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/*

 * Backlight Lowlevel Control Abstraction

 *

 * Copyright (C) 2003,2004 Hewlett-Packard Company

 *

 */

#include <linux/module.h>

#include <linux/init.h>

#include <linux/device.h>

#include <linux/backlight.h>

#include <linux/notifier.h>

#include <linux/ctype.h>

#include <linux/err.h>

#include <linux/fb.h>

#ifdef CONFIG_PMAC_BACKLIGHT

#include <asm/backlight.h>

#endif

#if defined(CONFIG_FB) || (defined(CONFIG_FB_MODULE) && \

                           defined(CONFIG_BACKLIGHT_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 backlight power as well ...

 */

static int fb_notifier_callback(struct notifier_block *self,

                                unsigned long event, void *data)

{

        struct backlight_device *bd;

        struct fb_event *evdata = data;

        /* If we aren't interested in this event, skip it immediately ... */

        if (event != FB_EVENT_BLANK && event != FB_EVENT_CONBLANK)

                return 0;

        bd = container_of(self, struct backlight_device, fb_notif);

        mutex_lock(&bd->ops_lock);

        if (bd->ops)

                if (!bd->ops->check_fb ||

                    bd->ops->check_fb(evdata->info)) {

                        bd->props.fb_blank = *(int *)evdata->data;

                        backlight_update_status(bd);

                }

        mutex_unlock(&bd->ops_lock);

        return 0;

}

static int backlight_register_fb(struct backlight_device *bd)

{

        memset(&bd->fb_notif, 0, sizeof(bd->fb_notif));

        bd->fb_notif.notifier_call = fb_notifier_callback;

        return fb_register_client(&bd->fb_notif);

}

static void backlight_unregister_fb(struct backlight_device *bd)

{

        fb_unregister_client(&bd->fb_notif);

}

#else

static inline int backlight_register_fb(struct backlight_device *bd)

{

        return 0;

}

static inline void backlight_unregister_fb(struct backlight_device *bd)

{

}

#endif /* CONFIG_FB */

static ssize_t backlight_show_power(struct device *dev,

                struct device_attribute *attr,char *buf)

{

        struct backlight_device *bd = to_backlight_device(dev);

        return sprintf(buf, "%d\n", bd->props.power);

}

static ssize_t backlight_store_power(struct device *dev,

                struct device_attribute *attr, const char *buf, size_t count)

{

        int rc = -ENXIO;

        char *endp;

        struct backlight_device *bd = to_backlight_device(dev);

        int power = simple_strtoul(buf, &endp, 0);

        size_t size = endp - buf;

        if (*endp && isspace(*endp))

                size++;

        if (size != count)

                return -EINVAL;

        mutex_lock(&bd->ops_lock);

        if (bd->ops) {

                pr_debug("backlight: set power to %d\n", power);

                bd->props.power = power;

                backlight_update_status(bd);

                rc = count;

        }

        mutex_unlock(&bd->ops_lock);

        return rc;

}

static ssize_t backlight_show_brightness(struct device *dev,

                struct device_attribute *attr, char *buf)

{

        struct backlight_device *bd = to_backlight_device(dev);

        return sprintf(buf, "%d\n", bd->props.brightness);

}

static ssize_t backlight_store_brightness(struct device *dev,

                struct device_attribute *attr, const char *buf, size_t count)

{

        int rc = -ENXIO;

        char *endp;

        struct backlight_device *bd = to_backlight_device(dev);

        int brightness = simple_strtoul(buf, &endp, 0);

        size_t size = endp - buf;

        if (*endp && isspace(*endp))

                size++;

        if (size != count)

                return -EINVAL;

        mutex_lock(&bd->ops_lock);

        if (bd->ops) {

                if (brightness > bd->props.max_brightness)

                        rc = -EINVAL;

                else {

                        pr_debug("backlight: set brightness to %d\n",

                                 brightness);

                        bd->props.brightness = brightness;

                        backlight_update_status(bd);

                        rc = count;

                }

        }

        mutex_unlock(&bd->ops_lock);

        return rc;

}

static ssize_t backlight_show_max_brightness(struct device *dev,

                struct device_attribute *attr, char *buf)

{

        struct backlight_device *bd = to_backlight_device(dev);

        return sprintf(buf, "%d\n", bd->props.max_brightness);

}

static ssize_t backlight_show_actual_brightness(struct device *dev,

                struct device_attribute *attr, char *buf)

{

        int rc = -ENXIO;

        struct backlight_device *bd = to_backlight_device(dev);

        mutex_lock(&bd->ops_lock);

        if (bd->ops && bd->ops->get_brightness)

                rc = sprintf(buf, "%d\n", bd->ops->get_brightness(bd));

        mutex_unlock(&bd->ops_lock);

        return rc;

}

static struct class *backlight_class;

static void bl_device_release(struct device *dev)

{

        struct backlight_device *bd = to_backlight_device(dev);

        kfree(bd);

}

static struct device_attribute bl_device_attributes[] = {

        __ATTR(bl_power, 0644, backlight_show_power, backlight_store_power),

        __ATTR(brightness, 0644, backlight_show_brightness,

                     backlight_store_brightness),

        __ATTR(actual_brightness, 0444, backlight_show_actual_brightness,

                     NULL),

        __ATTR(max_brightness, 0444, backlight_show_max_brightness, NULL),

        __ATTR_NULL,

};

/**

 * backlight_device_register - create and register a new object of

 *   backlight_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 for private driver use. The

 *   methods may retrieve it by using bl_get_data(bd).

 * @ops: the backlight operations structure.

 *

 * Creates and registers new backlight device. Returns either an

 * ERR_PTR() or a pointer to the newly allocated device.

 */

struct backlight_device *backlight_device_register(const char *name,

                struct device *parent, void *devdata, struct backlight_ops *ops)

{

        struct backlight_device *new_bd;

        int rc;

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

        new_bd = kzalloc(sizeof(struct backlight_device), GFP_KERNEL);

        if (!new_bd)

                return ERR_PTR(-ENOMEM);

        mutex_init(&new_bd->update_lock);

        mutex_init(&new_bd->ops_lock);

        new_bd->dev.class = backlight_class;

        new_bd->dev.parent = parent;

        new_bd->dev.release = bl_device_release;

        strlcpy(new_bd->dev.bus_id, name, BUS_ID_SIZE);

        dev_set_drvdata(&new_bd->dev, devdata);

        rc = device_register(&new_bd->dev);

        if (rc) {

                kfree(new_bd);

                return ERR_PTR(rc);

        }

        rc = backlight_register_fb(new_bd);

        if (rc) {

                device_unregister(&new_bd->dev);

                return ERR_PTR(rc);

        }

        new_bd->ops = ops;

#ifdef CONFIG_PMAC_BACKLIGHT

        mutex_lock(&pmac_backlight_mutex);

        if (!pmac_backlight)

                pmac_backlight = new_bd;

        mutex_unlock(&pmac_backlight_mutex);

#endif

        return new_bd;

}

EXPORT_SYMBOL(backlight_device_register);

/**

 * backlight_device_unregister - unregisters a backlight device object.

 * @bd: the backlight device object to be unregistered and freed.

 *

 * Unregisters a previously registered via backlight_device_register object.

 */

void backlight_device_unregister(struct backlight_device *bd)

{

        if (!bd)

                return;

#ifdef CONFIG_PMAC_BACKLIGHT

        mutex_lock(&pmac_backlight_mutex);

        if (pmac_backlight == bd)

                pmac_backlight = NULL;

        mutex_unlock(&pmac_backlight_mutex);

#endif

        mutex_lock(&bd->ops_lock);

        bd->ops = NULL;

        mutex_unlock(&bd->ops_lock);

        backlight_unregister_fb(bd);

        device_unregister(&bd->dev);

}

EXPORT_SYMBOL(backlight_device_unregister);

static void __exit backlight_class_exit(void)

{

        class_destroy(backlight_class);

}

static int __init backlight_class_init(void)

{

        backlight_class = class_create(THIS_MODULE, "backlight");

        if (IS_ERR(backlight_class)) {

                printk(KERN_WARNING "Unable to create backlight class; errno = %ld\n",

                                PTR_ERR(backlight_class));

                return PTR_ERR(backlight_class);

        }

        backlight_class->dev_attrs = bl_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(backlight_class_init);

module_exit(backlight_class_exit);

MODULE_LICENSE("GPL");

MODULE_AUTHOR("Jamey Hicks <jamey.hicks@hp.com>, Andrew Zabolotny <zap@homelink.ru>");

MODULE_DESCRIPTION("Backlight Lowlevel Control Abstraction");