1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3 * Apple Cinema Display driver
4 *
5 * Copyright (C) 2006 Michael Hanselmann (linux-kernel@hansmi.ch)
6 *
7 * Thanks to Caskey L. Dickson for his work with acdctl.
8 */
9
10 #include <linux/kernel.h>
11 #include <linux/errno.h>
12 #include <linux/init.h>
13 #include <linux/module.h>
14 #include <linux/slab.h>
15 #include <linux/usb.h>
16 #include <linux/backlight.h>
17 #include <linux/timer.h>
18 #include <linux/workqueue.h>
19 #include <linux/atomic.h>
20
21 #define APPLE_VENDOR_ID 0x05AC
22
23 #define USB_REQ_GET_REPORT 0x01
24 #define USB_REQ_SET_REPORT 0x09
25
26 #define ACD_USB_TIMEOUT 250
27
28 #define ACD_USB_EDID 0x0302
29 #define ACD_USB_BRIGHTNESS 0x0310
30
31 #define ACD_BTN_NONE 0
32 #define ACD_BTN_BRIGHT_UP 3
33 #define ACD_BTN_BRIGHT_DOWN 4
34
35 #define ACD_URB_BUFFER_LEN 2
36 #define ACD_MSG_BUFFER_LEN 2
37
38 #define APPLEDISPLAY_DEVICE(prod) \
39 .match_flags = USB_DEVICE_ID_MATCH_DEVICE | \
40 USB_DEVICE_ID_MATCH_INT_CLASS | \
41 USB_DEVICE_ID_MATCH_INT_PROTOCOL, \
42 .idVendor = APPLE_VENDOR_ID, \
43 .idProduct = (prod), \
44 .bInterfaceClass = USB_CLASS_HID, \
45 .bInterfaceProtocol = 0x00
46
47 /* table of devices that work with this driver */
48 static const struct usb_device_id appledisplay_table[] = {
49 { APPLEDISPLAY_DEVICE(0x9218) },
50 { APPLEDISPLAY_DEVICE(0x9219) },
51 { APPLEDISPLAY_DEVICE(0x921c) },
52 { APPLEDISPLAY_DEVICE(0x921d) },
53 { APPLEDISPLAY_DEVICE(0x9222) },
54 { APPLEDISPLAY_DEVICE(0x9226) },
55 { APPLEDISPLAY_DEVICE(0x9236) },
56
57 /* Terminating entry */
58 { }
59 };
60 MODULE_DEVICE_TABLE(usb, appledisplay_table);
61
62 /* Structure to hold all of our device specific stuff */
63 struct appledisplay {
64 struct usb_device *udev; /* usb device */
65 struct urb *urb; /* usb request block */
66 struct backlight_device *bd; /* backlight device */
67 u8 *urbdata; /* interrupt URB data buffer */
68 u8 *msgdata; /* control message data buffer */
69
70 struct delayed_work work;
71 int button_pressed;
72 spinlock_t lock;
73 struct mutex sysfslock; /* concurrent read and write */
74 };
75
76 static atomic_t count_displays = ATOMIC_INIT(0);
77
appledisplay_complete(struct urb * urb)78 static void appledisplay_complete(struct urb *urb)
79 {
80 struct appledisplay *pdata = urb->context;
81 struct device *dev = &pdata->udev->dev;
82 unsigned long flags;
83 int status = urb->status;
84 int retval;
85
86 switch (status) {
87 case 0:
88 /* success */
89 break;
90 case -EOVERFLOW:
91 dev_err(dev,
92 "OVERFLOW with data length %d, actual length is %d\n",
93 ACD_URB_BUFFER_LEN, pdata->urb->actual_length);
94 /* fall through */
95 case -ECONNRESET:
96 case -ENOENT:
97 case -ESHUTDOWN:
98 /* This urb is terminated, clean up */
99 dev_dbg(dev, "%s - urb shuttingdown with status: %d\n",
100 __func__, status);
101 return;
102 default:
103 dev_dbg(dev, "%s - nonzero urb status received: %d\n",
104 __func__, status);
105 goto exit;
106 }
107
108 spin_lock_irqsave(&pdata->lock, flags);
109
110 switch(pdata->urbdata[1]) {
111 case ACD_BTN_BRIGHT_UP:
112 case ACD_BTN_BRIGHT_DOWN:
113 pdata->button_pressed = 1;
114 schedule_delayed_work(&pdata->work, 0);
115 break;
116 case ACD_BTN_NONE:
117 default:
118 pdata->button_pressed = 0;
119 break;
120 }
121
122 spin_unlock_irqrestore(&pdata->lock, flags);
123
124 exit:
125 retval = usb_submit_urb(pdata->urb, GFP_ATOMIC);
126 if (retval) {
127 dev_err(dev, "%s - usb_submit_urb failed with result %d\n",
128 __func__, retval);
129 }
130 }
131
appledisplay_bl_update_status(struct backlight_device * bd)132 static int appledisplay_bl_update_status(struct backlight_device *bd)
133 {
134 struct appledisplay *pdata = bl_get_data(bd);
135 int retval;
136
137 mutex_lock(&pdata->sysfslock);
138 pdata->msgdata[0] = 0x10;
139 pdata->msgdata[1] = bd->props.brightness;
140
141 retval = usb_control_msg(
142 pdata->udev,
143 usb_sndctrlpipe(pdata->udev, 0),
144 USB_REQ_SET_REPORT,
145 USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_INTERFACE,
146 ACD_USB_BRIGHTNESS,
147 0,
148 pdata->msgdata, 2,
149 ACD_USB_TIMEOUT);
150 mutex_unlock(&pdata->sysfslock);
151
152 if (retval < 0)
153 return retval;
154 else
155 return 0;
156 }
157
appledisplay_bl_get_brightness(struct backlight_device * bd)158 static int appledisplay_bl_get_brightness(struct backlight_device *bd)
159 {
160 struct appledisplay *pdata = bl_get_data(bd);
161 int retval, brightness;
162
163 mutex_lock(&pdata->sysfslock);
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 if (retval < 2) {
174 if (retval >= 0)
175 retval = -EMSGSIZE;
176 } else {
177 brightness = pdata->msgdata[1];
178 }
179 mutex_unlock(&pdata->sysfslock);
180
181 if (retval < 0)
182 return retval;
183 else
184 return brightness;
185 }
186
187 static const struct backlight_ops appledisplay_bl_data = {
188 .get_brightness = appledisplay_bl_get_brightness,
189 .update_status = appledisplay_bl_update_status,
190 };
191
appledisplay_work(struct work_struct * work)192 static void appledisplay_work(struct work_struct *work)
193 {
194 struct appledisplay *pdata =
195 container_of(work, struct appledisplay, work.work);
196 int retval;
197
198 retval = appledisplay_bl_get_brightness(pdata->bd);
199 if (retval >= 0)
200 pdata->bd->props.brightness = retval;
201
202 /* Poll again in about 125ms if there's still a button pressed */
203 if (pdata->button_pressed)
204 schedule_delayed_work(&pdata->work, HZ / 8);
205 }
206
appledisplay_probe(struct usb_interface * iface,const struct usb_device_id * id)207 static int appledisplay_probe(struct usb_interface *iface,
208 const struct usb_device_id *id)
209 {
210 struct backlight_properties props;
211 struct appledisplay *pdata;
212 struct usb_device *udev = interface_to_usbdev(iface);
213 struct usb_endpoint_descriptor *endpoint;
214 int int_in_endpointAddr = 0;
215 int retval, brightness;
216 char bl_name[20];
217
218 /* set up the endpoint information */
219 /* use only the first interrupt-in endpoint */
220 retval = usb_find_int_in_endpoint(iface->cur_altsetting, &endpoint);
221 if (retval) {
222 dev_err(&iface->dev, "Could not find int-in endpoint\n");
223 return retval;
224 }
225
226 int_in_endpointAddr = endpoint->bEndpointAddress;
227
228 /* allocate memory for our device state and initialize it */
229 pdata = kzalloc(sizeof(struct appledisplay), GFP_KERNEL);
230 if (!pdata) {
231 retval = -ENOMEM;
232 goto error;
233 }
234
235 pdata->udev = udev;
236
237 spin_lock_init(&pdata->lock);
238 INIT_DELAYED_WORK(&pdata->work, appledisplay_work);
239 mutex_init(&pdata->sysfslock);
240
241 /* Allocate buffer for control messages */
242 pdata->msgdata = kmalloc(ACD_MSG_BUFFER_LEN, GFP_KERNEL);
243 if (!pdata->msgdata) {
244 retval = -ENOMEM;
245 goto error;
246 }
247
248 /* Allocate interrupt URB */
249 pdata->urb = usb_alloc_urb(0, GFP_KERNEL);
250 if (!pdata->urb) {
251 retval = -ENOMEM;
252 goto error;
253 }
254
255 /* Allocate buffer for interrupt data */
256 pdata->urbdata = usb_alloc_coherent(pdata->udev, ACD_URB_BUFFER_LEN,
257 GFP_KERNEL, &pdata->urb->transfer_dma);
258 if (!pdata->urbdata) {
259 retval = -ENOMEM;
260 dev_err(&iface->dev, "Allocating URB buffer failed\n");
261 goto error;
262 }
263
264 /* Configure interrupt URB */
265 usb_fill_int_urb(pdata->urb, udev,
266 usb_rcvintpipe(udev, int_in_endpointAddr),
267 pdata->urbdata, ACD_URB_BUFFER_LEN, appledisplay_complete,
268 pdata, 1);
269 if (usb_submit_urb(pdata->urb, GFP_KERNEL)) {
270 retval = -EIO;
271 dev_err(&iface->dev, "Submitting URB failed\n");
272 goto error;
273 }
274
275 /* Register backlight device */
276 snprintf(bl_name, sizeof(bl_name), "appledisplay%d",
277 atomic_inc_return(&count_displays) - 1);
278 memset(&props, 0, sizeof(struct backlight_properties));
279 props.type = BACKLIGHT_RAW;
280 props.max_brightness = 0xff;
281 pdata->bd = backlight_device_register(bl_name, NULL, pdata,
282 &appledisplay_bl_data, &props);
283 if (IS_ERR(pdata->bd)) {
284 dev_err(&iface->dev, "Backlight registration failed\n");
285 retval = PTR_ERR(pdata->bd);
286 goto error;
287 }
288
289 /* Try to get brightness */
290 brightness = appledisplay_bl_get_brightness(pdata->bd);
291
292 if (brightness < 0) {
293 retval = brightness;
294 dev_err(&iface->dev,
295 "Error while getting initial brightness: %d\n", retval);
296 goto error;
297 }
298
299 /* Set brightness in backlight device */
300 pdata->bd->props.brightness = brightness;
301
302 /* save our data pointer in the interface device */
303 usb_set_intfdata(iface, pdata);
304
305 printk(KERN_INFO "appledisplay: Apple Cinema Display connected\n");
306
307 return 0;
308
309 error:
310 if (pdata) {
311 if (pdata->urb) {
312 usb_kill_urb(pdata->urb);
313 cancel_delayed_work_sync(&pdata->work);
314 if (pdata->urbdata)
315 usb_free_coherent(pdata->udev, ACD_URB_BUFFER_LEN,
316 pdata->urbdata, pdata->urb->transfer_dma);
317 usb_free_urb(pdata->urb);
318 }
319 if (!IS_ERR(pdata->bd))
320 backlight_device_unregister(pdata->bd);
321 kfree(pdata->msgdata);
322 }
323 usb_set_intfdata(iface, NULL);
324 kfree(pdata);
325 return retval;
326 }
327
appledisplay_disconnect(struct usb_interface * iface)328 static void appledisplay_disconnect(struct usb_interface *iface)
329 {
330 struct appledisplay *pdata = usb_get_intfdata(iface);
331
332 if (pdata) {
333 usb_kill_urb(pdata->urb);
334 cancel_delayed_work_sync(&pdata->work);
335 backlight_device_unregister(pdata->bd);
336 usb_free_coherent(pdata->udev, ACD_URB_BUFFER_LEN,
337 pdata->urbdata, pdata->urb->transfer_dma);
338 usb_free_urb(pdata->urb);
339 kfree(pdata->msgdata);
340 kfree(pdata);
341 }
342
343 printk(KERN_INFO "appledisplay: Apple Cinema Display disconnected\n");
344 }
345
346 static struct usb_driver appledisplay_driver = {
347 .name = "appledisplay",
348 .probe = appledisplay_probe,
349 .disconnect = appledisplay_disconnect,
350 .id_table = appledisplay_table,
351 };
352
appledisplay_init(void)353 static int __init appledisplay_init(void)
354 {
355 return usb_register(&appledisplay_driver);
356 }
357
appledisplay_exit(void)358 static void __exit appledisplay_exit(void)
359 {
360 usb_deregister(&appledisplay_driver);
361 }
362
363 MODULE_AUTHOR("Michael Hanselmann");
364 MODULE_DESCRIPTION("Apple Cinema Display driver");
365 MODULE_LICENSE("GPL");
366
367 module_init(appledisplay_init);
368 module_exit(appledisplay_exit);
369