V4L/DVB (9653): em28xx: improve AC97 handling

AC97 devices provide several input and outputs. However, before this
patch, em28xx device weren't properly allowing the usage of ac97
possible combinations. Also, several input volumes were left untouched,
instead of making sure that the volumes were set on mute state.

This patch improves support for ac97 devices by allowing to use any
inputs, and making sure that unused inputs are set on mute state.

Yet, some work is still needed to select the AC97 output.

Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

1 files changed, 18 insertions, 2 deletions

diff --git a/drivers/media/video/em28xx/em28xx.h b/drivers/media/video/em28xx/em28xx.h
index d965caba63e3..6d04ebf46e7c 100644
--- a/drivers/media/video/em28xx/em28xx.h
+++ b/drivers/media/video/em28xx/em28xx.h
@@ -274,9 +274,25 @@ struct em28xx_audio_mode {
         unsigned int i2s_5rates:1;
 };
 
+/* em28xx has two audio inputs: tuner and line in.
+   However, on most devices, an auxiliary AC97 codec device is used.
+   The AC97 device may have several different inputs and outputs,
+   depending on their model. So, it is possible to use AC97 mixer to
+   address more than two different entries.
+ */
 enum em28xx_amux {
-        EM28XX_AMUX_VIDEO,
-        EM28XX_AMUX_LINE_IN,
+        /* This is the only entry for em28xx tuner input */
+        EM28XX_AMUX_VIDEO,      /* em28xx tuner, AC97 mixer Video */
+
+        EM28XX_AMUX_LINE_IN,    /* AC97 mixer Line In */
+
+        /* Some less-common mixer setups */
+        EM28XX_AMUX_VIDEO2,     /* em28xx Line in, AC97 mixer Video */
+        EM28XX_AMUX_PHONE,
+        EM28XX_AMUX_MIC,
+        EM28XX_AMUX_CD,
+        EM28XX_AMUX_AUX,
+        EM28XX_AMUX_PCM_OUT,
 };
 
 struct em28xx_input {