/*

 * 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 ... */

	switch (event) {

	case FB_EVENT_BLANK:

	case FB_EVENT_MODE_CHANGE:

	case FB_EVENT_MODE_CHANGE_ALL:

		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 (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 = -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;

	dev_set_name(&new_ld->dev, 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)) {

		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");