admin-guide/gpio/sysfs.rst

7   Documentation/ABI/obsolete/sysfs-gpio AND NEW USERSPACE CONSUMERS
16 ------------------------
27 then changing its output state, then updating the code before re-enabling
37 PLEASE READ THE DOCUMENT AT Documentation/driver-api/gpio/drivers-on-gpio.rst
41 --------------
44    -	Control interfaces used to get userspace control over GPIOs;
46    -	GPIOs themselves; and
48    -	GPIO controllers ("gpio_chip" instances).
52 The control interfaces are write-only:
91 		If the pin can be configured as interrupt-generating interrupt
93 		description of "edge"), you can poll(2) on that file and
94 		poll(2) will return whenever the interrupt was triggered. If
95 		you use poll(2), set the events POLLPRI and POLLERR. If you
97 		poll(2) returns, either lseek(2) to the beginning of the sysfs
98 		file and read the new value or close the file and re-open it
104 		that will make poll(2) on the "value" file return.
106 		This file exists only if the pin can be configured as an
113 		poll(2) support configuration via the edge attribute
119 read-only attributes:
130 		how many GPIOs this manages (N to N + ngpio - 1)
141 --------------------------
155 After a kernel driver requests a GPIO, it may only be made available in
161 of experiments easier), or can provide an always-there interface that's