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nixos-hardware/raspberry-pi/4/i2c.nix

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1.3 KiB
Nix

{ config, lib, pkgs, ... }:
let
cfg = config.hardware.raspberry-pi."4";
simple-overlay = { target, status }: {
name = "${target}-${status}-overlay";
dtsText = ''
/dts-v1/;
/plugin/;
/ {
compatible = "brcm,bcm2711";
fragment@0 {
target = <&${target}>;
__overlay__ {
status = "${status}";
};
};
};
'';
};
in
{
options.hardware.raspberry-pi."4" = {
i2c0.enable = lib.mkEnableOption ''
Turn on the VideoCore I2C bus (maps to /dev/i2c-22) and enable access from the i2c group.
After a reboot, i2c-tools (e.g. i2cdetect -F 22) should work for root or any user in i2c.
'';
i2c1.enable = lib.mkEnableOption ''
Turn on the ARM I2C bus (/dev/i2c-1 on GPIO pins 3 and 5) and enable access from the i2c group.
After a reboot, i2c-tools (e.g. i2cdetect -F 1) should work for root or any user in i2c.
'';
};
config.hardware = lib.mkMerge [
(lib.mkIf cfg.i2c0.enable {
i2c.enable = lib.mkDefault true;
deviceTree = {
overlays = [ (simple-overlay { target = "i2c0if"; status = "okay"; }) ];
};
})
(lib.mkIf cfg.i2c1.enable {
i2c.enable = lib.mkDefault true;
deviceTree = {
overlays = [ (simple-overlay { target = "i2c1"; status = "okay"; }) ];
};
})
];
}