From d7203ad864db0b34f0e106ec0659890c4e58c143 Mon Sep 17 00:00:00 2001
From: Alison Schofield <amsfield22@gmail.com>
Date: Tue, 31 May 2016 21:35:49 -0700
Subject: [PATCH] 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: 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>
---
drivers/iio/adc/ad7791.c | 36 ++++++++++++++----------------------
1 file changed, 14 insertions(+), 22 deletions(-)
diff --git a/drivers/iio/adc/ad7791.c b/drivers/iio/adc/ad7791.c
index cf172d58cd44c..1dfe6410c64cb 100644
--- a/drivers/iio/adc/ad7791.c
+++ b/drivers/iio/adc/ad7791.c
@@ -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)) {
-
- mutex_lock(&indio_dev->mlock);
- 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;
+ 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;
+
+ 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);
+ iio_device_release_direct_mode(indio_dev);
- return ret ? ret : len;
+ return len;
}
static IIO_DEV_ATTR_SAMP_FREQ(S_IWUSR | S_IRUGO,
--
GitLab