Having two or more channels with the same positive scan_index field
makes no sense if the device supports buffering. Prevent this situation
by failing to register such a device.
Signed-off-by: Vlad Dogaru <vlad.dogaru@xxxxxxxxx>
Reviewed-by: Lars-Peter Clausen <lars@xxxxxxxxxx>
---
Changes since v4:
- actually include the check mentioned in v4, forgot to 'git add' it the first
time around :)
- reword description to mention that we only check devices that support
buffering.
Changes since v3:
- only check for duplicates if device supports buffering.
Changes since v2:
- rebase to latest togreg branch.
Changes since v1:
- remove redundant check for scan_index < 0 in the inner loop.
drivers/iio/industrialio-core.c | 27 +++++++++++++++++++++++++++
1 file changed, 27 insertions(+)
diff --git a/drivers/iio/industrialio-core.c b/drivers/iio/industrialio-core.c
index ee442ee..cc80c59 100644
--- a/drivers/iio/industrialio-core.c
+++ b/drivers/iio/industrialio-core.c
@@ -1135,6 +1135,29 @@ static const struct file_operations iio_buffer_fileops = {
.compat_ioctl = iio_ioctl,
};
+static int iio_check_unique_scan_index(struct iio_dev *indio_dev)
+{
+ int i, j;
+ const struct iio_chan_spec *channels = indio_dev->channels;
+
+ if (!(indio_dev->modes & INDIO_ALL_BUFFER_MODES))
+ return 0;
+
+ for (i = 0; i < indio_dev->num_channels - 1; i++) {
+ if (channels[i].scan_index < 0)
+ continue;
+ for (j = i + 1; j < indio_dev->num_channels; j++)
+ if (channels[i].scan_index == channels[j].scan_index) {
+ dev_err(&indio_dev->dev,
+ "Duplicate scan index %d\n",
+ channels[i].scan_index);
+ return -EINVAL;
+ }
+ }
+
+ return 0;
+}
+
static const struct iio_buffer_setup_ops noop_ring_setup_ops;
/**
@@ -1149,6 +1172,10 @@ int iio_device_register(struct iio_dev *indio_dev)
if (!indio_dev->dev.of_node && indio_dev->dev.parent)
indio_dev->dev.of_node = indio_dev->dev.parent->of_node;
+ ret = iio_check_unique_scan_index(indio_dev);
+ if (ret < 0)
+ return ret;
+
/* configure elements for the chrdev */
indio_dev->dev.devt = MKDEV(MAJOR(iio_devt), indio_dev->id);
--
1.9.1
--
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