1.\" 2.\" SPDX-License-Identifier: BSD-2-Clause 3.\" 4.\" Copyright (c) 2020 Andriy Gapon <avg@FreeBSD.org> 5.\" 6.\" Redistribution and use in source and binary forms, with or without 7.\" modification, are permitted provided that the following conditions 8.\" are met: 9.\" 1. Redistributions of source code must retain the above copyright 10.\" notice, this list of conditions and the following disclaimer. 11.\" 2. Redistributions in binary form must reproduce the above copyright 12.\" notice, this list of conditions and the following disclaimer in the 13.\" documentation and/or other materials provided with the distribution. 14.\" 15.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 16.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 17.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 18.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 19.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 20.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 21.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 22.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 23.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 24.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 25.\" SUCH DAMAGE. 26.\" 27.Dd August 12, 2020 28.Dt CP2112 4 29.Os 30.Sh NAME 31.Nm cp2112 32.Nd driver for a USB GPIO and I2C peripheral device 33.Sh SYNOPSIS 34To compile this driver into the kernel, 35place the following lines in your 36kernel configuration file: 37.Bd -ragged -offset indent 38.Cd "device cp2112" 39.Cd "device usb" 40.Cd "device gpio" 41.Cd "device iicbus" 42.Ed 43.Pp 44Alternatively, to load the driver as a 45module at boot time, place the following line in 46.Xr loader.conf 5 : 47.Bd -literal -offset indent 48cp2112_load="YES" 49.Ed 50.Sh DESCRIPTION 51The 52.Nm 53driver provides support for Silicon Labs CP2112 device. 54The device has 8 general purpose I/O pins and an I2C controller that supports 55a subset of the I2C protocol. 56.Pp 57All pins support both input and output modes. 58An output pin can be configured either for open-drain or push-pull operation. 59Pins 0, 1 and 7 support special functions: I2C transmit indication, 60I2C receive indication and clock output respectively. 61At the moment the 62.Nm 63driver does not provide a way to enable and configure the special functions. 64.Pp 65The I2C controller supports read transactions with up to 512 bytes of data, 66write transactions with up to 61 bytes of data and a write followed by 67the repeated start followed by a read transactions where the write can be 68up to 16 bytes and the read can be up to 512 bytes. 69Zero length transfers are not supported. 70The 71.Nm 72driver creates a 73.Xr gpio 4 74and 75.Xr iicbus 4 76child buses to expose the respective functions. 77.Sh SEE ALSO 78.Xr gpio 4 , 79.Xr iicbus 4 , 80.Xr usb 4 81.Sh HISTORY 82The 83.Nm 84driver and this manual page was written by 85.An Andriy Gapon Aq Mt avg@FreeBSD.org . 86