diff options
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/media/dvb/frontends/au8522_dig.c | 31 |
1 files changed, 30 insertions, 1 deletions
diff --git a/drivers/media/dvb/frontends/au8522_dig.c b/drivers/media/dvb/frontends/au8522_dig.c index 1d572940e24..5c0d3989f5b 100644 --- a/drivers/media/dvb/frontends/au8522_dig.c +++ b/drivers/media/dvb/frontends/au8522_dig.c @@ -862,7 +862,36 @@ static int au8522_read_snr(struct dvb_frontend *fe, u16 *snr) static int au8522_read_signal_strength(struct dvb_frontend *fe, u16 *signal_strength) { - return au8522_read_snr(fe, signal_strength); + /* borrowed from lgdt330x.c + * + * Calculate strength from SNR up to 35dB + * Even though the SNR can go higher than 35dB, + * there is some comfort factor in having a range of + * strong signals that can show at 100% + */ + u16 snr; + u32 tmp; + int ret = au8522_read_snr(fe, &snr); + + *signal_strength = 0; + + if (0 == ret) { + /* The following calculation method was chosen + * purely for the sake of code re-use from the + * other demod drivers that use this method */ + + /* Convert from SNR in dB * 10 to 8.24 fixed-point */ + tmp = (snr * ((1 << 24) / 10)); + + /* Convert from 8.24 fixed-point to + * scale the range 0 - 35*2^24 into 0 - 65535*/ + if (tmp >= 8960 * 0x10000) + *signal_strength = 0xffff; + else + *signal_strength = tmp / 8960; + } + + return ret; } static int au8522_read_ucblocks(struct dvb_frontend *fe, u32 *ucblocks) |