Re: [PATCH v7 5/6] iio: ABI: Add partial quaternion modifier

[Jonathan Cameron <jic23@kernel.org>]

> diff --git a/include/uapi/linux/iio/types.h b/include/uapi/linux/iio/types.h
> index 6d269b844271..c80ef7c1ed12 100644
> --- a/include/uapi/linux/iio/types.h
> +++ b/include/uapi/linux/iio/types.h
> @@ -77,6 +77,7 @@ enum iio_modifier {
>  	IIO_MOD_LIGHT_GREEN,
>  	IIO_MOD_LIGHT_BLUE,
>  	IIO_MOD_QUATERNION,
> +	IIO_MOD_PARTIAL_QUATERNION,
I nearly missed this.  This is a userspace header for a reason. The ABI is
fixed so we can't change the enumeration. We can only add to the end.

Good thing the discussion on the _ came up and made me wonder why the name
above was in near one with underscores!



>  	IIO_MOD_TEMP_AMBIENT,
>  	IIO_MOD_TEMP_OBJECT,
>  	IIO_MOD_NORTH_MAGN,
All userspace code using these would now be broken.