CP2112(4)

📦 version 12.2, in debian bookworm, debian trixie, ubuntu jammy, ubuntu noble, ubuntu questing, ubuntu resolute, ubuntu stonking

✨ CP2112(4) ✨

okay bestie, welcome to the Kernel Interfaces Manual 💖 this one's about the cp2112 driver — a driver for a USB GPIO and I2C peripheral device. yes, both. it's a multitasker. we love her for that. 🫶

🌸 NAME 🌸

cp2112 — driver for a USB GPIO and I2C peripheral device

literally what it says on the tin, no notes 💅

🎀 SYNOPSIS 🎀

so if you wanna bake this driver right into your kernel, you gotta put these lines in your kernel configuration file. all four. no skipping, bestie, this is a full fit not a two-piece 🦋

device cp2112
device usb
device gpio
device iicbus

orrr, if you'd rather load it as a module at boot time (iconic, low-commitment, we respect it), drop this single line into loader.conf(5):

cp2112_load="YES"

💅 DESCRIPTION 💅

The cp2112 driver provides support for Silicon Labs CP2112 device. 💖

This little device has 8 general purpose I/O pins and an I2C controller that supports a subset of the I2C protocol. yeah, it does a lot. main character energy fr fr 👑

okay so about the pins — all pins support both input and output modes. every single one. no pin left behind. 🌈

An output pin can be configured either for open-drain or push-pull operation. pick your fighter ✨

Now, pins 0, 1 and 7 support special functions — they're the overachievers of the group:

  • pin 0 — I2C transmit indication
  • pin 1 — I2C receive indication
  • pin 7 — clock output
😭 but here's the sad part: at the moment the cp2112 driver does not provide a way to enable and configure the special functions. so they're just sitting there, gifted and unconfigured. tragic. we're manifesting it for a future release tho 🙈

Now the I2C controller tea, because this is the important part — it supports:

  • read transactions with up to 512 bytes of data
  • write transactions with up to 61 bytes of data
  • a write followed by the repeated start followed by a read transaction, where the write can be up to 16 bytes and the read can be up to 512 bytes

and, bestie, listen: zero length transfers are not supported. not a thing. don't try it. it's giving nothing and it will not work 💀

The cp2112 driver creates a gpio(4) and iicbus(4) child buses to expose the respective functions — so both personalities get to shine ✨

🔥 SEE ALSO 🔥

go read those too, iykyk 📚

👑 HISTORY 👑

The cp2112 driver and this manual page was written by Andriy Gapon <avg@FreeBSD.org>. thank you for your service, legend 🫡💖

and that's the whole page, bestie! this one came to you courtesy of Debian, dated August 12, 2020, and it's filed under CP2112(4). go forth and blink some pins 🌸💅✨

📦 where this page comes from