diff options
| author | Lars-Peter Clausen <lars@metafoo.de> | 2013-09-28 13:31:00 +0400 |
|---|---|---|
| committer | Jonathan Cameron <jic23@kernel.org> | 2013-10-01 19:19:12 +0400 |
| commit | 488a21827a257b735571468632e9f677b13bdddd (patch) | |
| tree | 2ddaf1b0bf51411bfb9fa37ed1bbc8160792c208 /drivers/iio/adc/ad7791.c | |
| parent | d88c89db9a7550c2ed6551f73b6702faee190434 (diff) | |
| download | linux-488a21827a257b735571468632e9f677b13bdddd.tar.xz | |
iio:ad7791: Report scale as fractional value
Move the complexity of calculating the fixed point scale to the core.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
Diffstat (limited to 'drivers/iio/adc/ad7791.c')
| -rw-r--r-- | drivers/iio/adc/ad7791.c | 18 |
1 files changed, 10 insertions, 8 deletions
diff --git a/drivers/iio/adc/ad7791.c b/drivers/iio/adc/ad7791.c index c20203577d2d..c19f8fd1b4b7 100644 --- a/drivers/iio/adc/ad7791.c +++ b/drivers/iio/adc/ad7791.c @@ -202,7 +202,6 @@ static int ad7791_read_raw(struct iio_dev *indio_dev, { struct ad7791_state *st = iio_priv(indio_dev); bool unipolar = !!(st->mode & AD7791_MODE_UNIPOLAR); - unsigned long long scale_pv; switch (info) { case IIO_CHAN_INFO_RAW: @@ -220,23 +219,26 @@ static int ad7791_read_raw(struct iio_dev *indio_dev, case IIO_CHAN_INFO_SCALE: /* The monitor channel uses an internal reference. */ if (chan->address == AD7791_CH_AVDD_MONITOR) { - scale_pv = 5850000000000ULL; + /* + * The signal is attenuated by a factor of 5 and + * compared against a 1.17V internal reference. + */ + *val = 1170 * 5; } else { int voltage_uv; voltage_uv = regulator_get_voltage(st->reg); if (voltage_uv < 0) return voltage_uv; - scale_pv = (unsigned long long)voltage_uv * 1000000; + + *val = voltage_uv / 1000; } if (unipolar) - scale_pv >>= chan->scan_type.realbits; + *val2 = chan->scan_type.realbits; else - scale_pv >>= chan->scan_type.realbits - 1; - *val2 = do_div(scale_pv, 1000000000); - *val = scale_pv; + *val2 = chan->scan_type.realbits - 1; - return IIO_VAL_INT_PLUS_NANO; + return IIO_VAL_FRACTIONAL_LOG2; } return -EINVAL; |