[ALSA] AD1888 mixer controls for DC mode

This patch adds two mixer controls. The V_REFOUT enable is a
documented register that couples the microphone input lines
to the V_REFOUT DC source. The High Pass Filter enable in the
AC97_AD_TEST2 (0x5c) is an undocumented register provided by
Miller Puckette via Analog Devices that enables the AD codec
to apply a high pass filter to the input.

Signed-off-by: Jaya Kumar <jayakumar.alsa@gmail.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jaroslav Kysela <perex@suse.cz>

1 files changed, 1 insertions, 0 deletions

diff --git a/include/sound/ac97_codec.h b/include/sound/ac97_codec.h
index 446afc3ea27f..758f8bf133c7 100644
--- a/include/sound/ac97_codec.h
+++ b/include/sound/ac97_codec.h
@@ -265,6 +265,7 @@
 
 /* specific - Analog Devices */
 #define AC97_AD_TEST            0x5a    /* test register */
+#define AC97_AD_TEST2           0x5c    /* undocumented test register 2 */
 #define AC97_AD_CODEC_CFG       0x70    /* codec configuration */
 #define AC97_AD_JACK_SPDIF      0x72    /* Jack Sense & S/PDIF */
 #define AC97_AD_SERIAL_CFG      0x74    /* Serial Configuration */