xref: /openbmc/linux/drivers/gpio/gpiolib-of.c (revision ae3473231e77a3f1909d48cd144cebe5e1d049b3)
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_ACTIVE_LOW)
151 			*flags |= GPIO_OPEN_DRAIN;
152 		else
153 			*flags |= GPIO_OPEN_SOURCE;
154 	}
155 
156 	return desc;
157 }
158 
159 /**
160  * of_parse_own_gpio() - Get a GPIO hog descriptor, names and flags for GPIO API
161  * @np:		device node to get GPIO from
162  * @chip:	GPIO chip whose hog is parsed
163  * @name:	GPIO line name
164  * @lflags:	gpio_lookup_flags - returned from of_find_gpio() or
165  *		of_parse_own_gpio()
166  * @dflags:	gpiod_flags - optional GPIO initialization flags
167  *
168  * Returns GPIO descriptor to use with Linux GPIO API, or one of the errno
169  * value on the error condition.
170  */
171 static struct gpio_desc *of_parse_own_gpio(struct device_node *np,
172 					   struct gpio_chip *chip,
173 					   const char **name,
174 					   enum gpio_lookup_flags *lflags,
175 					   enum gpiod_flags *dflags)
176 {
177 	struct device_node *chip_np;
178 	enum of_gpio_flags xlate_flags;
179 	struct of_phandle_args gpiospec;
180 	struct gpio_desc *desc;
181 	u32 tmp;
182 	int ret;
183 
184 	chip_np = chip->of_node;
185 	if (!chip_np)
186 		return ERR_PTR(-EINVAL);
187 
188 	xlate_flags = 0;
189 	*lflags = 0;
190 	*dflags = 0;
191 
192 	ret = of_property_read_u32(chip_np, "#gpio-cells", &tmp);
193 	if (ret)
194 		return ERR_PTR(ret);
195 
196 	gpiospec.np = chip_np;
197 	gpiospec.args_count = tmp;
198 
199 	ret = of_property_read_u32_array(np, "gpios", gpiospec.args, tmp);
200 	if (ret)
201 		return ERR_PTR(ret);
202 
203 	desc = of_xlate_and_get_gpiod_flags(chip, &gpiospec, &xlate_flags);
204 	if (IS_ERR(desc))
205 		return desc;
206 
207 	if (xlate_flags & OF_GPIO_ACTIVE_LOW)
208 		*lflags |= GPIO_ACTIVE_LOW;
209 
210 	if (of_property_read_bool(np, "input"))
211 		*dflags |= GPIOD_IN;
212 	else if (of_property_read_bool(np, "output-low"))
213 		*dflags |= GPIOD_OUT_LOW;
214 	else if (of_property_read_bool(np, "output-high"))
215 		*dflags |= GPIOD_OUT_HIGH;
216 	else {
217 		pr_warn("GPIO line %d (%s): no hogging state specified, bailing out\n",
218 			desc_to_gpio(desc), np->name);
219 		return ERR_PTR(-EINVAL);
220 	}
221 
222 	if (name && of_property_read_string(np, "line-name", name))
223 		*name = np->name;
224 
225 	return desc;
226 }
227 
228 /**
229  * of_gpiochip_scan_gpios - Scan gpio-controller for gpio definitions
230  * @chip:	gpio chip to act on
231  *
232  * This is only used by of_gpiochip_add to request/set GPIO initial
233  * configuration.
234  * It retures error if it fails otherwise 0 on success.
235  */
236 static int of_gpiochip_scan_gpios(struct gpio_chip *chip)
237 {
238 	struct gpio_desc *desc = NULL;
239 	struct device_node *np;
240 	const char *name;
241 	enum gpio_lookup_flags lflags;
242 	enum gpiod_flags dflags;
243 	int ret;
244 
245 	for_each_available_child_of_node(chip->of_node, np) {
246 		if (!of_property_read_bool(np, "gpio-hog"))
247 			continue;
248 
249 		desc = of_parse_own_gpio(np, chip, &name, &lflags, &dflags);
250 		if (IS_ERR(desc))
251 			continue;
252 
253 		ret = gpiod_hog(desc, name, lflags, dflags);
254 		if (ret < 0) {
255 			of_node_put(np);
256 			return ret;
257 		}
258 	}
259 
260 	return 0;
261 }
262 
263 /**
264  * of_gpio_simple_xlate - translate gpio_spec to the GPIO number and flags
265  * @gc:		pointer to the gpio_chip structure
266  * @np:		device node of the GPIO chip
267  * @gpio_spec:	gpio specifier as found in the device tree
268  * @flags:	a flags pointer to fill in
269  *
270  * This is simple translation function, suitable for the most 1:1 mapped
271  * gpio chips. This function performs only one sanity check: whether gpio
272  * is less than ngpios (that is specified in the gpio_chip).
273  */
274 int of_gpio_simple_xlate(struct gpio_chip *gc,
275 			 const struct of_phandle_args *gpiospec, u32 *flags)
276 {
277 	/*
278 	 * We're discouraging gpio_cells < 2, since that way you'll have to
279 	 * write your own xlate function (that will have to retrieve the GPIO
280 	 * number and the flags from a single gpio cell -- this is possible,
281 	 * but not recommended).
282 	 */
283 	if (gc->of_gpio_n_cells < 2) {
284 		WARN_ON(1);
285 		return -EINVAL;
286 	}
287 
288 	if (WARN_ON(gpiospec->args_count < gc->of_gpio_n_cells))
289 		return -EINVAL;
290 
291 	if (gpiospec->args[0] >= gc->ngpio)
292 		return -EINVAL;
293 
294 	if (flags)
295 		*flags = gpiospec->args[1];
296 
297 	return gpiospec->args[0];
298 }
299 EXPORT_SYMBOL(of_gpio_simple_xlate);
300 
301 /**
302  * of_mm_gpiochip_add_data - Add memory mapped GPIO chip (bank)
303  * @np:		device node of the GPIO chip
304  * @mm_gc:	pointer to the of_mm_gpio_chip allocated structure
305  * @data:	driver data to store in the struct gpio_chip
306  *
307  * To use this function you should allocate and fill mm_gc with:
308  *
309  * 1) In the gpio_chip structure:
310  *    - all the callbacks
311  *    - of_gpio_n_cells
312  *    - of_xlate callback (optional)
313  *
314  * 3) In the of_mm_gpio_chip structure:
315  *    - save_regs callback (optional)
316  *
317  * If succeeded, this function will map bank's memory and will
318  * do all necessary work for you. Then you'll able to use .regs
319  * to manage GPIOs from the callbacks.
320  */
321 int of_mm_gpiochip_add_data(struct device_node *np,
322 			    struct of_mm_gpio_chip *mm_gc,
323 			    void *data)
324 {
325 	int ret = -ENOMEM;
326 	struct gpio_chip *gc = &mm_gc->gc;
327 
328 	gc->label = kstrdup(np->full_name, GFP_KERNEL);
329 	if (!gc->label)
330 		goto err0;
331 
332 	mm_gc->regs = of_iomap(np, 0);
333 	if (!mm_gc->regs)
334 		goto err1;
335 
336 	gc->base = -1;
337 
338 	if (mm_gc->save_regs)
339 		mm_gc->save_regs(mm_gc);
340 
341 	mm_gc->gc.of_node = np;
342 
343 	ret = gpiochip_add_data(gc, data);
344 	if (ret)
345 		goto err2;
346 
347 	return 0;
348 err2:
349 	iounmap(mm_gc->regs);
350 err1:
351 	kfree(gc->label);
352 err0:
353 	pr_err("%s: GPIO chip registration failed with status %d\n",
354 	       np->full_name, ret);
355 	return ret;
356 }
357 EXPORT_SYMBOL(of_mm_gpiochip_add_data);
358 
359 /**
360  * of_mm_gpiochip_remove - Remove memory mapped GPIO chip (bank)
361  * @mm_gc:	pointer to the of_mm_gpio_chip allocated structure
362  */
363 void of_mm_gpiochip_remove(struct of_mm_gpio_chip *mm_gc)
364 {
365 	struct gpio_chip *gc = &mm_gc->gc;
366 
367 	if (!mm_gc)
368 		return;
369 
370 	gpiochip_remove(gc);
371 	iounmap(mm_gc->regs);
372 	kfree(gc->label);
373 }
374 EXPORT_SYMBOL(of_mm_gpiochip_remove);
375 
376 #ifdef CONFIG_PINCTRL
377 static int of_gpiochip_add_pin_range(struct gpio_chip *chip)
378 {
379 	struct device_node *np = chip->of_node;
380 	struct of_phandle_args pinspec;
381 	struct pinctrl_dev *pctldev;
382 	int index = 0, ret;
383 	const char *name;
384 	static const char group_names_propname[] = "gpio-ranges-group-names";
385 	struct property *group_names;
386 
387 	if (!np)
388 		return 0;
389 
390 	group_names = of_find_property(np, group_names_propname, NULL);
391 
392 	for (;; index++) {
393 		ret = of_parse_phandle_with_fixed_args(np, "gpio-ranges", 3,
394 				index, &pinspec);
395 		if (ret)
396 			break;
397 
398 		pctldev = of_pinctrl_get(pinspec.np);
399 		of_node_put(pinspec.np);
400 		if (!pctldev)
401 			return -EPROBE_DEFER;
402 
403 		if (pinspec.args[2]) {
404 			if (group_names) {
405 				of_property_read_string_index(np,
406 						group_names_propname,
407 						index, &name);
408 				if (strlen(name)) {
409 					pr_err("%s: Group name of numeric GPIO ranges must be the empty string.\n",
410 						np->full_name);
411 					break;
412 				}
413 			}
414 			/* npins != 0: linear range */
415 			ret = gpiochip_add_pin_range(chip,
416 					pinctrl_dev_get_devname(pctldev),
417 					pinspec.args[0],
418 					pinspec.args[1],
419 					pinspec.args[2]);
420 			if (ret)
421 				return ret;
422 		} else {
423 			/* npins == 0: special range */
424 			if (pinspec.args[1]) {
425 				pr_err("%s: Illegal gpio-range format.\n",
426 					np->full_name);
427 				break;
428 			}
429 
430 			if (!group_names) {
431 				pr_err("%s: GPIO group range requested but no %s property.\n",
432 					np->full_name, group_names_propname);
433 				break;
434 			}
435 
436 			ret = of_property_read_string_index(np,
437 						group_names_propname,
438 						index, &name);
439 			if (ret)
440 				break;
441 
442 			if (!strlen(name)) {
443 				pr_err("%s: Group name of GPIO group range cannot be the empty string.\n",
444 				np->full_name);
445 				break;
446 			}
447 
448 			ret = gpiochip_add_pingroup_range(chip, pctldev,
449 						pinspec.args[0], name);
450 			if (ret)
451 				return ret;
452 		}
453 	}
454 
455 	return 0;
456 }
457 
458 #else
459 static int of_gpiochip_add_pin_range(struct gpio_chip *chip) { return 0; }
460 #endif
461 
462 int of_gpiochip_add(struct gpio_chip *chip)
463 {
464 	int status;
465 
466 	if ((!chip->of_node) && (chip->parent))
467 		chip->of_node = chip->parent->of_node;
468 
469 	if (!chip->of_node)
470 		return 0;
471 
472 	if (!chip->of_xlate) {
473 		chip->of_gpio_n_cells = 2;
474 		chip->of_xlate = of_gpio_simple_xlate;
475 	}
476 
477 	if (chip->of_gpio_n_cells > MAX_PHANDLE_ARGS)
478 		return -EINVAL;
479 
480 	status = of_gpiochip_add_pin_range(chip);
481 	if (status)
482 		return status;
483 
484 	/* If the chip defines names itself, these take precedence */
485 	if (!chip->names)
486 		devprop_gpiochip_set_names(chip);
487 
488 	of_node_get(chip->of_node);
489 
490 	return of_gpiochip_scan_gpios(chip);
491 }
492 
493 void of_gpiochip_remove(struct gpio_chip *chip)
494 {
495 	gpiochip_remove_pin_ranges(chip);
496 	of_node_put(chip->of_node);
497 }
498