From fe895ac88b9fbdf2026f0bfd56c82747bb9d7c48 Mon Sep 17 00:00:00 2001 From: Ladislav Michl Date: Fri, 25 Aug 2017 07:39:16 +0200 Subject: iio: adc: ti-ads1015: add 10% to conversion wait time MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit As user's guide "ADS1015EVM, ADS1115EVM, ADS1015EVM-PDK, ADS1115EVM-PDK User Guide (Rev. B)" (http://www.ti.com/lit/ug/sbau157b/sbau157b.pdf) states at page 16: "Note that both the ADS1115 and ADS1015 have internal clocks with a ±10% accuracy. If performing FFT tests, frequencies may appear to be incorrect as a result of this tolerance range.", add those 10% to converion wait time. 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 | 1 + 1 file changed, 1 insertion(+) (limited to 'drivers/iio/adc') diff --git a/drivers/iio/adc/ti-ads1015.c b/drivers/iio/adc/ti-ads1015.c index 7503ea56b781..3e9719e8cf3b 100644 --- a/drivers/iio/adc/ti-ads1015.c +++ b/drivers/iio/adc/ti-ads1015.c @@ -368,6 +368,7 @@ int ads1015_get_adc_result(struct ads1015_data *data, int chan, int *val) 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]); + conv_time += conv_time / 10; /* 10% internal clock inaccuracy */ usleep_range(conv_time, conv_time + 1); data->conv_invalid = false; } -- cgit v1.2.3