driver-api/gpio/consumer.rst

6 it describes the new descriptor-based interface. For a description of the
7 deprecated integer-based GPIO interface please refer to legacy.rst.
23 - Simple compile coverage with e.g. COMPILE_TEST - it does not matter that
27 - Truly optional GPIOLIB support - where the driver does not really make use
28   of the GPIOs on certain compile-time configurations for certain systems, but
29   will use it under other compile-time configurations. In this case the
37 All the functions that work with the descriptor-based GPIO interface are
47 With the descriptor-based interface, GPIOs are identified with an opaque,
48 non-forgeable handler that must be obtained through a call to one of the
64 see Documentation/driver-api/gpio/board.rst
80 whether the line is configured active high or active low (see
89 with IS_ERR() (they will never return a NULL pointer). -ENOENT will be returned
96 instead of -ENOENT if no GPIO has been assigned to the requested function::
110 -ENOSYS return codes.  System integrators should however be careful to enable
129 The following function returns NULL instead of -ENOENT if no GPIOs have been
136 Device-managed variants of these functions are also defined::
175 The device-managed variants are, unsurprisingly::
186 -----------------
188 direction-setting flags have been given to gpiod_get*(), this is done by
197 for spinlock-safe GPIOs it is OK to use them before tasking is enabled, as part
214 Spinlock-Safe GPIO Access
215 -------------------------
217 don't need to sleep, and can safely be done from inside hard (non-threaded) IRQ
225 The values are boolean, zero for low, nonzero for high. When reading the value
228 open-drain signaling and output latencies.
238 --------------------------
255 IRQ handler, and those accessors must be used instead of spinlock-safe
260 spinlock-safe calls.
265 The active low and open drain semantics
266 ---------------------------------------
269 the *logical* value. With this they take the active low property into account.
270 This means that they check whether the GPIO is configured to be active low,
275 actively drive their output high (open drain) or low (open source), they just
280 parameter "value" as "asserted" ("1") or "de-asserted" ("0"). The physical line
283 As an example, if the active low property for a dedicated GPIO is set, and the
285 will be driven low.
290   gpiod_set_raw_value(desc, 0);      don't care             low
292   gpiod_set_value(desc, 0);          default (active high)  low
293   gpiod_set_value(desc, 1);          default (active high)  high
294   gpiod_set_value(desc, 0);          active low             high
295   gpiod_set_value(desc, 1);          active low             low
296   gpiod_set_value(desc, 0);          open drain             low
302 but it should be avoided as much as possible, especially by system-agnostic drivers
308 -------------------------
313 The following set of calls ignore the active-low or open drain property of a GPIO and
322 The active low state of a GPIO can also be queried and toggled using the
333 -------------------------------------------------
378 	* array_size	- the number of array elements
379 	* desc_array	- an array of GPIO descriptors
380 	* array_info	- optional information obtained from gpiod_get_array()
381 	* value_bitmap	- a bitmap to store the GPIOs' values (get) or
390 	gpiod_set_array_value(my_gpio_descs->ndescs, my_gpio_descs->desc,
391 			      my_gpio_descs->info, my_gpio_value_bitmap);
417 --------------------
429 Non-error values returned from gpiod_to_irq() can be passed to request_irq() or
431 by the board-specific initialization code. Note that IRQ trigger options are
451 For details refer to Documentation/firmware-guide/acpi/gpio-properties.rst
457 integer-based interface. It is strongly recommended to update these to the new
460 and vice-versa::