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iio: adc: ti-ads1015: write config register only on change

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There is no point writing ADS1015_CFG_REG when configuration
didn't change. Avoid that.

Cc: Daniel Baluta <daniel.baluta@gmail.com>
Cc: Jonathan Cameron <jic23@kernel.org>
Signed-off-by: Ladislav Michl <ladis@linux-mips.org>
Reviewed-by: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
This commit is contained in:
Ladislav Michl 2017-08-24 10:25:51 +02:00 committed by Jonathan Cameron
parent 4e57562b48
commit d1c11dc27e
1 changed files with 9 additions and 10 deletions
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19
drivers/iio/adc/ti-ads1015.c
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@ -332,7 +332,7 @@ static int ads1015_set_power_state(struct ads1015_data *data, bool on)
static
int ads1015_get_adc_result(struct ads1015_data *data, int chan, int *val)
{
int ret, pga, dr, conv_time;
int ret, pga, dr, dr_old, conv_time;
unsigned int old, mask, cfg;
if (chan < 0 || chan >= ADS1015_CHANNELS)
@ -358,15 +358,14 @@ int ads1015_get_adc_result(struct ads1015_data *data, int chan, int *val)
}
cfg = (old & ~mask) | (cfg & mask);
ret = regmap_write(data->regmap, ADS1015_CFG_REG, cfg);
if (ret)
return ret;
if (old != cfg || data->conv_invalid) {
int dr_old = (old & ADS1015_CFG_DR_MASK) >>
ADS1015_CFG_DR_SHIFT;
if (old != cfg) {
ret = regmap_write(data->regmap, ADS1015_CFG_REG, cfg);
if (ret)
return ret;
data->conv_invalid = true;
}
if (data->conv_invalid) {
dr_old = (old & ADS1015_CFG_DR_MASK) >> ADS1015_CFG_DR_SHIFT;
conv_time = DIV_ROUND_UP(USEC_PER_SEC, data->data_rate[dr_old]);
conv_time += DIV_ROUND_UP(USEC_PER_SEC, data->data_rate[dr]);
usleep_range(conv_time, conv_time + 1);