#include <linux/init.h>

#include <linux/module.h>
#include <linux/backlight.h>
#include <linux/usb.h>

#include <linux/kernel.h>
#include <linux/slab.h>

#include "usb-pkk-backlight.h"
static void urb_out_complete(struct urb *urb)
{
	return;
}

static int pkk_bl_get_brightness(struct backlight_device *bdev)
{
	struct pkk_bl_data *data = bl_get_data(bdev);

	//uint8_t *brightness = &bdev->props.brightness; //Not sure, that this is right
	uint8_t *brightness = &data->brightness;
	printk(KERN_INFO PKK_BL_DRIVER_NAME "Brightness get function called. Current brightness: %d.\n", *brightness);
	return *brightness;
}

static int pkk_bl_set_brightness(struct backlight_device *bdev)
{
	struct pkk_bl_data *data = bl_get_data(bdev);

	//uint8_t *brightness = &bdev->props.brightness; //Not sure, that this is right
	uint8_t *brightness = &data->brightness;
	unsigned char *transfer_buffer_out = data->transfer_buffer_out;
	int error = 0;
	printk("%s(): data->transfer_buffer_out = %p\n", __FUNCTION__, data->transfer_buffer_out);
	*brightness = bdev->props.brightness;
	printk(KERN_INFO PKK_BL_DRIVER_NAME "Brightness set function called. New brightness: %d.\n", *brightness);
	*transfer_buffer_out = PKK_BL_CMD_SET_BRIGHTNESS;
	transfer_buffer_out++;
	*transfer_buffer_out = *brightness;
	error = usb_submit_urb(data->urb, GFP_KERNEL);
	if (data->urb->status != 0 || error != 0) {
		printk(KERN_ERR PKK_BL_DRIVER_NAME "Urb submit failled. Urb status: %d. Usb_submit_urb returned:%d.\n",
		       data->urb->status, error);
	}
	return error;
}

static const struct backlight_ops pkk_bl_blops = {
	.update_status = pkk_bl_set_brightness,
	.get_brightness = pkk_bl_get_brightness,
};

static int pkk_bl_init_backlight(struct pkk_bl_data *data)	// I'm not sure that it should be static
{
	struct device *dev = &data->intf->dev;
	struct backlight_device *bdev;
	struct backlight_properties props;
	printk(KERN_INFO PKK_BL_DRIVER_NAME "Backlight device initialization...\n");
	if (data->intf == 0) {
		printk(KERN_ERR PKK_BL_DRIVER_NAME "%s(): no such interface\n", __FUNCTION__);
		return -ENODEV;
	}
	/* PicoLCD - There was sommething for hid_report */
	memset(&props, 0, sizeof(props));
	props.type = BACKLIGHT_RAW;	//I don't know what is it
	props.max_brightness = PKK_BL_MAX_BRIGHTNESS;
	printk("%s(): data->intf = %p\ndev = %p\ndata = %p\n", __FUNCTION__, data->intf, (void *)dev, data);
	printk("%s(): dev_name(dev) = %s\ndev = %p\ndata = %p\n", __FUNCTION__, dev_name(dev), (void *)dev, data);
	bdev = backlight_device_register(dev_name(dev), dev, data, &pkk_bl_blops, &props);
	if (IS_ERR(bdev)) {
		printk(KERN_ERR PKK_BL_DRIVER_NAME "Failed to register backlight.\n");
		return PTR_ERR(bdev);
	}
	bdev->props.brightness = PKK_BL_DEFAULT_BRIGHTNESS;
	data->bdev = bdev;
	pkk_bl_set_brightness(bdev);
	printk(KERN_INFO PKK_BL_DRIVER_NAME "Backlight device initialized.\n");
	return 0;
}

static void pkk_bl_exit_backlight(struct pkk_bl_data *data)	// I'm not sure that it should be static
{
	struct backlight_device *bdev = data->bdev;
	printk(KERN_INFO PKK_BL_DRIVER_NAME "Backlight device unregistering...\n");
	data->bdev = NULL;
	if (bdev)
		backlight_device_unregister(bdev);
	printk(KERN_INFO PKK_BL_DRIVER_NAME "Backlight device unregistered successfully.\n");
}

static int pkk_bl_probe(struct usb_interface *intf, const struct usb_device_id *id)
{
	struct pkk_bl_data *data;
	int error = 0;
	struct urb *urb;
	unsigned char *transfer_buffer_out;
	struct usb_device *udev = interface_to_usbdev(intf);

	if (intf == NULL) {
		printk(KERN_ERR "%s(): no such interface\n", __FUNCTION__);
		error = -ENODEV;
		goto err_nodev;
	}
	printk(KERN_INFO PKK_BL_DRIVER_NAME "Hardware probe...\n");

	/* Varibles initialization and assigments */
	data = kzalloc(sizeof(struct pkk_bl_data), GFP_KERNEL);
	if (data == NULL) {
		printk(KERN_ERR PKK_BL_DRIVER_NAME "Can't allocate space for device data.\n");
		error = -ENOMEM;
		goto err_no_cleanup;
	}

	/* PicoLCD - There was synchronization elements (initialization & using) */
	dev_set_drvdata(&intf->dev, data);
	printk("pkk_bl_probe: intf = %p\n", (void *)intf);
	printk("pkk_bl_probe: &intf->dev = %p\n", (void *)&intf->dev);

	/* Filling data structure */
	data->udev_id = (struct usb_device_id *)id;
	data->udev = udev;
	data->intf = intf;

	/* Modules initialization */
	urb = usb_alloc_urb(0, GFP_KERNEL);
	if (urb == NULL) {
		printk(KERN_ERR PKK_BL_DRIVER_NAME "Can't initializate urb.\n");
		goto err_exit_backlight;
	}
	data->urb = urb;
	transfer_buffer_out = kzalloc(sizeof(unsigned char) * PKK_BL_TRANSFER_BUFFER_OUT_SIZE, GFP_KERNEL);
	if (transfer_buffer_out == NULL) {
		printk(KERN_ERR PKK_BL_DRIVER_NAME "Can't allocate space for transfer buffer (out).\n");
		error = -ENOMEM;
		goto err_urb_cleanup;
	}

	data->transfer_buffer_out = transfer_buffer_out;
	error = pkk_bl_init_backlight(data);
	if (error) {
		pkk_bl_exit_backlight(data);
		printk(KERN_ERR PKK_BL_DRIVER_NAME "Can't initializate backlight device.\n");
		goto err_cleanup_data;
	}

    usb_fill_int_urb(urb, udev, usb_rcvintpipe(to_usb_device(&intf->dev), PKK_BL_OUT_ENDPOINT), transfer_buffer_out, PKK_BL_TRANSFER_BUFFER_OUT_SIZE, urb_out_complete, data, PKK_BL_OUT_INTERVAL);
	printk(KERN_INFO PKK_BL_DRIVER_NAME "Device activated and initialized.\n");
	return 0;
 err_cleanup_data:kfree(data);
 err_urb_cleanup:usb_free_urb(urb);
 err_exit_backlight:pkk_bl_exit_backlight(data);
 err_no_cleanup:
	//dev_set_drvdata(&intf->dev, NULL); - intf->dev->data Wasn't assigned in this step(dev_setdrvdata wasn't called
 err_nodev:
	return error;
}

static void pkk_bl_disconnect(struct usb_interface *intf)
{
	struct pkk_bl_data *data = dev_get_drvdata(&intf->dev);
	printk(KERN_INFO PKK_BL_DRIVER_NAME "Hardware remove...\n");

	/* PicoLCD - There was synchronization elements (removing & using) */
	pkk_bl_exit_backlight(data);
	dev_set_drvdata(&intf->dev, NULL);
	usb_free_urb(data->urb);
	kfree(data->transfer_buffer_out);
	kfree(data);
	printk(KERN_INFO PKK_BL_DRIVER_NAME "Device disconnected successfully.\n");
}

static struct usb_device_id pkk_bl_devices[] = {
	{ USB_DEVICE(USB_VENDOR_ID_PKK_BL, USB_DEVICE_ID_PKK_BL) },
	{}
};

MODULE_DEVICE_TABLE(usb, pkk_bl_devices);
static struct usb_driver pkk_bl_driver = {
	.name = "usb_pkk_backlight",
	.id_table = pkk_bl_devices,
	.probe = pkk_bl_probe,
	.disconnect = pkk_bl_disconnect,
};

module_usb_driver(pkk_bl_driver);
MODULE_DESCRIPTION("PKK USB backlight driver");
MODULE_LICENSE("GPL v2");
MODULE_AUTHOR("Dmitry Chepurovskiy <dm3chip@gmail.com>");