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$FreeBSD: stable/10/share/man/man4/gpioled.4 266105 2014-05-15 01:27:53Z loos $
.Dd February 13, 2014 .Dt GPIOLED 4 .Os .Sh NAME .Nm gpioled .Nd GPIO led generic device driver .Sh SYNOPSIS .Cd "device gpio" .Cd "device gpioled"
p This driver attaches a .Xr led 4 device to a GPIO pin. .Sh DESCRIPTION The .Em gpioled driver provides a glue to attach a .Xr led 4 compatible device to a GPIO pin. Each led on the system has a
a name which is used to export a device in
a /dev/led/<name> . The GPIO pin can then be controlled by writing to this device as described on .Xr led 4 .
p On a hint based system, like .Li MIPS , these values are configureable for .Nm : l -tag -width ".Va hint.gpioiic.%d.atXXX" t Va hint.gpioled.%d.at The gpiobus you are attaching to. Normally assigned to gpiobus0. t Va hint.gpioled.%d.name Arbitrary name of device in
a /dev/led/ to create for .Xr led 4 . t Va 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). .El
p On a .Xr FDT 4 based system, like .Li ARM , the dts part for a .Nm gpioled device usually looks like: d -literal 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"; }; }; .Ed
p And optionally, you can choose combine all the leds under a single .Dq gpio-leds compatible node: d -literal simplebus0 { ... leds { compatible = "gpio-leds"; led0 { gpios = <&gpio 16 2 0>; name = "ok" }; led1 { gpios = <&gpio 17 2 0>; name = "user-led1" }; }; }; .Ed
p 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.
p For more details about the .Va gpios property, please consult
a /usr/src/sys/boot/fdt/dts/bindings-gpio.txt .
p The property .Va name is the arbitrary name of device in
a /dev/led/ to create for .Xr led 4 . .Sh SEE ALSO .Xr fdt 4 , .Xr gpio 4 , .Xr led 4 , .Xr gpioiic 4 .Sh HISTORY The .Nm manual page first appeared in .Fx 11.0 . .Sh AUTHORS This manual page was written by .An Luiz Otavio O Souza .