[PATCH 3/7] iio: adc: ad7793: claim direct mode when writing frequency

[Alison Schofield]

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>
---
 drivers/iio/adc/ad7793.c | 13 ++++---------
 1 file changed, 4 insertions(+), 9 deletions(-)

diff --git a/drivers/iio/adc/ad7793.c b/drivers/iio/adc/ad7793.c
index 7b07bb6..3f41cd8 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;
@@ -387,12 +380,14 @@ static ssize_t ad7793_write_frequency(struct device *dev,
 
 	for (i = 0; i < 16; i++)
 		if (lval == st->chip_info->sample_freq_avail[i]) {
-			mutex_lock(&indio_dev->mlock);
+			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);
+			iio_device_release_direct_mode(indio_dev);
 			ret = 0;
 		}
 
-- 
2.1.4