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 gp 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 * Request a GPIO and configure it
66 * @param gpios pointer to array of gpio defs
67 * @param count number of GPIOs to set up
69 int gpio_request_one(unsigned gpio, enum gpio_flags flags, const char *label);
72 * Request a set of GPIOs and configure them
73 * @param gpios pointer to array of gpio defs
74 * @param count number of GPIOs to set up
76 int gpio_request_array(const struct gpio *gpios, int count);
79 * @deprecated Please use driver model instead
80 * Stop using the GPIO. This function should not alter pin configuration.
82 * @param gpio GPIO number
83 * @return 0 if ok, -1 on error
85 int gpio_free(unsigned gpio);
88 * @deprecated Please use driver model instead
89 * Release a set of GPIOs
90 * @param gpios pointer to array of gpio defs
91 * @param count number of GPIOs to set up
93 int gpio_free_array(const struct gpio *gpios, int count);
96 * @deprecated Please use driver model instead
97 * Make a GPIO an input.
99 * @param gpio GPIO number
100 * @return 0 if ok, -1 on error
102 int gpio_direction_input(unsigned gpio);
105 * @deprecated Please use driver model instead
106 * Make a GPIO an output, and set its value.
108 * @param gpio GPIO number
109 * @param value GPIO value (0 for low or 1 for high)
110 * @return 0 if ok, -1 on error
112 int gpio_direction_output(unsigned gpio, int value);
115 * @deprecated Please use driver model instead
116 * Get a GPIO's value. This will work whether the GPIO is an input
119 * @param gpio GPIO number
120 * @return 0 if low, 1 if high, -1 on error
122 int gpio_get_value(unsigned gpio);
125 * @deprecated Please use driver model instead
126 * Set an output GPIO's value. The GPIO must already be an output or
127 * this function may have no effect.
129 * @param gpio GPIO number
130 * @param value GPIO value (0 for low or 1 for high)
131 * @return 0 if ok, -1 on error
133 int gpio_set_value(unsigned gpio, int value);
135 /* State of a GPIO, as reported by get_function() */
139 GPIOF_UNUSED, /* Not claimed */
140 GPIOF_UNKNOWN, /* Not known */
141 GPIOF_FUNC, /* Not used as a GPIO */
149 struct udevice *dev; /* Device, NULL for invalid GPIO */
151 #define GPIOD_REQUESTED (1 << 0) /* Requested/claimed */
152 #define GPIOD_IS_OUT (1 << 1) /* GPIO is an output */
153 #define GPIOD_IS_IN (1 << 2) /* GPIO is an output */
154 #define GPIOD_ACTIVE_LOW (1 << 3) /* value has active low */
155 #define GPIOD_IS_OUT_ACTIVE (1 << 4) /* set output active */
157 uint offset; /* GPIO offset within the device */
159 * We could consider adding the GPIO label in here. Possibly we could
160 * use this structure for internal GPIO information.
165 * dm_gpio_is_valid() - Check if a GPIO is gpio_is_valie
167 * @desc: GPIO description containing device, offset and flags,
168 * previously returned by gpio_request_by_name()
169 * @return true if valid, false if not
171 static inline bool dm_gpio_is_valid(struct gpio_desc *desc)
173 return desc->dev != NULL;
177 * gpio_get_status() - get the current GPIO status as a string
179 * Obtain the current GPIO status as a string which can be presented to the
180 * user. A typical string is:
182 * "b4: in: 1 [x] sdmmc_cd"
184 * which means this is GPIO bank b, offset 4, currently set to input, current
185 * value 1, [x] means that it is requested and the owner is 'sdmmc_cd'
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 * @buf: Place to put string
192 * @buffsize: Size of string including \0
194 int gpio_get_status(struct udevice *dev, int offset, char *buf, int buffsize);
197 * gpio_get_function() - get the current function for a GPIO pin
199 * Note this returns GPIOF_UNUSED if the GPIO is not requested.
201 * TODO(sjg@chromium.org): This should use struct gpio_desc
203 * @dev: Device to check
204 * @offset: Offset of device GPIO to check
205 * @namep: If non-NULL, this is set to the nane given when the GPIO
206 * was requested, or -1 if it has not been requested
207 * @return -ENODATA if the driver returned an unknown function,
208 * -ENODEV if the device is not active, -EINVAL if the offset is invalid.
209 * GPIOF_UNUSED if the GPIO has not been requested. Otherwise returns the
210 * function from enum gpio_func_t.
212 int gpio_get_function(struct udevice *dev, int offset, const char **namep);
215 * gpio_get_raw_function() - get the current raw function for a GPIO pin
217 * Note this does not return GPIOF_UNUSED - it will always return the GPIO
218 * driver's view of a pin function, even if it is not correctly set up.
220 * TODO(sjg@chromium.org): This should use struct gpio_desc
222 * @dev: Device to check
223 * @offset: Offset of device GPIO to check
224 * @namep: If non-NULL, this is set to the nane given when the GPIO
225 * was requested, or -1 if it has not been requested
226 * @return -ENODATA if the driver returned an unknown function,
227 * -ENODEV if the device is not active, -EINVAL if the offset is invalid.
228 * Otherwise returns the function from enum gpio_func_t.
230 int gpio_get_raw_function(struct udevice *dev, int offset, const char **namep);
233 * gpio_requestf() - request a GPIO using a format string for the owner
235 * This is a helper function for gpio_request(). It allows you to provide
236 * a printf()-format string for the GPIO owner. It calls gpio_request() with
237 * the string that is created
239 int gpio_requestf(unsigned gpio, const char *fmt, ...)
240 __attribute__ ((format (__printf__, 2, 3)));
242 struct fdtdec_phandle_args;
245 * struct struct dm_gpio_ops - Driver model GPIO operations
247 * Refer to functions above for description. These function largely copy
250 * This is trying to be close to Linux GPIO API. Once the U-Boot uses the
251 * new DM GPIO API, this should be really easy to flip over to the Linux
252 * GPIO API-alike interface.
254 * Also it would be useful to standardise additional functions like
255 * pullup, slew rate and drive strength.
257 * gpio_request)( and gpio_free() are optional - if NULL then they will
260 * Note that @offset is the offset from the base GPIO of the device. So
261 * offset 0 is the device's first GPIO and offset o-1 is the last GPIO,
262 * where o is the number of GPIO lines controlled by the device. A device
263 * is typically used to control a single bank of GPIOs. Within complex
264 * SoCs there may be many banks and therefore many devices all referring
265 * to the different IO addresses within the SoC.
267 * The uclass combines all GPIO devices together to provide a consistent
268 * numbering from 0 to n-1, where n is the number of GPIOs in total across
269 * all devices. Be careful not to confuse offset with gpio in the parameters.
272 int (*request)(struct udevice *dev, unsigned offset, const char *label);
273 int (*free)(struct udevice *dev, unsigned offset);
274 int (*direction_input)(struct udevice *dev, unsigned offset);
275 int (*direction_output)(struct udevice *dev, unsigned offset,
277 int (*get_value)(struct udevice *dev, unsigned offset);
278 int (*set_value)(struct udevice *dev, unsigned offset, int value);
280 * get_function() Get the GPIO function
282 * @dev: Device to check
283 * @offset: GPIO offset within that device
284 * @return current function - GPIOF_...
286 int (*get_function)(struct udevice *dev, unsigned offset);
289 * xlate() - Translate phandle arguments into a GPIO description
291 * This function should set up the fields in desc according to the
292 * information in the arguments. The uclass will have set up:
296 * @desc->offset to the value of the first argument in args, if any,
297 * otherwise -1 (which is invalid)
299 * This method is optional so if the above defaults suit it can be
300 * omitted. Typical behaviour is to set up the GPIOD_ACTIVE_LOW flag
303 * Note that @dev is passed in as a parameter to follow driver model
304 * uclass conventions, even though it is already available as
308 * @desc: Place to put GPIO description
309 * @args: Arguments provided in descripion
310 * @return 0 if OK, -ve on error
312 int (*xlate)(struct udevice *dev, struct gpio_desc *desc,
313 struct fdtdec_phandle_args *args);
317 * struct gpio_dev_priv - information about a device used by the uclass
319 * The uclass combines all active GPIO devices into a unified numbering
320 * scheme. To do this it maintains some private information about each
323 * To implement driver model support in your GPIO driver, add a probe
324 * handler, and set @gpio_count and @bank_name correctly in that handler.
325 * This tells the uclass the name of the GPIO bank and the number of GPIOs
328 * @bank_name: Name of the GPIO device (e.g 'a' means GPIOs will be called
330 * @gpio_count: Number of GPIOs in this device
331 * @gpio_base: Base GPIO number for this device. For the first active device
332 * this will be 0; the numbering for others will follow sequentially so that
333 * @gpio_base for device 1 will equal the number of GPIOs in device 0.
334 * @name: Array of pointers to the name for each GPIO in this bank. The
335 * value of the pointer will be NULL if the GPIO has not been claimed.
337 struct gpio_dev_priv {
338 const char *bank_name;
344 /* Access the GPIO operations for a device */
345 #define gpio_get_ops(dev) ((struct dm_gpio_ops *)(dev)->driver->ops)
348 * gpio_get_bank_info - Return information about a GPIO bank/device
350 * This looks up a device and returns both its GPIO base name and the number
351 * of GPIOs it controls.
353 * @dev: Device to look up
354 * @offset_count: Returns number of GPIOs within this bank
355 * @return bank name of this device
357 const char *gpio_get_bank_info(struct udevice *dev, int *offset_count);
360 * gpio_lookup_name - Look up a GPIO name and return its details
362 * This is used to convert a named GPIO into a device, offset and GPIO
365 * @name: GPIO name to look up
366 * @devp: Returns pointer to device which contains this GPIO
367 * @offsetp: Returns the offset number within this device
368 * @gpiop: Returns the absolute GPIO number, numbered from 0
370 int gpio_lookup_name(const char *name, struct udevice **devp,
371 unsigned int *offsetp, unsigned int *gpiop);
374 * get_gpios() - Turn the values of a list of GPIOs into an integer
376 * This puts the value of the first GPIO into bit 0, the second into bit 1,
377 * etc. then returns the resulting integer.
379 * @gpio_list: List of GPIOs to collect
380 * @return resulting integer value
382 unsigned gpio_get_values_as_int(const int *gpio_list);
385 * gpio_request_by_name() - Locate and request a GPIO by name
387 * This operates by looking up the given list name in the device (device
388 * tree property) and requesting the GPIO for use. The property must exist
391 * Use @flags to specify whether the GPIO should be an input or output. In
392 * principle this can also come from the device tree binding but most
393 * bindings don't provide this information. Specifically, when the GPIO uclass
394 * calls the xlate() method, it can return default flags, which are then
395 * ORed with this @flags.
397 * If we find that requesting the GPIO is not always needed we could add a
398 * new function or a new GPIOD_NO_REQUEST flag.
400 * At present driver model has no reference counting so if one device
401 * requests a GPIO which subsequently is unbound, the @desc->dev pointer
402 * will be invalid. However this will only happen if the GPIO device is
403 * unbound, not if it is removed, so this seems like a reasonable limitation
404 * for now. There is no real use case for unbinding drivers in normal
407 * The device tree binding is doc/device-tree-bindings/gpio/gpio.txt in
408 * generate terms and each specific device may add additional details in
409 * a binding file in the same directory.
411 * @dev: Device requesting the GPIO
412 * @list_name: Name of GPIO list (e.g. "board-id-gpios")
413 * @index: Index number of the GPIO in that list use request (0=first)
414 * @desc: Returns GPIO description information. If there is no such
415 * GPIO, dev->dev will be NULL.
416 * @flags: Indicates the GPIO input/output settings (GPIOD_...)
417 * @return 0 if OK, -ENOENT if the GPIO does not exist, -EINVAL if there is
418 * something wrong with the list, or other -ve for another error (e.g.
419 * -EBUSY if a GPIO was already requested)
421 int gpio_request_by_name(struct udevice *dev, const char *list_name,
422 int index, struct gpio_desc *desc, int flags);
425 * gpio_request_list_by_name() - Request a list of GPIOs
427 * Reads all the GPIOs from a list and requetss them. See
428 * gpio_request_by_name() for additional details. Lists should not be
429 * misused to hold unrelated or optional GPIOs. They should only be used
430 * for things like parallel data lines. A zero phandle terminates the list
433 * This function will either succeed, and request all GPIOs in the list, or
434 * fail and request none (it will free already-requested GPIOs in case of
435 * an error part-way through).
437 * @dev: Device requesting the GPIO
438 * @list_name: Name of GPIO list (e.g. "board-id-gpios")
439 * @desc_list: Returns a list of GPIO description information
440 * @max_count: Maximum number of GPIOs to return (@desc_list must be at least
442 * @flags: Indicates the GPIO input/output settings (GPIOD_...)
443 * @return number of GPIOs requested, or -ve on error
445 int gpio_request_list_by_name(struct udevice *dev, const char *list_name,
446 struct gpio_desc *desc_list, int max_count,
450 * gpio_get_list_count() - Returns the number of GPIOs in a list
452 * Counts the GPIOs in a list. See gpio_request_by_name() for additional
455 * @dev: Device requesting the GPIO
456 * @list_name: Name of GPIO list (e.g. "board-id-gpios")
457 * @return number of GPIOs (0 for an empty property) or -ENOENT if the list
460 int gpio_get_list_count(struct udevice *dev, const char *list_name);
463 * gpio_request_by_name_nodev() - request GPIOs without a device
465 * This is a version of gpio_request_list_by_name() that does not use a
466 * device. Avoid it unless the caller is not yet using driver model
468 int gpio_request_by_name_nodev(const void *blob, int node,
469 const char *list_name,
470 int index, struct gpio_desc *desc, int flags);
473 * gpio_request_list_by_name_nodev() - request GPIOs without a device
475 * This is a version of gpio_request_list_by_name() that does not use a
476 * device. Avoid it unless the caller is not yet using driver model
478 int gpio_request_list_by_name_nodev(const void *blob, int node,
479 const char *list_name,
480 struct gpio_desc *desc_list, int max_count,
484 * dm_gpio_free() - Free a single GPIO
486 * This frees a single GPIOs previously returned from gpio_request_by_name().
488 * @dev: Device which requested the GPIO
489 * @desc: GPIO to free
490 * @return 0 if OK, -ve on error
492 int dm_gpio_free(struct udevice *dev, struct gpio_desc *desc);
495 * gpio_free_list() - Free a list of GPIOs
497 * This frees a list of GPIOs previously returned from
498 * gpio_request_list_by_name().
500 * @dev: Device which requested the GPIOs
501 * @desc: List of GPIOs to free
502 * @count: Number of GPIOs in the list
503 * @return 0 if OK, -ve on error
505 int gpio_free_list(struct udevice *dev, struct gpio_desc *desc, int count);
508 * gpio_free_list_nodev() - free GPIOs without a device
510 * This is a version of gpio_free_list() that does not use a
511 * device. Avoid it unless the caller is not yet using driver model
513 int gpio_free_list_nodev(struct gpio_desc *desc, int count);
516 * dm_gpio_get_value() - Get the value of a GPIO
518 * This is the driver model version of the existing gpio_get_value() function
519 * and should be used instead of that.
521 * For now, these functions have a dm_ prefix since they conflict with
524 * @desc: GPIO description containing device, offset and flags,
525 * previously returned by gpio_request_by_name()
526 * @return GPIO value (0 for inactive, 1 for active) or -ve on error
528 int dm_gpio_get_value(struct gpio_desc *desc);
530 int dm_gpio_set_value(struct gpio_desc *desc, int value);
533 * dm_gpio_set_dir() - Set the direction for a GPIO
535 * This sets up the direction according tot the provided flags. It will do
536 * nothing unless the direction is actually specified.
538 * @desc: GPIO description containing device, offset and flags,
539 * previously returned by gpio_request_by_name()
540 * @return 0 if OK, -ve on error
542 int dm_gpio_set_dir(struct gpio_desc *desc);
545 * dm_gpio_set_dir_flags() - Set direction using specific flags
547 * This is like dm_gpio_set_dir() except that the flags value is provided
548 * instead of being used from desc->flags. This is needed because in many
549 * cases the GPIO description does not include direction information.
550 * Note that desc->flags is updated by this function.
552 * @desc: GPIO description containing device, offset and flags,
553 * previously returned by gpio_request_by_name()
554 * @flags: New flags to use
555 * @return 0 if OK, -ve on error, in which case desc->flags is not updated
557 int dm_gpio_set_dir_flags(struct gpio_desc *desc, ulong flags);
560 * gpio_get_number() - Get the global GPIO number of a GPIO
562 * This should only be used for debugging or interest. It returns the nummber
563 * that should be used for gpio_get_value() etc. to access this GPIO.
565 * @desc: GPIO description containing device, offset and flags,
566 * previously returned by gpio_request_by_name()
567 * @return GPIO number, or -ve if not found
569 int gpio_get_number(struct gpio_desc *desc);
571 #endif /* _ASM_GENERIC_GPIO_H_ */