GPIOIIC(4) Kernel Interfaces Manual GPIOIIC(4)
gpioiic -- GPIO I2C controller
gpioiic* at gpio? offset 0 mask 0x3 flag 0x0
gpioiic* at gpio?
iic* at gpioiic?
The gpioiic driver allows bit-banging an I2C bus as a master using two
GPIO pins. By default the first pin is used as a serial data (SDA)
signal and the second as a serial clock (SCL). If the flag locator is
set to 0x01, the order of the SDA and SCL signals is reversed. Both GPIO
pins must be able to drive an output and the SDA pin must be also able to
read an input.
The pins can be specified in the kernel configuration with the offset and
the mask locators. The offset and mask can also be specified when
gpioiic is attached at runtime using the GPIOATTACH ioctl(2) on the
gpio(4) device. Each bit in the mask locator defines one pin; the pin
number is calculated as an addition of the bit position and the offset
locator. For example, offset 17 and mask 0x5 defines pin numbers 17 and
gpio(4), iic(4), intro(4)
The gpioiic driver first appeared in OpenBSD 3.9 and NetBSD 5.0.
The gpioiic driver was written by Alexander Yurchenko
<grangeATopenbsd.org> and was ported to NetBSD by Marc Balmer
A gpioiic device can not be detached from the gpio(4) bus at runtime due
to the fact that iic(4) busses can not detach once attached.
NetBSD 6.1.5 October 2, 2011 NetBSD 6.1.5