V4L/DVB (3275): Allow SAA7134 to fall back to AM sound when there is NICAM-L

This patch allows to select AM sound even if NICAM is detected.
Proposed by Alain Frappin
Signed-off-by: Hartmut Hackmann <hartmut.hackmann@t-online.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>

drivers/media/video/saa7134/saa7134-tvaudio.c

@@ -139,6 +139,12 @@ static struct saa7134_tvaudio tvaudio[] = {
 		.carr1         = 6500,
 		.carr2         = 5850,
 		.mode          = TVAUDIO_NICAM_AM,
+	},{
+		.name          = "SECAM-L MONO",
+		.std           = V4L2_STD_SECAM,
+		.carr1         = 6500,
+		.carr2         = -1,
+		.mode          = TVAUDIO_AM_MONO,
 	},{
 		.name          = "SECAM-D/K",
 		.std           = V4L2_STD_SECAM,
@@ -334,6 +340,12 @@ static void tvaudio_setmode(struct saa7134_dev *dev,
 		saa_writeb(SAA7134_STEREO_DAC_OUTPUT_SELECT,  0xa1);
 		saa_writeb(SAA7134_NICAM_CONFIG,              0x00);
 		break;
+	case TVAUDIO_AM_MONO:
+		saa_writeb(SAA7134_DEMODULATOR,               0x12);
+		saa_writeb(SAA7134_DCXO_IDENT_CTRL,           0x00);
+		saa_writeb(SAA7134_FM_DEEMPHASIS,             0x44);
+		saa_writeb(SAA7134_STEREO_DAC_OUTPUT_SELECT,  0xa0);
+		break;
 	case TVAUDIO_FM_SAT_STEREO:
 		/* not implemented (yet) */
 		break;
@@ -414,6 +426,7 @@ static int tvaudio_getstereo(struct saa7134_dev *dev, struct saa7134_tvaudio *au
 
 	switch (audio->mode) {
 	case TVAUDIO_FM_MONO:
+	case TVAUDIO_AM_MONO:
 		return V4L2_TUNER_SUB_MONO;
 	case TVAUDIO_FM_K_STEREO:
 	case TVAUDIO_FM_BG_STEREO:
@@ -480,6 +493,7 @@ static int tvaudio_setstereo(struct saa7134_dev *dev, struct saa7134_tvaudio *au
 
 	switch (audio->mode) {
 	case TVAUDIO_FM_MONO:
+	case TVAUDIO_AM_MONO:
 		/* nothing to do ... */
 		break;
 	case TVAUDIO_FM_K_STEREO:

drivers/media/video/saa7134/saa7134.h

@@ -60,6 +60,7 @@ enum saa7134_tvaudio_mode {
 	TVAUDIO_FM_K_STEREO   = 4,
 	TVAUDIO_NICAM_AM      = 5,
 	TVAUDIO_NICAM_FM      = 6,
+	TVAUDIO_AM_MONO	      = 7
 };
 
 enum saa7134_audio_in {