT-503
- TEAC UD-503
- TEAC UD-501

(1) Add quirks for native DSD support for TEAC devices.
(2) A specific vendor command is needed to switch between PCM/DOP and
    DSD mode, same as Denon/Marantz devices.

Signed-off-by: Nobutaka Okabe <nob77413@gmail.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

1 files changed, 38 insertions, 0 deletions

diff --git a/sound/usb/quirks.c b/sound/usb/quirks.c
index 2782155ae3ce..b3fd2382fdd9 100644
--- a/sound/usb/quirks.c
+++ b/sound/usb/quirks.c
@@ -1165,6 +1165,18 @@ static bool is_marantz_denon_dac(unsigned int id)
         return false;
 }
 
+/* TEAC UD-501/UD-503/NT-503 USB DACs need a vendor cmd to switch
+ * between PCM/DOP and native DSD mode
+ */
+static bool is_teac_50X_dac(unsigned int id)
+{
+        switch (id) {
+        case USB_ID(0x0644, 0x8043): /* TEAC UD-501/UD-503/NT-503 */
+                return true;
+        }
+        return false;
+}
+
 int snd_usb_select_mode_quirk(struct snd_usb_substream *subs,
                               struct audioformat *fmt)
 {
@@ -1192,6 +1204,26 @@ int snd_usb_select_mode_quirk(struct snd_usb_substream *subs,
                         break;
                 }
                 mdelay(20);
+        } else if (is_teac_50X_dac(subs->stream->chip->usb_id)) {
+                /* Vendor mode switch cmd is required. */
+                switch (fmt->altsetting) {
+                case 3: /* DSD mode (DSD_U32) requested */
+                        err = snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0), 0,
+                                              USB_DIR_OUT|USB_TYPE_VENDOR|USB_RECIP_INTERFACE,
+                                              1, 1, NULL, 0);
+                        if (err < 0)
+                                return err;
+                        break;
+
+                case 2: /* PCM or DOP mode (S32) requested */
+                case 1: /* PCM mode (S16) requested */
+                        err = snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0), 0,
+                                              USB_DIR_OUT|USB_TYPE_VENDOR|USB_RECIP_INTERFACE,
+                                              0, 1, NULL, 0);
+                        if (err < 0)
+                                return err;
+                        break;
+                }
         }
         return 0;
 }
@@ -1337,5 +1369,11 @@ u64 snd_usb_interface_dsd_format_quirks(struct snd_usb_audio *chip,
                         return SNDRV_PCM_FMTBIT_DSD_U32_BE;
         }
 
+        /* TEAC devices with USB DAC functionality */
+        if (is_teac_50X_dac(chip->usb_id)) {
+                if (fp->altsetting == 3)
+                        return SNDRV_PCM_FMTBIT_DSD_U32_BE;
+        }
+
         return 0;
 }