GPIOLOCK(4) BSD Kernel Interfaces Manual GPIOLOCK(4)NAME
gpiolock -- support for multi-position keylocks attached to GPIO pins
SYNOPSIS
gpiolock* at gpio? offset ? mask ?
gpiolock* at gpio?
DESCRIPTION
The gpiolock driver allows connecting of multi-position keylocks over GPIO pins. The keylock driver registers with an in-kernel keylock sup-
porting system and provides kauth(9) support through an experimental security model. The keylock state can be queried using the hw.keylock
sysctl variables. Only locks with 2-4 positions are currently supported. The pin number is specified in the kernel configuration with the
offset locator. The mask locator denotes the pins used for the lock (minimum 2, maximum 4 pins are used). The offset and mask can also be
specified when gpiolock is attached at runtime using the GPIOATTACH ioctl(2) on the gpio(4) device.
SEE ALSO gpio(4), intro(4)HISTORY
The gpiolock driver first appeared in NetBSD 6.0.
AUTHORS
The gpiolock driver was written by Marc Balmer <marc@msys.ch>.
BSD August 21, 2009 BSD
Check Out this Related Man Page
GPIOIIC(4) BSD Kernel Interfaces Manual GPIOIIC(4)NAME
gpioiic -- GPIO I2C bit-banging device driver
SYNOPSIS
To compile this driver into the kernel, place the following lines in your kernel configuration file:
device gpio
device gpioiic
device iic
device iicbb
device iicbus
DESCRIPTION
The gpioiic driver provides an IIC bit-banging interface using two GPIO pins for the SCL and SDA on the gpiobus. gpioiic implements an open
collector kind of output, as recommended by the standard, when driving the pins on the gpiobus, i.e, they are never switched to the logical
value of '1', or they are '0' or simply open (Hi-Z/tri-state). So the pullup resistors are required so gpioiic can work.
On a device.hints(5) based system, like MIPS, these values are configurable for the gpioiic:
hint.gpioiic.%d.at The gpiobus you are attaching to. Normally just gpiobus0.
hint.gpioiic.%d.pins This is a bitmask of the pins on the gpiobus that are to be used for SCLOCK and SDATA from the GPIO IIC bit-banging
bus. To configure pin 0 and 7, use the bitmask of 0b10000001 and convert it to a hexadecimal value of 0x0081. Please
note that this mask should only ever have two bits set (any other bits - i.e., pins - will be ignored).
hint.gpioiic.%d.scl Indicates which bit in the hint.gpioiic.%d.pins should be used as the SCLOCK source. Optional, defaults to 0.
hint.gpioiic.%d.sda Indicates which bit in the hint.gpioiic.%d.pins should be used as the SDATA source. Optional, defaults to 1.
On a FDT(4) based system, like ARM, the DTS part for a gpioiic device usually looks like:
gpio: gpio {
gpio-controller;
...
gpioiic0 {
compatible = "gpioiic";
/*
* Attach to GPIO pins 21 and 22. Set them
* initially as inputs.
*/
gpios = <&gpio 21 1 0
&gpio 22 1 0>;
scl = <0>; /* GPIO pin 21 - optional */
sda = <1>; /* GPIO pin 22 - optional */
/* This is an example of a gpioiic child. */
gpioiic-child0 {
compatible = "lm75";
i2c-address = <0x4f>;
};
};
};
Where:
compatible Should always be set to "gpioiic".
gpios The gpios property indicates which GPIO pins should be used for SCLOCK and SDATA on the GPIO IIC bit-banging bus. For more
details about the gpios property, please consult /usr/src/sys/boot/fdt/dts/bindings-gpio.txt.
scl The scl option indicates which bit in the gpios should be used as the SCLOCK source. Optional, defaults to 0.
sda The sda option indicates which bit in the gpios should be used as the SDATA source. Optional, defaults to 1.
SEE ALSO fdt(4), gpio(4), gpioled(4), iic(4), iicbb(4), iicbus(4)HISTORY
The gpioiic manual page first appeared in FreeBSD 10.1.
AUTHORS
This manual page was written by Luiz Otavio O Souza.
BSD May 14, 2014 BSD