diff options
| author | Alison Schofield <amsfield22@gmail.com> | 2016-06-01 21:28:14 -0700 |
|---|---|---|
| committer | Jonathan Cameron <jic23@kernel.org> | 2016-06-03 13:01:14 +0100 |
| commit | afa814841c812cd1a36dbbb124542a487c2df5ee (patch) | |
| tree | cdb8d71bf49fb07b0404138c21a5ecd861e291b7 /drivers | |
| parent | 7c7e9dad7017ff5b5f0524ea6d85dcda3c62431e (diff) | |
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: Alison Schofield <amsfield22@gmail.com>
Cc: Daniel Baluta <daniel.baluta@gmail.com>
Acked-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/iio/adc/ad7793.c | 32 |
1 files changed, 13 insertions, 19 deletions
diff --git a/drivers/iio/adc/ad7793.c b/drivers/iio/adc/ad7793.c index 7b07bb651671..a43722fbf03a 100644 --- a/drivers/iio/adc/ad7793.c +++ b/drivers/iio/adc/ad7793.c @@ -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); - 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; - } + if (lval == st->chip_info->sample_freq_avail[i]) + break; + if (i == 16) + return -EINVAL; - return ret ? ret : len; + 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); + iio_device_release_direct_mode(indio_dev); + + return len; } static IIO_DEV_ATTR_SAMP_FREQ(S_IWUSR | S_IRUGO, |