1 // SPDX-License-Identifier: GPL-2.0-or-later
3 * GPIO testing driver based on configfs.
5 * Copyright (C) 2021 Bartosz Golaszewski <brgl@bgdev.pl>
8 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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>
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 */
43 static DEFINE_IDA(gpio_sim_ida);
45 struct gpio_sim_chip {
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;
54 const struct attribute_group **attr_groups;
57 struct gpio_sim_attribute {
58 struct device_attribute dev_attr;
62 static struct gpio_sim_attribute *
63 to_gpio_sim_attr(struct device_attribute *dev_attr)
65 return container_of(dev_attr, struct gpio_sim_attribute, dev_attr);
68 static int gpio_sim_apply_pull(struct gpio_sim_chip *chip,
69 unsigned int offset, int value)
71 int irq, irq_type, ret;
73 guard(mutex)(&chip->lock);
75 if (test_bit(offset, chip->request_map) &&
76 test_bit(offset, chip->direction_map)) {
77 if (value == !!test_bit(offset, chip->value_map))
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.
86 irq = irq_find_mapping(chip->irq_sim, offset);
90 irq_type = irq_get_trigger_type(irq);
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,
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);
108 __assign_bit(offset, chip->pull_map, value);
112 static int gpio_sim_get(struct gpio_chip *gc, unsigned int offset)
114 struct gpio_sim_chip *chip = gpiochip_get_data(gc);
116 guard(mutex)(&chip->lock);
118 return !!test_bit(offset, chip->value_map);
121 static void gpio_sim_set(struct gpio_chip *gc, unsigned int offset, int value)
123 struct gpio_sim_chip *chip = gpiochip_get_data(gc);
125 scoped_guard(mutex, &chip->lock)
126 __assign_bit(offset, chip->value_map, value);
129 static int gpio_sim_get_multiple(struct gpio_chip *gc,
130 unsigned long *mask, unsigned long *bits)
132 struct gpio_sim_chip *chip = gpiochip_get_data(gc);
134 scoped_guard(mutex, &chip->lock)
135 bitmap_replace(bits, bits, chip->value_map, mask, gc->ngpio);
140 static void gpio_sim_set_multiple(struct gpio_chip *gc,
141 unsigned long *mask, unsigned long *bits)
143 struct gpio_sim_chip *chip = gpiochip_get_data(gc);
145 scoped_guard(mutex, &chip->lock)
146 bitmap_replace(chip->value_map, chip->value_map, bits, mask,
150 static int gpio_sim_direction_output(struct gpio_chip *gc,
151 unsigned int offset, int value)
153 struct gpio_sim_chip *chip = gpiochip_get_data(gc);
155 scoped_guard(mutex, &chip->lock) {
156 __clear_bit(offset, chip->direction_map);
157 __assign_bit(offset, chip->value_map, value);
163 static int gpio_sim_direction_input(struct gpio_chip *gc, unsigned int offset)
165 struct gpio_sim_chip *chip = gpiochip_get_data(gc);
167 scoped_guard(mutex, &chip->lock)
168 __set_bit(offset, chip->direction_map);
173 static int gpio_sim_get_direction(struct gpio_chip *gc, unsigned int offset)
175 struct gpio_sim_chip *chip = gpiochip_get_data(gc);
178 scoped_guard(mutex, &chip->lock)
179 direction = !!test_bit(offset, chip->direction_map);
181 return direction ? GPIO_LINE_DIRECTION_IN : GPIO_LINE_DIRECTION_OUT;
184 static int gpio_sim_set_config(struct gpio_chip *gc, unsigned int offset,
185 unsigned long config)
187 struct gpio_sim_chip *chip = gpiochip_get_data(gc);
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);
201 static int gpio_sim_to_irq(struct gpio_chip *gc, unsigned int offset)
203 struct gpio_sim_chip *chip = gpiochip_get_data(gc);
205 return irq_create_mapping(chip->irq_sim, offset);
208 static int gpio_sim_request(struct gpio_chip *gc, unsigned int offset)
210 struct gpio_sim_chip *chip = gpiochip_get_data(gc);
212 scoped_guard(mutex, &chip->lock)
213 __set_bit(offset, chip->request_map);
218 static void gpio_sim_free(struct gpio_chip *gc, unsigned int offset)
220 struct gpio_sim_chip *chip = gpiochip_get_data(gc);
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);
229 static void gpio_sim_dbg_show(struct seq_file *seq, struct gpio_chip *gc)
231 struct gpio_sim_chip *chip = gpiochip_get_data(gc);
235 guard(mutex)(&chip->lock);
237 for_each_requested_gpio(gc, i, label)
238 seq_printf(seq, " gpio-%-3d (%s) %s,%s\n",
241 test_bit(i, chip->direction_map) ? "input" :
242 test_bit(i, chip->value_map) ? "output-high" :
244 test_bit(i, chip->pull_map) ? "pull-up" :
248 static ssize_t gpio_sim_sysfs_val_show(struct device *dev,
249 struct device_attribute *attr, char *buf)
251 struct gpio_sim_attribute *line_attr = to_gpio_sim_attr(attr);
252 struct gpio_sim_chip *chip = dev_get_drvdata(dev);
255 scoped_guard(mutex, &chip->lock)
256 val = !!test_bit(line_attr->offset, chip->value_map);
258 return sysfs_emit(buf, "%d\n", val);
261 static ssize_t gpio_sim_sysfs_val_store(struct device *dev,
262 struct device_attribute *attr,
263 const char *buf, size_t count)
266 * Not assigning this function will result in write() returning -EIO
267 * which is confusing. Return -EPERM explicitly.
272 static const char *const gpio_sim_sysfs_pull_strings[] = {
277 static ssize_t gpio_sim_sysfs_pull_show(struct device *dev,
278 struct device_attribute *attr,
281 struct gpio_sim_attribute *line_attr = to_gpio_sim_attr(attr);
282 struct gpio_sim_chip *chip = dev_get_drvdata(dev);
285 scoped_guard(mutex, &chip->lock)
286 pull = !!test_bit(line_attr->offset, chip->pull_map);
288 return sysfs_emit(buf, "%s\n", gpio_sim_sysfs_pull_strings[pull]);
291 static ssize_t gpio_sim_sysfs_pull_store(struct device *dev,
292 struct device_attribute *attr,
293 const char *buf, size_t len)
295 struct gpio_sim_attribute *line_attr = to_gpio_sim_attr(attr);
296 struct gpio_sim_chip *chip = dev_get_drvdata(dev);
299 pull = sysfs_match_string(gpio_sim_sysfs_pull_strings, buf);
303 ret = gpio_sim_apply_pull(chip, line_attr->offset, pull);
310 static void gpio_sim_mutex_destroy(void *data)
312 struct mutex *lock = data;
317 static void gpio_sim_put_device(void *data)
319 struct device *dev = data;
324 static void gpio_sim_dispose_mappings(void *data)
326 struct gpio_sim_chip *chip = data;
329 for (i = 0; i < chip->gc.ngpio; i++)
330 irq_dispose_mapping(irq_find_mapping(chip->irq_sim, i));
333 static void gpio_sim_sysfs_remove(void *data)
335 struct gpio_sim_chip *chip = data;
337 sysfs_remove_groups(&chip->dev->kobj, chip->attr_groups);
340 static int gpio_sim_setup_sysfs(struct gpio_sim_chip *chip)
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;
350 chip->attr_groups = devm_kcalloc(dev, sizeof(*chip->attr_groups),
351 num_lines + 1, GFP_KERNEL);
352 if (!chip->attr_groups)
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),
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)
364 attr_group->name = devm_kasprintf(dev, GFP_KERNEL,
366 if (!attr_group->name)
369 val_attr->offset = pull_attr->offset = i;
371 val_dev_attr = &val_attr->dev_attr;
372 pull_dev_attr = &pull_attr->dev_attr;
374 sysfs_attr_init(&val_dev_attr->attr);
375 sysfs_attr_init(&pull_dev_attr->attr);
377 val_dev_attr->attr.name = "value";
378 pull_dev_attr->attr.name = "pull";
380 val_dev_attr->attr.mode = pull_dev_attr->attr.mode = 0644;
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;
387 attrs[0] = &val_dev_attr->attr;
388 attrs[1] = &pull_dev_attr->attr;
390 attr_group->attrs = attrs;
391 chip->attr_groups[i] = attr_group;
394 ret = sysfs_create_groups(&chip->dev->kobj, chip->attr_groups);
398 return devm_add_action_or_reset(dev, gpio_sim_sysfs_remove, chip);
401 static int gpio_sim_dev_match_fwnode(struct device *dev, void *data)
403 return device_match_fwnode(dev, data);
406 static int gpio_sim_add_bank(struct fwnode_handle *swnode, struct device *dev)
408 struct gpio_sim_chip *chip;
409 struct gpio_chip *gc;
414 ret = fwnode_property_read_u32(swnode, "ngpios", &num_lines);
418 if (num_lines > GPIO_SIM_NGPIO_MAX)
421 ret = fwnode_property_read_string(swnode, "gpio-sim,label", &label);
423 label = devm_kasprintf(dev, GFP_KERNEL, "%s-%pfwP",
424 dev_name(dev), swnode);
429 chip = devm_kzalloc(dev, sizeof(*chip), GFP_KERNEL);
433 chip->request_map = devm_bitmap_zalloc(dev, num_lines, GFP_KERNEL);
434 if (!chip->request_map)
437 chip->direction_map = devm_bitmap_alloc(dev, num_lines, GFP_KERNEL);
438 if (!chip->direction_map)
441 /* Default to input mode. */
442 bitmap_fill(chip->direction_map, num_lines);
444 chip->value_map = devm_bitmap_zalloc(dev, num_lines, GFP_KERNEL);
445 if (!chip->value_map)
448 chip->pull_map = devm_bitmap_zalloc(dev, num_lines, GFP_KERNEL);
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);
456 ret = devm_add_action_or_reset(dev, gpio_sim_dispose_mappings, chip);
460 mutex_init(&chip->lock);
461 ret = devm_add_action_or_reset(dev, gpio_sim_mutex_destroy,
468 gc->ngpio = num_lines;
470 gc->owner = THIS_MODULE;
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;
487 ret = devm_gpiochip_add_data(dev, gc, chip);
491 chip->dev = device_find_child(dev, swnode, gpio_sim_dev_match_fwnode);
495 ret = devm_add_action_or_reset(dev, gpio_sim_put_device, chip->dev);
499 /* Used by sysfs callbacks. */
500 dev_set_drvdata(chip->dev, chip);
502 return gpio_sim_setup_sysfs(chip);
505 static int gpio_sim_probe(struct platform_device *pdev)
507 struct device *dev = &pdev->dev;
508 struct fwnode_handle *swnode;
511 device_for_each_child_node(dev, swnode) {
512 ret = gpio_sim_add_bank(swnode, dev);
514 fwnode_handle_put(swnode);
522 static const struct of_device_id gpio_sim_of_match[] = {
523 { .compatible = "gpio-simulator" },
526 MODULE_DEVICE_TABLE(of, gpio_sim_of_match);
528 static struct platform_driver gpio_sim_driver = {
531 .of_match_table = gpio_sim_of_match,
533 .probe = gpio_sim_probe,
536 struct gpio_sim_device {
537 struct config_group group;
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
544 struct platform_device *pdev;
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.
553 * We use this lock for protecting all data structures owned by this
559 * This is used to synchronously wait for the driver's probe to complete
560 * and notify the user-space about any errors.
562 struct notifier_block bus_notifier;
563 struct completion probe_completion;
566 struct gpiod_hog *hogs;
568 struct list_head bank_list;
571 /* This is called with dev->lock already taken. */
572 static int gpio_sim_bus_notifier_call(struct notifier_block *nb,
573 unsigned long action, void *data)
575 struct gpio_sim_device *simdev = container_of(nb,
576 struct gpio_sim_device,
578 struct device *dev = data;
581 snprintf(devname, sizeof(devname), "gpio-sim.%u", simdev->id);
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;
591 complete(&simdev->probe_completion);
598 static struct gpio_sim_device *to_gpio_sim_device(struct config_item *item)
600 struct config_group *group = to_config_group(item);
602 return container_of(group, struct gpio_sim_device, group);
605 struct gpio_sim_bank {
606 struct config_group group;
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...
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
619 * Same for other structures.
621 struct gpio_sim_device *parent;
622 struct list_head siblings;
625 unsigned int num_lines;
627 struct list_head line_list;
629 struct fwnode_handle *swnode;
632 static struct gpio_sim_bank *to_gpio_sim_bank(struct config_item *item)
634 struct config_group *group = to_config_group(item);
636 return container_of(group, struct gpio_sim_bank, group);
639 static bool gpio_sim_bank_has_label(struct gpio_sim_bank *bank)
641 return bank->label && *bank->label;
644 static struct gpio_sim_device *
645 gpio_sim_bank_get_device(struct gpio_sim_bank *bank)
652 struct gpio_sim_line {
653 struct config_group group;
655 struct gpio_sim_bank *parent;
656 struct list_head siblings;
661 /* There can only be one hog per line. */
662 struct gpio_sim_hog *hog;
665 static struct gpio_sim_line *to_gpio_sim_line(struct config_item *item)
667 struct config_group *group = to_config_group(item);
669 return container_of(group, struct gpio_sim_line, group);
672 static struct gpio_sim_device *
673 gpio_sim_line_get_device(struct gpio_sim_line *line)
675 struct gpio_sim_bank *bank = line->parent;
677 return gpio_sim_bank_get_device(bank);
680 struct gpio_sim_hog {
681 struct config_item item;
682 struct gpio_sim_line *parent;
688 static struct gpio_sim_hog *to_gpio_sim_hog(struct config_item *item)
690 return container_of(item, struct gpio_sim_hog, item);
693 static struct gpio_sim_device *gpio_sim_hog_get_device(struct gpio_sim_hog *hog)
695 struct gpio_sim_line *line = hog->parent;
697 return gpio_sim_line_get_device(line);
700 static bool gpio_sim_device_is_live_unlocked(struct gpio_sim_device *dev)
705 static char *gpio_sim_strdup_trimmed(const char *str, size_t count)
709 trimmed = kstrndup(skip_spaces(str), count, GFP_KERNEL);
713 return strim(trimmed);
716 static ssize_t gpio_sim_device_config_dev_name_show(struct config_item *item,
719 struct gpio_sim_device *dev = to_gpio_sim_device(item);
720 struct platform_device *pdev;
722 guard(mutex)(&dev->lock);
726 return sprintf(page, "%s\n", dev_name(&pdev->dev));
728 return sprintf(page, "gpio-sim.%d\n", dev->id);
731 CONFIGFS_ATTR_RO(gpio_sim_device_config_, dev_name);
734 gpio_sim_device_config_live_show(struct config_item *item, char *page)
736 struct gpio_sim_device *dev = to_gpio_sim_device(item);
739 scoped_guard(mutex, &dev->lock)
740 live = gpio_sim_device_is_live_unlocked(dev);
742 return sprintf(page, "%c\n", live ? '1' : '0');
745 static unsigned int gpio_sim_get_line_names_size(struct gpio_sim_bank *bank)
747 struct gpio_sim_line *line;
748 unsigned int size = 0;
750 list_for_each_entry(line, &bank->line_list, siblings) {
751 if (!line->name || (line->offset >= bank->num_lines))
754 size = max(size, line->offset + 1);
761 gpio_sim_set_line_names(struct gpio_sim_bank *bank, char **line_names)
763 struct gpio_sim_line *line;
765 list_for_each_entry(line, &bank->line_list, siblings) {
766 if (!line->name || (line->offset >= bank->num_lines))
769 line_names[line->offset] = line->name;
773 static void gpio_sim_remove_hogs(struct gpio_sim_device *dev)
775 struct gpiod_hog *hog;
780 gpiod_remove_hogs(dev->hogs);
782 for (hog = dev->hogs; hog->chip_label; hog++) {
783 kfree(hog->chip_label);
784 kfree(hog->line_name);
791 static int gpio_sim_add_hogs(struct gpio_sim_device *dev)
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;
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)
811 /* Allocate one more for the sentinel. */
812 dev->hogs = kcalloc(num_hogs + 1, sizeof(*dev->hogs), GFP_KERNEL);
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)
824 hog = &dev->hogs[idx++];
827 * We need to make this string manually because at this
828 * point the device doesn't exist yet and so dev_name()
831 if (gpio_sim_bank_has_label(bank))
832 hog->chip_label = kstrdup(bank->label,
835 hog->chip_label = kasprintf(GFP_KERNEL,
839 if (!hog->chip_label) {
840 gpio_sim_remove_hogs(dev);
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
850 if (line->hog->name) {
851 hog->line_name = kstrdup(line->hog->name,
853 if (!hog->line_name) {
854 gpio_sim_remove_hogs(dev);
859 hog->chip_hwnum = line->offset;
860 hog->dflags = line->hog->dir;
864 gpiod_add_hogs(dev->hogs);
869 static struct fwnode_handle *
870 gpio_sim_make_bank_swnode(struct gpio_sim_bank *bank,
871 struct fwnode_handle *parent)
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;
877 memset(properties, 0, sizeof(properties));
879 properties[prop_idx++] = PROPERTY_ENTRY_U32("ngpios", bank->num_lines);
881 if (gpio_sim_bank_has_label(bank))
882 properties[prop_idx++] = PROPERTY_ENTRY_STRING("gpio-sim,label",
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),
890 return ERR_PTR(-ENOMEM);
892 gpio_sim_set_line_names(bank, line_names);
894 properties[prop_idx++] = PROPERTY_ENTRY_STRING_ARRAY_LEN(
896 line_names, line_names_size);
899 return fwnode_create_software_node(properties, parent);
902 static void gpio_sim_remove_swnode_recursive(struct fwnode_handle *swnode)
904 struct fwnode_handle *child;
906 fwnode_for_each_child_node(swnode, child)
907 fwnode_remove_software_node(child);
909 fwnode_remove_software_node(swnode);
912 static bool gpio_sim_bank_labels_non_unique(struct gpio_sim_device *dev)
914 struct gpio_sim_bank *this, *pos;
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))
921 if (strcmp(this->label, pos->label) == 0)
929 static int gpio_sim_device_activate_unlocked(struct gpio_sim_device *dev)
931 struct platform_device_info pdevinfo;
932 struct fwnode_handle *swnode;
933 struct platform_device *pdev;
934 struct gpio_sim_bank *bank;
937 if (list_empty(&dev->bank_list))
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
945 if (gpio_sim_bank_labels_non_unique(dev))
948 memset(&pdevinfo, 0, sizeof(pdevinfo));
950 swnode = fwnode_create_software_node(NULL, NULL);
952 return PTR_ERR(swnode);
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);
963 ret = gpio_sim_add_hogs(dev);
965 gpio_sim_remove_swnode_recursive(swnode);
969 pdevinfo.name = "gpio-sim";
970 pdevinfo.fwnode = swnode;
971 pdevinfo.id = dev->id;
973 reinit_completion(&dev->probe_completion);
974 dev->driver_bound = false;
975 bus_register_notifier(&platform_bus_type, &dev->bus_notifier);
977 pdev = platform_device_register_full(&pdevinfo);
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);
985 wait_for_completion(&dev->probe_completion);
986 bus_unregister_notifier(&platform_bus_type, &dev->bus_notifier);
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);
1001 static void gpio_sim_device_deactivate_unlocked(struct gpio_sim_device *dev)
1003 struct fwnode_handle *swnode;
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);
1013 gpio_sim_device_config_live_store(struct config_item *item,
1014 const char *page, size_t count)
1016 struct gpio_sim_device *dev = to_gpio_sim_device(item);
1020 ret = kstrtobool(page, &live);
1024 guard(mutex)(&dev->lock);
1026 if (live == gpio_sim_device_is_live_unlocked(dev))
1029 ret = gpio_sim_device_activate_unlocked(dev);
1031 gpio_sim_device_deactivate_unlocked(dev);
1033 return ret ?: count;
1036 CONFIGFS_ATTR(gpio_sim_device_config_, live);
1038 static struct configfs_attribute *gpio_sim_device_config_attrs[] = {
1039 &gpio_sim_device_config_attr_dev_name,
1040 &gpio_sim_device_config_attr_live,
1044 struct gpio_sim_chip_name_ctx {
1045 struct fwnode_handle *swnode;
1049 static int gpio_sim_emit_chip_name(struct device *dev, void *data)
1051 struct gpio_sim_chip_name_ctx *ctx = data;
1053 /* This would be the sysfs device exported in /sys/class/gpio. */
1057 if (device_match_fwnode(dev, ctx->swnode))
1058 return sprintf(ctx->page, "%s\n", dev_name(dev));
1063 static ssize_t gpio_sim_bank_config_chip_name_show(struct config_item *item,
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 };
1070 guard(mutex)(&dev->lock);
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);
1076 return sprintf(page, "none\n");
1079 CONFIGFS_ATTR_RO(gpio_sim_bank_config_, chip_name);
1082 gpio_sim_bank_config_label_show(struct config_item *item, char *page)
1084 struct gpio_sim_bank *bank = to_gpio_sim_bank(item);
1085 struct gpio_sim_device *dev = gpio_sim_bank_get_device(bank);
1087 guard(mutex)(&dev->lock);
1089 return sprintf(page, "%s\n", bank->label ?: "");
1092 static ssize_t gpio_sim_bank_config_label_store(struct config_item *item,
1093 const char *page, size_t count)
1095 struct gpio_sim_bank *bank = to_gpio_sim_bank(item);
1096 struct gpio_sim_device *dev = gpio_sim_bank_get_device(bank);
1099 guard(mutex)(&dev->lock);
1101 if (gpio_sim_device_is_live_unlocked(dev))
1104 trimmed = gpio_sim_strdup_trimmed(page, count);
1109 bank->label = trimmed;
1114 CONFIGFS_ATTR(gpio_sim_bank_config_, label);
1117 gpio_sim_bank_config_num_lines_show(struct config_item *item, char *page)
1119 struct gpio_sim_bank *bank = to_gpio_sim_bank(item);
1120 struct gpio_sim_device *dev = gpio_sim_bank_get_device(bank);
1122 guard(mutex)(&dev->lock);
1124 return sprintf(page, "%u\n", bank->num_lines);
1128 gpio_sim_bank_config_num_lines_store(struct config_item *item,
1129 const char *page, size_t count)
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;
1136 ret = kstrtouint(page, 0, &num_lines);
1143 guard(mutex)(&dev->lock);
1145 if (gpio_sim_device_is_live_unlocked(dev))
1148 bank->num_lines = num_lines;
1153 CONFIGFS_ATTR(gpio_sim_bank_config_, num_lines);
1155 static 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,
1163 gpio_sim_line_config_name_show(struct config_item *item, char *page)
1165 struct gpio_sim_line *line = to_gpio_sim_line(item);
1166 struct gpio_sim_device *dev = gpio_sim_line_get_device(line);
1168 guard(mutex)(&dev->lock);
1170 return sprintf(page, "%s\n", line->name ?: "");
1173 static ssize_t gpio_sim_line_config_name_store(struct config_item *item,
1174 const char *page, size_t count)
1176 struct gpio_sim_line *line = to_gpio_sim_line(item);
1177 struct gpio_sim_device *dev = gpio_sim_line_get_device(line);
1180 guard(mutex)(&dev->lock);
1182 if (gpio_sim_device_is_live_unlocked(dev))
1185 trimmed = gpio_sim_strdup_trimmed(page, count);
1190 line->name = trimmed;
1195 CONFIGFS_ATTR(gpio_sim_line_config_, name);
1197 static struct configfs_attribute *gpio_sim_line_config_attrs[] = {
1198 &gpio_sim_line_config_attr_name,
1202 static ssize_t gpio_sim_hog_config_name_show(struct config_item *item,
1205 struct gpio_sim_hog *hog = to_gpio_sim_hog(item);
1206 struct gpio_sim_device *dev = gpio_sim_hog_get_device(hog);
1208 guard(mutex)(&dev->lock);
1210 return sprintf(page, "%s\n", hog->name ?: "");
1213 static ssize_t gpio_sim_hog_config_name_store(struct config_item *item,
1214 const char *page, size_t count)
1216 struct gpio_sim_hog *hog = to_gpio_sim_hog(item);
1217 struct gpio_sim_device *dev = gpio_sim_hog_get_device(hog);
1220 guard(mutex)(&dev->lock);
1222 if (gpio_sim_device_is_live_unlocked(dev))
1225 trimmed = gpio_sim_strdup_trimmed(page, count);
1230 hog->name = trimmed;
1235 CONFIGFS_ATTR(gpio_sim_hog_config_, name);
1237 static ssize_t gpio_sim_hog_config_direction_show(struct config_item *item,
1240 struct gpio_sim_hog *hog = to_gpio_sim_hog(item);
1241 struct gpio_sim_device *dev = gpio_sim_hog_get_device(hog);
1245 scoped_guard(mutex, &dev->lock)
1252 case GPIOD_OUT_HIGH:
1253 repr = "output-high";
1256 repr = "output-low";
1259 /* This would be a programmer bug. */
1260 WARN(1, "Unexpected hog direction value: %d", dir);
1264 return sprintf(page, "%s\n", repr);
1268 gpio_sim_hog_config_direction_store(struct config_item *item,
1269 const char *page, size_t count)
1271 struct gpio_sim_hog *hog = to_gpio_sim_hog(item);
1272 struct gpio_sim_device *dev = gpio_sim_hog_get_device(hog);
1275 guard(mutex)(&dev->lock);
1277 if (gpio_sim_device_is_live_unlocked(dev))
1280 if (sysfs_streq(page, "input"))
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;
1294 CONFIGFS_ATTR(gpio_sim_hog_config_, direction);
1296 static struct configfs_attribute *gpio_sim_hog_config_attrs[] = {
1297 &gpio_sim_hog_config_attr_name,
1298 &gpio_sim_hog_config_attr_direction,
1302 static void gpio_sim_hog_config_item_release(struct config_item *item)
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);
1308 scoped_guard(mutex, &dev->lock)
1315 static struct configfs_item_operations gpio_sim_hog_config_item_ops = {
1316 .release = gpio_sim_hog_config_item_release,
1319 static 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,
1325 static struct config_item *
1326 gpio_sim_line_config_make_hog_item(struct config_group *group, const char *name)
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;
1332 if (strcmp(name, "hog") != 0)
1333 return ERR_PTR(-EINVAL);
1335 guard(mutex)(&dev->lock);
1337 hog = kzalloc(sizeof(*hog), GFP_KERNEL);
1339 return ERR_PTR(-ENOMEM);
1341 config_item_init_type_name(&hog->item, name,
1342 &gpio_sim_hog_config_type);
1344 hog->dir = GPIOD_IN;
1352 static void gpio_sim_line_config_group_release(struct config_item *item)
1354 struct gpio_sim_line *line = to_gpio_sim_line(item);
1355 struct gpio_sim_device *dev = gpio_sim_line_get_device(line);
1357 scoped_guard(mutex, &dev->lock)
1358 list_del(&line->siblings);
1364 static struct configfs_item_operations gpio_sim_line_config_item_ops = {
1365 .release = gpio_sim_line_config_group_release,
1368 static struct configfs_group_operations gpio_sim_line_config_group_ops = {
1369 .make_item = gpio_sim_line_config_make_hog_item,
1372 static 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,
1379 static struct config_group *
1380 gpio_sim_bank_config_make_line_group(struct config_group *group,
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;
1389 ret = sscanf(name, "line%u%n", &offset, &nchar);
1390 if (ret != 1 || nchar != strlen(name))
1391 return ERR_PTR(-EINVAL);
1393 guard(mutex)(&dev->lock);
1395 if (gpio_sim_device_is_live_unlocked(dev))
1396 return ERR_PTR(-EBUSY);
1398 line = kzalloc(sizeof(*line), GFP_KERNEL);
1400 return ERR_PTR(-ENOMEM);
1402 config_group_init_type_name(&line->group, name,
1403 &gpio_sim_line_config_type);
1405 line->parent = bank;
1406 line->offset = offset;
1407 list_add_tail(&line->siblings, &bank->line_list);
1409 return &line->group;
1412 static void gpio_sim_bank_config_group_release(struct config_item *item)
1414 struct gpio_sim_bank *bank = to_gpio_sim_bank(item);
1415 struct gpio_sim_device *dev = gpio_sim_bank_get_device(bank);
1417 scoped_guard(mutex, &dev->lock)
1418 list_del(&bank->siblings);
1424 static struct configfs_item_operations gpio_sim_bank_config_item_ops = {
1425 .release = gpio_sim_bank_config_group_release,
1428 static struct configfs_group_operations gpio_sim_bank_config_group_ops = {
1429 .make_group = gpio_sim_bank_config_make_line_group,
1432 static 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,
1439 static struct config_group *
1440 gpio_sim_device_config_make_bank_group(struct config_group *group,
1443 struct gpio_sim_device *dev = to_gpio_sim_device(&group->cg_item);
1444 struct gpio_sim_bank *bank;
1446 guard(mutex)(&dev->lock);
1448 if (gpio_sim_device_is_live_unlocked(dev))
1449 return ERR_PTR(-EBUSY);
1451 bank = kzalloc(sizeof(*bank), GFP_KERNEL);
1453 return ERR_PTR(-ENOMEM);
1455 config_group_init_type_name(&bank->group, name,
1456 &gpio_sim_bank_config_group_type);
1457 bank->num_lines = 1;
1459 INIT_LIST_HEAD(&bank->line_list);
1460 list_add_tail(&bank->siblings, &dev->bank_list);
1462 return &bank->group;
1465 static void gpio_sim_device_config_group_release(struct config_item *item)
1467 struct gpio_sim_device *dev = to_gpio_sim_device(item);
1469 scoped_guard(mutex, &dev->lock) {
1470 if (gpio_sim_device_is_live_unlocked(dev))
1471 gpio_sim_device_deactivate_unlocked(dev);
1474 mutex_destroy(&dev->lock);
1475 ida_free(&gpio_sim_ida, dev->id);
1479 static struct configfs_item_operations gpio_sim_device_config_item_ops = {
1480 .release = gpio_sim_device_config_group_release,
1483 static struct configfs_group_operations gpio_sim_device_config_group_ops = {
1484 .make_group = gpio_sim_device_config_make_bank_group,
1487 static 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,
1494 static struct config_group *
1495 gpio_sim_config_make_device_group(struct config_group *group, const char *name)
1499 struct gpio_sim_device *dev __free(kfree) = kzalloc(sizeof(*dev),
1502 return ERR_PTR(-ENOMEM);
1504 id = ida_alloc(&gpio_sim_ida, GFP_KERNEL);
1508 config_group_init_type_name(&dev->group, name,
1509 &gpio_sim_device_config_group_type);
1511 mutex_init(&dev->lock);
1512 INIT_LIST_HEAD(&dev->bank_list);
1514 dev->bus_notifier.notifier_call = gpio_sim_bus_notifier_call;
1515 init_completion(&dev->probe_completion);
1517 return &no_free_ptr(dev)->group;
1520 static struct configfs_group_operations gpio_sim_config_group_ops = {
1521 .make_group = gpio_sim_config_make_device_group,
1524 static const struct config_item_type gpio_sim_config_type = {
1525 .ct_group_ops = &gpio_sim_config_group_ops,
1526 .ct_owner = THIS_MODULE,
1529 static struct configfs_subsystem gpio_sim_config_subsys = {
1532 .ci_namebuf = "gpio-sim",
1533 .ci_type = &gpio_sim_config_type,
1538 static int __init gpio_sim_init(void)
1542 ret = platform_driver_register(&gpio_sim_driver);
1544 pr_err("Error %d while registering the platform driver\n", ret);
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);
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);
1561 module_init(gpio_sim_init);
1563 static void __exit gpio_sim_exit(void)
1565 configfs_unregister_subsystem(&gpio_sim_config_subsys);
1566 mutex_destroy(&gpio_sim_config_subsys.su_mutex);
1567 platform_driver_unregister(&gpio_sim_driver);
1569 module_exit(gpio_sim_exit);
1571 MODULE_AUTHOR("Bartosz Golaszewski <brgl@bgdev.pl>");
1572 MODULE_DESCRIPTION("GPIO Simulator Module");
1573 MODULE_LICENSE("GPL");