From: Daniel Scheller <d.scheller@xxxxxxx>
Original code at least has some signed/unsigned issues, resulting in
values like 32dBm. Implement signal strength readout to work without
asking the attached tuner, and use a lookup table instead of log calc.
Values reported appear plausible, gathered from feedback from several
testers.
Signed-off-by: Daniel Scheller <d.scheller@xxxxxxx>
Tested-by: Richard Scobie <r.scobie@xxxxxxxxxxxx>
---
drivers/media/dvb-frontends/stv0910.c | 48 ++++++++++++++++++++++++++++++++---
1 file changed, 44 insertions(+), 4 deletions(-)
diff --git a/drivers/media/dvb-frontends/stv0910.c b/drivers/media/dvb-frontends/stv0910.c
index dc848ebe1a44..dc4d829bb47a 100644
--- a/drivers/media/dvb-frontends/stv0910.c
+++ b/drivers/media/dvb-frontends/stv0910.c
@@ -135,7 +135,7 @@ struct sinit_table {
struct slookup {
s16 value;
- u16 reg_value;
+ u32 reg_value;
};
static inline int i2c_write(struct i2c_adapter *adap, u8 adr,
@@ -327,6 +327,25 @@ struct slookup s2_sn_lookup[] = {
{ 510, 463 }, /*C/N=51.0dB*/
};
+struct slookup padc_lookup[] = {
+ { 0, 118000 }, /* PADC=+0dBm */
+ { -100, 93600 }, /* PADC=-1dBm */
+ { -200, 74500 }, /* PADC=-2dBm */
+ { -300, 59100 }, /* PADC=-3dBm */
+ { -400, 47000 }, /* PADC=-4dBm */
+ { -500, 37300 }, /* PADC=-5dBm */
+ { -600, 29650 }, /* PADC=-6dBm */
+ { -700, 23520 }, /* PADC=-7dBm */
+ { -900, 14850 }, /* PADC=-9dBm */
+ { -1100, 9380 }, /* PADC=-11dBm */
+ { -1300, 5910 }, /* PADC=-13dBm */
+ { -1500, 3730 }, /* PADC=-15dBm */
+ { -1700, 2354 }, /* PADC=-17dBm */
+ { -1900, 1485 }, /* PADC=-19dBm */
+ { -2000, 1179 }, /* PADC=-20dBm */
+ { -2100, 1000 }, /* PADC=-21dBm */
+};
+
/*********************************************************************
* Tracking carrier loop carrier QPSK 1/4 to 8PSK 9/10 long Frame
*********************************************************************/
@@ -567,7 +586,7 @@ static int tracking_optimization(struct stv *state)
}
static s32 table_lookup(struct slookup *table,
- int table_size, u16 reg_value)
+ int table_size, u32 reg_value)
{
s32 value;
int imin = 0;
@@ -1300,11 +1319,32 @@ static int read_ber(struct dvb_frontend *fe)
static void read_signal_strength(struct dvb_frontend *fe)
{
- /* FIXME: add signal strength algo */
struct stv *state = fe->demodulator_priv;
struct dtv_frontend_properties *p = &state->fe.dtv_property_cache;
+ s64 strength;
+ u8 reg[2];
+ u16 agc;
+ s32 padc, power = 0;
+ int i;
- p->strength.stat[0].scale = FE_SCALE_NOT_AVAILABLE;
+ read_regs(state, RSTV0910_P2_AGCIQIN1 + state->regoff, reg, 2);
+
+ agc = (((u32) reg[0]) << 8) | reg[1];
+
+ for (i = 0; i < 5; i += 1) {
+ read_regs(state, RSTV0910_P2_POWERI + state->regoff, reg, 2);
+ power += (u32) reg[0] * (u32) reg[0]
+ + (u32) reg[1] * (u32) reg[1];
+ usleep_range(3000, 4000);
+ }
+ power /= 5;
+
+ padc = table_lookup(padc_lookup, ARRAY_SIZE(padc_lookup), power) + 352;
+
+ strength = (padc - agc);
+
+ p->strength.stat[0].scale = FE_SCALE_DECIBEL;
+ p->strength.stat[0].uvalue = strength;
}
static int read_status(struct dvb_frontend *fe, enum fe_status *status)
--
2.13.0
