diff options
| author | Olivier Grenie | 2009-09-15 06:46:52 -0300 |
|---|---|---|
| committer | Mauro Carvalho Chehab | 2009-09-19 00:14:10 -0300 |
| commit | ef80196490d6533e74a49509112804aa88a21c6f (patch) | |
| tree | 00df425d84700d534d4bd1fe89f5140abe20fdcf | |
| parent | 74b76f213640b4ebde9134d94a8013dbfecfcd93 (diff) | |
V4L/DVB (12887): DIB7000P: SNR calcuation forr DiB7000P
Add the SNR monitoring for the dib7000p. The result is in dB.
Signed-off-by: Olivier Grenie <olivier.grenie@dibcom.fr>
Signed-off-by: Patrick Boettcher <patrick.boettcher@dibcom.fr>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
| -rw-r--r-- | drivers/media/dvb/frontends/dib7000p.c | 33 |
1 files changed, 32 insertions, 1 deletions
diff --git a/drivers/media/dvb/frontends/dib7000p.c b/drivers/media/dvb/frontends/dib7000p.c index fc96fbf03d6d..55ef6eeb0769 100644 --- a/drivers/media/dvb/frontends/dib7000p.c +++ b/drivers/media/dvb/frontends/dib7000p.c @@ -10,6 +10,7 @@ #include <linux/kernel.h> #include <linux/i2c.h> +#include "dvb_math.h" #include "dvb_frontend.h" #include "dib7000p.h" @@ -1217,7 +1218,37 @@ static int dib7000p_read_signal_strength(struct dvb_frontend *fe, u16 *strength) static int dib7000p_read_snr(struct dvb_frontend* fe, u16 *snr) { - *snr = 0x0000; + struct dib7000p_state *state = fe->demodulator_priv; + u16 val; + s32 signal_mant, signal_exp, noise_mant, noise_exp; + u32 result = 0; + + val = dib7000p_read_word(state, 479); + noise_mant = (val >> 4) & 0xff; + noise_exp = ((val & 0xf) << 2); + val = dib7000p_read_word(state, 480); + noise_exp += ((val >> 14) & 0x3); + if ((noise_exp & 0x20) != 0) + noise_exp -= 0x40; + + signal_mant = (val >> 6) & 0xFF; + signal_exp = (val & 0x3F); + if ((signal_exp & 0x20) != 0) + signal_exp -= 0x40; + + if (signal_mant != 0) + result = intlog10(2) * 10 * signal_exp + 10 * + intlog10(signal_mant); + else + result = intlog10(2) * 10 * signal_exp - 100; + + if (noise_mant != 0) + result -= intlog10(2) * 10 * noise_exp + 10 * + intlog10(noise_mant); + else + result -= intlog10(2) * 10 * noise_exp - 100; + + *snr = result / ((1 << 24) / 10); return 0; } |