[GUIDE] Turn LID GPIO 27 into a standard input device sending lid switch events

ONE UP
1

Hi folks!

I was bothered by the fact that I had to use a proprietary daemon to use a standard device like a lid switch on my One Up, so I have created this overlay for a gpio-based input device.

Now I can simply use standard tools to react to the state of the shell’s lid.

Here’s my overlay’s dts:

[root@argon-oneup overlays]$ cat lid.dts 
/dts-v1/;
/plugin/;

/ {
    compatible = "brcm,bcm2712";

    fragment@0 {
        target = <&rp1_gpio>;
        __overlay__ {
            lid_switch_pins: lid_switch_pins {
                pins = "gpio27";
                function = "gpio";
                bias-pull-up;
                input-enable;
                input-schmitt-enable;
            };
        };
    };

    fragment@1 {
        target-path = "/";
        __overlay__ {
            lid_switch {
                pinctrl-names = "default";
                pinctrl-0 = <&lid_switch_pins>;
                compatible = "gpio-keys";
                status = "okay";

                lid {
                    label = "lid_switch";
                    phandle = <0x61>;
                    linux,input-type = <0x05>;   // EV_SW
                    linux,code = <0x00>;         // SW_LID
                    debounce-interval = <0x32>;
                    gpios = <&rp1_gpio 27 1>;    // 1 = GPIO_ACTIVE_LOW (invert)
                };
            };
        };
    };
};
[root@argon-oneup overlays]$

Just like always simply compile with dtc -@ -I dts -O dtb -o lid.dtbo lid.dts and apply the overlay in your config.txt.

This will result in your lid switch showing up as a separate input device like this:

[root@argon-oneup ~]# libinput list-devices

Device:                  lid_switch
Kernel:                  /dev/input/event0
Id:                      host:0001:0001
Group:                   4
Seat:                    seat0, default
Capabilities:            switch
Tap-to-click:            n/a
Tap-and-drag:            n/a
Tap button map:          n/a
Tap drag lock:           n/a
Left-handed:             n/a
Nat.scrolling:           n/a
Middle emulation:        n/a
Calibration:             n/a
Scroll methods:          none
Scroll button:           n/a
Scroll button lock:      n/a
Click methods:           none
Clickfinger button map:  n/a
Disable-w-typing:        n/a
Disable-w-trackpointing: n/a
Accel profiles:          n/a
Rotation:                0.0
Area rectangle:          n/a

[root@argon-oneup ~]#

and it’ll send lid switch events just like any other standard lid out there does:

[root@argon-oneup ~]# libinput debug-events --device /dev/input/event0

-event0   DEVICE_ADDED                 lid_switch                        seat0 default group1  cap:S
 event0   SWITCH_TOGGLE                +0.000s	switch lid state 1
 event0   SWITCH_TOGGLE                +2.500s	switch lid state 0

[root@argon-oneup ~]#

Now you can set up systemd-logind or your favourite desktop environment to handle the lid switch as you’re used to.

Hope this’ll help anyone.

3 Likes
2

Great, thanks for the guide!

Before I try it out, do I need to disable any specific services? I currently have the Argon script installed, but I’ve kept argononeupd.service deactivated to maintain compatibility with Jeff’s battery driver.

3

No, there’s nothing that you need to disable. The argononeupd.service (that you aren’t using anyway) won’t be able to to grab the gpio pin since the driver has a lock on it already, but that’s all.

I am also waiting for Jeff’s battery driver to mature a bit. Looks promising.

4

This is awesome, thanks!