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authorChris Pascoe <c.pascoe@itee.uq.edu.au>2007-12-02 09:39:18 -0300
committerMauro Carvalho Chehab <mchehab@infradead.org>2008-01-25 19:04:01 -0200
commit897b842296f1285a6b58e9170f7017022e2e2603 (patch)
tree9022cc9d3215dc562dc2d702d7a521c6f961db11
parent9ca01e780f8966a7a94f88ef5c54f340e117abea (diff)
V4L/DVB (6854): xc2028: be more specific about when applying offset for 7MHz channels
We have been inserting a mystery 500kHz offset for tuning 7MHz channels, however some experimentation reveals it is only needed under certain conditions with specific firmware combinations. Document these and only apply the offset when we know it is required. Signed-off-by: Chris Pascoe <c.pascoe@itee.uq.edu.au> Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>
-rw-r--r--drivers/media/video/tuner-xc2028.c11
1 files changed, 10 insertions, 1 deletions
diff --git a/drivers/media/video/tuner-xc2028.c b/drivers/media/video/tuner-xc2028.c
index a6b05dfd670..63a6fca1f8c 100644
--- a/drivers/media/video/tuner-xc2028.c
+++ b/drivers/media/video/tuner-xc2028.c
@@ -875,7 +875,16 @@ static int generic_set_freq(struct dvb_frontend *fe, u32 freq /* in HZ */,
rc = send_seq(priv, {0x00, 0x00});
} else {
offset = 2750000;
- if (priv->cur_fw.type & DTV7)
+ /*
+ * We must adjust the offset by 500kHz in two cases in order
+ * to correctly center the IF output:
+ * 1) When the ZARLINK456 or DIBCOM52 tables were explicitly
+ * selected and a 7MHz channel is tuned;
+ * 2) When tuning a VHF channel with DTV78 firmware.
+ */
+ if (((priv->cur_fw.type & DTV7) &&
+ (priv->cur_fw.scode_table & (ZARLINK456 | DIBCOM52))) ||
+ ((priv->cur_fw.type & DTV78) && freq < 470000000))
offset -= 500000;
}