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>
12 struct ofnode_phandle_args;
15 * Generic GPIO API for U-Boot
18 * NB: This is deprecated. Please use the driver model functions instead:
20 * - gpio_request_by_name()
21 * - dm_gpio_get_value() etc.
23 * For now we need a dm_ prefix on some functions to avoid name collision.
26 * GPIOs are numbered from 0 to GPIO_COUNT-1 which value is defined
27 * by the SOC/architecture.
29 * Each GPIO can be an input or output. If an input then its value can
30 * be read as 0 or 1. If an output then its value can be set to 0 or 1.
31 * If you try to write an input then the value is undefined. If you try
32 * to read an output, barring something very unusual, you will get
33 * back the value of the output that you previously set.
35 * In some cases the operation may fail, for example if the GPIO number
36 * is out of range, or the GPIO is not available because its pin is
37 * being used by another function. In that case, functions may return
38 * an error value of -1.
42 * @deprecated Please use driver model instead
43 * Request a GPIO. This should be called before any of the other functions
44 * are used on this GPIO.
46 * Note: With driver model, the label is allocated so there is no need for
47 * the caller to preserve it.
49 * @param gpio GPIO number
50 * @param label User label for this GPIO
51 * @return 0 if ok, -1 on error
53 int gpio_request(unsigned gpio, const char *label);
56 * @deprecated Please use driver model instead
57 * Stop using the GPIO. This function should not alter pin configuration.
59 * @param gpio GPIO number
60 * @return 0 if ok, -1 on error
62 int gpio_free(unsigned gpio);
65 * @deprecated Please use driver model instead
66 * Make a GPIO an input.
68 * @param gpio GPIO number
69 * @return 0 if ok, -1 on error
71 int gpio_direction_input(unsigned gpio);
74 * @deprecated Please use driver model instead
75 * Make a GPIO an output, and set its value.
77 * @param gpio GPIO number
78 * @param value GPIO value (0 for low or 1 for high)
79 * @return 0 if ok, -1 on error
81 int gpio_direction_output(unsigned gpio, int value);
84 * @deprecated Please use driver model instead
85 * Get a GPIO's value. This will work whether the GPIO is an input
88 * @param gpio GPIO number
89 * @return 0 if low, 1 if high, -1 on error
91 int gpio_get_value(unsigned gpio);
94 * @deprecated Please use driver model instead
95 * Set an output GPIO's value. The GPIO must already be an output or
96 * this function may have no effect.
98 * @param gpio GPIO number
99 * @param value GPIO value (0 for low or 1 for high)
100 * @return 0 if ok, -1 on error
102 int gpio_set_value(unsigned gpio, int value);
104 /* State of a GPIO, as reported by get_function() */
108 GPIOF_UNUSED, /* Not claimed */
109 GPIOF_UNKNOWN, /* Not known */
110 GPIOF_FUNC, /* Not used as a GPIO */
118 struct udevice *dev; /* Device, NULL for invalid GPIO */
120 #define GPIOD_IS_OUT BIT(1) /* GPIO is an output */
121 #define GPIOD_IS_IN BIT(2) /* GPIO is an input */
122 #define GPIOD_ACTIVE_LOW BIT(3) /* value has active low */
123 #define GPIOD_IS_OUT_ACTIVE BIT(4) /* set output active */
125 uint offset; /* GPIO offset within the device */
127 * We could consider adding the GPIO label in here. Possibly we could
128 * use this structure for internal GPIO information.
133 * dm_gpio_is_valid() - Check if a GPIO is valid
135 * @desc: GPIO description containing device, offset and flags,
136 * previously returned by gpio_request_by_name()
137 * @return true if valid, false if not
139 static inline bool dm_gpio_is_valid(const struct gpio_desc *desc)
141 return desc->dev != NULL;
145 * gpio_get_status() - get the current GPIO status as a string
147 * Obtain the current GPIO status as a string which can be presented to the
148 * user. A typical string is:
150 * "b4: in: 1 [x] sdmmc_cd"
152 * which means this is GPIO bank b, offset 4, currently set to input, current
153 * value 1, [x] means that it is requested and the owner is 'sdmmc_cd'
155 * TODO(sjg@chromium.org): This should use struct gpio_desc
157 * @dev: Device to check
158 * @offset: Offset of device GPIO to check
159 * @buf: Place to put string
160 * @buffsize: Size of string including \0
162 int gpio_get_status(struct udevice *dev, int offset, char *buf, int buffsize);
165 * gpio_get_function() - get the current function for a GPIO pin
167 * Note this returns GPIOF_UNUSED if the GPIO is not requested.
169 * TODO(sjg@chromium.org): This should use struct gpio_desc
171 * @dev: Device to check
172 * @offset: Offset of device GPIO to check
173 * @namep: If non-NULL, this is set to the name given when the GPIO
174 * was requested, or -1 if it has not been requested
175 * @return -ENODATA if the driver returned an unknown function,
176 * -ENODEV if the device is not active, -EINVAL if the offset is invalid.
177 * GPIOF_UNUSED if the GPIO has not been requested. Otherwise returns the
178 * function from enum gpio_func_t.
180 int gpio_get_function(struct udevice *dev, int offset, const char **namep);
183 * gpio_get_raw_function() - get the current raw function for a GPIO pin
185 * Note this does not return GPIOF_UNUSED - it will always return the GPIO
186 * driver's view of a pin function, even if it is not correctly set up.
188 * TODO(sjg@chromium.org): This should use struct gpio_desc
190 * @dev: Device to check
191 * @offset: Offset of device GPIO to check
192 * @namep: If non-NULL, this is set to the name given when the GPIO
193 * was requested, or -1 if it has not been requested
194 * @return -ENODATA if the driver returned an unknown function,
195 * -ENODEV if the device is not active, -EINVAL if the offset is invalid.
196 * Otherwise returns the function from enum gpio_func_t.
198 int gpio_get_raw_function(struct udevice *dev, int offset, const char **namep);
201 * gpio_requestf() - request a GPIO using a format string for the owner
203 * This is a helper function for gpio_request(). It allows you to provide
204 * a printf()-format string for the GPIO owner. It calls gpio_request() with
205 * the string that is created
207 int gpio_requestf(unsigned gpio, const char *fmt, ...)
208 __attribute__ ((format (__printf__, 2, 3)));
210 struct fdtdec_phandle_args;
213 * gpio_xlate_offs_flags() - implementation for common use of dm_gpio_ops.xlate
215 * This routine sets the offset field to args[0] and the flags field to
216 * 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 (*rfree)(struct udevice *dev, unsigned int 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_hog_lookup_name() - Look up a named GPIO and return the gpio descr.
353 * @name: Name to look up
354 * @desc: Returns GPIO description, on success, else NULL
355 * @return: Returns 0 if OK, else -ENODEV
357 int gpio_hog_lookup_name(const char *name, struct gpio_desc **desc);
360 * gpio_hog_probe_all() - probe all gpio devices with
363 * @return: Returns return value from device_probe()
365 int gpio_hog_probe_all(void);
368 * gpio_lookup_name - Look up a GPIO name and return its details
370 * This is used to convert a named GPIO into a device, offset and GPIO
373 * @name: GPIO name to look up
374 * @devp: Returns pointer to device which contains this GPIO
375 * @offsetp: Returns the offset number within this device
376 * @gpiop: Returns the absolute GPIO number, numbered from 0
378 int gpio_lookup_name(const char *name, struct udevice **devp,
379 unsigned int *offsetp, unsigned int *gpiop);
382 * gpio_get_values_as_int() - Turn the values of a list of GPIOs into an int
384 * This puts the value of the first GPIO into bit 0, the second into bit 1,
385 * etc. then returns the resulting integer.
387 * @gpio_list: List of GPIOs to collect
388 * @return resulting integer value, or -ve on error
390 int gpio_get_values_as_int(const int *gpio_list);
393 * dm_gpio_get_values_as_int() - Turn the values of a list of GPIOs into an int
395 * This puts the value of the first GPIO into bit 0, the second into bit 1,
396 * etc. then returns the resulting integer.
398 * @desc_list: List of GPIOs to collect
399 * @count: Number of GPIOs
400 * @return resulting integer value, or -ve on error
402 int dm_gpio_get_values_as_int(const struct gpio_desc *desc_list, int count);
405 * gpio_claim_vector() - claim a number of GPIOs for input
407 * @gpio_num_array: array of gpios to claim, terminated by -1
408 * @fmt: format string for GPIO names, e.g. "board_id%d"
409 * @return 0 if OK, -ve on error
411 int gpio_claim_vector(const int *gpio_num_array, const char *fmt);
414 * gpio_request_by_name() - Locate and request a GPIO by name
416 * This operates by looking up the given list name in the device (device
417 * tree property) and requesting the GPIO for use. The property must exist
420 * Use @flags to specify whether the GPIO should be an input or output. In
421 * principle this can also come from the device tree binding but most
422 * bindings don't provide this information. Specifically, when the GPIO uclass
423 * calls the xlate() method, it can return default flags, which are then
424 * ORed with this @flags.
426 * If we find that requesting the GPIO is not always needed we could add a
427 * new function or a new GPIOD_NO_REQUEST flag.
429 * At present driver model has no reference counting so if one device
430 * requests a GPIO which subsequently is unbound, the @desc->dev pointer
431 * will be invalid. However this will only happen if the GPIO device is
432 * unbound, not if it is removed, so this seems like a reasonable limitation
433 * for now. There is no real use case for unbinding drivers in normal
436 * The device tree binding is doc/device-tree-bindings/gpio/gpio.txt in
437 * generate terms and each specific device may add additional details in
438 * a binding file in the same directory.
440 * @dev: Device requesting the GPIO
441 * @list_name: Name of GPIO list (e.g. "board-id-gpios")
442 * @index: Index number of the GPIO in that list use request (0=first)
443 * @desc: Returns GPIO description information. If there is no such
444 * GPIO, dev->dev will be NULL.
445 * @flags: Indicates the GPIO input/output settings (GPIOD_...)
446 * @return 0 if OK, -ENOENT if the GPIO does not exist, -EINVAL if there is
447 * something wrong with the list, or other -ve for another error (e.g.
448 * -EBUSY if a GPIO was already requested)
450 int gpio_request_by_name(struct udevice *dev, const char *list_name,
451 int index, struct gpio_desc *desc, int flags);
454 * gpio_request_list_by_name() - Request a list of GPIOs
456 * Reads all the GPIOs from a list and requests them. See
457 * gpio_request_by_name() for additional details. Lists should not be
458 * misused to hold unrelated or optional GPIOs. They should only be used
459 * for things like parallel data lines. A zero phandle terminates the list
462 * This function will either succeed, and request all GPIOs in the list, or
463 * fail and request none (it will free already-requested GPIOs in case of
464 * an error part-way through).
466 * @dev: Device requesting the GPIO
467 * @list_name: Name of GPIO list (e.g. "board-id-gpios")
468 * @desc_list: Returns a list of GPIO description information
469 * @max_count: Maximum number of GPIOs to return (@desc_list must be at least
471 * @flags: Indicates the GPIO input/output settings (GPIOD_...)
472 * @return number of GPIOs requested, or -ve on error
474 int gpio_request_list_by_name(struct udevice *dev, const char *list_name,
475 struct gpio_desc *desc_list, int max_count,
479 * dm_gpio_request() - manually request a GPIO
481 * Note: This function should only be used for testing / debugging. Instead.
482 * use gpio_request_by_name() to pull GPIOs from the device tree.
484 * @desc: GPIO description of GPIO to request (see dm_gpio_lookup_name())
485 * @label: Label to attach to the GPIO while claimed
486 * @return 0 if OK, -ve on error
488 int dm_gpio_request(struct gpio_desc *desc, const char *label);
491 * gpio_get_list_count() - Returns the number of GPIOs in a list
493 * Counts the GPIOs in a list. See gpio_request_by_name() for additional
496 * @dev: Device requesting the GPIO
497 * @list_name: Name of GPIO list (e.g. "board-id-gpios")
498 * @return number of GPIOs (0 for an empty property) or -ENOENT if the list
501 int gpio_get_list_count(struct udevice *dev, const char *list_name);
504 * gpio_request_by_name_nodev() - request GPIOs without a device
506 * This is a version of gpio_request_list_by_name() that does not use a
507 * device. Avoid it unless the caller is not yet using driver model
509 int gpio_request_by_name_nodev(ofnode node, const char *list_name, int index,
510 struct gpio_desc *desc, int flags);
513 * gpio_request_list_by_name_nodev() - request GPIOs without a device
515 * This is a version of gpio_request_list_by_name() that does not use a
516 * device. Avoid it unless the caller is not yet using driver model
518 int gpio_request_list_by_name_nodev(ofnode node, const char *list_name,
519 struct gpio_desc *desc_list, int max_count,
523 * gpio_dev_request_index() - request single GPIO from gpio device
526 * @nodename: Name of node for which gpio gets requested, used
527 * for the gpio label name
528 * @list_name: Name of GPIO list (e.g. "board-id-gpios")
529 * @index: Index number of the GPIO in that list use request (0=first)
530 * @flags: GPIOD_* flags
531 * @dtflags: GPIO flags read from DT defined see GPIOD_*
532 * @desc: returns GPIO descriptor filled from this function
533 * @return: return value from gpio_request_tail()
535 int gpio_dev_request_index(struct udevice *dev, const char *nodename,
536 char *list_name, int index, int flags,
537 int dtflags, struct gpio_desc *desc);
540 * dm_gpio_free() - Free a single GPIO
542 * This frees a single GPIOs previously returned from gpio_request_by_name().
544 * @dev: Device which requested the GPIO
545 * @desc: GPIO to free
546 * @return 0 if OK, -ve on error
548 int dm_gpio_free(struct udevice *dev, struct gpio_desc *desc);
551 * gpio_free_list() - Free a list of GPIOs
553 * This frees a list of GPIOs previously returned from
554 * gpio_request_list_by_name().
556 * @dev: Device which requested the GPIOs
557 * @desc: List of GPIOs to free
558 * @count: Number of GPIOs in the list
559 * @return 0 if OK, -ve on error
561 int gpio_free_list(struct udevice *dev, struct gpio_desc *desc, int count);
564 * gpio_free_list_nodev() - free GPIOs without a device
566 * This is a version of gpio_free_list() that does not use a
567 * device. Avoid it unless the caller is not yet using driver model
569 int gpio_free_list_nodev(struct gpio_desc *desc, int count);
572 * dm_gpio_get_value() - Get the value of a GPIO
574 * This is the driver model version of the existing gpio_get_value() function
575 * and should be used instead of that.
577 * For now, these functions have a dm_ prefix since they conflict with
580 * @desc: GPIO description containing device, offset and flags,
581 * previously returned by gpio_request_by_name()
582 * @return GPIO value (0 for inactive, 1 for active) or -ve on error
584 int dm_gpio_get_value(const struct gpio_desc *desc);
586 int dm_gpio_set_value(const struct gpio_desc *desc, int value);
589 * dm_gpio_get_open_drain() - Check if open-drain-mode of a GPIO is active
591 * This checks if open-drain-mode for a GPIO is enabled or not. This method is
594 * @desc: GPIO description containing device, offset and flags,
595 * previously returned by gpio_request_by_name()
596 * @return Value of open drain mode for GPIO (0 for inactive, 1 for active) or
599 int dm_gpio_get_open_drain(struct gpio_desc *desc);
602 * dm_gpio_set_open_drain() - Switch open-drain-mode of a GPIO on or off
604 * This enables or disables open-drain mode for a GPIO. This method is
605 * optional; if the driver does not support it, nothing happens when the method
608 * In open-drain mode, instead of actively driving the output (Push-pull
609 * output), the GPIO's pin is connected to the collector (for a NPN transistor)
610 * or the drain (for a MOSFET) of a transistor, respectively. The pin then
611 * either forms an open circuit or a connection to ground, depending on the
612 * state of the transistor.
614 * @desc: GPIO description containing device, offset and flags,
615 * previously returned by gpio_request_by_name()
616 * @return 0 if OK, -ve on error
618 int dm_gpio_set_open_drain(struct gpio_desc *desc, int value);
621 * dm_gpio_set_dir() - Set the direction for a GPIO
623 * This sets up the direction according tot the provided flags. It will do
624 * nothing unless the direction is actually specified.
626 * @desc: GPIO description containing device, offset and flags,
627 * previously returned by gpio_request_by_name()
628 * @return 0 if OK, -ve on error
630 int dm_gpio_set_dir(struct gpio_desc *desc);
633 * dm_gpio_set_dir_flags() - Set direction using specific flags
635 * This is like dm_gpio_set_dir() except that the flags value is provided
636 * instead of being used from desc->flags. This is needed because in many
637 * cases the GPIO description does not include direction information.
638 * Note that desc->flags is updated by this function.
640 * @desc: GPIO description containing device, offset and flags,
641 * previously returned by gpio_request_by_name()
642 * @flags: New flags to use
643 * @return 0 if OK, -ve on error, in which case desc->flags is not updated
645 int dm_gpio_set_dir_flags(struct gpio_desc *desc, ulong flags);
648 * gpio_get_number() - Get the global GPIO number of a GPIO
650 * This should only be used for debugging or interest. It returns the number
651 * that should be used for gpio_get_value() etc. to access this GPIO.
653 * @desc: GPIO description containing device, offset and flags,
654 * previously returned by gpio_request_by_name()
655 * @return GPIO number, or -ve if not found
657 int gpio_get_number(const struct gpio_desc *desc);
659 #endif /* _ASM_GENERIC_GPIO_H_ */