For detachable or lock-able joysticks the ADC lanes might
be biased to GND or AVDD when the joystick is detached/locked.
One such kind of joystick is found in the Ritmix RZX-50 handheld.
The joystick is non-detachable, although ADC lane biased to power
supply when the "Hold" switch is activated.
To avoid reporting old/broken measurements valid-range is introduced.
When measured value is outside valid-range the driver reports
safe center position for corresponding axis.
Siarhei Volkau (2):
dt-bindings: adc-joystick: add valid-range
Input: adc-joystick - add detachable devices support
.../bindings/input/adc-joystick.yaml | 62 +++++++++++++++++++
drivers/input/joystick/adc-joystick.c | 58 ++++++++++++++++-
2 files changed, 119 insertions(+), 1 deletion(-)
--
2.36.1
Hi Siarhei,
Le lun. 31 oct. 2022 ? 22:01:57 +0300, Siarhei Volkau
<[email protected]> a ?crit :
> For detachable or lock-able joysticks the ADC lanes might
> be biased to GND or AVDD when the joystick is detached/locked.
>
> One such kind of joystick is found in the Ritmix RZX-50 handheld.
> The joystick is non-detachable, although ADC lane biased to power
> supply when the "Hold" switch is activated.
But the RZX-50 has no joystick...
Or is the d-pad actually wired to the ADC instead of GPIOs?
> To avoid reporting old/broken measurements valid-range is introduced.
> When measured value is outside valid-range the driver reports
> safe center position for corresponding axis.
First of all, you already have a "valid range", it is called
"abs-range"; no need for a new one.
Then, the driver has no business doing events filtering. Notice that
when you activate the "hold" button and your joystick values go way
off-range, you still get input events in userspace: that's because the
kernel is not responsible for enforcing the deadzone, the userspace is.
In your case, you need to update your userspace applications/libraries
so that when the joystick values are way off-range, the assumed
position is the center.
Cheers,
-Paul
вс, 6 нояб. 2022 г. в 02:39, Paul Cercueil <[email protected]>:
>
> Hi Siarhei,
>
> Le lun. 31 oct. 2022 à 22:01:57 +0300, Siarhei Volkau
> <[email protected]> a écrit :
> > For detachable or lock-able joysticks the ADC lanes might
> > be biased to GND or AVDD when the joystick is detached/locked.
> >
> > One such kind of joystick is found in the Ritmix RZX-50 handheld.
> > The joystick is non-detachable, although ADC lane biased to power
> > supply when the "Hold" switch is activated.
>
> But the RZX-50 has no joystick...
Well, actually there's two versions in the wild (google "RZX-50 pictures"):
- with analog joystick and speakers on the back side
- without the joystick and speakers on the front side
I have only the first one at the moment, but I'm looking for another one.
> Or is the d-pad actually wired to the ADC instead of GPIOs?
The D-Pad is another kind of pain there - it's a part of the matrix-keypad
but the pad's row line is shared with the LCD HSYNC signal.
> > To avoid reporting old/broken measurements valid-range is introduced.
> > When measured value is outside valid-range the driver reports
> > safe center position for corresponding axis.
>
> First of all, you already have a "valid range", it is called
> "abs-range"; no need for a new one.
>
> Then, the driver has no business doing events filtering. Notice that
> when you activate the "hold" button and your joystick values go way
> off-range, you still get input events in userspace: that's because the
> kernel is not responsible for enforcing the deadzone, the userspace is.
>
> In your case, you need to update your userspace applications/libraries
> so that when the joystick values are way off-range, the assumed
> position is the center.
Many userspace apps use SDL library to handle joystick input, the SDL
unfortunately hides the fact that the joystick position is out of range -
it does normalization and clamping of the abs-range to an int16_t range.
I see two approaches to do that in userspace:
1. Make a quirk in the SDL library, which affects many types of joysticks
and lead to a fragmentation (special userspace apps for every hardware
isn't the right way in my opinion).
2. Make a special filter app which will filter out invalid joystick events and
route rest to the /dev/input/uinput. Not sure how to hide the real joystick
device from libraries like SDL then.
Both of them don't look like a "silver bullet", however feasible.
>
> Cheers,
> -Paul
>
>
Thank you.
> Not sure how to hide the real joystick device from libraries like SDL
Got it, EVIOCGRAB ioctl shall do the job.
Thank you all !
BR,
Siarhei