From d1c11dc27e3282e787406290ead5926bb7bb4579 Mon Sep 17 00:00:00 2001 From: Ladislav Michl Date: Thu, 24 Aug 2017 10:25:51 +0200 Subject: [PATCH] iio: adc: ti-ads1015: write config register only on change There is no point writing ADS1015_CFG_REG when configuration didn't change. Avoid that. Cc: Daniel Baluta Cc: Jonathan Cameron Signed-off-by: Ladislav Michl Reviewed-by: Akinobu Mita Signed-off-by: Jonathan Cameron --- drivers/iio/adc/ti-ads1015.c | 19 +++++++++---------- 1 file changed, 9 insertions(+), 10 deletions(-) diff --git a/drivers/iio/adc/ti-ads1015.c b/drivers/iio/adc/ti-ads1015.c index 731ec38..7503ea5 100644 --- a/drivers/iio/adc/ti-ads1015.c +++ b/drivers/iio/adc/ti-ads1015.c @@ -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); -- 2.7.4