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media: dvb-frontends/stv0367: SNR DVBv5 statistics for DVB-C and T 

Add signal-to-noise-ratio as provided by the demodulator in decibel scale.
QAM/DVB-C needs some intlog calculation to have usable dB values, OFDM/
DVB-T values from the demod look alright already and are provided as-is.

Signed-off-by: Daniel Scheller <d.scheller@gmx.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
This commit is contained in:
Daniel Scheller 2017-06-25 08:26:44 -03:00 committed by Mauro Carvalho Chehab
parent 8982735f8d
commit d394ad12c2
1 changed files with 39 additions and 0 deletions
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39
drivers/media/dvb-frontends/stv0367.c
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@ -25,6 +25,8 @@
#include <linux/slab.h>
#include <linux/i2c.h>
#include "dvb_math.h"
#include "stv0367.h"
#include "stv0367_defs.h"
#include "stv0367_regs.h"
@ -2996,6 +2998,37 @@ static int stv0367ddb_set_frontend(struct dvb_frontend *fe)
return -EINVAL;
}
static void stv0367ddb_read_snr(struct dvb_frontend *fe)
{
struct stv0367_state *state = fe->demodulator_priv;
struct dtv_frontend_properties *p = &fe->dtv_property_cache;
int cab_pwr;
u32 regval, tmpval, snrval = 0;
switch (state->activedemod) {
case demod_ter:
snrval = stv0367ter_snr_readreg(fe);
break;
case demod_cab:
cab_pwr = stv0367cab_snr_power(fe);
regval = stv0367cab_snr_readreg(fe, 0);
/* prevent division by zero */
if (!regval)
snrval = 0;
tmpval = (cab_pwr * 320) / regval;
snrval = ((tmpval != 0) ? (intlog2(tmpval) / 5581) : 0);
break;
default:
p->cnr.stat[0].scale = FE_SCALE_NOT_AVAILABLE;
return;
}
p->cnr.stat[0].scale = FE_SCALE_DECIBEL;
p->cnr.stat[0].uvalue = snrval;
}
static void stv0367ddb_read_ucblocks(struct dvb_frontend *fe)
{
struct stv0367_state *state = fe->demodulator_priv;
@ -3040,6 +3073,12 @@ static int stv0367ddb_read_status(struct dvb_frontend *fe,
if (ret)
return ret;
/* read carrier/noise when a carrier is detected */
if (*status & FE_HAS_CARRIER)
stv0367ddb_read_snr(fe);
else
p->cnr.stat[0].scale = FE_SCALE_NOT_AVAILABLE;
/* stop if demod isn't locked */
if (!(*status & FE_HAS_LOCK)) {
p->block_error.stat[0].scale = FE_SCALE_NOT_AVAILABLE;