// SPDX-License-Identifier: GPL-2.0-only
/*
 * LED Class Core
 *
 * Copyright (C) 2005 John Lenz <lenz@cs.wisc.edu>
 * Copyright (C) 2005-2007 Richard Purdie <rpurdie@openedhand.com>
 */

#include <linux/ctype.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/leds.h>
#include <linux/list.h>
#include <linux/module.h>
#include <linux/property.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/timer.h>
#include <uapi/linux/uleds.h>
#include <linux/of.h>
#include "leds.h"

static DEFINE_MUTEX(leds_lookup_lock);
static LIST_HEAD(leds_lookup_list);

static struct workqueue_struct *leds_wq;

static bool led_trigger_is_hw_controlled(struct led_classdev *led_cdev)
{
#ifdef CONFIG_LEDS_TRIGGERS
        guard(rwsem_read)(&led_cdev->trigger_lock);
        return led_cdev->trigger && led_cdev->trigger->trigger_type;
#else
        return false;
#endif
}

static ssize_t brightness_show(struct device *dev,
                struct device_attribute *attr, char *buf)
{
        struct led_classdev *led_cdev = dev_get_drvdata(dev);
        unsigned int brightness;

        if (led_trigger_is_hw_controlled(led_cdev))
                return -ENODATA;

        mutex_lock(&led_cdev->led_access);
        led_update_brightness(led_cdev);
        brightness = led_cdev->brightness;
        mutex_unlock(&led_cdev->led_access);

        return sysfs_emit(buf, "%u\n", brightness);
}

static ssize_t brightness_store(struct device *dev,
                struct device_attribute *attr, const char *buf, size_t size)
{
        struct led_classdev *led_cdev = dev_get_drvdata(dev);
        unsigned long state;
        ssize_t ret;

        mutex_lock(&led_cdev->led_access);

        if (led_sysfs_is_disabled(led_cdev)) {
                ret = -EBUSY;
                goto unlock;
        }

        ret = kstrtoul(buf, 10, &state);
        if (ret)
                goto unlock;

        if (state == LED_OFF)
                led_trigger_remove(led_cdev);
        led_set_brightness(led_cdev, state);

        ret = size;
unlock:
        mutex_unlock(&led_cdev->led_access);
        return ret;
}
static DEVICE_ATTR_RW(brightness);

static ssize_t max_brightness_show(struct device *dev,
                struct device_attribute *attr, char *buf)
{
        struct led_classdev *led_cdev = dev_get_drvdata(dev);
        unsigned int max_brightness;

        mutex_lock(&led_cdev->led_access);
        max_brightness = led_cdev->max_brightness;
        mutex_unlock(&led_cdev->led_access);

        return sysfs_emit(buf, "%u\n", max_brightness);
}
static DEVICE_ATTR_RO(max_brightness);

#ifdef CONFIG_LEDS_TRIGGERS
static const BIN_ATTR(trigger, 0644, led_trigger_read, led_trigger_write, 0);
static const struct bin_attribute *const led_trigger_bin_attrs[] = {
        &bin_attr_trigger,
        NULL,
};
static const struct attribute_group led_trigger_group = {
        .bin_attrs = led_trigger_bin_attrs,
};
#endif

static struct attribute *led_class_attrs[] = {
        &dev_attr_brightness.attr,
        &dev_attr_max_brightness.attr,
        NULL,
};

static const struct attribute_group led_group = {
        .attrs = led_class_attrs,
};

static const struct attribute_group *led_groups[] = {
        &led_group,
#ifdef CONFIG_LEDS_TRIGGERS
        &led_trigger_group,
#endif
        NULL,
};

#ifdef CONFIG_LEDS_BRIGHTNESS_HW_CHANGED
static ssize_t brightness_hw_changed_show(struct device *dev,
                struct device_attribute *attr, char *buf)
{
        struct led_classdev *led_cdev = dev_get_drvdata(dev);

        if (led_cdev->brightness_hw_changed == -1)
                return -ENODATA;

        return sysfs_emit(buf, "%u\n", led_cdev->brightness_hw_changed);
}

static DEVICE_ATTR_RO(brightness_hw_changed);

static int led_add_brightness_hw_changed(struct led_classdev *led_cdev)
{
        struct device *dev = led_cdev->dev;
        int ret;

        ret = device_create_file(dev, &dev_attr_brightness_hw_changed);
        if (ret) {
                dev_err(dev, "Error creating brightness_hw_changed\n");
                return ret;
        }

        led_cdev->brightness_hw_changed_kn =
                sysfs_get_dirent(dev->kobj.sd, "brightness_hw_changed");
        if (!led_cdev->brightness_hw_changed_kn) {
                dev_err(dev, "Error getting brightness_hw_changed kn\n");
                device_remove_file(dev, &dev_attr_brightness_hw_changed);
                return -ENXIO;
        }

        return 0;
}

static void led_remove_brightness_hw_changed(struct led_classdev *led_cdev)
{
        sysfs_put(led_cdev->brightness_hw_changed_kn);
        device_remove_file(led_cdev->dev, &dev_attr_brightness_hw_changed);
}

void led_classdev_notify_brightness_hw_changed(struct led_classdev *led_cdev, unsigned int brightness)
{
        if (WARN_ON(!led_cdev->brightness_hw_changed_kn))
                return;

        led_cdev->brightness_hw_changed = brightness;
        sysfs_notify_dirent(led_cdev->brightness_hw_changed_kn);
}
EXPORT_SYMBOL_GPL(led_classdev_notify_brightness_hw_changed);
#else
static int led_add_brightness_hw_changed(struct led_classdev *led_cdev)
{
        return 0;
}
static void led_remove_brightness_hw_changed(struct led_classdev *led_cdev)
{
}
#endif

/**
 * led_classdev_suspend - suspend an led_classdev.
 * @led_cdev: the led_classdev to suspend.
 */
void led_classdev_suspend(struct led_classdev *led_cdev)
{
        led_cdev->flags |= LED_SUSPENDED;
        led_set_brightness_nopm(led_cdev, 0);
        flush_work(&led_cdev->set_brightness_work);
}
EXPORT_SYMBOL_GPL(led_classdev_suspend);

/**
 * led_classdev_resume - resume an led_classdev.
 * @led_cdev: the led_classdev to resume.
 */
void led_classdev_resume(struct led_classdev *led_cdev)
{
        led_set_brightness_nopm(led_cdev, led_cdev->brightness);

        if (led_cdev->flash_resume)
                led_cdev->flash_resume(led_cdev);

        led_cdev->flags &= ~LED_SUSPENDED;
}
EXPORT_SYMBOL_GPL(led_classdev_resume);

#ifdef CONFIG_PM_SLEEP
static int led_suspend(struct device *dev)
{
        struct led_classdev *led_cdev = dev_get_drvdata(dev);

        if (led_cdev->flags & LED_CORE_SUSPENDRESUME)
                led_classdev_suspend(led_cdev);

        return 0;
}

static int led_resume(struct device *dev)
{
        struct led_classdev *led_cdev = dev_get_drvdata(dev);

        if (led_cdev->flags & LED_CORE_SUSPENDRESUME)
                led_classdev_resume(led_cdev);

        return 0;
}
#endif

static SIMPLE_DEV_PM_OPS(leds_class_dev_pm_ops, led_suspend, led_resume);

static struct led_classdev *led_module_get(struct device *led_dev)
{
        struct led_classdev *led_cdev;

        if (!led_dev)
                return ERR_PTR(-EPROBE_DEFER);

        led_cdev = dev_get_drvdata(led_dev);

        if (!try_module_get(led_cdev->dev->parent->driver->owner)) {
                put_device(led_cdev->dev);
                return ERR_PTR(-ENODEV);
        }

        return led_cdev;
}

static const struct class leds_class = {
        .name = "leds",
        .dev_groups = led_groups,
        .pm = &leds_class_dev_pm_ops,
};

/**
 * fwnode_led_get() - request a LED device via the LED framework
 * @fwnode: firmware node to get the LED device from
 * @index: the index of the LED
 * @name: the name of the LED used to map it to its function, if present
 *
 * Returns the LED device parsed from the phandle specified in the "leds"
 * property of a device tree node or a negative error-code on failure.
 */
static struct led_classdev *fwnode_led_get(struct fwnode_handle *fwnode,
                                           int index, const char *name)
{
        struct fwnode_handle *led_node;
        struct device *led_dev;

        /*
         * For named LEDs, first look up the name in the "led-names" property.
         * If it cannot be found, then fwnode_find_reference() will propagate
         * the error.
         */
        if (name)
                index = fwnode_property_match_string(fwnode, "led-names",
                                                     name);
        led_node = fwnode_find_reference(fwnode, "leds", index);
        if (IS_ERR(led_node))
                return ERR_CAST(led_node);

        led_dev = class_find_device_by_fwnode(&leds_class, led_node);
        fwnode_handle_put(led_node);

        return led_module_get(led_dev);
}

/**
 * led_put() - release a LED device
 * @led_cdev: LED device
 */
void led_put(struct led_classdev *led_cdev)
{
        module_put(led_cdev->dev->parent->driver->owner);
        put_device(led_cdev->dev);
}
EXPORT_SYMBOL_GPL(led_put);

static void devm_led_release(struct device *dev, void *res)
{
        struct led_classdev **p = res;

        led_put(*p);
}

static struct led_classdev *__devm_led_get(struct device *dev, struct led_classdev *led)
{
        struct led_classdev **dr;

        dr = devres_alloc(devm_led_release, sizeof(struct led_classdev *), GFP_KERNEL);
        if (!dr) {
                led_put(led);
                return ERR_PTR(-ENOMEM);
        }

        *dr = led;
        devres_add(dev, dr);

        return led;
}

/**
 * devm_of_led_get - Resource-managed request of a LED device
 * @dev:        LED consumer
 * @index:      index of the LED to obtain in the consumer
 *
 * The device node of the device is parse to find the request LED device.
 * The LED device returned from this function is automatically released
 * on driver detach.
 *
 * @return a pointer to a LED device or ERR_PTR(errno) on failure.
 */
struct led_classdev *__must_check devm_of_led_get(struct device *dev,
                                                  int index)
{
        struct led_classdev *led;

        if (!dev)
                return ERR_PTR(-EINVAL);

        led = fwnode_led_get(dev_fwnode(dev), index, NULL);
        if (IS_ERR(led))
                return led;

        return __devm_led_get(dev, led);
}
EXPORT_SYMBOL_GPL(devm_of_led_get);

/**
 * led_get() - request a LED device via the LED framework
 * @dev: device for which to get the LED device
 * @con_id: name of the LED from the device's point of view
 *
 * @return a pointer to a LED device or ERR_PTR(errno) on failure.
 */
struct led_classdev *led_get(struct device *dev, char *con_id)
{
        struct led_lookup_data *lookup;
        struct led_classdev *led_cdev;
        const char *provider = NULL;
        struct device *led_dev;

        led_cdev = fwnode_led_get(dev_fwnode(dev), -1, con_id);
        if (!IS_ERR(led_cdev) || PTR_ERR(led_cdev) != -ENOENT)
                return led_cdev;

        mutex_lock(&leds_lookup_lock);
        list_for_each_entry(lookup, &leds_lookup_list, list) {
                if (!strcmp(lookup->dev_id, dev_name(dev)) &&
                    !strcmp(lookup->con_id, con_id)) {
                        provider = kstrdup_const(lookup->provider, GFP_KERNEL);
                        break;
                }
        }
        mutex_unlock(&leds_lookup_lock);

        if (!provider)
                return ERR_PTR(-ENOENT);

        led_dev = class_find_device_by_name(&leds_class, provider);
        kfree_const(provider);

        return led_module_get(led_dev);
}
EXPORT_SYMBOL_GPL(led_get);

/**
 * devm_led_get() - request a LED device via the LED framework
 * @dev: device for which to get the LED device
 * @con_id: name of the LED from the device's point of view
 *
 * The LED device returned from this function is automatically released
 * on driver detach.
 *
 * @return a pointer to a LED device or ERR_PTR(errno) on failure.
 */
struct led_classdev *devm_led_get(struct device *dev, char *con_id)
{
        struct led_classdev *led;

        led = led_get(dev, con_id);
        if (IS_ERR(led))
                return led;

        return __devm_led_get(dev, led);
}
EXPORT_SYMBOL_GPL(devm_led_get);

/**
 * led_add_lookup() - Add a LED lookup table entry
 * @led_lookup: the lookup table entry to add
 *
 * Add a LED lookup table entry. On systems without devicetree the lookup table
 * is used by led_get() to find LEDs.
 */
void led_add_lookup(struct led_lookup_data *led_lookup)
{
        mutex_lock(&leds_lookup_lock);
        list_add_tail(&led_lookup->list, &leds_lookup_list);
        mutex_unlock(&leds_lookup_lock);
}
EXPORT_SYMBOL_GPL(led_add_lookup);

/**
 * led_remove_lookup() - Remove a LED lookup table entry
 * @led_lookup: the lookup table entry to remove
 */
void led_remove_lookup(struct led_lookup_data *led_lookup)
{
        if (!led_lookup)
                return;

        mutex_lock(&leds_lookup_lock);
        list_del(&led_lookup->list);
        mutex_unlock(&leds_lookup_lock);
}
EXPORT_SYMBOL_GPL(led_remove_lookup);

/**
 * devm_of_led_get_optional - Resource-managed request of an optional LED device
 * @dev:        LED consumer
 * @index:      index of the LED to obtain in the consumer
 *
 * The device node of the device is parsed to find the requested LED device.
 * The LED device returned from this function is automatically released
 * on driver detach.
 *
 * @return a pointer to a LED device, ERR_PTR(errno) on failure and NULL if the
 * led was not found.
 */
struct led_classdev *__must_check devm_of_led_get_optional(struct device *dev,
                                                        int index)
{
        struct led_classdev *led;

        led = devm_of_led_get(dev, index);
        if (IS_ERR(led) && PTR_ERR(led) == -ENOENT)
                return NULL;

        return led;
}
EXPORT_SYMBOL_GPL(devm_of_led_get_optional);

static int led_classdev_next_name(const char *init_name, char *name,
                                  size_t len)
{
        unsigned int i = 0;
        int ret = 0;
        struct device *dev;

        strscpy(name, init_name, len);

        while ((ret < len) &&
               (dev = class_find_device_by_name(&leds_class, name))) {
                put_device(dev);
                ret = snprintf(name, len, "%s_%u", init_name, ++i);
        }

        if (ret >= len)
                return -ENOMEM;

        return i;
}

/**
 * led_classdev_register_ext - register a new object of led_classdev class
 *                             with init data.
 *
 * @parent: parent of LED device
 * @led_cdev: the led_classdev structure for this device.
 * @init_data: LED class device initialization data
 */
int led_classdev_register_ext(struct device *parent,
                              struct led_classdev *led_cdev,
                              struct led_init_data *init_data)
{
        char composed_name[LED_MAX_NAME_SIZE];
        char final_name[LED_MAX_NAME_SIZE];
        const char *proposed_name = composed_name;
        int ret;

        if (init_data) {
                if (init_data->devname_mandatory && !init_data->devicename) {
                        dev_err(parent, "Mandatory device name is missing");
                        return -EINVAL;
                }
                ret = led_compose_name(parent, init_data, composed_name);
                if (ret < 0)
                        return ret;

                if (init_data->fwnode) {
                        fwnode_property_read_string(init_data->fwnode,
                                "linux,default-trigger",
                                &led_cdev->default_trigger);

                        if (fwnode_property_present(init_data->fwnode,
                                                    "retain-state-shutdown"))
                                led_cdev->flags |= LED_RETAIN_AT_SHUTDOWN;

                        fwnode_property_read_u32(init_data->fwnode,
                                "max-brightness",
                                &led_cdev->max_brightness);

                        if (fwnode_property_present(init_data->fwnode, "color"))
                                fwnode_property_read_u32(init_data->fwnode, "color",
                                                         &led_cdev->color);
                }
        } else {
                proposed_name = led_cdev->name;
        }

        ret = led_classdev_next_name(proposed_name, final_name, sizeof(final_name));
        if (ret < 0)
                return ret;
        else if (ret && led_cdev->flags & LED_REJECT_NAME_CONFLICT)
                return -EEXIST;
        else if (ret)
                dev_warn(parent, "Led %s renamed to %s due to name collision\n",
                         proposed_name, final_name);

        if (led_cdev->color >= LED_COLOR_ID_MAX)
                dev_warn(parent, "LED %s color identifier out of range\n", final_name);

        mutex_init(&led_cdev->led_access);
        mutex_lock(&led_cdev->led_access);
        led_cdev->dev = device_create_with_groups(&leds_class, parent, 0,
                                                  led_cdev, led_cdev->groups, "%s", final_name);
        if (IS_ERR(led_cdev->dev)) {
                mutex_unlock(&led_cdev->led_access);
                return PTR_ERR(led_cdev->dev);
        }
        if (init_data && init_data->fwnode)
                device_set_node(led_cdev->dev, init_data->fwnode);

        if (led_cdev->flags & LED_BRIGHT_HW_CHANGED) {
                ret = led_add_brightness_hw_changed(led_cdev);
                if (ret) {
                        device_unregister(led_cdev->dev);
                        led_cdev->dev = NULL;
                        mutex_unlock(&led_cdev->led_access);
                        return ret;
                }
        }

        led_cdev->work_flags = 0;
#ifdef CONFIG_LEDS_TRIGGERS
        init_rwsem(&led_cdev->trigger_lock);
#endif
#ifdef CONFIG_LEDS_BRIGHTNESS_HW_CHANGED
        led_cdev->brightness_hw_changed = -1;
#endif
        if (!led_cdev->max_brightness)
                led_cdev->max_brightness = LED_FULL;

        led_update_brightness(led_cdev);

        led_cdev->wq = leds_wq;

        led_init_core(led_cdev);

        /* add to the list of leds */
        down_write(&leds_list_lock);
        list_add_tail(&led_cdev->node, &leds_list);
        up_write(&leds_list_lock);

#ifdef CONFIG_LEDS_TRIGGERS
        led_trigger_set_default(led_cdev);
#endif

        mutex_unlock(&led_cdev->led_access);

        dev_dbg(parent, "Registered led device: %s\n",
                        led_cdev->name);

        return 0;
}
EXPORT_SYMBOL_GPL(led_classdev_register_ext);

/**
 * led_classdev_unregister - unregisters a object of led_properties class.
 * @led_cdev: the led device to unregister
 *
 * Unregisters a previously registered via led_classdev_register object.
 */
void led_classdev_unregister(struct led_classdev *led_cdev)
{
        if (IS_ERR_OR_NULL(led_cdev->dev))
                return;

#ifdef CONFIG_LEDS_TRIGGERS
        down_write(&led_cdev->trigger_lock);
        if (led_cdev->trigger)
                led_trigger_set(led_cdev, NULL);
        up_write(&led_cdev->trigger_lock);
#endif

        led_cdev->flags |= LED_UNREGISTERING;

        /* Stop blinking */
        led_stop_software_blink(led_cdev);

        if (!(led_cdev->flags & LED_RETAIN_AT_SHUTDOWN))
                led_set_brightness(led_cdev, LED_OFF);

        flush_work(&led_cdev->set_brightness_work);

        if (led_cdev->flags & LED_BRIGHT_HW_CHANGED)
                led_remove_brightness_hw_changed(led_cdev);

        device_unregister(led_cdev->dev);

        down_write(&leds_list_lock);
        list_del(&led_cdev->node);
        up_write(&leds_list_lock);

        mutex_destroy(&led_cdev->led_access);
}
EXPORT_SYMBOL_GPL(led_classdev_unregister);

static void devm_led_classdev_release(struct device *dev, void *res)
{
        led_classdev_unregister(*(struct led_classdev **)res);
}

/**
 * devm_led_classdev_register_ext - resource managed led_classdev_register_ext()
 *
 * @parent: parent of LED device
 * @led_cdev: the led_classdev structure for this device.
 * @init_data: LED class device initialization data
 */
int devm_led_classdev_register_ext(struct device *parent,
                                   struct led_classdev *led_cdev,
                                   struct led_init_data *init_data)
{
        struct led_classdev **dr;
        int rc;

        dr = devres_alloc(devm_led_classdev_release, sizeof(*dr), GFP_KERNEL);
        if (!dr)
                return -ENOMEM;

        rc = led_classdev_register_ext(parent, led_cdev, init_data);
        if (rc) {
                devres_free(dr);
                return rc;
        }

        *dr = led_cdev;
        devres_add(parent, dr);

        return 0;
}
EXPORT_SYMBOL_GPL(devm_led_classdev_register_ext);

static int devm_led_classdev_match(struct device *dev, void *res, void *data)
{
        struct led_classdev **p = res;

        if (WARN_ON(!p || !*p))
                return 0;

        return *p == data;
}

/**
 * devm_led_classdev_unregister() - resource managed led_classdev_unregister()
 * @dev: The device to unregister.
 * @led_cdev: the led_classdev structure for this device.
 */
void devm_led_classdev_unregister(struct device *dev,
                                  struct led_classdev *led_cdev)
{
        WARN_ON(devres_release(dev,
                               devm_led_classdev_release,
                               devm_led_classdev_match, led_cdev));
}
EXPORT_SYMBOL_GPL(devm_led_classdev_unregister);

static int __init leds_init(void)
{
        leds_wq = alloc_ordered_workqueue("leds", 0);
        if (!leds_wq) {
                pr_err("Failed to create LEDs ordered workqueue\n");
                return -ENOMEM;
        }

        return class_register(&leds_class);
}

static void __exit leds_exit(void)
{
        class_unregister(&leds_class);
        destroy_workqueue(leds_wq);
}

subsys_initcall(leds_init);
module_exit(leds_exit);

MODULE_AUTHOR("John Lenz, Richard Purdie");
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("LED Class Interface");