On 30/08/16 07:27, Martin Hundebøll wrote:
> The Analog Devices DAC chips supported by the ad5456 driver ignore
> between 0 and 6 of the least significant bits, and thus the written raw
> value is shifted accordingly before being cached and written.
>
> Since the shifted value is cached, it is returned to the user in
> ad5446_read_raw(), which might be confusing to the user (at least it was
> for me).
>
> Instead store the unshifted value and do the shifting when needed (i.e.
> when writing data and disabling powerdown mode).
>
> Signed-off-by: Martin Hundebøll <mnhu@xxxxxxxxx>
Lars?
Looks right to me, could you just sanity check this.
Stable material I think.
Jonathan
> ---
> drivers/iio/dac/ad5446.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/iio/dac/ad5446.c b/drivers/iio/dac/ad5446.c
> index 46bb62a..8d172d7 100644
> --- a/drivers/iio/dac/ad5446.c
> +++ b/drivers/iio/dac/ad5446.c
> @@ -118,7 +118,7 @@ static ssize_t ad5446_write_dac_powerdown(struct iio_dev *indio_dev,
> shift = chan->scan_type.realbits + chan->scan_type.shift;
> val = st->pwr_down_mode << shift;
> } else {
> - val = st->cached_val;
> + val = st->cached_val << chan->scan_type.shift;
> }
>
> ret = st->chip_info->write(st, val);
> @@ -195,9 +195,9 @@ static int ad5446_write_raw(struct iio_dev *indio_dev,
> if (val >= (1 << chan->scan_type.realbits) || val < 0)
> return -EINVAL;
>
> - val <<= chan->scan_type.shift;
> mutex_lock(&indio_dev->mlock);
> st->cached_val = val;
> + val <<= chan->scan_type.shift;
> if (!st->pwr_down)
> ret = st->chip_info->write(st, val);
> mutex_unlock(&indio_dev->mlock);
>
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