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/completion.h>
12 #include <linux/configfs.h>
13 #include <linux/device.h>
14 #include <linux/gpio/driver.h>
15 #include <linux/gpio/machine.h>
16 #include <linux/idr.h>
17 #include <linux/interrupt.h>
18 #include <linux/irq.h>
19 #include <linux/irq_sim.h>
20 #include <linux/list.h>
21 #include <linux/mod_devicetable.h>
22 #include <linux/module.h>
23 #include <linux/mutex.h>
24 #include <linux/notifier.h>
25 #include <linux/platform_device.h>
26 #include <linux/property.h>
27 #include <linux/slab.h>
28 #include <linux/string.h>
29 #include <linux/string_helpers.h>
30 #include <linux/sysfs.h>
34 #define GPIO_SIM_PROP_MAX 4 /* Max 3 properties + sentinel. */
35 #define GPIO_SIM_NUM_ATTRS 3 /* value, pull and sentinel */
37 static DEFINE_IDA(gpio_sim_ida);
39 struct gpio_sim_chip {
41 unsigned long *direction_map;
42 unsigned long *value_map;
43 unsigned long *pull_map;
44 struct irq_domain *irq_sim;
46 const struct attribute_group **attr_groups;
49 struct gpio_sim_attribute {
50 struct device_attribute dev_attr;
54 static struct gpio_sim_attribute *
55 to_gpio_sim_attr(struct device_attribute *dev_attr)
57 return container_of(dev_attr, struct gpio_sim_attribute, dev_attr);
60 static int gpio_sim_apply_pull(struct gpio_sim_chip *chip,
61 unsigned int offset, int value)
63 int irq, irq_type, ret;
64 struct gpio_desc *desc;
68 desc = &gc->gpiodev->descs[offset];
70 mutex_lock(&chip->lock);
72 if (test_bit(FLAG_REQUESTED, &desc->flags) &&
73 !test_bit(FLAG_IS_OUT, &desc->flags)) {
74 if (value == !!test_bit(offset, chip->value_map))
78 * This is fine - it just means, nobody is listening
79 * for interrupts on this line, otherwise
80 * irq_create_mapping() would have been called from
81 * the to_irq() callback.
83 irq = irq_find_mapping(chip->irq_sim, offset);
87 irq_type = irq_get_trigger_type(irq);
89 if ((value && (irq_type & IRQ_TYPE_EDGE_RISING)) ||
90 (!value && (irq_type & IRQ_TYPE_EDGE_FALLING))) {
91 ret = irq_set_irqchip_state(irq, IRQCHIP_STATE_PENDING,
99 /* Change the value unless we're actively driving the line. */
100 if (!test_bit(FLAG_REQUESTED, &desc->flags) ||
101 !test_bit(FLAG_IS_OUT, &desc->flags))
102 __assign_bit(offset, chip->value_map, value);
105 __assign_bit(offset, chip->pull_map, value);
106 mutex_unlock(&chip->lock);
110 static int gpio_sim_get(struct gpio_chip *gc, unsigned int offset)
112 struct gpio_sim_chip *chip = gpiochip_get_data(gc);
115 mutex_lock(&chip->lock);
116 ret = !!test_bit(offset, chip->value_map);
117 mutex_unlock(&chip->lock);
122 static void gpio_sim_set(struct gpio_chip *gc, unsigned int offset, int value)
124 struct gpio_sim_chip *chip = gpiochip_get_data(gc);
126 mutex_lock(&chip->lock);
127 __assign_bit(offset, chip->value_map, value);
128 mutex_unlock(&chip->lock);
131 static int gpio_sim_get_multiple(struct gpio_chip *gc,
132 unsigned long *mask, unsigned long *bits)
134 struct gpio_sim_chip *chip = gpiochip_get_data(gc);
136 mutex_lock(&chip->lock);
137 bitmap_copy(bits, chip->value_map, gc->ngpio);
138 mutex_unlock(&chip->lock);
143 static void gpio_sim_set_multiple(struct gpio_chip *gc,
144 unsigned long *mask, unsigned long *bits)
146 struct gpio_sim_chip *chip = gpiochip_get_data(gc);
148 mutex_lock(&chip->lock);
149 bitmap_copy(chip->value_map, bits, gc->ngpio);
150 mutex_unlock(&chip->lock);
153 static int gpio_sim_direction_output(struct gpio_chip *gc,
154 unsigned int offset, int value)
156 struct gpio_sim_chip *chip = gpiochip_get_data(gc);
158 mutex_lock(&chip->lock);
159 __clear_bit(offset, chip->direction_map);
160 __assign_bit(offset, chip->value_map, value);
161 mutex_unlock(&chip->lock);
166 static int gpio_sim_direction_input(struct gpio_chip *gc, unsigned int offset)
168 struct gpio_sim_chip *chip = gpiochip_get_data(gc);
170 mutex_lock(&chip->lock);
171 __set_bit(offset, chip->direction_map);
172 mutex_unlock(&chip->lock);
177 static int gpio_sim_get_direction(struct gpio_chip *gc, unsigned int offset)
179 struct gpio_sim_chip *chip = gpiochip_get_data(gc);
182 mutex_lock(&chip->lock);
183 direction = !!test_bit(offset, chip->direction_map);
184 mutex_unlock(&chip->lock);
186 return direction ? GPIO_LINE_DIRECTION_IN : GPIO_LINE_DIRECTION_OUT;
189 static int gpio_sim_set_config(struct gpio_chip *gc,
190 unsigned int offset, unsigned long config)
192 struct gpio_sim_chip *chip = gpiochip_get_data(gc);
194 switch (pinconf_to_config_param(config)) {
195 case PIN_CONFIG_BIAS_PULL_UP:
196 return gpio_sim_apply_pull(chip, offset, 1);
197 case PIN_CONFIG_BIAS_PULL_DOWN:
198 return gpio_sim_apply_pull(chip, offset, 0);
206 static int gpio_sim_to_irq(struct gpio_chip *gc, unsigned int offset)
208 struct gpio_sim_chip *chip = gpiochip_get_data(gc);
210 return irq_create_mapping(chip->irq_sim, offset);
213 static void gpio_sim_free(struct gpio_chip *gc, unsigned int offset)
215 struct gpio_sim_chip *chip = gpiochip_get_data(gc);
217 mutex_lock(&chip->lock);
218 __assign_bit(offset, chip->value_map, !!test_bit(offset, chip->pull_map));
219 mutex_unlock(&chip->lock);
222 static ssize_t gpio_sim_sysfs_val_show(struct device *dev,
223 struct device_attribute *attr, char *buf)
225 struct gpio_sim_attribute *line_attr = to_gpio_sim_attr(attr);
226 struct gpio_sim_chip *chip = dev_get_drvdata(dev);
229 mutex_lock(&chip->lock);
230 val = !!test_bit(line_attr->offset, chip->value_map);
231 mutex_unlock(&chip->lock);
233 return sysfs_emit(buf, "%d\n", val);
236 static ssize_t gpio_sim_sysfs_val_store(struct device *dev,
237 struct device_attribute *attr,
238 const char *buf, size_t count)
241 * Not assigning this function will result in write() returning -EIO
242 * which is confusing. Return -EPERM explicitly.
247 static const char *const gpio_sim_sysfs_pull_strings[] = {
252 static ssize_t gpio_sim_sysfs_pull_show(struct device *dev,
253 struct device_attribute *attr,
256 struct gpio_sim_attribute *line_attr = to_gpio_sim_attr(attr);
257 struct gpio_sim_chip *chip = dev_get_drvdata(dev);
260 mutex_lock(&chip->lock);
261 pull = !!test_bit(line_attr->offset, chip->pull_map);
262 mutex_unlock(&chip->lock);
264 return sysfs_emit(buf, "%s\n", gpio_sim_sysfs_pull_strings[pull]);
267 static ssize_t gpio_sim_sysfs_pull_store(struct device *dev,
268 struct device_attribute *attr,
269 const char *buf, size_t len)
271 struct gpio_sim_attribute *line_attr = to_gpio_sim_attr(attr);
272 struct gpio_sim_chip *chip = dev_get_drvdata(dev);
275 pull = sysfs_match_string(gpio_sim_sysfs_pull_strings, buf);
279 ret = gpio_sim_apply_pull(chip, line_attr->offset, pull);
286 static void gpio_sim_mutex_destroy(void *data)
288 struct mutex *lock = data;
293 static void gpio_sim_sysfs_remove(void *data)
295 struct gpio_sim_chip *chip = data;
297 sysfs_remove_groups(&chip->gc.gpiodev->dev.kobj, chip->attr_groups);
300 static int gpio_sim_setup_sysfs(struct gpio_sim_chip *chip)
302 struct device_attribute *val_dev_attr, *pull_dev_attr;
303 struct gpio_sim_attribute *val_attr, *pull_attr;
304 unsigned int num_lines = chip->gc.ngpio;
305 struct device *dev = chip->gc.parent;
306 struct attribute_group *attr_group;
307 struct attribute **attrs;
310 chip->attr_groups = devm_kcalloc(dev, sizeof(*chip->attr_groups),
311 num_lines + 1, GFP_KERNEL);
312 if (!chip->attr_groups)
315 for (i = 0; i < num_lines; i++) {
316 attr_group = devm_kzalloc(dev, sizeof(*attr_group), GFP_KERNEL);
317 attrs = devm_kcalloc(dev, sizeof(*attrs),
318 GPIO_SIM_NUM_ATTRS, GFP_KERNEL);
319 val_attr = devm_kzalloc(dev, sizeof(*val_attr), GFP_KERNEL);
320 pull_attr = devm_kzalloc(dev, sizeof(*pull_attr), GFP_KERNEL);
321 if (!attr_group || !attrs || !val_attr || !pull_attr)
324 attr_group->name = devm_kasprintf(dev, GFP_KERNEL,
326 if (!attr_group->name)
329 val_attr->offset = pull_attr->offset = i;
331 val_dev_attr = &val_attr->dev_attr;
332 pull_dev_attr = &pull_attr->dev_attr;
334 sysfs_attr_init(&val_dev_attr->attr);
335 sysfs_attr_init(&pull_dev_attr->attr);
337 val_dev_attr->attr.name = "value";
338 pull_dev_attr->attr.name = "pull";
340 val_dev_attr->attr.mode = pull_dev_attr->attr.mode = 0644;
342 val_dev_attr->show = gpio_sim_sysfs_val_show;
343 val_dev_attr->store = gpio_sim_sysfs_val_store;
344 pull_dev_attr->show = gpio_sim_sysfs_pull_show;
345 pull_dev_attr->store = gpio_sim_sysfs_pull_store;
347 attrs[0] = &val_dev_attr->attr;
348 attrs[1] = &pull_dev_attr->attr;
350 attr_group->attrs = attrs;
351 chip->attr_groups[i] = attr_group;
354 ret = sysfs_create_groups(&chip->gc.gpiodev->dev.kobj,
359 return devm_add_action_or_reset(dev, gpio_sim_sysfs_remove, chip);
362 static int gpio_sim_add_bank(struct fwnode_handle *swnode, struct device *dev)
364 struct gpio_sim_chip *chip;
365 struct gpio_chip *gc;
370 ret = fwnode_property_read_u32(swnode, "ngpios", &num_lines);
374 ret = fwnode_property_read_string(swnode, "gpio-sim,label", &label);
376 label = devm_kasprintf(dev, GFP_KERNEL, "%s-%s",
377 dev_name(dev), fwnode_get_name(swnode));
382 chip = devm_kzalloc(dev, sizeof(*chip), GFP_KERNEL);
386 chip->direction_map = devm_bitmap_alloc(dev, num_lines, GFP_KERNEL);
387 if (!chip->direction_map)
390 /* Default to input mode. */
391 bitmap_fill(chip->direction_map, num_lines);
393 chip->value_map = devm_bitmap_zalloc(dev, num_lines, GFP_KERNEL);
394 if (!chip->value_map)
397 chip->pull_map = devm_bitmap_zalloc(dev, num_lines, GFP_KERNEL);
401 chip->irq_sim = devm_irq_domain_create_sim(dev, NULL, num_lines);
402 if (IS_ERR(chip->irq_sim))
403 return PTR_ERR(chip->irq_sim);
405 mutex_init(&chip->lock);
406 ret = devm_add_action_or_reset(dev, gpio_sim_mutex_destroy,
413 gc->ngpio = num_lines;
415 gc->owner = THIS_MODULE;
418 gc->get = gpio_sim_get;
419 gc->set = gpio_sim_set;
420 gc->get_multiple = gpio_sim_get_multiple;
421 gc->set_multiple = gpio_sim_set_multiple;
422 gc->direction_output = gpio_sim_direction_output;
423 gc->direction_input = gpio_sim_direction_input;
424 gc->get_direction = gpio_sim_get_direction;
425 gc->set_config = gpio_sim_set_config;
426 gc->to_irq = gpio_sim_to_irq;
427 gc->free = gpio_sim_free;
429 ret = devm_gpiochip_add_data(dev, gc, chip);
433 /* Used by sysfs and configfs callbacks. */
434 dev_set_drvdata(&gc->gpiodev->dev, chip);
436 return gpio_sim_setup_sysfs(chip);
439 static int gpio_sim_probe(struct platform_device *pdev)
441 struct device *dev = &pdev->dev;
442 struct fwnode_handle *swnode;
445 device_for_each_child_node(dev, swnode) {
446 ret = gpio_sim_add_bank(swnode, dev);
448 fwnode_handle_put(swnode);
456 static const struct of_device_id gpio_sim_of_match[] = {
457 { .compatible = "gpio-simulator" },
460 MODULE_DEVICE_TABLE(of, gpio_sim_of_match);
462 static struct platform_driver gpio_sim_driver = {
465 .of_match_table = gpio_sim_of_match,
467 .probe = gpio_sim_probe,
470 struct gpio_sim_device {
471 struct config_group group;
474 * If pdev is NULL, the device is 'pending' (waiting for configuration).
475 * Once the pointer is assigned, the device has been created and the
478 struct platform_device *pdev;
482 * Each configfs filesystem operation is protected with the subsystem
483 * mutex. Each separate attribute is protected with the buffer mutex.
484 * This structure however can be modified by callbacks of different
485 * attributes so we need another lock.
487 * We use this lock fo protecting all data structures owned by this
493 * This is used to synchronously wait for the driver's probe to complete
494 * and notify the user-space about any errors.
496 struct notifier_block bus_notifier;
497 struct completion probe_completion;
500 struct gpiod_hog *hogs;
502 struct list_head bank_list;
505 /* This is called with dev->lock already taken. */
506 static int gpio_sim_bus_notifier_call(struct notifier_block *nb,
507 unsigned long action, void *data)
509 struct gpio_sim_device *simdev = container_of(nb,
510 struct gpio_sim_device,
512 struct device *dev = data;
515 snprintf(devname, sizeof(devname), "gpio-sim.%u", simdev->id);
517 if (strcmp(dev_name(dev), devname) == 0) {
518 if (action == BUS_NOTIFY_BOUND_DRIVER)
519 simdev->driver_bound = true;
520 else if (action == BUS_NOTIFY_DRIVER_NOT_BOUND)
521 simdev->driver_bound = false;
525 complete(&simdev->probe_completion);
532 static struct gpio_sim_device *to_gpio_sim_device(struct config_item *item)
534 struct config_group *group = to_config_group(item);
536 return container_of(group, struct gpio_sim_device, group);
539 struct gpio_sim_bank {
540 struct config_group group;
543 * We could have used the ci_parent field of the config_item but
544 * configfs is stupid and calls the item's release callback after
545 * already having cleared the parent pointer even though the parent
546 * is guaranteed to survive the child...
548 * So we need to store the pointer to the parent struct here. We can
549 * dereference it anywhere we need with no checks and no locking as
550 * it's guaranteed to survive the childred and protected by configfs
553 * Same for other structures.
555 struct gpio_sim_device *parent;
556 struct list_head siblings;
559 unsigned int num_lines;
561 struct list_head line_list;
563 struct fwnode_handle *swnode;
566 static struct gpio_sim_bank *to_gpio_sim_bank(struct config_item *item)
568 struct config_group *group = to_config_group(item);
570 return container_of(group, struct gpio_sim_bank, group);
573 static struct gpio_sim_device *
574 gpio_sim_bank_get_device(struct gpio_sim_bank *bank)
581 struct gpio_sim_line {
582 struct config_group group;
584 struct gpio_sim_bank *parent;
585 struct list_head siblings;
590 /* There can only be one hog per line. */
591 struct gpio_sim_hog *hog;
594 static struct gpio_sim_line *to_gpio_sim_line(struct config_item *item)
596 struct config_group *group = to_config_group(item);
598 return container_of(group, struct gpio_sim_line, group);
601 static struct gpio_sim_device *
602 gpio_sim_line_get_device(struct gpio_sim_line *line)
604 struct gpio_sim_bank *bank = line->parent;
606 return gpio_sim_bank_get_device(bank);
609 struct gpio_sim_hog {
610 struct config_item item;
611 struct gpio_sim_line *parent;
617 static struct gpio_sim_hog *to_gpio_sim_hog(struct config_item *item)
619 return container_of(item, struct gpio_sim_hog, item);
622 static struct gpio_sim_device *gpio_sim_hog_get_device(struct gpio_sim_hog *hog)
624 struct gpio_sim_line *line = hog->parent;
626 return gpio_sim_line_get_device(line);
629 static bool gpio_sim_device_is_live_unlocked(struct gpio_sim_device *dev)
634 static char *gpio_sim_strdup_trimmed(const char *str, size_t count)
638 dup = kstrndup(str, count, GFP_KERNEL);
642 trimmed = strstrip(dup);
643 memmove(dup, trimmed, strlen(trimmed) + 1);
648 static ssize_t gpio_sim_device_config_dev_name_show(struct config_item *item,
651 struct gpio_sim_device *dev = to_gpio_sim_device(item);
652 struct platform_device *pdev;
655 mutex_lock(&dev->lock);
658 ret = sprintf(page, "%s\n", dev_name(&pdev->dev));
660 ret = sprintf(page, "gpio-sim.%d\n", dev->id);
661 mutex_unlock(&dev->lock);
666 CONFIGFS_ATTR_RO(gpio_sim_device_config_, dev_name);
669 gpio_sim_device_config_live_show(struct config_item *item, char *page)
671 struct gpio_sim_device *dev = to_gpio_sim_device(item);
674 mutex_lock(&dev->lock);
675 live = gpio_sim_device_is_live_unlocked(dev);
676 mutex_unlock(&dev->lock);
678 return sprintf(page, "%c\n", live ? '1' : '0');
681 static char **gpio_sim_make_line_names(struct gpio_sim_bank *bank,
682 unsigned int *line_names_size)
684 unsigned int max_offset = 0;
685 bool has_line_names = false;
686 struct gpio_sim_line *line;
689 list_for_each_entry(line, &bank->line_list, siblings) {
691 if (line->offset > max_offset)
692 max_offset = line->offset;
695 * max_offset can stay at 0 so it's not an indicator
696 * of whether line names were configured at all.
698 has_line_names = true;
704 * This is not an error - NULL means, there are no line
709 *line_names_size = max_offset + 1;
711 line_names = kcalloc(*line_names_size, sizeof(*line_names), GFP_KERNEL);
713 return ERR_PTR(-ENOMEM);
715 list_for_each_entry(line, &bank->line_list, siblings)
716 line_names[line->offset] = line->name;
721 static void gpio_sim_remove_hogs(struct gpio_sim_device *dev)
723 struct gpiod_hog *hog;
728 gpiod_remove_hogs(dev->hogs);
730 for (hog = dev->hogs; !hog->chip_label; hog++) {
731 kfree(hog->chip_label);
732 kfree(hog->line_name);
739 static int gpio_sim_add_hogs(struct gpio_sim_device *dev)
741 unsigned int num_hogs = 0, idx = 0;
742 struct gpio_sim_bank *bank;
743 struct gpio_sim_line *line;
744 struct gpiod_hog *hog;
746 list_for_each_entry(bank, &dev->bank_list, siblings) {
747 list_for_each_entry(line, &bank->line_list, siblings) {
756 /* Allocate one more for the sentinel. */
757 dev->hogs = kcalloc(num_hogs + 1, sizeof(*dev->hogs), GFP_KERNEL);
761 list_for_each_entry(bank, &dev->bank_list, siblings) {
762 list_for_each_entry(line, &bank->line_list, siblings) {
766 hog = &dev->hogs[idx++];
769 * We need to make this string manually because at this
770 * point the device doesn't exist yet and so dev_name()
773 hog->chip_label = kasprintf(GFP_KERNEL,
774 "gpio-sim.%u-%s", dev->id,
775 fwnode_get_name(bank->swnode));
776 if (!hog->chip_label) {
777 gpio_sim_remove_hogs(dev);
782 * We need to duplicate this because the hog config
783 * item can be removed at any time (and we can't block
784 * it) and gpiolib doesn't make a deep copy of the hog
787 if (line->hog->name) {
788 hog->line_name = kstrdup(line->hog->name,
790 if (!hog->line_name) {
791 gpio_sim_remove_hogs(dev);
796 hog->chip_hwnum = line->offset;
797 hog->dflags = line->hog->dir;
801 gpiod_add_hogs(dev->hogs);
806 static struct fwnode_handle *
807 gpio_sim_make_bank_swnode(struct gpio_sim_bank *bank,
808 struct fwnode_handle *parent)
810 struct property_entry properties[GPIO_SIM_PROP_MAX];
811 unsigned int prop_idx = 0, line_names_size = 0;
812 struct fwnode_handle *swnode;
815 memset(properties, 0, sizeof(properties));
817 properties[prop_idx++] = PROPERTY_ENTRY_U32("ngpios", bank->num_lines);
819 if (bank->label && (strlen(bank->label) > 0))
820 properties[prop_idx++] = PROPERTY_ENTRY_STRING("gpio-sim,label",
823 line_names = gpio_sim_make_line_names(bank, &line_names_size);
824 if (IS_ERR(line_names))
825 return ERR_CAST(line_names);
828 properties[prop_idx++] = PROPERTY_ENTRY_STRING_ARRAY_LEN(
830 line_names, line_names_size);
832 swnode = fwnode_create_software_node(properties, parent);
837 static void gpio_sim_remove_swnode_recursive(struct fwnode_handle *swnode)
839 struct fwnode_handle *child;
841 fwnode_for_each_child_node(swnode, child)
842 fwnode_remove_software_node(child);
844 fwnode_remove_software_node(swnode);
847 static bool gpio_sim_bank_labels_non_unique(struct gpio_sim_device *dev)
849 struct gpio_sim_bank *this, *pos;
851 list_for_each_entry(this, &dev->bank_list, siblings) {
852 list_for_each_entry(pos, &dev->bank_list, siblings) {
853 if (this == pos || (!this->label || !pos->label))
856 if (strcmp(this->label, pos->label) == 0)
864 static int gpio_sim_device_activate_unlocked(struct gpio_sim_device *dev)
866 struct platform_device_info pdevinfo;
867 struct fwnode_handle *swnode;
868 struct platform_device *pdev;
869 struct gpio_sim_bank *bank;
872 if (list_empty(&dev->bank_list))
876 * Non-unique GPIO device labels are a corner-case we don't support
877 * as it would interfere with machine hogging mechanism and has little
880 if (gpio_sim_bank_labels_non_unique(dev))
883 memset(&pdevinfo, 0, sizeof(pdevinfo));
885 swnode = fwnode_create_software_node(NULL, NULL);
887 return PTR_ERR(swnode);
889 list_for_each_entry(bank, &dev->bank_list, siblings) {
890 bank->swnode = gpio_sim_make_bank_swnode(bank, swnode);
891 if (IS_ERR(bank->swnode)) {
892 ret = PTR_ERR(bank->swnode);
893 gpio_sim_remove_swnode_recursive(swnode);
898 ret = gpio_sim_add_hogs(dev);
900 gpio_sim_remove_swnode_recursive(swnode);
904 pdevinfo.name = "gpio-sim";
905 pdevinfo.fwnode = swnode;
906 pdevinfo.id = dev->id;
908 reinit_completion(&dev->probe_completion);
909 dev->driver_bound = false;
910 bus_register_notifier(&platform_bus_type, &dev->bus_notifier);
912 pdev = platform_device_register_full(&pdevinfo);
914 bus_unregister_notifier(&platform_bus_type, &dev->bus_notifier);
915 gpio_sim_remove_hogs(dev);
916 gpio_sim_remove_swnode_recursive(swnode);
917 return PTR_ERR(pdev);
920 wait_for_completion(&dev->probe_completion);
921 bus_unregister_notifier(&platform_bus_type, &dev->bus_notifier);
923 if (!dev->driver_bound) {
924 /* Probe failed, check kernel log. */
925 platform_device_unregister(pdev);
926 gpio_sim_remove_hogs(dev);
927 gpio_sim_remove_swnode_recursive(swnode);
936 static void gpio_sim_device_deactivate_unlocked(struct gpio_sim_device *dev)
938 struct fwnode_handle *swnode;
940 swnode = dev_fwnode(&dev->pdev->dev);
941 platform_device_unregister(dev->pdev);
942 gpio_sim_remove_swnode_recursive(swnode);
944 gpio_sim_remove_hogs(dev);
948 gpio_sim_device_config_live_store(struct config_item *item,
949 const char *page, size_t count)
951 struct gpio_sim_device *dev = to_gpio_sim_device(item);
955 ret = kstrtobool(page, &live);
959 mutex_lock(&dev->lock);
961 if ((!live && !gpio_sim_device_is_live_unlocked(dev)) ||
962 (live && gpio_sim_device_is_live_unlocked(dev)))
965 ret = gpio_sim_device_activate_unlocked(dev);
967 gpio_sim_device_deactivate_unlocked(dev);
969 mutex_unlock(&dev->lock);
974 CONFIGFS_ATTR(gpio_sim_device_config_, live);
976 static struct configfs_attribute *gpio_sim_device_config_attrs[] = {
977 &gpio_sim_device_config_attr_dev_name,
978 &gpio_sim_device_config_attr_live,
982 struct gpio_sim_chip_name_ctx {
983 struct gpio_sim_device *dev;
987 static int gpio_sim_emit_chip_name(struct device *dev, void *data)
989 struct gpio_sim_chip_name_ctx *ctx = data;
990 struct fwnode_handle *swnode;
991 struct gpio_sim_bank *bank;
993 /* This would be the sysfs device exported in /sys/class/gpio. */
997 swnode = dev_fwnode(dev);
999 list_for_each_entry(bank, &ctx->dev->bank_list, siblings) {
1000 if (bank->swnode == swnode)
1001 return sprintf(ctx->page, "%s\n", dev_name(dev));
1007 static ssize_t gpio_sim_bank_config_chip_name_show(struct config_item *item,
1010 struct gpio_sim_bank *bank = to_gpio_sim_bank(item);
1011 struct gpio_sim_device *dev = gpio_sim_bank_get_device(bank);
1012 struct gpio_sim_chip_name_ctx ctx = { dev, page };
1015 mutex_lock(&dev->lock);
1016 if (gpio_sim_device_is_live_unlocked(dev))
1017 ret = device_for_each_child(&dev->pdev->dev, &ctx,
1018 gpio_sim_emit_chip_name);
1020 ret = sprintf(page, "none\n");
1021 mutex_unlock(&dev->lock);
1026 CONFIGFS_ATTR_RO(gpio_sim_bank_config_, chip_name);
1029 gpio_sim_bank_config_label_show(struct config_item *item, char *page)
1031 struct gpio_sim_bank *bank = to_gpio_sim_bank(item);
1032 struct gpio_sim_device *dev = gpio_sim_bank_get_device(bank);
1035 mutex_lock(&dev->lock);
1036 ret = sprintf(page, "%s\n", bank->label ?: "");
1037 mutex_unlock(&dev->lock);
1042 static ssize_t gpio_sim_bank_config_label_store(struct config_item *item,
1043 const char *page, size_t count)
1045 struct gpio_sim_bank *bank = to_gpio_sim_bank(item);
1046 struct gpio_sim_device *dev = gpio_sim_bank_get_device(bank);
1049 mutex_lock(&dev->lock);
1051 if (gpio_sim_device_is_live_unlocked(dev)) {
1052 mutex_unlock(&dev->lock);
1056 trimmed = gpio_sim_strdup_trimmed(page, count);
1058 mutex_unlock(&dev->lock);
1063 bank->label = trimmed;
1065 mutex_unlock(&dev->lock);
1069 CONFIGFS_ATTR(gpio_sim_bank_config_, label);
1072 gpio_sim_bank_config_num_lines_show(struct config_item *item, char *page)
1074 struct gpio_sim_bank *bank = to_gpio_sim_bank(item);
1075 struct gpio_sim_device *dev = gpio_sim_bank_get_device(bank);
1078 mutex_lock(&dev->lock);
1079 ret = sprintf(page, "%u\n", bank->num_lines);
1080 mutex_unlock(&dev->lock);
1086 gpio_sim_bank_config_num_lines_store(struct config_item *item,
1087 const char *page, size_t count)
1089 struct gpio_sim_bank *bank = to_gpio_sim_bank(item);
1090 struct gpio_sim_device *dev = gpio_sim_bank_get_device(bank);
1091 unsigned int num_lines;
1094 ret = kstrtouint(page, 0, &num_lines);
1101 mutex_lock(&dev->lock);
1103 if (gpio_sim_device_is_live_unlocked(dev)) {
1104 mutex_unlock(&dev->lock);
1108 bank->num_lines = num_lines;
1110 mutex_unlock(&dev->lock);
1114 CONFIGFS_ATTR(gpio_sim_bank_config_, num_lines);
1116 static struct configfs_attribute *gpio_sim_bank_config_attrs[] = {
1117 &gpio_sim_bank_config_attr_chip_name,
1118 &gpio_sim_bank_config_attr_label,
1119 &gpio_sim_bank_config_attr_num_lines,
1124 gpio_sim_line_config_name_show(struct config_item *item, char *page)
1126 struct gpio_sim_line *line = to_gpio_sim_line(item);
1127 struct gpio_sim_device *dev = gpio_sim_line_get_device(line);
1130 mutex_lock(&dev->lock);
1131 ret = sprintf(page, "%s\n", line->name ?: "");
1132 mutex_unlock(&dev->lock);
1137 static ssize_t gpio_sim_line_config_name_store(struct config_item *item,
1138 const char *page, size_t count)
1140 struct gpio_sim_line *line = to_gpio_sim_line(item);
1141 struct gpio_sim_device *dev = gpio_sim_line_get_device(line);
1144 mutex_lock(&dev->lock);
1146 if (gpio_sim_device_is_live_unlocked(dev)) {
1147 mutex_unlock(&dev->lock);
1151 trimmed = gpio_sim_strdup_trimmed(page, count);
1153 mutex_unlock(&dev->lock);
1158 line->name = trimmed;
1160 mutex_unlock(&dev->lock);
1165 CONFIGFS_ATTR(gpio_sim_line_config_, name);
1167 static struct configfs_attribute *gpio_sim_line_config_attrs[] = {
1168 &gpio_sim_line_config_attr_name,
1172 static ssize_t gpio_sim_hog_config_name_show(struct config_item *item,
1175 struct gpio_sim_hog *hog = to_gpio_sim_hog(item);
1176 struct gpio_sim_device *dev = gpio_sim_hog_get_device(hog);
1179 mutex_lock(&dev->lock);
1180 ret = sprintf(page, "%s\n", hog->name ?: "");
1181 mutex_unlock(&dev->lock);
1186 static ssize_t gpio_sim_hog_config_name_store(struct config_item *item,
1187 const char *page, size_t count)
1189 struct gpio_sim_hog *hog = to_gpio_sim_hog(item);
1190 struct gpio_sim_device *dev = gpio_sim_hog_get_device(hog);
1193 mutex_lock(&dev->lock);
1195 if (gpio_sim_device_is_live_unlocked(dev)) {
1196 mutex_unlock(&dev->lock);
1200 trimmed = gpio_sim_strdup_trimmed(page, count);
1202 mutex_unlock(&dev->lock);
1207 hog->name = trimmed;
1209 mutex_unlock(&dev->lock);
1214 CONFIGFS_ATTR(gpio_sim_hog_config_, name);
1216 static ssize_t gpio_sim_hog_config_direction_show(struct config_item *item,
1219 struct gpio_sim_hog *hog = to_gpio_sim_hog(item);
1220 struct gpio_sim_device *dev = gpio_sim_hog_get_device(hog);
1224 mutex_lock(&dev->lock);
1226 mutex_unlock(&dev->lock);
1232 case GPIOD_OUT_HIGH:
1233 repr = "output-high";
1236 repr = "output-low";
1239 /* This would be a programmer bug. */
1240 WARN(1, "Unexpected hog direction value: %d", dir);
1244 return sprintf(page, "%s\n", repr);
1248 gpio_sim_hog_config_direction_store(struct config_item *item,
1249 const char *page, size_t count)
1251 struct gpio_sim_hog *hog = to_gpio_sim_hog(item);
1252 struct gpio_sim_device *dev = gpio_sim_hog_get_device(hog);
1256 mutex_lock(&dev->lock);
1258 if (gpio_sim_device_is_live_unlocked(dev)) {
1259 mutex_unlock(&dev->lock);
1263 trimmed = gpio_sim_strdup_trimmed(page, count);
1265 mutex_unlock(&dev->lock);
1269 if (strcmp(trimmed, "input") == 0)
1271 else if (strcmp(trimmed, "output-high") == 0)
1272 dir = GPIOD_OUT_HIGH;
1273 else if (strcmp(trimmed, "output-low") == 0)
1274 dir = GPIOD_OUT_LOW;
1281 mutex_unlock(&dev->lock);
1287 mutex_unlock(&dev->lock);
1292 CONFIGFS_ATTR(gpio_sim_hog_config_, direction);
1294 static struct configfs_attribute *gpio_sim_hog_config_attrs[] = {
1295 &gpio_sim_hog_config_attr_name,
1296 &gpio_sim_hog_config_attr_direction,
1300 static void gpio_sim_hog_config_item_release(struct config_item *item)
1302 struct gpio_sim_hog *hog = to_gpio_sim_hog(item);
1303 struct gpio_sim_line *line = hog->parent;
1304 struct gpio_sim_device *dev = gpio_sim_hog_get_device(hog);
1306 mutex_lock(&dev->lock);
1308 mutex_unlock(&dev->lock);
1314 struct configfs_item_operations gpio_sim_hog_config_item_ops = {
1315 .release = gpio_sim_hog_config_item_release,
1318 static const struct config_item_type gpio_sim_hog_config_type = {
1319 .ct_item_ops = &gpio_sim_hog_config_item_ops,
1320 .ct_attrs = gpio_sim_hog_config_attrs,
1321 .ct_owner = THIS_MODULE,
1324 static struct config_item *
1325 gpio_sim_line_config_make_hog_item(struct config_group *group, const char *name)
1327 struct gpio_sim_line *line = to_gpio_sim_line(&group->cg_item);
1328 struct gpio_sim_device *dev = gpio_sim_line_get_device(line);
1329 struct gpio_sim_hog *hog;
1331 if (strcmp(name, "hog") != 0)
1332 return ERR_PTR(-EINVAL);
1334 mutex_lock(&dev->lock);
1336 hog = kzalloc(sizeof(*hog), GFP_KERNEL);
1338 mutex_unlock(&dev->lock);
1339 return ERR_PTR(-ENOMEM);
1342 config_item_init_type_name(&hog->item, name,
1343 &gpio_sim_hog_config_type);
1345 hog->dir = GPIOD_IN;
1350 mutex_unlock(&dev->lock);
1355 static void gpio_sim_line_config_group_release(struct config_item *item)
1357 struct gpio_sim_line *line = to_gpio_sim_line(item);
1358 struct gpio_sim_device *dev = gpio_sim_line_get_device(line);
1360 mutex_lock(&dev->lock);
1361 list_del(&line->siblings);
1362 mutex_unlock(&dev->lock);
1368 static struct configfs_item_operations gpio_sim_line_config_item_ops = {
1369 .release = gpio_sim_line_config_group_release,
1372 static struct configfs_group_operations gpio_sim_line_config_group_ops = {
1373 .make_item = gpio_sim_line_config_make_hog_item,
1376 static const struct config_item_type gpio_sim_line_config_type = {
1377 .ct_item_ops = &gpio_sim_line_config_item_ops,
1378 .ct_group_ops = &gpio_sim_line_config_group_ops,
1379 .ct_attrs = gpio_sim_line_config_attrs,
1380 .ct_owner = THIS_MODULE,
1383 static struct config_group *
1384 gpio_sim_bank_config_make_line_group(struct config_group *group,
1387 struct gpio_sim_bank *bank = to_gpio_sim_bank(&group->cg_item);
1388 struct gpio_sim_device *dev = gpio_sim_bank_get_device(bank);
1389 struct gpio_sim_line *line;
1390 unsigned int offset;
1393 ret = sscanf(name, "line%u%n", &offset, &nchar);
1394 if (ret != 1 || nchar != strlen(name))
1395 return ERR_PTR(-EINVAL);
1397 mutex_lock(&dev->lock);
1399 if (gpio_sim_device_is_live_unlocked(dev)) {
1400 mutex_unlock(&dev->lock);
1401 return ERR_PTR(-EBUSY);
1404 line = kzalloc(sizeof(*line), GFP_KERNEL);
1406 mutex_unlock(&dev->lock);
1407 return ERR_PTR(-ENOMEM);
1410 config_group_init_type_name(&line->group, name,
1411 &gpio_sim_line_config_type);
1413 line->parent = bank;
1414 line->offset = offset;
1415 list_add_tail(&line->siblings, &bank->line_list);
1417 mutex_unlock(&dev->lock);
1419 return &line->group;
1422 static void gpio_sim_bank_config_group_release(struct config_item *item)
1424 struct gpio_sim_bank *bank = to_gpio_sim_bank(item);
1425 struct gpio_sim_device *dev = gpio_sim_bank_get_device(bank);
1427 mutex_lock(&dev->lock);
1428 list_del(&bank->siblings);
1429 mutex_unlock(&dev->lock);
1435 static struct configfs_item_operations gpio_sim_bank_config_item_ops = {
1436 .release = gpio_sim_bank_config_group_release,
1439 static struct configfs_group_operations gpio_sim_bank_config_group_ops = {
1440 .make_group = gpio_sim_bank_config_make_line_group,
1443 static const struct config_item_type gpio_sim_bank_config_group_type = {
1444 .ct_item_ops = &gpio_sim_bank_config_item_ops,
1445 .ct_group_ops = &gpio_sim_bank_config_group_ops,
1446 .ct_attrs = gpio_sim_bank_config_attrs,
1447 .ct_owner = THIS_MODULE,
1450 static struct config_group *
1451 gpio_sim_device_config_make_bank_group(struct config_group *group,
1454 struct gpio_sim_device *dev = to_gpio_sim_device(&group->cg_item);
1455 struct gpio_sim_bank *bank;
1457 mutex_lock(&dev->lock);
1459 if (gpio_sim_device_is_live_unlocked(dev)) {
1460 mutex_unlock(&dev->lock);
1461 return ERR_PTR(-EBUSY);
1464 bank = kzalloc(sizeof(*bank), GFP_KERNEL);
1466 mutex_unlock(&dev->lock);
1467 return ERR_PTR(-ENOMEM);
1470 config_group_init_type_name(&bank->group, name,
1471 &gpio_sim_bank_config_group_type);
1472 bank->num_lines = 1;
1474 INIT_LIST_HEAD(&bank->line_list);
1475 list_add_tail(&bank->siblings, &dev->bank_list);
1477 mutex_unlock(&dev->lock);
1479 return &bank->group;
1482 static void gpio_sim_device_config_group_release(struct config_item *item)
1484 struct gpio_sim_device *dev = to_gpio_sim_device(item);
1486 mutex_lock(&dev->lock);
1487 if (gpio_sim_device_is_live_unlocked(dev))
1488 gpio_sim_device_deactivate_unlocked(dev);
1489 mutex_unlock(&dev->lock);
1491 mutex_destroy(&dev->lock);
1492 ida_free(&gpio_sim_ida, dev->id);
1496 static struct configfs_item_operations gpio_sim_device_config_item_ops = {
1497 .release = gpio_sim_device_config_group_release,
1500 static struct configfs_group_operations gpio_sim_device_config_group_ops = {
1501 .make_group = gpio_sim_device_config_make_bank_group,
1504 static const struct config_item_type gpio_sim_device_config_group_type = {
1505 .ct_item_ops = &gpio_sim_device_config_item_ops,
1506 .ct_group_ops = &gpio_sim_device_config_group_ops,
1507 .ct_attrs = gpio_sim_device_config_attrs,
1508 .ct_owner = THIS_MODULE,
1511 static struct config_group *
1512 gpio_sim_config_make_device_group(struct config_group *group, const char *name)
1514 struct gpio_sim_device *dev;
1517 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
1519 return ERR_PTR(-ENOMEM);
1521 id = ida_alloc(&gpio_sim_ida, GFP_KERNEL);
1527 config_group_init_type_name(&dev->group, name,
1528 &gpio_sim_device_config_group_type);
1530 mutex_init(&dev->lock);
1531 INIT_LIST_HEAD(&dev->bank_list);
1533 dev->bus_notifier.notifier_call = gpio_sim_bus_notifier_call;
1534 init_completion(&dev->probe_completion);
1539 static struct configfs_group_operations gpio_sim_config_group_ops = {
1540 .make_group = gpio_sim_config_make_device_group,
1543 static const struct config_item_type gpio_sim_config_type = {
1544 .ct_group_ops = &gpio_sim_config_group_ops,
1545 .ct_owner = THIS_MODULE,
1548 static struct configfs_subsystem gpio_sim_config_subsys = {
1551 .ci_namebuf = "gpio-sim",
1552 .ci_type = &gpio_sim_config_type,
1557 static int __init gpio_sim_init(void)
1561 ret = platform_driver_register(&gpio_sim_driver);
1563 pr_err("Error %d while registering the platform driver\n", ret);
1567 config_group_init(&gpio_sim_config_subsys.su_group);
1568 mutex_init(&gpio_sim_config_subsys.su_mutex);
1569 ret = configfs_register_subsystem(&gpio_sim_config_subsys);
1571 pr_err("Error %d while registering the configfs subsystem %s\n",
1572 ret, gpio_sim_config_subsys.su_group.cg_item.ci_namebuf);
1573 mutex_destroy(&gpio_sim_config_subsys.su_mutex);
1574 platform_driver_unregister(&gpio_sim_driver);
1580 module_init(gpio_sim_init);
1582 static void __exit gpio_sim_exit(void)
1584 configfs_unregister_subsystem(&gpio_sim_config_subsys);
1585 mutex_destroy(&gpio_sim_config_subsys.su_mutex);
1586 platform_driver_unregister(&gpio_sim_driver);
1588 module_exit(gpio_sim_exit);
1590 MODULE_AUTHOR("Bartosz Golaszewski <brgl@bgdev.pl");
1591 MODULE_DESCRIPTION("GPIO Simulator Module");
1592 MODULE_LICENSE("GPL");