ALSA: usb-audio: Add a more accurate volume quirk for AudioQuest DragonFly

[pandora-kernel.git] / sound / usb / mixer_quirks.c

diff --git a/sound/usb/mixer_quirks.c b/sound/usb/mixer_quirks.c
index 040d101..21f4d44 100644 (file)
--- a/sound/usb/mixer_quirks.c
+++ b/sound/usb/mixer_quirks.c
@@ -34,6 +34,7 @@
 #include <sound/control.h>
 #include <sound/hwdep.h>
 #include <sound/info.h>
+#include <sound/tlv.h>
 
 #include "usbaudio.h"
 #include "mixer.h"
@@ -682,3 +683,39 @@ void snd_usb_mixer_rc_memory_change(struct usb_mixer_interface *mixer,
        }
 }
 
+static void snd_dragonfly_quirk_db_scale(struct usb_mixer_interface *mixer,
+                                        struct snd_kcontrol *kctl)
+{
+       /* Approximation using 10 ranges based on output measurement on hw v1.2.
+        * This seems close to the cubic mapping e.g. alsamixer uses. */
+       static const DECLARE_TLV_DB_RANGE(scale,
+                0,  1, TLV_DB_MINMAX_ITEM(-5300, -4970),
+                2,  5, TLV_DB_MINMAX_ITEM(-4710, -4160),
+                6,  7, TLV_DB_MINMAX_ITEM(-3884, -3710),
+                8, 14, TLV_DB_MINMAX_ITEM(-3443, -2560),
+               15, 16, TLV_DB_MINMAX_ITEM(-2475, -2324),
+               17, 19, TLV_DB_MINMAX_ITEM(-2228, -2031),
+               20, 26, TLV_DB_MINMAX_ITEM(-1910, -1393),
+               27, 31, TLV_DB_MINMAX_ITEM(-1322, -1032),
+               32, 40, TLV_DB_MINMAX_ITEM(-968, -490),
+               41, 50, TLV_DB_MINMAX_ITEM(-441, 0),
+       );
+
+       dev_info(&mixer->chip->dev->dev, "applying DragonFly dB scale quirk\n");
+       kctl->tlv.p = scale;
+       kctl->vd[0].access |= SNDRV_CTL_ELEM_ACCESS_TLV_READ;
+       kctl->vd[0].access &= ~SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK;
+}
+
+void snd_usb_mixer_fu_apply_quirk(struct usb_mixer_interface *mixer,
+                                 struct usb_mixer_elem_info *cval, int unitid,
+                                 struct snd_kcontrol *kctl)
+{
+       switch (mixer->chip->usb_id) {
+       case USB_ID(0x21b4, 0x0081): /* AudioQuest DragonFly */
+               if (unitid == 7 && cval->min == 0 && cval->max == 50)
+                       snd_dragonfly_quirk_db_scale(mixer, kctl);
+               break;
+       }
+}
+