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Commit afa81484 authored by Alison Schofield's avatar Alison Schofield Committed by Jonathan Cameron
Browse files

iio: adc: ad7793: 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 7c7e9dad

drivers/iio/adc/ad7793.c

+13 −19
Original line number Diff line number Diff line
@@ -369,13 +369,6 @@ static ssize_t ad7793_write_frequency(struct device *dev, 
	long lval;

	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 = kstrtol(buf, 10, &lval);

	if (ret)

		return ret;
@@ -383,20 +376,21 @@ static ssize_t ad7793_write_frequency(struct device *dev, 
	if (lval == 0)

		return -EINVAL;



	ret = -EINVAL;



	for (i = 0; i < 16; i++)

		if (lval == st->chip_info->sample_freq_avail[i]) {

			mutex_lock(&indio_dev->mlock);

		if (lval == st->chip_info->sample_freq_avail[i])

			break;

	if (i == 16)

		return -EINVAL;



	ret = iio_device_claim_direct_mode(indio_dev);

	if (ret)

		return ret;

	st->mode &= ~AD7793_MODE_RATE(-1);

	st->mode |= AD7793_MODE_RATE(i);

			ad_sd_write_reg(&st->sd, AD7793_REG_MODE,

					 sizeof(st->mode), st->mode);

			mutex_unlock(&indio_dev->mlock);

			ret = 0;

		}

	ad_sd_write_reg(&st->sd, AD7793_REG_MODE, sizeof(st->mode), st->mode);

	iio_device_release_direct_mode(indio_dev);



	return ret ? ret : len;

	return len;

}



static IIO_DEV_ATTR_SAMP_FREQ(S_IWUSR | S_IRUGO,