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/*

 * LCD Lowlevel Control Abstraction

 *

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

 *

 */

#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>

#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 ... */

        if (event != FB_EVENT_BLANK)

                return 0;

        ld = container_of(self, struct lcd_device, fb_notif);

        mutex_lock(&ld->ops_lock);

        if (ld->ops)

                if (!ld->ops->check_fb || ld->ops->check_fb(evdata->info))

                        ld->ops->set_power(ld, *(int *)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 = -ENXIO;

        char *endp;

        struct lcd_device *ld = to_lcd_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(&ld->ops_lock);

        if (ld->ops && ld->ops->set_power) {

                pr_debug("lcd: set power to %d\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 = -ENXIO;

        char *endp;

        struct lcd_device *ld = to_lcd_device(dev);

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

        size_t size = endp - buf;

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

                size++;

        if (size != count)

                return -EINVAL;

        mutex_lock(&ld->ops_lock);

        if (ld->ops && ld->ops->set_contrast) {

                pr_debug("lcd: set contrast to %d\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;

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

        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)) {

                printk(KERN_WARNING "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");