NAME
gpioled — GPIO LED generic device driver
SYNOPSIS
To compile this driver into the kernel, place the following lines in your kernel configuration file:
device gpio
device gpioled
DESCRIPTION
The gpioled driver provides glue to attach a led(4) compatible device to a GPIO pin. Each LED in the system has a name which is used to export a device as /dev/led/<name>. The GPIO pin can then be controlled by writing to this device as described in led(4).
On a device.hints(5) based system, like MIPS, these values are configurable 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 other bits - i.e., pins - will be ignored).
hint.gpioled.%d.invert
If set to 1, the pin will be set to 0 to light the LED, and 1 to clear it.
On a FDT(4) based system, like ARM, the DTS part for a gpioled device usually looks like:
gpio: gpio {
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gpio-controller; |
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... |
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led0 { |
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compatible = "gpioled"; |
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gpios = <&gpio 16 2 0>; |
/* GPIO pin 16. */ |
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name = "ok"; |
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}; |
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led1 { |
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compatible = "gpioled"; |
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gpios = <&gpio 17 2 0>; |
/* GPIO pin 17. */ |
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name = "user-led1"; |
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}; |
};
Optionally, you can choose to combine all the LEDs under a single ’’gpio-leds’’ compatible node:
simplebus0 {
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... |
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leds { |
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compatible = "gpio-leds"; |
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led0 { |
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gpios = <&gpio 16 2 0>; |
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name = "ok" |
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}; |
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led1 { |
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gpios = <&gpio 17 2 0>; |
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name = "user-led1" |
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}; |
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}; |
};
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/dts/bindings-gpio.txt.
The property name is the arbitrary name of the device in /dev/led/ to create for led(4).
SEE ALSO
fdt(4), gpio(4), gpioiic(4), led(4)
HISTORY
The gpioled manual page first appeared in FreeBSD 10.1.
AUTHORS
This manual page was written by Luiz Otavio O Souza.
BSD July 30, 2016 BSD