static ssize_t apds990x_set_lux_thresh(struct apds990x_chip *chip, u32 *target,
const char *buf)
{
unsigned long thresh;
int ret;
ret = kstrtoul(buf, 0, &thresh);
if (ret)
return ret;
if (thresh > APDS_RANGE)
return -EINVAL;
mutex_lock(&chip->mutex);
*target = thresh;
/*
* Don't update values in HW if we are still waiting for
* first interrupt to come after device handle open call.
*/
if (!chip->lux_wait_fresh_res)
apds990x_refresh_athres(chip);
mutex_unlock(&chip->mutex);
return ret;
}
/* Called always with mutex locked */
static int apds990x_calc_again(struct apds990x_chip *chip)
{
int curr_again = chip->again_meas;
int next_again = chip->again_meas;
int ret = 0;
/* Calculate suitable als gain */
if (chip->lux_clear == chip->a_max_result)
next_again -= 2; /* ALS saturated. Decrease gain by 2 steps */
else if (chip->lux_clear > chip->a_max_result / 2)
next_again--;
else if (chip->lux_clear < APDS_LUX_GAIN_LO_LIMIT_STRICT)
next_again += 2; /* Too dark. Increase gain by 2 steps */
else if (chip->lux_clear < APDS_LUX_GAIN_LO_LIMIT)
next_again++;
/* Limit gain to available range */
if (next_again < 0)
next_again = 0;
else if (next_again > APDS990X_MAX_AGAIN)
next_again = APDS990X_MAX_AGAIN;
/* Let's check can we trust the measured result */
if (chip->lux_clear == chip->a_max_result)
/* Result can be totally garbage due to saturation */
ret = -ERANGE;
else if (next_again != curr_again &&
chip->lux_clear < APDS_LUX_GAIN_LO_LIMIT_STRICT)
/*
* Gain is changed and measurement result is very small.
* Result can be totally garbage due to underflow
*/
ret = -ERANGE;
chip->again_next = next_again;
apds990x_write_byte(chip, APDS990X_CONTROL,
(chip->pdrive << 6) |
(chip->pdiode << 4) |
(chip->pgain << 2) |
(chip->again_next << 0));
/*
* Error means bad result -> re-measurement is needed. The forced
* refresh uses fastest possible persistence setting to get result
* as soon as possible.
*/
if (ret < 0)
apds990x_force_a_refresh(chip);
else
apds990x_refresh_athres(chip);
return ret;
}
