[linux-block.git] / drivers / usb / misc / appledisplay.c

/*
 * Apple Cinema Display driver
 *
 * Copyright (C) 2006  Michael Hanselmann (linux-kernel@hansmi.ch)
 *
 * Thanks to Caskey L. Dickson for his work with acdctl.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 */

#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/usb.h>
#include <linux/backlight.h>
#include <linux/timer.h>
#include <linux/workqueue.h>
#include <asm/atomic.h>

#define APPLE_VENDOR_ID		0x05AC

#define USB_REQ_GET_REPORT	0x01
#define USB_REQ_SET_REPORT	0x09

#define ACD_USB_TIMEOUT		250

#define ACD_USB_EDID		0x0302
#define ACD_USB_BRIGHTNESS	0x0310

#define ACD_BTN_NONE		0
#define ACD_BTN_BRIGHT_UP	3
#define ACD_BTN_BRIGHT_DOWN	4

#define ACD_URB_BUFFER_LEN	2
#define ACD_MSG_BUFFER_LEN	2

#define APPLEDISPLAY_DEVICE(prod)				\
	.match_flags = USB_DEVICE_ID_MATCH_DEVICE |		\
		       USB_DEVICE_ID_MATCH_INT_CLASS |		\
		       USB_DEVICE_ID_MATCH_INT_PROTOCOL,	\
	.idVendor = APPLE_VENDOR_ID,				\
	.idProduct = (prod),					\
	.bInterfaceClass = USB_CLASS_HID,			\
	.bInterfaceProtocol = 0x00

/* table of devices that work with this driver */
static struct usb_device_id appledisplay_table [] = {
	{ APPLEDISPLAY_DEVICE(0x9218) },
	{ APPLEDISPLAY_DEVICE(0x9219) },
	{ APPLEDISPLAY_DEVICE(0x921d) },

	/* Terminating entry */
	{ }
};
MODULE_DEVICE_TABLE(usb, appledisplay_table);

/* Structure to hold all of our device specific stuff */
struct appledisplay {
	struct usb_device *udev;	/* usb device */
	struct urb *urb;		/* usb request block */
	struct backlight_device *bd;	/* backlight device */
	char *urbdata;			/* interrupt URB data buffer */
	char *msgdata;			/* control message data buffer */

	struct delayed_work work;
	int button_pressed;
	spinlock_t lock;
};

static atomic_t count_displays = ATOMIC_INIT(0);
static struct workqueue_struct *wq;

static void appledisplay_complete(struct urb *urb)
{
	struct appledisplay *pdata = urb->context;
	unsigned long flags;
	int status = urb->status;
	int retval;

	switch (status) {
	case 0:
		/* success */
		break;
	case -EOVERFLOW:
		printk(KERN_ERR "appletouch: OVERFLOW with data "
			"length %d, actual length is %d\n",
			ACD_URB_BUFFER_LEN, pdata->urb->actual_length);
	case -ECONNRESET:
	case -ENOENT:
	case -ESHUTDOWN:
		/* This urb is terminated, clean up */
		dbg("%s - urb shuttingdown with status: %d",
			__func__, status);
		return;
	default:
		dbg("%s - nonzero urb status received: %d",
			__func__, status);
		goto exit;
	}

	spin_lock_irqsave(&pdata->lock, flags);

	switch(pdata->urbdata[1]) {
	case ACD_BTN_BRIGHT_UP:
	case ACD_BTN_BRIGHT_DOWN:
		pdata->button_pressed = 1;
		queue_delayed_work(wq, &pdata->work, 0);
		break;
	case ACD_BTN_NONE:
	default:
		pdata->button_pressed = 0;
		break;
	}

	spin_unlock_irqrestore(&pdata->lock, flags);

exit:
	retval = usb_submit_urb(pdata->urb, GFP_ATOMIC);
	if (retval) {
		err("%s - usb_submit_urb failed with result %d",
			__func__, retval);
	}
}

static int appledisplay_bl_update_status(struct backlight_device *bd)
{
	struct appledisplay *pdata = bl_get_data(bd);
	int retval;

	pdata->msgdata[0] = 0x10;
	pdata->msgdata[1] = bd->props.brightness;

	retval = usb_control_msg(
		pdata->udev,
		usb_sndctrlpipe(pdata->udev, 0),
		USB_REQ_SET_REPORT,
		USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_INTERFACE,
		ACD_USB_BRIGHTNESS,
		0,
		pdata->msgdata, 2,
		ACD_USB_TIMEOUT);

	return retval;
}

static int appledisplay_bl_get_brightness(struct backlight_device *bd)
{
	struct appledisplay *pdata = bl_get_data(bd);
	int retval;

	retval = usb_control_msg(
		pdata->udev,
		usb_rcvctrlpipe(pdata->udev, 0),
		USB_REQ_GET_REPORT,
		USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE,
		ACD_USB_BRIGHTNESS,
		0,
		pdata->msgdata, 2,
		ACD_USB_TIMEOUT);

	if (retval < 0)
		return retval;
	else
		return pdata->msgdata[1];
}

static struct backlight_ops appledisplay_bl_data = {
	.get_brightness	= appledisplay_bl_get_brightness,
	.update_status	= appledisplay_bl_update_status,
};

static void appledisplay_work(struct work_struct *work)
{
	struct appledisplay *pdata =
		container_of(work, struct appledisplay, work.work);
	int retval;

	retval = appledisplay_bl_get_brightness(pdata->bd);
	if (retval >= 0)
		pdata->bd->props.brightness = retval;

	/* Poll again in about 125ms if there's still a button pressed */
	if (pdata->button_pressed)
		schedule_delayed_work(&pdata->work, HZ / 8);
}

static int appledisplay_probe(struct usb_interface *iface,
	const struct usb_device_id *id)
{
	struct appledisplay *pdata;
	struct usb_device *udev = interface_to_usbdev(iface);
	struct usb_host_interface *iface_desc;
	struct usb_endpoint_descriptor *endpoint;
	int int_in_endpointAddr = 0;
	int i, retval = -ENOMEM, brightness;
	char bl_name[20];

	/* set up the endpoint information */
	/* use only the first interrupt-in endpoint */
	iface_desc = iface->cur_altsetting;
	for (i = 0; i < iface_desc->desc.bNumEndpoints; i++) {
		endpoint = &iface_desc->endpoint[i].desc;
		if (!int_in_endpointAddr && usb_endpoint_is_int_in(endpoint)) {
			/* we found an interrupt in endpoint */
			int_in_endpointAddr = endpoint->bEndpointAddress;
			break;
		}
	}
	if (!int_in_endpointAddr) {
		err("Could not find int-in endpoint");
		return -EIO;
	}

	/* allocate memory for our device state and initialize it */
	pdata = kzalloc(sizeof(struct appledisplay), GFP_KERNEL);
	if (!pdata) {
		retval = -ENOMEM;
		err("Out of memory");
		goto error;
	}

	pdata->udev = udev;

	spin_lock_init(&pdata->lock);
	INIT_DELAYED_WORK(&pdata->work, appledisplay_work);

	/* Allocate buffer for control messages */
	pdata->msgdata = kmalloc(ACD_MSG_BUFFER_LEN, GFP_KERNEL);
	if (!pdata->msgdata) {
		retval = -ENOMEM;
		err("appledisplay: Allocating buffer for control messages "
			"failed");
		goto error;
	}

	/* Allocate interrupt URB */
	pdata->urb = usb_alloc_urb(0, GFP_KERNEL);
	if (!pdata->urb) {
		retval = -ENOMEM;
		err("appledisplay: Allocating URB failed");
		goto error;
	}

	/* Allocate buffer for interrupt data */
	pdata->urbdata = usb_buffer_alloc(pdata->udev, ACD_URB_BUFFER_LEN,
		GFP_KERNEL, &pdata->urb->transfer_dma);
	if (!pdata->urbdata) {
		retval = -ENOMEM;
		err("appledisplay: Allocating URB buffer failed");
		goto error;
	}

	/* Configure interrupt URB */
	usb_fill_int_urb(pdata->urb, udev,
		usb_rcvintpipe(udev, int_in_endpointAddr),
		pdata->urbdata, ACD_URB_BUFFER_LEN, appledisplay_complete,
		pdata, 1);
	if (usb_submit_urb(pdata->urb, GFP_KERNEL)) {
		retval = -EIO;
		err("appledisplay: Submitting URB failed");
		goto error;
	}

	/* Register backlight device */
	snprintf(bl_name, sizeof(bl_name), "appledisplay%d",
		atomic_inc_return(&count_displays) - 1);
	pdata->bd = backlight_device_register(bl_name, NULL, pdata,
						&appledisplay_bl_data);
	if (IS_ERR(pdata->bd)) {
		err("appledisplay: Backlight registration failed");
		goto error;
	}

	pdata->bd->props.max_brightness = 0xff;

	/* Try to get brightness */
	brightness = appledisplay_bl_get_brightness(pdata->bd);

	if (brightness < 0) {
		retval = brightness;
		err("appledisplay: Error while getting initial brightness: %d", retval);
		goto error;
	}

	/* Set brightness in backlight device */
	pdata->bd->props.brightness = brightness;

	/* save our data pointer in the interface device */
	usb_set_intfdata(iface, pdata);

	printk(KERN_INFO "appledisplay: Apple Cinema Display connected\n");

	return 0;

error:
	if (pdata) {
		if (pdata->urb) {
			usb_kill_urb(pdata->urb);
			if (pdata->urbdata)
				usb_buffer_free(pdata->udev, ACD_URB_BUFFER_LEN,
					pdata->urbdata, pdata->urb->transfer_dma);
			usb_free_urb(pdata->urb);
		}
		if (pdata->bd)
			backlight_device_unregister(pdata->bd);
		kfree(pdata->msgdata);
	}
	usb_set_intfdata(iface, NULL);
	kfree(pdata);
	return retval;
}

static void appledisplay_disconnect(struct usb_interface *iface)
{
	struct appledisplay *pdata = usb_get_intfdata(iface);

	if (pdata) {
		usb_kill_urb(pdata->urb);
		cancel_delayed_work(&pdata->work);
		backlight_device_unregister(pdata->bd);
		usb_buffer_free(pdata->udev, ACD_URB_BUFFER_LEN,
			pdata->urbdata, pdata->urb->transfer_dma);
		usb_free_urb(pdata->urb);
		kfree(pdata->msgdata);
		kfree(pdata);
	}

	printk(KERN_INFO "appledisplay: Apple Cinema Display disconnected\n");
}

static struct usb_driver appledisplay_driver = {
	.name		= "appledisplay",
	.probe		= appledisplay_probe,
	.disconnect	= appledisplay_disconnect,
	.id_table	= appledisplay_table,
};

static int __init appledisplay_init(void)
{
	wq = create_singlethread_workqueue("appledisplay");
	if (!wq) {
		err("Could not create work queue\n");
		return -ENOMEM;
	}

	return usb_register(&appledisplay_driver);
}

static void __exit appledisplay_exit(void)
{
	flush_workqueue(wq);
	destroy_workqueue(wq);
	usb_deregister(&appledisplay_driver);
}

MODULE_AUTHOR("Michael Hanselmann");
MODULE_DESCRIPTION("Apple Cinema Display driver");
MODULE_LICENSE("GPL");

module_init(appledisplay_init);
module_exit(appledisplay_exit);
Commit	Line	Data
069e8a65	1	/*
	2	* Apple Cinema Display driver
	3	*
	4	* Copyright (C) 2006 Michael Hanselmann (linux-kernel@hansmi.ch)
	5	*
	6	* Thanks to Caskey L. Dickson for his work with acdctl.
	7	*
	8	* This program is free software; you can redistribute it and/or modify
	9	* it under the terms of the GNU General Public License as published by
	10	* the Free Software Foundation; either version 2 of the License, or
	11	* (at your option) any later version.
	12	*
	13	* This program is distributed in the hope that it will be useful,
	14	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	15	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	16	* GNU General Public License for more details.
	17	*
	18	* You should have received a copy of the GNU General Public License
	19	* along with this program; if not, write to the Free Software
	20	* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
	21	*/
	22
069e8a65	23	#include <linux/kernel.h>
	24	#include <linux/errno.h>
	25	#include <linux/init.h>
	26	#include <linux/module.h>
	27	#include <linux/usb.h>
	28	#include <linux/backlight.h>
	29	#include <linux/timer.h>
	30	#include <linux/workqueue.h>
	31	#include <asm/atomic.h>
069e8a65	32
	33	#define APPLE_VENDOR_ID 0x05AC
	34
	35	#define USB_REQ_GET_REPORT 0x01
	36	#define USB_REQ_SET_REPORT 0x09
	37
	38	#define ACD_USB_TIMEOUT 250
	39
	40	#define ACD_USB_EDID 0x0302
	41	#define ACD_USB_BRIGHTNESS 0x0310
	42
	43	#define ACD_BTN_NONE 0
	44	#define ACD_BTN_BRIGHT_UP 3
	45	#define ACD_BTN_BRIGHT_DOWN 4
	46
	47	#define ACD_URB_BUFFER_LEN 2
	48	#define ACD_MSG_BUFFER_LEN 2
	49
	50	#define APPLEDISPLAY_DEVICE(prod) \
	51	.match_flags = USB_DEVICE_ID_MATCH_DEVICE \| \
	52	USB_DEVICE_ID_MATCH_INT_CLASS \| \
	53	USB_DEVICE_ID_MATCH_INT_PROTOCOL, \
	54	.idVendor = APPLE_VENDOR_ID, \
	55	.idProduct = (prod), \
	56	.bInterfaceClass = USB_CLASS_HID, \
	57	.bInterfaceProtocol = 0x00
	58
	59	/* table of devices that work with this driver */
	60	static struct usb_device_id appledisplay_table [] = {
	61	{ APPLEDISPLAY_DEVICE(0x9218) },
	62	{ APPLEDISPLAY_DEVICE(0x9219) },
	63	{ APPLEDISPLAY_DEVICE(0x921d) },
	64
	65	/* Terminating entry */
	66	{ }
	67	};
	68	MODULE_DEVICE_TABLE(usb, appledisplay_table);
	69
	70	/* Structure to hold all of our device specific stuff */
	71	struct appledisplay {
	72	struct usb_device udev; / usb device */
	73	struct urb urb; / usb request block */
	74	struct backlight_device bd; / backlight device */
	75	char urbdata; / interrupt URB data buffer */
	76	char msgdata; / control message data buffer */
	77
6d5aefb8	78	struct delayed_work work;
069e8a65	79	int button_pressed;
	80	spinlock_t lock;
	81	};
	82
	83	static atomic_t count_displays = ATOMIC_INIT(0);
	84	static struct workqueue_struct *wq;
	85
7d12e780	86	static void appledisplay_complete(struct urb *urb)
069e8a65	87	{
	88	struct appledisplay *pdata = urb->context;
	89	unsigned long flags;
13f9782d	90	int status = urb->status;
069e8a65	91	int retval;
069e8a65	92
13f9782d	93	switch (status) {
069e8a65	94	case 0:
	95	/* success */
	96	break;
	97	case -EOVERFLOW:
	98	printk(KERN_ERR "appletouch: OVERFLOW with data "
	99	"length %d, actual length is %d\n",
	100	ACD_URB_BUFFER_LEN, pdata->urb->actual_length);
	101	case -ECONNRESET:
	102	case -ENOENT:
	103	case -ESHUTDOWN:
	104	/* This urb is terminated, clean up */
13f9782d	105	dbg("%s - urb shuttingdown with status: %d",
441b62c1	106	__func__, status);
069e8a65	107	return;
	108	default:
	109	dbg("%s - nonzero urb status received: %d",
441b62c1	110	__func__, status);
069e8a65	111	goto exit;
	112	}
	113
	114	spin_lock_irqsave(&pdata->lock, flags);
	115
	116	switch(pdata->urbdata[1]) {
	117	case ACD_BTN_BRIGHT_UP:
	118	case ACD_BTN_BRIGHT_DOWN:
	119	pdata->button_pressed = 1;
6d5aefb8	120	queue_delayed_work(wq, &pdata->work, 0);
069e8a65	121	break;
	122	case ACD_BTN_NONE:
	123	default:
	124	pdata->button_pressed = 0;
	125	break;
	126	}
	127
	128	spin_unlock_irqrestore(&pdata->lock, flags);
	129
	130	exit:
	131	retval = usb_submit_urb(pdata->urb, GFP_ATOMIC);
	132	if (retval) {
	133	err("%s - usb_submit_urb failed with result %d",
441b62c1	134	__func__, retval);
069e8a65	135	}
	136	}
	137
	138	static int appledisplay_bl_update_status(struct backlight_device *bd)
	139	{
655bfd7a	140	struct appledisplay *pdata = bl_get_data(bd);
069e8a65	141	int retval;
	142
	143	pdata->msgdata[0] = 0x10;
599a52d1	144	pdata->msgdata[1] = bd->props.brightness;
069e8a65	145
	146	retval = usb_control_msg(
	147	pdata->udev,
	148	usb_sndctrlpipe(pdata->udev, 0),
	149	USB_REQ_SET_REPORT,
	150	USB_DIR_OUT \| USB_TYPE_CLASS \| USB_RECIP_INTERFACE,
	151	ACD_USB_BRIGHTNESS,
	152	0,
	153	pdata->msgdata, 2,
	154	ACD_USB_TIMEOUT);
	155
	156	return retval;
	157	}
	158
	159	static int appledisplay_bl_get_brightness(struct backlight_device *bd)
	160	{
655bfd7a	161	struct appledisplay *pdata = bl_get_data(bd);
069e8a65	162	int retval;
	163
	164	retval = usb_control_msg(
	165	pdata->udev,
	166	usb_rcvctrlpipe(pdata->udev, 0),
	167	USB_REQ_GET_REPORT,
	168	USB_DIR_IN \| USB_TYPE_CLASS \| USB_RECIP_INTERFACE,
	169	ACD_USB_BRIGHTNESS,
	170	0,
	171	pdata->msgdata, 2,
	172	ACD_USB_TIMEOUT);
	173
	174	if (retval < 0)
	175	return retval;
	176	else
	177	return pdata->msgdata[1];
	178	}
	179
599a52d1	180	static struct backlight_ops appledisplay_bl_data = {
069e8a65	181	.get_brightness = appledisplay_bl_get_brightness,
069e8a65	182	.update_status = appledisplay_bl_update_status,
069e8a65	183	};
069e8a65	184
6d5aefb8	185	static void appledisplay_work(struct work_struct *work)
069e8a65	186	{
6d5aefb8 DH	187	struct appledisplay *pdata =
6d5aefb8 DH	188	container_of(work, struct appledisplay, work.work);
069e8a65	189	int retval;
069e8a65	190
069e8a65	191	retval = appledisplay_bl_get_brightness(pdata->bd);
069e8a65	192	if (retval >= 0)
599a52d1	193	pdata->bd->props.brightness = retval;
069e8a65	194
	195	/* Poll again in about 125ms if there's still a button pressed */
	196	if (pdata->button_pressed)
	197	schedule_delayed_work(&pdata->work, HZ / 8);
	198	}
	199
	200	static int appledisplay_probe(struct usb_interface *iface,
	201	const struct usb_device_id *id)
	202	{
	203	struct appledisplay *pdata;
	204	struct usb_device *udev = interface_to_usbdev(iface);
	205	struct usb_host_interface *iface_desc;
	206	struct usb_endpoint_descriptor *endpoint;
	207	int int_in_endpointAddr = 0;
	208	int i, retval = -ENOMEM, brightness;
	209	char bl_name[20];
	210
	211	/* set up the endpoint information */
	212	/* use only the first interrupt-in endpoint */
	213	iface_desc = iface->cur_altsetting;
	214	for (i = 0; i < iface_desc->desc.bNumEndpoints; i++) {
	215	endpoint = &iface_desc->endpoint[i].desc;
16f96376	216	if (!int_in_endpointAddr && usb_endpoint_is_int_in(endpoint)) {
069e8a65	217	/* we found an interrupt in endpoint */
	218	int_in_endpointAddr = endpoint->bEndpointAddress;
	219	break;
	220	}
	221	}
	222	if (!int_in_endpointAddr) {
	223	err("Could not find int-in endpoint");
	224	return -EIO;
	225	}
	226
	227	/* allocate memory for our device state and initialize it */
	228	pdata = kzalloc(sizeof(struct appledisplay), GFP_KERNEL);
	229	if (!pdata) {
	230	retval = -ENOMEM;
	231	err("Out of memory");
	232	goto error;
	233	}
	234
	235	pdata->udev = udev;
	236
	237	spin_lock_init(&pdata->lock);
6d5aefb8	238	INIT_DELAYED_WORK(&pdata->work, appledisplay_work);
069e8a65	239
	240	/* Allocate buffer for control messages */
	241	pdata->msgdata = kmalloc(ACD_MSG_BUFFER_LEN, GFP_KERNEL);
	242	if (!pdata->msgdata) {
	243	retval = -ENOMEM;
	244	err("appledisplay: Allocating buffer for control messages "
	245	"failed");
	246	goto error;
	247	}
	248
	249	/* Allocate interrupt URB */
	250	pdata->urb = usb_alloc_urb(0, GFP_KERNEL);
	251	if (!pdata->urb) {
	252	retval = -ENOMEM;
	253	err("appledisplay: Allocating URB failed");
	254	goto error;
	255	}
	256
	257	/* Allocate buffer for interrupt data */
	258	pdata->urbdata = usb_buffer_alloc(pdata->udev, ACD_URB_BUFFER_LEN,
	259	GFP_KERNEL, &pdata->urb->transfer_dma);
	260	if (!pdata->urbdata) {
	261	retval = -ENOMEM;
	262	err("appledisplay: Allocating URB buffer failed");
	263	goto error;
	264	}
	265
	266	/* Configure interrupt URB */
	267	usb_fill_int_urb(pdata->urb, udev,
	268	usb_rcvintpipe(udev, int_in_endpointAddr),
	269	pdata->urbdata, ACD_URB_BUFFER_LEN, appledisplay_complete,
	270	pdata, 1);
	271	if (usb_submit_urb(pdata->urb, GFP_KERNEL)) {
	272	retval = -EIO;
	273	err("appledisplay: Submitting URB failed");
	274	goto error;
	275	}
	276
	277	/* Register backlight device */
	278	snprintf(bl_name, sizeof(bl_name), "appledisplay%d",
	279	atomic_inc_return(&count_displays) - 1);
81450b73	280	pdata->bd = backlight_device_register(bl_name, NULL, pdata,
069e8a65	281	&appledisplay_bl_data);
	282	if (IS_ERR(pdata->bd)) {
	283	err("appledisplay: Backlight registration failed");
	284	goto error;
	285	}
	286
599a52d1 RP	287	pdata->bd->props.max_brightness = 0xff;
599a52d1 RP	288
069e8a65	289	/* Try to get brightness */
069e8a65	290	brightness = appledisplay_bl_get_brightness(pdata->bd);
069e8a65	291
	292	if (brightness < 0) {
	293	retval = brightness;
	294	err("appledisplay: Error while getting initial brightness: %d", retval);
	295	goto error;
	296	}
	297
	298	/* Set brightness in backlight device */
599a52d1	299	pdata->bd->props.brightness = brightness;
069e8a65	300
	301	/* save our data pointer in the interface device */
	302	usb_set_intfdata(iface, pdata);
	303
	304	printk(KERN_INFO "appledisplay: Apple Cinema Display connected\n");
	305
	306	return 0;
	307
	308	error:
	309	if (pdata) {
	310	if (pdata->urb) {
	311	usb_kill_urb(pdata->urb);
	312	if (pdata->urbdata)
	313	usb_buffer_free(pdata->udev, ACD_URB_BUFFER_LEN,
	314	pdata->urbdata, pdata->urb->transfer_dma);
	315	usb_free_urb(pdata->urb);
	316	}
	317	if (pdata->bd)
	318	backlight_device_unregister(pdata->bd);
	319	kfree(pdata->msgdata);
	320	}
	321	usb_set_intfdata(iface, NULL);
	322	kfree(pdata);
	323	return retval;
	324	}
	325
	326	static void appledisplay_disconnect(struct usb_interface *iface)
	327	{
	328	struct appledisplay *pdata = usb_get_intfdata(iface);
	329
	330	if (pdata) {
	331	usb_kill_urb(pdata->urb);
	332	cancel_delayed_work(&pdata->work);
	333	backlight_device_unregister(pdata->bd);
	334	usb_buffer_free(pdata->udev, ACD_URB_BUFFER_LEN,
	335	pdata->urbdata, pdata->urb->transfer_dma);
	336	usb_free_urb(pdata->urb);
	337	kfree(pdata->msgdata);
	338	kfree(pdata);
	339	}
	340
	341	printk(KERN_INFO "appledisplay: Apple Cinema Display disconnected\n");
	342	}
	343
	344	static struct usb_driver appledisplay_driver = {
	345	.name = "appledisplay",
	346	.probe = appledisplay_probe,
	347	.disconnect = appledisplay_disconnect,
	348	.id_table = appledisplay_table,
	349	};
	350
	351	static int __init appledisplay_init(void)
	352	{
	353	wq = create_singlethread_workqueue("appledisplay");
	354	if (!wq) {
	355	err("Could not create work queue\n");
	356	return -ENOMEM;
	357	}
	358
	359	return usb_register(&appledisplay_driver);
	360	}
	361
	362	static void __exit appledisplay_exit(void)
	363	{
364	flush_workqueue(wq);
365	destroy_workqueue(wq);
366	usb_deregister(&appledisplay_driver);
367	}
368
369	MODULE_AUTHOR("Michael Hanselmann");
370	MODULE_DESCRIPTION("Apple Cinema Display driver");
371	MODULE_LICENSE("GPL");
372
373	module_init(appledisplay_init);
374	module_exit(appledisplay_exit);