[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 <crope@iki.fi>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>

diff --git a/drivers/media/dvb-frontends/ts2020.c b/drivers/media/dvb-frontends/ts2020.c
index bc48388906d33343218817a7bb3046d0393b5621..590f7e1b56f3a45a0c3dc4ac6f617afba1bd4f00 100644 (file)
--- 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;