Implement dvbv5 signal strength estimate. We know tuner dependent
-80dBm and -50dBm agc values, construct line equation and use it to
map agc value to signal strength estimate.
Signed-off-by: Antti Palosaari <crope@xxxxxx>
---
drivers/media/dvb-frontends/af9013.c | 83 +++++++++++++++++++++++++++++++++++-
1 file changed, 81 insertions(+), 2 deletions(-)
diff --git a/drivers/media/dvb-frontends/af9013.c b/drivers/media/dvb-frontends/af9013.c
index 30cf837058da..4cb6371572c5 100644
--- a/drivers/media/dvb-frontends/af9013.c
+++ b/drivers/media/dvb-frontends/af9013.c
@@ -41,8 +41,11 @@ struct af9013_state {
u16 snr;
u32 bandwidth_hz;
enum fe_status fe_status;
+ /* RF and IF AGC limits used for signal strength calc */
+ u8 strength_en, rf_agc_50, rf_agc_80, if_agc_50, if_agc_80;
unsigned long set_frontend_jiffies;
unsigned long read_status_jiffies;
+ unsigned long strength_jiffies;
bool first_tune;
bool i2c_gate_state;
unsigned int statistics_step:3;
@@ -751,8 +754,12 @@ static int af9013_read_status(struct dvb_frontend *fe, enum fe_status *status)
{
struct af9013_state *state = fe->demodulator_priv;
struct i2c_client *client = state->client;
- int ret;
- unsigned int utmp, utmp1;
+ struct dtv_frontend_properties *c = &fe->dtv_property_cache;
+ int ret, stmp1;
+ unsigned int utmp, utmp1, utmp2, utmp3, utmp4;
+ u8 buf[2];
+
+ dev_dbg(&client->dev, "\n");
/*
* Return status from the cache if it is younger than 2000ms with the
@@ -791,6 +798,77 @@ static int af9013_read_status(struct dvb_frontend *fe, enum fe_status *status)
*status = utmp1;
}
+ /* Signal strength */
+ switch (state->strength_en) {
+ case 0:
+ /* Check if we support signal strength */
+ ret = regmap_read(state->regmap, 0x9bee, &utmp);
+ if (ret)
+ goto err;
+
+ if ((utmp >> 0) & 0x01) {
+ /* Read agc values for signal strength estimation */
+ ret = regmap_read(state->regmap, 0x9bbd, &utmp1);
+ if (ret)
+ goto err;
+ ret = regmap_read(state->regmap, 0x9bd0, &utmp2);
+ if (ret)
+ goto err;
+ ret = regmap_read(state->regmap, 0x9be2, &utmp3);
+ if (ret)
+ goto err;
+ ret = regmap_read(state->regmap, 0x9be4, &utmp4);
+ if (ret)
+ goto err;
+
+ state->rf_agc_50 = utmp1;
+ state->rf_agc_80 = utmp2;
+ state->if_agc_50 = utmp3;
+ state->if_agc_80 = utmp4;
+ dev_dbg(&client->dev,
+ "rf_agc_50 %u, rf_agc_80 %u, if_agc_50 %u, if_agc_80 %u\n",
+ utmp1, utmp2, utmp3, utmp4);
+
+ state->strength_en = 1;
+ } else {
+ /* Signal strength is not supported */
+ state->strength_en = 2;
+ break;
+ }
+ /* Fall through */
+ case 1:
+ if (time_is_after_jiffies(state->strength_jiffies + msecs_to_jiffies(2000)))
+ break;
+
+ /* Read value */
+ ret = regmap_bulk_read(state->regmap, 0xd07c, buf, 2);
+ if (ret)
+ goto err;
+
+ /*
+ * Construct line equation from tuner dependent -80/-50 dBm agc
+ * limits and use it to map current agc value to dBm estimate
+ */
+ #define agc_gain (buf[0] + buf[1])
+ #define agc_gain_50dbm (state->rf_agc_50 + state->if_agc_50)
+ #define agc_gain_80dbm (state->rf_agc_80 + state->if_agc_80)
+ stmp1 = 30000 * (agc_gain - agc_gain_80dbm) /
+ (agc_gain_50dbm - agc_gain_80dbm) - 80000;
+
+ dev_dbg(&client->dev,
+ "strength %d, agc_gain %d, agc_gain_50dbm %d, agc_gain_80dbm %d\n",
+ stmp1, agc_gain, agc_gain_50dbm, agc_gain_80dbm);
+
+ state->strength_jiffies = jiffies;
+
+ c->strength.stat[0].scale = FE_SCALE_DECIBEL;
+ c->strength.stat[0].svalue = stmp1;
+ break;
+ default:
+ c->strength.stat[0].scale = FE_SCALE_NOT_AVAILABLE;
+ break;
+ }
+
return 0;
err:
dev_dbg(&client->dev, "failed %d\n", ret);
@@ -1512,6 +1590,7 @@ static int af9013_probe(struct i2c_client *client,
/* Init stats to indicate which stats are supported */
c = &state->fe.dtv_property_cache;
+ c->strength.len = 1;
c->cnr.len = 1;
dev_info(&client->dev, "Afatech AF9013 successfully attached\n");
--
2.14.3
