V4L/DVB (13331): mxl5005s: provide ability to override QAM gain for HVR-1600

The HVR-1600 doesn't use the standard mechanism for computing the gain when
in QAM mode, instead always forcing it to be 0x02.  Provide the ability to
override the algorithm on a per-board basis.

This change results in an improvement of 0.4-0.6 dB for QAM tuning.

This work was sponsored by ONELAN Limited.

Cc: Steven Toth <stoth@kernellabs.com>
Signed-off-by: Devin Heitmueller <dheitmueller@kernellabs.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

1 files changed, 4 insertions, 0 deletions

diff --git a/drivers/media/common/tuners/mxl5005s.h b/drivers/media/common/tuners/mxl5005s.h
index 7ac6815b30aa..fc8a1ffc53b4 100644
--- a/drivers/media/common/tuners/mxl5005s.h
+++ b/drivers/media/common/tuners/mxl5005s.h
@@ -108,6 +108,10 @@ struct mxl5005s_config {
 #define MXL_LOW_IF  1
         u8 if_mode;
 
+        /* Some boards need to override the built-in logic for determining
+           the gain when in QAM mode (the HVR-1600 is one such case) */
+        u8 qam_gain;
+
         /* Stuff I don't know what to do with */
         u8 AgcMasterByte;
 };