From afa814841c812cd1a36dbbb124542a487c2df5ee Mon Sep 17 00:00:00 2001 From: Alison Schofield Date: Wed, 1 Jun 2016 21:28:14 -0700 Subject: [PATCH] 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 Cc: Daniel Baluta Acked-by: Lars-Peter Clausen Signed-off-by: Jonathan Cameron --- drivers/iio/adc/ad7793.c | 32 +++++++++++++------------------- 1 file 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, -- 2.20.1