xref: /linux/drivers/pinctrl/pinmux.c (revision 6fdcba32711044c35c0e1b094cbd8f3f0b4472c9)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Core driver for the pin muxing portions of the pin control subsystem
4  *
5  * Copyright (C) 2011-2012 ST-Ericsson SA
6  * Written on behalf of Linaro for ST-Ericsson
7  * Based on bits of regulator core, gpio core and clk core
8  *
9  * Author: Linus Walleij <linus.walleij@linaro.org>
10  *
11  * Copyright (C) 2012 NVIDIA CORPORATION. All rights reserved.
12  */
13 #define pr_fmt(fmt) "pinmux core: " fmt
14 
15 #include <linux/kernel.h>
16 #include <linux/module.h>
17 #include <linux/init.h>
18 #include <linux/device.h>
19 #include <linux/slab.h>
20 #include <linux/radix-tree.h>
21 #include <linux/err.h>
22 #include <linux/list.h>
23 #include <linux/string.h>
24 #include <linux/debugfs.h>
25 #include <linux/seq_file.h>
26 #include <linux/pinctrl/machine.h>
27 #include <linux/pinctrl/pinmux.h>
28 #include "core.h"
29 #include "pinmux.h"
30 
31 int pinmux_check_ops(struct pinctrl_dev *pctldev)
32 {
33 	const struct pinmux_ops *ops = pctldev->desc->pmxops;
34 	unsigned nfuncs;
35 	unsigned selector = 0;
36 
37 	/* Check that we implement required operations */
38 	if (!ops ||
39 	    !ops->get_functions_count ||
40 	    !ops->get_function_name ||
41 	    !ops->get_function_groups ||
42 	    !ops->set_mux) {
43 		dev_err(pctldev->dev, "pinmux ops lacks necessary functions\n");
44 		return -EINVAL;
45 	}
46 	/* Check that all functions registered have names */
47 	nfuncs = ops->get_functions_count(pctldev);
48 	while (selector < nfuncs) {
49 		const char *fname = ops->get_function_name(pctldev,
50 							   selector);
51 		if (!fname) {
52 			dev_err(pctldev->dev, "pinmux ops has no name for function%u\n",
53 				selector);
54 			return -EINVAL;
55 		}
56 		selector++;
57 	}
58 
59 	return 0;
60 }
61 
62 int pinmux_validate_map(const struct pinctrl_map *map, int i)
63 {
64 	if (!map->data.mux.function) {
65 		pr_err("failed to register map %s (%d): no function given\n",
66 		       map->name, i);
67 		return -EINVAL;
68 	}
69 
70 	return 0;
71 }
72 
73 /**
74  * pinmux_can_be_used_for_gpio() - check if a specific pin
75  *	is either muxed to a different function or used as gpio.
76  *
77  * @pin: the pin number in the global pin space
78  *
79  * Controllers not defined as strict will always return true,
80  * menaning that the gpio can be used.
81  */
82 bool pinmux_can_be_used_for_gpio(struct pinctrl_dev *pctldev, unsigned pin)
83 {
84 	struct pin_desc *desc = pin_desc_get(pctldev, pin);
85 	const struct pinmux_ops *ops = pctldev->desc->pmxops;
86 
87 	/* Can't inspect pin, assume it can be used */
88 	if (!desc)
89 		return true;
90 
91 	if (ops->strict && desc->mux_usecount)
92 		return false;
93 
94 	return !(ops->strict && !!desc->gpio_owner);
95 }
96 
97 /**
98  * pin_request() - request a single pin to be muxed in, typically for GPIO
99  * @pin: the pin number in the global pin space
100  * @owner: a representation of the owner of this pin; typically the device
101  *	name that controls its mux function, or the requested GPIO name
102  * @gpio_range: the range matching the GPIO pin if this is a request for a
103  *	single GPIO pin
104  */
105 static int pin_request(struct pinctrl_dev *pctldev,
106 		       int pin, const char *owner,
107 		       struct pinctrl_gpio_range *gpio_range)
108 {
109 	struct pin_desc *desc;
110 	const struct pinmux_ops *ops = pctldev->desc->pmxops;
111 	int status = -EINVAL;
112 
113 	desc = pin_desc_get(pctldev, pin);
114 	if (desc == NULL) {
115 		dev_err(pctldev->dev,
116 			"pin %d is not registered so it cannot be requested\n",
117 			pin);
118 		goto out;
119 	}
120 
121 	dev_dbg(pctldev->dev, "request pin %d (%s) for %s\n",
122 		pin, desc->name, owner);
123 
124 	if ((!gpio_range || ops->strict) &&
125 	    desc->mux_usecount && strcmp(desc->mux_owner, owner)) {
126 		dev_err(pctldev->dev,
127 			"pin %s already requested by %s; cannot claim for %s\n",
128 			desc->name, desc->mux_owner, owner);
129 		goto out;
130 	}
131 
132 	if ((gpio_range || ops->strict) && desc->gpio_owner) {
133 		dev_err(pctldev->dev,
134 			"pin %s already requested by %s; cannot claim for %s\n",
135 			desc->name, desc->gpio_owner, owner);
136 		goto out;
137 	}
138 
139 	if (gpio_range) {
140 		desc->gpio_owner = owner;
141 	} else {
142 		desc->mux_usecount++;
143 		if (desc->mux_usecount > 1)
144 			return 0;
145 
146 		desc->mux_owner = owner;
147 	}
148 
149 	/* Let each pin increase references to this module */
150 	if (!try_module_get(pctldev->owner)) {
151 		dev_err(pctldev->dev,
152 			"could not increase module refcount for pin %d\n",
153 			pin);
154 		status = -EINVAL;
155 		goto out_free_pin;
156 	}
157 
158 	/*
159 	 * If there is no kind of request function for the pin we just assume
160 	 * we got it by default and proceed.
161 	 */
162 	if (gpio_range && ops->gpio_request_enable)
163 		/* This requests and enables a single GPIO pin */
164 		status = ops->gpio_request_enable(pctldev, gpio_range, pin);
165 	else if (ops->request)
166 		status = ops->request(pctldev, pin);
167 	else
168 		status = 0;
169 
170 	if (status) {
171 		dev_err(pctldev->dev, "request() failed for pin %d\n", pin);
172 		module_put(pctldev->owner);
173 	}
174 
175 out_free_pin:
176 	if (status) {
177 		if (gpio_range) {
178 			desc->gpio_owner = NULL;
179 		} else {
180 			desc->mux_usecount--;
181 			if (!desc->mux_usecount)
182 				desc->mux_owner = NULL;
183 		}
184 	}
185 out:
186 	if (status)
187 		dev_err(pctldev->dev, "pin-%d (%s) status %d\n",
188 			pin, owner, status);
189 
190 	return status;
191 }
192 
193 /**
194  * pin_free() - release a single muxed in pin so something else can be muxed
195  * @pctldev: pin controller device handling this pin
196  * @pin: the pin to free
197  * @gpio_range: the range matching the GPIO pin if this is a request for a
198  *	single GPIO pin
199  *
200  * This function returns a pointer to the previous owner. This is used
201  * for callers that dynamically allocate an owner name so it can be freed
202  * once the pin is free. This is done for GPIO request functions.
203  */
204 static const char *pin_free(struct pinctrl_dev *pctldev, int pin,
205 			    struct pinctrl_gpio_range *gpio_range)
206 {
207 	const struct pinmux_ops *ops = pctldev->desc->pmxops;
208 	struct pin_desc *desc;
209 	const char *owner;
210 
211 	desc = pin_desc_get(pctldev, pin);
212 	if (desc == NULL) {
213 		dev_err(pctldev->dev,
214 			"pin is not registered so it cannot be freed\n");
215 		return NULL;
216 	}
217 
218 	if (!gpio_range) {
219 		/*
220 		 * A pin should not be freed more times than allocated.
221 		 */
222 		if (WARN_ON(!desc->mux_usecount))
223 			return NULL;
224 		desc->mux_usecount--;
225 		if (desc->mux_usecount)
226 			return NULL;
227 	}
228 
229 	/*
230 	 * If there is no kind of request function for the pin we just assume
231 	 * we got it by default and proceed.
232 	 */
233 	if (gpio_range && ops->gpio_disable_free)
234 		ops->gpio_disable_free(pctldev, gpio_range, pin);
235 	else if (ops->free)
236 		ops->free(pctldev, pin);
237 
238 	if (gpio_range) {
239 		owner = desc->gpio_owner;
240 		desc->gpio_owner = NULL;
241 	} else {
242 		owner = desc->mux_owner;
243 		desc->mux_owner = NULL;
244 		desc->mux_setting = NULL;
245 	}
246 
247 	module_put(pctldev->owner);
248 
249 	return owner;
250 }
251 
252 /**
253  * pinmux_request_gpio() - request pinmuxing for a GPIO pin
254  * @pctldev: pin controller device affected
255  * @pin: the pin to mux in for GPIO
256  * @range: the applicable GPIO range
257  */
258 int pinmux_request_gpio(struct pinctrl_dev *pctldev,
259 			struct pinctrl_gpio_range *range,
260 			unsigned pin, unsigned gpio)
261 {
262 	const char *owner;
263 	int ret;
264 
265 	/* Conjure some name stating what chip and pin this is taken by */
266 	owner = kasprintf(GFP_KERNEL, "%s:%d", range->name, gpio);
267 	if (!owner)
268 		return -ENOMEM;
269 
270 	ret = pin_request(pctldev, pin, owner, range);
271 	if (ret < 0)
272 		kfree(owner);
273 
274 	return ret;
275 }
276 
277 /**
278  * pinmux_free_gpio() - release a pin from GPIO muxing
279  * @pctldev: the pin controller device for the pin
280  * @pin: the affected currently GPIO-muxed in pin
281  * @range: applicable GPIO range
282  */
283 void pinmux_free_gpio(struct pinctrl_dev *pctldev, unsigned pin,
284 		      struct pinctrl_gpio_range *range)
285 {
286 	const char *owner;
287 
288 	owner = pin_free(pctldev, pin, range);
289 	kfree(owner);
290 }
291 
292 /**
293  * pinmux_gpio_direction() - set the direction of a single muxed-in GPIO pin
294  * @pctldev: the pin controller handling this pin
295  * @range: applicable GPIO range
296  * @pin: the affected GPIO pin in this controller
297  * @input: true if we set the pin as input, false for output
298  */
299 int pinmux_gpio_direction(struct pinctrl_dev *pctldev,
300 			  struct pinctrl_gpio_range *range,
301 			  unsigned pin, bool input)
302 {
303 	const struct pinmux_ops *ops;
304 	int ret;
305 
306 	ops = pctldev->desc->pmxops;
307 
308 	if (ops->gpio_set_direction)
309 		ret = ops->gpio_set_direction(pctldev, range, pin, input);
310 	else
311 		ret = 0;
312 
313 	return ret;
314 }
315 
316 static int pinmux_func_name_to_selector(struct pinctrl_dev *pctldev,
317 					const char *function)
318 {
319 	const struct pinmux_ops *ops = pctldev->desc->pmxops;
320 	unsigned nfuncs = ops->get_functions_count(pctldev);
321 	unsigned selector = 0;
322 
323 	/* See if this pctldev has this function */
324 	while (selector < nfuncs) {
325 		const char *fname = ops->get_function_name(pctldev, selector);
326 
327 		if (!strcmp(function, fname))
328 			return selector;
329 
330 		selector++;
331 	}
332 
333 	return -EINVAL;
334 }
335 
336 int pinmux_map_to_setting(const struct pinctrl_map *map,
337 			  struct pinctrl_setting *setting)
338 {
339 	struct pinctrl_dev *pctldev = setting->pctldev;
340 	const struct pinmux_ops *pmxops = pctldev->desc->pmxops;
341 	char const * const *groups;
342 	unsigned num_groups;
343 	int ret;
344 	const char *group;
345 
346 	if (!pmxops) {
347 		dev_err(pctldev->dev, "does not support mux function\n");
348 		return -EINVAL;
349 	}
350 
351 	ret = pinmux_func_name_to_selector(pctldev, map->data.mux.function);
352 	if (ret < 0) {
353 		dev_err(pctldev->dev, "invalid function %s in map table\n",
354 			map->data.mux.function);
355 		return ret;
356 	}
357 	setting->data.mux.func = ret;
358 
359 	ret = pmxops->get_function_groups(pctldev, setting->data.mux.func,
360 					  &groups, &num_groups);
361 	if (ret < 0) {
362 		dev_err(pctldev->dev, "can't query groups for function %s\n",
363 			map->data.mux.function);
364 		return ret;
365 	}
366 	if (!num_groups) {
367 		dev_err(pctldev->dev,
368 			"function %s can't be selected on any group\n",
369 			map->data.mux.function);
370 		return -EINVAL;
371 	}
372 	if (map->data.mux.group) {
373 		group = map->data.mux.group;
374 		ret = match_string(groups, num_groups, group);
375 		if (ret < 0) {
376 			dev_err(pctldev->dev,
377 				"invalid group \"%s\" for function \"%s\"\n",
378 				group, map->data.mux.function);
379 			return ret;
380 		}
381 	} else {
382 		group = groups[0];
383 	}
384 
385 	ret = pinctrl_get_group_selector(pctldev, group);
386 	if (ret < 0) {
387 		dev_err(pctldev->dev, "invalid group %s in map table\n",
388 			map->data.mux.group);
389 		return ret;
390 	}
391 	setting->data.mux.group = ret;
392 
393 	return 0;
394 }
395 
396 void pinmux_free_setting(const struct pinctrl_setting *setting)
397 {
398 	/* This function is currently unused */
399 }
400 
401 int pinmux_enable_setting(const struct pinctrl_setting *setting)
402 {
403 	struct pinctrl_dev *pctldev = setting->pctldev;
404 	const struct pinctrl_ops *pctlops = pctldev->desc->pctlops;
405 	const struct pinmux_ops *ops = pctldev->desc->pmxops;
406 	int ret = 0;
407 	const unsigned *pins = NULL;
408 	unsigned num_pins = 0;
409 	int i;
410 	struct pin_desc *desc;
411 
412 	if (pctlops->get_group_pins)
413 		ret = pctlops->get_group_pins(pctldev, setting->data.mux.group,
414 					      &pins, &num_pins);
415 
416 	if (ret) {
417 		const char *gname;
418 
419 		/* errors only affect debug data, so just warn */
420 		gname = pctlops->get_group_name(pctldev,
421 						setting->data.mux.group);
422 		dev_warn(pctldev->dev,
423 			 "could not get pins for group %s\n",
424 			 gname);
425 		num_pins = 0;
426 	}
427 
428 	/* Try to allocate all pins in this group, one by one */
429 	for (i = 0; i < num_pins; i++) {
430 		ret = pin_request(pctldev, pins[i], setting->dev_name, NULL);
431 		if (ret) {
432 			const char *gname;
433 			const char *pname;
434 
435 			desc = pin_desc_get(pctldev, pins[i]);
436 			pname = desc ? desc->name : "non-existing";
437 			gname = pctlops->get_group_name(pctldev,
438 						setting->data.mux.group);
439 			dev_err(pctldev->dev,
440 				"could not request pin %d (%s) from group %s "
441 				" on device %s\n",
442 				pins[i], pname, gname,
443 				pinctrl_dev_get_name(pctldev));
444 			goto err_pin_request;
445 		}
446 	}
447 
448 	/* Now that we have acquired the pins, encode the mux setting */
449 	for (i = 0; i < num_pins; i++) {
450 		desc = pin_desc_get(pctldev, pins[i]);
451 		if (desc == NULL) {
452 			dev_warn(pctldev->dev,
453 				 "could not get pin desc for pin %d\n",
454 				 pins[i]);
455 			continue;
456 		}
457 		desc->mux_setting = &(setting->data.mux);
458 	}
459 
460 	ret = ops->set_mux(pctldev, setting->data.mux.func,
461 			   setting->data.mux.group);
462 
463 	if (ret)
464 		goto err_set_mux;
465 
466 	return 0;
467 
468 err_set_mux:
469 	for (i = 0; i < num_pins; i++) {
470 		desc = pin_desc_get(pctldev, pins[i]);
471 		if (desc)
472 			desc->mux_setting = NULL;
473 	}
474 err_pin_request:
475 	/* On error release all taken pins */
476 	while (--i >= 0)
477 		pin_free(pctldev, pins[i], NULL);
478 
479 	return ret;
480 }
481 
482 void pinmux_disable_setting(const struct pinctrl_setting *setting)
483 {
484 	struct pinctrl_dev *pctldev = setting->pctldev;
485 	const struct pinctrl_ops *pctlops = pctldev->desc->pctlops;
486 	int ret = 0;
487 	const unsigned *pins = NULL;
488 	unsigned num_pins = 0;
489 	int i;
490 	struct pin_desc *desc;
491 
492 	if (pctlops->get_group_pins)
493 		ret = pctlops->get_group_pins(pctldev, setting->data.mux.group,
494 					      &pins, &num_pins);
495 	if (ret) {
496 		const char *gname;
497 
498 		/* errors only affect debug data, so just warn */
499 		gname = pctlops->get_group_name(pctldev,
500 						setting->data.mux.group);
501 		dev_warn(pctldev->dev,
502 			 "could not get pins for group %s\n",
503 			 gname);
504 		num_pins = 0;
505 	}
506 
507 	/* Flag the descs that no setting is active */
508 	for (i = 0; i < num_pins; i++) {
509 		desc = pin_desc_get(pctldev, pins[i]);
510 		if (desc == NULL) {
511 			dev_warn(pctldev->dev,
512 				 "could not get pin desc for pin %d\n",
513 				 pins[i]);
514 			continue;
515 		}
516 		if (desc->mux_setting == &(setting->data.mux)) {
517 			pin_free(pctldev, pins[i], NULL);
518 		} else {
519 			const char *gname;
520 
521 			gname = pctlops->get_group_name(pctldev,
522 						setting->data.mux.group);
523 			dev_warn(pctldev->dev,
524 				 "not freeing pin %d (%s) as part of "
525 				 "deactivating group %s - it is already "
526 				 "used for some other setting",
527 				 pins[i], desc->name, gname);
528 		}
529 	}
530 }
531 
532 #ifdef CONFIG_DEBUG_FS
533 
534 /* Called from pincontrol core */
535 static int pinmux_functions_show(struct seq_file *s, void *what)
536 {
537 	struct pinctrl_dev *pctldev = s->private;
538 	const struct pinmux_ops *pmxops = pctldev->desc->pmxops;
539 	unsigned nfuncs;
540 	unsigned func_selector = 0;
541 
542 	if (!pmxops)
543 		return 0;
544 
545 	mutex_lock(&pctldev->mutex);
546 	nfuncs = pmxops->get_functions_count(pctldev);
547 	while (func_selector < nfuncs) {
548 		const char *func = pmxops->get_function_name(pctldev,
549 							  func_selector);
550 		const char * const *groups;
551 		unsigned num_groups;
552 		int ret;
553 		int i;
554 
555 		ret = pmxops->get_function_groups(pctldev, func_selector,
556 						  &groups, &num_groups);
557 		if (ret) {
558 			seq_printf(s, "function %s: COULD NOT GET GROUPS\n",
559 				   func);
560 			func_selector++;
561 			continue;
562 		}
563 
564 		seq_printf(s, "function: %s, groups = [ ", func);
565 		for (i = 0; i < num_groups; i++)
566 			seq_printf(s, "%s ", groups[i]);
567 		seq_puts(s, "]\n");
568 
569 		func_selector++;
570 	}
571 
572 	mutex_unlock(&pctldev->mutex);
573 
574 	return 0;
575 }
576 
577 static int pinmux_pins_show(struct seq_file *s, void *what)
578 {
579 	struct pinctrl_dev *pctldev = s->private;
580 	const struct pinctrl_ops *pctlops = pctldev->desc->pctlops;
581 	const struct pinmux_ops *pmxops = pctldev->desc->pmxops;
582 	unsigned i, pin;
583 
584 	if (!pmxops)
585 		return 0;
586 
587 	seq_puts(s, "Pinmux settings per pin\n");
588 	if (pmxops->strict)
589 		seq_puts(s,
590 		 "Format: pin (name): mux_owner|gpio_owner (strict) hog?\n");
591 	else
592 		seq_puts(s,
593 		"Format: pin (name): mux_owner gpio_owner hog?\n");
594 
595 	mutex_lock(&pctldev->mutex);
596 
597 	/* The pin number can be retrived from the pin controller descriptor */
598 	for (i = 0; i < pctldev->desc->npins; i++) {
599 		struct pin_desc *desc;
600 		bool is_hog = false;
601 
602 		pin = pctldev->desc->pins[i].number;
603 		desc = pin_desc_get(pctldev, pin);
604 		/* Skip if we cannot search the pin */
605 		if (desc == NULL)
606 			continue;
607 
608 		if (desc->mux_owner &&
609 		    !strcmp(desc->mux_owner, pinctrl_dev_get_name(pctldev)))
610 			is_hog = true;
611 
612 		if (pmxops->strict) {
613 			if (desc->mux_owner)
614 				seq_printf(s, "pin %d (%s): device %s%s",
615 					   pin, desc->name, desc->mux_owner,
616 					   is_hog ? " (HOG)" : "");
617 			else if (desc->gpio_owner)
618 				seq_printf(s, "pin %d (%s): GPIO %s",
619 					   pin, desc->name, desc->gpio_owner);
620 			else
621 				seq_printf(s, "pin %d (%s): UNCLAIMED",
622 					   pin, desc->name);
623 		} else {
624 			/* For non-strict controllers */
625 			seq_printf(s, "pin %d (%s): %s %s%s", pin, desc->name,
626 				   desc->mux_owner ? desc->mux_owner
627 				   : "(MUX UNCLAIMED)",
628 				   desc->gpio_owner ? desc->gpio_owner
629 				   : "(GPIO UNCLAIMED)",
630 				   is_hog ? " (HOG)" : "");
631 		}
632 
633 		/* If mux: print function+group claiming the pin */
634 		if (desc->mux_setting)
635 			seq_printf(s, " function %s group %s\n",
636 				   pmxops->get_function_name(pctldev,
637 					desc->mux_setting->func),
638 				   pctlops->get_group_name(pctldev,
639 					desc->mux_setting->group));
640 		else
641 			seq_putc(s, '\n');
642 	}
643 
644 	mutex_unlock(&pctldev->mutex);
645 
646 	return 0;
647 }
648 
649 void pinmux_show_map(struct seq_file *s, const struct pinctrl_map *map)
650 {
651 	seq_printf(s, "group %s\nfunction %s\n",
652 		map->data.mux.group ? map->data.mux.group : "(default)",
653 		map->data.mux.function);
654 }
655 
656 void pinmux_show_setting(struct seq_file *s,
657 			 const struct pinctrl_setting *setting)
658 {
659 	struct pinctrl_dev *pctldev = setting->pctldev;
660 	const struct pinmux_ops *pmxops = pctldev->desc->pmxops;
661 	const struct pinctrl_ops *pctlops = pctldev->desc->pctlops;
662 
663 	seq_printf(s, "group: %s (%u) function: %s (%u)\n",
664 		   pctlops->get_group_name(pctldev, setting->data.mux.group),
665 		   setting->data.mux.group,
666 		   pmxops->get_function_name(pctldev, setting->data.mux.func),
667 		   setting->data.mux.func);
668 }
669 
670 DEFINE_SHOW_ATTRIBUTE(pinmux_functions);
671 DEFINE_SHOW_ATTRIBUTE(pinmux_pins);
672 
673 void pinmux_init_device_debugfs(struct dentry *devroot,
674 			 struct pinctrl_dev *pctldev)
675 {
676 	debugfs_create_file("pinmux-functions", S_IFREG | S_IRUGO,
677 			    devroot, pctldev, &pinmux_functions_fops);
678 	debugfs_create_file("pinmux-pins", S_IFREG | S_IRUGO,
679 			    devroot, pctldev, &pinmux_pins_fops);
680 }
681 
682 #endif /* CONFIG_DEBUG_FS */
683 
684 #ifdef CONFIG_GENERIC_PINMUX_FUNCTIONS
685 
686 /**
687  * pinmux_generic_get_function_count() - returns number of functions
688  * @pctldev: pin controller device
689  */
690 int pinmux_generic_get_function_count(struct pinctrl_dev *pctldev)
691 {
692 	return pctldev->num_functions;
693 }
694 EXPORT_SYMBOL_GPL(pinmux_generic_get_function_count);
695 
696 /**
697  * pinmux_generic_get_function_name() - returns the function name
698  * @pctldev: pin controller device
699  * @selector: function number
700  */
701 const char *
702 pinmux_generic_get_function_name(struct pinctrl_dev *pctldev,
703 				 unsigned int selector)
704 {
705 	struct function_desc *function;
706 
707 	function = radix_tree_lookup(&pctldev->pin_function_tree,
708 				     selector);
709 	if (!function)
710 		return NULL;
711 
712 	return function->name;
713 }
714 EXPORT_SYMBOL_GPL(pinmux_generic_get_function_name);
715 
716 /**
717  * pinmux_generic_get_function_groups() - gets the function groups
718  * @pctldev: pin controller device
719  * @selector: function number
720  * @groups: array of pin groups
721  * @num_groups: number of pin groups
722  */
723 int pinmux_generic_get_function_groups(struct pinctrl_dev *pctldev,
724 				       unsigned int selector,
725 				       const char * const **groups,
726 				       unsigned * const num_groups)
727 {
728 	struct function_desc *function;
729 
730 	function = radix_tree_lookup(&pctldev->pin_function_tree,
731 				     selector);
732 	if (!function) {
733 		dev_err(pctldev->dev, "%s could not find function%i\n",
734 			__func__, selector);
735 		return -EINVAL;
736 	}
737 	*groups = function->group_names;
738 	*num_groups = function->num_group_names;
739 
740 	return 0;
741 }
742 EXPORT_SYMBOL_GPL(pinmux_generic_get_function_groups);
743 
744 /**
745  * pinmux_generic_get_function() - returns a function based on the number
746  * @pctldev: pin controller device
747  * @group_selector: function number
748  */
749 struct function_desc *pinmux_generic_get_function(struct pinctrl_dev *pctldev,
750 						  unsigned int selector)
751 {
752 	struct function_desc *function;
753 
754 	function = radix_tree_lookup(&pctldev->pin_function_tree,
755 				     selector);
756 	if (!function)
757 		return NULL;
758 
759 	return function;
760 }
761 EXPORT_SYMBOL_GPL(pinmux_generic_get_function);
762 
763 /**
764  * pinmux_generic_add_function() - adds a function group
765  * @pctldev: pin controller device
766  * @name: name of the function
767  * @groups: array of pin groups
768  * @num_groups: number of pin groups
769  * @data: pin controller driver specific data
770  */
771 int pinmux_generic_add_function(struct pinctrl_dev *pctldev,
772 				const char *name,
773 				const char **groups,
774 				const unsigned int num_groups,
775 				void *data)
776 {
777 	struct function_desc *function;
778 	int selector;
779 
780 	if (!name)
781 		return -EINVAL;
782 
783 	selector = pinmux_func_name_to_selector(pctldev, name);
784 	if (selector >= 0)
785 		return selector;
786 
787 	selector = pctldev->num_functions;
788 
789 	function = devm_kzalloc(pctldev->dev, sizeof(*function), GFP_KERNEL);
790 	if (!function)
791 		return -ENOMEM;
792 
793 	function->name = name;
794 	function->group_names = groups;
795 	function->num_group_names = num_groups;
796 	function->data = data;
797 
798 	radix_tree_insert(&pctldev->pin_function_tree, selector, function);
799 
800 	pctldev->num_functions++;
801 
802 	return selector;
803 }
804 EXPORT_SYMBOL_GPL(pinmux_generic_add_function);
805 
806 /**
807  * pinmux_generic_remove_function() - removes a numbered function
808  * @pctldev: pin controller device
809  * @selector: function number
810  *
811  * Note that the caller must take care of locking.
812  */
813 int pinmux_generic_remove_function(struct pinctrl_dev *pctldev,
814 				   unsigned int selector)
815 {
816 	struct function_desc *function;
817 
818 	function = radix_tree_lookup(&pctldev->pin_function_tree,
819 				     selector);
820 	if (!function)
821 		return -ENOENT;
822 
823 	radix_tree_delete(&pctldev->pin_function_tree, selector);
824 	devm_kfree(pctldev->dev, function);
825 
826 	pctldev->num_functions--;
827 
828 	return 0;
829 }
830 EXPORT_SYMBOL_GPL(pinmux_generic_remove_function);
831 
832 /**
833  * pinmux_generic_free_functions() - removes all functions
834  * @pctldev: pin controller device
835  *
836  * Note that the caller must take care of locking. The pinctrl
837  * functions are allocated with devm_kzalloc() so no need to free
838  * them here.
839  */
840 void pinmux_generic_free_functions(struct pinctrl_dev *pctldev)
841 {
842 	struct radix_tree_iter iter;
843 	void __rcu **slot;
844 
845 	radix_tree_for_each_slot(slot, &pctldev->pin_function_tree, &iter, 0)
846 		radix_tree_delete(&pctldev->pin_function_tree, iter.index);
847 
848 	pctldev->num_functions = 0;
849 }
850 
851 #endif /* CONFIG_GENERIC_PINMUX_FUNCTIONS */
852