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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
29static 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
37static 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
43static 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
59static void of_gpio_flags_quirks(struct device_node *np,
60 enum of_gpio_flags *flags)
61{
62 /*
63 * Some GPIO fixed regulator quirks.
64 * Note that active low is the default.
65 */
66 if (IS_ENABLED(CONFIG_REGULATOR) &&
67 (of_device_is_compatible(np, "reg-fixed-voltage") ||
68 of_device_is_compatible(np, "regulator-gpio"))) {
69 /*
70 * The regulator GPIO handles are specified such that the
71 * presence or absence of "enable-active-high" solely controls
72 * the polarity of the GPIO line. Any phandle flags must
73 * be actively ignored.
74 */
75 if (*flags & OF_GPIO_ACTIVE_LOW) {
76 pr_warn("%s GPIO handle specifies active low - ignored\n",
77 of_node_full_name(np));
78 *flags &= ~OF_GPIO_ACTIVE_LOW;
79 }
80 if (!of_property_read_bool(np, "enable-active-high"))
81 *flags |= OF_GPIO_ACTIVE_LOW;
82 }
83 /*
84 * Legacy open drain handling for fixed voltage regulators.
85 */
86 if (IS_ENABLED(CONFIG_REGULATOR) &&
87 of_device_is_compatible(np, "reg-fixed-voltage") &&
88 of_property_read_bool(np, "gpio-open-drain")) {
89 *flags |= (OF_GPIO_SINGLE_ENDED | OF_GPIO_OPEN_DRAIN);
90 pr_info("%s uses legacy open drain flag - update the DTS if you can\n",
91 of_node_full_name(np));
92 }
93}
94
95/**
96 * of_get_named_gpiod_flags() - Get a GPIO descriptor and flags for GPIO API
97 * @np: device node to get GPIO from
98 * @propname: property name containing gpio specifier(s)
99 * @index: index of the GPIO
100 * @flags: a flags pointer to fill in
101 *
102 * Returns GPIO descriptor to use with Linux GPIO API, or one of the errno
103 * value on the error condition. If @flags is not NULL the function also fills
104 * in flags for the GPIO.
105 */
106struct gpio_desc *of_get_named_gpiod_flags(struct device_node *np,
107 const char *propname, int index, enum of_gpio_flags *flags)
108{
109 struct of_phandle_args gpiospec;
110 struct gpio_chip *chip;
111 struct gpio_desc *desc;
112 int ret;
113
114 ret = of_parse_phandle_with_args_map(np, propname, "gpio", index,
115 &gpiospec);
116 if (ret) {
117 pr_debug("%s: can't parse '%s' property of node '%pOF[%d]'\n",
118 __func__, propname, np, index);
119 return ERR_PTR(ret);
120 }
121
122 chip = of_find_gpiochip_by_xlate(&gpiospec);
123 if (!chip) {
124 desc = ERR_PTR(-EPROBE_DEFER);
125 goto out;
126 }
127
128 desc = of_xlate_and_get_gpiod_flags(chip, &gpiospec, flags);
129 if (IS_ERR(desc))
130 goto out;
131
132 if (flags)
133 of_gpio_flags_quirks(np, flags);
134
135 pr_debug("%s: parsed '%s' property of node '%pOF[%d]' - status (%d)\n",
136 __func__, propname, np, index,
137 PTR_ERR_OR_ZERO(desc));
138
139out:
140 of_node_put(gpiospec.np);
141
142 return desc;
143}
144
145int of_get_named_gpio_flags(struct device_node *np, const char *list_name,
146 int index, enum of_gpio_flags *flags)
147{
148 struct gpio_desc *desc;
149
150 desc = of_get_named_gpiod_flags(np, list_name, index, flags);
151
152 if (IS_ERR(desc))
153 return PTR_ERR(desc);
154 else
155 return desc_to_gpio(desc);
156}
157EXPORT_SYMBOL(of_get_named_gpio_flags);
158
159/*
160 * The SPI GPIO bindings happened before we managed to establish that GPIO
161 * properties should be named "foo-gpios" so we have this special kludge for
162 * them.
163 */
164static struct gpio_desc *of_find_spi_gpio(struct device *dev, const char *con_id,
165 enum of_gpio_flags *of_flags)
166{
167 char prop_name[32]; /* 32 is max size of property name */
168 struct device_node *np = dev->of_node;
169 struct gpio_desc *desc;
170
171 /*
172 * Hopefully the compiler stubs the rest of the function if this
173 * is false.
174 */
175 if (!IS_ENABLED(CONFIG_SPI_MASTER))
176 return ERR_PTR(-ENOENT);
177
178 /* Allow this specifically for "spi-gpio" devices */
179 if (!of_device_is_compatible(np, "spi-gpio") || !con_id)
180 return ERR_PTR(-ENOENT);
181
182 /* Will be "gpio-sck", "gpio-mosi" or "gpio-miso" */
183 snprintf(prop_name, sizeof(prop_name), "%s-%s", "gpio", con_id);
184
185 desc = of_get_named_gpiod_flags(np, prop_name, 0, of_flags);
186 return desc;
187}
188
189/*
190 * Some regulator bindings happened before we managed to establish that GPIO
191 * properties should be named "foo-gpios" so we have this special kludge for
192 * them.
193 */
194static struct gpio_desc *of_find_regulator_gpio(struct device *dev, const char *con_id,
195 enum of_gpio_flags *of_flags)
196{
197 /* These are the connection IDs we accept as legacy GPIO phandles */
198 const char *whitelist[] = {
199 "wlf,ldoena", /* Arizona */
200 "wlf,ldo1ena", /* WM8994 */
201 "wlf,ldo2ena", /* WM8994 */
202 };
203 struct device_node *np = dev->of_node;
204 struct gpio_desc *desc;
205 int i;
206
207 if (!IS_ENABLED(CONFIG_REGULATOR))
208 return ERR_PTR(-ENOENT);
209
210 if (!con_id)
211 return ERR_PTR(-ENOENT);
212
213 for (i = 0; i < ARRAY_SIZE(whitelist); i++)
214 if (!strcmp(con_id, whitelist[i]))
215 break;
216
217 if (i == ARRAY_SIZE(whitelist))
218 return ERR_PTR(-ENOENT);
219
220 desc = of_get_named_gpiod_flags(np, con_id, 0, of_flags);
221 return desc;
222}
223
224struct gpio_desc *of_find_gpio(struct device *dev, const char *con_id,
225 unsigned int idx,
226 enum gpio_lookup_flags *flags)
227{
228 char prop_name[32]; /* 32 is max size of property name */
229 enum of_gpio_flags of_flags;
230 struct gpio_desc *desc;
231 unsigned int i;
232
233 /* Try GPIO property "foo-gpios" and "foo-gpio" */
234 for (i = 0; i < ARRAY_SIZE(gpio_suffixes); i++) {
235 if (con_id)
236 snprintf(prop_name, sizeof(prop_name), "%s-%s", con_id,
237 gpio_suffixes[i]);
238 else
239 snprintf(prop_name, sizeof(prop_name), "%s",
240 gpio_suffixes[i]);
241
242 desc = of_get_named_gpiod_flags(dev->of_node, prop_name, idx,
243 &of_flags);
244 /*
245 * -EPROBE_DEFER in our case means that we found a
246 * valid GPIO property, but no controller has been
247 * registered so far.
248 *
249 * This means we don't need to look any further for
250 * alternate name conventions, and we should really
251 * preserve the return code for our user to be able to
252 * retry probing later.
253 */
254 if (IS_ERR(desc) && PTR_ERR(desc) == -EPROBE_DEFER)
255 return desc;
256
257 if (!IS_ERR(desc) || (PTR_ERR(desc) != -ENOENT))
258 break;
259 }
260
261 /* Special handling for SPI GPIOs if used */
262 if (IS_ERR(desc))
263 desc = of_find_spi_gpio(dev, con_id, &of_flags);
264
265 /* Special handling for regulator GPIOs if used */
266 if (IS_ERR(desc) && PTR_ERR(desc) != -EPROBE_DEFER)
267 desc = of_find_regulator_gpio(dev, con_id, &of_flags);
268
269 if (IS_ERR(desc))
270 return desc;
271
272 if (of_flags & OF_GPIO_ACTIVE_LOW)
273 *flags |= GPIO_ACTIVE_LOW;
274
275 if (of_flags & OF_GPIO_SINGLE_ENDED) {
276 if (of_flags & OF_GPIO_OPEN_DRAIN)
277 *flags |= GPIO_OPEN_DRAIN;
278 else
279 *flags |= GPIO_OPEN_SOURCE;
280 }
281
282 if (of_flags & OF_GPIO_TRANSITORY)
283 *flags |= GPIO_TRANSITORY;
284
285 return desc;
286}
287
288/**
289 * of_parse_own_gpio() - Get a GPIO hog descriptor, names and flags for GPIO API
290 * @np: device node to get GPIO from
291 * @chip: GPIO chip whose hog is parsed
292 * @idx: Index of the GPIO to parse
293 * @name: GPIO line name
294 * @lflags: gpio_lookup_flags - returned from of_find_gpio() or
295 * of_parse_own_gpio()
296 * @dflags: gpiod_flags - optional GPIO initialization flags
297 *
298 * Returns GPIO descriptor to use with Linux GPIO API, or one of the errno
299 * value on the error condition.
300 */
301static struct gpio_desc *of_parse_own_gpio(struct device_node *np,
302 struct gpio_chip *chip,
303 unsigned int idx, const char **name,
304 enum gpio_lookup_flags *lflags,
305 enum gpiod_flags *dflags)
306{
307 struct device_node *chip_np;
308 enum of_gpio_flags xlate_flags;
309 struct of_phandle_args gpiospec;
310 struct gpio_desc *desc;
311 unsigned int i;
312 u32 tmp;
313 int ret;
314
315 chip_np = chip->of_node;
316 if (!chip_np)
317 return ERR_PTR(-EINVAL);
318
319 xlate_flags = 0;
320 *lflags = 0;
321 *dflags = 0;
322
323 ret = of_property_read_u32(chip_np, "#gpio-cells", &tmp);
324 if (ret)
325 return ERR_PTR(ret);
326
327 gpiospec.np = chip_np;
328 gpiospec.args_count = tmp;
329
330 for (i = 0; i < tmp; i++) {
331 ret = of_property_read_u32_index(np, "gpios", idx * tmp + i,
332 &gpiospec.args[i]);
333 if (ret)
334 return ERR_PTR(ret);
335 }
336
337 desc = of_xlate_and_get_gpiod_flags(chip, &gpiospec, &xlate_flags);
338 if (IS_ERR(desc))
339 return desc;
340
341 if (xlate_flags & OF_GPIO_ACTIVE_LOW)
342 *lflags |= GPIO_ACTIVE_LOW;
343 if (xlate_flags & OF_GPIO_TRANSITORY)
344 *lflags |= GPIO_TRANSITORY;
345
346 if (of_property_read_bool(np, "input"))
347 *dflags |= GPIOD_IN;
348 else if (of_property_read_bool(np, "output-low"))
349 *dflags |= GPIOD_OUT_LOW;
350 else if (of_property_read_bool(np, "output-high"))
351 *dflags |= GPIOD_OUT_HIGH;
352 else {
353 pr_warn("GPIO line %d (%s): no hogging state specified, bailing out\n",
354 desc_to_gpio(desc), np->name);
355 return ERR_PTR(-EINVAL);
356 }
357
358 if (name && of_property_read_string(np, "line-name", name))
359 *name = np->name;
360
361 return desc;
362}
363
364/**
365 * of_gpiochip_scan_gpios - Scan gpio-controller for gpio definitions
366 * @chip: gpio chip to act on
367 *
368 * This is only used by of_gpiochip_add to request/set GPIO initial
369 * configuration.
370 * It returns error if it fails otherwise 0 on success.
371 */
372static int of_gpiochip_scan_gpios(struct gpio_chip *chip)
373{
374 struct gpio_desc *desc = NULL;
375 struct device_node *np;
376 const char *name;
377 enum gpio_lookup_flags lflags;
378 enum gpiod_flags dflags;
379 unsigned int i;
380 int ret;
381
382 for_each_available_child_of_node(chip->of_node, np) {
383 if (!of_property_read_bool(np, "gpio-hog"))
384 continue;
385
386 for (i = 0;; i++) {
387 desc = of_parse_own_gpio(np, chip, i, &name, &lflags,
388 &dflags);
389 if (IS_ERR(desc))
390 break;
391
392 ret = gpiod_hog(desc, name, lflags, dflags);
393 if (ret < 0) {
394 of_node_put(np);
395 return ret;
396 }
397 }
398 }
399
400 return 0;
401}
402
403/**
404 * of_gpio_simple_xlate - translate gpiospec to the GPIO number and flags
405 * @gc: pointer to the gpio_chip structure
406 * @gpiospec: GPIO specifier as found in the device tree
407 * @flags: a flags pointer to fill in
408 *
409 * This is simple translation function, suitable for the most 1:1 mapped
410 * GPIO chips. This function performs only one sanity check: whether GPIO
411 * is less than ngpios (that is specified in the gpio_chip).
412 */
413int of_gpio_simple_xlate(struct gpio_chip *gc,
414 const struct of_phandle_args *gpiospec, u32 *flags)
415{
416 /*
417 * We're discouraging gpio_cells < 2, since that way you'll have to
418 * write your own xlate function (that will have to retrieve the GPIO
419 * number and the flags from a single gpio cell -- this is possible,
420 * but not recommended).
421 */
422 if (gc->of_gpio_n_cells < 2) {
423 WARN_ON(1);
424 return -EINVAL;
425 }
426
427 if (WARN_ON(gpiospec->args_count < gc->of_gpio_n_cells))
428 return -EINVAL;
429
430 if (gpiospec->args[0] >= gc->ngpio)
431 return -EINVAL;
432
433 if (flags)
434 *flags = gpiospec->args[1];
435
436 return gpiospec->args[0];
437}
438EXPORT_SYMBOL(of_gpio_simple_xlate);
439
440/**
441 * of_mm_gpiochip_add_data - Add memory mapped GPIO chip (bank)
442 * @np: device node of the GPIO chip
443 * @mm_gc: pointer to the of_mm_gpio_chip allocated structure
444 * @data: driver data to store in the struct gpio_chip
445 *
446 * To use this function you should allocate and fill mm_gc with:
447 *
448 * 1) In the gpio_chip structure:
449 * - all the callbacks
450 * - of_gpio_n_cells
451 * - of_xlate callback (optional)
452 *
453 * 3) In the of_mm_gpio_chip structure:
454 * - save_regs callback (optional)
455 *
456 * If succeeded, this function will map bank's memory and will
457 * do all necessary work for you. Then you'll able to use .regs
458 * to manage GPIOs from the callbacks.
459 */
460int of_mm_gpiochip_add_data(struct device_node *np,
461 struct of_mm_gpio_chip *mm_gc,
462 void *data)
463{
464 int ret = -ENOMEM;
465 struct gpio_chip *gc = &mm_gc->gc;
466
467 gc->label = kasprintf(GFP_KERNEL, "%pOF", np);
468 if (!gc->label)
469 goto err0;
470
471 mm_gc->regs = of_iomap(np, 0);
472 if (!mm_gc->regs)
473 goto err1;
474
475 gc->base = -1;
476
477 if (mm_gc->save_regs)
478 mm_gc->save_regs(mm_gc);
479
480 mm_gc->gc.of_node = np;
481
482 ret = gpiochip_add_data(gc, data);
483 if (ret)
484 goto err2;
485
486 return 0;
487err2:
488 iounmap(mm_gc->regs);
489err1:
490 kfree(gc->label);
491err0:
492 pr_err("%pOF: GPIO chip registration failed with status %d\n", np, ret);
493 return ret;
494}
495EXPORT_SYMBOL(of_mm_gpiochip_add_data);
496
497/**
498 * of_mm_gpiochip_remove - Remove memory mapped GPIO chip (bank)
499 * @mm_gc: pointer to the of_mm_gpio_chip allocated structure
500 */
501void of_mm_gpiochip_remove(struct of_mm_gpio_chip *mm_gc)
502{
503 struct gpio_chip *gc = &mm_gc->gc;
504
505 if (!mm_gc)
506 return;
507
508 gpiochip_remove(gc);
509 iounmap(mm_gc->regs);
510 kfree(gc->label);
511}
512EXPORT_SYMBOL(of_mm_gpiochip_remove);
513
514static void of_gpiochip_init_valid_mask(struct gpio_chip *chip)
515{
516 int len, i;
517 u32 start, count;
518 struct device_node *np = chip->of_node;
519
520 len = of_property_count_u32_elems(np, "gpio-reserved-ranges");
521 if (len < 0 || len % 2 != 0)
522 return;
523
524 for (i = 0; i < len; i += 2) {
525 of_property_read_u32_index(np, "gpio-reserved-ranges",
526 i, &start);
527 of_property_read_u32_index(np, "gpio-reserved-ranges",
528 i + 1, &count);
529 if (start >= chip->ngpio || start + count >= chip->ngpio)
530 continue;
531
532 bitmap_clear(chip->valid_mask, start, count);
533 }
534};
535
536#ifdef CONFIG_PINCTRL
537static int of_gpiochip_add_pin_range(struct gpio_chip *chip)
538{
539 struct device_node *np = chip->of_node;
540 struct of_phandle_args pinspec;
541 struct pinctrl_dev *pctldev;
542 int index = 0, ret;
543 const char *name;
544 static const char group_names_propname[] = "gpio-ranges-group-names";
545 struct property *group_names;
546
547 if (!np)
548 return 0;
549
550 group_names = of_find_property(np, group_names_propname, NULL);
551
552 for (;; index++) {
553 ret = of_parse_phandle_with_fixed_args(np, "gpio-ranges", 3,
554 index, &pinspec);
555 if (ret)
556 break;
557
558 pctldev = of_pinctrl_get(pinspec.np);
559 of_node_put(pinspec.np);
560 if (!pctldev)
561 return -EPROBE_DEFER;
562
563 if (pinspec.args[2]) {
564 if (group_names) {
565 of_property_read_string_index(np,
566 group_names_propname,
567 index, &name);
568 if (strlen(name)) {
569 pr_err("%pOF: Group name of numeric GPIO ranges must be the empty string.\n",
570 np);
571 break;
572 }
573 }
574 /* npins != 0: linear range */
575 ret = gpiochip_add_pin_range(chip,
576 pinctrl_dev_get_devname(pctldev),
577 pinspec.args[0],
578 pinspec.args[1],
579 pinspec.args[2]);
580 if (ret)
581 return ret;
582 } else {
583 /* npins == 0: special range */
584 if (pinspec.args[1]) {
585 pr_err("%pOF: Illegal gpio-range format.\n",
586 np);
587 break;
588 }
589
590 if (!group_names) {
591 pr_err("%pOF: GPIO group range requested but no %s property.\n",
592 np, group_names_propname);
593 break;
594 }
595
596 ret = of_property_read_string_index(np,
597 group_names_propname,
598 index, &name);
599 if (ret)
600 break;
601
602 if (!strlen(name)) {
603 pr_err("%pOF: Group name of GPIO group range cannot be the empty string.\n",
604 np);
605 break;
606 }
607
608 ret = gpiochip_add_pingroup_range(chip, pctldev,
609 pinspec.args[0], name);
610 if (ret)
611 return ret;
612 }
613 }
614
615 return 0;
616}
617
618#else
619static int of_gpiochip_add_pin_range(struct gpio_chip *chip) { return 0; }
620#endif
621
622int of_gpiochip_add(struct gpio_chip *chip)
623{
624 int status;
625
626 if ((!chip->of_node) && (chip->parent))
627 chip->of_node = chip->parent->of_node;
628
629 if (!chip->of_node)
630 return 0;
631
632 if (!chip->of_xlate) {
633 chip->of_gpio_n_cells = 2;
634 chip->of_xlate = of_gpio_simple_xlate;
635 }
636
637 if (chip->of_gpio_n_cells > MAX_PHANDLE_ARGS)
638 return -EINVAL;
639
640 of_gpiochip_init_valid_mask(chip);
641
642 status = of_gpiochip_add_pin_range(chip);
643 if (status)
644 return status;
645
646 /* If the chip defines names itself, these take precedence */
647 if (!chip->names)
648 devprop_gpiochip_set_names(chip,
649 of_fwnode_handle(chip->of_node));
650
651 of_node_get(chip->of_node);
652
653 return of_gpiochip_scan_gpios(chip);
654}
655
656void of_gpiochip_remove(struct gpio_chip *chip)
657{
658 gpiochip_remove_pin_ranges(chip);
659 of_node_put(chip->of_node);
660}