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[media] af9013: cache some reg values to reduce reg reads

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Demod + tuner specific RF AGC and IF AGC limit values are read from demod
memory in every signal strength query. Cache those to reduce I2C traffic.

Signed-off-by: Antti Palosaari <crope@iki.fi>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
This commit is contained in:
Antti Palosaari 2010-10-07 16:34:55 -03:00 committed by Mauro Carvalho Chehab
parent edb709b61a
commit 9e35cd222b
1 changed files with 32 additions and 23 deletions
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55
drivers/media/dvb/frontends/af9013.c
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@ -42,6 +42,8 @@ struct af9013_state {
struct af9013_config config;
/* tuner/demod RF and IF AGC limits used for signal strength calc */
u8 signal_strength_en, rf_50, rf_80, if_50, if_80;
u16 signal_strength;
u32 ber;
u32 ucblocks;
@ -963,45 +965,31 @@ static int af9013_update_signal_strength(struct dvb_frontend *fe)
{
struct af9013_state *state = fe->demodulator_priv;
int ret;
u8 tmp0;
u8 rf_gain, rf_50, rf_80, if_gain, if_50, if_80;
u8 rf_gain, if_gain;
int signal_strength;
deb_info("%s\n", __func__);
state->signal_strength = 0;
ret = af9013_read_reg_bits(state, 0x9bee, 0, 1, &tmp0);
if (ret)
goto error;
if (tmp0) {
ret = af9013_read_reg(state, 0x9bbd, &rf_50);
if (ret)
goto error;
ret = af9013_read_reg(state, 0x9bd0, &rf_80);
if (ret)
goto error;
ret = af9013_read_reg(state, 0x9be2, &if_50);
if (ret)
goto error;
ret = af9013_read_reg(state, 0x9be4, &if_80);
if (ret)
goto error;
if (state->signal_strength_en) {
ret = af9013_read_reg(state, 0xd07c, &rf_gain);
if (ret)
goto error;
ret = af9013_read_reg(state, 0xd07d, &if_gain);
if (ret)
goto error;
signal_strength = (0xffff / (9 * (rf_50 + if_50) - \
11 * (rf_80 + if_80))) * (10 * (rf_gain + if_gain) - \
11 * (rf_80 + if_80));
signal_strength = (0xffff / \
(9 * (state->rf_50 + state->if_50) - \
11 * (state->rf_80 + state->if_80))) * \
(10 * (rf_gain + if_gain) - \
11 * (state->rf_80 + state->if_80));
if (signal_strength < 0)
signal_strength = 0;
else if (signal_strength > 0xffff)
signal_strength = 0xffff;
state->signal_strength = signal_strength;
} else {
state->signal_strength = 0;
}
error:
@ -1306,6 +1294,27 @@ static int af9013_init(struct dvb_frontend *fe)
if (ret)
goto error;
/* read values needed for signal strength calculation */
ret = af9013_read_reg_bits(state, 0x9bee, 0, 1,
&state->signal_strength_en);
if (ret)
goto error;
if (state->signal_strength_en) {
ret = af9013_read_reg(state, 0x9bbd, &state->rf_50);
if (ret)
goto error;
ret = af9013_read_reg(state, 0x9bd0, &state->rf_80);
if (ret)
goto error;
ret = af9013_read_reg(state, 0x9be2, &state->if_50);
if (ret)
goto error;
ret = af9013_read_reg(state, 0x9be4, &state->if_80);
if (ret)
goto error;
}
error:
return ret;
}