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|
{ ... }:
{
hardware.deviceTree = {
overlays = [
{
name = "ads7846-overlay";
# taken from raspberry-pi kernel tree:
# https://github.com/raspberrypi/linux/blob/rpi-6.6.y/arch/arm/boot/dts/overlays/ads7846-overlay.dts
dtsText = ''
/*
* Generic Device Tree overlay for the ADS7846 touch controller
*
*/
/dts-v1/;
/plugin/;
/ {
compatible = "brcm,bcm2835";
fragment@0 {
target = <&spi0>;
__overlay__ {
status = "okay";
};
};
fragment@1 {
target = <&spidev0>;
__overlay__ {
status = "disabled";
};
};
fragment@2 {
target = <&spidev1>;
__overlay__ {
status = "disabled";
};
};
fragment@3 {
target = <&gpio>;
__overlay__ {
ads7846_pins: ads7846_pins {
brcm,pins = <255>; /* illegal default value */
brcm,function = <0>; /* in */
brcm,pull = <0>; /* none */
};
};
};
fragment@4 {
target = <&spi0>;
__overlay__ {
/* needed to avoid dtc warning */
#address-cells = <1>;
#size-cells = <0>;
ads7846: ads7846@1 {
compatible = "ti,ads7846";
reg = <1>;
pinctrl-names = "default";
pinctrl-0 = <&ads7846_pins>;
spi-max-frequency = <2000000>;
interrupts = <255 2>; /* high-to-low edge triggered */
interrupt-parent = <&gpio>;
pendown-gpio = <&gpio 255 1>;
/* driver defaults */
ti,x-min = /bits/ 16 <0>;
ti,y-min = /bits/ 16 <0>;
ti,x-max = /bits/ 16 <0x0FFF>;
ti,y-max = /bits/ 16 <0x0FFF>;
ti,pressure-min = /bits/ 16 <0>;
ti,pressure-max = /bits/ 16 <0xFFFF>;
ti,x-plate-ohms = /bits/ 16 <400>;
};
};
};
__overrides__ {
cs = <&ads7846>,"reg:0";
speed = <&ads7846>,"spi-max-frequency:0";
penirq = <&ads7846_pins>,"brcm,pins:0", /* REQUIRED */
<&ads7846>,"interrupts:0",
<&ads7846>,"pendown-gpio:4";
penirq_pull = <&ads7846_pins>,"brcm,pull:0";
swapxy = <&ads7846>,"ti,swap-xy?";
xmin = <&ads7846>,"ti,x-min;0";
ymin = <&ads7846>,"ti,y-min;0";
xmax = <&ads7846>,"ti,x-max;0";
ymax = <&ads7846>,"ti,y-max;0";
pmin = <&ads7846>,"ti,pressure-min;0";
pmax = <&ads7846>,"ti,pressure-max;0";
xohms = <&ads7846>,"ti,x-plate-ohms;0";
};
};
'';
}
];
};
}
|
