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Commit 8f5d8727 authored by Vlad Dogaru's avatar Vlad Dogaru Committed by Jonathan Cameron
Browse files

iio: ensure scan index is unique at device register 



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: default avatarVlad Dogaru <vlad.dogaru@intel.com>
Reviewed-by: default avatarLars-Peter Clausen <lars@metafoo.de>
Signed-off-by: default avatarJonathan Cameron <jic23@kernel.org>
parent c22d2672

drivers/iio/industrialio-core.c

+27 −0
Original line number Diff line number Diff line
@@ -1134,6 +1134,29 @@ 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;



/**
@@ -1148,6 +1171,10 @@ 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);