V4L/DVB (3584): Implement V4L2_TUNER_MODE_LANG1_LANG2 audio mode

Add a new audio mode V4L2_TUNER_MODE_LANG1_LANG2 (used by VIDIOC_G/S_TUNER).
This mode allows the user to select both languages of a bilingual transmission,
one language on the left, one on the right audio channel. If there is no
bilingual transmission, or it is not supported, then this mode should act like
V4L2_TUNER_MODE_STEREO.
This mode is introduced for PVR-like drivers where it is useful to be able to
record both languages of a bilingual broadcast.

Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>
diff --git a/drivers/media/video/msp3400-kthreads.c b/drivers/media/video/msp3400-kthreads.c
index 1c794c3..c3984ea 100644
--- a/drivers/media/video/msp3400-kthreads.c
+++ b/drivers/media/video/msp3400-kthreads.c
@@ -223,9 +223,9 @@
    nor do they support stereo BTSC. */
 static void msp3400c_set_audmode(struct i2c_client *client)
 {
-	static char *strmode[] = { "mono", "stereo", "lang2", "lang1" };
+	static char *strmode[] = { "mono", "stereo", "lang2", "lang1", "lang1+lang2" };
 	struct msp_state *state = i2c_get_clientdata(client);
-	char *modestr = (state->audmode >= 0 && state->audmode < 4) ?
+	char *modestr = (state->audmode >= 0 && state->audmode < 5) ?
 		strmode[state->audmode] : "unknown";
 	int src = 0;	/* channel source: FM/AM, nicam or SCART */
 
@@ -250,6 +250,7 @@
 		case V4L2_TUNER_MODE_MONO:
 		case V4L2_TUNER_MODE_LANG1:
 		case V4L2_TUNER_MODE_LANG2:
+		case V4L2_TUNER_MODE_LANG1_LANG2:
 			msp_write_dsp(client, 0x000e, 0x3000);
 			break;
 		}
@@ -261,6 +262,7 @@
 			msp3400c_set_carrier(client, MSP_CARRIER(6.5), MSP_CARRIER(6.5));
 			break;
 		case V4L2_TUNER_MODE_STEREO:
+		case V4L2_TUNER_MODE_LANG1_LANG2:
 			msp3400c_set_carrier(client, MSP_CARRIER(7.2), MSP_CARRIER(7.02));
 			break;
 		case V4L2_TUNER_MODE_LANG1:
@@ -296,6 +298,7 @@
 	/* switch audio */
 	switch (state->audmode) {
 	case V4L2_TUNER_MODE_STEREO:
+	case V4L2_TUNER_MODE_LANG1_LANG2:
 		src |= 0x0020;
 		break;
 	case V4L2_TUNER_MODE_MONO:
@@ -835,6 +838,7 @@
 		matrix = 0x10;
 		break;
 	case V4L2_TUNER_MODE_STEREO:
+	case V4L2_TUNER_MODE_LANG1_LANG2:
 	default:
 		source = 1; /* stereo or A|B */
 		matrix = 0x20;