diff options
| author | Joerg Riechardt <J.Riechardt@gmx.de> | 2015-08-29 12:02:57 -0300 |
|---|---|---|
| committer | Mauro Carvalho Chehab <mchehab@s-opensource.com> | 2016-11-23 12:41:49 -0200 |
| commit | 386701892b4821c4d127710fa35b1309c4355bbf (patch) | |
| tree | 4d15f859b09e608b59242d4e49ce929b6722f159 /drivers/media | |
| parent | 8ccd22db927995313a9ab3526c1765c7c157f3e9 (diff) | |
[media] stv090x: use lookup tables for carrier/noise ratio
The stv090x driver uses the lookup table for signal strength already,
with this patch we use the lookup tables for carrier/noise ratio as well.
This has the advantage, that values for DVB-S and DVB-S2 are now
corresponding, while before they were way off. The values are now
proportional to real carrier/noise ratio, while before they were
corresponding to register values. So now applications are able to give
the user real carrier/noise ratio.
Because the output has to be within 0x0000...0xFFFF the three negative
values for DVB-S2 are omitted. This is no significant loss, because
reception is lost at 7.5 dB already (TT S2-1600, Cine S2), so the
negative values are not really important, and also for DVB-S they don´t
exist.
Signed-off-by: Joerg Riechardt <j.riechardt@gmx.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Diffstat (limited to 'drivers/media')
| -rw-r--r-- | drivers/media/dvb-frontends/stv090x.c | 16 |
1 files changed, 10 insertions, 6 deletions
diff --git a/drivers/media/dvb-frontends/stv090x.c b/drivers/media/dvb-frontends/stv090x.c index b586d2a49737..7ef469c0c866 100644 --- a/drivers/media/dvb-frontends/stv090x.c +++ b/drivers/media/dvb-frontends/stv090x.c @@ -3692,9 +3692,12 @@ static int stv090x_read_cnr(struct dvb_frontend *fe, u16 *cnr) } val /= 16; last = ARRAY_SIZE(stv090x_s2cn_tab) - 1; - div = stv090x_s2cn_tab[0].read - - stv090x_s2cn_tab[last].read; - *cnr = 0xFFFF - ((val * 0xFFFF) / div); + div = stv090x_s2cn_tab[last].real - + stv090x_s2cn_tab[3].real; + val = stv090x_table_lookup(stv090x_s2cn_tab, last, val); + if (val < 0) + val = 0; + *cnr = val * 0xFFFF / div; } break; @@ -3714,9 +3717,10 @@ static int stv090x_read_cnr(struct dvb_frontend *fe, u16 *cnr) } val /= 16; last = ARRAY_SIZE(stv090x_s1cn_tab) - 1; - div = stv090x_s1cn_tab[0].read - - stv090x_s1cn_tab[last].read; - *cnr = 0xFFFF - ((val * 0xFFFF) / div); + div = stv090x_s1cn_tab[last].real - + stv090x_s1cn_tab[0].real; + val = stv090x_table_lookup(stv090x_s1cn_tab, last, val); + *cnr = val * 0xFFFF / div; } break; default: |