/*
 * LCD Lowlevel Control Abstraction
 *
 * Copyright (C) 2003,2004 Hewlett-Packard Company
 *
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/module.h>
#include <linux/init.h>
#include <linux/device.h>
#include <linux/lcd.h>
#include <linux/notifier.h>
#include <linux/ctype.h>
#include <linux/err.h>
#include <linux/fb.h>
#include <linux/slab.h>

#if defined(CONFIG_FB) || (defined(CONFIG_FB_MODULE) && \
                           defined(CONFIG_LCD_CLASS_DEVICE_MODULE))
/* This callback gets called when something important happens inside a
 * framebuffer driver. We're looking if that important event is blanking,
 * and if it is, we're switching lcd power as well ...
 */
static int fb_notifier_callback(struct notifier_block *self,
                                 unsigned long event, void *data)
{
        struct lcd_device *ld;
        struct fb_event *evdata = data;

        /* If we aren't interested in this event, skip it immediately ... */
        switch (event) {
        case FB_EVENT_BLANK:
        case FB_EVENT_MODE_CHANGE:
        case FB_EVENT_MODE_CHANGE_ALL:
        case FB_EARLY_EVENT_BLANK:
        case FB_R_EARLY_EVENT_BLANK:
                break;
        default:
                return 0;
        }

        ld = container_of(self, struct lcd_device, fb_notif);
        if (!ld->ops)
                return 0;

        mutex_lock(&ld->ops_lock);
        if (!ld->ops->check_fb || ld->ops->check_fb(ld, evdata->info)) {
                if (event == FB_EVENT_BLANK) {
                        if (ld->ops->set_power)
                                ld->ops->set_power(ld, *(int *)evdata->data);
                } else if (event == FB_EARLY_EVENT_BLANK) {
                        if (ld->ops->early_set_power)
                                ld->ops->early_set_power(ld,
                                                *(int *)evdata->data);
                } else if (event == FB_R_EARLY_EVENT_BLANK) {
                        if (ld->ops->r_early_set_power)
                                ld->ops->r_early_set_power(ld,
                                                *(int *)evdata->data);
                } else {
                        if (ld->ops->set_mode)
                                ld->ops->set_mode(ld, evdata->data);
                }
        }
        mutex_unlock(&ld->ops_lock);
        return 0;
}

static int lcd_register_fb(struct lcd_device *ld)
{
        memset(&ld->fb_notif, 0, sizeof(ld->fb_notif));
        ld->fb_notif.notifier_call = fb_notifier_callback;
        return fb_register_client(&ld->fb_notif);
}

static void lcd_unregister_fb(struct lcd_device *ld)
{
        fb_unregister_client(&ld->fb_notif);
}
#else
static int lcd_register_fb(struct lcd_device *ld)
{
        return 0;
}

static inline void lcd_unregister_fb(struct lcd_device *ld)
{
}
#endif /* CONFIG_FB */

static ssize_t lcd_show_power(struct device *dev, struct device_attribute *attr,
                char *buf)
{
        int rc;
        struct lcd_device *ld = to_lcd_device(dev);

        mutex_lock(&ld->ops_lock);
        if (ld->ops && ld->ops->get_power)
                rc = sprintf(buf, "%d\n", ld->ops->get_power(ld));
        else
                rc = -ENXIO;
        mutex_unlock(&ld->ops_lock);

        return rc;
}

static ssize_t lcd_store_power(struct device *dev,
                struct device_attribute *attr, const char *buf, size_t count)
{
        int rc;
        struct lcd_device *ld = to_lcd_device(dev);
        unsigned long power;

        rc = kstrtoul(buf, 0, &power);
        if (rc)
                return rc;

        rc = -ENXIO;

        mutex_lock(&ld->ops_lock);
        if (ld->ops && ld->ops->set_power) {
                pr_debug("set power to %lu\n", power);
                ld->ops->set_power(ld, power);
                rc = count;
        }
        mutex_unlock(&ld->ops_lock);

        return rc;
}

static ssize_t lcd_show_contrast(struct device *dev,
                struct device_attribute *attr, char *buf)
{
        int rc = -ENXIO;
        struct lcd_device *ld = to_lcd_device(dev);

        mutex_lock(&ld->ops_lock);
        if (ld->ops && ld->ops->get_contrast)
                rc = sprintf(buf, "%d\n", ld->ops->get_contrast(ld));
        mutex_unlock(&ld->ops_lock);

        return rc;
}

static ssize_t lcd_store_contrast(struct device *dev,
                struct device_attribute *attr, const char *buf, size_t count)
{
        int rc;
        struct lcd_device *ld = to_lcd_device(dev);
        unsigned long contrast;

        rc = kstrtoul(buf, 0, &contrast);
        if (rc)
                return rc;

        rc = -ENXIO;

        mutex_lock(&ld->ops_lock);
        if (ld->ops && ld->ops->set_contrast) {
                pr_debug("set contrast to %lu\n", contrast);
                ld->ops->set_contrast(ld, contrast);
                rc = count;
        }
        mutex_unlock(&ld->ops_lock);

        return rc;
}

static ssize_t lcd_show_max_contrast(struct device *dev,
                struct device_attribute *attr, char *buf)
{
        struct lcd_device *ld = to_lcd_device(dev);

        return sprintf(buf, "%d\n", ld->props.max_contrast);
}

static struct class *lcd_class;

static void lcd_device_release(struct device *dev)
{
        struct lcd_device *ld = to_lcd_device(dev);
        kfree(ld);
}

static struct device_attribute lcd_device_attributes[] = {
        __ATTR(lcd_power, 0644, lcd_show_power, lcd_store_power),
        __ATTR(contrast, 0644, lcd_show_contrast, lcd_store_contrast),
        __ATTR(max_contrast, 0444, lcd_show_max_contrast, NULL),
        __ATTR_NULL,
};

/**
 * lcd_device_register - register a new object of lcd_device class.
 * @name: the name of the new object(must be the same as the name of the
 *   respective framebuffer device).
 * @devdata: an optional pointer to be stored in the device. The
 *   methods may retrieve it by using lcd_get_data(ld).
 * @ops: the lcd operations structure.
 *
 * Creates and registers a new lcd device. Returns either an ERR_PTR()
 * or a pointer to the newly allocated device.
 */
struct lcd_device *lcd_device_register(const char *name, struct device *parent,
                void *devdata, struct lcd_ops *ops)
{
        struct lcd_device *new_ld;
        int rc;

        pr_debug("lcd_device_register: name=%s\n", name);

        new_ld = kzalloc(sizeof(struct lcd_device), GFP_KERNEL);
        if (!new_ld)
                return ERR_PTR(-ENOMEM);

        mutex_init(&new_ld->ops_lock);
        mutex_init(&new_ld->update_lock);

        new_ld->dev.class = lcd_class;
        new_ld->dev.parent = parent;
        new_ld->dev.release = lcd_device_release;
        dev_set_name(&new_ld->dev, "%s", name);
        dev_set_drvdata(&new_ld->dev, devdata);

        rc = device_register(&new_ld->dev);
        if (rc) {
                kfree(new_ld);
                return ERR_PTR(rc);
        }

        rc = lcd_register_fb(new_ld);
        if (rc) {
                device_unregister(&new_ld->dev);
                return ERR_PTR(rc);
        }

        new_ld->ops = ops;

        return new_ld;
}
EXPORT_SYMBOL(lcd_device_register);

/**
 * lcd_device_unregister - unregisters a object of lcd_device class.
 * @ld: the lcd device object to be unregistered and freed.
 *
 * Unregisters a previously registered via lcd_device_register object.
 */
void lcd_device_unregister(struct lcd_device *ld)
{
        if (!ld)
                return;

        mutex_lock(&ld->ops_lock);
        ld->ops = NULL;
        mutex_unlock(&ld->ops_lock);
        lcd_unregister_fb(ld);

        device_unregister(&ld->dev);
}
EXPORT_SYMBOL(lcd_device_unregister);

static void __exit lcd_class_exit(void)
{
        class_destroy(lcd_class);
}

static int __init lcd_class_init(void)
{
        lcd_class = class_create(THIS_MODULE, "lcd");
        if (IS_ERR(lcd_class)) {
                pr_warn("Unable to create backlight class; errno = %ld\n",
                        PTR_ERR(lcd_class));
                return PTR_ERR(lcd_class);
        }

        lcd_class->dev_attrs = lcd_device_attributes;
        return 0;
}

/*
 * if this is compiled into the kernel, we need to ensure that the
 * class is registered before users of the class try to register lcd's
 */
postcore_initcall(lcd_class_init);
module_exit(lcd_class_exit);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Jamey Hicks <jamey.hicks@hp.com>, Andrew Zabolotny <zap@homelink.ru>");
MODULE_DESCRIPTION("LCD Lowlevel Control Abstraction");