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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * GPIO testing driver based on configfs.
4 *
5 * Copyright (C) 2021 Bartosz Golaszewski <brgl@bgdev.pl>
6 */
7
8#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
9
10#include <linux/bitmap.h>
11#include <linux/completion.h>
12#include <linux/configfs.h>
13#include <linux/device.h>
14#include <linux/gpio/driver.h>
15#include <linux/gpio/machine.h>
16#include <linux/idr.h>
17#include <linux/interrupt.h>
18#include <linux/irq.h>
19#include <linux/irq_sim.h>
20#include <linux/list.h>
21#include <linux/mod_devicetable.h>
22#include <linux/module.h>
23#include <linux/mutex.h>
24#include <linux/notifier.h>
25#include <linux/platform_device.h>
26#include <linux/property.h>
27#include <linux/slab.h>
28#include <linux/string.h>
29#include <linux/string_helpers.h>
30#include <linux/sysfs.h>
31
32#include "gpiolib.h"
33
34#define GPIO_SIM_NGPIO_MAX 1024
35#define GPIO_SIM_PROP_MAX 4 /* Max 3 properties + sentinel. */
36#define GPIO_SIM_NUM_ATTRS 3 /* value, pull and sentinel */
37
38static DEFINE_IDA(gpio_sim_ida);
39
40struct gpio_sim_chip {
41 struct gpio_chip gc;
42 unsigned long *direction_map;
43 unsigned long *value_map;
44 unsigned long *pull_map;
45 struct irq_domain *irq_sim;
46 struct mutex lock;
47 const struct attribute_group **attr_groups;
48};
49
50struct gpio_sim_attribute {
51 struct device_attribute dev_attr;
52 unsigned int offset;
53};
54
55static struct gpio_sim_attribute *
56to_gpio_sim_attr(struct device_attribute *dev_attr)
57{
58 return container_of(dev_attr, struct gpio_sim_attribute, dev_attr);
59}
60
61static int gpio_sim_apply_pull(struct gpio_sim_chip *chip,
62 unsigned int offset, int value)
63{
64 int irq, irq_type, ret;
65 struct gpio_desc *desc;
66 struct gpio_chip *gc;
67
68 gc = &chip->gc;
69 desc = &gc->gpiodev->descs[offset];
70
71 mutex_lock(&chip->lock);
72
73 if (test_bit(FLAG_REQUESTED, &desc->flags) &&
74 !test_bit(FLAG_IS_OUT, &desc->flags)) {
75 if (value == !!test_bit(offset, chip->value_map))
76 goto set_pull;
77
78 /*
79 * This is fine - it just means, nobody is listening
80 * for interrupts on this line, otherwise
81 * irq_create_mapping() would have been called from
82 * the to_irq() callback.
83 */
84 irq = irq_find_mapping(chip->irq_sim, offset);
85 if (!irq)
86 goto set_value;
87
88 irq_type = irq_get_trigger_type(irq);
89
90 if ((value && (irq_type & IRQ_TYPE_EDGE_RISING)) ||
91 (!value && (irq_type & IRQ_TYPE_EDGE_FALLING))) {
92 ret = irq_set_irqchip_state(irq, IRQCHIP_STATE_PENDING,
93 true);
94 if (ret)
95 goto set_pull;
96 }
97 }
98
99set_value:
100 /* Change the value unless we're actively driving the line. */
101 if (!test_bit(FLAG_REQUESTED, &desc->flags) ||
102 !test_bit(FLAG_IS_OUT, &desc->flags))
103 __assign_bit(offset, chip->value_map, value);
104
105set_pull:
106 __assign_bit(offset, chip->pull_map, value);
107 mutex_unlock(&chip->lock);
108 return 0;
109}
110
111static int gpio_sim_get(struct gpio_chip *gc, unsigned int offset)
112{
113 struct gpio_sim_chip *chip = gpiochip_get_data(gc);
114 int ret;
115
116 mutex_lock(&chip->lock);
117 ret = !!test_bit(offset, chip->value_map);
118 mutex_unlock(&chip->lock);
119
120 return ret;
121}
122
123static void gpio_sim_set(struct gpio_chip *gc, unsigned int offset, int value)
124{
125 struct gpio_sim_chip *chip = gpiochip_get_data(gc);
126
127 mutex_lock(&chip->lock);
128 __assign_bit(offset, chip->value_map, value);
129 mutex_unlock(&chip->lock);
130}
131
132static int gpio_sim_get_multiple(struct gpio_chip *gc,
133 unsigned long *mask, unsigned long *bits)
134{
135 struct gpio_sim_chip *chip = gpiochip_get_data(gc);
136
137 mutex_lock(&chip->lock);
138 bitmap_replace(bits, bits, chip->value_map, mask, gc->ngpio);
139 mutex_unlock(&chip->lock);
140
141 return 0;
142}
143
144static void gpio_sim_set_multiple(struct gpio_chip *gc,
145 unsigned long *mask, unsigned long *bits)
146{
147 struct gpio_sim_chip *chip = gpiochip_get_data(gc);
148
149 mutex_lock(&chip->lock);
150 bitmap_replace(chip->value_map, chip->value_map, bits, mask, gc->ngpio);
151 mutex_unlock(&chip->lock);
152}
153
154static int gpio_sim_direction_output(struct gpio_chip *gc,
155 unsigned int offset, int value)
156{
157 struct gpio_sim_chip *chip = gpiochip_get_data(gc);
158
159 mutex_lock(&chip->lock);
160 __clear_bit(offset, chip->direction_map);
161 __assign_bit(offset, chip->value_map, value);
162 mutex_unlock(&chip->lock);
163
164 return 0;
165}
166
167static int gpio_sim_direction_input(struct gpio_chip *gc, unsigned int offset)
168{
169 struct gpio_sim_chip *chip = gpiochip_get_data(gc);
170
171 mutex_lock(&chip->lock);
172 __set_bit(offset, chip->direction_map);
173 mutex_unlock(&chip->lock);
174
175 return 0;
176}
177
178static int gpio_sim_get_direction(struct gpio_chip *gc, unsigned int offset)
179{
180 struct gpio_sim_chip *chip = gpiochip_get_data(gc);
181 int direction;
182
183 mutex_lock(&chip->lock);
184 direction = !!test_bit(offset, chip->direction_map);
185 mutex_unlock(&chip->lock);
186
187 return direction ? GPIO_LINE_DIRECTION_IN : GPIO_LINE_DIRECTION_OUT;
188}
189
190static int gpio_sim_set_config(struct gpio_chip *gc,
191 unsigned int offset, unsigned long config)
192{
193 struct gpio_sim_chip *chip = gpiochip_get_data(gc);
194
195 switch (pinconf_to_config_param(config)) {
196 case PIN_CONFIG_BIAS_PULL_UP:
197 return gpio_sim_apply_pull(chip, offset, 1);
198 case PIN_CONFIG_BIAS_PULL_DOWN:
199 return gpio_sim_apply_pull(chip, offset, 0);
200 default:
201 break;
202 }
203
204 return -ENOTSUPP;
205}
206
207static int gpio_sim_to_irq(struct gpio_chip *gc, unsigned int offset)
208{
209 struct gpio_sim_chip *chip = gpiochip_get_data(gc);
210
211 return irq_create_mapping(chip->irq_sim, offset);
212}
213
214static void gpio_sim_free(struct gpio_chip *gc, unsigned int offset)
215{
216 struct gpio_sim_chip *chip = gpiochip_get_data(gc);
217
218 mutex_lock(&chip->lock);
219 __assign_bit(offset, chip->value_map, !!test_bit(offset, chip->pull_map));
220 mutex_unlock(&chip->lock);
221}
222
223static ssize_t gpio_sim_sysfs_val_show(struct device *dev,
224 struct device_attribute *attr, char *buf)
225{
226 struct gpio_sim_attribute *line_attr = to_gpio_sim_attr(attr);
227 struct gpio_sim_chip *chip = dev_get_drvdata(dev);
228 int val;
229
230 mutex_lock(&chip->lock);
231 val = !!test_bit(line_attr->offset, chip->value_map);
232 mutex_unlock(&chip->lock);
233
234 return sysfs_emit(buf, "%d\n", val);
235}
236
237static ssize_t gpio_sim_sysfs_val_store(struct device *dev,
238 struct device_attribute *attr,
239 const char *buf, size_t count)
240{
241 /*
242 * Not assigning this function will result in write() returning -EIO
243 * which is confusing. Return -EPERM explicitly.
244 */
245 return -EPERM;
246}
247
248static const char *const gpio_sim_sysfs_pull_strings[] = {
249 [0] = "pull-down",
250 [1] = "pull-up",
251};
252
253static ssize_t gpio_sim_sysfs_pull_show(struct device *dev,
254 struct device_attribute *attr,
255 char *buf)
256{
257 struct gpio_sim_attribute *line_attr = to_gpio_sim_attr(attr);
258 struct gpio_sim_chip *chip = dev_get_drvdata(dev);
259 int pull;
260
261 mutex_lock(&chip->lock);
262 pull = !!test_bit(line_attr->offset, chip->pull_map);
263 mutex_unlock(&chip->lock);
264
265 return sysfs_emit(buf, "%s\n", gpio_sim_sysfs_pull_strings[pull]);
266}
267
268static ssize_t gpio_sim_sysfs_pull_store(struct device *dev,
269 struct device_attribute *attr,
270 const char *buf, size_t len)
271{
272 struct gpio_sim_attribute *line_attr = to_gpio_sim_attr(attr);
273 struct gpio_sim_chip *chip = dev_get_drvdata(dev);
274 int ret, pull;
275
276 pull = sysfs_match_string(gpio_sim_sysfs_pull_strings, buf);
277 if (pull < 0)
278 return pull;
279
280 ret = gpio_sim_apply_pull(chip, line_attr->offset, pull);
281 if (ret)
282 return ret;
283
284 return len;
285}
286
287static void gpio_sim_mutex_destroy(void *data)
288{
289 struct mutex *lock = data;
290
291 mutex_destroy(lock);
292}
293
294static void gpio_sim_sysfs_remove(void *data)
295{
296 struct gpio_sim_chip *chip = data;
297
298 sysfs_remove_groups(&chip->gc.gpiodev->dev.kobj, chip->attr_groups);
299}
300
301static int gpio_sim_setup_sysfs(struct gpio_sim_chip *chip)
302{
303 struct device_attribute *val_dev_attr, *pull_dev_attr;
304 struct gpio_sim_attribute *val_attr, *pull_attr;
305 unsigned int num_lines = chip->gc.ngpio;
306 struct device *dev = chip->gc.parent;
307 struct attribute_group *attr_group;
308 struct attribute **attrs;
309 int i, ret;
310
311 chip->attr_groups = devm_kcalloc(dev, sizeof(*chip->attr_groups),
312 num_lines + 1, GFP_KERNEL);
313 if (!chip->attr_groups)
314 return -ENOMEM;
315
316 for (i = 0; i < num_lines; i++) {
317 attr_group = devm_kzalloc(dev, sizeof(*attr_group), GFP_KERNEL);
318 attrs = devm_kcalloc(dev, GPIO_SIM_NUM_ATTRS, sizeof(*attrs),
319 GFP_KERNEL);
320 val_attr = devm_kzalloc(dev, sizeof(*val_attr), GFP_KERNEL);
321 pull_attr = devm_kzalloc(dev, sizeof(*pull_attr), GFP_KERNEL);
322 if (!attr_group || !attrs || !val_attr || !pull_attr)
323 return -ENOMEM;
324
325 attr_group->name = devm_kasprintf(dev, GFP_KERNEL,
326 "sim_gpio%u", i);
327 if (!attr_group->name)
328 return -ENOMEM;
329
330 val_attr->offset = pull_attr->offset = i;
331
332 val_dev_attr = &val_attr->dev_attr;
333 pull_dev_attr = &pull_attr->dev_attr;
334
335 sysfs_attr_init(&val_dev_attr->attr);
336 sysfs_attr_init(&pull_dev_attr->attr);
337
338 val_dev_attr->attr.name = "value";
339 pull_dev_attr->attr.name = "pull";
340
341 val_dev_attr->attr.mode = pull_dev_attr->attr.mode = 0644;
342
343 val_dev_attr->show = gpio_sim_sysfs_val_show;
344 val_dev_attr->store = gpio_sim_sysfs_val_store;
345 pull_dev_attr->show = gpio_sim_sysfs_pull_show;
346 pull_dev_attr->store = gpio_sim_sysfs_pull_store;
347
348 attrs[0] = &val_dev_attr->attr;
349 attrs[1] = &pull_dev_attr->attr;
350
351 attr_group->attrs = attrs;
352 chip->attr_groups[i] = attr_group;
353 }
354
355 ret = sysfs_create_groups(&chip->gc.gpiodev->dev.kobj,
356 chip->attr_groups);
357 if (ret)
358 return ret;
359
360 return devm_add_action_or_reset(dev, gpio_sim_sysfs_remove, chip);
361}
362
363static int gpio_sim_add_bank(struct fwnode_handle *swnode, struct device *dev)
364{
365 struct gpio_sim_chip *chip;
366 struct gpio_chip *gc;
367 const char *label;
368 u32 num_lines;
369 int ret;
370
371 ret = fwnode_property_read_u32(swnode, "ngpios", &num_lines);
372 if (ret)
373 return ret;
374
375 if (num_lines > GPIO_SIM_NGPIO_MAX)
376 return -ERANGE;
377
378 ret = fwnode_property_read_string(swnode, "gpio-sim,label", &label);
379 if (ret) {
380 label = devm_kasprintf(dev, GFP_KERNEL, "%s-%s",
381 dev_name(dev), fwnode_get_name(swnode));
382 if (!label)
383 return -ENOMEM;
384 }
385
386 chip = devm_kzalloc(dev, sizeof(*chip), GFP_KERNEL);
387 if (!chip)
388 return -ENOMEM;
389
390 chip->direction_map = devm_bitmap_alloc(dev, num_lines, GFP_KERNEL);
391 if (!chip->direction_map)
392 return -ENOMEM;
393
394 /* Default to input mode. */
395 bitmap_fill(chip->direction_map, num_lines);
396
397 chip->value_map = devm_bitmap_zalloc(dev, num_lines, GFP_KERNEL);
398 if (!chip->value_map)
399 return -ENOMEM;
400
401 chip->pull_map = devm_bitmap_zalloc(dev, num_lines, GFP_KERNEL);
402 if (!chip->pull_map)
403 return -ENOMEM;
404
405 chip->irq_sim = devm_irq_domain_create_sim(dev, NULL, num_lines);
406 if (IS_ERR(chip->irq_sim))
407 return PTR_ERR(chip->irq_sim);
408
409 mutex_init(&chip->lock);
410 ret = devm_add_action_or_reset(dev, gpio_sim_mutex_destroy,
411 &chip->lock);
412 if (ret)
413 return ret;
414
415 gc = &chip->gc;
416 gc->base = -1;
417 gc->ngpio = num_lines;
418 gc->label = label;
419 gc->owner = THIS_MODULE;
420 gc->parent = dev;
421 gc->fwnode = swnode;
422 gc->get = gpio_sim_get;
423 gc->set = gpio_sim_set;
424 gc->get_multiple = gpio_sim_get_multiple;
425 gc->set_multiple = gpio_sim_set_multiple;
426 gc->direction_output = gpio_sim_direction_output;
427 gc->direction_input = gpio_sim_direction_input;
428 gc->get_direction = gpio_sim_get_direction;
429 gc->set_config = gpio_sim_set_config;
430 gc->to_irq = gpio_sim_to_irq;
431 gc->free = gpio_sim_free;
432
433 ret = devm_gpiochip_add_data(dev, gc, chip);
434 if (ret)
435 return ret;
436
437 /* Used by sysfs and configfs callbacks. */
438 dev_set_drvdata(&gc->gpiodev->dev, chip);
439
440 return gpio_sim_setup_sysfs(chip);
441}
442
443static int gpio_sim_probe(struct platform_device *pdev)
444{
445 struct device *dev = &pdev->dev;
446 struct fwnode_handle *swnode;
447 int ret;
448
449 device_for_each_child_node(dev, swnode) {
450 ret = gpio_sim_add_bank(swnode, dev);
451 if (ret) {
452 fwnode_handle_put(swnode);
453 return ret;
454 }
455 }
456
457 return 0;
458}
459
460static const struct of_device_id gpio_sim_of_match[] = {
461 { .compatible = "gpio-simulator" },
462 { }
463};
464MODULE_DEVICE_TABLE(of, gpio_sim_of_match);
465
466static struct platform_driver gpio_sim_driver = {
467 .driver = {
468 .name = "gpio-sim",
469 .of_match_table = gpio_sim_of_match,
470 },
471 .probe = gpio_sim_probe,
472};
473
474struct gpio_sim_device {
475 struct config_group group;
476
477 /*
478 * If pdev is NULL, the device is 'pending' (waiting for configuration).
479 * Once the pointer is assigned, the device has been created and the
480 * item is 'live'.
481 */
482 struct platform_device *pdev;
483 int id;
484
485 /*
486 * Each configfs filesystem operation is protected with the subsystem
487 * mutex. Each separate attribute is protected with the buffer mutex.
488 * This structure however can be modified by callbacks of different
489 * attributes so we need another lock.
490 *
491 * We use this lock fo protecting all data structures owned by this
492 * object too.
493 */
494 struct mutex lock;
495
496 /*
497 * This is used to synchronously wait for the driver's probe to complete
498 * and notify the user-space about any errors.
499 */
500 struct notifier_block bus_notifier;
501 struct completion probe_completion;
502 bool driver_bound;
503
504 struct gpiod_hog *hogs;
505
506 struct list_head bank_list;
507};
508
509/* This is called with dev->lock already taken. */
510static int gpio_sim_bus_notifier_call(struct notifier_block *nb,
511 unsigned long action, void *data)
512{
513 struct gpio_sim_device *simdev = container_of(nb,
514 struct gpio_sim_device,
515 bus_notifier);
516 struct device *dev = data;
517 char devname[32];
518
519 snprintf(devname, sizeof(devname), "gpio-sim.%u", simdev->id);
520
521 if (strcmp(dev_name(dev), devname) == 0) {
522 if (action == BUS_NOTIFY_BOUND_DRIVER)
523 simdev->driver_bound = true;
524 else if (action == BUS_NOTIFY_DRIVER_NOT_BOUND)
525 simdev->driver_bound = false;
526 else
527 return NOTIFY_DONE;
528
529 complete(&simdev->probe_completion);
530 return NOTIFY_OK;
531 }
532
533 return NOTIFY_DONE;
534}
535
536static struct gpio_sim_device *to_gpio_sim_device(struct config_item *item)
537{
538 struct config_group *group = to_config_group(item);
539
540 return container_of(group, struct gpio_sim_device, group);
541}
542
543struct gpio_sim_bank {
544 struct config_group group;
545
546 /*
547 * We could have used the ci_parent field of the config_item but
548 * configfs is stupid and calls the item's release callback after
549 * already having cleared the parent pointer even though the parent
550 * is guaranteed to survive the child...
551 *
552 * So we need to store the pointer to the parent struct here. We can
553 * dereference it anywhere we need with no checks and no locking as
554 * it's guaranteed to survive the children and protected by configfs
555 * locks.
556 *
557 * Same for other structures.
558 */
559 struct gpio_sim_device *parent;
560 struct list_head siblings;
561
562 char *label;
563 unsigned int num_lines;
564
565 struct list_head line_list;
566
567 struct fwnode_handle *swnode;
568};
569
570static struct gpio_sim_bank *to_gpio_sim_bank(struct config_item *item)
571{
572 struct config_group *group = to_config_group(item);
573
574 return container_of(group, struct gpio_sim_bank, group);
575}
576
577static bool gpio_sim_bank_has_label(struct gpio_sim_bank *bank)
578{
579 return bank->label && *bank->label;
580}
581
582static struct gpio_sim_device *
583gpio_sim_bank_get_device(struct gpio_sim_bank *bank)
584{
585 return bank->parent;
586}
587
588struct gpio_sim_hog;
589
590struct gpio_sim_line {
591 struct config_group group;
592
593 struct gpio_sim_bank *parent;
594 struct list_head siblings;
595
596 unsigned int offset;
597 char *name;
598
599 /* There can only be one hog per line. */
600 struct gpio_sim_hog *hog;
601};
602
603static struct gpio_sim_line *to_gpio_sim_line(struct config_item *item)
604{
605 struct config_group *group = to_config_group(item);
606
607 return container_of(group, struct gpio_sim_line, group);
608}
609
610static struct gpio_sim_device *
611gpio_sim_line_get_device(struct gpio_sim_line *line)
612{
613 struct gpio_sim_bank *bank = line->parent;
614
615 return gpio_sim_bank_get_device(bank);
616}
617
618struct gpio_sim_hog {
619 struct config_item item;
620 struct gpio_sim_line *parent;
621
622 char *name;
623 int dir;
624};
625
626static struct gpio_sim_hog *to_gpio_sim_hog(struct config_item *item)
627{
628 return container_of(item, struct gpio_sim_hog, item);
629}
630
631static struct gpio_sim_device *gpio_sim_hog_get_device(struct gpio_sim_hog *hog)
632{
633 struct gpio_sim_line *line = hog->parent;
634
635 return gpio_sim_line_get_device(line);
636}
637
638static bool gpio_sim_device_is_live_unlocked(struct gpio_sim_device *dev)
639{
640 return !!dev->pdev;
641}
642
643static char *gpio_sim_strdup_trimmed(const char *str, size_t count)
644{
645 char *dup, *trimmed;
646
647 dup = kstrndup(str, count, GFP_KERNEL);
648 if (!dup)
649 return NULL;
650
651 trimmed = strstrip(dup);
652 memmove(dup, trimmed, strlen(trimmed) + 1);
653
654 return dup;
655}
656
657static ssize_t gpio_sim_device_config_dev_name_show(struct config_item *item,
658 char *page)
659{
660 struct gpio_sim_device *dev = to_gpio_sim_device(item);
661 struct platform_device *pdev;
662 int ret;
663
664 mutex_lock(&dev->lock);
665 pdev = dev->pdev;
666 if (pdev)
667 ret = sprintf(page, "%s\n", dev_name(&pdev->dev));
668 else
669 ret = sprintf(page, "gpio-sim.%d\n", dev->id);
670 mutex_unlock(&dev->lock);
671
672 return ret;
673}
674
675CONFIGFS_ATTR_RO(gpio_sim_device_config_, dev_name);
676
677static ssize_t
678gpio_sim_device_config_live_show(struct config_item *item, char *page)
679{
680 struct gpio_sim_device *dev = to_gpio_sim_device(item);
681 bool live;
682
683 mutex_lock(&dev->lock);
684 live = gpio_sim_device_is_live_unlocked(dev);
685 mutex_unlock(&dev->lock);
686
687 return sprintf(page, "%c\n", live ? '1' : '0');
688}
689
690static char **gpio_sim_make_line_names(struct gpio_sim_bank *bank,
691 unsigned int *line_names_size)
692{
693 unsigned int max_offset = 0;
694 bool has_line_names = false;
695 struct gpio_sim_line *line;
696 char **line_names;
697
698 list_for_each_entry(line, &bank->line_list, siblings) {
699 if (line->name) {
700 if (line->offset > max_offset)
701 max_offset = line->offset;
702
703 /*
704 * max_offset can stay at 0 so it's not an indicator
705 * of whether line names were configured at all.
706 */
707 has_line_names = true;
708 }
709 }
710
711 if (!has_line_names)
712 /*
713 * This is not an error - NULL means, there are no line
714 * names configured.
715 */
716 return NULL;
717
718 *line_names_size = max_offset + 1;
719
720 line_names = kcalloc(*line_names_size, sizeof(*line_names), GFP_KERNEL);
721 if (!line_names)
722 return ERR_PTR(-ENOMEM);
723
724 list_for_each_entry(line, &bank->line_list, siblings)
725 line_names[line->offset] = line->name;
726
727 return line_names;
728}
729
730static void gpio_sim_remove_hogs(struct gpio_sim_device *dev)
731{
732 struct gpiod_hog *hog;
733
734 if (!dev->hogs)
735 return;
736
737 gpiod_remove_hogs(dev->hogs);
738
739 for (hog = dev->hogs; hog->chip_label; hog++) {
740 kfree(hog->chip_label);
741 kfree(hog->line_name);
742 }
743
744 kfree(dev->hogs);
745 dev->hogs = NULL;
746}
747
748static int gpio_sim_add_hogs(struct gpio_sim_device *dev)
749{
750 unsigned int num_hogs = 0, idx = 0;
751 struct gpio_sim_bank *bank;
752 struct gpio_sim_line *line;
753 struct gpiod_hog *hog;
754
755 list_for_each_entry(bank, &dev->bank_list, siblings) {
756 list_for_each_entry(line, &bank->line_list, siblings) {
757 if (line->hog)
758 num_hogs++;
759 }
760 }
761
762 if (!num_hogs)
763 return 0;
764
765 /* Allocate one more for the sentinel. */
766 dev->hogs = kcalloc(num_hogs + 1, sizeof(*dev->hogs), GFP_KERNEL);
767 if (!dev->hogs)
768 return -ENOMEM;
769
770 list_for_each_entry(bank, &dev->bank_list, siblings) {
771 list_for_each_entry(line, &bank->line_list, siblings) {
772 if (!line->hog)
773 continue;
774
775 hog = &dev->hogs[idx++];
776
777 /*
778 * We need to make this string manually because at this
779 * point the device doesn't exist yet and so dev_name()
780 * is not available.
781 */
782 if (gpio_sim_bank_has_label(bank))
783 hog->chip_label = kstrdup(bank->label,
784 GFP_KERNEL);
785 else
786 hog->chip_label = kasprintf(GFP_KERNEL,
787 "gpio-sim.%u-%s",
788 dev->id,
789 fwnode_get_name(
790 bank->swnode));
791 if (!hog->chip_label) {
792 gpio_sim_remove_hogs(dev);
793 return -ENOMEM;
794 }
795
796 /*
797 * We need to duplicate this because the hog config
798 * item can be removed at any time (and we can't block
799 * it) and gpiolib doesn't make a deep copy of the hog
800 * data.
801 */
802 if (line->hog->name) {
803 hog->line_name = kstrdup(line->hog->name,
804 GFP_KERNEL);
805 if (!hog->line_name) {
806 gpio_sim_remove_hogs(dev);
807 return -ENOMEM;
808 }
809 }
810
811 hog->chip_hwnum = line->offset;
812 hog->dflags = line->hog->dir;
813 }
814 }
815
816 gpiod_add_hogs(dev->hogs);
817
818 return 0;
819}
820
821static struct fwnode_handle *
822gpio_sim_make_bank_swnode(struct gpio_sim_bank *bank,
823 struct fwnode_handle *parent)
824{
825 struct property_entry properties[GPIO_SIM_PROP_MAX];
826 unsigned int prop_idx = 0, line_names_size = 0;
827 struct fwnode_handle *swnode;
828 char **line_names;
829
830 memset(properties, 0, sizeof(properties));
831
832 properties[prop_idx++] = PROPERTY_ENTRY_U32("ngpios", bank->num_lines);
833
834 if (gpio_sim_bank_has_label(bank))
835 properties[prop_idx++] = PROPERTY_ENTRY_STRING("gpio-sim,label",
836 bank->label);
837
838 line_names = gpio_sim_make_line_names(bank, &line_names_size);
839 if (IS_ERR(line_names))
840 return ERR_CAST(line_names);
841
842 if (line_names)
843 properties[prop_idx++] = PROPERTY_ENTRY_STRING_ARRAY_LEN(
844 "gpio-line-names",
845 line_names, line_names_size);
846
847 swnode = fwnode_create_software_node(properties, parent);
848 kfree(line_names);
849 return swnode;
850}
851
852static void gpio_sim_remove_swnode_recursive(struct fwnode_handle *swnode)
853{
854 struct fwnode_handle *child;
855
856 fwnode_for_each_child_node(swnode, child)
857 fwnode_remove_software_node(child);
858
859 fwnode_remove_software_node(swnode);
860}
861
862static bool gpio_sim_bank_labels_non_unique(struct gpio_sim_device *dev)
863{
864 struct gpio_sim_bank *this, *pos;
865
866 list_for_each_entry(this, &dev->bank_list, siblings) {
867 list_for_each_entry(pos, &dev->bank_list, siblings) {
868 if (this == pos || (!this->label || !pos->label))
869 continue;
870
871 if (strcmp(this->label, pos->label) == 0)
872 return true;
873 }
874 }
875
876 return false;
877}
878
879static int gpio_sim_device_activate_unlocked(struct gpio_sim_device *dev)
880{
881 struct platform_device_info pdevinfo;
882 struct fwnode_handle *swnode;
883 struct platform_device *pdev;
884 struct gpio_sim_bank *bank;
885 int ret;
886
887 if (list_empty(&dev->bank_list))
888 return -ENODATA;
889
890 /*
891 * Non-unique GPIO device labels are a corner-case we don't support
892 * as it would interfere with machine hogging mechanism and has little
893 * use in real life.
894 */
895 if (gpio_sim_bank_labels_non_unique(dev))
896 return -EINVAL;
897
898 memset(&pdevinfo, 0, sizeof(pdevinfo));
899
900 swnode = fwnode_create_software_node(NULL, NULL);
901 if (IS_ERR(swnode))
902 return PTR_ERR(swnode);
903
904 list_for_each_entry(bank, &dev->bank_list, siblings) {
905 bank->swnode = gpio_sim_make_bank_swnode(bank, swnode);
906 if (IS_ERR(bank->swnode)) {
907 ret = PTR_ERR(bank->swnode);
908 gpio_sim_remove_swnode_recursive(swnode);
909 return ret;
910 }
911 }
912
913 ret = gpio_sim_add_hogs(dev);
914 if (ret) {
915 gpio_sim_remove_swnode_recursive(swnode);
916 return ret;
917 }
918
919 pdevinfo.name = "gpio-sim";
920 pdevinfo.fwnode = swnode;
921 pdevinfo.id = dev->id;
922
923 reinit_completion(&dev->probe_completion);
924 dev->driver_bound = false;
925 bus_register_notifier(&platform_bus_type, &dev->bus_notifier);
926
927 pdev = platform_device_register_full(&pdevinfo);
928 if (IS_ERR(pdev)) {
929 bus_unregister_notifier(&platform_bus_type, &dev->bus_notifier);
930 gpio_sim_remove_hogs(dev);
931 gpio_sim_remove_swnode_recursive(swnode);
932 return PTR_ERR(pdev);
933 }
934
935 wait_for_completion(&dev->probe_completion);
936 bus_unregister_notifier(&platform_bus_type, &dev->bus_notifier);
937
938 if (!dev->driver_bound) {
939 /* Probe failed, check kernel log. */
940 platform_device_unregister(pdev);
941 gpio_sim_remove_hogs(dev);
942 gpio_sim_remove_swnode_recursive(swnode);
943 return -ENXIO;
944 }
945
946 dev->pdev = pdev;
947
948 return 0;
949}
950
951static void gpio_sim_device_deactivate_unlocked(struct gpio_sim_device *dev)
952{
953 struct fwnode_handle *swnode;
954
955 swnode = dev_fwnode(&dev->pdev->dev);
956 platform_device_unregister(dev->pdev);
957 gpio_sim_remove_swnode_recursive(swnode);
958 dev->pdev = NULL;
959 gpio_sim_remove_hogs(dev);
960}
961
962static ssize_t
963gpio_sim_device_config_live_store(struct config_item *item,
964 const char *page, size_t count)
965{
966 struct gpio_sim_device *dev = to_gpio_sim_device(item);
967 bool live;
968 int ret;
969
970 ret = kstrtobool(page, &live);
971 if (ret)
972 return ret;
973
974 mutex_lock(&dev->lock);
975
976 if ((!live && !gpio_sim_device_is_live_unlocked(dev)) ||
977 (live && gpio_sim_device_is_live_unlocked(dev)))
978 ret = -EPERM;
979 else if (live)
980 ret = gpio_sim_device_activate_unlocked(dev);
981 else
982 gpio_sim_device_deactivate_unlocked(dev);
983
984 mutex_unlock(&dev->lock);
985
986 return ret ?: count;
987}
988
989CONFIGFS_ATTR(gpio_sim_device_config_, live);
990
991static struct configfs_attribute *gpio_sim_device_config_attrs[] = {
992 &gpio_sim_device_config_attr_dev_name,
993 &gpio_sim_device_config_attr_live,
994 NULL
995};
996
997struct gpio_sim_chip_name_ctx {
998 struct fwnode_handle *swnode;
999 char *page;
1000};
1001
1002static int gpio_sim_emit_chip_name(struct device *dev, void *data)
1003{
1004 struct gpio_sim_chip_name_ctx *ctx = data;
1005
1006 /* This would be the sysfs device exported in /sys/class/gpio. */
1007 if (dev->class)
1008 return 0;
1009
1010 if (device_match_fwnode(dev, ctx->swnode))
1011 return sprintf(ctx->page, "%s\n", dev_name(dev));
1012
1013 return 0;
1014}
1015
1016static ssize_t gpio_sim_bank_config_chip_name_show(struct config_item *item,
1017 char *page)
1018{
1019 struct gpio_sim_bank *bank = to_gpio_sim_bank(item);
1020 struct gpio_sim_device *dev = gpio_sim_bank_get_device(bank);
1021 struct gpio_sim_chip_name_ctx ctx = { bank->swnode, page };
1022 int ret;
1023
1024 mutex_lock(&dev->lock);
1025 if (gpio_sim_device_is_live_unlocked(dev))
1026 ret = device_for_each_child(&dev->pdev->dev, &ctx,
1027 gpio_sim_emit_chip_name);
1028 else
1029 ret = sprintf(page, "none\n");
1030 mutex_unlock(&dev->lock);
1031
1032 return ret;
1033}
1034
1035CONFIGFS_ATTR_RO(gpio_sim_bank_config_, chip_name);
1036
1037static ssize_t
1038gpio_sim_bank_config_label_show(struct config_item *item, char *page)
1039{
1040 struct gpio_sim_bank *bank = to_gpio_sim_bank(item);
1041 struct gpio_sim_device *dev = gpio_sim_bank_get_device(bank);
1042 int ret;
1043
1044 mutex_lock(&dev->lock);
1045 ret = sprintf(page, "%s\n", bank->label ?: "");
1046 mutex_unlock(&dev->lock);
1047
1048 return ret;
1049}
1050
1051static ssize_t gpio_sim_bank_config_label_store(struct config_item *item,
1052 const char *page, size_t count)
1053{
1054 struct gpio_sim_bank *bank = to_gpio_sim_bank(item);
1055 struct gpio_sim_device *dev = gpio_sim_bank_get_device(bank);
1056 char *trimmed;
1057
1058 mutex_lock(&dev->lock);
1059
1060 if (gpio_sim_device_is_live_unlocked(dev)) {
1061 mutex_unlock(&dev->lock);
1062 return -EBUSY;
1063 }
1064
1065 trimmed = gpio_sim_strdup_trimmed(page, count);
1066 if (!trimmed) {
1067 mutex_unlock(&dev->lock);
1068 return -ENOMEM;
1069 }
1070
1071 kfree(bank->label);
1072 bank->label = trimmed;
1073
1074 mutex_unlock(&dev->lock);
1075 return count;
1076}
1077
1078CONFIGFS_ATTR(gpio_sim_bank_config_, label);
1079
1080static ssize_t
1081gpio_sim_bank_config_num_lines_show(struct config_item *item, char *page)
1082{
1083 struct gpio_sim_bank *bank = to_gpio_sim_bank(item);
1084 struct gpio_sim_device *dev = gpio_sim_bank_get_device(bank);
1085 int ret;
1086
1087 mutex_lock(&dev->lock);
1088 ret = sprintf(page, "%u\n", bank->num_lines);
1089 mutex_unlock(&dev->lock);
1090
1091 return ret;
1092}
1093
1094static ssize_t
1095gpio_sim_bank_config_num_lines_store(struct config_item *item,
1096 const char *page, size_t count)
1097{
1098 struct gpio_sim_bank *bank = to_gpio_sim_bank(item);
1099 struct gpio_sim_device *dev = gpio_sim_bank_get_device(bank);
1100 unsigned int num_lines;
1101 int ret;
1102
1103 ret = kstrtouint(page, 0, &num_lines);
1104 if (ret)
1105 return ret;
1106
1107 if (num_lines == 0)
1108 return -EINVAL;
1109
1110 mutex_lock(&dev->lock);
1111
1112 if (gpio_sim_device_is_live_unlocked(dev)) {
1113 mutex_unlock(&dev->lock);
1114 return -EBUSY;
1115 }
1116
1117 bank->num_lines = num_lines;
1118
1119 mutex_unlock(&dev->lock);
1120 return count;
1121}
1122
1123CONFIGFS_ATTR(gpio_sim_bank_config_, num_lines);
1124
1125static struct configfs_attribute *gpio_sim_bank_config_attrs[] = {
1126 &gpio_sim_bank_config_attr_chip_name,
1127 &gpio_sim_bank_config_attr_label,
1128 &gpio_sim_bank_config_attr_num_lines,
1129 NULL
1130};
1131
1132static ssize_t
1133gpio_sim_line_config_name_show(struct config_item *item, char *page)
1134{
1135 struct gpio_sim_line *line = to_gpio_sim_line(item);
1136 struct gpio_sim_device *dev = gpio_sim_line_get_device(line);
1137 int ret;
1138
1139 mutex_lock(&dev->lock);
1140 ret = sprintf(page, "%s\n", line->name ?: "");
1141 mutex_unlock(&dev->lock);
1142
1143 return ret;
1144}
1145
1146static ssize_t gpio_sim_line_config_name_store(struct config_item *item,
1147 const char *page, size_t count)
1148{
1149 struct gpio_sim_line *line = to_gpio_sim_line(item);
1150 struct gpio_sim_device *dev = gpio_sim_line_get_device(line);
1151 char *trimmed;
1152
1153 mutex_lock(&dev->lock);
1154
1155 if (gpio_sim_device_is_live_unlocked(dev)) {
1156 mutex_unlock(&dev->lock);
1157 return -EBUSY;
1158 }
1159
1160 trimmed = gpio_sim_strdup_trimmed(page, count);
1161 if (!trimmed) {
1162 mutex_unlock(&dev->lock);
1163 return -ENOMEM;
1164 }
1165
1166 kfree(line->name);
1167 line->name = trimmed;
1168
1169 mutex_unlock(&dev->lock);
1170
1171 return count;
1172}
1173
1174CONFIGFS_ATTR(gpio_sim_line_config_, name);
1175
1176static struct configfs_attribute *gpio_sim_line_config_attrs[] = {
1177 &gpio_sim_line_config_attr_name,
1178 NULL
1179};
1180
1181static ssize_t gpio_sim_hog_config_name_show(struct config_item *item,
1182 char *page)
1183{
1184 struct gpio_sim_hog *hog = to_gpio_sim_hog(item);
1185 struct gpio_sim_device *dev = gpio_sim_hog_get_device(hog);
1186 int ret;
1187
1188 mutex_lock(&dev->lock);
1189 ret = sprintf(page, "%s\n", hog->name ?: "");
1190 mutex_unlock(&dev->lock);
1191
1192 return ret;
1193}
1194
1195static ssize_t gpio_sim_hog_config_name_store(struct config_item *item,
1196 const char *page, size_t count)
1197{
1198 struct gpio_sim_hog *hog = to_gpio_sim_hog(item);
1199 struct gpio_sim_device *dev = gpio_sim_hog_get_device(hog);
1200 char *trimmed;
1201
1202 mutex_lock(&dev->lock);
1203
1204 if (gpio_sim_device_is_live_unlocked(dev)) {
1205 mutex_unlock(&dev->lock);
1206 return -EBUSY;
1207 }
1208
1209 trimmed = gpio_sim_strdup_trimmed(page, count);
1210 if (!trimmed) {
1211 mutex_unlock(&dev->lock);
1212 return -ENOMEM;
1213 }
1214
1215 kfree(hog->name);
1216 hog->name = trimmed;
1217
1218 mutex_unlock(&dev->lock);
1219
1220 return count;
1221}
1222
1223CONFIGFS_ATTR(gpio_sim_hog_config_, name);
1224
1225static ssize_t gpio_sim_hog_config_direction_show(struct config_item *item,
1226 char *page)
1227{
1228 struct gpio_sim_hog *hog = to_gpio_sim_hog(item);
1229 struct gpio_sim_device *dev = gpio_sim_hog_get_device(hog);
1230 char *repr;
1231 int dir;
1232
1233 mutex_lock(&dev->lock);
1234 dir = hog->dir;
1235 mutex_unlock(&dev->lock);
1236
1237 switch (dir) {
1238 case GPIOD_IN:
1239 repr = "input";
1240 break;
1241 case GPIOD_OUT_HIGH:
1242 repr = "output-high";
1243 break;
1244 case GPIOD_OUT_LOW:
1245 repr = "output-low";
1246 break;
1247 default:
1248 /* This would be a programmer bug. */
1249 WARN(1, "Unexpected hog direction value: %d", dir);
1250 return -EINVAL;
1251 }
1252
1253 return sprintf(page, "%s\n", repr);
1254}
1255
1256static ssize_t
1257gpio_sim_hog_config_direction_store(struct config_item *item,
1258 const char *page, size_t count)
1259{
1260 struct gpio_sim_hog *hog = to_gpio_sim_hog(item);
1261 struct gpio_sim_device *dev = gpio_sim_hog_get_device(hog);
1262 char *trimmed;
1263 int dir;
1264
1265 mutex_lock(&dev->lock);
1266
1267 if (gpio_sim_device_is_live_unlocked(dev)) {
1268 mutex_unlock(&dev->lock);
1269 return -EBUSY;
1270 }
1271
1272 trimmed = gpio_sim_strdup_trimmed(page, count);
1273 if (!trimmed) {
1274 mutex_unlock(&dev->lock);
1275 return -ENOMEM;
1276 }
1277
1278 if (strcmp(trimmed, "input") == 0)
1279 dir = GPIOD_IN;
1280 else if (strcmp(trimmed, "output-high") == 0)
1281 dir = GPIOD_OUT_HIGH;
1282 else if (strcmp(trimmed, "output-low") == 0)
1283 dir = GPIOD_OUT_LOW;
1284 else
1285 dir = -EINVAL;
1286
1287 kfree(trimmed);
1288
1289 if (dir < 0) {
1290 mutex_unlock(&dev->lock);
1291 return dir;
1292 }
1293
1294 hog->dir = dir;
1295
1296 mutex_unlock(&dev->lock);
1297
1298 return count;
1299}
1300
1301CONFIGFS_ATTR(gpio_sim_hog_config_, direction);
1302
1303static struct configfs_attribute *gpio_sim_hog_config_attrs[] = {
1304 &gpio_sim_hog_config_attr_name,
1305 &gpio_sim_hog_config_attr_direction,
1306 NULL
1307};
1308
1309static void gpio_sim_hog_config_item_release(struct config_item *item)
1310{
1311 struct gpio_sim_hog *hog = to_gpio_sim_hog(item);
1312 struct gpio_sim_line *line = hog->parent;
1313 struct gpio_sim_device *dev = gpio_sim_hog_get_device(hog);
1314
1315 mutex_lock(&dev->lock);
1316 line->hog = NULL;
1317 mutex_unlock(&dev->lock);
1318
1319 kfree(hog->name);
1320 kfree(hog);
1321}
1322
1323static struct configfs_item_operations gpio_sim_hog_config_item_ops = {
1324 .release = gpio_sim_hog_config_item_release,
1325};
1326
1327static const struct config_item_type gpio_sim_hog_config_type = {
1328 .ct_item_ops = &gpio_sim_hog_config_item_ops,
1329 .ct_attrs = gpio_sim_hog_config_attrs,
1330 .ct_owner = THIS_MODULE,
1331};
1332
1333static struct config_item *
1334gpio_sim_line_config_make_hog_item(struct config_group *group, const char *name)
1335{
1336 struct gpio_sim_line *line = to_gpio_sim_line(&group->cg_item);
1337 struct gpio_sim_device *dev = gpio_sim_line_get_device(line);
1338 struct gpio_sim_hog *hog;
1339
1340 if (strcmp(name, "hog") != 0)
1341 return ERR_PTR(-EINVAL);
1342
1343 mutex_lock(&dev->lock);
1344
1345 hog = kzalloc(sizeof(*hog), GFP_KERNEL);
1346 if (!hog) {
1347 mutex_unlock(&dev->lock);
1348 return ERR_PTR(-ENOMEM);
1349 }
1350
1351 config_item_init_type_name(&hog->item, name,
1352 &gpio_sim_hog_config_type);
1353
1354 hog->dir = GPIOD_IN;
1355 hog->name = NULL;
1356 hog->parent = line;
1357 line->hog = hog;
1358
1359 mutex_unlock(&dev->lock);
1360
1361 return &hog->item;
1362}
1363
1364static void gpio_sim_line_config_group_release(struct config_item *item)
1365{
1366 struct gpio_sim_line *line = to_gpio_sim_line(item);
1367 struct gpio_sim_device *dev = gpio_sim_line_get_device(line);
1368
1369 mutex_lock(&dev->lock);
1370 list_del(&line->siblings);
1371 mutex_unlock(&dev->lock);
1372
1373 kfree(line->name);
1374 kfree(line);
1375}
1376
1377static struct configfs_item_operations gpio_sim_line_config_item_ops = {
1378 .release = gpio_sim_line_config_group_release,
1379};
1380
1381static struct configfs_group_operations gpio_sim_line_config_group_ops = {
1382 .make_item = gpio_sim_line_config_make_hog_item,
1383};
1384
1385static const struct config_item_type gpio_sim_line_config_type = {
1386 .ct_item_ops = &gpio_sim_line_config_item_ops,
1387 .ct_group_ops = &gpio_sim_line_config_group_ops,
1388 .ct_attrs = gpio_sim_line_config_attrs,
1389 .ct_owner = THIS_MODULE,
1390};
1391
1392static struct config_group *
1393gpio_sim_bank_config_make_line_group(struct config_group *group,
1394 const char *name)
1395{
1396 struct gpio_sim_bank *bank = to_gpio_sim_bank(&group->cg_item);
1397 struct gpio_sim_device *dev = gpio_sim_bank_get_device(bank);
1398 struct gpio_sim_line *line;
1399 unsigned int offset;
1400 int ret, nchar;
1401
1402 ret = sscanf(name, "line%u%n", &offset, &nchar);
1403 if (ret != 1 || nchar != strlen(name))
1404 return ERR_PTR(-EINVAL);
1405
1406 mutex_lock(&dev->lock);
1407
1408 if (gpio_sim_device_is_live_unlocked(dev)) {
1409 mutex_unlock(&dev->lock);
1410 return ERR_PTR(-EBUSY);
1411 }
1412
1413 line = kzalloc(sizeof(*line), GFP_KERNEL);
1414 if (!line) {
1415 mutex_unlock(&dev->lock);
1416 return ERR_PTR(-ENOMEM);
1417 }
1418
1419 config_group_init_type_name(&line->group, name,
1420 &gpio_sim_line_config_type);
1421
1422 line->parent = bank;
1423 line->offset = offset;
1424 list_add_tail(&line->siblings, &bank->line_list);
1425
1426 mutex_unlock(&dev->lock);
1427
1428 return &line->group;
1429}
1430
1431static void gpio_sim_bank_config_group_release(struct config_item *item)
1432{
1433 struct gpio_sim_bank *bank = to_gpio_sim_bank(item);
1434 struct gpio_sim_device *dev = gpio_sim_bank_get_device(bank);
1435
1436 mutex_lock(&dev->lock);
1437 list_del(&bank->siblings);
1438 mutex_unlock(&dev->lock);
1439
1440 kfree(bank->label);
1441 kfree(bank);
1442}
1443
1444static struct configfs_item_operations gpio_sim_bank_config_item_ops = {
1445 .release = gpio_sim_bank_config_group_release,
1446};
1447
1448static struct configfs_group_operations gpio_sim_bank_config_group_ops = {
1449 .make_group = gpio_sim_bank_config_make_line_group,
1450};
1451
1452static const struct config_item_type gpio_sim_bank_config_group_type = {
1453 .ct_item_ops = &gpio_sim_bank_config_item_ops,
1454 .ct_group_ops = &gpio_sim_bank_config_group_ops,
1455 .ct_attrs = gpio_sim_bank_config_attrs,
1456 .ct_owner = THIS_MODULE,
1457};
1458
1459static struct config_group *
1460gpio_sim_device_config_make_bank_group(struct config_group *group,
1461 const char *name)
1462{
1463 struct gpio_sim_device *dev = to_gpio_sim_device(&group->cg_item);
1464 struct gpio_sim_bank *bank;
1465
1466 mutex_lock(&dev->lock);
1467
1468 if (gpio_sim_device_is_live_unlocked(dev)) {
1469 mutex_unlock(&dev->lock);
1470 return ERR_PTR(-EBUSY);
1471 }
1472
1473 bank = kzalloc(sizeof(*bank), GFP_KERNEL);
1474 if (!bank) {
1475 mutex_unlock(&dev->lock);
1476 return ERR_PTR(-ENOMEM);
1477 }
1478
1479 config_group_init_type_name(&bank->group, name,
1480 &gpio_sim_bank_config_group_type);
1481 bank->num_lines = 1;
1482 bank->parent = dev;
1483 INIT_LIST_HEAD(&bank->line_list);
1484 list_add_tail(&bank->siblings, &dev->bank_list);
1485
1486 mutex_unlock(&dev->lock);
1487
1488 return &bank->group;
1489}
1490
1491static void gpio_sim_device_config_group_release(struct config_item *item)
1492{
1493 struct gpio_sim_device *dev = to_gpio_sim_device(item);
1494
1495 mutex_lock(&dev->lock);
1496 if (gpio_sim_device_is_live_unlocked(dev))
1497 gpio_sim_device_deactivate_unlocked(dev);
1498 mutex_unlock(&dev->lock);
1499
1500 mutex_destroy(&dev->lock);
1501 ida_free(&gpio_sim_ida, dev->id);
1502 kfree(dev);
1503}
1504
1505static struct configfs_item_operations gpio_sim_device_config_item_ops = {
1506 .release = gpio_sim_device_config_group_release,
1507};
1508
1509static struct configfs_group_operations gpio_sim_device_config_group_ops = {
1510 .make_group = gpio_sim_device_config_make_bank_group,
1511};
1512
1513static const struct config_item_type gpio_sim_device_config_group_type = {
1514 .ct_item_ops = &gpio_sim_device_config_item_ops,
1515 .ct_group_ops = &gpio_sim_device_config_group_ops,
1516 .ct_attrs = gpio_sim_device_config_attrs,
1517 .ct_owner = THIS_MODULE,
1518};
1519
1520static struct config_group *
1521gpio_sim_config_make_device_group(struct config_group *group, const char *name)
1522{
1523 struct gpio_sim_device *dev;
1524 int id;
1525
1526 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
1527 if (!dev)
1528 return ERR_PTR(-ENOMEM);
1529
1530 id = ida_alloc(&gpio_sim_ida, GFP_KERNEL);
1531 if (id < 0) {
1532 kfree(dev);
1533 return ERR_PTR(id);
1534 }
1535
1536 config_group_init_type_name(&dev->group, name,
1537 &gpio_sim_device_config_group_type);
1538 dev->id = id;
1539 mutex_init(&dev->lock);
1540 INIT_LIST_HEAD(&dev->bank_list);
1541
1542 dev->bus_notifier.notifier_call = gpio_sim_bus_notifier_call;
1543 init_completion(&dev->probe_completion);
1544
1545 return &dev->group;
1546}
1547
1548static struct configfs_group_operations gpio_sim_config_group_ops = {
1549 .make_group = gpio_sim_config_make_device_group,
1550};
1551
1552static const struct config_item_type gpio_sim_config_type = {
1553 .ct_group_ops = &gpio_sim_config_group_ops,
1554 .ct_owner = THIS_MODULE,
1555};
1556
1557static struct configfs_subsystem gpio_sim_config_subsys = {
1558 .su_group = {
1559 .cg_item = {
1560 .ci_namebuf = "gpio-sim",
1561 .ci_type = &gpio_sim_config_type,
1562 },
1563 },
1564};
1565
1566static int __init gpio_sim_init(void)
1567{
1568 int ret;
1569
1570 ret = platform_driver_register(&gpio_sim_driver);
1571 if (ret) {
1572 pr_err("Error %d while registering the platform driver\n", ret);
1573 return ret;
1574 }
1575
1576 config_group_init(&gpio_sim_config_subsys.su_group);
1577 mutex_init(&gpio_sim_config_subsys.su_mutex);
1578 ret = configfs_register_subsystem(&gpio_sim_config_subsys);
1579 if (ret) {
1580 pr_err("Error %d while registering the configfs subsystem %s\n",
1581 ret, gpio_sim_config_subsys.su_group.cg_item.ci_namebuf);
1582 mutex_destroy(&gpio_sim_config_subsys.su_mutex);
1583 platform_driver_unregister(&gpio_sim_driver);
1584 return ret;
1585 }
1586
1587 return 0;
1588}
1589module_init(gpio_sim_init);
1590
1591static void __exit gpio_sim_exit(void)
1592{
1593 configfs_unregister_subsystem(&gpio_sim_config_subsys);
1594 mutex_destroy(&gpio_sim_config_subsys.su_mutex);
1595 platform_driver_unregister(&gpio_sim_driver);
1596}
1597module_exit(gpio_sim_exit);
1598
1599MODULE_AUTHOR("Bartosz Golaszewski <brgl@bgdev.pl");
1600MODULE_DESCRIPTION("GPIO Simulator Module");
1601MODULE_LICENSE("GPL");
1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * GPIO testing driver based on configfs.
4 *
5 * Copyright (C) 2021 Bartosz Golaszewski <brgl@bgdev.pl>
6 */
7
8#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
9
10#include <linux/bitmap.h>
11#include <linux/cleanup.h>
12#include <linux/completion.h>
13#include <linux/configfs.h>
14#include <linux/device.h>
15#include <linux/err.h>
16#include <linux/gpio/consumer.h>
17#include <linux/gpio/driver.h>
18#include <linux/gpio/machine.h>
19#include <linux/idr.h>
20#include <linux/interrupt.h>
21#include <linux/irq.h>
22#include <linux/irq_sim.h>
23#include <linux/kernel.h>
24#include <linux/list.h>
25#include <linux/lockdep.h>
26#include <linux/minmax.h>
27#include <linux/mod_devicetable.h>
28#include <linux/module.h>
29#include <linux/mutex.h>
30#include <linux/notifier.h>
31#include <linux/platform_device.h>
32#include <linux/property.h>
33#include <linux/seq_file.h>
34#include <linux/slab.h>
35#include <linux/string.h>
36#include <linux/string_helpers.h>
37#include <linux/sysfs.h>
38#include <linux/types.h>
39
40#define GPIO_SIM_NGPIO_MAX 1024
41#define GPIO_SIM_PROP_MAX 4 /* Max 3 properties + sentinel. */
42#define GPIO_SIM_NUM_ATTRS 3 /* value, pull and sentinel */
43
44static DEFINE_IDA(gpio_sim_ida);
45
46struct gpio_sim_chip {
47 struct gpio_chip gc;
48 struct device *dev;
49 unsigned long *request_map;
50 unsigned long *direction_map;
51 unsigned long *value_map;
52 unsigned long *pull_map;
53 struct irq_domain *irq_sim;
54 struct mutex lock;
55 const struct attribute_group **attr_groups;
56};
57
58struct gpio_sim_attribute {
59 struct device_attribute dev_attr;
60 unsigned int offset;
61};
62
63static struct gpio_sim_attribute *
64to_gpio_sim_attr(struct device_attribute *dev_attr)
65{
66 return container_of(dev_attr, struct gpio_sim_attribute, dev_attr);
67}
68
69static int gpio_sim_apply_pull(struct gpio_sim_chip *chip,
70 unsigned int offset, int value)
71{
72 int irq, irq_type, ret;
73
74 guard(mutex)(&chip->lock);
75
76 if (test_bit(offset, chip->request_map) &&
77 test_bit(offset, chip->direction_map)) {
78 if (value == !!test_bit(offset, chip->value_map))
79 goto set_pull;
80
81 /*
82 * This is fine - it just means, nobody is listening
83 * for interrupts on this line, otherwise
84 * irq_create_mapping() would have been called from
85 * the to_irq() callback.
86 */
87 irq = irq_find_mapping(chip->irq_sim, offset);
88 if (!irq)
89 goto set_value;
90
91 irq_type = irq_get_trigger_type(irq);
92
93 if ((value && (irq_type & IRQ_TYPE_EDGE_RISING)) ||
94 (!value && (irq_type & IRQ_TYPE_EDGE_FALLING))) {
95 ret = irq_set_irqchip_state(irq, IRQCHIP_STATE_PENDING,
96 true);
97 if (ret)
98 goto set_pull;
99 }
100 }
101
102set_value:
103 /* Change the value unless we're actively driving the line. */
104 if (!test_bit(offset, chip->request_map) ||
105 test_bit(offset, chip->direction_map))
106 __assign_bit(offset, chip->value_map, value);
107
108set_pull:
109 __assign_bit(offset, chip->pull_map, value);
110 return 0;
111}
112
113static int gpio_sim_get(struct gpio_chip *gc, unsigned int offset)
114{
115 struct gpio_sim_chip *chip = gpiochip_get_data(gc);
116
117 guard(mutex)(&chip->lock);
118
119 return !!test_bit(offset, chip->value_map);
120}
121
122static void gpio_sim_set(struct gpio_chip *gc, unsigned int offset, int value)
123{
124 struct gpio_sim_chip *chip = gpiochip_get_data(gc);
125
126 scoped_guard(mutex, &chip->lock)
127 __assign_bit(offset, chip->value_map, value);
128}
129
130static int gpio_sim_get_multiple(struct gpio_chip *gc,
131 unsigned long *mask, unsigned long *bits)
132{
133 struct gpio_sim_chip *chip = gpiochip_get_data(gc);
134
135 scoped_guard(mutex, &chip->lock)
136 bitmap_replace(bits, bits, chip->value_map, mask, gc->ngpio);
137
138 return 0;
139}
140
141static void gpio_sim_set_multiple(struct gpio_chip *gc,
142 unsigned long *mask, unsigned long *bits)
143{
144 struct gpio_sim_chip *chip = gpiochip_get_data(gc);
145
146 scoped_guard(mutex, &chip->lock)
147 bitmap_replace(chip->value_map, chip->value_map, bits, mask,
148 gc->ngpio);
149}
150
151static int gpio_sim_direction_output(struct gpio_chip *gc,
152 unsigned int offset, int value)
153{
154 struct gpio_sim_chip *chip = gpiochip_get_data(gc);
155
156 scoped_guard(mutex, &chip->lock) {
157 __clear_bit(offset, chip->direction_map);
158 __assign_bit(offset, chip->value_map, value);
159 }
160
161 return 0;
162}
163
164static int gpio_sim_direction_input(struct gpio_chip *gc, unsigned int offset)
165{
166 struct gpio_sim_chip *chip = gpiochip_get_data(gc);
167
168 scoped_guard(mutex, &chip->lock)
169 __set_bit(offset, chip->direction_map);
170
171 return 0;
172}
173
174static int gpio_sim_get_direction(struct gpio_chip *gc, unsigned int offset)
175{
176 struct gpio_sim_chip *chip = gpiochip_get_data(gc);
177 int direction;
178
179 scoped_guard(mutex, &chip->lock)
180 direction = !!test_bit(offset, chip->direction_map);
181
182 return direction ? GPIO_LINE_DIRECTION_IN : GPIO_LINE_DIRECTION_OUT;
183}
184
185static int gpio_sim_set_config(struct gpio_chip *gc, unsigned int offset,
186 unsigned long config)
187{
188 struct gpio_sim_chip *chip = gpiochip_get_data(gc);
189
190 switch (pinconf_to_config_param(config)) {
191 case PIN_CONFIG_BIAS_PULL_UP:
192 return gpio_sim_apply_pull(chip, offset, 1);
193 case PIN_CONFIG_BIAS_PULL_DOWN:
194 return gpio_sim_apply_pull(chip, offset, 0);
195 default:
196 break;
197 }
198
199 return -ENOTSUPP;
200}
201
202static int gpio_sim_to_irq(struct gpio_chip *gc, unsigned int offset)
203{
204 struct gpio_sim_chip *chip = gpiochip_get_data(gc);
205
206 return irq_create_mapping(chip->irq_sim, offset);
207}
208
209static int gpio_sim_request(struct gpio_chip *gc, unsigned int offset)
210{
211 struct gpio_sim_chip *chip = gpiochip_get_data(gc);
212
213 scoped_guard(mutex, &chip->lock)
214 __set_bit(offset, chip->request_map);
215
216 return 0;
217}
218
219static void gpio_sim_free(struct gpio_chip *gc, unsigned int offset)
220{
221 struct gpio_sim_chip *chip = gpiochip_get_data(gc);
222
223 scoped_guard(mutex, &chip->lock) {
224 __assign_bit(offset, chip->value_map,
225 !!test_bit(offset, chip->pull_map));
226 __clear_bit(offset, chip->request_map);
227 }
228}
229
230static void gpio_sim_dbg_show(struct seq_file *seq, struct gpio_chip *gc)
231{
232 struct gpio_sim_chip *chip = gpiochip_get_data(gc);
233 const char *label;
234 int i;
235
236 guard(mutex)(&chip->lock);
237
238 for_each_hwgpio(gc, i, label)
239 seq_printf(seq, " gpio-%-3d (%s) %s,%s\n",
240 gc->base + i,
241 label ?: "<unused>",
242 test_bit(i, chip->direction_map) ? "input" :
243 test_bit(i, chip->value_map) ? "output-high" :
244 "output-low",
245 test_bit(i, chip->pull_map) ? "pull-up" :
246 "pull-down");
247}
248
249static ssize_t gpio_sim_sysfs_val_show(struct device *dev,
250 struct device_attribute *attr, char *buf)
251{
252 struct gpio_sim_attribute *line_attr = to_gpio_sim_attr(attr);
253 struct gpio_sim_chip *chip = dev_get_drvdata(dev);
254 int val;
255
256 scoped_guard(mutex, &chip->lock)
257 val = !!test_bit(line_attr->offset, chip->value_map);
258
259 return sysfs_emit(buf, "%d\n", val);
260}
261
262static ssize_t gpio_sim_sysfs_val_store(struct device *dev,
263 struct device_attribute *attr,
264 const char *buf, size_t count)
265{
266 /*
267 * Not assigning this function will result in write() returning -EIO
268 * which is confusing. Return -EPERM explicitly.
269 */
270 return -EPERM;
271}
272
273static const char *const gpio_sim_sysfs_pull_strings[] = {
274 [0] = "pull-down",
275 [1] = "pull-up",
276};
277
278static ssize_t gpio_sim_sysfs_pull_show(struct device *dev,
279 struct device_attribute *attr,
280 char *buf)
281{
282 struct gpio_sim_attribute *line_attr = to_gpio_sim_attr(attr);
283 struct gpio_sim_chip *chip = dev_get_drvdata(dev);
284 int pull;
285
286 scoped_guard(mutex, &chip->lock)
287 pull = !!test_bit(line_attr->offset, chip->pull_map);
288
289 return sysfs_emit(buf, "%s\n", gpio_sim_sysfs_pull_strings[pull]);
290}
291
292static ssize_t gpio_sim_sysfs_pull_store(struct device *dev,
293 struct device_attribute *attr,
294 const char *buf, size_t len)
295{
296 struct gpio_sim_attribute *line_attr = to_gpio_sim_attr(attr);
297 struct gpio_sim_chip *chip = dev_get_drvdata(dev);
298 int ret, pull;
299
300 pull = sysfs_match_string(gpio_sim_sysfs_pull_strings, buf);
301 if (pull < 0)
302 return pull;
303
304 ret = gpio_sim_apply_pull(chip, line_attr->offset, pull);
305 if (ret)
306 return ret;
307
308 return len;
309}
310
311static void gpio_sim_mutex_destroy(void *data)
312{
313 struct mutex *lock = data;
314
315 mutex_destroy(lock);
316}
317
318static void gpio_sim_put_device(void *data)
319{
320 struct device *dev = data;
321
322 put_device(dev);
323}
324
325static void gpio_sim_dispose_mappings(void *data)
326{
327 struct gpio_sim_chip *chip = data;
328 unsigned int i;
329
330 for (i = 0; i < chip->gc.ngpio; i++)
331 irq_dispose_mapping(irq_find_mapping(chip->irq_sim, i));
332}
333
334static void gpio_sim_sysfs_remove(void *data)
335{
336 struct gpio_sim_chip *chip = data;
337
338 sysfs_remove_groups(&chip->dev->kobj, chip->attr_groups);
339}
340
341static int gpio_sim_setup_sysfs(struct gpio_sim_chip *chip)
342{
343 struct device_attribute *val_dev_attr, *pull_dev_attr;
344 struct gpio_sim_attribute *val_attr, *pull_attr;
345 unsigned int num_lines = chip->gc.ngpio;
346 struct device *dev = chip->gc.parent;
347 struct attribute_group *attr_group;
348 struct attribute **attrs;
349 int i, ret;
350
351 chip->attr_groups = devm_kcalloc(dev, sizeof(*chip->attr_groups),
352 num_lines + 1, GFP_KERNEL);
353 if (!chip->attr_groups)
354 return -ENOMEM;
355
356 for (i = 0; i < num_lines; i++) {
357 attr_group = devm_kzalloc(dev, sizeof(*attr_group), GFP_KERNEL);
358 attrs = devm_kcalloc(dev, GPIO_SIM_NUM_ATTRS, sizeof(*attrs),
359 GFP_KERNEL);
360 val_attr = devm_kzalloc(dev, sizeof(*val_attr), GFP_KERNEL);
361 pull_attr = devm_kzalloc(dev, sizeof(*pull_attr), GFP_KERNEL);
362 if (!attr_group || !attrs || !val_attr || !pull_attr)
363 return -ENOMEM;
364
365 attr_group->name = devm_kasprintf(dev, GFP_KERNEL,
366 "sim_gpio%u", i);
367 if (!attr_group->name)
368 return -ENOMEM;
369
370 val_attr->offset = pull_attr->offset = i;
371
372 val_dev_attr = &val_attr->dev_attr;
373 pull_dev_attr = &pull_attr->dev_attr;
374
375 sysfs_attr_init(&val_dev_attr->attr);
376 sysfs_attr_init(&pull_dev_attr->attr);
377
378 val_dev_attr->attr.name = "value";
379 pull_dev_attr->attr.name = "pull";
380
381 val_dev_attr->attr.mode = pull_dev_attr->attr.mode = 0644;
382
383 val_dev_attr->show = gpio_sim_sysfs_val_show;
384 val_dev_attr->store = gpio_sim_sysfs_val_store;
385 pull_dev_attr->show = gpio_sim_sysfs_pull_show;
386 pull_dev_attr->store = gpio_sim_sysfs_pull_store;
387
388 attrs[0] = &val_dev_attr->attr;
389 attrs[1] = &pull_dev_attr->attr;
390
391 attr_group->attrs = attrs;
392 chip->attr_groups[i] = attr_group;
393 }
394
395 ret = sysfs_create_groups(&chip->dev->kobj, chip->attr_groups);
396 if (ret)
397 return ret;
398
399 return devm_add_action_or_reset(dev, gpio_sim_sysfs_remove, chip);
400}
401
402static int gpio_sim_dev_match_fwnode(struct device *dev, void *data)
403{
404 return device_match_fwnode(dev, data);
405}
406
407static int gpio_sim_add_bank(struct fwnode_handle *swnode, struct device *dev)
408{
409 struct gpio_sim_chip *chip;
410 struct gpio_chip *gc;
411 const char *label;
412 u32 num_lines;
413 int ret;
414
415 ret = fwnode_property_read_u32(swnode, "ngpios", &num_lines);
416 if (ret)
417 return ret;
418
419 if (num_lines > GPIO_SIM_NGPIO_MAX)
420 return -ERANGE;
421
422 ret = fwnode_property_read_string(swnode, "gpio-sim,label", &label);
423 if (ret) {
424 label = devm_kasprintf(dev, GFP_KERNEL, "%s:%pfwP",
425 dev_name(dev), swnode);
426 if (!label)
427 return -ENOMEM;
428 }
429
430 chip = devm_kzalloc(dev, sizeof(*chip), GFP_KERNEL);
431 if (!chip)
432 return -ENOMEM;
433
434 chip->request_map = devm_bitmap_zalloc(dev, num_lines, GFP_KERNEL);
435 if (!chip->request_map)
436 return -ENOMEM;
437
438 chip->direction_map = devm_bitmap_alloc(dev, num_lines, GFP_KERNEL);
439 if (!chip->direction_map)
440 return -ENOMEM;
441
442 /* Default to input mode. */
443 bitmap_fill(chip->direction_map, num_lines);
444
445 chip->value_map = devm_bitmap_zalloc(dev, num_lines, GFP_KERNEL);
446 if (!chip->value_map)
447 return -ENOMEM;
448
449 chip->pull_map = devm_bitmap_zalloc(dev, num_lines, GFP_KERNEL);
450 if (!chip->pull_map)
451 return -ENOMEM;
452
453 chip->irq_sim = devm_irq_domain_create_sim(dev, swnode, num_lines);
454 if (IS_ERR(chip->irq_sim))
455 return PTR_ERR(chip->irq_sim);
456
457 ret = devm_add_action_or_reset(dev, gpio_sim_dispose_mappings, chip);
458 if (ret)
459 return ret;
460
461 mutex_init(&chip->lock);
462 ret = devm_add_action_or_reset(dev, gpio_sim_mutex_destroy,
463 &chip->lock);
464 if (ret)
465 return ret;
466
467 gc = &chip->gc;
468 gc->base = -1;
469 gc->ngpio = num_lines;
470 gc->label = label;
471 gc->owner = THIS_MODULE;
472 gc->parent = dev;
473 gc->fwnode = swnode;
474 gc->get = gpio_sim_get;
475 gc->set = gpio_sim_set;
476 gc->get_multiple = gpio_sim_get_multiple;
477 gc->set_multiple = gpio_sim_set_multiple;
478 gc->direction_output = gpio_sim_direction_output;
479 gc->direction_input = gpio_sim_direction_input;
480 gc->get_direction = gpio_sim_get_direction;
481 gc->set_config = gpio_sim_set_config;
482 gc->to_irq = gpio_sim_to_irq;
483 gc->request = gpio_sim_request;
484 gc->free = gpio_sim_free;
485 gc->dbg_show = PTR_IF(IS_ENABLED(CONFIG_DEBUG_FS), gpio_sim_dbg_show);
486 gc->can_sleep = true;
487
488 ret = devm_gpiochip_add_data(dev, gc, chip);
489 if (ret)
490 return ret;
491
492 chip->dev = device_find_child(dev, swnode, gpio_sim_dev_match_fwnode);
493 if (!chip->dev)
494 return -ENODEV;
495
496 ret = devm_add_action_or_reset(dev, gpio_sim_put_device, chip->dev);
497 if (ret)
498 return ret;
499
500 /* Used by sysfs callbacks. */
501 dev_set_drvdata(chip->dev, chip);
502
503 return gpio_sim_setup_sysfs(chip);
504}
505
506static int gpio_sim_probe(struct platform_device *pdev)
507{
508 struct device *dev = &pdev->dev;
509 struct fwnode_handle *swnode;
510 int ret;
511
512 device_for_each_child_node(dev, swnode) {
513 ret = gpio_sim_add_bank(swnode, dev);
514 if (ret) {
515 fwnode_handle_put(swnode);
516 return ret;
517 }
518 }
519
520 return 0;
521}
522
523static const struct of_device_id gpio_sim_of_match[] = {
524 { .compatible = "gpio-simulator" },
525 { }
526};
527MODULE_DEVICE_TABLE(of, gpio_sim_of_match);
528
529static struct platform_driver gpio_sim_driver = {
530 .driver = {
531 .name = "gpio-sim",
532 .of_match_table = gpio_sim_of_match,
533 },
534 .probe = gpio_sim_probe,
535};
536
537struct gpio_sim_device {
538 struct config_group group;
539
540 /*
541 * If pdev is NULL, the device is 'pending' (waiting for configuration).
542 * Once the pointer is assigned, the device has been created and the
543 * item is 'live'.
544 */
545 struct platform_device *pdev;
546 int id;
547
548 /*
549 * Each configfs filesystem operation is protected with the subsystem
550 * mutex. Each separate attribute is protected with the buffer mutex.
551 * This structure however can be modified by callbacks of different
552 * attributes so we need another lock.
553 *
554 * We use this lock for protecting all data structures owned by this
555 * object too.
556 */
557 struct mutex lock;
558
559 /*
560 * This is used to synchronously wait for the driver's probe to complete
561 * and notify the user-space about any errors.
562 */
563 struct notifier_block bus_notifier;
564 struct completion probe_completion;
565 bool driver_bound;
566
567 struct gpiod_hog *hogs;
568
569 struct list_head bank_list;
570};
571
572/* This is called with dev->lock already taken. */
573static int gpio_sim_bus_notifier_call(struct notifier_block *nb,
574 unsigned long action, void *data)
575{
576 struct gpio_sim_device *simdev = container_of(nb,
577 struct gpio_sim_device,
578 bus_notifier);
579 struct device *dev = data;
580 char devname[32];
581
582 snprintf(devname, sizeof(devname), "gpio-sim.%u", simdev->id);
583
584 if (strcmp(dev_name(dev), devname) == 0) {
585 if (action == BUS_NOTIFY_BOUND_DRIVER)
586 simdev->driver_bound = true;
587 else if (action == BUS_NOTIFY_DRIVER_NOT_BOUND)
588 simdev->driver_bound = false;
589 else
590 return NOTIFY_DONE;
591
592 complete(&simdev->probe_completion);
593 return NOTIFY_OK;
594 }
595
596 return NOTIFY_DONE;
597}
598
599static struct gpio_sim_device *to_gpio_sim_device(struct config_item *item)
600{
601 struct config_group *group = to_config_group(item);
602
603 return container_of(group, struct gpio_sim_device, group);
604}
605
606struct gpio_sim_bank {
607 struct config_group group;
608
609 /*
610 * We could have used the ci_parent field of the config_item but
611 * configfs is stupid and calls the item's release callback after
612 * already having cleared the parent pointer even though the parent
613 * is guaranteed to survive the child...
614 *
615 * So we need to store the pointer to the parent struct here. We can
616 * dereference it anywhere we need with no checks and no locking as
617 * it's guaranteed to survive the children and protected by configfs
618 * locks.
619 *
620 * Same for other structures.
621 */
622 struct gpio_sim_device *parent;
623 struct list_head siblings;
624
625 char *label;
626 unsigned int num_lines;
627
628 struct list_head line_list;
629
630 struct fwnode_handle *swnode;
631};
632
633static struct gpio_sim_bank *to_gpio_sim_bank(struct config_item *item)
634{
635 struct config_group *group = to_config_group(item);
636
637 return container_of(group, struct gpio_sim_bank, group);
638}
639
640static bool gpio_sim_bank_has_label(struct gpio_sim_bank *bank)
641{
642 return bank->label && *bank->label;
643}
644
645static struct gpio_sim_device *
646gpio_sim_bank_get_device(struct gpio_sim_bank *bank)
647{
648 return bank->parent;
649}
650
651struct gpio_sim_hog;
652
653struct gpio_sim_line {
654 struct config_group group;
655
656 struct gpio_sim_bank *parent;
657 struct list_head siblings;
658
659 unsigned int offset;
660 char *name;
661
662 /* There can only be one hog per line. */
663 struct gpio_sim_hog *hog;
664};
665
666static struct gpio_sim_line *to_gpio_sim_line(struct config_item *item)
667{
668 struct config_group *group = to_config_group(item);
669
670 return container_of(group, struct gpio_sim_line, group);
671}
672
673static struct gpio_sim_device *
674gpio_sim_line_get_device(struct gpio_sim_line *line)
675{
676 struct gpio_sim_bank *bank = line->parent;
677
678 return gpio_sim_bank_get_device(bank);
679}
680
681struct gpio_sim_hog {
682 struct config_item item;
683 struct gpio_sim_line *parent;
684
685 char *name;
686 int dir;
687};
688
689static struct gpio_sim_hog *to_gpio_sim_hog(struct config_item *item)
690{
691 return container_of(item, struct gpio_sim_hog, item);
692}
693
694static struct gpio_sim_device *gpio_sim_hog_get_device(struct gpio_sim_hog *hog)
695{
696 struct gpio_sim_line *line = hog->parent;
697
698 return gpio_sim_line_get_device(line);
699}
700
701static bool gpio_sim_device_is_live(struct gpio_sim_device *dev)
702{
703 lockdep_assert_held(&dev->lock);
704
705 return !!dev->pdev;
706}
707
708static char *gpio_sim_strdup_trimmed(const char *str, size_t count)
709{
710 char *trimmed;
711
712 trimmed = kstrndup(skip_spaces(str), count, GFP_KERNEL);
713 if (!trimmed)
714 return NULL;
715
716 return strim(trimmed);
717}
718
719static ssize_t gpio_sim_device_config_dev_name_show(struct config_item *item,
720 char *page)
721{
722 struct gpio_sim_device *dev = to_gpio_sim_device(item);
723 struct platform_device *pdev;
724
725 guard(mutex)(&dev->lock);
726
727 pdev = dev->pdev;
728 if (pdev)
729 return sprintf(page, "%s\n", dev_name(&pdev->dev));
730
731 return sprintf(page, "gpio-sim.%d\n", dev->id);
732}
733
734CONFIGFS_ATTR_RO(gpio_sim_device_config_, dev_name);
735
736static ssize_t
737gpio_sim_device_config_live_show(struct config_item *item, char *page)
738{
739 struct gpio_sim_device *dev = to_gpio_sim_device(item);
740 bool live;
741
742 scoped_guard(mutex, &dev->lock)
743 live = gpio_sim_device_is_live(dev);
744
745 return sprintf(page, "%c\n", live ? '1' : '0');
746}
747
748static unsigned int gpio_sim_get_line_names_size(struct gpio_sim_bank *bank)
749{
750 struct gpio_sim_line *line;
751 unsigned int size = 0;
752
753 list_for_each_entry(line, &bank->line_list, siblings) {
754 if (!line->name || (line->offset >= bank->num_lines))
755 continue;
756
757 size = max(size, line->offset + 1);
758 }
759
760 return size;
761}
762
763static void
764gpio_sim_set_line_names(struct gpio_sim_bank *bank, char **line_names)
765{
766 struct gpio_sim_line *line;
767
768 list_for_each_entry(line, &bank->line_list, siblings) {
769 if (!line->name || (line->offset >= bank->num_lines))
770 continue;
771
772 line_names[line->offset] = line->name;
773 }
774}
775
776static void gpio_sim_remove_hogs(struct gpio_sim_device *dev)
777{
778 struct gpiod_hog *hog;
779
780 if (!dev->hogs)
781 return;
782
783 gpiod_remove_hogs(dev->hogs);
784
785 for (hog = dev->hogs; hog->chip_label; hog++) {
786 kfree(hog->chip_label);
787 kfree(hog->line_name);
788 }
789
790 kfree(dev->hogs);
791 dev->hogs = NULL;
792}
793
794static int gpio_sim_add_hogs(struct gpio_sim_device *dev)
795{
796 unsigned int num_hogs = 0, idx = 0;
797 struct gpio_sim_bank *bank;
798 struct gpio_sim_line *line;
799 struct gpiod_hog *hog;
800
801 list_for_each_entry(bank, &dev->bank_list, siblings) {
802 list_for_each_entry(line, &bank->line_list, siblings) {
803 if (line->offset >= bank->num_lines)
804 continue;
805
806 if (line->hog)
807 num_hogs++;
808 }
809 }
810
811 if (!num_hogs)
812 return 0;
813
814 /* Allocate one more for the sentinel. */
815 dev->hogs = kcalloc(num_hogs + 1, sizeof(*dev->hogs), GFP_KERNEL);
816 if (!dev->hogs)
817 return -ENOMEM;
818
819 list_for_each_entry(bank, &dev->bank_list, siblings) {
820 list_for_each_entry(line, &bank->line_list, siblings) {
821 if (line->offset >= bank->num_lines)
822 continue;
823
824 if (!line->hog)
825 continue;
826
827 hog = &dev->hogs[idx++];
828
829 /*
830 * We need to make this string manually because at this
831 * point the device doesn't exist yet and so dev_name()
832 * is not available.
833 */
834 if (gpio_sim_bank_has_label(bank))
835 hog->chip_label = kstrdup(bank->label,
836 GFP_KERNEL);
837 else
838 hog->chip_label = kasprintf(GFP_KERNEL,
839 "gpio-sim.%u:%pfwP",
840 dev->id,
841 bank->swnode);
842 if (!hog->chip_label) {
843 gpio_sim_remove_hogs(dev);
844 return -ENOMEM;
845 }
846
847 /*
848 * We need to duplicate this because the hog config
849 * item can be removed at any time (and we can't block
850 * it) and gpiolib doesn't make a deep copy of the hog
851 * data.
852 */
853 if (line->hog->name) {
854 hog->line_name = kstrdup(line->hog->name,
855 GFP_KERNEL);
856 if (!hog->line_name) {
857 gpio_sim_remove_hogs(dev);
858 return -ENOMEM;
859 }
860 }
861
862 hog->chip_hwnum = line->offset;
863 hog->dflags = line->hog->dir;
864 }
865 }
866
867 gpiod_add_hogs(dev->hogs);
868
869 return 0;
870}
871
872static struct fwnode_handle *
873gpio_sim_make_bank_swnode(struct gpio_sim_bank *bank,
874 struct fwnode_handle *parent)
875{
876 struct property_entry properties[GPIO_SIM_PROP_MAX];
877 unsigned int prop_idx = 0, line_names_size;
878 char **line_names __free(kfree) = NULL;
879
880 memset(properties, 0, sizeof(properties));
881
882 properties[prop_idx++] = PROPERTY_ENTRY_U32("ngpios", bank->num_lines);
883
884 if (gpio_sim_bank_has_label(bank))
885 properties[prop_idx++] = PROPERTY_ENTRY_STRING("gpio-sim,label",
886 bank->label);
887
888 line_names_size = gpio_sim_get_line_names_size(bank);
889 if (line_names_size) {
890 line_names = kcalloc(line_names_size, sizeof(*line_names),
891 GFP_KERNEL);
892 if (!line_names)
893 return ERR_PTR(-ENOMEM);
894
895 gpio_sim_set_line_names(bank, line_names);
896
897 properties[prop_idx++] = PROPERTY_ENTRY_STRING_ARRAY_LEN(
898 "gpio-line-names",
899 line_names, line_names_size);
900 }
901
902 return fwnode_create_software_node(properties, parent);
903}
904
905static void gpio_sim_remove_swnode_recursive(struct fwnode_handle *swnode)
906{
907 struct fwnode_handle *child;
908
909 fwnode_for_each_child_node(swnode, child)
910 fwnode_remove_software_node(child);
911
912 fwnode_remove_software_node(swnode);
913}
914
915static bool gpio_sim_bank_labels_non_unique(struct gpio_sim_device *dev)
916{
917 struct gpio_sim_bank *this, *pos;
918
919 list_for_each_entry(this, &dev->bank_list, siblings) {
920 list_for_each_entry(pos, &dev->bank_list, siblings) {
921 if (this == pos || (!this->label || !pos->label))
922 continue;
923
924 if (strcmp(this->label, pos->label) == 0)
925 return true;
926 }
927 }
928
929 return false;
930}
931
932static int gpio_sim_device_activate(struct gpio_sim_device *dev)
933{
934 struct platform_device_info pdevinfo;
935 struct fwnode_handle *swnode;
936 struct platform_device *pdev;
937 struct gpio_sim_bank *bank;
938 int ret;
939
940 lockdep_assert_held(&dev->lock);
941
942 if (list_empty(&dev->bank_list))
943 return -ENODATA;
944
945 /*
946 * Non-unique GPIO device labels are a corner-case we don't support
947 * as it would interfere with machine hogging mechanism and has little
948 * use in real life.
949 */
950 if (gpio_sim_bank_labels_non_unique(dev))
951 return -EINVAL;
952
953 memset(&pdevinfo, 0, sizeof(pdevinfo));
954
955 swnode = fwnode_create_software_node(NULL, NULL);
956 if (IS_ERR(swnode))
957 return PTR_ERR(swnode);
958
959 list_for_each_entry(bank, &dev->bank_list, siblings) {
960 bank->swnode = gpio_sim_make_bank_swnode(bank, swnode);
961 if (IS_ERR(bank->swnode)) {
962 ret = PTR_ERR(bank->swnode);
963 gpio_sim_remove_swnode_recursive(swnode);
964 return ret;
965 }
966 }
967
968 ret = gpio_sim_add_hogs(dev);
969 if (ret) {
970 gpio_sim_remove_swnode_recursive(swnode);
971 return ret;
972 }
973
974 pdevinfo.name = "gpio-sim";
975 pdevinfo.fwnode = swnode;
976 pdevinfo.id = dev->id;
977
978 reinit_completion(&dev->probe_completion);
979 dev->driver_bound = false;
980 bus_register_notifier(&platform_bus_type, &dev->bus_notifier);
981
982 pdev = platform_device_register_full(&pdevinfo);
983 if (IS_ERR(pdev)) {
984 bus_unregister_notifier(&platform_bus_type, &dev->bus_notifier);
985 gpio_sim_remove_hogs(dev);
986 gpio_sim_remove_swnode_recursive(swnode);
987 return PTR_ERR(pdev);
988 }
989
990 wait_for_completion(&dev->probe_completion);
991 bus_unregister_notifier(&platform_bus_type, &dev->bus_notifier);
992
993 if (!dev->driver_bound) {
994 /* Probe failed, check kernel log. */
995 platform_device_unregister(pdev);
996 gpio_sim_remove_hogs(dev);
997 gpio_sim_remove_swnode_recursive(swnode);
998 return -ENXIO;
999 }
1000
1001 dev->pdev = pdev;
1002
1003 return 0;
1004}
1005
1006static void gpio_sim_device_deactivate(struct gpio_sim_device *dev)
1007{
1008 struct fwnode_handle *swnode;
1009
1010 lockdep_assert_held(&dev->lock);
1011
1012 swnode = dev_fwnode(&dev->pdev->dev);
1013 platform_device_unregister(dev->pdev);
1014 gpio_sim_remove_hogs(dev);
1015 gpio_sim_remove_swnode_recursive(swnode);
1016 dev->pdev = NULL;
1017}
1018
1019static ssize_t
1020gpio_sim_device_config_live_store(struct config_item *item,
1021 const char *page, size_t count)
1022{
1023 struct gpio_sim_device *dev = to_gpio_sim_device(item);
1024 bool live;
1025 int ret;
1026
1027 ret = kstrtobool(page, &live);
1028 if (ret)
1029 return ret;
1030
1031 guard(mutex)(&dev->lock);
1032
1033 if (live == gpio_sim_device_is_live(dev))
1034 ret = -EPERM;
1035 else if (live)
1036 ret = gpio_sim_device_activate(dev);
1037 else
1038 gpio_sim_device_deactivate(dev);
1039
1040 return ret ?: count;
1041}
1042
1043CONFIGFS_ATTR(gpio_sim_device_config_, live);
1044
1045static struct configfs_attribute *gpio_sim_device_config_attrs[] = {
1046 &gpio_sim_device_config_attr_dev_name,
1047 &gpio_sim_device_config_attr_live,
1048 NULL
1049};
1050
1051struct gpio_sim_chip_name_ctx {
1052 struct fwnode_handle *swnode;
1053 char *page;
1054};
1055
1056static int gpio_sim_emit_chip_name(struct device *dev, void *data)
1057{
1058 struct gpio_sim_chip_name_ctx *ctx = data;
1059
1060 /* This would be the sysfs device exported in /sys/class/gpio. */
1061 if (dev->class)
1062 return 0;
1063
1064 if (device_match_fwnode(dev, ctx->swnode))
1065 return sprintf(ctx->page, "%s\n", dev_name(dev));
1066
1067 return 0;
1068}
1069
1070static ssize_t gpio_sim_bank_config_chip_name_show(struct config_item *item,
1071 char *page)
1072{
1073 struct gpio_sim_bank *bank = to_gpio_sim_bank(item);
1074 struct gpio_sim_device *dev = gpio_sim_bank_get_device(bank);
1075 struct gpio_sim_chip_name_ctx ctx = { bank->swnode, page };
1076
1077 guard(mutex)(&dev->lock);
1078
1079 if (gpio_sim_device_is_live(dev))
1080 return device_for_each_child(&dev->pdev->dev, &ctx,
1081 gpio_sim_emit_chip_name);
1082
1083 return sprintf(page, "none\n");
1084}
1085
1086CONFIGFS_ATTR_RO(gpio_sim_bank_config_, chip_name);
1087
1088static ssize_t
1089gpio_sim_bank_config_label_show(struct config_item *item, char *page)
1090{
1091 struct gpio_sim_bank *bank = to_gpio_sim_bank(item);
1092 struct gpio_sim_device *dev = gpio_sim_bank_get_device(bank);
1093
1094 guard(mutex)(&dev->lock);
1095
1096 return sprintf(page, "%s\n", bank->label ?: "");
1097}
1098
1099static ssize_t gpio_sim_bank_config_label_store(struct config_item *item,
1100 const char *page, size_t count)
1101{
1102 struct gpio_sim_bank *bank = to_gpio_sim_bank(item);
1103 struct gpio_sim_device *dev = gpio_sim_bank_get_device(bank);
1104 char *trimmed;
1105
1106 guard(mutex)(&dev->lock);
1107
1108 if (gpio_sim_device_is_live(dev))
1109 return -EBUSY;
1110
1111 trimmed = gpio_sim_strdup_trimmed(page, count);
1112 if (!trimmed)
1113 return -ENOMEM;
1114
1115 kfree(bank->label);
1116 bank->label = trimmed;
1117
1118 return count;
1119}
1120
1121CONFIGFS_ATTR(gpio_sim_bank_config_, label);
1122
1123static ssize_t
1124gpio_sim_bank_config_num_lines_show(struct config_item *item, char *page)
1125{
1126 struct gpio_sim_bank *bank = to_gpio_sim_bank(item);
1127 struct gpio_sim_device *dev = gpio_sim_bank_get_device(bank);
1128
1129 guard(mutex)(&dev->lock);
1130
1131 return sprintf(page, "%u\n", bank->num_lines);
1132}
1133
1134static ssize_t
1135gpio_sim_bank_config_num_lines_store(struct config_item *item,
1136 const char *page, size_t count)
1137{
1138 struct gpio_sim_bank *bank = to_gpio_sim_bank(item);
1139 struct gpio_sim_device *dev = gpio_sim_bank_get_device(bank);
1140 unsigned int num_lines;
1141 int ret;
1142
1143 ret = kstrtouint(page, 0, &num_lines);
1144 if (ret)
1145 return ret;
1146
1147 if (num_lines == 0)
1148 return -EINVAL;
1149
1150 guard(mutex)(&dev->lock);
1151
1152 if (gpio_sim_device_is_live(dev))
1153 return -EBUSY;
1154
1155 bank->num_lines = num_lines;
1156
1157 return count;
1158}
1159
1160CONFIGFS_ATTR(gpio_sim_bank_config_, num_lines);
1161
1162static struct configfs_attribute *gpio_sim_bank_config_attrs[] = {
1163 &gpio_sim_bank_config_attr_chip_name,
1164 &gpio_sim_bank_config_attr_label,
1165 &gpio_sim_bank_config_attr_num_lines,
1166 NULL
1167};
1168
1169static ssize_t
1170gpio_sim_line_config_name_show(struct config_item *item, char *page)
1171{
1172 struct gpio_sim_line *line = to_gpio_sim_line(item);
1173 struct gpio_sim_device *dev = gpio_sim_line_get_device(line);
1174
1175 guard(mutex)(&dev->lock);
1176
1177 return sprintf(page, "%s\n", line->name ?: "");
1178}
1179
1180static ssize_t gpio_sim_line_config_name_store(struct config_item *item,
1181 const char *page, size_t count)
1182{
1183 struct gpio_sim_line *line = to_gpio_sim_line(item);
1184 struct gpio_sim_device *dev = gpio_sim_line_get_device(line);
1185 char *trimmed;
1186
1187 guard(mutex)(&dev->lock);
1188
1189 if (gpio_sim_device_is_live(dev))
1190 return -EBUSY;
1191
1192 trimmed = gpio_sim_strdup_trimmed(page, count);
1193 if (!trimmed)
1194 return -ENOMEM;
1195
1196 kfree(line->name);
1197 line->name = trimmed;
1198
1199 return count;
1200}
1201
1202CONFIGFS_ATTR(gpio_sim_line_config_, name);
1203
1204static struct configfs_attribute *gpio_sim_line_config_attrs[] = {
1205 &gpio_sim_line_config_attr_name,
1206 NULL
1207};
1208
1209static ssize_t gpio_sim_hog_config_name_show(struct config_item *item,
1210 char *page)
1211{
1212 struct gpio_sim_hog *hog = to_gpio_sim_hog(item);
1213 struct gpio_sim_device *dev = gpio_sim_hog_get_device(hog);
1214
1215 guard(mutex)(&dev->lock);
1216
1217 return sprintf(page, "%s\n", hog->name ?: "");
1218}
1219
1220static ssize_t gpio_sim_hog_config_name_store(struct config_item *item,
1221 const char *page, size_t count)
1222{
1223 struct gpio_sim_hog *hog = to_gpio_sim_hog(item);
1224 struct gpio_sim_device *dev = gpio_sim_hog_get_device(hog);
1225 char *trimmed;
1226
1227 guard(mutex)(&dev->lock);
1228
1229 if (gpio_sim_device_is_live(dev))
1230 return -EBUSY;
1231
1232 trimmed = gpio_sim_strdup_trimmed(page, count);
1233 if (!trimmed)
1234 return -ENOMEM;
1235
1236 kfree(hog->name);
1237 hog->name = trimmed;
1238
1239 return count;
1240}
1241
1242CONFIGFS_ATTR(gpio_sim_hog_config_, name);
1243
1244static ssize_t gpio_sim_hog_config_direction_show(struct config_item *item,
1245 char *page)
1246{
1247 struct gpio_sim_hog *hog = to_gpio_sim_hog(item);
1248 struct gpio_sim_device *dev = gpio_sim_hog_get_device(hog);
1249 char *repr;
1250 int dir;
1251
1252 scoped_guard(mutex, &dev->lock)
1253 dir = hog->dir;
1254
1255 switch (dir) {
1256 case GPIOD_IN:
1257 repr = "input";
1258 break;
1259 case GPIOD_OUT_HIGH:
1260 repr = "output-high";
1261 break;
1262 case GPIOD_OUT_LOW:
1263 repr = "output-low";
1264 break;
1265 default:
1266 /* This would be a programmer bug. */
1267 WARN(1, "Unexpected hog direction value: %d", dir);
1268 return -EINVAL;
1269 }
1270
1271 return sprintf(page, "%s\n", repr);
1272}
1273
1274static ssize_t
1275gpio_sim_hog_config_direction_store(struct config_item *item,
1276 const char *page, size_t count)
1277{
1278 struct gpio_sim_hog *hog = to_gpio_sim_hog(item);
1279 struct gpio_sim_device *dev = gpio_sim_hog_get_device(hog);
1280 int dir;
1281
1282 guard(mutex)(&dev->lock);
1283
1284 if (gpio_sim_device_is_live(dev))
1285 return -EBUSY;
1286
1287 if (sysfs_streq(page, "input"))
1288 dir = GPIOD_IN;
1289 else if (sysfs_streq(page, "output-high"))
1290 dir = GPIOD_OUT_HIGH;
1291 else if (sysfs_streq(page, "output-low"))
1292 dir = GPIOD_OUT_LOW;
1293 else
1294 return -EINVAL;
1295
1296 hog->dir = dir;
1297
1298 return count;
1299}
1300
1301CONFIGFS_ATTR(gpio_sim_hog_config_, direction);
1302
1303static struct configfs_attribute *gpio_sim_hog_config_attrs[] = {
1304 &gpio_sim_hog_config_attr_name,
1305 &gpio_sim_hog_config_attr_direction,
1306 NULL
1307};
1308
1309static void gpio_sim_hog_config_item_release(struct config_item *item)
1310{
1311 struct gpio_sim_hog *hog = to_gpio_sim_hog(item);
1312 struct gpio_sim_line *line = hog->parent;
1313 struct gpio_sim_device *dev = gpio_sim_hog_get_device(hog);
1314
1315 scoped_guard(mutex, &dev->lock)
1316 line->hog = NULL;
1317
1318 kfree(hog->name);
1319 kfree(hog);
1320}
1321
1322static struct configfs_item_operations gpio_sim_hog_config_item_ops = {
1323 .release = gpio_sim_hog_config_item_release,
1324};
1325
1326static const struct config_item_type gpio_sim_hog_config_type = {
1327 .ct_item_ops = &gpio_sim_hog_config_item_ops,
1328 .ct_attrs = gpio_sim_hog_config_attrs,
1329 .ct_owner = THIS_MODULE,
1330};
1331
1332static struct config_item *
1333gpio_sim_line_config_make_hog_item(struct config_group *group, const char *name)
1334{
1335 struct gpio_sim_line *line = to_gpio_sim_line(&group->cg_item);
1336 struct gpio_sim_device *dev = gpio_sim_line_get_device(line);
1337 struct gpio_sim_hog *hog;
1338
1339 if (strcmp(name, "hog") != 0)
1340 return ERR_PTR(-EINVAL);
1341
1342 guard(mutex)(&dev->lock);
1343
1344 hog = kzalloc(sizeof(*hog), GFP_KERNEL);
1345 if (!hog)
1346 return ERR_PTR(-ENOMEM);
1347
1348 config_item_init_type_name(&hog->item, name,
1349 &gpio_sim_hog_config_type);
1350
1351 hog->dir = GPIOD_IN;
1352 hog->name = NULL;
1353 hog->parent = line;
1354 line->hog = hog;
1355
1356 return &hog->item;
1357}
1358
1359static void gpio_sim_line_config_group_release(struct config_item *item)
1360{
1361 struct gpio_sim_line *line = to_gpio_sim_line(item);
1362 struct gpio_sim_device *dev = gpio_sim_line_get_device(line);
1363
1364 scoped_guard(mutex, &dev->lock)
1365 list_del(&line->siblings);
1366
1367 kfree(line->name);
1368 kfree(line);
1369}
1370
1371static struct configfs_item_operations gpio_sim_line_config_item_ops = {
1372 .release = gpio_sim_line_config_group_release,
1373};
1374
1375static struct configfs_group_operations gpio_sim_line_config_group_ops = {
1376 .make_item = gpio_sim_line_config_make_hog_item,
1377};
1378
1379static const struct config_item_type gpio_sim_line_config_type = {
1380 .ct_item_ops = &gpio_sim_line_config_item_ops,
1381 .ct_group_ops = &gpio_sim_line_config_group_ops,
1382 .ct_attrs = gpio_sim_line_config_attrs,
1383 .ct_owner = THIS_MODULE,
1384};
1385
1386static struct config_group *
1387gpio_sim_bank_config_make_line_group(struct config_group *group,
1388 const char *name)
1389{
1390 struct gpio_sim_bank *bank = to_gpio_sim_bank(&group->cg_item);
1391 struct gpio_sim_device *dev = gpio_sim_bank_get_device(bank);
1392 struct gpio_sim_line *line;
1393 unsigned int offset;
1394 int ret, nchar;
1395
1396 ret = sscanf(name, "line%u%n", &offset, &nchar);
1397 if (ret != 1 || nchar != strlen(name))
1398 return ERR_PTR(-EINVAL);
1399
1400 guard(mutex)(&dev->lock);
1401
1402 if (gpio_sim_device_is_live(dev))
1403 return ERR_PTR(-EBUSY);
1404
1405 line = kzalloc(sizeof(*line), GFP_KERNEL);
1406 if (!line)
1407 return ERR_PTR(-ENOMEM);
1408
1409 config_group_init_type_name(&line->group, name,
1410 &gpio_sim_line_config_type);
1411
1412 line->parent = bank;
1413 line->offset = offset;
1414 list_add_tail(&line->siblings, &bank->line_list);
1415
1416 return &line->group;
1417}
1418
1419static void gpio_sim_bank_config_group_release(struct config_item *item)
1420{
1421 struct gpio_sim_bank *bank = to_gpio_sim_bank(item);
1422 struct gpio_sim_device *dev = gpio_sim_bank_get_device(bank);
1423
1424 scoped_guard(mutex, &dev->lock)
1425 list_del(&bank->siblings);
1426
1427 kfree(bank->label);
1428 kfree(bank);
1429}
1430
1431static struct configfs_item_operations gpio_sim_bank_config_item_ops = {
1432 .release = gpio_sim_bank_config_group_release,
1433};
1434
1435static struct configfs_group_operations gpio_sim_bank_config_group_ops = {
1436 .make_group = gpio_sim_bank_config_make_line_group,
1437};
1438
1439static const struct config_item_type gpio_sim_bank_config_group_type = {
1440 .ct_item_ops = &gpio_sim_bank_config_item_ops,
1441 .ct_group_ops = &gpio_sim_bank_config_group_ops,
1442 .ct_attrs = gpio_sim_bank_config_attrs,
1443 .ct_owner = THIS_MODULE,
1444};
1445
1446static struct config_group *
1447gpio_sim_device_config_make_bank_group(struct config_group *group,
1448 const char *name)
1449{
1450 struct gpio_sim_device *dev = to_gpio_sim_device(&group->cg_item);
1451 struct gpio_sim_bank *bank;
1452
1453 guard(mutex)(&dev->lock);
1454
1455 if (gpio_sim_device_is_live(dev))
1456 return ERR_PTR(-EBUSY);
1457
1458 bank = kzalloc(sizeof(*bank), GFP_KERNEL);
1459 if (!bank)
1460 return ERR_PTR(-ENOMEM);
1461
1462 config_group_init_type_name(&bank->group, name,
1463 &gpio_sim_bank_config_group_type);
1464 bank->num_lines = 1;
1465 bank->parent = dev;
1466 INIT_LIST_HEAD(&bank->line_list);
1467 list_add_tail(&bank->siblings, &dev->bank_list);
1468
1469 return &bank->group;
1470}
1471
1472static void gpio_sim_device_config_group_release(struct config_item *item)
1473{
1474 struct gpio_sim_device *dev = to_gpio_sim_device(item);
1475
1476 scoped_guard(mutex, &dev->lock) {
1477 if (gpio_sim_device_is_live(dev))
1478 gpio_sim_device_deactivate(dev);
1479 }
1480
1481 mutex_destroy(&dev->lock);
1482 ida_free(&gpio_sim_ida, dev->id);
1483 kfree(dev);
1484}
1485
1486static struct configfs_item_operations gpio_sim_device_config_item_ops = {
1487 .release = gpio_sim_device_config_group_release,
1488};
1489
1490static struct configfs_group_operations gpio_sim_device_config_group_ops = {
1491 .make_group = gpio_sim_device_config_make_bank_group,
1492};
1493
1494static const struct config_item_type gpio_sim_device_config_group_type = {
1495 .ct_item_ops = &gpio_sim_device_config_item_ops,
1496 .ct_group_ops = &gpio_sim_device_config_group_ops,
1497 .ct_attrs = gpio_sim_device_config_attrs,
1498 .ct_owner = THIS_MODULE,
1499};
1500
1501static struct config_group *
1502gpio_sim_config_make_device_group(struct config_group *group, const char *name)
1503{
1504 int id;
1505
1506 struct gpio_sim_device *dev __free(kfree) = kzalloc(sizeof(*dev),
1507 GFP_KERNEL);
1508 if (!dev)
1509 return ERR_PTR(-ENOMEM);
1510
1511 id = ida_alloc(&gpio_sim_ida, GFP_KERNEL);
1512 if (id < 0)
1513 return ERR_PTR(id);
1514
1515 config_group_init_type_name(&dev->group, name,
1516 &gpio_sim_device_config_group_type);
1517 dev->id = id;
1518 mutex_init(&dev->lock);
1519 INIT_LIST_HEAD(&dev->bank_list);
1520
1521 dev->bus_notifier.notifier_call = gpio_sim_bus_notifier_call;
1522 init_completion(&dev->probe_completion);
1523
1524 return &no_free_ptr(dev)->group;
1525}
1526
1527static struct configfs_group_operations gpio_sim_config_group_ops = {
1528 .make_group = gpio_sim_config_make_device_group,
1529};
1530
1531static const struct config_item_type gpio_sim_config_type = {
1532 .ct_group_ops = &gpio_sim_config_group_ops,
1533 .ct_owner = THIS_MODULE,
1534};
1535
1536static struct configfs_subsystem gpio_sim_config_subsys = {
1537 .su_group = {
1538 .cg_item = {
1539 .ci_namebuf = "gpio-sim",
1540 .ci_type = &gpio_sim_config_type,
1541 },
1542 },
1543};
1544
1545static int __init gpio_sim_init(void)
1546{
1547 int ret;
1548
1549 ret = platform_driver_register(&gpio_sim_driver);
1550 if (ret) {
1551 pr_err("Error %d while registering the platform driver\n", ret);
1552 return ret;
1553 }
1554
1555 config_group_init(&gpio_sim_config_subsys.su_group);
1556 mutex_init(&gpio_sim_config_subsys.su_mutex);
1557 ret = configfs_register_subsystem(&gpio_sim_config_subsys);
1558 if (ret) {
1559 pr_err("Error %d while registering the configfs subsystem %s\n",
1560 ret, gpio_sim_config_subsys.su_group.cg_item.ci_namebuf);
1561 mutex_destroy(&gpio_sim_config_subsys.su_mutex);
1562 platform_driver_unregister(&gpio_sim_driver);
1563 return ret;
1564 }
1565
1566 return 0;
1567}
1568module_init(gpio_sim_init);
1569
1570static void __exit gpio_sim_exit(void)
1571{
1572 configfs_unregister_subsystem(&gpio_sim_config_subsys);
1573 mutex_destroy(&gpio_sim_config_subsys.su_mutex);
1574 platform_driver_unregister(&gpio_sim_driver);
1575}
1576module_exit(gpio_sim_exit);
1577
1578MODULE_AUTHOR("Bartosz Golaszewski <brgl@bgdev.pl>");
1579MODULE_DESCRIPTION("GPIO Simulator Module");
1580MODULE_LICENSE("GPL");