// 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/slab.h>
#include <linux/spinlock.h>
#include <linux/timer.h>
#include <uapi/linux/uleds.h>
#include "leds.h"

static struct class *leds_class;

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

        /* no lock needed for this */
        led_update_brightness(led_cdev);

        return sprintf(buf, "%u\n", led_cdev->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);
        flush_work(&led_cdev->set_brightness_work);

        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);

        return sprintf(buf, "%u\n", led_cdev->max_brightness);
}
static DEVICE_ATTR_RO(max_brightness);

#ifdef CONFIG_LEDS_TRIGGERS
static DEVICE_ATTR(trigger, 0644, led_trigger_show, led_trigger_store);
static struct attribute *led_trigger_attrs[] = {
        &dev_attr_trigger.attr,
        NULL,
};
static const struct attribute_group led_trigger_group = {
        .attrs = led_trigger_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 sprintf(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,
                                               enum led_brightness 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);
}
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 int match_name(struct device *dev, const void *data)
{
        if (!dev_name(dev))
                return 0;
        return !strcmp(dev_name(dev), (char *)data);
}

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;

        strlcpy(name, init_name, len);

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

        if (ret >= len)
                return -ENOMEM;

        return i;
}

/**
 * of_led_classdev_register - register a new object of led_classdev class.
 *
 * @parent: parent of LED device
 * @led_cdev: the led_classdev structure for this device.
 * @np: DT node describing this LED
 */
int of_led_classdev_register(struct device *parent, struct device_node *np,
                            struct led_classdev *led_cdev)
{
        char name[LED_MAX_NAME_SIZE];
        int ret;

        ret = led_classdev_next_name(led_cdev->name, name, sizeof(name));
        if (ret < 0)
                return ret;

        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", name);
        if (IS_ERR(led_cdev->dev)) {
                mutex_unlock(&led_cdev->led_access);
                return PTR_ERR(led_cdev->dev);
        }
        led_cdev->dev->of_node = np;

        if (ret)
                dev_warn(parent, "Led %s renamed to %s due to name collision",
                                led_cdev->name, dev_name(led_cdev->dev));

        if (led_cdev->flags & LED_BRIGHT_HW_CHANGED) {
                ret = led_add_brightness_hw_changed(led_cdev);
                if (ret) {
                        device_unregister(led_cdev->dev);
                        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
        /* add to the list of leds */
        down_write(&leds_list_lock);
        list_add_tail(&led_cdev->node, &leds_list);
        up_write(&leds_list_lock);

        if (!led_cdev->max_brightness)
                led_cdev->max_brightness = LED_FULL;

        led_update_brightness(led_cdev);

        led_init_core(led_cdev);

#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(of_led_classdev_register);

/**
 * 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)
{
#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);

        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_of_led_classdev_register - resource managed led_classdev_register()
 *
 * @parent: parent of LED device
 * @led_cdev: the led_classdev structure for this device.
 */
int devm_of_led_classdev_register(struct device *parent,
                                  struct device_node *np,
                                  struct led_classdev *led_cdev)
{
        struct led_classdev **dr;
        int rc;

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

        rc = of_led_classdev_register(parent, np, led_cdev);
        if (rc) {
                devres_free(dr);
                return rc;
        }

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

        return 0;
}
EXPORT_SYMBOL_GPL(devm_of_led_classdev_register);

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

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

        return *p == data;
}

/**
 * devm_led_classdev_unregister() - resource managed led_classdev_unregister()
 * @parent: 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_class = class_create(THIS_MODULE, "leds");
        if (IS_ERR(leds_class))
                return PTR_ERR(leds_class);
        leds_class->pm = &leds_class_dev_pm_ops;
        leds_class->dev_groups = led_groups;
        return 0;
}

static void __exit leds_exit(void)
{
        class_destroy(leds_class);
}

subsys_initcall(leds_init);
module_exit(leds_exit);

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