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CP2112(4) FreeBSD Kernel Interfaces Manual CP2112(4)

driver for a USB GPIO and I2C peripheral device

To compile this driver into the kernel, place the following lines in your kernel configuration file:
device cp2112
device usb
device gpio
device iicbus

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


The cp2112 driver provides support for Silicon Labs CP2112 device. The device has 8 general purpose I/O pins and an I2C controller that supports a subset of the I2C protocol.

All pins support both input and output modes. An output pin can be configured either for open-drain or push-pull operation. Pins 0, 1 and 7 support special functions: I2C transmit indication, I2C receive indication and clock output respectively. At the moment the cp2112 driver does not provide a way to enable and configure the special functions.

The I2C controller supports read transactions with up to 512 bytes of data, write transactions with up to 61 bytes of data and a write followed by the repeated start followed by a read transactions where the write can be up to 16 bytes and the read can be up to 512 bytes. Zero length transfers are not supported. The cp2112 driver creates a gpio(4) and iicbus(4) child buses to expose the respective functions.

gpio(4), iicbus(4), usb(4)

The cp2112 driver and this manual page was written by Andriy Gapon <>.
August 12, 2020 FreeBSD 13.1-RELEASE

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