V4L/DVB (13232): cx25840 6.5MHz carrier detection fixes

cx25840:
Disable 6.5MHz carrier autodetection for PAL, always assume its DK.
Only try to autodetect 6.5MHz carrier for SECAM if user accepts both
system DK and L.

Signed-off-by: Aleksandr V. Piskunov <alexandr.v.piskunov@gmail.com>
Reviewed-by: Andy Walls <awalls@radix.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

1 files changed, 21 insertions, 4 deletions

diff --git a/drivers/media/video/cx25840/cx25840-core.c b/drivers/media/video/cx25840/cx25840-core.c
index 9702a9334b4a..385ecd58f1c0 100644
--- a/drivers/media/video/cx25840/cx25840-core.c
+++ b/drivers/media/video/cx25840/cx25840-core.c
@@ -685,13 +685,30 @@ static void input_change(struct i2c_client *client)
                 }
                 cx25840_write(client, 0x80b, 0x00);
         } else if (std & V4L2_STD_PAL) {
-                /* Follow tuner change procedure for PAL */
+                /* Autodetect audio standard and audio system */
                 cx25840_write(client, 0x808, 0xff);
-                cx25840_write(client, 0x80b, 0x10);
+                /* Since system PAL-L is pretty much non-existant and
+                   not used by any public broadcast network, force
+                   6.5 MHz carrier to be interpreted as System DK,
+                   this avoids DK audio detection instability */
+               cx25840_write(client, 0x80b, 0x00);
         } else if (std & V4L2_STD_SECAM) {
-                /* Select autodetect for SECAM */
+                /* Autodetect audio standard and audio system */
                 cx25840_write(client, 0x808, 0xff);
-                cx25840_write(client, 0x80b, 0x10);
+                /* If only one of SECAM-DK / SECAM-L is required, then force
+                  6.5MHz carrier, else autodetect it */
+                if ((std & V4L2_STD_SECAM_DK) &&
+                    !(std & (V4L2_STD_SECAM_L | V4L2_STD_SECAM_LC))) {
+                        /* 6.5 MHz carrier to be interpreted as System DK */
+                        cx25840_write(client, 0x80b, 0x00);
+               } else if (!(std & V4L2_STD_SECAM_DK) &&
+                          (std & (V4L2_STD_SECAM_L | V4L2_STD_SECAM_LC))) {
+                        /* 6.5 MHz carrier to be interpreted as System L */
+                        cx25840_write(client, 0x80b, 0x08);
+               } else {
+                        /* 6.5 MHz carrier to be autodetected */
+                        cx25840_write(client, 0x80b, 0x10);
+               }
         }
 
         cx25840_and_or(client, 0x810, ~0x01, 0);