On Tue, May 24, 2016 at 10:16 PM, Alison Schofield <amsfield22@xxxxxxxxx> wrote:
> Driver was checking for direct mode and trying to lock it, but
> left a gap where mode could change before the desired operation.
> Use iio_device_claim_direct_mode() to guarantee device stays in
> direct mode.
>
> Signed-off-by: Alison Schofield <amsfield22@xxxxxxxxx>
> Cc: Daniel Baluta <daniel.baluta@xxxxxxxxx>
Looks good to me. We could use an Acked-by from Lars here.
Acked-by: Daniel Baluta <daniel.baluta@xxxxxxxxx>
> ---
> drivers/iio/adc/ad7791.c | 15 ++++-----------
> 1 file changed, 4 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/iio/adc/ad7791.c b/drivers/iio/adc/ad7791.c
> index cf172d58..f7edacc 100644
> --- a/drivers/iio/adc/ad7791.c
> +++ b/drivers/iio/adc/ad7791.c
> @@ -272,24 +272,17 @@ static ssize_t ad7791_write_frequency(struct device *dev,
> struct ad7791_state *st = iio_priv(indio_dev);
> int i, ret;
>
> - mutex_lock(&indio_dev->mlock);
> - if (iio_buffer_enabled(indio_dev)) {
> - mutex_unlock(&indio_dev->mlock);
> - return -EBUSY;
> - }
> - mutex_unlock(&indio_dev->mlock);
> -
> - ret = -EINVAL;
> -
> for (i = 0; i < ARRAY_SIZE(ad7791_sample_freq_avail); i++) {
> if (sysfs_streq(ad7791_sample_freq_avail[i], buf)) {
>
> - mutex_lock(&indio_dev->mlock);
> + ret = iio_device_claim_direct_mode(indio_dev);
> + if (ret)
> + return ret;
> st->filter &= ~AD7791_FILTER_RATE_MASK;
> st->filter |= i;
> ad_sd_write_reg(&st->sd, AD7791_REG_FILTER,
> sizeof(st->filter), st->filter);
> - mutex_unlock(&indio_dev->mlock);
> + iio_device_release_direct_mode(indio_dev);
> ret = 0;
> break;
> }
> --
> 2.1.4
>
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