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 struct mutex sysfslock; /* concurrent read and write */
73 };
74
75 static atomic_t count_displays = ATOMIC_INIT(0);
76
appledisplay_complete(struct urb * urb)77 static void appledisplay_complete(struct urb *urb)
78 {
79 struct appledisplay *pdata = urb->context;
80 struct device *dev = &pdata->udev->dev;
81 int status = urb->status;
82 int retval;
83
84 switch (status) {
85 case 0:
86 /* success */
87 break;
88 case -EOVERFLOW:
89 dev_err(dev,
90 "OVERFLOW with data length %d, actual length is %d\n",
91 ACD_URB_BUFFER_LEN, pdata->urb->actual_length);
92 fallthrough;
93 case -ECONNRESET:
94 case -ENOENT:
95 case -ESHUTDOWN:
96 /* This urb is terminated, clean up */
97 dev_dbg(dev, "%s - urb shuttingdown with status: %d\n",
98 __func__, status);
99 return;
100 default:
101 dev_dbg(dev, "%s - nonzero urb status received: %d\n",
102 __func__, status);
103 goto exit;
104 }
105
106 switch(pdata->urbdata[1]) {
107 case ACD_BTN_BRIGHT_UP:
108 case ACD_BTN_BRIGHT_DOWN:
109 pdata->button_pressed = 1;
110 /*
111 * there is a window during which no device
112 * is registered
113 */
114 if (pdata->bd )
115 schedule_delayed_work(&pdata->work, 0);
116 break;
117 case ACD_BTN_NONE:
118 default:
119 pdata->button_pressed = 0;
120 break;
121 }
122
123 exit:
124 retval = usb_submit_urb(pdata->urb, GFP_ATOMIC);
125 if (retval) {
126 dev_err(dev, "%s - usb_submit_urb failed with result %d\n",
127 __func__, retval);
128 }
129 }
130
appledisplay_bl_update_status(struct backlight_device * bd)131 static int appledisplay_bl_update_status(struct backlight_device *bd)
132 {
133 struct appledisplay *pdata = bl_get_data(bd);
134 int retval;
135
136 mutex_lock(&pdata->sysfslock);
137 pdata->msgdata[0] = 0x10;
138 pdata->msgdata[1] = bd->props.brightness;
139
140 retval = usb_control_msg(
141 pdata->udev,
142 usb_sndctrlpipe(pdata->udev, 0),
143 USB_REQ_SET_REPORT,
144 USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_INTERFACE,
145 ACD_USB_BRIGHTNESS,
146 0,
147 pdata->msgdata, 2,
148 ACD_USB_TIMEOUT);
149 mutex_unlock(&pdata->sysfslock);
150
151 if (retval < 0)
152 return retval;
153 else
154 return 0;
155 }
156
appledisplay_bl_get_brightness(struct backlight_device * bd)157 static int appledisplay_bl_get_brightness(struct backlight_device *bd)
158 {
159 struct appledisplay *pdata = bl_get_data(bd);
160 int retval, brightness;
161
162 mutex_lock(&pdata->sysfslock);
163 retval = usb_control_msg(
164 pdata->udev,
165 usb_rcvctrlpipe(pdata->udev, 0),
166 USB_REQ_GET_REPORT,
167 USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE,
168 ACD_USB_BRIGHTNESS,
169 0,
170 pdata->msgdata, 2,
171 ACD_USB_TIMEOUT);
172 if (retval < 2) {
173 if (retval >= 0)
174 retval = -EMSGSIZE;
175 } else {
176 brightness = pdata->msgdata[1];
177 }
178 mutex_unlock(&pdata->sysfslock);
179
180 if (retval < 0)
181 return retval;
182 else
183 return brightness;
184 }
185
186 static const struct backlight_ops appledisplay_bl_data = {
187 .get_brightness = appledisplay_bl_get_brightness,
188 .update_status = appledisplay_bl_update_status,
189 };
190
appledisplay_work(struct work_struct * work)191 static void appledisplay_work(struct work_struct *work)
192 {
193 struct appledisplay *pdata =
194 container_of(work, struct appledisplay, work.work);
195 int retval;
196
197 retval = appledisplay_bl_get_brightness(pdata->bd);
198 if (retval >= 0)
199 pdata->bd->props.brightness = retval;
200
201 /* Poll again in about 125ms if there's still a button pressed */
202 if (pdata->button_pressed)
203 schedule_delayed_work(&pdata->work, HZ / 8);
204 }
205
appledisplay_probe(struct usb_interface * iface,const struct usb_device_id * id)206 static int appledisplay_probe(struct usb_interface *iface,
207 const struct usb_device_id *id)
208 {
209 struct backlight_properties props;
210 struct backlight_device *backlight;
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 INIT_DELAYED_WORK(&pdata->work, appledisplay_work);
238 mutex_init(&pdata->sysfslock);
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 goto error;
245 }
246
247 /* Allocate interrupt URB */
248 pdata->urb = usb_alloc_urb(0, GFP_KERNEL);
249 if (!pdata->urb) {
250 retval = -ENOMEM;
251 goto error;
252 }
253
254 /* Allocate buffer for interrupt data */
255 pdata->urbdata = usb_alloc_coherent(pdata->udev, ACD_URB_BUFFER_LEN,
256 GFP_KERNEL, &pdata->urb->transfer_dma);
257 if (!pdata->urbdata) {
258 retval = -ENOMEM;
259 dev_err(&iface->dev, "Allocating URB buffer failed\n");
260 goto error;
261 }
262
263 /* Configure interrupt URB */
264 usb_fill_int_urb(pdata->urb, udev,
265 usb_rcvintpipe(udev, int_in_endpointAddr),
266 pdata->urbdata, ACD_URB_BUFFER_LEN, appledisplay_complete,
267 pdata, 1);
268 pdata->urb->transfer_flags = URB_NO_TRANSFER_DMA_MAP;
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 backlight = backlight_device_register(bl_name, NULL, pdata,
282 &appledisplay_bl_data, &props);
283 if (IS_ERR(backlight)) {
284 dev_err(&iface->dev, "Backlight registration failed\n");
285 retval = PTR_ERR(backlight);
286 goto error;
287 }
288 pdata->bd = backlight;
289
290 /* Try to get brightness */
291 brightness = appledisplay_bl_get_brightness(pdata->bd);
292
293 if (brightness < 0) {
294 retval = brightness;
295 dev_err(&iface->dev,
296 "Error while getting initial brightness: %d\n", retval);
297 goto error;
298 }
299
300 /* Set brightness in backlight device */
301 pdata->bd->props.brightness = brightness;
302
303 /* save our data pointer in the interface device */
304 usb_set_intfdata(iface, pdata);
305
306 printk(KERN_INFO "appledisplay: Apple Cinema Display connected\n");
307
308 return 0;
309
310 error:
311 if (pdata) {
312 if (pdata->urb) {
313 usb_kill_urb(pdata->urb);
314 cancel_delayed_work_sync(&pdata->work);
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 module_usb_driver(appledisplay_driver);
353
354 MODULE_AUTHOR("Michael Hanselmann");
355 MODULE_DESCRIPTION("Apple Cinema Display driver");
356 MODULE_LICENSE("GPL");
357