From: Daniel Scheller <d.scheller@xxxxxxx>
Original code at least has some signed/unsigned issues, resulting in
values like 32dBm. Change signal strength readout to work without asking
the attached tuner, and use a lookup table instead of log calc. Values
reported appear plausible. Obsoletes the INTLOG10X100 calc macro.
Signed-off-by: Daniel Scheller <d.scheller@xxxxxxx>
---
drivers/media/dvb-frontends/stv0910.c | 50 ++++++++++++++++++++---------------
1 file changed, 29 insertions(+), 21 deletions(-)
diff --git a/drivers/media/dvb-frontends/stv0910.c b/drivers/media/dvb-frontends/stv0910.c
index 999ee6a8ea23..c1875be01631 100644
--- a/drivers/media/dvb-frontends/stv0910.c
+++ b/drivers/media/dvb-frontends/stv0910.c
@@ -31,8 +31,6 @@
#include "stv0910.h"
#include "stv0910_regs.h"
-#define INTLOG10X100(x) ((u32) (((u64) intlog10(x) * 100) >> 24))
-
#define EXT_CLOCK 30000000
#define TUNING_DELAY 200
#define BER_SRC_S 0x20
@@ -140,7 +138,7 @@ struct SInitTable {
struct SLookup {
s16 Value;
- u16 RegValue;
+ u32 RegValue;
};
static inline int i2c_write(struct i2c_adapter *adap, u8 adr,
@@ -332,6 +330,25 @@ 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
*********************************************************************/
@@ -572,7 +589,7 @@ static int TrackingOptimization(struct stv *state)
}
static s32 TableLookup(struct SLookup *Table,
- int TableSize, u16 RegValue)
+ int TableSize, u32 RegValue)
{
s32 Value;
int imin = 0;
@@ -1300,17 +1317,18 @@ static int read_ber(struct dvb_frontend *fe, u32 *ber, u32 *n, u32 *d)
return 0;
}
-static int read_signal_strength(struct dvb_frontend *fe, u16 *strength)
+static int read_signal_strength(struct dvb_frontend *fe, s64 *strength)
{
struct stv *state = fe->demodulator_priv;
u8 Reg[2];
- s32 bbgain;
+ u16 agc;
+ s32 padc;
s32 Power = 0;
int i;
read_regs(state, RSTV0910_P2_AGCIQIN1 + state->regoff, Reg, 2);
- *strength = (((u32) Reg[0]) << 8) | Reg[1];
+ agc = (((u32) Reg[0]) << 8) | Reg[1];
for (i = 0; i < 5; i += 1) {
read_regs(state, RSTV0910_P2_POWERI + state->regoff, Reg, 2);
@@ -1320,20 +1338,9 @@ static int read_signal_strength(struct dvb_frontend *fe, u16 *strength)
}
Power /= 5;
- bbgain = (465 - INTLOG10X100(Power)) * 10;
-
- if (fe->ops.tuner_ops.get_rf_strength)
- fe->ops.tuner_ops.get_rf_strength(fe, strength);
- else
- *strength = 0;
-
- if (bbgain < (s32) *strength)
- *strength -= bbgain;
- else
- *strength = 0;
+ padc = TableLookup(padc_lookup, ARRAY_SIZE(padc_lookup), Power) + 352;
- if (*strength > 0)
- *strength = 10 * (s64) (s16) *strength - 108750;
+ *strength = (padc - agc);
return 0;
}
@@ -1463,7 +1470,8 @@ static int get_frontend(struct dvb_frontend *fe,
{
struct stv *state = fe->demodulator_priv;
enum fe_status status;
- u16 snr = 0, strength = 0;
+ u16 snr = 0;
+ s64 strength = 0;
u32 ber = 0, bernom = 0, berdenom = 0;
u8 tmp;
--
2.13.0
