From c6e62a3a398d62e8ae366ac1465911db0ac7fc0b Mon Sep 17 00:00:00 2001
From: Chris Pascoe <c.pascoe@itee.uq.edu.au>
Date: Tue, 20 Nov 2007 02:49:41 -0300
Subject: [PATCH] V4L/DVB (6654): mt352: support oversampled IF input
Rework the input frequency calculation so that it produces the right values
when the ADC oversamples the IF input.
This means MT352 devices can now process a near-zero IF (according to the,
specs 4.57MHz is supported with the default crystal).
Signed-off-by: Chris Pascoe <c.pascoe@itee.uq.edu.au>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>
---
drivers/media/dvb/frontends/mt352.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/drivers/media/dvb/frontends/mt352.c b/drivers/media/dvb/frontends/mt352.c
index 5dd9b731f6f2..7cd190b6f015 100644
--- a/drivers/media/dvb/frontends/mt352.c
+++ b/drivers/media/dvb/frontends/mt352.c
@@ -152,7 +152,13 @@ static void mt352_calc_input_freq(struct mt352_state* state,
if (state->config.if2)
if2 = state->config.if2;
- ife = (2*adc_clock - if2);
+ if (adc_clock >= if2 * 2)
+ ife = if2;
+ else {
+ ife = adc_clock - (if2 % adc_clock);
+ if (ife > adc_clock / 2)
+ ife = adc_clock - ife;
+ }
value = -16374 * ife / adc_clock;
dprintk("%s: if2 %d, ife %d, adc_clock %d => %d / 0x%x\n",
__FUNCTION__, if2, ife, adc_clock, value, value & 0x3fff);
--
GitLab