Lines Matching +full:output +full:- +full:low
21 - Simple compile coverage with e.g. COMPILE_TEST - it does not matter that
25 - Truly optional GPIOLIB support - where the driver does not really make use
26 of the GPIOs on certain compile-time configurations for certain systems, but
27 will use it under other compile-time configurations. In this case the
35 All the functions that work with the descriptor-based GPIO interface are
45 With the descriptor-based interface, GPIOs are identified with an opaque,
46 non-forgeable handler that must be obtained through a call to one of the
62 see Documentation/driver-api/gpio/board.rst
70 * GPIOD_OUT_LOW to initialize the GPIO as output with a value of 0.
71 * GPIOD_OUT_HIGH to initialize the GPIO as output with a value of 1.
78 whether the line is configured active high or active low (see
87 with IS_ERR() (they will never return a NULL pointer). -ENOENT will be returned
94 instead of -ENOENT if no GPIO has been assigned to the requested function::
108 -ENOSYS return codes. System integrators should however be careful to enable
127 The following function returns NULL instead of -ENOENT if no GPIOs have been
134 Device-managed variants of these functions are also defined::
173 The device-managed variants are, unsurprisingly::
184 -----------------
186 direction-setting flags have been given to gpiod_get*(), this is done by
195 for spinlock-safe GPIOs it is OK to use them before tasking is enabled, as part
198 For output GPIOs, the value provided becomes the initial output value. This
205 This function returns 0 for output, 1 for input, or an error code in case of error.
212 Spinlock-Safe GPIO Access
213 -------------------------
215 don't need to sleep, and can safely be done from inside hard (non-threaded) IRQ
224 value of an output pin, the value returned should be what's seen on the pin.
225 That won't always match the specified output value, because of issues including
226 open-drain signaling and output latencies.
230 can read the value of output pins; those that can't should always return zero.
236 --------------------------
253 IRQ handler, and those accessors must be used instead of spinlock-safe
258 spinlock-safe calls.
263 The active low and open drain semantics
264 ---------------------------------------
267 the *logical* value. With this they take the active low property into account.
268 This means that they check whether the GPIO is configured to be active low,
272 The same is applicable for open drain or open source output lines: those do not
273 actively drive their output high (open drain) or low (open source), they just
274 switch their output to a high impedance value. The consumer should not need to
281 As an example, if the active low property for a dedicated GPIO is set, and the
283 will be driven low.
288 gpiod_set_raw_value(desc, 0); don't care low
290 gpiod_set_value(desc, 0); default (active high) low
292 gpiod_set_value(desc, 0); active low high
293 gpiod_set_value(desc, 1); active low low
294 gpiod_set_value(desc, 0); open drain low
300 but it should be avoided as much as possible, especially by system-agnostic drivers
306 -------------------------
311 The following set of calls ignore the active-low or open drain property of a GPIO and
320 The active low state of a GPIO can also be queried and toggled using the
331 -------------------------------------------------
376 * array_size - the number of array elements
377 * desc_array - an array of GPIO descriptors
378 * array_info - optional information obtained from gpiod_get_array()
379 * value_bitmap - a bitmap to store the GPIOs' values (get) or
388 gpiod_set_array_value(my_gpio_descs->ndescs, my_gpio_descs->desc,
389 my_gpio_descs->info, my_gpio_value_bitmap);
415 --------------------
427 Non-error values returned from gpiod_to_irq() can be passed to request_irq() or
429 by the board-specific initialization code. Note that IRQ trigger options are
449 For details refer to Documentation/firmware-guide/acpi/gpio-properties.rst
455 integer-based interface. It is strongly recommended to update these to the new
458 and vice-versa::