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1 /*
2 * Core driver for the pin muxing portions of the pin control subsystem
3 *
4 * Copyright (C) 2011-2012 ST-Ericsson SA
5 * Written on behalf of Linaro for ST-Ericsson
6 * Based on bits of regulator core, gpio core and clk core
7 *
8 * Author: Linus Walleij <linus.walleij@linaro.org>
9 *
10 * Copyright (C) 2012 NVIDIA CORPORATION. All rights reserved.
11 *
12 * License terms: GNU General Public License (GPL) version 2
13 */
14 #define pr_fmt(fmt) "pinmux core: " fmt
15
16 #include <linux/kernel.h>
17 #include <linux/module.h>
18 #include <linux/init.h>
19 #include <linux/device.h>
20 #include <linux/slab.h>
21 #include <linux/radix-tree.h>
22 #include <linux/err.h>
23 #include <linux/list.h>
24 #include <linux/string.h>
25 #include <linux/sysfs.h>
26 #include <linux/debugfs.h>
27 #include <linux/seq_file.h>
28 #include <linux/pinctrl/machine.h>
29 #include <linux/pinctrl/pinmux.h>
30 #include "core.h"
31 #include "pinmux.h"
32
33 int pinmux_check_ops(struct pinctrl_dev *pctldev)
34 {
35 const struct pinmux_ops *ops = pctldev->desc->pmxops;
36 unsigned nfuncs;
37 unsigned selector = 0;
38
39 /* Check that we implement required operations */
40 if (!ops ||
41 !ops->get_functions_count ||
42 !ops->get_function_name ||
43 !ops->get_function_groups ||
44 !ops->set_mux) {
45 dev_err(pctldev->dev, "pinmux ops lacks necessary functions\n");
46 return -EINVAL;
47 }
48 /* Check that all functions registered have names */
49 nfuncs = ops->get_functions_count(pctldev);
50 while (selector < nfuncs) {
51 const char *fname = ops->get_function_name(pctldev,
52 selector);
53 if (!fname) {
54 dev_err(pctldev->dev, "pinmux ops has no name for function%u\n",
55 selector);
56 return -EINVAL;
57 }
58 selector++;
59 }
60
61 return 0;
62 }
63
64 int pinmux_validate_map(struct pinctrl_map const *map, int i)
65 {
66 if (!map->data.mux.function) {
67 pr_err("failed to register map %s (%d): no function given\n",
68 map->name, i);
69 return -EINVAL;
70 }
71
72 return 0;
73 }
74
75 /**
76 * pin_request() - request a single pin to be muxed in, typically for GPIO
77 * @pin: the pin number in the global pin space
78 * @owner: a representation of the owner of this pin; typically the device
79 * name that controls its mux function, or the requested GPIO name
80 * @gpio_range: the range matching the GPIO pin if this is a request for a
81 * single GPIO pin
82 */
83 static int pin_request(struct pinctrl_dev *pctldev,
84 int pin, const char *owner,
85 struct pinctrl_gpio_range *gpio_range)
86 {
87 struct pin_desc *desc;
88 const struct pinmux_ops *ops = pctldev->desc->pmxops;
89 int status = -EINVAL;
90
91 desc = pin_desc_get(pctldev, pin);
92 if (desc == NULL) {
93 dev_err(pctldev->dev,
94 "pin %d is not registered so it cannot be requested\n",
95 pin);
96 goto out;
97 }
98
99 dev_dbg(pctldev->dev, "request pin %d (%s) for %s\n",
100 pin, desc->name, owner);
101
102 if (gpio_range) {
103 /* There's no need to support multiple GPIO requests */
104 if (desc->gpio_owner) {
105 dev_err(pctldev->dev,
106 "pin %s already requested by %s; cannot claim for %s\n",
107 desc->name, desc->gpio_owner, owner);
108 goto out;
109 }
110 if (ops->strict && desc->mux_usecount &&
111 strcmp(desc->mux_owner, owner)) {
112 dev_err(pctldev->dev,
113 "pin %s already requested by %s; cannot claim for %s\n",
114 desc->name, desc->mux_owner, owner);
115 goto out;
116 }
117
118 desc->gpio_owner = owner;
119 } else {
120 if (desc->mux_usecount && strcmp(desc->mux_owner, owner)) {
121 dev_err(pctldev->dev,
122 "pin %s already requested by %s; cannot claim for %s\n",
123 desc->name, desc->mux_owner, owner);
124 goto out;
125 }
126 if (ops->strict && desc->gpio_owner) {
127 dev_err(pctldev->dev,
128 "pin %s already requested by %s; cannot claim for %s\n",
129 desc->name, desc->gpio_owner, owner);
130 goto out;
131 }
132
133 desc->mux_usecount++;
134 if (desc->mux_usecount > 1)
135 return 0;
136
137 desc->mux_owner = owner;
138 }
139
140 /* Let each pin increase references to this module */
141 if (!try_module_get(pctldev->owner)) {
142 dev_err(pctldev->dev,
143 "could not increase module refcount for pin %d\n",
144 pin);
145 status = -EINVAL;
146 goto out_free_pin;
147 }
148
149 /*
150 * If there is no kind of request function for the pin we just assume
151 * we got it by default and proceed.
152 */
153 if (gpio_range && ops->gpio_request_enable)
154 /* This requests and enables a single GPIO pin */
155 status = ops->gpio_request_enable(pctldev, gpio_range, pin);
156 else if (ops->request)
157 status = ops->request(pctldev, pin);
158 else
159 status = 0;
160
161 if (status) {
162 dev_err(pctldev->dev, "request() failed for pin %d\n", pin);
163 module_put(pctldev->owner);
164 }
165
166 out_free_pin:
167 if (status) {
168 if (gpio_range) {
169 desc->gpio_owner = NULL;
170 } else {
171 desc->mux_usecount--;
172 if (!desc->mux_usecount)
173 desc->mux_owner = NULL;
174 }
175 }
176 out:
177 if (status)
178 dev_err(pctldev->dev, "pin-%d (%s) status %d\n",
179 pin, owner, status);
180
181 return status;
182 }
183
184 /**
185 * pin_free() - release a single muxed in pin so something else can be muxed
186 * @pctldev: pin controller device handling this pin
187 * @pin: the pin to free
188 * @gpio_range: the range matching the GPIO pin if this is a request for a
189 * single GPIO pin
190 *
191 * This function returns a pointer to the previous owner. This is used
192 * for callers that dynamically allocate an owner name so it can be freed
193 * once the pin is free. This is done for GPIO request functions.
194 */
195 static const char *pin_free(struct pinctrl_dev *pctldev, int pin,
196 struct pinctrl_gpio_range *gpio_range)
197 {
198 const struct pinmux_ops *ops = pctldev->desc->pmxops;
199 struct pin_desc *desc;
200 const char *owner;
201
202 desc = pin_desc_get(pctldev, pin);
203 if (desc == NULL) {
204 dev_err(pctldev->dev,
205 "pin is not registered so it cannot be freed\n");
206 return NULL;
207 }
208
209 if (!gpio_range) {
210 /*
211 * A pin should not be freed more times than allocated.
212 */
213 if (WARN_ON(!desc->mux_usecount))
214 return NULL;
215 desc->mux_usecount--;
216 if (desc->mux_usecount)
217 return NULL;
218 }
219
220 /*
221 * If there is no kind of request function for the pin we just assume
222 * we got it by default and proceed.
223 */
224 if (gpio_range && ops->gpio_disable_free)
225 ops->gpio_disable_free(pctldev, gpio_range, pin);
226 else if (ops->free)
227 ops->free(pctldev, pin);
228
229 if (gpio_range) {
230 owner = desc->gpio_owner;
231 desc->gpio_owner = NULL;
232 } else {
233 owner = desc->mux_owner;
234 desc->mux_owner = NULL;
235 desc->mux_setting = NULL;
236 }
237
238 module_put(pctldev->owner);
239
240 return owner;
241 }
242
243 /**
244 * pinmux_request_gpio() - request pinmuxing for a GPIO pin
245 * @pctldev: pin controller device affected
246 * @pin: the pin to mux in for GPIO
247 * @range: the applicable GPIO range
248 */
249 int pinmux_request_gpio(struct pinctrl_dev *pctldev,
250 struct pinctrl_gpio_range *range,
251 unsigned pin, unsigned gpio)
252 {
253 const char *owner;
254 int ret;
255
256 /* Conjure some name stating what chip and pin this is taken by */
257 owner = kasprintf(GFP_KERNEL, "%s:%d", range->name, gpio);
258 if (!owner)
259 return -EINVAL;
260
261 ret = pin_request(pctldev, pin, owner, range);
262 if (ret < 0)
263 kfree(owner);
264
265 return ret;
266 }
267
268 /**
269 * pinmux_free_gpio() - release a pin from GPIO muxing
270 * @pctldev: the pin controller device for the pin
271 * @pin: the affected currently GPIO-muxed in pin
272 * @range: applicable GPIO range
273 */
274 void pinmux_free_gpio(struct pinctrl_dev *pctldev, unsigned pin,
275 struct pinctrl_gpio_range *range)
276 {
277 const char *owner;
278
279 owner = pin_free(pctldev, pin, range);
280 kfree(owner);
281 }
282
283 /**
284 * pinmux_gpio_direction() - set the direction of a single muxed-in GPIO pin
285 * @pctldev: the pin controller handling this pin
286 * @range: applicable GPIO range
287 * @pin: the affected GPIO pin in this controller
288 * @input: true if we set the pin as input, false for output
289 */
290 int pinmux_gpio_direction(struct pinctrl_dev *pctldev,
291 struct pinctrl_gpio_range *range,
292 unsigned pin, bool input)
293 {
294 const struct pinmux_ops *ops;
295 int ret;
296
297 ops = pctldev->desc->pmxops;
298
299 if (ops->gpio_set_direction)
300 ret = ops->gpio_set_direction(pctldev, range, pin, input);
301 else
302 ret = 0;
303
304 return ret;
305 }
306
307 static int pinmux_func_name_to_selector(struct pinctrl_dev *pctldev,
308 const char *function)
309 {
310 const struct pinmux_ops *ops = pctldev->desc->pmxops;
311 unsigned nfuncs = ops->get_functions_count(pctldev);
312 unsigned selector = 0;
313
314 /* See if this pctldev has this function */
315 while (selector < nfuncs) {
316 const char *fname = ops->get_function_name(pctldev,
317 selector);
318
319 if (!strcmp(function, fname))
320 return selector;
321
322 selector++;
323 }
324
325 dev_err(pctldev->dev, "function '%s' not supported\n", function);
326 return -EINVAL;
327 }
328
329 int pinmux_map_to_setting(struct pinctrl_map const *map,
330 struct pinctrl_setting *setting)
331 {
332 struct pinctrl_dev *pctldev = setting->pctldev;
333 const struct pinmux_ops *pmxops = pctldev->desc->pmxops;
334 char const * const *groups;
335 unsigned num_groups;
336 int ret;
337 const char *group;
338 int i;
339
340 if (!pmxops) {
341 dev_err(pctldev->dev, "does not support mux function\n");
342 return -EINVAL;
343 }
344
345 ret = pinmux_func_name_to_selector(pctldev, map->data.mux.function);
346 if (ret < 0) {
347 dev_err(pctldev->dev, "invalid function %s in map table\n",
348 map->data.mux.function);
349 return ret;
350 }
351 setting->data.mux.func = ret;
352
353 ret = pmxops->get_function_groups(pctldev, setting->data.mux.func,
354 &groups, &num_groups);
355 if (ret < 0) {
356 dev_err(pctldev->dev, "can't query groups for function %s\n",
357 map->data.mux.function);
358 return ret;
359 }
360 if (!num_groups) {
361 dev_err(pctldev->dev,
362 "function %s can't be selected on any group\n",
363 map->data.mux.function);
364 return -EINVAL;
365 }
366 if (map->data.mux.group) {
367 bool found = false;
368 group = map->data.mux.group;
369 for (i = 0; i < num_groups; i++) {
370 if (!strcmp(group, groups[i])) {
371 found = true;
372 break;
373 }
374 }
375 if (!found) {
376 dev_err(pctldev->dev,
377 "invalid group \"%s\" for function \"%s\"\n",
378 group, map->data.mux.function);
379 return -EINVAL;
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(struct pinctrl_setting const *setting)
397 {
398 /* This function is currently unused */
399 }
400
401 int pinmux_enable_setting(struct pinctrl_setting const *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(struct pinctrl_setting const *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 desc->mux_setting = NULL;
518 /* And release the pin */
519 pin_free(pctldev, pins[i], NULL);
520 } else {
521 const char *gname;
522
523 gname = pctlops->get_group_name(pctldev,
524 setting->data.mux.group);
525 dev_warn(pctldev->dev,
526 "not freeing pin %d (%s) as part of "
527 "deactivating group %s - it is already "
528 "used for some other setting",
529 pins[i], desc->name, gname);
530 }
531 }
532 }
533
534 #ifdef CONFIG_DEBUG_FS
535
536 /* Called from pincontrol core */
537 static int pinmux_functions_show(struct seq_file *s, void *what)
538 {
539 struct pinctrl_dev *pctldev = s->private;
540 const struct pinmux_ops *pmxops = pctldev->desc->pmxops;
541 unsigned nfuncs;
542 unsigned func_selector = 0;
543
544 if (!pmxops)
545 return 0;
546
547 mutex_lock(&pctldev->mutex);
548 nfuncs = pmxops->get_functions_count(pctldev);
549 while (func_selector < nfuncs) {
550 const char *func = pmxops->get_function_name(pctldev,
551 func_selector);
552 const char * const *groups;
553 unsigned num_groups;
554 int ret;
555 int i;
556
557 ret = pmxops->get_function_groups(pctldev, func_selector,
558 &groups, &num_groups);
559 if (ret) {
560 seq_printf(s, "function %s: COULD NOT GET GROUPS\n",
561 func);
562 func_selector++;
563 continue;
564 }
565
566 seq_printf(s, "function: %s, groups = [ ", func);
567 for (i = 0; i < num_groups; i++)
568 seq_printf(s, "%s ", groups[i]);
569 seq_puts(s, "]\n");
570
571 func_selector++;
572 }
573
574 mutex_unlock(&pctldev->mutex);
575
576 return 0;
577 }
578
579 static int pinmux_pins_show(struct seq_file *s, void *what)
580 {
581 struct pinctrl_dev *pctldev = s->private;
582 const struct pinctrl_ops *pctlops = pctldev->desc->pctlops;
583 const struct pinmux_ops *pmxops = pctldev->desc->pmxops;
584 unsigned i, pin;
585
586 if (!pmxops)
587 return 0;
588
589 seq_puts(s, "Pinmux settings per pin\n");
590 if (pmxops->strict)
591 seq_puts(s,
592 "Format: pin (name): mux_owner|gpio_owner (strict) hog?\n");
593 else
594 seq_puts(s,
595 "Format: pin (name): mux_owner gpio_owner hog?\n");
596
597 mutex_lock(&pctldev->mutex);
598
599 /* The pin number can be retrived from the pin controller descriptor */
600 for (i = 0; i < pctldev->desc->npins; i++) {
601 struct pin_desc *desc;
602 bool is_hog = false;
603
604 pin = pctldev->desc->pins[i].number;
605 desc = pin_desc_get(pctldev, pin);
606 /* Skip if we cannot search the pin */
607 if (desc == NULL)
608 continue;
609
610 if (desc->mux_owner &&
611 !strcmp(desc->mux_owner, pinctrl_dev_get_name(pctldev)))
612 is_hog = true;
613
614 if (pmxops->strict) {
615 if (desc->mux_owner)
616 seq_printf(s, "pin %d (%s): device %s%s",
617 pin,
618 desc->name ? desc->name : "unnamed",
619 desc->mux_owner,
620 is_hog ? " (HOG)" : "");
621 else if (desc->gpio_owner)
622 seq_printf(s, "pin %d (%s): GPIO %s",
623 pin,
624 desc->name ? desc->name : "unnamed",
625 desc->gpio_owner);
626 else
627 seq_printf(s, "pin %d (%s): UNCLAIMED",
628 pin,
629 desc->name ? desc->name : "unnamed");
630 } else {
631 /* For non-strict controllers */
632 seq_printf(s, "pin %d (%s): %s %s%s", pin,
633 desc->name ? desc->name : "unnamed",
634 desc->mux_owner ? desc->mux_owner
635 : "(MUX UNCLAIMED)",
636 desc->gpio_owner ? desc->gpio_owner
637 : "(GPIO UNCLAIMED)",
638 is_hog ? " (HOG)" : "");
639 }
640
641 /* If mux: print function+group claiming the pin */
642 if (desc->mux_setting)
643 seq_printf(s, " function %s group %s\n",
644 pmxops->get_function_name(pctldev,
645 desc->mux_setting->func),
646 pctlops->get_group_name(pctldev,
647 desc->mux_setting->group));
648 else
649 seq_printf(s, "\n");
650 }
651
652 mutex_unlock(&pctldev->mutex);
653
654 return 0;
655 }
656
657 void pinmux_show_map(struct seq_file *s, struct pinctrl_map const *map)
658 {
659 seq_printf(s, "group %s\nfunction %s\n",
660 map->data.mux.group ? map->data.mux.group : "(default)",
661 map->data.mux.function);
662 }
663
664 void pinmux_show_setting(struct seq_file *s,
665 struct pinctrl_setting const *setting)
666 {
667 struct pinctrl_dev *pctldev = setting->pctldev;
668 const struct pinmux_ops *pmxops = pctldev->desc->pmxops;
669 const struct pinctrl_ops *pctlops = pctldev->desc->pctlops;
670
671 seq_printf(s, "group: %s (%u) function: %s (%u)\n",
672 pctlops->get_group_name(pctldev, setting->data.mux.group),
673 setting->data.mux.group,
674 pmxops->get_function_name(pctldev, setting->data.mux.func),
675 setting->data.mux.func);
676 }
677
678 static int pinmux_functions_open(struct inode *inode, struct file *file)
679 {
680 return single_open(file, pinmux_functions_show, inode->i_private);
681 }
682
683 static int pinmux_pins_open(struct inode *inode, struct file *file)
684 {
685 return single_open(file, pinmux_pins_show, inode->i_private);
686 }
687
688 static const struct file_operations pinmux_functions_ops = {
689 .open = pinmux_functions_open,
690 .read = seq_read,
691 .llseek = seq_lseek,
692 .release = single_release,
693 };
694
695 static const struct file_operations pinmux_pins_ops = {
696 .open = pinmux_pins_open,
697 .read = seq_read,
698 .llseek = seq_lseek,
699 .release = single_release,
700 };
701
702 void pinmux_init_device_debugfs(struct dentry *devroot,
703 struct pinctrl_dev *pctldev)
704 {
705 debugfs_create_file("pinmux-functions", S_IFREG | S_IRUGO,
706 devroot, pctldev, &pinmux_functions_ops);
707 debugfs_create_file("pinmux-pins", S_IFREG | S_IRUGO,
708 devroot, pctldev, &pinmux_pins_ops);
709 }
710
711 #endif /* CONFIG_DEBUG_FS */