xref: /openbmc/linux/drivers/gpio/gpiolib-of.c (revision 4da722ca)
1 /*
2  * OF helpers for the GPIO API
3  *
4  * Copyright (c) 2007-2008  MontaVista Software, Inc.
5  *
6  * Author: Anton Vorontsov <avorontsov@ru.mvista.com>
7  *
8  * This program is free software; you can redistribute it and/or modify
9  * it under the terms of the GNU General Public License as published by
10  * the Free Software Foundation; either version 2 of the License, or
11  * (at your option) any later version.
12  */
13 
14 #include <linux/device.h>
15 #include <linux/err.h>
16 #include <linux/errno.h>
17 #include <linux/module.h>
18 #include <linux/io.h>
19 #include <linux/gpio/consumer.h>
20 #include <linux/of.h>
21 #include <linux/of_address.h>
22 #include <linux/of_gpio.h>
23 #include <linux/pinctrl/pinctrl.h>
24 #include <linux/slab.h>
25 #include <linux/gpio/machine.h>
26 
27 #include "gpiolib.h"
28 
29 static int of_gpiochip_match_node_and_xlate(struct gpio_chip *chip, void *data)
30 {
31 	struct of_phandle_args *gpiospec = data;
32 
33 	return chip->gpiodev->dev.of_node == gpiospec->np &&
34 				chip->of_xlate(chip, gpiospec, NULL) >= 0;
35 }
36 
37 static struct gpio_chip *of_find_gpiochip_by_xlate(
38 					struct of_phandle_args *gpiospec)
39 {
40 	return gpiochip_find(gpiospec, of_gpiochip_match_node_and_xlate);
41 }
42 
43 static struct gpio_desc *of_xlate_and_get_gpiod_flags(struct gpio_chip *chip,
44 					struct of_phandle_args *gpiospec,
45 					enum of_gpio_flags *flags)
46 {
47 	int ret;
48 
49 	if (chip->of_gpio_n_cells != gpiospec->args_count)
50 		return ERR_PTR(-EINVAL);
51 
52 	ret = chip->of_xlate(chip, gpiospec, flags);
53 	if (ret < 0)
54 		return ERR_PTR(ret);
55 
56 	return gpiochip_get_desc(chip, ret);
57 }
58 
59 /**
60  * of_get_named_gpiod_flags() - Get a GPIO descriptor and flags for GPIO API
61  * @np:		device node to get GPIO from
62  * @propname:	property name containing gpio specifier(s)
63  * @index:	index of the GPIO
64  * @flags:	a flags pointer to fill in
65  *
66  * Returns GPIO descriptor to use with Linux GPIO API, or one of the errno
67  * value on the error condition. If @flags is not NULL the function also fills
68  * in flags for the GPIO.
69  */
70 struct gpio_desc *of_get_named_gpiod_flags(struct device_node *np,
71 		     const char *propname, int index, enum of_gpio_flags *flags)
72 {
73 	struct of_phandle_args gpiospec;
74 	struct gpio_chip *chip;
75 	struct gpio_desc *desc;
76 	int ret;
77 
78 	ret = of_parse_phandle_with_args(np, propname, "#gpio-cells", index,
79 					 &gpiospec);
80 	if (ret) {
81 		pr_debug("%s: can't parse '%s' property of node '%s[%d]'\n",
82 			__func__, propname, np->full_name, index);
83 		return ERR_PTR(ret);
84 	}
85 
86 	chip = of_find_gpiochip_by_xlate(&gpiospec);
87 	if (!chip) {
88 		desc = ERR_PTR(-EPROBE_DEFER);
89 		goto out;
90 	}
91 
92 	desc = of_xlate_and_get_gpiod_flags(chip, &gpiospec, flags);
93 	if (IS_ERR(desc))
94 		goto out;
95 
96 	pr_debug("%s: parsed '%s' property of node '%s[%d]' - status (%d)\n",
97 		 __func__, propname, np->full_name, index,
98 		 PTR_ERR_OR_ZERO(desc));
99 
100 out:
101 	of_node_put(gpiospec.np);
102 
103 	return desc;
104 }
105 
106 int of_get_named_gpio_flags(struct device_node *np, const char *list_name,
107 			    int index, enum of_gpio_flags *flags)
108 {
109 	struct gpio_desc *desc;
110 
111 	desc = of_get_named_gpiod_flags(np, list_name, index, flags);
112 
113 	if (IS_ERR(desc))
114 		return PTR_ERR(desc);
115 	else
116 		return desc_to_gpio(desc);
117 }
118 EXPORT_SYMBOL(of_get_named_gpio_flags);
119 
120 struct gpio_desc *of_find_gpio(struct device *dev, const char *con_id,
121 			       unsigned int idx,
122 			       enum gpio_lookup_flags *flags)
123 {
124 	char prop_name[32]; /* 32 is max size of property name */
125 	enum of_gpio_flags of_flags;
126 	struct gpio_desc *desc;
127 	unsigned int i;
128 
129 	for (i = 0; i < ARRAY_SIZE(gpio_suffixes); i++) {
130 		if (con_id)
131 			snprintf(prop_name, sizeof(prop_name), "%s-%s", con_id,
132 				 gpio_suffixes[i]);
133 		else
134 			snprintf(prop_name, sizeof(prop_name), "%s",
135 				 gpio_suffixes[i]);
136 
137 		desc = of_get_named_gpiod_flags(dev->of_node, prop_name, idx,
138 						&of_flags);
139 		if (!IS_ERR(desc) || (PTR_ERR(desc) != -ENOENT))
140 			break;
141 	}
142 
143 	if (IS_ERR(desc))
144 		return desc;
145 
146 	if (of_flags & OF_GPIO_ACTIVE_LOW)
147 		*flags |= GPIO_ACTIVE_LOW;
148 
149 	if (of_flags & OF_GPIO_SINGLE_ENDED) {
150 		if (of_flags & OF_GPIO_OPEN_DRAIN)
151 			*flags |= GPIO_OPEN_DRAIN;
152 		else
153 			*flags |= GPIO_OPEN_SOURCE;
154 	}
155 
156 	if (of_flags & OF_GPIO_SLEEP_MAY_LOOSE_VALUE)
157 		*flags |= GPIO_SLEEP_MAY_LOOSE_VALUE;
158 
159 	return desc;
160 }
161 
162 /**
163  * of_parse_own_gpio() - Get a GPIO hog descriptor, names and flags for GPIO API
164  * @np:		device node to get GPIO from
165  * @chip:	GPIO chip whose hog is parsed
166  * @idx:	Index of the GPIO to parse
167  * @name:	GPIO line name
168  * @lflags:	gpio_lookup_flags - returned from of_find_gpio() or
169  *		of_parse_own_gpio()
170  * @dflags:	gpiod_flags - optional GPIO initialization flags
171  *
172  * Returns GPIO descriptor to use with Linux GPIO API, or one of the errno
173  * value on the error condition.
174  */
175 static struct gpio_desc *of_parse_own_gpio(struct device_node *np,
176 					   struct gpio_chip *chip,
177 					   unsigned int idx, const char **name,
178 					   enum gpio_lookup_flags *lflags,
179 					   enum gpiod_flags *dflags)
180 {
181 	struct device_node *chip_np;
182 	enum of_gpio_flags xlate_flags;
183 	struct of_phandle_args gpiospec;
184 	struct gpio_desc *desc;
185 	unsigned int i;
186 	u32 tmp;
187 	int ret;
188 
189 	chip_np = chip->of_node;
190 	if (!chip_np)
191 		return ERR_PTR(-EINVAL);
192 
193 	xlate_flags = 0;
194 	*lflags = 0;
195 	*dflags = 0;
196 
197 	ret = of_property_read_u32(chip_np, "#gpio-cells", &tmp);
198 	if (ret)
199 		return ERR_PTR(ret);
200 
201 	gpiospec.np = chip_np;
202 	gpiospec.args_count = tmp;
203 
204 	for (i = 0; i < tmp; i++) {
205 		ret = of_property_read_u32_index(np, "gpios", idx * tmp + i,
206 						 &gpiospec.args[i]);
207 		if (ret)
208 			return ERR_PTR(ret);
209 	}
210 
211 	desc = of_xlate_and_get_gpiod_flags(chip, &gpiospec, &xlate_flags);
212 	if (IS_ERR(desc))
213 		return desc;
214 
215 	if (xlate_flags & OF_GPIO_ACTIVE_LOW)
216 		*lflags |= GPIO_ACTIVE_LOW;
217 
218 	if (of_property_read_bool(np, "input"))
219 		*dflags |= GPIOD_IN;
220 	else if (of_property_read_bool(np, "output-low"))
221 		*dflags |= GPIOD_OUT_LOW;
222 	else if (of_property_read_bool(np, "output-high"))
223 		*dflags |= GPIOD_OUT_HIGH;
224 	else {
225 		pr_warn("GPIO line %d (%s): no hogging state specified, bailing out\n",
226 			desc_to_gpio(desc), np->name);
227 		return ERR_PTR(-EINVAL);
228 	}
229 
230 	if (name && of_property_read_string(np, "line-name", name))
231 		*name = np->name;
232 
233 	return desc;
234 }
235 
236 /**
237  * of_gpiochip_scan_gpios - Scan gpio-controller for gpio definitions
238  * @chip:	gpio chip to act on
239  *
240  * This is only used by of_gpiochip_add to request/set GPIO initial
241  * configuration.
242  * It returns error if it fails otherwise 0 on success.
243  */
244 static int of_gpiochip_scan_gpios(struct gpio_chip *chip)
245 {
246 	struct gpio_desc *desc = NULL;
247 	struct device_node *np;
248 	const char *name;
249 	enum gpio_lookup_flags lflags;
250 	enum gpiod_flags dflags;
251 	unsigned int i;
252 	int ret;
253 
254 	for_each_available_child_of_node(chip->of_node, np) {
255 		if (!of_property_read_bool(np, "gpio-hog"))
256 			continue;
257 
258 		for (i = 0;; i++) {
259 			desc = of_parse_own_gpio(np, chip, i, &name, &lflags,
260 						 &dflags);
261 			if (IS_ERR(desc))
262 				break;
263 
264 			ret = gpiod_hog(desc, name, lflags, dflags);
265 			if (ret < 0) {
266 				of_node_put(np);
267 				return ret;
268 			}
269 		}
270 	}
271 
272 	return 0;
273 }
274 
275 /**
276  * of_gpio_simple_xlate - translate gpio_spec to the GPIO number and flags
277  * @gc:		pointer to the gpio_chip structure
278  * @np:		device node of the GPIO chip
279  * @gpio_spec:	gpio specifier as found in the device tree
280  * @flags:	a flags pointer to fill in
281  *
282  * This is simple translation function, suitable for the most 1:1 mapped
283  * gpio chips. This function performs only one sanity check: whether gpio
284  * is less than ngpios (that is specified in the gpio_chip).
285  */
286 int of_gpio_simple_xlate(struct gpio_chip *gc,
287 			 const struct of_phandle_args *gpiospec, u32 *flags)
288 {
289 	/*
290 	 * We're discouraging gpio_cells < 2, since that way you'll have to
291 	 * write your own xlate function (that will have to retrieve the GPIO
292 	 * number and the flags from a single gpio cell -- this is possible,
293 	 * but not recommended).
294 	 */
295 	if (gc->of_gpio_n_cells < 2) {
296 		WARN_ON(1);
297 		return -EINVAL;
298 	}
299 
300 	if (WARN_ON(gpiospec->args_count < gc->of_gpio_n_cells))
301 		return -EINVAL;
302 
303 	if (gpiospec->args[0] >= gc->ngpio)
304 		return -EINVAL;
305 
306 	if (flags)
307 		*flags = gpiospec->args[1];
308 
309 	return gpiospec->args[0];
310 }
311 EXPORT_SYMBOL(of_gpio_simple_xlate);
312 
313 /**
314  * of_mm_gpiochip_add_data - Add memory mapped GPIO chip (bank)
315  * @np:		device node of the GPIO chip
316  * @mm_gc:	pointer to the of_mm_gpio_chip allocated structure
317  * @data:	driver data to store in the struct gpio_chip
318  *
319  * To use this function you should allocate and fill mm_gc with:
320  *
321  * 1) In the gpio_chip structure:
322  *    - all the callbacks
323  *    - of_gpio_n_cells
324  *    - of_xlate callback (optional)
325  *
326  * 3) In the of_mm_gpio_chip structure:
327  *    - save_regs callback (optional)
328  *
329  * If succeeded, this function will map bank's memory and will
330  * do all necessary work for you. Then you'll able to use .regs
331  * to manage GPIOs from the callbacks.
332  */
333 int of_mm_gpiochip_add_data(struct device_node *np,
334 			    struct of_mm_gpio_chip *mm_gc,
335 			    void *data)
336 {
337 	int ret = -ENOMEM;
338 	struct gpio_chip *gc = &mm_gc->gc;
339 
340 	gc->label = kstrdup(np->full_name, GFP_KERNEL);
341 	if (!gc->label)
342 		goto err0;
343 
344 	mm_gc->regs = of_iomap(np, 0);
345 	if (!mm_gc->regs)
346 		goto err1;
347 
348 	gc->base = -1;
349 
350 	if (mm_gc->save_regs)
351 		mm_gc->save_regs(mm_gc);
352 
353 	mm_gc->gc.of_node = np;
354 
355 	ret = gpiochip_add_data(gc, data);
356 	if (ret)
357 		goto err2;
358 
359 	return 0;
360 err2:
361 	iounmap(mm_gc->regs);
362 err1:
363 	kfree(gc->label);
364 err0:
365 	pr_err("%s: GPIO chip registration failed with status %d\n",
366 	       np->full_name, ret);
367 	return ret;
368 }
369 EXPORT_SYMBOL(of_mm_gpiochip_add_data);
370 
371 /**
372  * of_mm_gpiochip_remove - Remove memory mapped GPIO chip (bank)
373  * @mm_gc:	pointer to the of_mm_gpio_chip allocated structure
374  */
375 void of_mm_gpiochip_remove(struct of_mm_gpio_chip *mm_gc)
376 {
377 	struct gpio_chip *gc = &mm_gc->gc;
378 
379 	if (!mm_gc)
380 		return;
381 
382 	gpiochip_remove(gc);
383 	iounmap(mm_gc->regs);
384 	kfree(gc->label);
385 }
386 EXPORT_SYMBOL(of_mm_gpiochip_remove);
387 
388 #ifdef CONFIG_PINCTRL
389 static int of_gpiochip_add_pin_range(struct gpio_chip *chip)
390 {
391 	struct device_node *np = chip->of_node;
392 	struct of_phandle_args pinspec;
393 	struct pinctrl_dev *pctldev;
394 	int index = 0, ret;
395 	const char *name;
396 	static const char group_names_propname[] = "gpio-ranges-group-names";
397 	struct property *group_names;
398 
399 	if (!np)
400 		return 0;
401 
402 	group_names = of_find_property(np, group_names_propname, NULL);
403 
404 	for (;; index++) {
405 		ret = of_parse_phandle_with_fixed_args(np, "gpio-ranges", 3,
406 				index, &pinspec);
407 		if (ret)
408 			break;
409 
410 		pctldev = of_pinctrl_get(pinspec.np);
411 		of_node_put(pinspec.np);
412 		if (!pctldev)
413 			return -EPROBE_DEFER;
414 
415 		if (pinspec.args[2]) {
416 			if (group_names) {
417 				of_property_read_string_index(np,
418 						group_names_propname,
419 						index, &name);
420 				if (strlen(name)) {
421 					pr_err("%s: Group name of numeric GPIO ranges must be the empty string.\n",
422 						np->full_name);
423 					break;
424 				}
425 			}
426 			/* npins != 0: linear range */
427 			ret = gpiochip_add_pin_range(chip,
428 					pinctrl_dev_get_devname(pctldev),
429 					pinspec.args[0],
430 					pinspec.args[1],
431 					pinspec.args[2]);
432 			if (ret)
433 				return ret;
434 		} else {
435 			/* npins == 0: special range */
436 			if (pinspec.args[1]) {
437 				pr_err("%s: Illegal gpio-range format.\n",
438 					np->full_name);
439 				break;
440 			}
441 
442 			if (!group_names) {
443 				pr_err("%s: GPIO group range requested but no %s property.\n",
444 					np->full_name, group_names_propname);
445 				break;
446 			}
447 
448 			ret = of_property_read_string_index(np,
449 						group_names_propname,
450 						index, &name);
451 			if (ret)
452 				break;
453 
454 			if (!strlen(name)) {
455 				pr_err("%s: Group name of GPIO group range cannot be the empty string.\n",
456 				np->full_name);
457 				break;
458 			}
459 
460 			ret = gpiochip_add_pingroup_range(chip, pctldev,
461 						pinspec.args[0], name);
462 			if (ret)
463 				return ret;
464 		}
465 	}
466 
467 	return 0;
468 }
469 
470 #else
471 static int of_gpiochip_add_pin_range(struct gpio_chip *chip) { return 0; }
472 #endif
473 
474 int of_gpiochip_add(struct gpio_chip *chip)
475 {
476 	int status;
477 
478 	if ((!chip->of_node) && (chip->parent))
479 		chip->of_node = chip->parent->of_node;
480 
481 	if (!chip->of_node)
482 		return 0;
483 
484 	if (!chip->of_xlate) {
485 		chip->of_gpio_n_cells = 2;
486 		chip->of_xlate = of_gpio_simple_xlate;
487 	}
488 
489 	if (chip->of_gpio_n_cells > MAX_PHANDLE_ARGS)
490 		return -EINVAL;
491 
492 	status = of_gpiochip_add_pin_range(chip);
493 	if (status)
494 		return status;
495 
496 	/* If the chip defines names itself, these take precedence */
497 	if (!chip->names)
498 		devprop_gpiochip_set_names(chip);
499 
500 	of_node_get(chip->of_node);
501 
502 	return of_gpiochip_scan_gpios(chip);
503 }
504 
505 void of_gpiochip_remove(struct gpio_chip *chip)
506 {
507 	gpiochip_remove_pin_ranges(chip);
508 	of_node_put(chip->of_node);
509 }
510