The gpiolib registers the value attribute in this way:
static const DEVICE_ATTR(value, 0644, gpio_value_show, gpio_value_store);
It creates a device attribute named value
, with permission 644
; on read it calls gpio_value_show
, on write it calls gpio_value_store
What sysfs does, is to redirect read
and write
to the correspondent function of a sysfs attribute.