diff options
| author | Lars-Peter Clausen <lars@metafoo.de> | 2013-09-28 10:31:00 +0100 |
|---|---|---|
| committer | Jonathan Cameron <jic23@kernel.org> | 2013-10-01 16:19:11 +0100 |
| commit | 3f83dae88422992140b6125ab866cdec9fd7b3b6 (patch) | |
| tree | 1b3b8194819cd975eb6e63c3ab08f80e914ac767 /drivers/iio/dac | |
| parent | ae76751f67110f497848afd71d06a0b6bb4a7c89 (diff) | |
iio:ad5764: Report scale as fractional value
Move the complexity of calculating the fixed point scale to the core.
Also fix a off by one error in the comment describing the transfer function.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
Diffstat (limited to 'drivers/iio/dac')
| -rw-r--r-- | drivers/iio/dac/ad5764.c | 10 |
1 files changed, 4 insertions, 6 deletions
diff --git a/drivers/iio/dac/ad5764.c b/drivers/iio/dac/ad5764.c index df7e028d9db5..a8ff5b2ed13e 100644 --- a/drivers/iio/dac/ad5764.c +++ b/drivers/iio/dac/ad5764.c @@ -217,7 +217,6 @@ static int ad5764_read_raw(struct iio_dev *indio_dev, struct iio_chan_spec const *chan, int *val, int *val2, long info) { struct ad5764_state *st = iio_priv(indio_dev); - unsigned long scale_uv; unsigned int reg; int vref; int ret; @@ -245,15 +244,14 @@ static int ad5764_read_raw(struct iio_dev *indio_dev, *val = sign_extend32(*val, 5); return IIO_VAL_INT; case IIO_CHAN_INFO_SCALE: - /* vout = 4 * vref + ((dac_code / 65535) - 0.5) */ + /* vout = 4 * vref + ((dac_code / 65536) - 0.5) */ vref = ad5764_get_channel_vref(st, chan->channel); if (vref < 0) return vref; - scale_uv = (vref * 4 * 100) >> chan->scan_type.realbits; - *val = scale_uv / 100000; - *val2 = (scale_uv % 100000) * 10; - return IIO_VAL_INT_PLUS_MICRO; + *val = vref * 4 / 1000; + *val2 = chan->scan_type.realbits; + return IIO_VAL_FRACTIONAL_LOG2; case IIO_CHAN_INFO_OFFSET: *val = -(1 << chan->scan_type.realbits) / 2; return IIO_VAL_INT; |