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Commit cd36835b authored by Liam Beguin's avatar Liam Beguin Committed by Greg Kroah-Hartman
Browse files

iio: inkern: make a best effort on offset calculation 



commit ca85123354e1a65a22170286387b4791997fe864 upstream.

iio_convert_raw_to_processed_unlocked() assumes the offset is an
integer. Make a best effort to get a valid offset value for fractional
cases without breaking implicit truncations.

Fixes: 48e44ce0 ("iio:inkern: Add function to read the processed value")
Signed-off-by: default avatarLiam Beguin <liambeguin@gmail.com>
Reviewed-by: default avatarPeter Rosin <peda@axentia.se>
Reviewed-by: default avatarAndy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20220108205319.2046348-4-liambeguin@gmail.com


Cc: <Stable@vger.kernel.org>
Signed-off-by: default avatarJonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 45bfe8d8

drivers/iio/inkern.c

+27 −5
Original line number Diff line number Diff line
@@ -591,13 +591,35 @@ EXPORT_SYMBOL_GPL(iio_read_channel_average_raw); 
static int iio_convert_raw_to_processed_unlocked(struct iio_channel *chan,

	int raw, int *processed, unsigned int scale)

{

	int scale_type, scale_val, scale_val2, offset;

	int scale_type, scale_val, scale_val2;

	int offset_type, offset_val, offset_val2;

	s64 raw64 = raw;

	int ret;



	ret = iio_channel_read(chan, &offset, NULL, IIO_CHAN_INFO_OFFSET);

	if (ret >= 0)

		raw64 += offset;

	offset_type = iio_channel_read(chan, &offset_val, &offset_val2,

				       IIO_CHAN_INFO_OFFSET);

	if (offset_type >= 0) {

		switch (offset_type) {

		case IIO_VAL_INT:

			break;

		case IIO_VAL_INT_PLUS_MICRO:

		case IIO_VAL_INT_PLUS_NANO:

			/*

			 * Both IIO_VAL_INT_PLUS_MICRO and IIO_VAL_INT_PLUS_NANO

			 * implicitely truncate the offset to it's integer form.

			 */

			break;

		case IIO_VAL_FRACTIONAL:

			offset_val /= offset_val2;

			break;

		case IIO_VAL_FRACTIONAL_LOG2:

			offset_val >>= offset_val2;

			break;

		default:

			return -EINVAL;

		}



		raw64 += offset_val;

	}



	scale_type = iio_channel_read(chan, &scale_val, &scale_val2,

					IIO_CHAN_INFO_SCALE);