gpio-cdev-go is pure Go library to access Linux 4.8+ GPIO chardev interface.
Tested on:
- ARMv6,7 RaspberryPi 1, OrangePi Lite
- ARM64 RaspberryPi 3 B+
If you know how to make this work useful for more people, please take a minute to communicate:
Ultimate success would be to merge this functionality into periph.io lib.
Low level, bare ioctl API is provided by set of Raw* functions.
High-level wrapper (see api.go) is recommended way to use library.
// Open GPIO chip device.
// Default consumer tag will be used if one is not provided to line management functions.
chip, err := gpio.Open("/dev/gpiochip0", "default-consumer")
defer chip.Close()
// Set lines via either `SetBulk(values ...byte)`
// or create setter closure with `SetFunc(line) -> func(bool)`
// Either way you should call `Flush()` to commit changes to hardware.
pins, err := chip.OpenLines(
gpio.GPIOHANDLE_REQUEST_OUTPUT, "hd44780",
nRS, nRW, nE, nD4, nD5, nD6, nD7,
)
defer pins.Close()
pins.SetBulk(1, 0, 0, 1, 1, 1, 1)
err := pins.Flush()
set_pin_d4 := pins.SetFunc(nD4)
set_pin_d4(true)
err := pins.Flush()
// Reading current lines state
pins, err := chip.OpenLines(gpio.GPIOHANDLE_REQUEST_INPUT, "consumer", uint32(line))
defer pins.Close()
data, err := pins.Read()
lineActive := data.Values[0] == 1
// Waiting for edge. REQUEST_INPUT flag is implied.
lineEvent, err := chip.GetLineEvent(uint32(notifyLine), /*RequestFlag*/ 0,
gpio.GPIOEVENT_REQUEST_RISING_EDGE, "consumer")
defer lineEvent.Close()
currentValue, err := lineEvent.Read()
eventData, err := lineEvent.Wait(timeout) // 0 to block forever
ok := eventData.ID == GPIOEVENT_EVENT_RISING_EDGE
- may leak
req.fddescriptors, TODO test
- get 2 free GPIO pins
- jumper them
- set environment variables and run tests
export GPIO_TEST_DEV="/dev/gpiochip0"
export GPIO_TEST_PIN="19"
export GPIO_TEST_PIN_LOOP="16"
go test ./...
