On 09/28/13 10:31, Lars-Peter Clausen wrote:
> 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@xxxxxxxxxx>
Applied to the togreg branch of iio.git
Thanks
> ---
> drivers/iio/dac/ad5764.c | 10 ++++------
> 1 file changed, 4 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/iio/dac/ad5764.c b/drivers/iio/dac/ad5764.c
> index df7e028..a8ff5b2 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;
>
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