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Commit d7203ad8 authored by Alison Schofield's avatar Alison Schofield Committed by Jonathan Cameron
Browse files

iio: adc: ad7791: claim direct mode when writing frequency 



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.

Refactor function to clarify look-up followed by lock sequence.

Signed-off-by: default avatarAlison Schofield <amsfield22@gmail.com>
Cc: Daniel Baluta <daniel.baluta@gmail.com>
Acked-by: default avatarLars-Peter Clausen <lars@metafoo.de>
Signed-off-by: default avatarJonathan Cameron <jic23@kernel.org>
parent afa81484

drivers/iio/adc/ad7791.c

+14 −22
Original line number Diff line number Diff line
@@ -272,30 +272,22 @@ 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)) {

	for (i = 0; i < ARRAY_SIZE(ad7791_sample_freq_avail); i++)

		if (sysfs_streq(ad7791_sample_freq_avail[i], buf))

			break;

	if (i == ARRAY_SIZE(ad7791_sample_freq_avail))

		return -EINVAL;



			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);

			ret = 0;

			break;

		}

	}

	ad_sd_write_reg(&st->sd, AD7791_REG_FILTER, sizeof(st->filter),

			st->filter);

	iio_device_release_direct_mode(indio_dev);



	return ret ? ret : len;

	return len;

}



static IIO_DEV_ATTR_SAMP_FREQ(S_IWUSR | S_IRUGO,