On Mon, 23 Apr 2018 00:03:03 +0200
David Veenstra <davidjulianveenstra@xxxxxxxxx> wrote:
> The manual states that the data is contained in the upper 12 bits
> of the 16 bits read by spi. The code that extracts these 12 bits
> is correct for both be and le machines, but this is not clear
> from a first glance.
>
> To improve readability the relevant expressions are replaced
> with equivalent expressions that use be16_to_cpup.
>
> Signed-off-by: David Veenstra <davidjulianveenstra@xxxxxxxxx>
Looks good to me.
Applied to the togreg branch of iio.git and pushed out as testing
for the autobuilders to play with it.
Thanks,
Jonathan
> ---
> Changes in v3:
> - change type of rx to __be16.
> - remove unneeded variable vel.
> - remove unneeded type cast to s16 (patch line 79).
>
> drivers/staging/iio/resolver/ad2s1200.c | 11 ++++-------
> 1 file changed, 4 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/staging/iio/resolver/ad2s1200.c b/drivers/staging/iio/resolver/ad2s1200.c
> index 17d65cb437fd..998f458dc1bd 100644
> --- a/drivers/staging/iio/resolver/ad2s1200.c
> +++ b/drivers/staging/iio/resolver/ad2s1200.c
> @@ -47,7 +47,7 @@ struct ad2s1200_state {
> struct spi_device *sdev;
> int sample;
> int rdvel;
> - u8 rx[2] ____cacheline_aligned;
> + __be16 rx ____cacheline_aligned;
> };
>
> static int ad2s1200_read_raw(struct iio_dev *indio_dev,
> @@ -58,7 +58,6 @@ static int ad2s1200_read_raw(struct iio_dev *indio_dev,
> {
> struct ad2s1200_state *st = iio_priv(indio_dev);
> int ret = 0;
> - s16 vel;
>
> mutex_lock(&st->lock);
> gpio_set_value(st->sample, 0);
> @@ -68,7 +67,7 @@ static int ad2s1200_read_raw(struct iio_dev *indio_dev,
> gpio_set_value(st->sample, 1);
> gpio_set_value(st->rdvel, !!(chan->type == IIO_ANGL));
>
> - ret = spi_read(st->sdev, st->rx, 2);
> + ret = spi_read(st->sdev, &st->rx, 2);
> if (ret < 0) {
> mutex_unlock(&st->lock);
> return ret;
> @@ -76,12 +75,10 @@ static int ad2s1200_read_raw(struct iio_dev *indio_dev,
>
> switch (chan->type) {
> case IIO_ANGL:
> - *val = (((u16)(st->rx[0])) << 4) | ((st->rx[1] & 0xF0) >> 4);
> + *val = be16_to_cpup(&st->rx) >> 4;
> break;
> case IIO_ANGL_VEL:
> - vel = (((s16)(st->rx[0])) << 4) | ((st->rx[1] & 0xF0) >> 4);
> - vel = sign_extend32(vel, 11);
> - *val = vel;
> + *val = sign_extend32(be16_to_cpup(&st->rx) >> 4, 11);
> break;
> default:
> mutex_unlock(&st->lock);
--
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