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
23#include <linux/kernel.h>
24#include <linux/errno.h>
25#include <linux/init.h>
26#include <linux/module.h>
27#include <linux/slab.h>
28#include <linux/usb.h>
29#include <linux/backlight.h>
30#include <linux/timer.h>
31#include <linux/workqueue.h>
32#include <linux/atomic.h>
33
34#define APPLE_VENDOR_ID		0x05AC
35
36#define USB_REQ_GET_REPORT	0x01
37#define USB_REQ_SET_REPORT	0x09
38
39#define ACD_USB_TIMEOUT		250
40
41#define ACD_USB_EDID		0x0302
42#define ACD_USB_BRIGHTNESS	0x0310
43
44#define ACD_BTN_NONE		0
45#define ACD_BTN_BRIGHT_UP	3
46#define ACD_BTN_BRIGHT_DOWN	4
47
48#define ACD_URB_BUFFER_LEN	2
49#define ACD_MSG_BUFFER_LEN	2
50
51#define APPLEDISPLAY_DEVICE(prod)				\
52	.match_flags = USB_DEVICE_ID_MATCH_DEVICE |		\
53		       USB_DEVICE_ID_MATCH_INT_CLASS |		\
54		       USB_DEVICE_ID_MATCH_INT_PROTOCOL,	\
55	.idVendor = APPLE_VENDOR_ID,				\
56	.idProduct = (prod),					\
57	.bInterfaceClass = USB_CLASS_HID,			\
58	.bInterfaceProtocol = 0x00
59
60/* table of devices that work with this driver */
61static const struct usb_device_id appledisplay_table[] = {
62	{ APPLEDISPLAY_DEVICE(0x9218) },
63	{ APPLEDISPLAY_DEVICE(0x9219) },
64	{ APPLEDISPLAY_DEVICE(0x921c) },
65	{ APPLEDISPLAY_DEVICE(0x921d) },
66	{ APPLEDISPLAY_DEVICE(0x9236) },
67
68	/* Terminating entry */
69	{ }
70};
71MODULE_DEVICE_TABLE(usb, appledisplay_table);
72
73/* Structure to hold all of our device specific stuff */
74struct appledisplay {
75	struct usb_device *udev;	/* usb device */
76	struct urb *urb;		/* usb request block */
77	struct backlight_device *bd;	/* backlight device */
78	u8 *urbdata;			/* interrupt URB data buffer */
79	u8 *msgdata;			/* control message data buffer */
80
81	struct delayed_work work;
82	int button_pressed;
83	spinlock_t lock;
84	struct mutex sysfslock;		/* concurrent read and write */
85};
86
87static atomic_t count_displays = ATOMIC_INIT(0);
88static struct workqueue_struct *wq;
89
90static void appledisplay_complete(struct urb *urb)
91{
92	struct appledisplay *pdata = urb->context;
93	struct device *dev = &pdata->udev->dev;
94	unsigned long flags;
95	int status = urb->status;
96	int retval;
97
98	switch (status) {
99	case 0:
100		/* success */
101		break;
102	case -EOVERFLOW:
103		dev_err(dev,
104			"OVERFLOW with data length %d, actual length is %d\n",
105			ACD_URB_BUFFER_LEN, pdata->urb->actual_length);
106	case -ECONNRESET:
107	case -ENOENT:
108	case -ESHUTDOWN:
109		/* This urb is terminated, clean up */
110		dev_dbg(dev, "%s - urb shuttingdown with status: %d\n",
111			__func__, status);
112		return;
113	default:
114		dev_dbg(dev, "%s - nonzero urb status received: %d\n",
115			__func__, status);
116		goto exit;
117	}
118
119	spin_lock_irqsave(&pdata->lock, flags);
120
121	switch(pdata->urbdata[1]) {
122	case ACD_BTN_BRIGHT_UP:
123	case ACD_BTN_BRIGHT_DOWN:
124		pdata->button_pressed = 1;
125		queue_delayed_work(wq, &pdata->work, 0);
126		break;
127	case ACD_BTN_NONE:
128	default:
129		pdata->button_pressed = 0;
130		break;
131	}
132
133	spin_unlock_irqrestore(&pdata->lock, flags);
134
135exit:
136	retval = usb_submit_urb(pdata->urb, GFP_ATOMIC);
137	if (retval) {
138		dev_err(dev, "%s - usb_submit_urb failed with result %d\n",
139			__func__, retval);
140	}
141}
142
143static int appledisplay_bl_update_status(struct backlight_device *bd)
144{
145	struct appledisplay *pdata = bl_get_data(bd);
146	int retval;
147
148	mutex_lock(&pdata->sysfslock);
149	pdata->msgdata[0] = 0x10;
150	pdata->msgdata[1] = bd->props.brightness;
151
152	retval = usb_control_msg(
153		pdata->udev,
154		usb_sndctrlpipe(pdata->udev, 0),
155		USB_REQ_SET_REPORT,
156		USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_INTERFACE,
157		ACD_USB_BRIGHTNESS,
158		0,
159		pdata->msgdata, 2,
160		ACD_USB_TIMEOUT);
161	mutex_unlock(&pdata->sysfslock);
162
163	return retval;
164}
165
166static int appledisplay_bl_get_brightness(struct backlight_device *bd)
167{
168	struct appledisplay *pdata = bl_get_data(bd);
169	int retval, brightness;
170
171	mutex_lock(&pdata->sysfslock);
172	retval = usb_control_msg(
173		pdata->udev,
174		usb_rcvctrlpipe(pdata->udev, 0),
175		USB_REQ_GET_REPORT,
176		USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE,
177		ACD_USB_BRIGHTNESS,
178		0,
179		pdata->msgdata, 2,
180		ACD_USB_TIMEOUT);
181	brightness = pdata->msgdata[1];
182	mutex_unlock(&pdata->sysfslock);
183
184	if (retval < 0)
185		return retval;
186	else
187		return brightness;
188}
189
190static const struct backlight_ops appledisplay_bl_data = {
191	.get_brightness	= appledisplay_bl_get_brightness,
192	.update_status	= appledisplay_bl_update_status,
193};
194
195static void appledisplay_work(struct work_struct *work)
196{
197	struct appledisplay *pdata =
198		container_of(work, struct appledisplay, work.work);
199	int retval;
200
201	retval = appledisplay_bl_get_brightness(pdata->bd);
202	if (retval >= 0)
203		pdata->bd->props.brightness = retval;
204
205	/* Poll again in about 125ms if there's still a button pressed */
206	if (pdata->button_pressed)
207		schedule_delayed_work(&pdata->work, HZ / 8);
208}
209
210static int appledisplay_probe(struct usb_interface *iface,
211	const struct usb_device_id *id)
212{
213	struct backlight_properties props;
214	struct appledisplay *pdata;
215	struct usb_device *udev = interface_to_usbdev(iface);
216	struct usb_host_interface *iface_desc;
217	struct usb_endpoint_descriptor *endpoint;
218	int int_in_endpointAddr = 0;
219	int i, retval = -ENOMEM, brightness;
220	char bl_name[20];
221
222	/* set up the endpoint information */
223	/* use only the first interrupt-in endpoint */
224	iface_desc = iface->cur_altsetting;
225	for (i = 0; i < iface_desc->desc.bNumEndpoints; i++) {
226		endpoint = &iface_desc->endpoint[i].desc;
227		if (!int_in_endpointAddr && usb_endpoint_is_int_in(endpoint)) {
228			/* we found an interrupt in endpoint */
229			int_in_endpointAddr = endpoint->bEndpointAddress;
230			break;
231		}
232	}
233	if (!int_in_endpointAddr) {
234		dev_err(&iface->dev, "Could not find int-in endpoint\n");
235		return -EIO;
236	}
237
238	/* allocate memory for our device state and initialize it */
239	pdata = kzalloc(sizeof(struct appledisplay), GFP_KERNEL);
240	if (!pdata) {
241		retval = -ENOMEM;
242		dev_err(&iface->dev, "Out of memory\n");
243		goto error;
244	}
245
246	pdata->udev = udev;
247
248	spin_lock_init(&pdata->lock);
249	INIT_DELAYED_WORK(&pdata->work, appledisplay_work);
250	mutex_init(&pdata->sysfslock);
251
252	/* Allocate buffer for control messages */
253	pdata->msgdata = kmalloc(ACD_MSG_BUFFER_LEN, GFP_KERNEL);
254	if (!pdata->msgdata) {
255		retval = -ENOMEM;
256		dev_err(&iface->dev,
257			"Allocating buffer for control messages failed\n");
258		goto error;
259	}
260
261	/* Allocate interrupt URB */
262	pdata->urb = usb_alloc_urb(0, GFP_KERNEL);
263	if (!pdata->urb) {
264		retval = -ENOMEM;
265		dev_err(&iface->dev, "Allocating URB failed\n");
266		goto error;
267	}
268
269	/* Allocate buffer for interrupt data */
270	pdata->urbdata = usb_alloc_coherent(pdata->udev, ACD_URB_BUFFER_LEN,
271		GFP_KERNEL, &pdata->urb->transfer_dma);
272	if (!pdata->urbdata) {
273		retval = -ENOMEM;
274		dev_err(&iface->dev, "Allocating URB buffer failed\n");
275		goto error;
276	}
277
278	/* Configure interrupt URB */
279	usb_fill_int_urb(pdata->urb, udev,
280		usb_rcvintpipe(udev, int_in_endpointAddr),
281		pdata->urbdata, ACD_URB_BUFFER_LEN, appledisplay_complete,
282		pdata, 1);
283	if (usb_submit_urb(pdata->urb, GFP_KERNEL)) {
284		retval = -EIO;
285		dev_err(&iface->dev, "Submitting URB failed\n");
286		goto error;
287	}
288
289	/* Register backlight device */
290	snprintf(bl_name, sizeof(bl_name), "appledisplay%d",
291		atomic_inc_return(&count_displays) - 1);
292	memset(&props, 0, sizeof(struct backlight_properties));
293	props.type = BACKLIGHT_RAW;
294	props.max_brightness = 0xff;
295	pdata->bd = backlight_device_register(bl_name, NULL, pdata,
296					      &appledisplay_bl_data, &props);
297	if (IS_ERR(pdata->bd)) {
298		dev_err(&iface->dev, "Backlight registration failed\n");
299		retval = PTR_ERR(pdata->bd);
300		goto error;
301	}
302
303	/* Try to get brightness */
304	brightness = appledisplay_bl_get_brightness(pdata->bd);
305
306	if (brightness < 0) {
307		retval = brightness;
308		dev_err(&iface->dev,
309			"Error while getting initial brightness: %d\n", retval);
310		goto error;
311	}
312
313	/* Set brightness in backlight device */
314	pdata->bd->props.brightness = brightness;
315
316	/* save our data pointer in the interface device */
317	usb_set_intfdata(iface, pdata);
318
319	printk(KERN_INFO "appledisplay: Apple Cinema Display connected\n");
320
321	return 0;
322
323error:
324	if (pdata) {
325		if (pdata->urb) {
326			usb_kill_urb(pdata->urb);
327			if (pdata->urbdata)
328				usb_free_coherent(pdata->udev, ACD_URB_BUFFER_LEN,
329					pdata->urbdata, pdata->urb->transfer_dma);
330			usb_free_urb(pdata->urb);
331		}
332		if (!IS_ERR(pdata->bd))
333			backlight_device_unregister(pdata->bd);
334		kfree(pdata->msgdata);
335	}
336	usb_set_intfdata(iface, NULL);
337	kfree(pdata);
338	return retval;
339}
340
341static void appledisplay_disconnect(struct usb_interface *iface)
342{
343	struct appledisplay *pdata = usb_get_intfdata(iface);
344
345	if (pdata) {
346		usb_kill_urb(pdata->urb);
347		cancel_delayed_work(&pdata->work);
348		backlight_device_unregister(pdata->bd);
349		usb_free_coherent(pdata->udev, ACD_URB_BUFFER_LEN,
350			pdata->urbdata, pdata->urb->transfer_dma);
351		usb_free_urb(pdata->urb);
352		kfree(pdata->msgdata);
353		kfree(pdata);
354	}
355
356	printk(KERN_INFO "appledisplay: Apple Cinema Display disconnected\n");
357}
358
359static struct usb_driver appledisplay_driver = {
360	.name		= "appledisplay",
361	.probe		= appledisplay_probe,
362	.disconnect	= appledisplay_disconnect,
363	.id_table	= appledisplay_table,
364};
365
366static int __init appledisplay_init(void)
367{
368	wq = create_singlethread_workqueue("appledisplay");
369	if (!wq) {
370		printk(KERN_ERR "appledisplay: Could not create work queue\n");
371		return -ENOMEM;
372	}
373
374	return usb_register(&appledisplay_driver);
375}
376
377static void __exit appledisplay_exit(void)
378{
379	flush_workqueue(wq);
380	destroy_workqueue(wq);
381	usb_deregister(&appledisplay_driver);
382}
383
384MODULE_AUTHOR("Michael Hanselmann");
385MODULE_DESCRIPTION("Apple Cinema Display driver");
386MODULE_LICENSE("GPL");
387
388module_init(appledisplay_init);
389module_exit(appledisplay_exit);
390