---
name: "glxiic"
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/glxiic"
---

# glxiic(4)

Geode LX CS5536 I2C controller driver

## NAME

**glxiic** – Geode LX CS5536 I2C controller driver

## SYNOPSIS

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

**device pci** **device isa** **device glxiic** **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):

```
glxiic_load="YES"
```

## DESCRIPTION

The **glxiic** driver supports the System Management Bus controller of the Geode LX series CS5536 Companion Device. The Geode LX is a member of the AMD Geode family of integrated x86 system chips.

Although AMD refers to this device as a System Management Bus (SMBus) controller, it is really an I2C controller (it lacks SMBus ALERT# and Alert Response support).

The **glxiic** driver supports both I2C master and slave mode.

## SYSCTL VARIABLE

The **glxiic** driver supports the following variable as both [sysctl(8)](/sysctl/8.md) and [loader(8)](/loader/8.md) tunable:

- *dev.glxiic.0.timeout*

  This variable controls the I2C bus timeout in milliseconds. The default timeout is 35 milliseconds. A value of zero disables the timeout.

## CAVEAT

The **glxiic** driver uses the interrupt line number configured by the board firmware by default. If no interrupt line number has been configured by the board firmware (or to override the interrupt line number configured by board firmware), place the following line in [device.hints(5)](/device.hints/5.md):

hint.glxiic.0.irq="10"

The interrupt line number must be between 1 and 15.

## SEE ALSO

[iicbus(4)](/iicbus/4.md), [device.hints(5)](/device.hints/5.md), [loader.conf(5)](/loader.conf/5.md), [loader(8)](/loader/8.md), [sysctl(8)](/sysctl/8.md)

## HISTORY

The **glxiic** device driver and manual page first appeared in FreeBSD 9.0.

## AUTHORS

The **glxiic** device driver and manual page were written by Henrik Brix Andersen ⟨*brix@FreeBSD.org*⟩.