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iio:ad7791: Report scale as fractional value

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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>
This commit is contained in:
Lars-Peter Clausen 2013-09-28 10:31:00 +01:00 committed by Jonathan Cameron
parent d88c89db9a
commit 488a21827a
1 changed files with 10 additions and 8 deletions
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18
drivers/iio/adc/ad7791.c
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@ -202,7 +202,6 @@ static int ad7791_read_raw(struct iio_dev *indio_dev,
{ {
struct ad7791_state *st = iio_priv(indio_dev); struct ad7791_state *st = iio_priv(indio_dev);
bool unipolar = !!(st->mode & AD7791_MODE_UNIPOLAR); bool unipolar = !!(st->mode & AD7791_MODE_UNIPOLAR);
unsigned long long scale_pv;
switch (info) { switch (info) {
case IIO_CHAN_INFO_RAW: case IIO_CHAN_INFO_RAW:
@ -220,23 +219,26 @@ static int ad7791_read_raw(struct iio_dev *indio_dev,
case IIO_CHAN_INFO_SCALE: case IIO_CHAN_INFO_SCALE:
/* The monitor channel uses an internal reference. */ /* The monitor channel uses an internal reference. */
if (chan->address == AD7791_CH_AVDD_MONITOR) { 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 { } else {
int voltage_uv; int voltage_uv;
voltage_uv = regulator_get_voltage(st->reg); voltage_uv = regulator_get_voltage(st->reg);
if (voltage_uv < 0) if (voltage_uv < 0)
return voltage_uv; return voltage_uv;
scale_pv = (unsigned long long)voltage_uv * 1000000;
*val = voltage_uv / 1000;
} }
if (unipolar) if (unipolar)
scale_pv >>= chan->scan_type.realbits; *val2 = chan->scan_type.realbits;
else else
scale_pv >>= chan->scan_type.realbits - 1; *val2 = chan->scan_type.realbits - 1;
*val2 = do_div(scale_pv, 1000000000);
*val = scale_pv;
return IIO_VAL_INT_PLUS_NANO; return IIO_VAL_FRACTIONAL_LOG2;
} }
return -EINVAL; return -EINVAL;