> Date: Mon, 17 Oct 2022 18:45:30 +0200 > From: Andreas Bergmeier <abergmeier@xxxxxxx> > To: linux-usb@xxxxxxxxxxxxxxx > Subject: Litra Glow on Linux > > On my Ubuntu machine i am running 5.15.0. Now when I plugin in my > Logitech Litra Glow, it gets detected and the following shows up in my > dmesg: > > ``` > input: Logi Litra Glow Consumer Control as > /devices/pci0000:00/0000:00:14.0/usb3/3-4/3-4.2/3-4.2:1.0/0003:046D:C900.000B/input/input75 > hid-generic 0003:046D:C900.000B: input,hiddev0,hidraw2: USB HID v1.11 > Device [Logi Litra Glow] on usb-0000:00:14.0-4.2/input0 > ``` > > Via (hardware) buttons you can switch the device on, regulate the > color temperature as well as the brightness. So I looked into the sources of `hid-input` and `hig-lg` and I hope that I have a halfway decent understanding why the linux modules/dev nodes handle the way they do. What I do not yet understand is how to map the device to input "primitives". To recap there are 5 hardware buttons and 3 states: - State: "Color temperature in range [u, x]" Button: up - State: "Color temperature in range [u, x]" Button: down - State/Button On/Off - State "Brightness in range [y, z]" Button: up - State "Brightness in range [y, z]" Button: down What would be a best practice to expose these correctly via HID (as e.g. ABS_WHEEL?)? Or at least - what are the canonical options? Since the exposed Record interface seems "wrong" I assume I need to write code to fix the device handling. Now, is this better suited in `hid-input` or `hid-lg`? The former currently tries to handle the device (wrongly) and the latter yet ignores the device but seems to be the one stop to fix Logitech devices. > I know of no way to fully control the device from my computer and > would like to change that. By now I am confident that I will soon have the full device control figured out.
