---
name: "isl"
section: "4"
platform: "freebsd"
package: "base"
version: "16.0-CURRENT-20261027-61c70dc16a79"
release: "FreeBSD 16.0-CURRENT (2026-10-27)"
platforms: ["freebsd"]
url: "https://new.carta.tech/isl"
---

# isl(4)

Intersil(TM) I2C ISL29018 sensor driver

## NAME

**isl** – Intersil(TM) I2C ISL29018 sensor driver

## SYNOPSIS

To compile this driver into the kernel, place the following lines into the kernel configuration file:

**device isl** **device ig4** **device iicbus**

Alternatively, to load the driver as a module at boot time, place the following line in [loader.conf(5)](/loader.conf/5.md):

```
isl_load="YES"
ig4_load="YES"
```

On many Chromebook models this driver can be automatically configured with the help of the [chromebook\_platform(4)](/chromebook_platform/4.md) driver. Alternatively, the

**isl** driver can be manually configured in */boot/device.hints*: **hint.isl.0.at="iicbus0"** **hint.isl.0.addr="0x88"** **hint.isl.1.at="iicbus1"** **hint.isl.1.addr="0x88"**

## DESCRIPTION

The **isl** driver provides access to sensor data provided by the Intersil(TM) I2C ISL29018 Digital Ambient Light Sensor and Proximity Sensor with Interrupt Function. Functionality is basic and provided through the [sysctl(8)](/sysctl/8.md) interface.

On a system using [device.hints(5)](/device.hints/5.md), these values are configurable for **isl**:

- *hint.isl.%d.at*

  target [iicbus(4)](/iicbus/4.md).

- *hint.isl.%d.addr*

  **isl** i2c address on the [iicbus(4)](/iicbus/4.md).

## SYSCTL VARIABLES

The following [sysctl(8)](/sysctl/8.md) variables are available:

- *dev.isl.X.als*

  Current ALS (Ambient Light Sensor) readout.

- *dev.isl.X.ir*

  Current IR (InfraRed) sensor readout.

- *dev.isl.X.prox*

  Current proximity sensor readout.

- *dev.isl.X.resolution*

  Current sensor resolution.

- *dev.isl.X.range*

  Current sensor range.

## EXAMPLES

### Ambient light sensor read out

```
$ sysctl dev.isl.0.als
dev.isl.0.als: 64
```

### Automatically adjust brightness

This requires the port *graphics/intel-backlight* and only works with laptops using a supported Intel(R) GPU.

```
$ pkg install intel-backlight
$ sh /usr/local/share/examples/intel-backlight/isl_backlight.sh
```

## SEE ALSO

[chromebook\_platform(4)](/chromebook_platform/4.md), [ig4(4)](/ig4/4.md), [iicbus(4)](/iicbus/4.md)

## AUTHORS

The **isl** driver was written by Michael Gmelin ⟨*freebsd@grem.de*⟩.

This manual page was written by Michael Gmelin ⟨*freebsd@grem.de*⟩.

## BUGS

The **isl** driver detects the device based from the I2C address. This might have unforeseen consequences if the initialization sequence is sent to an unknown device at that address.