diff options
Diffstat (limited to 'drivers/gpio/gpio-sim.c')
| -rw-r--r-- | drivers/gpio/gpio-sim.c | 1592 |
1 files changed, 1592 insertions, 0 deletions
diff --git a/drivers/gpio/gpio-sim.c b/drivers/gpio/gpio-sim.c new file mode 100644 index 000000000000..04b137eca8da --- /dev/null +++ b/drivers/gpio/gpio-sim.c @@ -0,0 +1,1592 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * GPIO testing driver based on configfs. + * + * Copyright (C) 2021 Bartosz Golaszewski <brgl@bgdev.pl> + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include <linux/bitmap.h> +#include <linux/completion.h> +#include <linux/configfs.h> +#include <linux/device.h> +#include <linux/gpio/driver.h> +#include <linux/gpio/machine.h> +#include <linux/idr.h> +#include <linux/interrupt.h> +#include <linux/irq.h> +#include <linux/irq_sim.h> +#include <linux/list.h> +#include <linux/mod_devicetable.h> +#include <linux/module.h> +#include <linux/mutex.h> +#include <linux/notifier.h> +#include <linux/platform_device.h> +#include <linux/property.h> +#include <linux/slab.h> +#include <linux/string.h> +#include <linux/string_helpers.h> +#include <linux/sysfs.h> + +#include "gpiolib.h" + +#define GPIO_SIM_PROP_MAX 4 /* Max 3 properties + sentinel. */ +#define GPIO_SIM_NUM_ATTRS 3 /* value, pull and sentinel */ + +static DEFINE_IDA(gpio_sim_ida); + +struct gpio_sim_chip { + struct gpio_chip gc; + unsigned long *direction_map; + unsigned long *value_map; + unsigned long *pull_map; + struct irq_domain *irq_sim; + struct mutex lock; + const struct attribute_group **attr_groups; +}; + +struct gpio_sim_attribute { + struct device_attribute dev_attr; + unsigned int offset; +}; + +static struct gpio_sim_attribute * +to_gpio_sim_attr(struct device_attribute *dev_attr) +{ + return container_of(dev_attr, struct gpio_sim_attribute, dev_attr); +} + +static int gpio_sim_apply_pull(struct gpio_sim_chip *chip, + unsigned int offset, int value) +{ + int irq, irq_type, ret; + struct gpio_desc *desc; + struct gpio_chip *gc; + + gc = &chip->gc; + desc = &gc->gpiodev->descs[offset]; + + mutex_lock(&chip->lock); + + if (test_bit(FLAG_REQUESTED, &desc->flags) && + !test_bit(FLAG_IS_OUT, &desc->flags)) { + if (value == !!test_bit(offset, chip->value_map)) + goto set_pull; + + /* + * This is fine - it just means, nobody is listening + * for interrupts on this line, otherwise + * irq_create_mapping() would have been called from + * the to_irq() callback. + */ + irq = irq_find_mapping(chip->irq_sim, offset); + if (!irq) + goto set_value; + + irq_type = irq_get_trigger_type(irq); + + if ((value && (irq_type & IRQ_TYPE_EDGE_RISING)) || + (!value && (irq_type & IRQ_TYPE_EDGE_FALLING))) { + ret = irq_set_irqchip_state(irq, IRQCHIP_STATE_PENDING, + true); + if (ret) + goto set_pull; + } + } + +set_value: + /* Change the value unless we're actively driving the line. */ + if (!test_bit(FLAG_REQUESTED, &desc->flags) || + !test_bit(FLAG_IS_OUT, &desc->flags)) + __assign_bit(offset, chip->value_map, value); + +set_pull: + __assign_bit(offset, chip->pull_map, value); + mutex_unlock(&chip->lock); + return 0; +} + +static int gpio_sim_get(struct gpio_chip *gc, unsigned int offset) +{ + struct gpio_sim_chip *chip = gpiochip_get_data(gc); + int ret; + + mutex_lock(&chip->lock); + ret = !!test_bit(offset, chip->value_map); + mutex_unlock(&chip->lock); + + return ret; +} + +static void gpio_sim_set(struct gpio_chip *gc, unsigned int offset, int value) +{ + struct gpio_sim_chip *chip = gpiochip_get_data(gc); + + mutex_lock(&chip->lock); + __assign_bit(offset, chip->value_map, value); + mutex_unlock(&chip->lock); +} + +static int gpio_sim_get_multiple(struct gpio_chip *gc, + unsigned long *mask, unsigned long *bits) +{ + struct gpio_sim_chip *chip = gpiochip_get_data(gc); + + mutex_lock(&chip->lock); + bitmap_copy(bits, chip->value_map, gc->ngpio); + mutex_unlock(&chip->lock); + + return 0; +} + +static void gpio_sim_set_multiple(struct gpio_chip *gc, + unsigned long *mask, unsigned long *bits) +{ + struct gpio_sim_chip *chip = gpiochip_get_data(gc); + + mutex_lock(&chip->lock); + bitmap_copy(chip->value_map, bits, gc->ngpio); + mutex_unlock(&chip->lock); +} + +static int gpio_sim_direction_output(struct gpio_chip *gc, + unsigned int offset, int value) +{ + struct gpio_sim_chip *chip = gpiochip_get_data(gc); + + mutex_lock(&chip->lock); + __clear_bit(offset, chip->direction_map); + __assign_bit(offset, chip->value_map, value); + mutex_unlock(&chip->lock); + + return 0; +} + +static int gpio_sim_direction_input(struct gpio_chip *gc, unsigned int offset) +{ + struct gpio_sim_chip *chip = gpiochip_get_data(gc); + + mutex_lock(&chip->lock); + __set_bit(offset, chip->direction_map); + mutex_unlock(&chip->lock); + + return 0; +} + +static int gpio_sim_get_direction(struct gpio_chip *gc, unsigned int offset) +{ + struct gpio_sim_chip *chip = gpiochip_get_data(gc); + int direction; + + mutex_lock(&chip->lock); + direction = !!test_bit(offset, chip->direction_map); + mutex_unlock(&chip->lock); + + return direction ? GPIO_LINE_DIRECTION_IN : GPIO_LINE_DIRECTION_OUT; +} + +static int gpio_sim_set_config(struct gpio_chip *gc, + unsigned int offset, unsigned long config) +{ + struct gpio_sim_chip *chip = gpiochip_get_data(gc); + + switch (pinconf_to_config_param(config)) { + case PIN_CONFIG_BIAS_PULL_UP: + return gpio_sim_apply_pull(chip, offset, 1); + case PIN_CONFIG_BIAS_PULL_DOWN: + return gpio_sim_apply_pull(chip, offset, 0); + default: + break; + } + + return -ENOTSUPP; +} + +static int gpio_sim_to_irq(struct gpio_chip *gc, unsigned int offset) +{ + struct gpio_sim_chip *chip = gpiochip_get_data(gc); + + return irq_create_mapping(chip->irq_sim, offset); +} + +static void gpio_sim_free(struct gpio_chip *gc, unsigned int offset) +{ + struct gpio_sim_chip *chip = gpiochip_get_data(gc); + + mutex_lock(&chip->lock); + __assign_bit(offset, chip->value_map, !!test_bit(offset, chip->pull_map)); + mutex_unlock(&chip->lock); +} + +static ssize_t gpio_sim_sysfs_val_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct gpio_sim_attribute *line_attr = to_gpio_sim_attr(attr); + struct gpio_sim_chip *chip = dev_get_drvdata(dev); + int val; + + mutex_lock(&chip->lock); + val = !!test_bit(line_attr->offset, chip->value_map); + mutex_unlock(&chip->lock); + + return sysfs_emit(buf, "%d\n", val); +} + +static ssize_t gpio_sim_sysfs_val_store(struct device *dev, + struct device_attribute *attr, + const char *buf, size_t count) +{ + /* + * Not assigning this function will result in write() returning -EIO + * which is confusing. Return -EPERM explicitly. + */ + return -EPERM; +} + +static const char *const gpio_sim_sysfs_pull_strings[] = { + [0] = "pull-down", + [1] = "pull-up", +}; + +static ssize_t gpio_sim_sysfs_pull_show(struct device *dev, + struct device_attribute *attr, + char *buf) +{ + struct gpio_sim_attribute *line_attr = to_gpio_sim_attr(attr); + struct gpio_sim_chip *chip = dev_get_drvdata(dev); + int pull; + + mutex_lock(&chip->lock); + pull = !!test_bit(line_attr->offset, chip->pull_map); + mutex_unlock(&chip->lock); + + return sysfs_emit(buf, "%s\n", gpio_sim_sysfs_pull_strings[pull]); +} + +static ssize_t gpio_sim_sysfs_pull_store(struct device *dev, + struct device_attribute *attr, + const char *buf, size_t len) +{ + struct gpio_sim_attribute *line_attr = to_gpio_sim_attr(attr); + struct gpio_sim_chip *chip = dev_get_drvdata(dev); + int ret, pull; + + pull = sysfs_match_string(gpio_sim_sysfs_pull_strings, buf); + if (pull < 0) + return pull; + + ret = gpio_sim_apply_pull(chip, line_attr->offset, pull); + if (ret) + return ret; + + return len; +} + +static void gpio_sim_mutex_destroy(void *data) +{ + struct mutex *lock = data; + + mutex_destroy(lock); +} + +static void gpio_sim_sysfs_remove(void *data) +{ + struct gpio_sim_chip *chip = data; + + sysfs_remove_groups(&chip->gc.gpiodev->dev.kobj, chip->attr_groups); +} + +static int gpio_sim_setup_sysfs(struct gpio_sim_chip *chip) +{ + struct device_attribute *val_dev_attr, *pull_dev_attr; + struct gpio_sim_attribute *val_attr, *pull_attr; + unsigned int num_lines = chip->gc.ngpio; + struct device *dev = chip->gc.parent; + struct attribute_group *attr_group; + struct attribute **attrs; + int i, ret; + + chip->attr_groups = devm_kcalloc(dev, sizeof(*chip->attr_groups), + num_lines + 1, GFP_KERNEL); + if (!chip->attr_groups) + return -ENOMEM; + + for (i = 0; i < num_lines; i++) { + attr_group = devm_kzalloc(dev, sizeof(*attr_group), GFP_KERNEL); + attrs = devm_kcalloc(dev, sizeof(*attrs), + GPIO_SIM_NUM_ATTRS, GFP_KERNEL); + val_attr = devm_kzalloc(dev, sizeof(*val_attr), GFP_KERNEL); + pull_attr = devm_kzalloc(dev, sizeof(*pull_attr), GFP_KERNEL); + if (!attr_group || !attrs || !val_attr || !pull_attr) + return -ENOMEM; + + attr_group->name = devm_kasprintf(dev, GFP_KERNEL, + "sim_gpio%u", i); + if (!attr_group->name) + return -ENOMEM; + + val_attr->offset = pull_attr->offset = i; + + val_dev_attr = &val_attr->dev_attr; + pull_dev_attr = &pull_attr->dev_attr; + + sysfs_attr_init(&val_dev_attr->attr); + sysfs_attr_init(&pull_dev_attr->attr); + + val_dev_attr->attr.name = "value"; + pull_dev_attr->attr.name = "pull"; + + val_dev_attr->attr.mode = pull_dev_attr->attr.mode = 0644; + + val_dev_attr->show = gpio_sim_sysfs_val_show; + val_dev_attr->store = gpio_sim_sysfs_val_store; + pull_dev_attr->show = gpio_sim_sysfs_pull_show; + pull_dev_attr->store = gpio_sim_sysfs_pull_store; + + attrs[0] = &val_dev_attr->attr; + attrs[1] = &pull_dev_attr->attr; + + attr_group->attrs = attrs; + chip->attr_groups[i] = attr_group; + } + + ret = sysfs_create_groups(&chip->gc.gpiodev->dev.kobj, + chip->attr_groups); + if (ret) + return ret; + + return devm_add_action_or_reset(dev, gpio_sim_sysfs_remove, chip); +} + +static int gpio_sim_add_bank(struct fwnode_handle *swnode, struct device *dev) +{ + struct gpio_sim_chip *chip; + struct gpio_chip *gc; + const char *label; + u32 num_lines; + int ret; + + ret = fwnode_property_read_u32(swnode, "ngpios", &num_lines); + if (ret) + return ret; + + ret = fwnode_property_read_string(swnode, "gpio-sim,label", &label); + if (ret) { + label = devm_kasprintf(dev, GFP_KERNEL, "%s-%s", + dev_name(dev), fwnode_get_name(swnode)); + if (!label) + return -ENOMEM; + } + + chip = devm_kzalloc(dev, sizeof(*chip), GFP_KERNEL); + if (!chip) + return -ENOMEM; + + chip->direction_map = devm_bitmap_alloc(dev, num_lines, GFP_KERNEL); + if (!chip->direction_map) + return -ENOMEM; + + /* Default to input mode. */ + bitmap_fill(chip->direction_map, num_lines); + + chip->value_map = devm_bitmap_zalloc(dev, num_lines, GFP_KERNEL); + if (!chip->value_map) + return -ENOMEM; + + chip->pull_map = devm_bitmap_zalloc(dev, num_lines, GFP_KERNEL); + if (!chip->pull_map) + return -ENOMEM; + + chip->irq_sim = devm_irq_domain_create_sim(dev, NULL, num_lines); + if (IS_ERR(chip->irq_sim)) + return PTR_ERR(chip->irq_sim); + + mutex_init(&chip->lock); + ret = devm_add_action_or_reset(dev, gpio_sim_mutex_destroy, + &chip->lock); + if (ret) + return ret; + + gc = &chip->gc; + gc->base = -1; + gc->ngpio = num_lines; + gc->label = label; + gc->owner = THIS_MODULE; + gc->parent = dev; + gc->fwnode = swnode; + gc->get = gpio_sim_get; + gc->set = gpio_sim_set; + gc->get_multiple = gpio_sim_get_multiple; + gc->set_multiple = gpio_sim_set_multiple; + gc->direction_output = gpio_sim_direction_output; + gc->direction_input = gpio_sim_direction_input; + gc->get_direction = gpio_sim_get_direction; + gc->set_config = gpio_sim_set_config; + gc->to_irq = gpio_sim_to_irq; + gc->free = gpio_sim_free; + + ret = devm_gpiochip_add_data(dev, gc, chip); + if (ret) + return ret; + + /* Used by sysfs and configfs callbacks. */ + dev_set_drvdata(&gc->gpiodev->dev, chip); + + return gpio_sim_setup_sysfs(chip); +} + +static int gpio_sim_probe(struct platform_device *pdev) +{ + struct device *dev = &pdev->dev; + struct fwnode_handle *swnode; + int ret; + + device_for_each_child_node(dev, swnode) { + ret = gpio_sim_add_bank(swnode, dev); + if (ret) { + fwnode_handle_put(swnode); + return ret; + } + } + + return 0; +} + +static const struct of_device_id gpio_sim_of_match[] = { + { .compatible = "gpio-simulator" }, + { } +}; +MODULE_DEVICE_TABLE(of, gpio_sim_of_match); + +static struct platform_driver gpio_sim_driver = { + .driver = { + .name = "gpio-sim", + .of_match_table = gpio_sim_of_match, + }, + .probe = gpio_sim_probe, +}; + +struct gpio_sim_device { + struct config_group group; + + /* + * If pdev is NULL, the device is 'pending' (waiting for configuration). + * Once the pointer is assigned, the device has been created and the + * item is 'live'. + */ + struct platform_device *pdev; + int id; + + /* + * Each configfs filesystem operation is protected with the subsystem + * mutex. Each separate attribute is protected with the buffer mutex. + * This structure however can be modified by callbacks of different + * attributes so we need another lock. + * + * We use this lock fo protecting all data structures owned by this + * object too. + */ + struct mutex lock; + + /* + * This is used to synchronously wait for the driver's probe to complete + * and notify the user-space about any errors. + */ + struct notifier_block bus_notifier; + struct completion probe_completion; + bool driver_bound; + + struct gpiod_hog *hogs; + + struct list_head bank_list; +}; + +/* This is called with dev->lock already taken. */ +static int gpio_sim_bus_notifier_call(struct notifier_block *nb, + unsigned long action, void *data) +{ + struct gpio_sim_device *simdev = container_of(nb, + struct gpio_sim_device, + bus_notifier); + struct device *dev = data; + char devname[32]; + + snprintf(devname, sizeof(devname), "gpio-sim.%u", simdev->id); + + if (strcmp(dev_name(dev), devname) == 0) { + if (action == BUS_NOTIFY_BOUND_DRIVER) + simdev->driver_bound = true; + else if (action == BUS_NOTIFY_DRIVER_NOT_BOUND) + simdev->driver_bound = false; + else + return NOTIFY_DONE; + + complete(&simdev->probe_completion); + return NOTIFY_OK; + } + + return NOTIFY_DONE; +} + +static struct gpio_sim_device *to_gpio_sim_device(struct config_item *item) +{ + struct config_group *group = to_config_group(item); + + return container_of(group, struct gpio_sim_device, group); +} + +struct gpio_sim_bank { + struct config_group group; + + /* + * We could have used the ci_parent field of the config_item but + * configfs is stupid and calls the item's release callback after + * already having cleared the parent pointer even though the parent + * is guaranteed to survive the child... + * + * So we need to store the pointer to the parent struct here. We can + * dereference it anywhere we need with no checks and no locking as + * it's guaranteed to survive the childred and protected by configfs + * locks. + * + * Same for other structures. + */ + struct gpio_sim_device *parent; + struct list_head siblings; + + char *label; + unsigned int num_lines; + + struct list_head line_list; + + struct fwnode_handle *swnode; +}; + +static struct gpio_sim_bank *to_gpio_sim_bank(struct config_item *item) +{ + struct config_group *group = to_config_group(item); + + return container_of(group, struct gpio_sim_bank, group); +} + +static struct gpio_sim_device * +gpio_sim_bank_get_device(struct gpio_sim_bank *bank) +{ + return bank->parent; +} + +struct gpio_sim_hog; + +struct gpio_sim_line { + struct config_group group; + + struct gpio_sim_bank *parent; + struct list_head siblings; + + unsigned int offset; + char *name; + + /* There can only be one hog per line. */ + struct gpio_sim_hog *hog; +}; + +static struct gpio_sim_line *to_gpio_sim_line(struct config_item *item) +{ + struct config_group *group = to_config_group(item); + + return container_of(group, struct gpio_sim_line, group); +} + +static struct gpio_sim_device * +gpio_sim_line_get_device(struct gpio_sim_line *line) +{ + struct gpio_sim_bank *bank = line->parent; + + return gpio_sim_bank_get_device(bank); +} + +struct gpio_sim_hog { + struct config_item item; + struct gpio_sim_line *parent; + + char *name; + int dir; +}; + +static struct gpio_sim_hog *to_gpio_sim_hog(struct config_item *item) +{ + return container_of(item, struct gpio_sim_hog, item); +} + +static struct gpio_sim_device *gpio_sim_hog_get_device(struct gpio_sim_hog *hog) +{ + struct gpio_sim_line *line = hog->parent; + + return gpio_sim_line_get_device(line); +} + +static bool gpio_sim_device_is_live_unlocked(struct gpio_sim_device *dev) +{ + return !!dev->pdev; +} + +static char *gpio_sim_strdup_trimmed(const char *str, size_t count) +{ + char *dup, *trimmed; + + dup = kstrndup(str, count, GFP_KERNEL); + if (!dup) + return NULL; + + trimmed = strstrip(dup); + memmove(dup, trimmed, strlen(trimmed) + 1); + + return dup; +} + +static ssize_t gpio_sim_device_config_dev_name_show(struct config_item *item, + char *page) +{ + struct gpio_sim_device *dev = to_gpio_sim_device(item); + struct platform_device *pdev; + int ret; + + mutex_lock(&dev->lock); + pdev = dev->pdev; + if (pdev) + ret = sprintf(page, "%s\n", dev_name(&pdev->dev)); + else + ret = sprintf(page, "gpio-sim.%d\n", dev->id); + mutex_unlock(&dev->lock); + + return ret; +} + +CONFIGFS_ATTR_RO(gpio_sim_device_config_, dev_name); + +static ssize_t +gpio_sim_device_config_live_show(struct config_item *item, char *page) +{ + struct gpio_sim_device *dev = to_gpio_sim_device(item); + bool live; + + mutex_lock(&dev->lock); + live = gpio_sim_device_is_live_unlocked(dev); + mutex_unlock(&dev->lock); + + return sprintf(page, "%c\n", live ? '1' : '0'); +} + +static char **gpio_sim_make_line_names(struct gpio_sim_bank *bank, + unsigned int *line_names_size) +{ + unsigned int max_offset = 0; + bool has_line_names = false; + struct gpio_sim_line *line; + char **line_names; + + list_for_each_entry(line, &bank->line_list, siblings) { + if (line->name) { + if (line->offset > max_offset) + max_offset = line->offset; + + /* + * max_offset can stay at 0 so it's not an indicator + * of whether line names were configured at all. + */ + has_line_names = true; + } + } + + if (!has_line_names) + /* + * This is not an error - NULL means, there are no line + * names configured. + */ + return NULL; + + *line_names_size = max_offset + 1; + + line_names = kcalloc(*line_names_size, sizeof(*line_names), GFP_KERNEL); + if (!line_names) + return ERR_PTR(-ENOMEM); + + list_for_each_entry(line, &bank->line_list, siblings) + line_names[line->offset] = line->name; + + return line_names; +} + +static void gpio_sim_remove_hogs(struct gpio_sim_device *dev) +{ + struct gpiod_hog *hog; + + if (!dev->hogs) + return; + + gpiod_remove_hogs(dev->hogs); + + for (hog = dev->hogs; !hog->chip_label; hog++) { + kfree(hog->chip_label); + kfree(hog->line_name); + } + + kfree(dev->hogs); + dev->hogs = NULL; +} + +static int gpio_sim_add_hogs(struct gpio_sim_device *dev) +{ + unsigned int num_hogs = 0, idx = 0; + struct gpio_sim_bank *bank; + struct gpio_sim_line *line; + struct gpiod_hog *hog; + + list_for_each_entry(bank, &dev->bank_list, siblings) { + list_for_each_entry(line, &bank->line_list, siblings) { + if (line->hog) + num_hogs++; + } + } + + if (!num_hogs) + return 0; + + /* Allocate one more for the sentinel. */ + dev->hogs = kcalloc(num_hogs + 1, sizeof(*dev->hogs), GFP_KERNEL); + if (!dev->hogs) + return -ENOMEM; + + list_for_each_entry(bank, &dev->bank_list, siblings) { + list_for_each_entry(line, &bank->line_list, siblings) { + if (!line->hog) + continue; + + hog = &dev->hogs[idx++]; + + /* + * We need to make this string manually because at this + * point the device doesn't exist yet and so dev_name() + * is not available. + */ + hog->chip_label = kasprintf(GFP_KERNEL, + "gpio-sim.%u-%s", dev->id, + fwnode_get_name(bank->swnode)); + if (!hog->chip_label) { + gpio_sim_remove_hogs(dev); + return -ENOMEM; + } + + /* + * We need to duplicate this because the hog config + * item can be removed at any time (and we can't block + * it) and gpiolib doesn't make a deep copy of the hog + * data. + */ + if (line->hog->name) { + hog->line_name = kstrdup(line->hog->name, + GFP_KERNEL); + if (!hog->line_name) { + gpio_sim_remove_hogs(dev); + return -ENOMEM; + } + } + + hog->chip_hwnum = line->offset; + hog->dflags = line->hog->dir; + } + } + + gpiod_add_hogs(dev->hogs); + + return 0; +} + +static struct fwnode_handle * +gpio_sim_make_bank_swnode(struct gpio_sim_bank *bank, + struct fwnode_handle *parent) +{ + struct property_entry properties[GPIO_SIM_PROP_MAX]; + unsigned int prop_idx = 0, line_names_size = 0; + struct fwnode_handle *swnode; + char **line_names; + + memset(properties, 0, sizeof(properties)); + + properties[prop_idx++] = PROPERTY_ENTRY_U32("ngpios", bank->num_lines); + + if (bank->label && (strlen(bank->label) > 0)) + properties[prop_idx++] = PROPERTY_ENTRY_STRING("gpio-sim,label", + bank->label); + + line_names = gpio_sim_make_line_names(bank, &line_names_size); + if (IS_ERR(line_names)) + return ERR_CAST(line_names); + + if (line_names) + properties[prop_idx++] = PROPERTY_ENTRY_STRING_ARRAY_LEN( + "gpio-line-names", + line_names, line_names_size); + + swnode = fwnode_create_software_node(properties, parent); + kfree(line_names); + return swnode; +} + +static void gpio_sim_remove_swnode_recursive(struct fwnode_handle *swnode) +{ + struct fwnode_handle *child; + + fwnode_for_each_child_node(swnode, child) + fwnode_remove_software_node(child); + + fwnode_remove_software_node(swnode); +} + +static bool gpio_sim_bank_labels_non_unique(struct gpio_sim_device *dev) +{ + struct gpio_sim_bank *this, *pos; + + list_for_each_entry(this, &dev->bank_list, siblings) { + list_for_each_entry(pos, &dev->bank_list, siblings) { + if (this == pos || (!this->label || !pos->label)) + continue; + + if (strcmp(this->label, pos->label) == 0) + return true; + } + } + + return false; +} + +static int gpio_sim_device_activate_unlocked(struct gpio_sim_device *dev) +{ + struct platform_device_info pdevinfo; + struct fwnode_handle *swnode; + struct platform_device *pdev; + struct gpio_sim_bank *bank; + int ret; + + if (list_empty(&dev->bank_list)) + return -ENODATA; + + /* + * Non-unique GPIO device labels are a corner-case we don't support + * as it would interfere with machine hogging mechanism and has little + * use in real life. + */ + if (gpio_sim_bank_labels_non_unique(dev)) + return -EINVAL; + + memset(&pdevinfo, 0, sizeof(pdevinfo)); + + swnode = fwnode_create_software_node(NULL, NULL); + if (IS_ERR(swnode)) + return PTR_ERR(swnode); + + list_for_each_entry(bank, &dev->bank_list, siblings) { + bank->swnode = gpio_sim_make_bank_swnode(bank, swnode); + if (IS_ERR(bank->swnode)) { + ret = PTR_ERR(bank->swnode); + gpio_sim_remove_swnode_recursive(swnode); + return ret; + } + } + + ret = gpio_sim_add_hogs(dev); + if (ret) { + gpio_sim_remove_swnode_recursive(swnode); + return ret; + } + + pdevinfo.name = "gpio-sim"; + pdevinfo.fwnode = swnode; + pdevinfo.id = dev->id; + + reinit_completion(&dev->probe_completion); + dev->driver_bound = false; + bus_register_notifier(&platform_bus_type, &dev->bus_notifier); + + pdev = platform_device_register_full(&pdevinfo); + if (IS_ERR(pdev)) { + bus_unregister_notifier(&platform_bus_type, &dev->bus_notifier); + gpio_sim_remove_hogs(dev); + gpio_sim_remove_swnode_recursive(swnode); + return PTR_ERR(pdev); + } + + wait_for_completion(&dev->probe_completion); + bus_unregister_notifier(&platform_bus_type, &dev->bus_notifier); + + if (!dev->driver_bound) { + /* Probe failed, check kernel log. */ + platform_device_unregister(pdev); + gpio_sim_remove_hogs(dev); + gpio_sim_remove_swnode_recursive(swnode); + return -ENXIO; + } + + dev->pdev = pdev; + + return 0; +} + +static void gpio_sim_device_deactivate_unlocked(struct gpio_sim_device *dev) +{ + struct fwnode_handle *swnode; + + swnode = dev_fwnode(&dev->pdev->dev); + platform_device_unregister(dev->pdev); + gpio_sim_remove_swnode_recursive(swnode); + dev->pdev = NULL; + gpio_sim_remove_hogs(dev); +} + +static ssize_t +gpio_sim_device_config_live_store(struct config_item *item, + const char *page, size_t count) +{ + struct gpio_sim_device *dev = to_gpio_sim_device(item); + bool live; + int ret; + + ret = kstrtobool(page, &live); + if (ret) + return ret; + + mutex_lock(&dev->lock); + + if ((!live && !gpio_sim_device_is_live_unlocked(dev)) || + (live && gpio_sim_device_is_live_unlocked(dev))) + ret = -EPERM; + else if (live) + ret = gpio_sim_device_activate_unlocked(dev); + else + gpio_sim_device_deactivate_unlocked(dev); + + mutex_unlock(&dev->lock); + + return ret ?: count; +} + +CONFIGFS_ATTR(gpio_sim_device_config_, live); + +static struct configfs_attribute *gpio_sim_device_config_attrs[] = { + &gpio_sim_device_config_attr_dev_name, + &gpio_sim_device_config_attr_live, + NULL +}; + +struct gpio_sim_chip_name_ctx { + struct gpio_sim_device *dev; + char *page; +}; + +static int gpio_sim_emit_chip_name(struct device *dev, void *data) +{ + struct gpio_sim_chip_name_ctx *ctx = data; + struct fwnode_handle *swnode; + struct gpio_sim_bank *bank; + + /* This would be the sysfs device exported in /sys/class/gpio. */ + if (dev->class) + return 0; + + swnode = dev_fwnode(dev); + + list_for_each_entry(bank, &ctx->dev->bank_list, siblings) { + if (bank->swnode == swnode) + return sprintf(ctx->page, "%s\n", dev_name(dev)); + } + + return -ENODATA; +} + +static ssize_t gpio_sim_bank_config_chip_name_show(struct config_item *item, + char *page) +{ + struct gpio_sim_bank *bank = to_gpio_sim_bank(item); + struct gpio_sim_device *dev = gpio_sim_bank_get_device(bank); + struct gpio_sim_chip_name_ctx ctx = { dev, page }; + int ret; + + mutex_lock(&dev->lock); + if (gpio_sim_device_is_live_unlocked(dev)) + ret = device_for_each_child(&dev->pdev->dev, &ctx, + gpio_sim_emit_chip_name); + else + ret = sprintf(page, "none\n"); + mutex_unlock(&dev->lock); + + return ret; +} + +CONFIGFS_ATTR_RO(gpio_sim_bank_config_, chip_name); + +static ssize_t +gpio_sim_bank_config_label_show(struct config_item *item, char *page) +{ + struct gpio_sim_bank *bank = to_gpio_sim_bank(item); + struct gpio_sim_device *dev = gpio_sim_bank_get_device(bank); + int ret; + + mutex_lock(&dev->lock); + ret = sprintf(page, "%s\n", bank->label ?: ""); + mutex_unlock(&dev->lock); + + return ret; +} + +static ssize_t gpio_sim_bank_config_label_store(struct config_item *item, + const char *page, size_t count) +{ + struct gpio_sim_bank *bank = to_gpio_sim_bank(item); + struct gpio_sim_device *dev = gpio_sim_bank_get_device(bank); + char *trimmed; + + mutex_lock(&dev->lock); + + if (gpio_sim_device_is_live_unlocked(dev)) { + mutex_unlock(&dev->lock); + return -EBUSY; + } + + trimmed = gpio_sim_strdup_trimmed(page, count); + if (!trimmed) { + mutex_unlock(&dev->lock); + return -ENOMEM; + } + + kfree(bank->label); + bank->label = trimmed; + + mutex_unlock(&dev->lock); + return count; +} + +CONFIGFS_ATTR(gpio_sim_bank_config_, label); + +static ssize_t +gpio_sim_bank_config_num_lines_show(struct config_item *item, char *page) +{ + struct gpio_sim_bank *bank = to_gpio_sim_bank(item); + struct gpio_sim_device *dev = gpio_sim_bank_get_device(bank); + int ret; + + mutex_lock(&dev->lock); + ret = sprintf(page, "%u\n", bank->num_lines); + mutex_unlock(&dev->lock); + + return ret; +} + +static ssize_t +gpio_sim_bank_config_num_lines_store(struct config_item *item, + const char *page, size_t count) +{ + struct gpio_sim_bank *bank = to_gpio_sim_bank(item); + struct gpio_sim_device *dev = gpio_sim_bank_get_device(bank); + unsigned int num_lines; + int ret; + + ret = kstrtouint(page, 0, &num_lines); + if (ret) + return ret; + + if (num_lines == 0) + return -EINVAL; + + mutex_lock(&dev->lock); + + if (gpio_sim_device_is_live_unlocked(dev)) { + mutex_unlock(&dev->lock); + return -EBUSY; + } + + bank->num_lines = num_lines; + + mutex_unlock(&dev->lock); + return count; +} + +CONFIGFS_ATTR(gpio_sim_bank_config_, num_lines); + +static struct configfs_attribute *gpio_sim_bank_config_attrs[] = { + &gpio_sim_bank_config_attr_chip_name, + &gpio_sim_bank_config_attr_label, + &gpio_sim_bank_config_attr_num_lines, + NULL +}; + +static ssize_t +gpio_sim_line_config_name_show(struct config_item *item, char *page) +{ + struct gpio_sim_line *line = to_gpio_sim_line(item); + struct gpio_sim_device *dev = gpio_sim_line_get_device(line); + int ret; + + mutex_lock(&dev->lock); + ret = sprintf(page, "%s\n", line->name ?: ""); + mutex_unlock(&dev->lock); + + return ret; +} + +static ssize_t gpio_sim_line_config_name_store(struct config_item *item, + const char *page, size_t count) +{ + struct gpio_sim_line *line = to_gpio_sim_line(item); + struct gpio_sim_device *dev = gpio_sim_line_get_device(line); + char *trimmed; + + mutex_lock(&dev->lock); + + if (gpio_sim_device_is_live_unlocked(dev)) { + mutex_unlock(&dev->lock); + return -EBUSY; + } + + trimmed = gpio_sim_strdup_trimmed(page, count); + if (!trimmed) { + mutex_unlock(&dev->lock); + return -ENOMEM; + } + + kfree(line->name); + line->name = trimmed; + + mutex_unlock(&dev->lock); + + return count; +} + +CONFIGFS_ATTR(gpio_sim_line_config_, name); + +static struct configfs_attribute *gpio_sim_line_config_attrs[] = { + &gpio_sim_line_config_attr_name, + NULL +}; + +static ssize_t gpio_sim_hog_config_name_show(struct config_item *item, + char *page) +{ + struct gpio_sim_hog *hog = to_gpio_sim_hog(item); + struct gpio_sim_device *dev = gpio_sim_hog_get_device(hog); + int ret; + + mutex_lock(&dev->lock); + ret = sprintf(page, "%s\n", hog->name ?: ""); + mutex_unlock(&dev->lock); + + return ret; +} + +static ssize_t gpio_sim_hog_config_name_store(struct config_item *item, + const char *page, size_t count) +{ + struct gpio_sim_hog *hog = to_gpio_sim_hog(item); + struct gpio_sim_device *dev = gpio_sim_hog_get_device(hog); + char *trimmed; + + mutex_lock(&dev->lock); + + if (gpio_sim_device_is_live_unlocked(dev)) { + mutex_unlock(&dev->lock); + return -EBUSY; + } + + trimmed = gpio_sim_strdup_trimmed(page, count); + if (!trimmed) { + mutex_unlock(&dev->lock); + return -ENOMEM; + } + + kfree(hog->name); + hog->name = trimmed; + + mutex_unlock(&dev->lock); + + return count; +} + +CONFIGFS_ATTR(gpio_sim_hog_config_, name); + +static ssize_t gpio_sim_hog_config_direction_show(struct config_item *item, + char *page) +{ + struct gpio_sim_hog *hog = to_gpio_sim_hog(item); + struct gpio_sim_device *dev = gpio_sim_hog_get_device(hog); + char *repr; + int dir; + + mutex_lock(&dev->lock); + dir = hog->dir; + mutex_unlock(&dev->lock); + + switch (dir) { + case GPIOD_IN: + repr = "input"; + break; + case GPIOD_OUT_HIGH: + repr = "output-high"; + break; + case GPIOD_OUT_LOW: + repr = "output-low"; + break; + default: + /* This would be a programmer bug. */ + WARN(1, "Unexpected hog direction value: %d", dir); + return -EINVAL; + } + + return sprintf(page, "%s\n", repr); +} + +static ssize_t +gpio_sim_hog_config_direction_store(struct config_item *item, + const char *page, size_t count) +{ + struct gpio_sim_hog *hog = to_gpio_sim_hog(item); + struct gpio_sim_device *dev = gpio_sim_hog_get_device(hog); + char *trimmed; + int dir; + + mutex_lock(&dev->lock); + + if (gpio_sim_device_is_live_unlocked(dev)) { + mutex_unlock(&dev->lock); + return -EBUSY; + } + + trimmed = gpio_sim_strdup_trimmed(page, count); + if (!trimmed) { + mutex_unlock(&dev->lock); + return -ENOMEM; + } + + if (strcmp(trimmed, "input") == 0) + dir = GPIOD_IN; + else if (strcmp(trimmed, "output-high") == 0) + dir = GPIOD_OUT_HIGH; + else if (strcmp(trimmed, "output-low") == 0) + dir = GPIOD_OUT_LOW; + else + dir = -EINVAL; + + kfree(trimmed); + + if (dir < 0) { + mutex_unlock(&dev->lock); + return dir; + } + + hog->dir = dir; + + mutex_unlock(&dev->lock); + + return count; +} + +CONFIGFS_ATTR(gpio_sim_hog_config_, direction); + +static struct configfs_attribute *gpio_sim_hog_config_attrs[] = { + &gpio_sim_hog_config_attr_name, + &gpio_sim_hog_config_attr_direction, + NULL +}; + +static void gpio_sim_hog_config_item_release(struct config_item *item) +{ + struct gpio_sim_hog *hog = to_gpio_sim_hog(item); + struct gpio_sim_line *line = hog->parent; + struct gpio_sim_device *dev = gpio_sim_hog_get_device(hog); + + mutex_lock(&dev->lock); + line->hog = NULL; + mutex_unlock(&dev->lock); + + kfree(hog->name); + kfree(hog); +} + +struct configfs_item_operations gpio_sim_hog_config_item_ops = { + .release = gpio_sim_hog_config_item_release, +}; + +static const struct config_item_type gpio_sim_hog_config_type = { + .ct_item_ops = &gpio_sim_hog_config_item_ops, + .ct_attrs = gpio_sim_hog_config_attrs, + .ct_owner = THIS_MODULE, +}; + +static struct config_item * +gpio_sim_line_config_make_hog_item(struct config_group *group, const char *name) +{ + struct gpio_sim_line *line = to_gpio_sim_line(&group->cg_item); + struct gpio_sim_device *dev = gpio_sim_line_get_device(line); + struct gpio_sim_hog *hog; + + if (strcmp(name, "hog") != 0) + return ERR_PTR(-EINVAL); + + mutex_lock(&dev->lock); + + hog = kzalloc(sizeof(*hog), GFP_KERNEL); + if (!hog) { + mutex_unlock(&dev->lock); + return ERR_PTR(-ENOMEM); + } + + config_item_init_type_name(&hog->item, name, + &gpio_sim_hog_config_type); + + hog->dir = GPIOD_IN; + hog->name = NULL; + hog->parent = line; + line->hog = hog; + + mutex_unlock(&dev->lock); + + return &hog->item; +} + +static void gpio_sim_line_config_group_release(struct config_item *item) +{ + struct gpio_sim_line *line = to_gpio_sim_line(item); + struct gpio_sim_device *dev = gpio_sim_line_get_device(line); + + mutex_lock(&dev->lock); + list_del(&line->siblings); + mutex_unlock(&dev->lock); + + kfree(line->name); + kfree(line); +} + +static struct configfs_item_operations gpio_sim_line_config_item_ops = { + .release = gpio_sim_line_config_group_release, +}; + +static struct configfs_group_operations gpio_sim_line_config_group_ops = { + .make_item = gpio_sim_line_config_make_hog_item, +}; + +static const struct config_item_type gpio_sim_line_config_type = { + .ct_item_ops = &gpio_sim_line_config_item_ops, + .ct_group_ops = &gpio_sim_line_config_group_ops, + .ct_attrs = gpio_sim_line_config_attrs, + .ct_owner = THIS_MODULE, +}; + +static struct config_group * +gpio_sim_bank_config_make_line_group(struct config_group *group, + const char *name) +{ + struct gpio_sim_bank *bank = to_gpio_sim_bank(&group->cg_item); + struct gpio_sim_device *dev = gpio_sim_bank_get_device(bank); + struct gpio_sim_line *line; + unsigned int offset; + int ret, nchar; + + ret = sscanf(name, "line%u%n", &offset, &nchar); + if (ret != 1 || nchar != strlen(name)) + return ERR_PTR(-EINVAL); + + mutex_lock(&dev->lock); + + if (gpio_sim_device_is_live_unlocked(dev)) { + mutex_unlock(&dev->lock); + return ERR_PTR(-EBUSY); + } + + line = kzalloc(sizeof(*line), GFP_KERNEL); + if (!line) { + mutex_unlock(&dev->lock); + return ERR_PTR(-ENOMEM); + } + + config_group_init_type_name(&line->group, name, + &gpio_sim_line_config_type); + + line->parent = bank; + line->offset = offset; + list_add_tail(&line->siblings, &bank->line_list); + + mutex_unlock(&dev->lock); + + return &line->group; +} + +static void gpio_sim_bank_config_group_release(struct config_item *item) +{ + struct gpio_sim_bank *bank = to_gpio_sim_bank(item); + struct gpio_sim_device *dev = gpio_sim_bank_get_device(bank); + + mutex_lock(&dev->lock); + list_del(&bank->siblings); + mutex_unlock(&dev->lock); + + kfree(bank->label); + kfree(bank); +} + +static struct configfs_item_operations gpio_sim_bank_config_item_ops = { + .release = gpio_sim_bank_config_group_release, +}; + +static struct configfs_group_operations gpio_sim_bank_config_group_ops = { + .make_group = gpio_sim_bank_config_make_line_group, +}; + +static const struct config_item_type gpio_sim_bank_config_group_type = { + .ct_item_ops = &gpio_sim_bank_config_item_ops, + .ct_group_ops = &gpio_sim_bank_config_group_ops, + .ct_attrs = gpio_sim_bank_config_attrs, + .ct_owner = THIS_MODULE, +}; + +static struct config_group * +gpio_sim_device_config_make_bank_group(struct config_group *group, + const char *name) +{ + struct gpio_sim_device *dev = to_gpio_sim_device(&group->cg_item); + struct gpio_sim_bank *bank; + + mutex_lock(&dev->lock); + + if (gpio_sim_device_is_live_unlocked(dev)) { + mutex_unlock(&dev->lock); + return ERR_PTR(-EBUSY); + } + + bank = kzalloc(sizeof(*bank), GFP_KERNEL); + if (!bank) { + mutex_unlock(&dev->lock); + return ERR_PTR(-ENOMEM); + } + + config_group_init_type_name(&bank->group, name, + &gpio_sim_bank_config_group_type); + bank->num_lines = 1; + bank->parent = dev; + INIT_LIST_HEAD(&bank->line_list); + list_add_tail(&bank->siblings, &dev->bank_list); + + mutex_unlock(&dev->lock); + + return &bank->group; +} + +static void gpio_sim_device_config_group_release(struct config_item *item) +{ + struct gpio_sim_device *dev = to_gpio_sim_device(item); + + mutex_lock(&dev->lock); + if (gpio_sim_device_is_live_unlocked(dev)) + gpio_sim_device_deactivate_unlocked(dev); + mutex_unlock(&dev->lock); + + mutex_destroy(&dev->lock); + ida_free(&gpio_sim_ida, dev->id); + kfree(dev); +} + +static struct configfs_item_operations gpio_sim_device_config_item_ops = { + .release = gpio_sim_device_config_group_release, +}; + +static struct configfs_group_operations gpio_sim_device_config_group_ops = { + .make_group = gpio_sim_device_config_make_bank_group, +}; + +static const struct config_item_type gpio_sim_device_config_group_type = { + .ct_item_ops = &gpio_sim_device_config_item_ops, + .ct_group_ops = &gpio_sim_device_config_group_ops, + .ct_attrs = gpio_sim_device_config_attrs, + .ct_owner = THIS_MODULE, +}; + +static struct config_group * +gpio_sim_config_make_device_group(struct config_group *group, const char *name) +{ + struct gpio_sim_device *dev; + int id; + + dev = kzalloc(sizeof(*dev), GFP_KERNEL); + if (!dev) + return ERR_PTR(-ENOMEM); + + id = ida_alloc(&gpio_sim_ida, GFP_KERNEL); + if (id < 0) { + kfree(dev); + return ERR_PTR(id); + } + + config_group_init_type_name(&dev->group, name, + &gpio_sim_device_config_group_type); + dev->id = id; + mutex_init(&dev->lock); + INIT_LIST_HEAD(&dev->bank_list); + + dev->bus_notifier.notifier_call = gpio_sim_bus_notifier_call; + init_completion(&dev->probe_completion); + + return &dev->group; +} + +static struct configfs_group_operations gpio_sim_config_group_ops = { + .make_group = gpio_sim_config_make_device_group, +}; + +static const struct config_item_type gpio_sim_config_type = { + .ct_group_ops = &gpio_sim_config_group_ops, + .ct_owner = THIS_MODULE, +}; + +static struct configfs_subsystem gpio_sim_config_subsys = { + .su_group = { + .cg_item = { + .ci_namebuf = "gpio-sim", + .ci_type = &gpio_sim_config_type, + }, + }, +}; + +static int __init gpio_sim_init(void) +{ + int ret; + + ret = platform_driver_register(&gpio_sim_driver); + if (ret) { + pr_err("Error %d while registering the platform driver\n", ret); + return ret; + } + + config_group_init(&gpio_sim_config_subsys.su_group); + mutex_init(&gpio_sim_config_subsys.su_mutex); + ret = configfs_register_subsystem(&gpio_sim_config_subsys); + if (ret) { + pr_err("Error %d while registering the configfs subsystem %s\n", + ret, gpio_sim_config_subsys.su_group.cg_item.ci_namebuf); + mutex_destroy(&gpio_sim_config_subsys.su_mutex); + platform_driver_unregister(&gpio_sim_driver); + return ret; + } + + return 0; +} +module_init(gpio_sim_init); + +static void __exit gpio_sim_exit(void) +{ + configfs_unregister_subsystem(&gpio_sim_config_subsys); + mutex_destroy(&gpio_sim_config_subsys.su_mutex); + platform_driver_unregister(&gpio_sim_driver); +} +module_exit(gpio_sim_exit); + +MODULE_AUTHOR("Bartosz Golaszewski <brgl@bgdev.pl"); +MODULE_DESCRIPTION("GPIO Simulator Module"); +MODULE_LICENSE("GPL"); |