iio: Add channel for Position Relative

Add new channel type for relative position on a pad.

These type of analog sensor offers the position of a pen
on a touchpad, and is represented as a voltage, which can be
converted to a position on X and Y axis on the pad.
The channel will hand the relative position on the pad in both directions.

The channel can then be consumed by a touchscreen driver or
read as-is for a raw indication of the touchpen on a touchpad.

Signed-off-by: Eugen Hristev <eugen.hristev@microchip.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/include/uapi/linux/iio/types.h b/include/uapi/linux/iio/types.h
index 4213cdf88e3c..033c7d28924e 100644
--- a/include/uapi/linux/iio/types.h
+++ b/include/uapi/linux/iio/types.h
@@ -44,6 +44,7 @@ enum iio_chan_type {
         IIO_COUNT,
         IIO_INDEX,
         IIO_GRAVITY,
+        IIO_POSITIONRELATIVE,
 };
 
 enum iio_modifier {