2 * Copyright (c) 2011 The Chromium OS Authors.
3 * Copyright (c) 2011, NVIDIA Corp. All rights reserved.
4 * SPDX-License-Identifier: GPL-2.0+
7 #ifndef _ASM_GENERIC_GPIO_H_
8 #define _ASM_GENERIC_GPIO_H_
11 * Generic GPIO API for U-Boot
14 * NB: This is deprecated. Please use the driver model functions instead:
16 * - gpio_request_by_name()
17 * - dm_gpio_get_value() etc.
19 * For now we need a dm_ prefix on some functions to avoid name collision.
22 * GPIOs are numbered from 0 to GPIO_COUNT-1 which value is defined
23 * by the SOC/architecture.
25 * Each GPIO can be an input or output. If an input then its value can
26 * be read as 0 or 1. If an output then its value can be set to 0 or 1.
27 * If you try to write an input then the value is undefined. If you try
28 * to read an output, barring something very unusual, you will get
29 * back the value of the output that you previously set.
31 * In some cases the operation may fail, for example if the GPIO number
32 * is out of range, or the GPIO is not available because its pin is
33 * being used by another function. In that case, functions may return
34 * an error value of -1.
39 GPIOFLAG_OUTPUT_INIT_LOW,
40 GPIOFLAG_OUTPUT_INIT_HIGH,
45 enum gpio_flags flags;
50 * @deprecated Please use driver model instead
51 * Request a GPIO. This should be called before any of the other functions
52 * are used on this GPIO.
54 * Note: With driver model, the label is allocated so there is no need for
55 * the caller to preserve it.
57 * @param gpio GPIO number
58 * @param label User label for this GPIO
59 * @return 0 if ok, -1 on error
61 int gpio_request(unsigned gpio, const char *label);
64 * @deprecated Please use driver model instead
65 * Stop using the GPIO. This function should not alter pin configuration.
67 * @param gpio GPIO number
68 * @return 0 if ok, -1 on error
70 int gpio_free(unsigned gpio);
73 * @deprecated Please use driver model instead
74 * Make a GPIO an input.
76 * @param gpio GPIO number
77 * @return 0 if ok, -1 on error
79 int gpio_direction_input(unsigned gpio);
82 * @deprecated Please use driver model instead
83 * Make a GPIO an output, and set its value.
85 * @param gpio GPIO number
86 * @param value GPIO value (0 for low or 1 for high)
87 * @return 0 if ok, -1 on error
89 int gpio_direction_output(unsigned gpio, int value);
92 * @deprecated Please use driver model instead
93 * Get a GPIO's value. This will work whether the GPIO is an input
96 * @param gpio GPIO number
97 * @return 0 if low, 1 if high, -1 on error
99 int gpio_get_value(unsigned gpio);
102 * @deprecated Please use driver model instead
103 * Set an output GPIO's value. The GPIO must already be an output or
104 * this function may have no effect.
106 * @param gpio GPIO number
107 * @param value GPIO value (0 for low or 1 for high)
108 * @return 0 if ok, -1 on error
110 int gpio_set_value(unsigned gpio, int value);
112 /* State of a GPIO, as reported by get_function() */
116 GPIOF_UNUSED, /* Not claimed */
117 GPIOF_UNKNOWN, /* Not known */
118 GPIOF_FUNC, /* Not used as a GPIO */
126 struct udevice *dev; /* Device, NULL for invalid GPIO */
128 #define GPIOD_REQUESTED (1 << 0) /* Requested/claimed */
129 #define GPIOD_IS_OUT (1 << 1) /* GPIO is an output */
130 #define GPIOD_IS_IN (1 << 2) /* GPIO is an input */
131 #define GPIOD_ACTIVE_LOW (1 << 3) /* value has active low */
132 #define GPIOD_IS_OUT_ACTIVE (1 << 4) /* set output active */
134 uint offset; /* GPIO offset within the device */
136 * We could consider adding the GPIO label in here. Possibly we could
137 * use this structure for internal GPIO information.
142 * dm_gpio_is_valid() - Check if a GPIO is valid
144 * @desc: GPIO description containing device, offset and flags,
145 * previously returned by gpio_request_by_name()
146 * @return true if valid, false if not
148 static inline bool dm_gpio_is_valid(struct gpio_desc *desc)
150 return desc->dev != NULL;
154 * gpio_get_status() - get the current GPIO status as a string
156 * Obtain the current GPIO status as a string which can be presented to the
157 * user. A typical string is:
159 * "b4: in: 1 [x] sdmmc_cd"
161 * which means this is GPIO bank b, offset 4, currently set to input, current
162 * value 1, [x] means that it is requested and the owner is 'sdmmc_cd'
164 * TODO(sjg@chromium.org): This should use struct gpio_desc
166 * @dev: Device to check
167 * @offset: Offset of device GPIO to check
168 * @buf: Place to put string
169 * @buffsize: Size of string including \0
171 int gpio_get_status(struct udevice *dev, int offset, char *buf, int buffsize);
174 * gpio_get_function() - get the current function for a GPIO pin
176 * Note this returns GPIOF_UNUSED if the GPIO is not requested.
178 * TODO(sjg@chromium.org): This should use struct gpio_desc
180 * @dev: Device to check
181 * @offset: Offset of device GPIO to check
182 * @namep: If non-NULL, this is set to the name given when the GPIO
183 * was requested, or -1 if it has not been requested
184 * @return -ENODATA if the driver returned an unknown function,
185 * -ENODEV if the device is not active, -EINVAL if the offset is invalid.
186 * GPIOF_UNUSED if the GPIO has not been requested. Otherwise returns the
187 * function from enum gpio_func_t.
189 int gpio_get_function(struct udevice *dev, int offset, const char **namep);
192 * gpio_get_raw_function() - get the current raw function for a GPIO pin
194 * Note this does not return GPIOF_UNUSED - it will always return the GPIO
195 * driver's view of a pin function, even if it is not correctly set up.
197 * TODO(sjg@chromium.org): This should use struct gpio_desc
199 * @dev: Device to check
200 * @offset: Offset of device GPIO to check
201 * @namep: If non-NULL, this is set to the name given when the GPIO
202 * was requested, or -1 if it has not been requested
203 * @return -ENODATA if the driver returned an unknown function,
204 * -ENODEV if the device is not active, -EINVAL if the offset is invalid.
205 * Otherwise returns the function from enum gpio_func_t.
207 int gpio_get_raw_function(struct udevice *dev, int offset, const char **namep);
210 * gpio_requestf() - request a GPIO using a format string for the owner
212 * This is a helper function for gpio_request(). It allows you to provide
213 * a printf()-format string for the GPIO owner. It calls gpio_request() with
214 * the string that is created
216 int gpio_requestf(unsigned gpio, const char *fmt, ...)
217 __attribute__ ((format (__printf__, 2, 3)));
219 struct fdtdec_phandle_args;
222 * struct struct dm_gpio_ops - Driver model GPIO operations
224 * Refer to functions above for description. These function largely copy
227 * This is trying to be close to Linux GPIO API. Once the U-Boot uses the
228 * new DM GPIO API, this should be really easy to flip over to the Linux
229 * GPIO API-alike interface.
231 * Also it would be useful to standardise additional functions like
232 * pullup, slew rate and drive strength.
234 * gpio_request() and gpio_free() are optional - if NULL then they will
237 * Note that @offset is the offset from the base GPIO of the device. So
238 * offset 0 is the device's first GPIO and offset o-1 is the last GPIO,
239 * where o is the number of GPIO lines controlled by the device. A device
240 * is typically used to control a single bank of GPIOs. Within complex
241 * SoCs there may be many banks and therefore many devices all referring
242 * to the different IO addresses within the SoC.
244 * The uclass combines all GPIO devices together to provide a consistent
245 * numbering from 0 to n-1, where n is the number of GPIOs in total across
246 * all devices. Be careful not to confuse offset with gpio in the parameters.
249 int (*request)(struct udevice *dev, unsigned offset, const char *label);
250 int (*free)(struct udevice *dev, unsigned offset);
251 int (*direction_input)(struct udevice *dev, unsigned offset);
252 int (*direction_output)(struct udevice *dev, unsigned offset,
254 int (*get_value)(struct udevice *dev, unsigned offset);
255 int (*set_value)(struct udevice *dev, unsigned offset, int value);
257 * get_function() Get the GPIO function
259 * @dev: Device to check
260 * @offset: GPIO offset within that device
261 * @return current function - GPIOF_...
263 int (*get_function)(struct udevice *dev, unsigned offset);
266 * xlate() - Translate phandle arguments into a GPIO description
268 * This function should set up the fields in desc according to the
269 * information in the arguments. The uclass will have set up:
273 * @desc->offset to the value of the first argument in args, if any,
274 * otherwise -1 (which is invalid)
276 * This method is optional so if the above defaults suit it can be
277 * omitted. Typical behaviour is to set up the GPIOD_ACTIVE_LOW flag
280 * Note that @dev is passed in as a parameter to follow driver model
281 * uclass conventions, even though it is already available as
285 * @desc: Place to put GPIO description
286 * @args: Arguments provided in description
287 * @return 0 if OK, -ve on error
289 int (*xlate)(struct udevice *dev, struct gpio_desc *desc,
290 struct fdtdec_phandle_args *args);
294 * struct gpio_dev_priv - information about a device used by the uclass
296 * The uclass combines all active GPIO devices into a unified numbering
297 * scheme. To do this it maintains some private information about each
300 * To implement driver model support in your GPIO driver, add a probe
301 * handler, and set @gpio_count and @bank_name correctly in that handler.
302 * This tells the uclass the name of the GPIO bank and the number of GPIOs
305 * @bank_name: Name of the GPIO device (e.g 'a' means GPIOs will be called
307 * @gpio_count: Number of GPIOs in this device
308 * @gpio_base: Base GPIO number for this device. For the first active device
309 * this will be 0; the numbering for others will follow sequentially so that
310 * @gpio_base for device 1 will equal the number of GPIOs in device 0.
311 * @name: Array of pointers to the name for each GPIO in this bank. The
312 * value of the pointer will be NULL if the GPIO has not been claimed.
314 struct gpio_dev_priv {
315 const char *bank_name;
321 /* Access the GPIO operations for a device */
322 #define gpio_get_ops(dev) ((struct dm_gpio_ops *)(dev)->driver->ops)
325 * gpio_get_bank_info - Return information about a GPIO bank/device
327 * This looks up a device and returns both its GPIO base name and the number
328 * of GPIOs it controls.
330 * @dev: Device to look up
331 * @offset_count: Returns number of GPIOs within this bank
332 * @return bank name of this device
334 const char *gpio_get_bank_info(struct udevice *dev, int *offset_count);
337 * dm_gpio_lookup_name() - Look up a named GPIO and return its description
339 * The name of a GPIO is typically its bank name followed by a number from 0.
340 * For example A0 is the first GPIO in bank A. Each bank is a separate driver
343 * @name: Name to look up
344 * @desc: Returns description, on success
345 * @return 0 if OK, -ve on error
347 int dm_gpio_lookup_name(const char *name, struct gpio_desc *desc);
350 * gpio_lookup_name - Look up a GPIO name and return its details
352 * This is used to convert a named GPIO into a device, offset and GPIO
355 * @name: GPIO name to look up
356 * @devp: Returns pointer to device which contains this GPIO
357 * @offsetp: Returns the offset number within this device
358 * @gpiop: Returns the absolute GPIO number, numbered from 0
360 int gpio_lookup_name(const char *name, struct udevice **devp,
361 unsigned int *offsetp, unsigned int *gpiop);
364 * gpio_get_values_as_int() - Turn the values of a list of GPIOs into an int
366 * This puts the value of the first GPIO into bit 0, the second into bit 1,
367 * etc. then returns the resulting integer.
369 * @gpio_list: List of GPIOs to collect
370 * @return resulting integer value, or -ve on error
372 int gpio_get_values_as_int(const int *gpio_list);
375 * gpio_claim_vector() - claim a number of GPIOs for input
377 * @gpio_num_array: array of gpios to claim, terminated by -1
378 * @fmt: format string for GPIO names, e.g. "board_id%d"
379 * @return 0 if OK, -ve on error
381 int gpio_claim_vector(const int *gpio_num_array, const char *fmt);
384 * gpio_request_by_name() - Locate and request a GPIO by name
386 * This operates by looking up the given list name in the device (device
387 * tree property) and requesting the GPIO for use. The property must exist
390 * Use @flags to specify whether the GPIO should be an input or output. In
391 * principle this can also come from the device tree binding but most
392 * bindings don't provide this information. Specifically, when the GPIO uclass
393 * calls the xlate() method, it can return default flags, which are then
394 * ORed with this @flags.
396 * If we find that requesting the GPIO is not always needed we could add a
397 * new function or a new GPIOD_NO_REQUEST flag.
399 * At present driver model has no reference counting so if one device
400 * requests a GPIO which subsequently is unbound, the @desc->dev pointer
401 * will be invalid. However this will only happen if the GPIO device is
402 * unbound, not if it is removed, so this seems like a reasonable limitation
403 * for now. There is no real use case for unbinding drivers in normal
406 * The device tree binding is doc/device-tree-bindings/gpio/gpio.txt in
407 * generate terms and each specific device may add additional details in
408 * a binding file in the same directory.
410 * @dev: Device requesting the GPIO
411 * @list_name: Name of GPIO list (e.g. "board-id-gpios")
412 * @index: Index number of the GPIO in that list use request (0=first)
413 * @desc: Returns GPIO description information. If there is no such
414 * GPIO, dev->dev will be NULL.
415 * @flags: Indicates the GPIO input/output settings (GPIOD_...)
416 * @return 0 if OK, -ENOENT if the GPIO does not exist, -EINVAL if there is
417 * something wrong with the list, or other -ve for another error (e.g.
418 * -EBUSY if a GPIO was already requested)
420 int gpio_request_by_name(struct udevice *dev, const char *list_name,
421 int index, struct gpio_desc *desc, int flags);
424 * gpio_request_list_by_name() - Request a list of GPIOs
426 * Reads all the GPIOs from a list and requests them. See
427 * gpio_request_by_name() for additional details. Lists should not be
428 * misused to hold unrelated or optional GPIOs. They should only be used
429 * for things like parallel data lines. A zero phandle terminates the list
432 * This function will either succeed, and request all GPIOs in the list, or
433 * fail and request none (it will free already-requested GPIOs in case of
434 * an error part-way through).
436 * @dev: Device requesting the GPIO
437 * @list_name: Name of GPIO list (e.g. "board-id-gpios")
438 * @desc_list: Returns a list of GPIO description information
439 * @max_count: Maximum number of GPIOs to return (@desc_list must be at least
441 * @flags: Indicates the GPIO input/output settings (GPIOD_...)
442 * @return number of GPIOs requested, or -ve on error
444 int gpio_request_list_by_name(struct udevice *dev, const char *list_name,
445 struct gpio_desc *desc_list, int max_count,
449 * dm_gpio_request() - manually request a GPIO
451 * Note: This function should only be used for testing / debugging. Instead.
452 * use gpio_request_by_name() to pull GPIOs from the device tree.
454 * @desc: GPIO description of GPIO to request (see dm_gpio_lookup_name())
455 * @label: Label to attach to the GPIO while claimed
456 * @return 0 if OK, -ve on error
458 int dm_gpio_request(struct gpio_desc *desc, const char *label);
461 * gpio_get_list_count() - Returns the number of GPIOs in a list
463 * Counts the GPIOs in a list. See gpio_request_by_name() for additional
466 * @dev: Device requesting the GPIO
467 * @list_name: Name of GPIO list (e.g. "board-id-gpios")
468 * @return number of GPIOs (0 for an empty property) or -ENOENT if the list
471 int gpio_get_list_count(struct udevice *dev, const char *list_name);
474 * gpio_request_by_name_nodev() - request GPIOs without a device
476 * This is a version of gpio_request_list_by_name() that does not use a
477 * device. Avoid it unless the caller is not yet using driver model
479 int gpio_request_by_name_nodev(const void *blob, int node,
480 const char *list_name,
481 int index, struct gpio_desc *desc, int flags);
484 * gpio_request_list_by_name_nodev() - request GPIOs without a device
486 * This is a version of gpio_request_list_by_name() that does not use a
487 * device. Avoid it unless the caller is not yet using driver model
489 int gpio_request_list_by_name_nodev(const void *blob, int node,
490 const char *list_name,
491 struct gpio_desc *desc_list, int max_count,
495 * dm_gpio_free() - Free a single GPIO
497 * This frees a single GPIOs previously returned from gpio_request_by_name().
499 * @dev: Device which requested the GPIO
500 * @desc: GPIO to free
501 * @return 0 if OK, -ve on error
503 int dm_gpio_free(struct udevice *dev, struct gpio_desc *desc);
506 * gpio_free_list() - Free a list of GPIOs
508 * This frees a list of GPIOs previously returned from
509 * gpio_request_list_by_name().
511 * @dev: Device which requested the GPIOs
512 * @desc: List of GPIOs to free
513 * @count: Number of GPIOs in the list
514 * @return 0 if OK, -ve on error
516 int gpio_free_list(struct udevice *dev, struct gpio_desc *desc, int count);
519 * gpio_free_list_nodev() - free GPIOs without a device
521 * This is a version of gpio_free_list() that does not use a
522 * device. Avoid it unless the caller is not yet using driver model
524 int gpio_free_list_nodev(struct gpio_desc *desc, int count);
527 * dm_gpio_get_value() - Get the value of a GPIO
529 * This is the driver model version of the existing gpio_get_value() function
530 * and should be used instead of that.
532 * For now, these functions have a dm_ prefix since they conflict with
535 * @desc: GPIO description containing device, offset and flags,
536 * previously returned by gpio_request_by_name()
537 * @return GPIO value (0 for inactive, 1 for active) or -ve on error
539 int dm_gpio_get_value(struct gpio_desc *desc);
541 int dm_gpio_set_value(struct gpio_desc *desc, int value);
544 * dm_gpio_set_dir() - Set the direction for a GPIO
546 * This sets up the direction according tot the provided flags. It will do
547 * nothing unless the direction is actually specified.
549 * @desc: GPIO description containing device, offset and flags,
550 * previously returned by gpio_request_by_name()
551 * @return 0 if OK, -ve on error
553 int dm_gpio_set_dir(struct gpio_desc *desc);
556 * dm_gpio_set_dir_flags() - Set direction using specific flags
558 * This is like dm_gpio_set_dir() except that the flags value is provided
559 * instead of being used from desc->flags. This is needed because in many
560 * cases the GPIO description does not include direction information.
561 * Note that desc->flags is updated by this function.
563 * @desc: GPIO description containing device, offset and flags,
564 * previously returned by gpio_request_by_name()
565 * @flags: New flags to use
566 * @return 0 if OK, -ve on error, in which case desc->flags is not updated
568 int dm_gpio_set_dir_flags(struct gpio_desc *desc, ulong flags);
571 * gpio_get_number() - Get the global GPIO number of a GPIO
573 * This should only be used for debugging or interest. It returns the number
574 * that should be used for gpio_get_value() etc. to access this GPIO.
576 * @desc: GPIO description containing device, offset and flags,
577 * previously returned by gpio_request_by_name()
578 * @return GPIO number, or -ve if not found
580 int gpio_get_number(struct gpio_desc *desc);
583 * @deprecated Please use driver model instead
584 * Request a GPIO and configure it
585 * @param gpios pointer to array of gpio defs
586 * @param count number of GPIOs to set up
588 static inline int gpio_request_one(unsigned int gpio, enum gpio_flags flags,
593 ret = gpio_request(gpio, label);
597 if (flags == GPIOFLAG_INPUT)
598 gpio_direction_input(gpio);
599 else if (flags == GPIOFLAG_OUTPUT_INIT_LOW)
600 gpio_direction_output(gpio, 0);
601 else if (flags == GPIOFLAG_OUTPUT_INIT_HIGH)
602 gpio_direction_output(gpio, 1);
608 * Request a set of GPIOs and configure them
609 * @param gpios pointer to array of gpio defs
610 * @param count number of GPIOs to set up
612 static inline int gpio_request_array(const struct gpio *gpios, int count)
617 for (i = 0; i < count; i++) {
618 ret = gpio_request_one(gpios[i].gpio, gpios[i].flags,
621 printf("Failed to request GPIO%d (%u of %u): %d\n",
622 gpios[i].gpio, i, count, ret);
630 gpio_free(gpios[i].gpio);
636 * @deprecated Please use driver model instead
637 * Release a set of GPIOs
638 * @param gpios pointer to array of gpio defs
639 * @param count number of GPIOs to set up
641 static inline int gpio_free_array(const struct gpio *gpios, int count)
646 for (i = 0; i < count; i++)
647 ret |= gpio_free(gpios[i].gpio);
651 #endif /* _ASM_GENERIC_GPIO_H_ */