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_
10 struct ofnode_phandle_args;
13 * Generic GPIO API for U-Boot
16 * NB: This is deprecated. Please use the driver model functions instead:
18 * - gpio_request_by_name()
19 * - dm_gpio_get_value() etc.
21 * For now we need a dm_ prefix on some functions to avoid name collision.
24 * GPIOs are numbered from 0 to GPIO_COUNT-1 which value is defined
25 * by the SOC/architecture.
27 * Each GPIO can be an input or output. If an input then its value can
28 * be read as 0 or 1. If an output then its value can be set to 0 or 1.
29 * If you try to write an input then the value is undefined. If you try
30 * to read an output, barring something very unusual, you will get
31 * back the value of the output that you previously set.
33 * In some cases the operation may fail, for example if the GPIO number
34 * is out of range, or the GPIO is not available because its pin is
35 * being used by another function. In that case, functions may return
36 * an error value of -1.
40 * @deprecated Please use driver model instead
41 * Request a GPIO. This should be called before any of the other functions
42 * are used on this GPIO.
44 * Note: With driver model, the label is allocated so there is no need for
45 * the caller to preserve it.
47 * @param gpio GPIO number
48 * @param label User label for this GPIO
49 * @return 0 if ok, -1 on error
51 int gpio_request(unsigned gpio, const char *label);
54 * @deprecated Please use driver model instead
55 * Stop using the GPIO. This function should not alter pin configuration.
57 * @param gpio GPIO number
58 * @return 0 if ok, -1 on error
60 int gpio_free(unsigned gpio);
63 * @deprecated Please use driver model instead
64 * Make a GPIO an input.
66 * @param gpio GPIO number
67 * @return 0 if ok, -1 on error
69 int gpio_direction_input(unsigned gpio);
72 * @deprecated Please use driver model instead
73 * Make a GPIO an output, and set its value.
75 * @param gpio GPIO number
76 * @param value GPIO value (0 for low or 1 for high)
77 * @return 0 if ok, -1 on error
79 int gpio_direction_output(unsigned gpio, int value);
82 * @deprecated Please use driver model instead
83 * Get a GPIO's value. This will work whether the GPIO is an input
86 * @param gpio GPIO number
87 * @return 0 if low, 1 if high, -1 on error
89 int gpio_get_value(unsigned gpio);
92 * @deprecated Please use driver model instead
93 * Set an output GPIO's value. The GPIO must already be an output or
94 * this function may have no effect.
96 * @param gpio GPIO number
97 * @param value GPIO value (0 for low or 1 for high)
98 * @return 0 if ok, -1 on error
100 int gpio_set_value(unsigned gpio, int value);
102 /* State of a GPIO, as reported by get_function() */
106 GPIOF_UNUSED, /* Not claimed */
107 GPIOF_UNKNOWN, /* Not known */
108 GPIOF_FUNC, /* Not used as a GPIO */
116 struct udevice *dev; /* Device, NULL for invalid GPIO */
118 #define GPIOD_REQUESTED (1 << 0) /* Requested/claimed */
119 #define GPIOD_IS_OUT (1 << 1) /* GPIO is an output */
120 #define GPIOD_IS_IN (1 << 2) /* GPIO is an input */
121 #define GPIOD_ACTIVE_LOW (1 << 3) /* value has active low */
122 #define GPIOD_IS_OUT_ACTIVE (1 << 4) /* set output active */
124 uint offset; /* GPIO offset within the device */
126 * We could consider adding the GPIO label in here. Possibly we could
127 * use this structure for internal GPIO information.
132 * dm_gpio_is_valid() - Check if a GPIO is valid
134 * @desc: GPIO description containing device, offset and flags,
135 * previously returned by gpio_request_by_name()
136 * @return true if valid, false if not
138 static inline bool dm_gpio_is_valid(const struct gpio_desc *desc)
140 return desc->dev != NULL;
144 * gpio_get_status() - get the current GPIO status as a string
146 * Obtain the current GPIO status as a string which can be presented to the
147 * user. A typical string is:
149 * "b4: in: 1 [x] sdmmc_cd"
151 * which means this is GPIO bank b, offset 4, currently set to input, current
152 * value 1, [x] means that it is requested and the owner is 'sdmmc_cd'
154 * TODO(sjg@chromium.org): This should use struct gpio_desc
156 * @dev: Device to check
157 * @offset: Offset of device GPIO to check
158 * @buf: Place to put string
159 * @buffsize: Size of string including \0
161 int gpio_get_status(struct udevice *dev, int offset, char *buf, int buffsize);
164 * gpio_get_function() - get the current function for a GPIO pin
166 * Note this returns GPIOF_UNUSED if the GPIO is not requested.
168 * TODO(sjg@chromium.org): This should use struct gpio_desc
170 * @dev: Device to check
171 * @offset: Offset of device GPIO to check
172 * @namep: If non-NULL, this is set to the name given when the GPIO
173 * was requested, or -1 if it has not been requested
174 * @return -ENODATA if the driver returned an unknown function,
175 * -ENODEV if the device is not active, -EINVAL if the offset is invalid.
176 * GPIOF_UNUSED if the GPIO has not been requested. Otherwise returns the
177 * function from enum gpio_func_t.
179 int gpio_get_function(struct udevice *dev, int offset, const char **namep);
182 * gpio_get_raw_function() - get the current raw function for a GPIO pin
184 * Note this does not return GPIOF_UNUSED - it will always return the GPIO
185 * driver's view of a pin function, even if it is not correctly set up.
187 * TODO(sjg@chromium.org): This should use struct gpio_desc
189 * @dev: Device to check
190 * @offset: Offset of device GPIO to check
191 * @namep: If non-NULL, this is set to the name given when the GPIO
192 * was requested, or -1 if it has not been requested
193 * @return -ENODATA if the driver returned an unknown function,
194 * -ENODEV if the device is not active, -EINVAL if the offset is invalid.
195 * Otherwise returns the function from enum gpio_func_t.
197 int gpio_get_raw_function(struct udevice *dev, int offset, const char **namep);
200 * gpio_requestf() - request a GPIO using a format string for the owner
202 * This is a helper function for gpio_request(). It allows you to provide
203 * a printf()-format string for the GPIO owner. It calls gpio_request() with
204 * the string that is created
206 int gpio_requestf(unsigned gpio, const char *fmt, ...)
207 __attribute__ ((format (__printf__, 2, 3)));
209 struct fdtdec_phandle_args;
212 * gpio_xlate_offs_flags() - implementation for common use of dm_gpio_ops.xlate
214 * This routine sets the offset field to args[0] and the flags field to
215 * GPIOD_ACTIVE_LOW if the GPIO_ACTIVE_LOW flag is present in args[1].
218 int gpio_xlate_offs_flags(struct udevice *dev, struct gpio_desc *desc,
219 struct ofnode_phandle_args *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);
256 int (*get_open_drain)(struct udevice *dev, unsigned offset);
257 int (*set_open_drain)(struct udevice *dev, unsigned offset, int value);
259 * get_function() Get the GPIO function
261 * @dev: Device to check
262 * @offset: GPIO offset within that device
263 * @return current function - GPIOF_...
265 int (*get_function)(struct udevice *dev, unsigned offset);
268 * xlate() - Translate phandle arguments into a GPIO description
270 * This function should set up the fields in desc according to the
271 * information in the arguments. The uclass will have set up:
277 * This method is optional and defaults to gpio_xlate_offs_flags,
278 * which will parse offset and the GPIO_ACTIVE_LOW flag in the first
281 * Note that @dev is passed in as a parameter to follow driver model
282 * uclass conventions, even though it is already available as
286 * @desc: Place to put GPIO description
287 * @args: Arguments provided in description
288 * @return 0 if OK, -ve on error
290 int (*xlate)(struct udevice *dev, struct gpio_desc *desc,
291 struct ofnode_phandle_args *args);
295 * struct gpio_dev_priv - information about a device used by the uclass
297 * The uclass combines all active GPIO devices into a unified numbering
298 * scheme. To do this it maintains some private information about each
301 * To implement driver model support in your GPIO driver, add a probe
302 * handler, and set @gpio_count and @bank_name correctly in that handler.
303 * This tells the uclass the name of the GPIO bank and the number of GPIOs
306 * @bank_name: Name of the GPIO device (e.g 'a' means GPIOs will be called
308 * @gpio_count: Number of GPIOs in this device
309 * @gpio_base: Base GPIO number for this device. For the first active device
310 * this will be 0; the numbering for others will follow sequentially so that
311 * @gpio_base for device 1 will equal the number of GPIOs in device 0.
312 * @name: Array of pointers to the name for each GPIO in this bank. The
313 * value of the pointer will be NULL if the GPIO has not been claimed.
315 struct gpio_dev_priv {
316 const char *bank_name;
322 /* Access the GPIO operations for a device */
323 #define gpio_get_ops(dev) ((struct dm_gpio_ops *)(dev)->driver->ops)
326 * gpio_get_bank_info - Return information about a GPIO bank/device
328 * This looks up a device and returns both its GPIO base name and the number
329 * of GPIOs it controls.
331 * @dev: Device to look up
332 * @offset_count: Returns number of GPIOs within this bank
333 * @return bank name of this device
335 const char *gpio_get_bank_info(struct udevice *dev, int *offset_count);
338 * dm_gpio_lookup_name() - Look up a named GPIO and return its description
340 * The name of a GPIO is typically its bank name followed by a number from 0.
341 * For example A0 is the first GPIO in bank A. Each bank is a separate driver
344 * @name: Name to look up
345 * @desc: Returns description, on success
346 * @return 0 if OK, -ve on error
348 int dm_gpio_lookup_name(const char *name, struct gpio_desc *desc);
351 * gpio_lookup_name - Look up a GPIO name and return its details
353 * This is used to convert a named GPIO into a device, offset and GPIO
356 * @name: GPIO name to look up
357 * @devp: Returns pointer to device which contains this GPIO
358 * @offsetp: Returns the offset number within this device
359 * @gpiop: Returns the absolute GPIO number, numbered from 0
361 int gpio_lookup_name(const char *name, struct udevice **devp,
362 unsigned int *offsetp, unsigned int *gpiop);
365 * gpio_get_values_as_int() - Turn the values of a list of GPIOs into an int
367 * This puts the value of the first GPIO into bit 0, the second into bit 1,
368 * etc. then returns the resulting integer.
370 * @gpio_list: List of GPIOs to collect
371 * @return resulting integer value, or -ve on error
373 int gpio_get_values_as_int(const int *gpio_list);
376 * dm_gpio_get_values_as_int() - Turn the values of a list of GPIOs into an int
378 * This puts the value of the first GPIO into bit 0, the second into bit 1,
379 * etc. then returns the resulting integer.
381 * @desc_list: List of GPIOs to collect
382 * @count: Number of GPIOs
383 * @return resulting integer value, or -ve on error
385 int dm_gpio_get_values_as_int(const struct gpio_desc *desc_list, int count);
388 * gpio_claim_vector() - claim a number of GPIOs for input
390 * @gpio_num_array: array of gpios to claim, terminated by -1
391 * @fmt: format string for GPIO names, e.g. "board_id%d"
392 * @return 0 if OK, -ve on error
394 int gpio_claim_vector(const int *gpio_num_array, const char *fmt);
397 * gpio_request_by_name() - Locate and request a GPIO by name
399 * This operates by looking up the given list name in the device (device
400 * tree property) and requesting the GPIO for use. The property must exist
403 * Use @flags to specify whether the GPIO should be an input or output. In
404 * principle this can also come from the device tree binding but most
405 * bindings don't provide this information. Specifically, when the GPIO uclass
406 * calls the xlate() method, it can return default flags, which are then
407 * ORed with this @flags.
409 * If we find that requesting the GPIO is not always needed we could add a
410 * new function or a new GPIOD_NO_REQUEST flag.
412 * At present driver model has no reference counting so if one device
413 * requests a GPIO which subsequently is unbound, the @desc->dev pointer
414 * will be invalid. However this will only happen if the GPIO device is
415 * unbound, not if it is removed, so this seems like a reasonable limitation
416 * for now. There is no real use case for unbinding drivers in normal
419 * The device tree binding is doc/device-tree-bindings/gpio/gpio.txt in
420 * generate terms and each specific device may add additional details in
421 * a binding file in the same directory.
423 * @dev: Device requesting the GPIO
424 * @list_name: Name of GPIO list (e.g. "board-id-gpios")
425 * @index: Index number of the GPIO in that list use request (0=first)
426 * @desc: Returns GPIO description information. If there is no such
427 * GPIO, dev->dev will be NULL.
428 * @flags: Indicates the GPIO input/output settings (GPIOD_...)
429 * @return 0 if OK, -ENOENT if the GPIO does not exist, -EINVAL if there is
430 * something wrong with the list, or other -ve for another error (e.g.
431 * -EBUSY if a GPIO was already requested)
433 int gpio_request_by_name(struct udevice *dev, const char *list_name,
434 int index, struct gpio_desc *desc, int flags);
437 * gpio_request_list_by_name() - Request a list of GPIOs
439 * Reads all the GPIOs from a list and requests them. See
440 * gpio_request_by_name() for additional details. Lists should not be
441 * misused to hold unrelated or optional GPIOs. They should only be used
442 * for things like parallel data lines. A zero phandle terminates the list
445 * This function will either succeed, and request all GPIOs in the list, or
446 * fail and request none (it will free already-requested GPIOs in case of
447 * an error part-way through).
449 * @dev: Device requesting the GPIO
450 * @list_name: Name of GPIO list (e.g. "board-id-gpios")
451 * @desc_list: Returns a list of GPIO description information
452 * @max_count: Maximum number of GPIOs to return (@desc_list must be at least
454 * @flags: Indicates the GPIO input/output settings (GPIOD_...)
455 * @return number of GPIOs requested, or -ve on error
457 int gpio_request_list_by_name(struct udevice *dev, const char *list_name,
458 struct gpio_desc *desc_list, int max_count,
462 * dm_gpio_request() - manually request a GPIO
464 * Note: This function should only be used for testing / debugging. Instead.
465 * use gpio_request_by_name() to pull GPIOs from the device tree.
467 * @desc: GPIO description of GPIO to request (see dm_gpio_lookup_name())
468 * @label: Label to attach to the GPIO while claimed
469 * @return 0 if OK, -ve on error
471 int dm_gpio_request(struct gpio_desc *desc, const char *label);
474 * gpio_get_list_count() - Returns the number of GPIOs in a list
476 * Counts the GPIOs in a list. See gpio_request_by_name() for additional
479 * @dev: Device requesting the GPIO
480 * @list_name: Name of GPIO list (e.g. "board-id-gpios")
481 * @return number of GPIOs (0 for an empty property) or -ENOENT if the list
484 int gpio_get_list_count(struct udevice *dev, const char *list_name);
487 * gpio_request_by_name_nodev() - request GPIOs without a device
489 * This is a version of gpio_request_list_by_name() that does not use a
490 * device. Avoid it unless the caller is not yet using driver model
492 int gpio_request_by_name_nodev(const void *blob, int node,
493 const char *list_name,
494 int index, struct gpio_desc *desc, int flags);
497 * gpio_request_list_by_name_nodev() - request GPIOs without a device
499 * This is a version of gpio_request_list_by_name() that does not use a
500 * device. Avoid it unless the caller is not yet using driver model
502 int gpio_request_list_by_name_nodev(const void *blob, int node,
503 const char *list_name,
504 struct gpio_desc *desc_list, int max_count,
508 * dm_gpio_free() - Free a single GPIO
510 * This frees a single GPIOs previously returned from gpio_request_by_name().
512 * @dev: Device which requested the GPIO
513 * @desc: GPIO to free
514 * @return 0 if OK, -ve on error
516 int dm_gpio_free(struct udevice *dev, struct gpio_desc *desc);
519 * gpio_free_list() - Free a list of GPIOs
521 * This frees a list of GPIOs previously returned from
522 * gpio_request_list_by_name().
524 * @dev: Device which requested the GPIOs
525 * @desc: List of GPIOs to free
526 * @count: Number of GPIOs in the list
527 * @return 0 if OK, -ve on error
529 int gpio_free_list(struct udevice *dev, struct gpio_desc *desc, int count);
532 * gpio_free_list_nodev() - free GPIOs without a device
534 * This is a version of gpio_free_list() that does not use a
535 * device. Avoid it unless the caller is not yet using driver model
537 int gpio_free_list_nodev(struct gpio_desc *desc, int count);
540 * dm_gpio_get_value() - Get the value of a GPIO
542 * This is the driver model version of the existing gpio_get_value() function
543 * and should be used instead of that.
545 * For now, these functions have a dm_ prefix since they conflict with
548 * @desc: GPIO description containing device, offset and flags,
549 * previously returned by gpio_request_by_name()
550 * @return GPIO value (0 for inactive, 1 for active) or -ve on error
552 int dm_gpio_get_value(const struct gpio_desc *desc);
554 int dm_gpio_set_value(const struct gpio_desc *desc, int value);
557 * dm_gpio_get_open_drain() - Check if open-drain-mode of a GPIO is active
559 * This checks if open-drain-mode for a GPIO is enabled or not. This method is
562 * @desc: GPIO description containing device, offset and flags,
563 * previously returned by gpio_request_by_name()
564 * @return Value of open drain mode for GPIO (0 for inactive, 1 for active) or
567 int dm_gpio_get_open_drain(struct gpio_desc *desc);
570 * dm_gpio_set_open_drain() - Switch open-drain-mode of a GPIO on or off
572 * This enables or disables open-drain mode for a GPIO. This method is
573 * optional; if the driver does not support it, nothing happens when the method
576 * In open-drain mode, instead of actively driving the output (Push-pull
577 * output), the GPIO's pin is connected to the collector (for a NPN transistor)
578 * or the drain (for a MOSFET) of a transistor, respectively. The pin then
579 * either forms an open circuit or a connection to ground, depending on the
580 * state of the transistor.
582 * @desc: GPIO description containing device, offset and flags,
583 * previously returned by gpio_request_by_name()
584 * @return 0 if OK, -ve on error
586 int dm_gpio_set_open_drain(struct gpio_desc *desc, int value);
589 * dm_gpio_set_dir() - Set the direction for a GPIO
591 * This sets up the direction according tot the provided flags. It will do
592 * nothing unless the direction is actually specified.
594 * @desc: GPIO description containing device, offset and flags,
595 * previously returned by gpio_request_by_name()
596 * @return 0 if OK, -ve on error
598 int dm_gpio_set_dir(struct gpio_desc *desc);
601 * dm_gpio_set_dir_flags() - Set direction using specific flags
603 * This is like dm_gpio_set_dir() except that the flags value is provided
604 * instead of being used from desc->flags. This is needed because in many
605 * cases the GPIO description does not include direction information.
606 * Note that desc->flags is updated by this function.
608 * @desc: GPIO description containing device, offset and flags,
609 * previously returned by gpio_request_by_name()
610 * @flags: New flags to use
611 * @return 0 if OK, -ve on error, in which case desc->flags is not updated
613 int dm_gpio_set_dir_flags(struct gpio_desc *desc, ulong flags);
616 * gpio_get_number() - Get the global GPIO number of a GPIO
618 * This should only be used for debugging or interest. It returns the number
619 * that should be used for gpio_get_value() etc. to access this GPIO.
621 * @desc: GPIO description containing device, offset and flags,
622 * previously returned by gpio_request_by_name()
623 * @return GPIO number, or -ve if not found
625 int gpio_get_number(const struct gpio_desc *desc);
627 #endif /* _ASM_GENERIC_GPIO_H_ */