xref: /openbmc/u-boot/include/asm-generic/gpio.h (revision 6df98cfc)
1 /* SPDX-License-Identifier: GPL-2.0+ */
2 /*
3  * Copyright (c) 2011 The Chromium OS Authors.
4  * Copyright (c) 2011, NVIDIA Corp. All rights reserved.
5  */
6 
7 #ifndef _ASM_GENERIC_GPIO_H_
8 #define _ASM_GENERIC_GPIO_H_
9 
10 #include <dm/ofnode.h>
11 
12 struct ofnode_phandle_args;
13 
14 /*
15  * Generic GPIO API for U-Boot
16  *
17  * --
18  * NB: This is deprecated. Please use the driver model functions instead:
19  *
20  *    - gpio_request_by_name()
21  *    - dm_gpio_get_value() etc.
22  *
23  * For now we need a dm_ prefix on some functions to avoid name collision.
24  * --
25  *
26  * GPIOs are numbered from 0 to GPIO_COUNT-1 which value is defined
27  * by the SOC/architecture.
28  *
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.
34  *
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.
39  */
40 
41 /**
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.
45  *
46  * Note: With driver model, the label is allocated so there is no need for
47  * the caller to preserve it.
48  *
49  * @param gpio	GPIO number
50  * @param label	User label for this GPIO
51  * @return 0 if ok, -1 on error
52  */
53 int gpio_request(unsigned gpio, const char *label);
54 
55 /**
56  * @deprecated	Please use driver model instead
57  * Stop using the GPIO.  This function should not alter pin configuration.
58  *
59  * @param gpio	GPIO number
60  * @return 0 if ok, -1 on error
61  */
62 int gpio_free(unsigned gpio);
63 
64 /**
65  * @deprecated	Please use driver model instead
66  * Make a GPIO an input.
67  *
68  * @param gpio	GPIO number
69  * @return 0 if ok, -1 on error
70  */
71 int gpio_direction_input(unsigned gpio);
72 
73 /**
74  * @deprecated	Please use driver model instead
75  * Make a GPIO an output, and set its value.
76  *
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
80  */
81 int gpio_direction_output(unsigned gpio, int value);
82 
83 /**
84  * @deprecated	Please use driver model instead
85  * Get a GPIO's value. This will work whether the GPIO is an input
86  * or an output.
87  *
88  * @param gpio	GPIO number
89  * @return 0 if low, 1 if high, -1 on error
90  */
91 int gpio_get_value(unsigned gpio);
92 
93 /**
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.
97  *
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
101  */
102 int gpio_set_value(unsigned gpio, int value);
103 
104 /* State of a GPIO, as reported by get_function() */
105 enum gpio_func_t {
106 	GPIOF_INPUT = 0,
107 	GPIOF_OUTPUT,
108 	GPIOF_UNUSED,		/* Not claimed */
109 	GPIOF_UNKNOWN,		/* Not known */
110 	GPIOF_FUNC,		/* Not used as a GPIO */
111 
112 	GPIOF_COUNT,
113 };
114 
115 struct udevice;
116 
117 struct gpio_desc {
118 	struct udevice *dev;	/* Device, NULL for invalid GPIO */
119 	unsigned long flags;
120 #define GPIOD_REQUESTED		(1 << 0)	/* Requested/claimed */
121 #define GPIOD_IS_OUT		(1 << 1)	/* GPIO is an output */
122 #define GPIOD_IS_IN		(1 << 2)	/* GPIO is an input */
123 #define GPIOD_ACTIVE_LOW	(1 << 3)	/* value has active low */
124 #define GPIOD_IS_OUT_ACTIVE	(1 << 4)	/* set output active */
125 
126 	uint offset;		/* GPIO offset within the device */
127 	/*
128 	 * We could consider adding the GPIO label in here. Possibly we could
129 	 * use this structure for internal GPIO information.
130 	 */
131 };
132 
133 /**
134  * dm_gpio_is_valid() - Check if a GPIO is valid
135  *
136  * @desc:	GPIO description containing device, offset and flags,
137  *		previously returned by gpio_request_by_name()
138  * @return true if valid, false if not
139  */
dm_gpio_is_valid(const struct gpio_desc * desc)140 static inline bool dm_gpio_is_valid(const struct gpio_desc *desc)
141 {
142 	return desc->dev != NULL;
143 }
144 
145 /**
146  * gpio_get_status() - get the current GPIO status as a string
147  *
148  * Obtain the current GPIO status as a string which can be presented to the
149  * user. A typical string is:
150  *
151  * "b4:  in: 1 [x] sdmmc_cd"
152  *
153  * which means this is GPIO bank b, offset 4, currently set to input, current
154  * value 1, [x] means that it is requested and the owner is 'sdmmc_cd'
155  *
156  * TODO(sjg@chromium.org): This should use struct gpio_desc
157  *
158  * @dev:	Device to check
159  * @offset:	Offset of device GPIO to check
160  * @buf:	Place to put string
161  * @buffsize:	Size of string including \0
162  */
163 int gpio_get_status(struct udevice *dev, int offset, char *buf, int buffsize);
164 
165 /**
166  * gpio_get_function() - get the current function for a GPIO pin
167  *
168  * Note this returns GPIOF_UNUSED if the GPIO is not requested.
169  *
170  * TODO(sjg@chromium.org): This should use struct gpio_desc
171  *
172  * @dev:	Device to check
173  * @offset:	Offset of device GPIO to check
174  * @namep:	If non-NULL, this is set to the name given when the GPIO
175  *		was requested, or -1 if it has not been requested
176  * @return  -ENODATA if the driver returned an unknown function,
177  * -ENODEV if the device is not active, -EINVAL if the offset is invalid.
178  * GPIOF_UNUSED if the GPIO has not been requested. Otherwise returns the
179  * function from enum gpio_func_t.
180  */
181 int gpio_get_function(struct udevice *dev, int offset, const char **namep);
182 
183 /**
184  * gpio_get_raw_function() - get the current raw function for a GPIO pin
185  *
186  * Note this does not return GPIOF_UNUSED - it will always return the GPIO
187  * driver's view of a pin function, even if it is not correctly set up.
188  *
189  * TODO(sjg@chromium.org): This should use struct gpio_desc
190  *
191  * @dev:	Device to check
192  * @offset:	Offset of device GPIO to check
193  * @namep:	If non-NULL, this is set to the name given when the GPIO
194  *		was requested, or -1 if it has not been requested
195  * @return  -ENODATA if the driver returned an unknown function,
196  * -ENODEV if the device is not active, -EINVAL if the offset is invalid.
197  * Otherwise returns the function from enum gpio_func_t.
198  */
199 int gpio_get_raw_function(struct udevice *dev, int offset, const char **namep);
200 
201 /**
202  * gpio_requestf() - request a GPIO using a format string for the owner
203  *
204  * This is a helper function for gpio_request(). It allows you to provide
205  * a printf()-format string for the GPIO owner. It calls gpio_request() with
206  * the string that is created
207  */
208 int gpio_requestf(unsigned gpio, const char *fmt, ...)
209 		__attribute__ ((format (__printf__, 2, 3)));
210 
211 struct fdtdec_phandle_args;
212 
213 /**
214  * gpio_xlate_offs_flags() - implementation for common use of dm_gpio_ops.xlate
215  *
216  * This routine sets the offset field to args[0] and the flags field to
217  * GPIOD_ACTIVE_LOW if the GPIO_ACTIVE_LOW flag is present in args[1].
218  */
219 int gpio_xlate_offs_flags(struct udevice *dev, struct gpio_desc *desc,
220 			  struct ofnode_phandle_args *args);
221 
222 /**
223  * struct struct dm_gpio_ops - Driver model GPIO operations
224  *
225  * Refer to functions above for description. These function largely copy
226  * the old API.
227  *
228  * This is trying to be close to Linux GPIO API. Once the U-Boot uses the
229  * new DM GPIO API, this should be really easy to flip over to the Linux
230  * GPIO API-alike interface.
231  *
232  * Also it would be useful to standardise additional functions like
233  * pullup, slew rate and drive strength.
234  *
235  * gpio_request() and gpio_free() are optional - if NULL then they will
236  * not be called.
237  *
238  * Note that @offset is the offset from the base GPIO of the device. So
239  * offset 0 is the device's first GPIO and offset o-1 is the last GPIO,
240  * where o is the number of GPIO lines controlled by the device. A device
241  * is typically used to control a single bank of GPIOs. Within complex
242  * SoCs there may be many banks and therefore many devices all referring
243  * to the different IO addresses within the SoC.
244  *
245  * The uclass combines all GPIO devices together to provide a consistent
246  * numbering from 0 to n-1, where n is the number of GPIOs in total across
247  * all devices. Be careful not to confuse offset with gpio in the parameters.
248  */
249 struct dm_gpio_ops {
250 	int (*request)(struct udevice *dev, unsigned offset, const char *label);
251 	int (*free)(struct udevice *dev, unsigned offset);
252 	int (*direction_input)(struct udevice *dev, unsigned offset);
253 	int (*direction_output)(struct udevice *dev, unsigned offset,
254 				int value);
255 	int (*get_value)(struct udevice *dev, unsigned offset);
256 	int (*set_value)(struct udevice *dev, unsigned offset, int value);
257 	int (*get_open_drain)(struct udevice *dev, unsigned offset);
258 	int (*set_open_drain)(struct udevice *dev, unsigned offset, int value);
259 	/**
260 	 * get_function() Get the GPIO function
261 	 *
262 	 * @dev:     Device to check
263 	 * @offset:  GPIO offset within that device
264 	 * @return current function - GPIOF_...
265 	 */
266 	int (*get_function)(struct udevice *dev, unsigned offset);
267 
268 	/**
269 	 * xlate() - Translate phandle arguments into a GPIO description
270 	 *
271 	 * This function should set up the fields in desc according to the
272 	 * information in the arguments. The uclass will have set up:
273 	 *
274 	 *   @desc->dev to @dev
275 	 *   @desc->flags to 0
276 	 *   @desc->offset to 0
277 	 *
278 	 * This method is optional and defaults to gpio_xlate_offs_flags,
279 	 * which will parse offset and the GPIO_ACTIVE_LOW flag in the first
280 	 * two arguments.
281 	 *
282 	 * Note that @dev is passed in as a parameter to follow driver model
283 	 * uclass conventions, even though it is already available as
284 	 * desc->dev.
285 	 *
286 	 * @dev:	GPIO device
287 	 * @desc:	Place to put GPIO description
288 	 * @args:	Arguments provided in description
289 	 * @return 0 if OK, -ve on error
290 	 */
291 	int (*xlate)(struct udevice *dev, struct gpio_desc *desc,
292 		     struct ofnode_phandle_args *args);
293 };
294 
295 /**
296  * struct gpio_dev_priv - information about a device used by the uclass
297  *
298  * The uclass combines all active GPIO devices into a unified numbering
299  * scheme. To do this it maintains some private information about each
300  * device.
301  *
302  * To implement driver model support in your GPIO driver, add a probe
303  * handler, and set @gpio_count and @bank_name correctly in that handler.
304  * This tells the uclass the name of the GPIO bank and the number of GPIOs
305  * it contains.
306  *
307  * @bank_name: Name of the GPIO device (e.g 'a' means GPIOs will be called
308  * 'A0', 'A1', etc.
309  * @gpio_count: Number of GPIOs in this device
310  * @gpio_base: Base GPIO number for this device. For the first active device
311  * this will be 0; the numbering for others will follow sequentially so that
312  * @gpio_base for device 1 will equal the number of GPIOs in device 0.
313  * @name: Array of pointers to the name for each GPIO in this bank. The
314  * value of the pointer will be NULL if the GPIO has not been claimed.
315  */
316 struct gpio_dev_priv {
317 	const char *bank_name;
318 	unsigned gpio_count;
319 	unsigned gpio_base;
320 	char **name;
321 };
322 
323 /* Access the GPIO operations for a device */
324 #define gpio_get_ops(dev)	((struct dm_gpio_ops *)(dev)->driver->ops)
325 
326 /**
327  * gpio_get_bank_info - Return information about a GPIO bank/device
328  *
329  * This looks up a device and returns both its GPIO base name and the number
330  * of GPIOs it controls.
331  *
332  * @dev: Device to look up
333  * @offset_count: Returns number of GPIOs within this bank
334  * @return bank name of this device
335  */
336 const char *gpio_get_bank_info(struct udevice *dev, int *offset_count);
337 
338 /**
339  * dm_gpio_lookup_name() - Look up a named GPIO and return its description
340  *
341  * The name of a GPIO is typically its bank name followed by a number from 0.
342  * For example A0 is the first GPIO in bank A. Each bank is a separate driver
343  * model device.
344  *
345  * @name:	Name to look up
346  * @desc:	Returns description, on success
347  * @return 0 if OK, -ve on error
348  */
349 int dm_gpio_lookup_name(const char *name, struct gpio_desc *desc);
350 
351 /**
352  * gpio_hog_lookup_name() - Look up a named GPIO and return the gpio descr.
353  *
354  * @name:	Name to look up
355  * @desc:	Returns GPIO description, on success, else NULL
356  * @return:	Returns 0 if OK, else -ENODEV
357  */
358 int gpio_hog_lookup_name(const char *name, struct gpio_desc **desc);
359 
360 /**
361  * gpio_hog_probe_all() - probe all gpio devices with
362  * gpio-hog subnodes.
363  *
364  * @return:	Returns return value from device_probe()
365  */
366 int gpio_hog_probe_all(void);
367 
368 /**
369  * gpio_lookup_name - Look up a GPIO name and return its details
370  *
371  * This is used to convert a named GPIO into a device, offset and GPIO
372  * number.
373  *
374  * @name: GPIO name to look up
375  * @devp: Returns pointer to device which contains this GPIO
376  * @offsetp: Returns the offset number within this device
377  * @gpiop: Returns the absolute GPIO number, numbered from 0
378  */
379 int gpio_lookup_name(const char *name, struct udevice **devp,
380 		     unsigned int *offsetp, unsigned int *gpiop);
381 
382 /**
383  * gpio_get_values_as_int() - Turn the values of a list of GPIOs into an int
384  *
385  * This puts the value of the first GPIO into bit 0, the second into bit 1,
386  * etc. then returns the resulting integer.
387  *
388  * @gpio_list: List of GPIOs to collect
389  * @return resulting integer value, or -ve on error
390  */
391 int gpio_get_values_as_int(const int *gpio_list);
392 
393 /**
394  * dm_gpio_get_values_as_int() - Turn the values of a list of GPIOs into an int
395  *
396  * This puts the value of the first GPIO into bit 0, the second into bit 1,
397  * etc. then returns the resulting integer.
398  *
399  * @desc_list: List of GPIOs to collect
400  * @count: Number of GPIOs
401  * @return resulting integer value, or -ve on error
402  */
403 int dm_gpio_get_values_as_int(const struct gpio_desc *desc_list, int count);
404 
405 /**
406  * gpio_claim_vector() - claim a number of GPIOs for input
407  *
408  * @gpio_num_array:	array of gpios to claim, terminated by -1
409  * @fmt:		format string for GPIO names, e.g. "board_id%d"
410  * @return 0 if OK, -ve on error
411  */
412 int gpio_claim_vector(const int *gpio_num_array, const char *fmt);
413 
414 /**
415  * gpio_request_by_name() - Locate and request a GPIO by name
416  *
417  * This operates by looking up the given list name in the device (device
418  * tree property) and requesting the GPIO for use. The property must exist
419  * in @dev's node.
420  *
421  * Use @flags to specify whether the GPIO should be an input or output. In
422  * principle this can also come from the device tree binding but most
423  * bindings don't provide this information. Specifically, when the GPIO uclass
424  * calls the xlate() method, it can return default flags, which are then
425  * ORed with this @flags.
426  *
427  * If we find that requesting the GPIO is not always needed we could add a
428  * new function or a new GPIOD_NO_REQUEST flag.
429  *
430  * At present driver model has no reference counting so if one device
431  * requests a GPIO which subsequently is unbound, the @desc->dev pointer
432  * will be invalid. However this will only happen if the GPIO device is
433  * unbound, not if it is removed, so this seems like a reasonable limitation
434  * for now. There is no real use case for unbinding drivers in normal
435  * operation.
436  *
437  * The device tree binding is doc/device-tree-bindings/gpio/gpio.txt in
438  * generate terms and each specific device may add additional details in
439  * a binding file in the same directory.
440  *
441  * @dev:	Device requesting the GPIO
442  * @list_name:	Name of GPIO list (e.g. "board-id-gpios")
443  * @index:	Index number of the GPIO in that list use request (0=first)
444  * @desc:	Returns GPIO description information. If there is no such
445  *		GPIO, dev->dev will be NULL.
446  * @flags:	Indicates the GPIO input/output settings (GPIOD_...)
447  * @return 0 if OK, -ENOENT if the GPIO does not exist, -EINVAL if there is
448  * something wrong with the list, or other -ve for another error (e.g.
449  * -EBUSY if a GPIO was already requested)
450  */
451 int gpio_request_by_name(struct udevice *dev, const char *list_name,
452 			 int index, struct gpio_desc *desc, int flags);
453 
454 /**
455  * gpio_request_list_by_name() - Request a list of GPIOs
456  *
457  * Reads all the GPIOs from a list and requests them. See
458  * gpio_request_by_name() for additional details. Lists should not be
459  * misused to hold unrelated or optional GPIOs. They should only be used
460  * for things like parallel data lines. A zero phandle terminates the list
461  * the list.
462  *
463  * This function will either succeed, and request all GPIOs in the list, or
464  * fail and request none (it will free already-requested GPIOs in case of
465  * an error part-way through).
466  *
467  * @dev:	Device requesting the GPIO
468  * @list_name:	Name of GPIO list (e.g. "board-id-gpios")
469  * @desc_list:	Returns a list of GPIO description information
470  * @max_count:	Maximum number of GPIOs to return (@desc_list must be at least
471  *		this big)
472  * @flags:	Indicates the GPIO input/output settings (GPIOD_...)
473  * @return number of GPIOs requested, or -ve on error
474  */
475 int gpio_request_list_by_name(struct udevice *dev, const char *list_name,
476 			      struct gpio_desc *desc_list, int max_count,
477 			      int flags);
478 
479 /**
480  * dm_gpio_request() - manually request a GPIO
481  *
482  * Note: This function should only be used for testing / debugging. Instead.
483  * use gpio_request_by_name() to pull GPIOs from the device tree.
484  *
485  * @desc:	GPIO description of GPIO to request (see dm_gpio_lookup_name())
486  * @label:	Label to attach to the GPIO while claimed
487  * @return 0 if OK, -ve on error
488  */
489 int dm_gpio_request(struct gpio_desc *desc, const char *label);
490 
491 /**
492  * gpio_get_list_count() - Returns the number of GPIOs in a list
493  *
494  * Counts the GPIOs in a list. See gpio_request_by_name() for additional
495  * details.
496  *
497  * @dev:	Device requesting the GPIO
498  * @list_name:	Name of GPIO list (e.g. "board-id-gpios")
499  * @return number of GPIOs (0 for an empty property) or -ENOENT if the list
500  * does not exist
501  */
502 int gpio_get_list_count(struct udevice *dev, const char *list_name);
503 
504 /**
505  * gpio_request_by_name_nodev() - request GPIOs without a device
506  *
507  * This is a version of gpio_request_list_by_name() that does not use a
508  * device. Avoid it unless the caller is not yet using driver model
509  */
510 int gpio_request_by_name_nodev(ofnode node, const char *list_name, int index,
511 			       struct gpio_desc *desc, int flags);
512 
513 /**
514  * gpio_request_list_by_name_nodev() - request GPIOs without a device
515  *
516  * This is a version of gpio_request_list_by_name() that does not use a
517  * device. Avoid it unless the caller is not yet using driver model
518  */
519 int gpio_request_list_by_name_nodev(ofnode node, const char *list_name,
520 				    struct gpio_desc *desc_list, int max_count,
521 				    int flags);
522 
523 /**
524  * gpio_dev_request_index() - request single GPIO from gpio device
525  *
526  * @dev:	GPIO device
527  * @nodename:	Name of node for which gpio gets requested, used
528  *		for the gpio label name
529  * @list_name:	Name of GPIO list (e.g. "board-id-gpios")
530  * @index:	Index number of the GPIO in that list use request (0=first)
531  * @flags:	GPIOD_* flags
532  * @dtflags:	GPIO flags read from DT defined see GPIOD_*
533  * @desc:	returns GPIO descriptor filled from this function
534  * @return:	return value from gpio_request_tail()
535  */
536 int gpio_dev_request_index(struct udevice *dev, const char *nodename,
537 			   char *list_name, int index, int flags,
538 			   int dtflags, struct gpio_desc *desc);
539 
540 /**
541  * dm_gpio_free() - Free a single GPIO
542  *
543  * This frees a single GPIOs previously returned from gpio_request_by_name().
544  *
545  * @dev:	Device which requested the GPIO
546  * @desc:	GPIO to free
547  * @return 0 if OK, -ve on error
548  */
549 int dm_gpio_free(struct udevice *dev, struct gpio_desc *desc);
550 
551 /**
552  * gpio_free_list() - Free a list of GPIOs
553  *
554  * This frees a list of GPIOs previously returned from
555  * gpio_request_list_by_name().
556  *
557  * @dev:	Device which requested the GPIOs
558  * @desc:	List of GPIOs to free
559  * @count:	Number of GPIOs in the list
560  * @return 0 if OK, -ve on error
561  */
562 int gpio_free_list(struct udevice *dev, struct gpio_desc *desc, int count);
563 
564 /**
565  * gpio_free_list_nodev() - free GPIOs without a device
566  *
567  * This is a version of gpio_free_list() that does not use a
568  * device. Avoid it unless the caller is not yet using driver model
569  */
570 int gpio_free_list_nodev(struct gpio_desc *desc, int count);
571 
572 /**
573  * dm_gpio_get_value() - Get the value of a GPIO
574  *
575  * This is the driver model version of the existing gpio_get_value() function
576  * and should be used instead of that.
577  *
578  * For now, these functions have a dm_ prefix since they conflict with
579  * existing names.
580  *
581  * @desc:	GPIO description containing device, offset and flags,
582  *		previously returned by gpio_request_by_name()
583  * @return GPIO value (0 for inactive, 1 for active) or -ve on error
584  */
585 int dm_gpio_get_value(const struct gpio_desc *desc);
586 
587 int dm_gpio_set_value(const struct gpio_desc *desc, int value);
588 
589 /**
590  * dm_gpio_get_open_drain() - Check if open-drain-mode of a GPIO is active
591  *
592  * This checks if open-drain-mode for a GPIO is enabled or not. This method is
593  * optional.
594  *
595  * @desc:	GPIO description containing device, offset and flags,
596  *		previously returned by gpio_request_by_name()
597  * @return Value of open drain mode for GPIO (0 for inactive, 1 for active) or
598  *	   -ve on error
599  */
600 int dm_gpio_get_open_drain(struct gpio_desc *desc);
601 
602 /**
603  * dm_gpio_set_open_drain() - Switch open-drain-mode of a GPIO on or off
604  *
605  * This enables or disables open-drain mode for a GPIO. This method is
606  * optional; if the driver does not support it, nothing happens when the method
607  * is called.
608  *
609  * In open-drain mode, instead of actively driving the output (Push-pull
610  * output), the GPIO's pin is connected to the collector (for a NPN transistor)
611  * or the drain (for a MOSFET) of a transistor, respectively. The pin then
612  * either forms an open circuit or a connection to ground, depending on the
613  * state of the transistor.
614  *
615  * @desc:	GPIO description containing device, offset and flags,
616  *		previously returned by gpio_request_by_name()
617  * @return 0 if OK, -ve on error
618  */
619 int dm_gpio_set_open_drain(struct gpio_desc *desc, int value);
620 
621 /**
622  * dm_gpio_set_dir() - Set the direction for a GPIO
623  *
624  * This sets up the direction according tot the provided flags. It will do
625  * nothing unless the direction is actually specified.
626  *
627  * @desc:	GPIO description containing device, offset and flags,
628  *		previously returned by gpio_request_by_name()
629  * @return 0 if OK, -ve on error
630  */
631 int dm_gpio_set_dir(struct gpio_desc *desc);
632 
633 /**
634  * dm_gpio_set_dir_flags() - Set direction using specific flags
635  *
636  * This is like dm_gpio_set_dir() except that the flags value is provided
637  * instead of being used from desc->flags. This is needed because in many
638  * cases the GPIO description does not include direction information.
639  * Note that desc->flags is updated by this function.
640  *
641  * @desc:	GPIO description containing device, offset and flags,
642  *		previously returned by gpio_request_by_name()
643  * @flags:	New flags to use
644  * @return 0 if OK, -ve on error, in which case desc->flags is not updated
645  */
646 int dm_gpio_set_dir_flags(struct gpio_desc *desc, ulong flags);
647 
648 /**
649  * gpio_get_number() - Get the global GPIO number of a GPIO
650  *
651  * This should only be used for debugging or interest. It returns the number
652  * that should be used for gpio_get_value() etc. to access this GPIO.
653  *
654  * @desc:	GPIO description containing device, offset and flags,
655  *		previously returned by gpio_request_by_name()
656  * @return GPIO number, or -ve if not found
657  */
658 int gpio_get_number(const struct gpio_desc *desc);
659 
660 #endif	/* _ASM_GENERIC_GPIO_H_ */
661