Lines Matching +full:high +full:- +full:performance
6 it describes the new descriptor-based interface. For a description of the
7 deprecated integer-based GPIO interface please refer to gpio-legacy.txt.
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
33 All the functions that work with the descriptor-based GPIO interface are
43 With the descriptor-based interface, GPIOs are identified with an opaque,
44 non-forgeable handler that must be obtained through a call to one of the
60 see Documentation/driver-api/gpio/board.rst
81 with IS_ERR() (they will never return a NULL pointer). -ENOENT will be returned
88 instead of -ENOENT if no GPIO has been assigned to the requested function::
102 -ENOSYS return codes. System integrators should however be careful to enable
121 The following function returns NULL instead of -ENOENT if no GPIOs have been
128 Device-managed variants of these functions are also defined::
167 The device-managed variants are, unsurprisingly::
178 -----------------
180 direction-setting flags have been given to gpiod_get*(), this is done by
189 for spinlock-safe GPIOs it is OK to use them before tasking is enabled, as part
206 Spinlock-Safe GPIO Access
207 -------------------------
209 don't need to sleep, and can safely be done from inside hard (non-threaded) IRQ
217 The values are boolean, zero for low, nonzero for high. When reading the value
220 open-drain signaling and output latencies.
230 --------------------------
247 IRQ handler, and those accessors must be used instead of spinlock-safe
252 spinlock-safe calls.
256 ---------------------------------------
265 actively drive their output high (open drain) or low (open source), they just
266 switch their output to a high impedance value. The consumer should not need to
270 parameter "value" as "asserted" ("1") or "de-asserted" ("0"). The physical line
281 gpiod_set_raw_value(desc, 1); don't care high
282 gpiod_set_value(desc, 0); default (active high) low
283 gpiod_set_value(desc, 1); default (active high) high
284 gpiod_set_value(desc, 0); active low high
287 gpiod_set_value(desc, 1); open drain high impedance
288 gpiod_set_value(desc, 0); open source high impedance
289 gpiod_set_value(desc, 1); open source high
292 but it should be avoided as much as possible, especially by system-agnostic drivers
298 -------------------------
303 The following set of calls ignore the active-low or open drain property of a GPIO and
321 -------------------------------------------------
360 corresponding chip driver. In that case a significantly improved performance
365 * array_size - the number of array elements
366 * desc_array - an array of GPIO descriptors
367 * array_info - optional information obtained from gpiod_get_array()
368 * value_bitmap - a bitmap to store the GPIOs' values (get) or
377 gpiod_set_array_value(my_gpio_descs->ndescs, my_gpio_descs->desc,
378 my_gpio_descs->info, my_gpio_value_bitmap);
386 Note that for optimal performance GPIOs belonging to the same chip should be
389 Still better performance may be achieved if array indexes of the descriptors
395 banks as data I/O ports without much loss of performance.
404 --------------------
416 Non-error values returned from gpiod_to_irq() can be passed to request_irq() or
418 by the board-specific initialization code. Note that IRQ trigger options are
438 For details refer to Documentation/firmware-guide/acpi/gpio-properties.rst
443 Many kernel subsystems still handle GPIOs using the legacy integer-based
445 descriptor-based API, the following two functions allow you to convert a GPIO
446 descriptor into the GPIO integer namespace and vice-versa::