NAME
gpioiic —
GPIO I2C controller
SYNOPSIS
gpioiic* at gpio? offset 0 mask 0x3 flag
0x0
gpioiic* at gpio?
iic* at gpioiic?
DESCRIPTION
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 19.
SEE ALSO
HISTORY
The gpioiic driver first appeared in
OpenBSD 3.9.
AUTHORS
The gpioiic driver was written by
Alexander Yurchenko
<grange@openbsd.org>.