xref: /freebsd/sys/contrib/device-tree/Bindings/input/touchscreen/resistive-adc-touch.txt (revision c66ec88fed842fbaad62c30d510644ceb7bd2d71)
1*c66ec88fSEmmanuel VadotGeneric resistive touchscreen ADC
2*c66ec88fSEmmanuel Vadot
3*c66ec88fSEmmanuel VadotRequired properties:
4*c66ec88fSEmmanuel Vadot
5*c66ec88fSEmmanuel Vadot - compatible: must be "resistive-adc-touch"
6*c66ec88fSEmmanuel VadotThe device must be connected to an ADC device that provides channels for
7*c66ec88fSEmmanuel Vadotposition measurement and optional pressure.
8*c66ec88fSEmmanuel VadotRefer to ../iio/iio-bindings.txt for details
9*c66ec88fSEmmanuel Vadot - iio-channels: must have at least two channels connected to an ADC device.
10*c66ec88fSEmmanuel VadotThese should correspond to the channels exposed by the ADC device and should
11*c66ec88fSEmmanuel Vadothave the right index as the ADC device registers them. These channels
12*c66ec88fSEmmanuel Vadotrepresent the relative position on the "x" and "y" axes.
13*c66ec88fSEmmanuel Vadot - iio-channel-names: must have all the channels' names. Mandatory channels
14*c66ec88fSEmmanuel Vadotare "x" and "y".
15*c66ec88fSEmmanuel Vadot
16*c66ec88fSEmmanuel VadotOptional properties:
17*c66ec88fSEmmanuel Vadot - iio-channels: The third channel named "pressure" is optional and can be
18*c66ec88fSEmmanuel Vadotused if the ADC device also measures pressure besides position.
19*c66ec88fSEmmanuel VadotIf this channel is missing, pressure will be ignored and the touchscreen
20*c66ec88fSEmmanuel Vadotwill only report position.
21*c66ec88fSEmmanuel Vadot - iio-channel-names: optional channel named "pressure".
22*c66ec88fSEmmanuel Vadot
23*c66ec88fSEmmanuel VadotExample:
24*c66ec88fSEmmanuel Vadot
25*c66ec88fSEmmanuel Vadot	resistive_touch: resistive_touch {
26*c66ec88fSEmmanuel Vadot		compatible = "resistive-adc-touch";
27*c66ec88fSEmmanuel Vadot		touchscreen-min-pressure = <50000>;
28*c66ec88fSEmmanuel Vadot		io-channels = <&adc 24>, <&adc 25>, <&adc 26>;
29*c66ec88fSEmmanuel Vadot		io-channel-names = "x", "y", "pressure";
30*c66ec88fSEmmanuel Vadot	};
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