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| author | Antti Palosaari <crope@iki.fi> | 2012-05-15 18:32:33 -0300 |
|---|---|---|
| committer | Mauro Carvalho Chehab <mchehab@redhat.com> | 2012-05-20 10:23:18 -0300 |
| commit | eba672a045d8fbf62b229eac74ef444b6000c4c2 (patch) | |
| tree | 2247309bf56ecc8b51b07c0c08c8ca61fc2f9e56 /drivers/media | |
| parent | f6f379df6516d6fab27367706fcaafa88df41178 (diff) | |
| download | linux-eba672a045d8fbf62b229eac74ef444b6000c4c2.tar.gz linux-eba672a045d8fbf62b229eac74ef444b6000c4c2.tar.xz linux-eba672a045d8fbf62b229eac74ef444b6000c4c2.zip | |
[media] rtl2830: implement .read_snr()
Reports value as a 0.1 dB.
Signed-off-by: Antti Palosaari <crope@iki.fi>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Diffstat (limited to 'drivers/media')
| -rw-r--r-- | drivers/media/dvb/frontends/rtl2830.c | 42 | ||||
| -rw-r--r-- | drivers/media/dvb/frontends/rtl2830_priv.h | 1 |
2 files changed, 42 insertions, 1 deletions
diff --git a/drivers/media/dvb/frontends/rtl2830.c b/drivers/media/dvb/frontends/rtl2830.c index 45196c5b0736..e6d7c501717a 100644 --- a/drivers/media/dvb/frontends/rtl2830.c +++ b/drivers/media/dvb/frontends/rtl2830.c @@ -404,8 +404,48 @@ err: static int rtl2830_read_snr(struct dvb_frontend *fe, u16 *snr) { - *snr = 0; + struct rtl2830_priv *priv = fe->demodulator_priv; + int ret, hierarchy, constellation; + u8 buf[2], tmp; + u16 tmp16; +#define CONSTELLATION_NUM 3 +#define HIERARCHY_NUM 4 + static const u32 snr_constant[CONSTELLATION_NUM][HIERARCHY_NUM] = { + { 70705899, 70705899, 70705899, 70705899 }, + { 82433173, 82433173, 87483115, 94445660 }, + { 92888734, 92888734, 95487525, 99770748 }, + }; + + /* reports SNR in resolution of 0.1 dB */ + + ret = rtl2830_rd_reg(priv, 0x33c, &tmp); + if (ret) + goto err; + + constellation = (tmp >> 2) & 0x03; /* [3:2] */ + if (constellation > CONSTELLATION_NUM - 1) + goto err; + + hierarchy = (tmp >> 4) & 0x07; /* [6:4] */ + if (hierarchy > HIERARCHY_NUM - 1) + goto err; + + ret = rtl2830_rd_regs(priv, 0x40c, buf, 2); + if (ret) + goto err; + + tmp16 = buf[0] << 8 | buf[1]; + + if (tmp16) + *snr = (snr_constant[constellation][hierarchy] - + intlog10(tmp16)) / ((1 << 24) / 100); + else + *snr = 0; + return 0; +err: + dbg("%s: failed=%d", __func__, ret); + return ret; } static int rtl2830_read_ber(struct dvb_frontend *fe, u32 *ber) diff --git a/drivers/media/dvb/frontends/rtl2830_priv.h b/drivers/media/dvb/frontends/rtl2830_priv.h index 4a464761b5b8..9b20557ccf6c 100644 --- a/drivers/media/dvb/frontends/rtl2830_priv.h +++ b/drivers/media/dvb/frontends/rtl2830_priv.h @@ -22,6 +22,7 @@ #define RTL2830_PRIV_H #include "dvb_frontend.h" +#include "dvb_math.h" #include "rtl2830.h" #define LOG_PREFIX "rtl2830" |