A kernel module that exposes the Framework Laptop (13, 16)'s battery charge limit and LEDs to userspace.

## Install

### Packages

On Arch Linux, this module is packaged in the Arch User Repository as
[`framework-laptop-kmod-dkms-git`](https://aur.archlinux.org/packages/framework-laptop-kmod-dkms-git).
You can install it for all your locally installed kernels with your favorite
AUR helper:

```console
$ yay -S framework-laptop-kmod-dkms-git
```
On Gentoo Linux, this module is packaged in the official Gentoo main repository as
[`framework-laptop-kmod`](https://packages.gentoo.org/packages/app-laptop/framework-laptop-kmod).
You can install it for your current kernel via:

```console
$ emerge --ask framework-laptop-kmod
```

### Building

By default, this project will try to build a module for your running kernel.

```console
$ make
```

If you need to target a different kernel, set `KDIR`:

```console
$ make KDIR=/usr/src/linux-6.5
```

You can install the module systemwide with `make modules_install`.

## Usage

If the module is installed systemwide, you can load it with 
`modprobe framework_laptop`. If you built it manually, you can also use
`insmod ./framework_laptop.ko`.

This module requires `cros_ec` and `cros_ec_lpcs` to be loaded and functional.

> [!NOTE]
> For the Framework Laptop 13 AMD Ryzen 7040 series and the Framework Laptop 16,
> you will either need to apply [this patch series](https://lore.kernel.org/chrome-platform/20231005160701.19987-1-dustin@howett.net/) to your kernel sources, or run kernel version 6.10 or higher.

### Battery Charge Limit

- Exposed via `charge_control_end_threshold`, available on `BAT1`
   - `/sys/class/power_supply/BAT1/charge_control_end_threshold`

### LEDs

- `/sys/class/leds/framework_laptop::kbd_backlight`

### Fan Control

This driver supports up to 4 fans, and creates a HWMON interface with the name `framework_laptop`.

- `fan[1-4]_input` - Read fan speed in RPM (read-only)
- `fan[1-4]_target` - Set target fan speed in RPM
  - read-write on the first fan, write-only on the others
- `fan[1-4]_fault` - Fan removed indicator (read-only)
- `fan[1-4]_alarm` - Fan stall indicator (read-only)
- `pwm[1-4]` - Fan speed control in percent 0-100 (write-only)
- `pwm[1-4]_enable` - Enable automatic fan control (write-only)
  - Currently you can write anything to enable, but writing `2` is recommended in case the driver is updated to support disabling automatic fan control.
  - Writing to the other interfaces will disable automatic fan control.
- `pwm[1-4]_min` - returns 0 (read-only)
- `pwm[1-4]_max` - returns 100 (read-only)

### Privacy Switches

This driver exposes the privacy switches as a custom SysFS interface under `/sys/devices/platform/framework_laptop/framework_privacy`.
It follows the [existing format of the `dell-privacy` driver](https://www.kernel.org/doc/Documentation/ABI/testing/sysfs-platform-dell-privacy-wmi).