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 * This program is free software; you can redistribute it and/or modify 10 * it under the terms of the GNU General Public License as published by 11 * the Free Software Foundation; either version 2 of the License, or 12 * (at your option) any later version. 13 * 14 * This program is distributed in the hope that it will be useful, 15 * but WITHOUT ANY WARRANTY; without even the implied warranty of 16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 17 * GNU General Public License for more details. 18 * 19 * You should have received a copy of the GNU General Public License 20 * along with this program; if not, write to the Free Software 21 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. 22 */ 23 24 #include <linux/kernel.h> 25 #include <linux/errno.h> 26 #include <linux/init.h> 27 #include <linux/module.h> 28 #include <linux/slab.h> 29 #include <linux/usb.h> 30 #include <linux/backlight.h> 31 #include <linux/timer.h> 32 #include <linux/workqueue.h> 33 #include <linux/atomic.h> 34 35 #define APPLE_VENDOR_ID 0x05AC 36 37 #define USB_REQ_GET_REPORT 0x01 38 #define USB_REQ_SET_REPORT 0x09 39 40 #define ACD_USB_TIMEOUT 250 41 42 #define ACD_USB_EDID 0x0302 43 #define ACD_USB_BRIGHTNESS 0x0310 44 45 #define ACD_BTN_NONE 0 46 #define ACD_BTN_BRIGHT_UP 3 47 #define ACD_BTN_BRIGHT_DOWN 4 48 49 #define ACD_URB_BUFFER_LEN 2 50 #define ACD_MSG_BUFFER_LEN 2 51 52 #define APPLEDISPLAY_DEVICE(prod) \ 53 .match_flags = USB_DEVICE_ID_MATCH_DEVICE | \ 54 USB_DEVICE_ID_MATCH_INT_CLASS | \ 55 USB_DEVICE_ID_MATCH_INT_PROTOCOL, \ 56 .idVendor = APPLE_VENDOR_ID, \ 57 .idProduct = (prod), \ 58 .bInterfaceClass = USB_CLASS_HID, \ 59 .bInterfaceProtocol = 0x00 60 61 /* table of devices that work with this driver */ 62 static const struct usb_device_id appledisplay_table[] = { 63 { APPLEDISPLAY_DEVICE(0x9218) }, 64 { APPLEDISPLAY_DEVICE(0x9219) }, 65 { APPLEDISPLAY_DEVICE(0x921c) }, 66 { APPLEDISPLAY_DEVICE(0x921d) }, 67 { APPLEDISPLAY_DEVICE(0x9236) }, 68 69 /* Terminating entry */ 70 { } 71 }; 72 MODULE_DEVICE_TABLE(usb, appledisplay_table); 73 74 /* Structure to hold all of our device specific stuff */ 75 struct appledisplay { 76 struct usb_device *udev; /* usb device */ 77 struct urb *urb; /* usb request block */ 78 struct backlight_device *bd; /* backlight device */ 79 u8 *urbdata; /* interrupt URB data buffer */ 80 u8 *msgdata; /* control message data buffer */ 81 82 struct delayed_work work; 83 int button_pressed; 84 spinlock_t lock; 85 struct mutex sysfslock; /* concurrent read and write */ 86 }; 87 88 static atomic_t count_displays = ATOMIC_INIT(0); 89 90 static 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 schedule_delayed_work(&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); 134 135 exit: 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 } 142 143 static 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 } 165 166 static 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 } 189 190 static const struct backlight_ops appledisplay_bl_data = { 191 .get_brightness = appledisplay_bl_get_brightness, 192 .update_status = appledisplay_bl_update_status, 193 }; 194 195 static 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 } 209 210 static 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_endpoint_descriptor *endpoint; 217 int int_in_endpointAddr = 0; 218 int retval, brightness; 219 char bl_name[20]; 220 221 /* set up the endpoint information */ 222 /* use only the first interrupt-in endpoint */ 223 retval = usb_find_int_in_endpoint(iface->cur_altsetting, &endpoint); 224 if (retval) { 225 dev_err(&iface->dev, "Could not find int-in endpoint\n"); 226 return retval; 227 } 228 229 int_in_endpointAddr = endpoint->bEndpointAddress; 230 231 /* allocate memory for our device state and initialize it */ 232 pdata = kzalloc(sizeof(struct appledisplay), GFP_KERNEL); 233 if (!pdata) { 234 retval = -ENOMEM; 235 goto error; 236 } 237 238 pdata->udev = udev; 239 240 spin_lock_init(&pdata->lock); 241 INIT_DELAYED_WORK(&pdata->work, appledisplay_work); 242 mutex_init(&pdata->sysfslock); 243 244 /* Allocate buffer for control messages */ 245 pdata->msgdata = kmalloc(ACD_MSG_BUFFER_LEN, GFP_KERNEL); 246 if (!pdata->msgdata) { 247 retval = -ENOMEM; 248 goto error; 249 } 250 251 /* Allocate interrupt URB */ 252 pdata->urb = usb_alloc_urb(0, GFP_KERNEL); 253 if (!pdata->urb) { 254 retval = -ENOMEM; 255 goto error; 256 } 257 258 /* Allocate buffer for interrupt data */ 259 pdata->urbdata = usb_alloc_coherent(pdata->udev, ACD_URB_BUFFER_LEN, 260 GFP_KERNEL, &pdata->urb->transfer_dma); 261 if (!pdata->urbdata) { 262 retval = -ENOMEM; 263 dev_err(&iface->dev, "Allocating URB buffer failed\n"); 264 goto error; 265 } 266 267 /* Configure interrupt URB */ 268 usb_fill_int_urb(pdata->urb, udev, 269 usb_rcvintpipe(udev, int_in_endpointAddr), 270 pdata->urbdata, ACD_URB_BUFFER_LEN, appledisplay_complete, 271 pdata, 1); 272 if (usb_submit_urb(pdata->urb, GFP_KERNEL)) { 273 retval = -EIO; 274 dev_err(&iface->dev, "Submitting URB failed\n"); 275 goto error; 276 } 277 278 /* Register backlight device */ 279 snprintf(bl_name, sizeof(bl_name), "appledisplay%d", 280 atomic_inc_return(&count_displays) - 1); 281 memset(&props, 0, sizeof(struct backlight_properties)); 282 props.type = BACKLIGHT_RAW; 283 props.max_brightness = 0xff; 284 pdata->bd = backlight_device_register(bl_name, NULL, pdata, 285 &appledisplay_bl_data, &props); 286 if (IS_ERR(pdata->bd)) { 287 dev_err(&iface->dev, "Backlight registration failed\n"); 288 retval = PTR_ERR(pdata->bd); 289 goto error; 290 } 291 292 /* Try to get brightness */ 293 brightness = appledisplay_bl_get_brightness(pdata->bd); 294 295 if (brightness < 0) { 296 retval = brightness; 297 dev_err(&iface->dev, 298 "Error while getting initial brightness: %d\n", retval); 299 goto error; 300 } 301 302 /* Set brightness in backlight device */ 303 pdata->bd->props.brightness = brightness; 304 305 /* save our data pointer in the interface device */ 306 usb_set_intfdata(iface, pdata); 307 308 printk(KERN_INFO "appledisplay: Apple Cinema Display connected\n"); 309 310 return 0; 311 312 error: 313 if (pdata) { 314 if (pdata->urb) { 315 usb_kill_urb(pdata->urb); 316 if (pdata->urbdata) 317 usb_free_coherent(pdata->udev, ACD_URB_BUFFER_LEN, 318 pdata->urbdata, pdata->urb->transfer_dma); 319 usb_free_urb(pdata->urb); 320 } 321 if (!IS_ERR(pdata->bd)) 322 backlight_device_unregister(pdata->bd); 323 kfree(pdata->msgdata); 324 } 325 usb_set_intfdata(iface, NULL); 326 kfree(pdata); 327 return retval; 328 } 329 330 static void appledisplay_disconnect(struct usb_interface *iface) 331 { 332 struct appledisplay *pdata = usb_get_intfdata(iface); 333 334 if (pdata) { 335 usb_kill_urb(pdata->urb); 336 cancel_delayed_work_sync(&pdata->work); 337 backlight_device_unregister(pdata->bd); 338 usb_free_coherent(pdata->udev, ACD_URB_BUFFER_LEN, 339 pdata->urbdata, pdata->urb->transfer_dma); 340 usb_free_urb(pdata->urb); 341 kfree(pdata->msgdata); 342 kfree(pdata); 343 } 344 345 printk(KERN_INFO "appledisplay: Apple Cinema Display disconnected\n"); 346 } 347 348 static struct usb_driver appledisplay_driver = { 349 .name = "appledisplay", 350 .probe = appledisplay_probe, 351 .disconnect = appledisplay_disconnect, 352 .id_table = appledisplay_table, 353 }; 354 355 static int __init appledisplay_init(void) 356 { 357 return usb_register(&appledisplay_driver); 358 } 359 360 static void __exit appledisplay_exit(void) 361 { 362 usb_deregister(&appledisplay_driver); 363 } 364 365 MODULE_AUTHOR("Michael Hanselmann"); 366 MODULE_DESCRIPTION("Apple Cinema Display driver"); 367 MODULE_LICENSE("GPL"); 368 369 module_init(appledisplay_init); 370 module_exit(appledisplay_exit); 371