diff options
| author | Mauro Carvalho Chehab <mchehab@redhat.com> | 2013-03-02 10:15:30 -0300 |
|---|---|---|
| committer | Mauro Carvalho Chehab <mchehab@redhat.com> | 2013-03-04 16:33:43 -0300 |
| commit | 0921ecfdc2b93ebbe8f2371dac634d91e4fbdf60 (patch) | |
| tree | bdb3955c1f2970941458069a7cd118d947f5d6c1 /drivers/media/dvb-frontends/mb86a20s.c | |
| parent | dad78c56620d425eede52d74e8ba73ea136703dd (diff) | |
| download | linux-next-0921ecfdc2b93ebbe8f2371dac634d91e4fbdf60.tar.gz | |
[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>
Diffstat (limited to 'drivers/media/dvb-frontends/mb86a20s.c')
| -rw-r--r-- | drivers/media/dvb-frontends/mb86a20s.c | 24 |
1 files changed, 17 insertions, 7 deletions
diff --git a/drivers/media/dvb-frontends/mb86a20s.c b/drivers/media/dvb-frontends/mb86a20s.c index 0fbfae23d904..9948fcbf1596 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*/ |