[media] mb86a20s: don't allow updating signal strength too fast
Getting signal strength requires some loop poking with I2C.
Don't let it happen too fast.
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
diff --git a/drivers/media/dvb-frontends/mb86a20s.c b/drivers/media/dvb-frontends/mb86a20s.c
index 0fbfae2..9948fcb 100644
--- a/drivers/media/dvb-frontends/mb86a20s.c
+++ b/drivers/media/dvb-frontends/mb86a20s.c
@@ -34,6 +34,7 @@
u32 if_freq;
u32 estimated_rate[3];
+ unsigned long get_strength_time;
bool need_init;
};
@@ -318,9 +319,17 @@
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 @@
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 @@
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 @@
rc = 0; /* Status is OK */
goto error;
}
- /* Fill signal strength */
- c->strength.stat[0].uvalue = rc;
if (status_nr >= 7) {
/* Get TMCC info*/