On Fri, Dec 15, 2023 at 12:19:51PM +0100, Artur Rojek wrote: > On 2023-12-15 03:40, Chris Morgan wrote: > > From: Chris Morgan <macromorgan@xxxxxxxxxxx> > > > > uinput refuses to work with abs devices where the min value is greater > > than the max value. uinput_validate_absinfo() returns -EINVAL if this > > is the case and prevents using uinput on such a device. Since uinput > > has worked this way since at least kernel 2.6 (or prior) I presume that > > this is the correct way of doing things, and that this documentation > > needs to be clarified that min must always be less than max. > > > > uinput is used in my use case to bind together adc-joystick devices > > with gpio-keys devices to create a single unified gamepad for > > userspace. > > > > Note that there are several boards that will need to be corrected, > > all but a few of them I maintain. Submitting as an RFC for now to get > > comments from the input team and the original author in case there is > > something I am missing. > > > > Fixes: 7956b0d4694f ("dt-bindings: input: Add docs for ADC driven > > joystick") > > > > Signed-off-by: Chris Morgan <macromorgan@xxxxxxxxxxx> > > --- > > Documentation/devicetree/bindings/input/adc-joystick.yaml | 5 +++-- > > 1 file changed, 3 insertions(+), 2 deletions(-) > > > > diff --git a/Documentation/devicetree/bindings/input/adc-joystick.yaml > > b/Documentation/devicetree/bindings/input/adc-joystick.yaml > > index 6c244d66f8ce..8f5cdd5ef190 100644 > > --- a/Documentation/devicetree/bindings/input/adc-joystick.yaml > > +++ b/Documentation/devicetree/bindings/input/adc-joystick.yaml > > @@ -73,8 +73,9 @@ patternProperties: > > description: > > > Minimum and maximum values produced by the axis. > > For an ABS_X axis this will be the left-most and right-most > > - inclination of the joystick. If min > max, it is left to > > userspace to > > - treat the axis as inverted. > > + inclination of the joystick. The axis must always be > > expressed as > > + min < max, if the axis is inverted it is left to userspace to > > handle > > + the inversion. > > Hi Chris, > > Device Tree is supposed to depict the actual state of the hardware. > I worded the adc-joytick's adc-range property specifically, so that it > covers a case of GCW Zero hardware [1], which has a joystick, where the > ABS_X axis reports increasing values for the left-wards inclination of > the joystick, and decreasing values for the right-wards inclination. You > are saying that there are even more boards that need to be corrected - > those are all situations, where DT depicts the actual behavior of the > hardware. > What you are trying to do is change hardware description, because of how > a driver in an OS works. You should instead fix behavior of said driver, > even if nobody stumbled upon that issue since 2.6 :) We fixed libSDL [2] > for the same reason. > > Cheers, > Artur > > PS. cc'd Paul to the conversation. > > [1] https://github.com/OpenDingux/linux/blob/jz-6.1/arch/mips/boot/dts/ingenic/gcw0.dts#L273C12-L273C12 > [2] https://github.com/libsdl-org/SDL-1.2/commit/46806790ad043 Thank you. Okay, I'll update uinput instead to drop checks for min > max, since that's valid/allowed. Chris > > > This property is interpreted as two signed 32 bit values. > > > > abs-fuzz: >