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