1 /* SPDX-License-Identifier: GPL-2.0+ */
3 * Copyright (c) 2011 The Chromium OS Authors.
4 * Copyright (c) 2011, NVIDIA Corp. All rights reserved.
7 #ifndef _ASM_GENERIC_GPIO_H_
8 #define _ASM_GENERIC_GPIO_H_
10 #include <dm/ofnode.h>
11 #include <linux/bitops.h>
14 struct ofnode_phandle_args;
17 * Generic GPIO API for U-Boot
20 * NB: This is deprecated. Please use the driver model functions instead:
22 * - gpio_request_by_name()
23 * - dm_gpio_get_value() etc.
25 * For now we need a dm_ prefix on some functions to avoid name collision.
28 * GPIOs are numbered from 0 to GPIO_COUNT-1 which value is defined
29 * by the SOC/architecture.
31 * Each GPIO can be an input or output. If an input then its value can
32 * be read as 0 or 1. If an output then its value can be set to 0 or 1.
33 * If you try to write an input then the value is undefined. If you try
34 * to read an output, barring something very unusual, you will get
35 * back the value of the output that you previously set.
37 * In some cases the operation may fail, for example if the GPIO number
38 * is out of range, or the GPIO is not available because its pin is
39 * being used by another function. In that case, functions may return
40 * an error value of -1.
44 * @deprecated Please use driver model instead
45 * Request a GPIO. This should be called before any of the other functions
46 * are used on this GPIO.
48 * Note: With driver model, the label is allocated so there is no need for
49 * the caller to preserve it.
51 * @param gpio GPIO number
52 * @param label User label for this GPIO
53 * @return 0 if ok, -1 on error
55 int gpio_request(unsigned gpio, const char *label);
58 * @deprecated Please use driver model instead
59 * Stop using the GPIO. This function should not alter pin configuration.
61 * @param gpio GPIO number
62 * @return 0 if ok, -1 on error
64 int gpio_free(unsigned gpio);
67 * @deprecated Please use driver model instead
68 * Make a GPIO an input.
70 * @param gpio GPIO number
71 * @return 0 if ok, -1 on error
73 int gpio_direction_input(unsigned gpio);
76 * @deprecated Please use driver model instead
77 * Make a GPIO an output, and set its value.
79 * @param gpio GPIO number
80 * @param value GPIO value (0 for low or 1 for high)
81 * @return 0 if ok, -1 on error
83 int gpio_direction_output(unsigned gpio, int value);
86 * @deprecated Please use driver model instead
87 * Get a GPIO's value. This will work whether the GPIO is an input
90 * @param gpio GPIO number
91 * @return 0 if low, 1 if high, -1 on error
93 int gpio_get_value(unsigned gpio);
96 * @deprecated Please use driver model instead
97 * Set an output GPIO's value. The GPIO must already be an output or
98 * this function may have no effect.
100 * @param gpio GPIO number
101 * @param value GPIO value (0 for low or 1 for high)
102 * @return 0 if ok, -1 on error
104 int gpio_set_value(unsigned gpio, int value);
106 /* State of a GPIO, as reported by get_function() */
110 GPIOF_UNUSED, /* Not claimed */
111 GPIOF_UNKNOWN, /* Not known */
112 GPIOF_FUNC, /* Not used as a GPIO */
120 struct udevice *dev; /* Device, NULL for invalid GPIO */
122 #define GPIOD_IS_OUT BIT(1) /* GPIO is an output */
123 #define GPIOD_IS_IN BIT(2) /* GPIO is an input */
124 #define GPIOD_ACTIVE_LOW BIT(3) /* GPIO is active when value is low */
125 #define GPIOD_IS_OUT_ACTIVE BIT(4) /* set output active */
126 #define GPIOD_OPEN_DRAIN BIT(5) /* GPIO is open drain type */
127 #define GPIOD_OPEN_SOURCE BIT(6) /* GPIO is open source type */
128 #define GPIOD_PULL_UP BIT(7) /* GPIO has pull-up enabled */
129 #define GPIOD_PULL_DOWN BIT(8) /* GPIO has pull-down enabled */
131 uint offset; /* GPIO offset within the device */
133 * We could consider adding the GPIO label in here. Possibly we could
134 * use this structure for internal GPIO information.
138 /* helper to compute the value of the gpio output */
139 #define GPIOD_FLAGS_OUTPUT_MASK (GPIOD_ACTIVE_LOW | GPIOD_IS_OUT_ACTIVE)
140 #define GPIOD_FLAGS_OUTPUT(flags) \
141 (((((flags) & GPIOD_FLAGS_OUTPUT_MASK) == GPIOD_IS_OUT_ACTIVE) || \
142 (((flags) & GPIOD_FLAGS_OUTPUT_MASK) == GPIOD_ACTIVE_LOW)))
145 * dm_gpio_is_valid() - Check if a GPIO is valid
147 * @desc: GPIO description containing device, offset and flags,
148 * previously returned by gpio_request_by_name()
149 * @return true if valid, false if not
151 static inline bool dm_gpio_is_valid(const struct gpio_desc *desc)
153 return desc->dev != NULL;
157 * gpio_get_status() - get the current GPIO status as a string
159 * Obtain the current GPIO status as a string which can be presented to the
160 * user. A typical string is:
162 * "b4: in: 1 [x] sdmmc_cd"
164 * which means this is GPIO bank b, offset 4, currently set to input, current
165 * value 1, [x] means that it is requested and the owner is 'sdmmc_cd'
167 * TODO(sjg@chromium.org): This should use struct gpio_desc
169 * @dev: Device to check
170 * @offset: Offset of device GPIO to check
171 * @buf: Place to put string
172 * @buffsize: Size of string including \0
174 int gpio_get_status(struct udevice *dev, int offset, char *buf, int buffsize);
177 * gpio_get_function() - get the current function for a GPIO pin
179 * Note this returns GPIOF_UNUSED if the GPIO is not requested.
181 * TODO(sjg@chromium.org): This should use struct gpio_desc
183 * @dev: Device to check
184 * @offset: Offset of device GPIO to check
185 * @namep: If non-NULL, this is set to the name given when the GPIO
186 * was requested, or -1 if it has not been requested
187 * @return -ENODATA if the driver returned an unknown function,
188 * -ENODEV if the device is not active, -EINVAL if the offset is invalid.
189 * GPIOF_UNUSED if the GPIO has not been requested. Otherwise returns the
190 * function from enum gpio_func_t.
192 int gpio_get_function(struct udevice *dev, int offset, const char **namep);
195 * gpio_get_raw_function() - get the current raw function for a GPIO pin
197 * Note this does not return GPIOF_UNUSED - it will always return the GPIO
198 * driver's view of a pin function, even if it is not correctly set up.
200 * TODO(sjg@chromium.org): This should use struct gpio_desc
202 * @dev: Device to check
203 * @offset: Offset of device GPIO to check
204 * @namep: If non-NULL, this is set to the name given when the GPIO
205 * was requested, or -1 if it has not been requested
206 * @return -ENODATA if the driver returned an unknown function,
207 * -ENODEV if the device is not active, -EINVAL if the offset is invalid.
208 * Otherwise returns the function from enum gpio_func_t.
210 int gpio_get_raw_function(struct udevice *dev, int offset, const char **namep);
213 * gpio_requestf() - request a GPIO using a format string for the owner
215 * This is a helper function for gpio_request(). It allows you to provide
216 * a printf()-format string for the GPIO owner. It calls gpio_request() with
217 * the string that is created
219 int gpio_requestf(unsigned gpio, const char *fmt, ...)
220 __attribute__ ((format (__printf__, 2, 3)));
222 struct fdtdec_phandle_args;
225 * gpio_xlate_offs_flags() - implementation for common use of dm_gpio_ops.xlate
227 * This routine sets the offset field to args[0] and the flags field to
228 * GPIOD_ACTIVE_LOW if the GPIO_ACTIVE_LOW flag is present in args[1].
230 int gpio_xlate_offs_flags(struct udevice *dev, struct gpio_desc *desc,
231 struct ofnode_phandle_args *args);
234 * struct struct dm_gpio_ops - Driver model GPIO operations
236 * Refer to functions above for description. These function largely copy
239 * This is trying to be close to Linux GPIO API. Once the U-Boot uses the
240 * new DM GPIO API, this should be really easy to flip over to the Linux
241 * GPIO API-alike interface.
243 * Also it would be useful to standardise additional functions like
244 * pullup, slew rate and drive strength.
246 * gpio_request() and gpio_free() are optional - if NULL then they will
249 * Note that @offset is the offset from the base GPIO of the device. So
250 * offset 0 is the device's first GPIO and offset o-1 is the last GPIO,
251 * where o is the number of GPIO lines controlled by the device. A device
252 * is typically used to control a single bank of GPIOs. Within complex
253 * SoCs there may be many banks and therefore many devices all referring
254 * to the different IO addresses within the SoC.
256 * The uclass combines all GPIO devices together to provide a consistent
257 * numbering from 0 to n-1, where n is the number of GPIOs in total across
258 * all devices. Be careful not to confuse offset with gpio in the parameters.
261 int (*request)(struct udevice *dev, unsigned offset, const char *label);
262 int (*rfree)(struct udevice *dev, unsigned int offset);
263 int (*direction_input)(struct udevice *dev, unsigned offset);
264 int (*direction_output)(struct udevice *dev, unsigned offset,
266 int (*get_value)(struct udevice *dev, unsigned offset);
267 int (*set_value)(struct udevice *dev, unsigned offset, int value);
269 * get_function() Get the GPIO function
271 * @dev: Device to check
272 * @offset: GPIO offset within that device
273 * @return current function - GPIOF_...
275 int (*get_function)(struct udevice *dev, unsigned offset);
278 * xlate() - Translate phandle arguments into a GPIO description
280 * This function should set up the fields in desc according to the
281 * information in the arguments. The uclass will have set up:
287 * This method is optional and defaults to gpio_xlate_offs_flags,
288 * which will parse offset and the GPIO_ACTIVE_LOW flag in the first
291 * Note that @dev is passed in as a parameter to follow driver model
292 * uclass conventions, even though it is already available as
296 * @desc: Place to put GPIO description
297 * @args: Arguments provided in description
298 * @return 0 if OK, -ve on error
300 int (*xlate)(struct udevice *dev, struct gpio_desc *desc,
301 struct ofnode_phandle_args *args);
304 * set_flags() - Adjust GPIO flags
306 * This function should set up the GPIO configuration according to the
307 * information provided by @flags.
309 * If any flags cannot be set (e.g. the driver or hardware does not
310 * support them or this particular GPIO does not have the requested
311 * feature), the driver should return -EINVAL.
313 * The uclass checks that flags do not obviously conflict (e.g. input
314 * and output). If the driver finds other conflicts it should return
317 * Note that GPIOD_ACTIVE_LOW should be ignored, since the uclass
318 * adjusts for it automatically. For example, for an output GPIO,
319 * GPIOD_ACTIVE_LOW causes GPIOD_IS_OUT_ACTIVE to be inverted by the
320 * uclass, so the driver always sees the value that should be set at the
321 * pin (1=high, 0=low).
323 * This method is optional.
326 * @offset: GPIO offset within that device
327 * @flags: New flags value (GPIOD_...)
329 * @return 0 if OK, -EINVAL if unsupported, -ERECALLCONFLICT if flags
330 * conflict in some * non-obvious way and were not applied,
333 int (*set_flags)(struct udevice *dev, unsigned int offset, ulong flags);
336 * get_flags() - Get GPIO flags
338 * This function return the GPIO flags used. It should read this from
339 * the hardware directly.
341 * This method is optional.
344 * @offset: GPIO offset within that device
345 * @flagsp: place to put the current flags value
346 * @return 0 if OK, -ve on error
348 int (*get_flags)(struct udevice *dev, unsigned int offset,
351 #if CONFIG_IS_ENABLED(ACPIGEN)
353 * get_acpi() - Get the ACPI info for a GPIO
355 * This converts a GPIO to an ACPI structure for adding to the ACPI
358 * @desc: GPIO description to convert
359 * @gpio: Output ACPI GPIO information
360 * @return ACPI pin number or -ve on error
362 int (*get_acpi)(const struct gpio_desc *desc, struct acpi_gpio *gpio);
367 * struct gpio_dev_priv - information about a device used by the uclass
369 * The uclass combines all active GPIO devices into a unified numbering
370 * scheme. To do this it maintains some private information about each
373 * To implement driver model support in your GPIO driver, add a probe
374 * handler, and set @gpio_count and @bank_name correctly in that handler.
375 * This tells the uclass the name of the GPIO bank and the number of GPIOs
378 * @bank_name: Name of the GPIO device (e.g 'a' means GPIOs will be called
380 * @gpio_count: Number of GPIOs in this device
381 * @gpio_base: Base GPIO number for this device. For the first active device
382 * this will be 0; the numbering for others will follow sequentially so that
383 * @gpio_base for device 1 will equal the number of GPIOs in device 0.
384 * @name: Array of pointers to the name for each GPIO in this bank. The
385 * value of the pointer will be NULL if the GPIO has not been claimed.
387 struct gpio_dev_priv {
388 const char *bank_name;
394 /* Access the GPIO operations for a device */
395 #define gpio_get_ops(dev) ((struct dm_gpio_ops *)(dev)->driver->ops)
398 * gpio_get_bank_info - Return information about a GPIO bank/device
400 * This looks up a device and returns both its GPIO base name and the number
401 * of GPIOs it controls.
403 * @dev: Device to look up
404 * @offset_count: Returns number of GPIOs within this bank
405 * @return bank name of this device
407 const char *gpio_get_bank_info(struct udevice *dev, int *offset_count);
410 * dm_gpio_lookup_name() - Look up a named GPIO and return its description
412 * The name of a GPIO is typically its bank name followed by a number from 0.
413 * For example A0 is the first GPIO in bank A. Each bank is a separate driver
416 * @name: Name to look up
417 * @desc: Returns description, on success
418 * @return 0 if OK, -ve on error
420 int dm_gpio_lookup_name(const char *name, struct gpio_desc *desc);
423 * gpio_hog_lookup_name() - Look up a named GPIO and return the gpio descr.
425 * @name: Name to look up
426 * @desc: Returns GPIO description, on success, else NULL
427 * @return: Returns 0 if OK, else -ENODEV
429 int gpio_hog_lookup_name(const char *name, struct gpio_desc **desc);
432 * gpio_hog_probe_all() - probe all gpio devices with
435 * @return: Returns return value from device_probe()
437 int gpio_hog_probe_all(void);
440 * gpio_lookup_name - Look up a GPIO name and return its details
442 * This is used to convert a named GPIO into a device, offset and GPIO
445 * @name: GPIO name to look up
446 * @devp: Returns pointer to device which contains this GPIO
447 * @offsetp: Returns the offset number within this device
448 * @gpiop: Returns the absolute GPIO number, numbered from 0
450 int gpio_lookup_name(const char *name, struct udevice **devp,
451 unsigned int *offsetp, unsigned int *gpiop);
454 * gpio_get_values_as_int() - Turn the values of a list of GPIOs into an int
456 * This puts the value of the first GPIO into bit 0, the second into bit 1,
457 * etc. then returns the resulting integer.
459 * @gpio_list: List of GPIOs to collect
460 * @return resulting integer value, or -ve on error
462 int gpio_get_values_as_int(const int *gpio_list);
465 * dm_gpio_get_values_as_int() - Turn the values of a list of GPIOs into an int
467 * This puts the value of the first GPIO into bit 0, the second into bit 1,
468 * etc. then returns the resulting integer.
470 * @desc_list: List of GPIOs to collect
471 * @count: Number of GPIOs
472 * @return resulting integer value, or -ve on error
474 int dm_gpio_get_values_as_int(const struct gpio_desc *desc_list, int count);
477 * gpio_claim_vector() - claim a number of GPIOs for input
479 * @gpio_num_array: array of gpios to claim, terminated by -1
480 * @fmt: format string for GPIO names, e.g. "board_id%d"
481 * @return 0 if OK, -ve on error
483 int gpio_claim_vector(const int *gpio_num_array, const char *fmt);
486 * gpio_request_by_name() - Locate and request a GPIO by name
488 * This operates by looking up the given list name in the device (device
489 * tree property) and requesting the GPIO for use. The property must exist
492 * Use @flags to specify whether the GPIO should be an input or output. In
493 * principle this can also come from the device tree binding but most
494 * bindings don't provide this information. Specifically, when the GPIO uclass
495 * calls the xlate() method, it can return default flags, which are then
496 * ORed with this @flags.
498 * If we find that requesting the GPIO is not always needed we could add a
499 * new function or a new GPIOD_NO_REQUEST flag.
501 * At present driver model has no reference counting so if one device
502 * requests a GPIO which subsequently is unbound, the @desc->dev pointer
503 * will be invalid. However this will only happen if the GPIO device is
504 * unbound, not if it is removed, so this seems like a reasonable limitation
505 * for now. There is no real use case for unbinding drivers in normal
508 * The device tree binding is doc/device-tree-bindings/gpio/gpio.txt in
509 * generate terms and each specific device may add additional details in
510 * a binding file in the same directory.
512 * @dev: Device requesting the GPIO
513 * @list_name: Name of GPIO list (e.g. "board-id-gpios")
514 * @index: Index number of the GPIO in that list use request (0=first)
515 * @desc: Returns GPIO description information. If there is no such
516 * GPIO, @desc->dev will be NULL.
517 * @flags: Indicates the GPIO input/output settings (GPIOD_...)
518 * @return 0 if OK, -ENOENT if the GPIO does not exist, -EINVAL if there is
519 * something wrong with the list, or other -ve for another error (e.g.
520 * -EBUSY if a GPIO was already requested)
522 int gpio_request_by_name(struct udevice *dev, const char *list_name,
523 int index, struct gpio_desc *desc, int flags);
526 * gpio_request_list_by_name() - Request a list of GPIOs
528 * Reads all the GPIOs from a list and requests them. See
529 * gpio_request_by_name() for additional details. Lists should not be
530 * misused to hold unrelated or optional GPIOs. They should only be used
531 * for things like parallel data lines. A zero phandle terminates the list
534 * This function will either succeed, and request all GPIOs in the list, or
535 * fail and request none (it will free already-requested GPIOs in case of
536 * an error part-way through).
538 * @dev: Device requesting the GPIO
539 * @list_name: Name of GPIO list (e.g. "board-id-gpios")
540 * @desc_list: Returns a list of GPIO description information
541 * @max_count: Maximum number of GPIOs to return (@desc_list must be at least
543 * @flags: Indicates the GPIO input/output settings (GPIOD_...)
544 * @return number of GPIOs requested, or -ve on error
546 int gpio_request_list_by_name(struct udevice *dev, const char *list_name,
547 struct gpio_desc *desc_list, int max_count,
551 * dm_gpio_request() - manually request a GPIO
553 * Note: This function should only be used for testing / debugging. Instead.
554 * use gpio_request_by_name() to pull GPIOs from the device tree.
556 * @desc: GPIO description of GPIO to request (see dm_gpio_lookup_name())
557 * @label: Label to attach to the GPIO while claimed
558 * @return 0 if OK, -ve on error
560 int dm_gpio_request(struct gpio_desc *desc, const char *label);
563 * gpio_get_list_count() - Returns the number of GPIOs in a list
565 * Counts the GPIOs in a list. See gpio_request_by_name() for additional
568 * @dev: Device requesting the GPIO
569 * @list_name: Name of GPIO list (e.g. "board-id-gpios")
570 * @return number of GPIOs (0 for an empty property) or -ENOENT if the list
573 int gpio_get_list_count(struct udevice *dev, const char *list_name);
576 * gpio_request_by_name_nodev() - request GPIOs without a device
578 * This is a version of gpio_request_list_by_name() that does not use a
579 * device. Avoid it unless the caller is not yet using driver model
581 int gpio_request_by_name_nodev(ofnode node, const char *list_name, int index,
582 struct gpio_desc *desc, int flags);
585 * gpio_request_list_by_name_nodev() - request GPIOs without a device
587 * This is a version of gpio_request_list_by_name() that does not use a
588 * device. Avoid it unless the caller is not yet using driver model
590 int gpio_request_list_by_name_nodev(ofnode node, const char *list_name,
591 struct gpio_desc *desc_list, int max_count,
595 * gpio_dev_request_index() - request single GPIO from gpio device
598 * @nodename: Name of node for which gpio gets requested, used
599 * for the gpio label name
600 * @list_name: Name of GPIO list (e.g. "board-id-gpios")
601 * @index: Index number of the GPIO in that list use request (0=first)
602 * @flags: GPIOD_* flags
603 * @dtflags: GPIO flags read from DT defined see GPIOD_*
604 * @desc: returns GPIO descriptor filled from this function
605 * @return: return value from gpio_request_tail()
607 int gpio_dev_request_index(struct udevice *dev, const char *nodename,
608 char *list_name, int index, int flags,
609 int dtflags, struct gpio_desc *desc);
612 * dm_gpio_free() - Free a single GPIO
614 * This frees a single GPIOs previously returned from gpio_request_by_name().
616 * @dev: Device which requested the GPIO
617 * @desc: GPIO to free
618 * @return 0 if OK, -ve on error
620 int dm_gpio_free(struct udevice *dev, struct gpio_desc *desc);
623 * gpio_free_list() - Free a list of GPIOs
625 * This frees a list of GPIOs previously returned from
626 * gpio_request_list_by_name().
628 * @dev: Device which requested the GPIOs
629 * @desc: List of GPIOs to free
630 * @count: Number of GPIOs in the list
631 * @return 0 if OK, -ve on error
633 int gpio_free_list(struct udevice *dev, struct gpio_desc *desc, int count);
636 * gpio_free_list_nodev() - free GPIOs without a device
638 * This is a version of gpio_free_list() that does not use a
639 * device. Avoid it unless the caller is not yet using driver model
641 int gpio_free_list_nodev(struct gpio_desc *desc, int count);
644 * dm_gpio_get_value() - Get the value of a GPIO
646 * This is the driver model version of the existing gpio_get_value() function
647 * and should be used instead of that.
649 * For now, these functions have a dm_ prefix since they conflict with
652 * @desc: GPIO description containing device, offset and flags,
653 * previously returned by gpio_request_by_name()
654 * @return GPIO value (0 for inactive, 1 for active) or -ve on error
656 int dm_gpio_get_value(const struct gpio_desc *desc);
658 int dm_gpio_set_value(const struct gpio_desc *desc, int value);
661 * dm_gpio_set_dir() - Set the direction for a GPIO
663 * This sets up the direction according to the GPIO flags: desc->flags.
665 * @desc: GPIO description containing device, offset and flags,
666 * previously returned by gpio_request_by_name()
667 * @return 0 if OK, -ve on error
669 int dm_gpio_set_dir(struct gpio_desc *desc);
672 * dm_gpio_set_dir_flags() - Set direction using description and added flags
674 * This sets up the direction according to the provided flags and the GPIO
675 * description (desc->flags) which include direction information.
676 * Note that desc->flags is updated by this function.
678 * @desc: GPIO description containing device, offset and flags,
679 * previously returned by gpio_request_by_name()
680 * @flags: New flags to use
681 * @return 0 if OK, -ve on error, in which case desc->flags is not updated
683 int dm_gpio_set_dir_flags(struct gpio_desc *desc, ulong flags);
686 * dm_gpio_get_flags() - Get flags
688 * Read the current flags
690 * @desc: GPIO description containing device, offset and flags,
691 * previously returned by gpio_request_by_name()
692 * @flags: place to put the used flags
693 * @return 0 if OK, -ve on error, in which case desc->flags is not updated
695 int dm_gpio_get_flags(struct gpio_desc *desc, ulong *flags);
698 * gpio_get_number() - Get the global GPIO number of a GPIO
700 * This should only be used for debugging or interest. It returns the number
701 * that should be used for gpio_get_value() etc. to access this GPIO.
703 * @desc: GPIO description containing device, offset and flags,
704 * previously returned by gpio_request_by_name()
705 * @return GPIO number, or -ve if not found
707 int gpio_get_number(const struct gpio_desc *desc);
710 * gpio_get_acpi() - Get the ACPI pin for a GPIO
712 * This converts a GPIO to an ACPI pin number for adding to the ACPI
713 * tables. If the GPIO is invalid, the pin_count and pins[0] are set to 0
715 * @desc: GPIO description to convert
716 * @gpio: Output ACPI GPIO information
717 * @return ACPI pin number or -ve on error
719 int gpio_get_acpi(const struct gpio_desc *desc, struct acpi_gpio *gpio);
722 * devm_gpiod_get_index - Resource-managed gpiod_get()
723 * @dev: GPIO consumer
724 * @con_id: function within the GPIO consumer
725 * @index: index of the GPIO to obtain in the consumer
726 * @flags: optional GPIO initialization flags
728 * Managed gpiod_get(). GPIO descriptors returned from this function are
729 * automatically disposed on device unbind.
730 * Return the GPIO descriptor corresponding to the function con_id of device
731 * dev, -ENOENT if no GPIO has been assigned to the requested function, or
732 * another IS_ERR() code if an error occurred while trying to acquire the GPIO.
734 struct gpio_desc *devm_gpiod_get_index(struct udevice *dev, const char *id,
735 unsigned int index, int flags);
737 #define devm_gpiod_get(dev, id, flags) devm_gpiod_get_index(dev, id, 0, flags)
739 * gpiod_get_optional - obtain an optional GPIO for a given GPIO function
740 * @dev: GPIO consumer, can be NULL for system-global GPIOs
741 * @con_id: function within the GPIO consumer
742 * @index: index of the GPIO to obtain in the consumer
743 * @flags: optional GPIO initialization flags
745 * This is equivalent to devm_gpiod_get(), except that when no GPIO was
746 * assigned to the requested function it will return NULL. This is convenient
747 * for drivers that need to handle optional GPIOs.
749 struct gpio_desc *devm_gpiod_get_index_optional(struct udevice *dev,
754 #define devm_gpiod_get_optional(dev, id, flags) \
755 devm_gpiod_get_index_optional(dev, id, 0, flags)
758 * devm_gpiod_put - Resource-managed gpiod_put()
759 * @dev: GPIO consumer
760 * @desc: GPIO descriptor to dispose of
762 * Dispose of a GPIO descriptor obtained with devm_gpiod_get() or
763 * devm_gpiod_get_index(). Normally this function will not be called as the GPIO
764 * will be disposed of by the resource management code.
766 void devm_gpiod_put(struct udevice *dev, struct gpio_desc *desc);
768 #endif /* _ASM_GENERIC_GPIO_H_ */