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.
38 * @deprecated Please use driver model instead
39 * Request a GPIO. This should be called before any of the other functions
40 * are used on this GPIO.
42 * Note: With driver model, the label is allocated so there is no need for
43 * the caller to preserve it.
45 * @param gpio GPIO number
46 * @param label User label for this GPIO
47 * @return 0 if ok, -1 on error
49 int gpio_request(unsigned gpio, const char *label);
52 * @deprecated Please use driver model instead
53 * Stop using the GPIO. This function should not alter pin configuration.
55 * @param gpio GPIO number
56 * @return 0 if ok, -1 on error
58 int gpio_free(unsigned gpio);
61 * @deprecated Please use driver model instead
62 * Make a GPIO an input.
64 * @param gpio GPIO number
65 * @return 0 if ok, -1 on error
67 int gpio_direction_input(unsigned gpio);
70 * @deprecated Please use driver model instead
71 * Make a GPIO an output, and set its value.
73 * @param gpio GPIO number
74 * @param value GPIO value (0 for low or 1 for high)
75 * @return 0 if ok, -1 on error
77 int gpio_direction_output(unsigned gpio, int value);
80 * @deprecated Please use driver model instead
81 * Get a GPIO's value. This will work whether the GPIO is an input
84 * @param gpio GPIO number
85 * @return 0 if low, 1 if high, -1 on error
87 int gpio_get_value(unsigned gpio);
90 * @deprecated Please use driver model instead
91 * Set an output GPIO's value. The GPIO must already be an output or
92 * this function may have no effect.
94 * @param gpio GPIO number
95 * @param value GPIO value (0 for low or 1 for high)
96 * @return 0 if ok, -1 on error
98 int gpio_set_value(unsigned gpio, int value);
100 /* State of a GPIO, as reported by get_function() */
104 GPIOF_UNUSED, /* Not claimed */
105 GPIOF_UNKNOWN, /* Not known */
106 GPIOF_FUNC, /* Not used as a GPIO */
114 struct udevice *dev; /* Device, NULL for invalid GPIO */
116 #define GPIOD_REQUESTED (1 << 0) /* Requested/claimed */
117 #define GPIOD_IS_OUT (1 << 1) /* GPIO is an output */
118 #define GPIOD_IS_IN (1 << 2) /* GPIO is an input */
119 #define GPIOD_ACTIVE_LOW (1 << 3) /* value has active low */
120 #define GPIOD_IS_OUT_ACTIVE (1 << 4) /* set output active */
122 uint offset; /* GPIO offset within the device */
124 * We could consider adding the GPIO label in here. Possibly we could
125 * use this structure for internal GPIO information.
130 * dm_gpio_is_valid() - Check if a GPIO is valid
132 * @desc: GPIO description containing device, offset and flags,
133 * previously returned by gpio_request_by_name()
134 * @return true if valid, false if not
136 static inline bool dm_gpio_is_valid(const struct gpio_desc *desc)
138 return desc->dev != NULL;
142 * gpio_get_status() - get the current GPIO status as a string
144 * Obtain the current GPIO status as a string which can be presented to the
145 * user. A typical string is:
147 * "b4: in: 1 [x] sdmmc_cd"
149 * which means this is GPIO bank b, offset 4, currently set to input, current
150 * value 1, [x] means that it is requested and the owner is 'sdmmc_cd'
152 * TODO(sjg@chromium.org): This should use struct gpio_desc
154 * @dev: Device to check
155 * @offset: Offset of device GPIO to check
156 * @buf: Place to put string
157 * @buffsize: Size of string including \0
159 int gpio_get_status(struct udevice *dev, int offset, char *buf, int buffsize);
162 * gpio_get_function() - get the current function for a GPIO pin
164 * Note this returns GPIOF_UNUSED if the GPIO is not requested.
166 * TODO(sjg@chromium.org): This should use struct gpio_desc
168 * @dev: Device to check
169 * @offset: Offset of device GPIO to check
170 * @namep: If non-NULL, this is set to the name given when the GPIO
171 * was requested, or -1 if it has not been requested
172 * @return -ENODATA if the driver returned an unknown function,
173 * -ENODEV if the device is not active, -EINVAL if the offset is invalid.
174 * GPIOF_UNUSED if the GPIO has not been requested. Otherwise returns the
175 * function from enum gpio_func_t.
177 int gpio_get_function(struct udevice *dev, int offset, const char **namep);
180 * gpio_get_raw_function() - get the current raw function for a GPIO pin
182 * Note this does not return GPIOF_UNUSED - it will always return the GPIO
183 * driver's view of a pin function, even if it is not correctly set up.
185 * TODO(sjg@chromium.org): This should use struct gpio_desc
187 * @dev: Device to check
188 * @offset: Offset of device GPIO to check
189 * @namep: If non-NULL, this is set to the name given when the GPIO
190 * was requested, or -1 if it has not been requested
191 * @return -ENODATA if the driver returned an unknown function,
192 * -ENODEV if the device is not active, -EINVAL if the offset is invalid.
193 * Otherwise returns the function from enum gpio_func_t.
195 int gpio_get_raw_function(struct udevice *dev, int offset, const char **namep);
198 * gpio_requestf() - request a GPIO using a format string for the owner
200 * This is a helper function for gpio_request(). It allows you to provide
201 * a printf()-format string for the GPIO owner. It calls gpio_request() with
202 * the string that is created
204 int gpio_requestf(unsigned gpio, const char *fmt, ...)
205 __attribute__ ((format (__printf__, 2, 3)));
207 struct fdtdec_phandle_args;
210 * gpio_xlate_offs_flags() - implementation for common use of dm_gpio_ops.xlate
212 * This routine sets the offset field to args[0] and the flags field to
213 * GPIOD_ACTIVE_LOW if the GPIO_ACTIVE_LOW flag is present in args[1].
216 int gpio_xlate_offs_flags(struct udevice *dev, struct gpio_desc *desc,
217 struct fdtdec_phandle_args *args);
220 * struct struct dm_gpio_ops - Driver model GPIO operations
222 * Refer to functions above for description. These function largely copy
225 * This is trying to be close to Linux GPIO API. Once the U-Boot uses the
226 * new DM GPIO API, this should be really easy to flip over to the Linux
227 * GPIO API-alike interface.
229 * Also it would be useful to standardise additional functions like
230 * pullup, slew rate and drive strength.
232 * gpio_request() and gpio_free() are optional - if NULL then they will
235 * Note that @offset is the offset from the base GPIO of the device. So
236 * offset 0 is the device's first GPIO and offset o-1 is the last GPIO,
237 * where o is the number of GPIO lines controlled by the device. A device
238 * is typically used to control a single bank of GPIOs. Within complex
239 * SoCs there may be many banks and therefore many devices all referring
240 * to the different IO addresses within the SoC.
242 * The uclass combines all GPIO devices together to provide a consistent
243 * numbering from 0 to n-1, where n is the number of GPIOs in total across
244 * all devices. Be careful not to confuse offset with gpio in the parameters.
247 int (*request)(struct udevice *dev, unsigned offset, const char *label);
248 int (*free)(struct udevice *dev, unsigned offset);
249 int (*direction_input)(struct udevice *dev, unsigned offset);
250 int (*direction_output)(struct udevice *dev, unsigned offset,
252 int (*get_value)(struct udevice *dev, unsigned offset);
253 int (*set_value)(struct udevice *dev, unsigned offset, int value);
255 * get_function() Get the GPIO function
257 * @dev: Device to check
258 * @offset: GPIO offset within that device
259 * @return current function - GPIOF_...
261 int (*get_function)(struct udevice *dev, unsigned offset);
264 * xlate() - Translate phandle arguments into a GPIO description
266 * This function should set up the fields in desc according to the
267 * information in the arguments. The uclass will have set up:
273 * This method is optional and defaults to gpio_xlate_offs_flags,
274 * which will parse offset and the GPIO_ACTIVE_LOW flag in the first
277 * Note that @dev is passed in as a parameter to follow driver model
278 * uclass conventions, even though it is already available as
282 * @desc: Place to put GPIO description
283 * @args: Arguments provided in description
284 * @return 0 if OK, -ve on error
286 int (*xlate)(struct udevice *dev, struct gpio_desc *desc,
287 struct fdtdec_phandle_args *args);
291 * struct gpio_dev_priv - information about a device used by the uclass
293 * The uclass combines all active GPIO devices into a unified numbering
294 * scheme. To do this it maintains some private information about each
297 * To implement driver model support in your GPIO driver, add a probe
298 * handler, and set @gpio_count and @bank_name correctly in that handler.
299 * This tells the uclass the name of the GPIO bank and the number of GPIOs
302 * @bank_name: Name of the GPIO device (e.g 'a' means GPIOs will be called
304 * @gpio_count: Number of GPIOs in this device
305 * @gpio_base: Base GPIO number for this device. For the first active device
306 * this will be 0; the numbering for others will follow sequentially so that
307 * @gpio_base for device 1 will equal the number of GPIOs in device 0.
308 * @name: Array of pointers to the name for each GPIO in this bank. The
309 * value of the pointer will be NULL if the GPIO has not been claimed.
311 struct gpio_dev_priv {
312 const char *bank_name;
318 /* Access the GPIO operations for a device */
319 #define gpio_get_ops(dev) ((struct dm_gpio_ops *)(dev)->driver->ops)
322 * gpio_get_bank_info - Return information about a GPIO bank/device
324 * This looks up a device and returns both its GPIO base name and the number
325 * of GPIOs it controls.
327 * @dev: Device to look up
328 * @offset_count: Returns number of GPIOs within this bank
329 * @return bank name of this device
331 const char *gpio_get_bank_info(struct udevice *dev, int *offset_count);
334 * dm_gpio_lookup_name() - Look up a named GPIO and return its description
336 * The name of a GPIO is typically its bank name followed by a number from 0.
337 * For example A0 is the first GPIO in bank A. Each bank is a separate driver
340 * @name: Name to look up
341 * @desc: Returns description, on success
342 * @return 0 if OK, -ve on error
344 int dm_gpio_lookup_name(const char *name, struct gpio_desc *desc);
347 * gpio_lookup_name - Look up a GPIO name and return its details
349 * This is used to convert a named GPIO into a device, offset and GPIO
352 * @name: GPIO name to look up
353 * @devp: Returns pointer to device which contains this GPIO
354 * @offsetp: Returns the offset number within this device
355 * @gpiop: Returns the absolute GPIO number, numbered from 0
357 int gpio_lookup_name(const char *name, struct udevice **devp,
358 unsigned int *offsetp, unsigned int *gpiop);
361 * gpio_get_values_as_int() - Turn the values of a list of GPIOs into an int
363 * This puts the value of the first GPIO into bit 0, the second into bit 1,
364 * etc. then returns the resulting integer.
366 * @gpio_list: List of GPIOs to collect
367 * @return resulting integer value, or -ve on error
369 int gpio_get_values_as_int(const int *gpio_list);
372 * dm_gpio_get_values_as_int() - Turn the values of a list of GPIOs into an int
374 * This puts the value of the first GPIO into bit 0, the second into bit 1,
375 * etc. then returns the resulting integer.
377 * @desc_list: List of GPIOs to collect
378 * @count: Number of GPIOs
379 * @return resulting integer value, or -ve on error
381 int dm_gpio_get_values_as_int(const struct gpio_desc *desc_list, int count);
384 * gpio_claim_vector() - claim a number of GPIOs for input
386 * @gpio_num_array: array of gpios to claim, terminated by -1
387 * @fmt: format string for GPIO names, e.g. "board_id%d"
388 * @return 0 if OK, -ve on error
390 int gpio_claim_vector(const int *gpio_num_array, const char *fmt);
393 * gpio_request_by_name() - Locate and request a GPIO by name
395 * This operates by looking up the given list name in the device (device
396 * tree property) and requesting the GPIO for use. The property must exist
399 * Use @flags to specify whether the GPIO should be an input or output. In
400 * principle this can also come from the device tree binding but most
401 * bindings don't provide this information. Specifically, when the GPIO uclass
402 * calls the xlate() method, it can return default flags, which are then
403 * ORed with this @flags.
405 * If we find that requesting the GPIO is not always needed we could add a
406 * new function or a new GPIOD_NO_REQUEST flag.
408 * At present driver model has no reference counting so if one device
409 * requests a GPIO which subsequently is unbound, the @desc->dev pointer
410 * will be invalid. However this will only happen if the GPIO device is
411 * unbound, not if it is removed, so this seems like a reasonable limitation
412 * for now. There is no real use case for unbinding drivers in normal
415 * The device tree binding is doc/device-tree-bindings/gpio/gpio.txt in
416 * generate terms and each specific device may add additional details in
417 * a binding file in the same directory.
419 * @dev: Device requesting the GPIO
420 * @list_name: Name of GPIO list (e.g. "board-id-gpios")
421 * @index: Index number of the GPIO in that list use request (0=first)
422 * @desc: Returns GPIO description information. If there is no such
423 * GPIO, dev->dev will be NULL.
424 * @flags: Indicates the GPIO input/output settings (GPIOD_...)
425 * @return 0 if OK, -ENOENT if the GPIO does not exist, -EINVAL if there is
426 * something wrong with the list, or other -ve for another error (e.g.
427 * -EBUSY if a GPIO was already requested)
429 int gpio_request_by_name(struct udevice *dev, const char *list_name,
430 int index, struct gpio_desc *desc, int flags);
433 * gpio_request_list_by_name() - Request a list of GPIOs
435 * Reads all the GPIOs from a list and requests them. See
436 * gpio_request_by_name() for additional details. Lists should not be
437 * misused to hold unrelated or optional GPIOs. They should only be used
438 * for things like parallel data lines. A zero phandle terminates the list
441 * This function will either succeed, and request all GPIOs in the list, or
442 * fail and request none (it will free already-requested GPIOs in case of
443 * an error part-way through).
445 * @dev: Device requesting the GPIO
446 * @list_name: Name of GPIO list (e.g. "board-id-gpios")
447 * @desc_list: Returns a list of GPIO description information
448 * @max_count: Maximum number of GPIOs to return (@desc_list must be at least
450 * @flags: Indicates the GPIO input/output settings (GPIOD_...)
451 * @return number of GPIOs requested, or -ve on error
453 int gpio_request_list_by_name(struct udevice *dev, const char *list_name,
454 struct gpio_desc *desc_list, int max_count,
458 * dm_gpio_request() - manually request a GPIO
460 * Note: This function should only be used for testing / debugging. Instead.
461 * use gpio_request_by_name() to pull GPIOs from the device tree.
463 * @desc: GPIO description of GPIO to request (see dm_gpio_lookup_name())
464 * @label: Label to attach to the GPIO while claimed
465 * @return 0 if OK, -ve on error
467 int dm_gpio_request(struct gpio_desc *desc, const char *label);
470 * gpio_get_list_count() - Returns the number of GPIOs in a list
472 * Counts the GPIOs in a list. See gpio_request_by_name() for additional
475 * @dev: Device requesting the GPIO
476 * @list_name: Name of GPIO list (e.g. "board-id-gpios")
477 * @return number of GPIOs (0 for an empty property) or -ENOENT if the list
480 int gpio_get_list_count(struct udevice *dev, const char *list_name);
483 * gpio_request_by_name_nodev() - request GPIOs without a device
485 * This is a version of gpio_request_list_by_name() that does not use a
486 * device. Avoid it unless the caller is not yet using driver model
488 int gpio_request_by_name_nodev(const void *blob, int node,
489 const char *list_name,
490 int index, struct gpio_desc *desc, int flags);
493 * gpio_request_list_by_name_nodev() - request GPIOs without a device
495 * This is a version of gpio_request_list_by_name() that does not use a
496 * device. Avoid it unless the caller is not yet using driver model
498 int gpio_request_list_by_name_nodev(const void *blob, int node,
499 const char *list_name,
500 struct gpio_desc *desc_list, int max_count,
504 * dm_gpio_free() - Free a single GPIO
506 * This frees a single GPIOs previously returned from gpio_request_by_name().
508 * @dev: Device which requested the GPIO
509 * @desc: GPIO to free
510 * @return 0 if OK, -ve on error
512 int dm_gpio_free(struct udevice *dev, struct gpio_desc *desc);
515 * gpio_free_list() - Free a list of GPIOs
517 * This frees a list of GPIOs previously returned from
518 * gpio_request_list_by_name().
520 * @dev: Device which requested the GPIOs
521 * @desc: List of GPIOs to free
522 * @count: Number of GPIOs in the list
523 * @return 0 if OK, -ve on error
525 int gpio_free_list(struct udevice *dev, struct gpio_desc *desc, int count);
528 * gpio_free_list_nodev() - free GPIOs without a device
530 * This is a version of gpio_free_list() that does not use a
531 * device. Avoid it unless the caller is not yet using driver model
533 int gpio_free_list_nodev(struct gpio_desc *desc, int count);
536 * dm_gpio_get_value() - Get the value of a GPIO
538 * This is the driver model version of the existing gpio_get_value() function
539 * and should be used instead of that.
541 * For now, these functions have a dm_ prefix since they conflict with
544 * @desc: GPIO description containing device, offset and flags,
545 * previously returned by gpio_request_by_name()
546 * @return GPIO value (0 for inactive, 1 for active) or -ve on error
548 int dm_gpio_get_value(const struct gpio_desc *desc);
550 int dm_gpio_set_value(const struct gpio_desc *desc, int value);
553 * dm_gpio_set_dir() - Set the direction for a GPIO
555 * This sets up the direction according tot the provided flags. It will do
556 * nothing unless the direction is actually specified.
558 * @desc: GPIO description containing device, offset and flags,
559 * previously returned by gpio_request_by_name()
560 * @return 0 if OK, -ve on error
562 int dm_gpio_set_dir(struct gpio_desc *desc);
565 * dm_gpio_set_dir_flags() - Set direction using specific flags
567 * This is like dm_gpio_set_dir() except that the flags value is provided
568 * instead of being used from desc->flags. This is needed because in many
569 * cases the GPIO description does not include direction information.
570 * Note that desc->flags is updated by this function.
572 * @desc: GPIO description containing device, offset and flags,
573 * previously returned by gpio_request_by_name()
574 * @flags: New flags to use
575 * @return 0 if OK, -ve on error, in which case desc->flags is not updated
577 int dm_gpio_set_dir_flags(struct gpio_desc *desc, ulong flags);
580 * gpio_get_number() - Get the global GPIO number of a GPIO
582 * This should only be used for debugging or interest. It returns the number
583 * that should be used for gpio_get_value() etc. to access this GPIO.
585 * @desc: GPIO description containing device, offset and flags,
586 * previously returned by gpio_request_by_name()
587 * @return GPIO number, or -ve if not found
589 int gpio_get_number(const struct gpio_desc *desc);
591 #endif /* _ASM_GENERIC_GPIO_H_ */