drivers/usb/misc/appledisplay.c

   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(0x9236) },
  55
  56         /* Terminating entry */
  57         { }
  58 };
  59 MODULE_DEVICE_TABLE(usb, appledisplay_table);
  60
  61 /* Structure to hold all of our device specific stuff */
  62 struct appledisplay {
  63         struct usb_device *udev;        /* usb device */
  64         struct urb *urb;                /* usb request block */
  65         struct backlight_device *bd;    /* backlight device */
  66         u8 *urbdata;                    /* interrupt URB data buffer */
  67         u8 *msgdata;                    /* control message data buffer */
  68
  69         struct delayed_work work;
  70         int button_pressed;
  71         spinlock_t lock;
  72         struct mutex sysfslock;         /* concurrent read and write */
  73 };
  74
  75 static atomic_t count_displays = ATOMIC_INIT(0);
  76
  77 static void appledisplay_complete(struct urb *urb)
  78 {
  79         struct appledisplay *pdata = urb->context;
  80         struct device *dev = &pdata->udev->dev;
  81         unsigned long flags;
  82         int status = urb->status;
  83         int retval;
  84
  85         switch (status) {
  86         case 0:
  87                 /* success */
  88                 break;
  89         case -EOVERFLOW:
  90                 dev_err(dev,
  91                         "OVERFLOW with data length %d, actual length is %d\n",
  92                         ACD_URB_BUFFER_LEN, pdata->urb->actual_length);
  93                 /* fall through */
  94         case -ECONNRESET:
  95         case -ENOENT:
  96         case -ESHUTDOWN:
  97                 /* This urb is terminated, clean up */
  98                 dev_dbg(dev, "%s - urb shuttingdown with status: %d\n",
  99                         __func__, status);
 100                 return;
 101         default:
 102                 dev_dbg(dev, "%s - nonzero urb status received: %d\n",
 103                         __func__, status);
 104                 goto exit;
 105         }
 106
 107         spin_lock_irqsave(&pdata->lock, flags);
 108
 109         switch(pdata->urbdata[1]) {
 110         case ACD_BTN_BRIGHT_UP:
 111         case ACD_BTN_BRIGHT_DOWN:
 112                 pdata->button_pressed = 1;
 113                 schedule_delayed_work(&pdata->work, 0);
 114                 break;
 115         case ACD_BTN_NONE:
 116         default:
 117                 pdata->button_pressed = 0;
 118                 break;
 119         }
 120
 121         spin_unlock_irqrestore(&pdata->lock, flags);
 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
 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
 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         brightness = pdata->msgdata[1];
 173         mutex_unlock(&pdata->sysfslock);
 174
 175         if (retval < 0)
 176                 return retval;
 177         else
 178                 return brightness;
 179 }
 180
 181 static const struct backlight_ops appledisplay_bl_data = {
 182         .get_brightness = appledisplay_bl_get_brightness,
 183         .update_status  = appledisplay_bl_update_status,
 184 };
 185
 186 static void appledisplay_work(struct work_struct *work)
 187 {
 188         struct appledisplay *pdata =
 189                 container_of(work, struct appledisplay, work.work);
 190         int retval;
 191
 192         retval = appledisplay_bl_get_brightness(pdata->bd);
 193         if (retval >= 0)
 194                 pdata->bd->props.brightness = retval;
 195
 196         /* Poll again in about 125ms if there's still a button pressed */
 197         if (pdata->button_pressed)
 198                 schedule_delayed_work(&pdata->work, HZ / 8);
 199 }
 200
 201 static int appledisplay_probe(struct usb_interface *iface,
 202         const struct usb_device_id *id)
 203 {
 204         struct backlight_properties props;
 205         struct appledisplay *pdata;
 206         struct usb_device *udev = interface_to_usbdev(iface);
 207         struct usb_endpoint_descriptor *endpoint;
 208         int int_in_endpointAddr = 0;
 209         int retval, brightness;
 210         char bl_name[20];
 211
 212         /* set up the endpoint information */
 213         /* use only the first interrupt-in endpoint */
 214         retval = usb_find_int_in_endpoint(iface->cur_altsetting, &endpoint);
 215         if (retval) {
 216                 dev_err(&iface->dev, "Could not find int-in endpoint\n");
 217                 return retval;
 218         }
 219
 220         int_in_endpointAddr = endpoint->bEndpointAddress;
 221
 222         /* allocate memory for our device state and initialize it */
 223         pdata = kzalloc(sizeof(struct appledisplay), GFP_KERNEL);
 224         if (!pdata) {
 225                 retval = -ENOMEM;
 226                 goto error;
 227         }
 228
 229         pdata->udev = udev;
 230
 231         spin_lock_init(&pdata->lock);
 232         INIT_DELAYED_WORK(&pdata->work, appledisplay_work);
 233         mutex_init(&pdata->sysfslock);
 234
 235         /* Allocate buffer for control messages */
 236         pdata->msgdata = kmalloc(ACD_MSG_BUFFER_LEN, GFP_KERNEL);
 237         if (!pdata->msgdata) {
 238                 retval = -ENOMEM;
 239                 goto error;
 240         }
 241
 242         /* Allocate interrupt URB */
 243         pdata->urb = usb_alloc_urb(0, GFP_KERNEL);
 244         if (!pdata->urb) {
 245                 retval = -ENOMEM;
 246                 goto error;
 247         }
 248
 249         /* Allocate buffer for interrupt data */
 250         pdata->urbdata = usb_alloc_coherent(pdata->udev, ACD_URB_BUFFER_LEN,
 251                 GFP_KERNEL, &pdata->urb->transfer_dma);
 252         if (!pdata->urbdata) {
 253                 retval = -ENOMEM;
 254                 dev_err(&iface->dev, "Allocating URB buffer failed\n");
 255                 goto error;
 256         }
 257
 258         /* Configure interrupt URB */
 259         usb_fill_int_urb(pdata->urb, udev,
 260                 usb_rcvintpipe(udev, int_in_endpointAddr),
 261                 pdata->urbdata, ACD_URB_BUFFER_LEN, appledisplay_complete,
 262                 pdata, 1);
 263         if (usb_submit_urb(pdata->urb, GFP_KERNEL)) {
 264                 retval = -EIO;
 265                 dev_err(&iface->dev, "Submitting URB failed\n");
 266                 goto error;
 267         }
 268
 269         /* Register backlight device */
 270         snprintf(bl_name, sizeof(bl_name), "appledisplay%d",
 271                 atomic_inc_return(&count_displays) - 1);
 272         memset(&props, 0, sizeof(struct backlight_properties));
 273         props.type = BACKLIGHT_RAW;
 274         props.max_brightness = 0xff;
 275         pdata->bd = backlight_device_register(bl_name, NULL, pdata,
 276                                               &appledisplay_bl_data, &props);
 277         if (IS_ERR(pdata->bd)) {
 278                 dev_err(&iface->dev, "Backlight registration failed\n");
 279                 retval = PTR_ERR(pdata->bd);
 280                 goto error;
 281         }
 282
 283         /* Try to get brightness */
 284         brightness = appledisplay_bl_get_brightness(pdata->bd);
 285
 286         if (brightness < 0) {
 287                 retval = brightness;
 288                 dev_err(&iface->dev,
 289                         "Error while getting initial brightness: %d\n", retval);
 290                 goto error;
 291         }
 292
 293         /* Set brightness in backlight device */
 294         pdata->bd->props.brightness = brightness;
 295
 296         /* save our data pointer in the interface device */
 297         usb_set_intfdata(iface, pdata);
 298
 299         printk(KERN_INFO "appledisplay: Apple Cinema Display connected\n");
 300
 301         return 0;
 302
 303 error:
 304         if (pdata) {
 305                 if (pdata->urb) {
 306                         usb_kill_urb(pdata->urb);
 307                         if (pdata->urbdata)
 308                                 usb_free_coherent(pdata->udev, ACD_URB_BUFFER_LEN,
 309                                         pdata->urbdata, pdata->urb->transfer_dma);
 310                         usb_free_urb(pdata->urb);
 311                 }
 312                 if (!IS_ERR(pdata->bd))
 313                         backlight_device_unregister(pdata->bd);
 314                 kfree(pdata->msgdata);
 315         }
 316         usb_set_intfdata(iface, NULL);
 317         kfree(pdata);
 318         return retval;
 319 }
 320
 321 static void appledisplay_disconnect(struct usb_interface *iface)
 322 {
 323         struct appledisplay *pdata = usb_get_intfdata(iface);
 324
 325         if (pdata) {
 326                 usb_kill_urb(pdata->urb);
 327                 cancel_delayed_work_sync(&pdata->work);
 328                 backlight_device_unregister(pdata->bd);
 329                 usb_free_coherent(pdata->udev, ACD_URB_BUFFER_LEN,
 330                         pdata->urbdata, pdata->urb->transfer_dma);
 331                 usb_free_urb(pdata->urb);
 332                 kfree(pdata->msgdata);
 333                 kfree(pdata);
 334         }
 335
 336         printk(KERN_INFO "appledisplay: Apple Cinema Display disconnected\n");
 337 }
 338
 339 static struct usb_driver appledisplay_driver = {
 340         .name           = "appledisplay",
 341         .probe          = appledisplay_probe,
 342         .disconnect     = appledisplay_disconnect,
 343         .id_table       = appledisplay_table,
 344 };
 345
 346 static int __init appledisplay_init(void)
 347 {
 348         return usb_register(&appledisplay_driver);
 349 }
 350
 351 static void __exit appledisplay_exit(void)
 352 {
 353         usb_deregister(&appledisplay_driver);
 354 }
 355
 356 MODULE_AUTHOR("Michael Hanselmann");
 357 MODULE_DESCRIPTION("Apple Cinema Display driver");
 358 MODULE_LICENSE("GPL");
 359
 360 module_init(appledisplay_init);
 361 module_exit(appledisplay_exit);