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| author | Chris Pascoe <c.pascoe@itee.uq.edu.au> | 2007-11-20 15:49:41 +1000 |
|---|---|---|
| committer | Chris Pascoe <c.pascoe@itee.uq.edu.au> | 2007-11-20 15:49:41 +1000 |
| commit | 9df8e9ae7eaa584016ee314cb07a4717097a4a64 (patch) | |
| tree | b0a6898d6da86d4b0a909771f931c643092625b8 /linux | |
| parent | 9ab766dfc4a7509e2c313383b8a18a750892f6d1 (diff) | |
| download | mediapointer-dvb-s2-9df8e9ae7eaa584016ee314cb07a4717097a4a64.tar.gz mediapointer-dvb-s2-9df8e9ae7eaa584016ee314cb07a4717097a4a64.tar.bz2 | |
mt352: support oversampled IF input
From: Chris Pascoe <c.pascoe@itee.uq.edu.au>
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>
Diffstat (limited to 'linux')
| -rw-r--r-- | linux/drivers/media/dvb/frontends/mt352.c | 8 |
1 files changed, 7 insertions, 1 deletions
diff --git a/linux/drivers/media/dvb/frontends/mt352.c b/linux/drivers/media/dvb/frontends/mt352.c index c9500f58a..f9eb120c0 100644 --- a/linux/drivers/media/dvb/frontends/mt352.c +++ b/linux/drivers/media/dvb/frontends/mt352.c @@ -153,7 +153,13 @@ 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); |