From 2ca58f45cc986952dc2b2942fb170d9d7644735a Mon Sep 17 00:00:00 2001 From: Antti Palosaari Date: Thu, 26 Mar 2015 10:49:17 -0300 Subject: [PATCH] [media] ts2020: improve filter limit calc * We don't need calculate channel bandwidth from symbol rate as it is calculated by DVB core. * Use clamp() to force upper/lower limit of filter 3dB frequency. Upper limit should never exceeded 40MHz (80MHz BW) in any case, though... Signed-off-by: Antti Palosaari Signed-off-by: Mauro Carvalho Chehab --- drivers/media/dvb-frontends/ts2020.c | 10 +++------- 1 file changed, 3 insertions(+), 7 deletions(-) diff --git a/drivers/media/dvb-frontends/ts2020.c b/drivers/media/dvb-frontends/ts2020.c index bc48388906d3..590f7e1b56f3 100644 --- a/drivers/media/dvb-frontends/ts2020.c +++ b/drivers/media/dvb-frontends/ts2020.c @@ -233,7 +233,6 @@ static int ts2020_set_params(struct dvb_frontend *fe) struct dtv_frontend_properties *c = &fe->dtv_property_cache; struct ts2020_priv *priv = fe->tuner_priv; int ret; - u32 symbol_rate = (c->symbol_rate / 1000); u32 f3db, gdiv28; u16 u16tmp, value, lpf_coeff; u8 buf[3], reg10, lpf_mxdiv, mlpf_max, mlpf_min, nlpf; @@ -312,12 +311,9 @@ static int ts2020_set_params(struct dvb_frontend *fe) value = ts2020_readreg(fe, 0x26); - f3db = (symbol_rate * 135) / 200 + 2000; - f3db += FREQ_OFFSET_LOW_SYM_RATE; - if (f3db < 7000) - f3db = 7000; - if (f3db > 40000) - f3db = 40000; + f3db = (c->bandwidth_hz / 1000 / 2) + 2000; + f3db += FREQ_OFFSET_LOW_SYM_RATE; /* FIXME: ~always too wide filter */ + f3db = clamp(f3db, 7000U, 40000U); gdiv28 = gdiv28 * 207 / (value * 2 + 151); mlpf_max = gdiv28 * 135 / 100; -- 2.20.1