GPIOLED(4) | FreeBSD Kernel Interfaces Manual | GPIOLED(4) |
NAME
gpioled — GPIO led generic device driverDESCRIPTION
The gpioled driver provides a glue to attach a led(4) compatible device to a GPIO pin. Each led on the system has a name which is used to export a device in /dev/led/<name>. The GPIO pin can then be controlled by writing to this device as described on led(4). On a hint based system, like MIPS
, these values are configureable for
gpioled:
- hint.gpioled.%d.at
- The gpiobus you are attaching to. Normally assigned to gpiobus0.
- hint.gpioled.%d.name
- Arbitrary name of device in /dev/led/ to create for led(4).
- hint.gpioled.%d.pins
- Which pin on the GPIO interface to map to this instance. Please note that this mask should only ever have one bit set (any others bits - i.e., pins - will be ignored).
On a FDT(4) based system, like ARM
, the dts part for a
gpioled device usually looks like:
gpio: gpio { gpio-controller; ... led0 { compatible = "gpioled"; gpios = <&gpio 16 2 0>; /* GPIO pin 16. */ name = "ok"; }; led1 { compatible = "gpioled"; gpios = <&gpio 17 2 0>; /* GPIO pin 17. */ name = "user-led1"; }; };
And optionally, you can choose combine all the leds under a single “gpio-leds” compatible node:
simplebus0 { ... leds { compatible = "gpio-leds"; led0 { gpios = <&gpio 16 2 0>; name = "ok" }; led1 { gpios = <&gpio 17 2 0>; name = "user-led1" }; }; };
Both methods are equally supported and it is possible to have the leds defined with any sort of mix between the methods. The only restriction is that a GPIO pin cannot be mapped by two different (gpio)leds.
For more details about the gpios property, please consult /usr/src/sys/boot/fdt/dts/bindings-gpio.txt.
The property name is the arbitrary name of device in /dev/led/ to create for led(4).
HISTORY
The gpioled manual page first appeared in FreeBSD 10.1.AUTHORS
This manual page was written by .May 14, 2014 | FreeBSD |