From 9df8e9ae7eaa584016ee314cb07a4717097a4a64 Mon Sep 17 00:00:00 2001 From: Chris Pascoe Date: Tue, 20 Nov 2007 15:49:41 +1000 Subject: mt352: support oversampled IF input From: Chris Pascoe 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 Signed-off-by: Mauro Carvalho Chehab --- linux/drivers/media/dvb/frontends/mt352.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) (limited to 'linux') 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); -- cgit v1.2.3