Getting signal strength requires some loop poking with I2C.
Don't let it happen too fast.
Signed-off-by: Mauro Carvalho Chehab <mchehab@xxxxxxxxxx>
---
drivers/media/dvb-frontends/mb86a20s.c | 24 +++++++++++++++++-------
1 file changed, 17 insertions(+), 7 deletions(-)
diff --git a/drivers/media/dvb-frontends/mb86a20s.c b/drivers/media/dvb-frontends/mb86a20s.c
index 983fb3b..82fa2af 100644
--- a/drivers/media/dvb-frontends/mb86a20s.c
+++ b/drivers/media/dvb-frontends/mb86a20s.c
@@ -34,6 +34,7 @@ struct mb86a20s_state {
u32 if_freq;
u32 estimated_rate[3];
+ unsigned long get_strength_time;
bool need_init;
};
@@ -318,9 +319,17 @@ static int mb86a20s_read_status(struct dvb_frontend *fe, fe_status_t *status)
static int mb86a20s_read_signal_strength(struct dvb_frontend *fe)
{
struct mb86a20s_state *state = fe->demodulator_priv;
+ struct dtv_frontend_properties *c = &fe->dtv_property_cache;
int rc;
unsigned rf_max, rf_min, rf;
+ if (state->get_strength_time &&
+ (!time_after(jiffies, state->get_strength_time)))
+ return c->strength.stat[0].uvalue;
+
+ /* Reset its value if an error happen */
+ c->strength.stat[0].uvalue = 0;
+
/* Does a binary search to get RF strength */
rf_max = 0xfff;
rf_min = 0;
@@ -350,15 +359,19 @@ static int mb86a20s_read_signal_strength(struct dvb_frontend *fe)
rf = (rf_max + rf_min) / 2;
/* Rescale it from 2^12 (4096) to 2^16 */
- rf <<= (16 - 12);
+ rf = rf << (16 - 12);
+ if (rf)
+ rf |= (1 << 12) - 1;
+
dev_dbg(&state->i2c->dev,
"%s: signal strength = %d (%d < RF=%d < %d)\n",
__func__, rf, rf_min, rf >> 4, rf_max);
- return rf;
+ c->strength.stat[0].uvalue = rf;
+ state->get_strength_time = jiffies +
+ msecs_to_jiffies(1000);
+ return 0;
}
} while (1);
-
- return 0;
}
static int mb86a20s_get_modulation(struct mb86a20s_state *state,
@@ -1882,7 +1895,6 @@ static int mb86a20s_read_status_and_stats(struct dvb_frontend *fe,
fe_status_t *status)
{
struct mb86a20s_state *state = fe->demodulator_priv;
- struct dtv_frontend_properties *c = &fe->dtv_property_cache;
int rc, status_nr;
dev_dbg(&state->i2c->dev, "%s called.\n", __func__);
@@ -1913,8 +1925,6 @@ static int mb86a20s_read_status_and_stats(struct dvb_frontend *fe,
rc = 0; /* Status is OK */
goto error;
}
- /* Fill signal strength */
- c->strength.stat[0].uvalue = rc;
if (status_nr >= 7) {
/* Get TMCC info*/
--
1.8.1.4
--
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