static u32 calculate_snr(u32 mse, u32 c)
{
if (mse == 0) /* No signal */
return 0;
mse = 2*intlog10(mse);
if (mse > c) {
/* Negative SNR, which is possible, but realisticly the
demod will lose lock before the signal gets this bad. The
API only allows for unsigned values, so just return 0 */
return 0;
}
return 10*(c - mse);
}
static int mtvhd_fe_read_snr(struct dvb_frontend *fe, u16 *snr)
{
int ret;
u32 val, x;
deb_info("FE read snr: ");
*snr = 0;
ret = mtvhd_demod_reg_read(fe, 0x8B);
if (ret < 0) {
goto done;
}
val = ret << 16;
ret = mtvhd_demod_reg_read(fe, 0x8C);
if (ret < 0) {
goto done;
}
val |= ret << 8;
ret = mtvhd_demod_reg_read(fe, 0x8D);
if (ret < 0) {
goto done;
}
val |= ret;
ret = 0;
deb_info("%06x -> ", val);
if (val == 0 || val > 0x540000) {
goto done;
}
x = 20 * intlog10(0x540000 / val);
*snr = (u16)(x >> 16);
done:
deb_info("%04x (%d.%d dB)\n", *snr, *snr >> 8, ((*snr & 0xFF) * 10) >> 8);
return ret;
}
static int m88ds3103_read_status(struct dvb_frontend *fe,
enum fe_status *status)
{
struct m88ds3103_dev *dev = fe->demodulator_priv;
struct i2c_client *client = dev->client;
struct dtv_frontend_properties *c = &fe->dtv_property_cache;
int ret, i, itmp;
unsigned int utmp;
u8 buf[3];
*status = 0;
if (!dev->warm) {
ret = -EAGAIN;
goto err;
}
switch (c->delivery_system) {
case SYS_DVBS:
ret = regmap_read(dev->regmap, 0xd1, &utmp);
if (ret)
goto err;
if ((utmp & 0x07) == 0x07)
*status = FE_HAS_SIGNAL | FE_HAS_CARRIER |
FE_HAS_VITERBI | FE_HAS_SYNC |
FE_HAS_LOCK;
break;
case SYS_DVBS2:
ret = regmap_read(dev->regmap, 0x0d, &utmp);
if (ret)
goto err;
if ((utmp & 0x8f) == 0x8f)
*status = FE_HAS_SIGNAL | FE_HAS_CARRIER |
FE_HAS_VITERBI | FE_HAS_SYNC |
FE_HAS_LOCK;
break;
default:
dev_dbg(&client->dev, "invalid delivery_system\n");
ret = -EINVAL;
goto err;
}
dev->fe_status = *status;
dev_dbg(&client->dev, "lock=%02x status=%02x\n", utmp, *status);
/* CNR */
if (dev->fe_status & FE_HAS_VITERBI) {
unsigned int cnr, noise, signal, noise_tot, signal_tot;
cnr = 0;
/* more iterations for more accurate estimation */
#define M88DS3103_SNR_ITERATIONS 3
switch (c->delivery_system) {
case SYS_DVBS:
itmp = 0;
for (i = 0; i < M88DS3103_SNR_ITERATIONS; i++) {
ret = regmap_read(dev->regmap, 0xff, &utmp);
if (ret)
goto err;
itmp += utmp;
}
/* use of single register limits max value to 15 dB */
/* SNR(X) dB = 10 * ln(X) / ln(10) dB */
itmp = DIV_ROUND_CLOSEST(itmp, 8 * M88DS3103_SNR_ITERATIONS);
if (itmp)
cnr = div_u64((u64) 10000 * intlog2(itmp), intlog2(10));
break;
case SYS_DVBS2:
noise_tot = 0;
signal_tot = 0;
for (i = 0; i < M88DS3103_SNR_ITERATIONS; i++) {
ret = regmap_bulk_read(dev->regmap, 0x8c, buf, 3);
if (ret)
goto err;
noise = buf[1] << 6; /* [13:6] */
noise |= buf[0] & 0x3f; /* [5:0] */
noise >>= 2;
signal = buf[2] * buf[2];
signal >>= 1;
noise_tot += noise;
signal_tot += signal;
}
noise = noise_tot / M88DS3103_SNR_ITERATIONS;
signal = signal_tot / M88DS3103_SNR_ITERATIONS;
/* SNR(X) dB = 10 * log10(X) dB */
if (signal > noise) {
itmp = signal / noise;
cnr = div_u64((u64) 10000 * intlog10(itmp), (1 << 24));
}
break;
default:
dev_dbg(&client->dev, "invalid delivery_system\n");
ret = -EINVAL;
goto err;
}
if (cnr) {
c->cnr.stat[0].scale = FE_SCALE_DECIBEL;
c->cnr.stat[0].svalue = cnr;
} else {
c->cnr.stat[0].scale = FE_SCALE_NOT_AVAILABLE;
}
} else {
