[PATCH] Add Linux gpio sysfs applets

[Ralf Friedl]

Sascha Hauer wrote:
> This adds applets for manipulating gpios under Linux via sysfs. It uses
> the /sys/class/gpio API to set direction and value of gpios and to read
> back the actual value. The applets work like the corresponding C functions
> in the kernel:
>
> gpio_set_value <gpio> <value>
> gpio_get_value <gpio>
> gpio_direction_output <gpio> <value>
> gpio_direction_input <gpio>
>
> <gpio> is the Linux gpio number and <value> is 0 for low and 1 for high.
> gpio_get_value will report the value to stdout.
>
> If not already exported the applets export the gpio via
> /sys/class/gpio/export. After usage the gpio is unexported again,
> but only if it wasn't exported before calling the applet.
What is the advantage of these applets compared to a direct echo to 
/sys/class/gpio/... ?