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(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
  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
 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
 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         brightness = pdata->msgdata[1];
 174         mutex_unlock(&pdata->sysfslock);
 175
 176         if (retval < 0)
 177                 return retval;
 178         else
 179                 return brightness;
 180 }
 181
 182 static const struct backlight_ops appledisplay_bl_data = {
 183         .get_brightness = appledisplay_bl_get_brightness,
 184         .update_status  = appledisplay_bl_update_status,
 185 };
 186
 187 static void appledisplay_work(struct work_struct *work)
 188 {
 189         struct appledisplay *pdata =
 190                 container_of(work, struct appledisplay, work.work);
 191         int retval;
 192
 193         retval = appledisplay_bl_get_brightness(pdata->bd);
 194         if (retval >= 0)
 195                 pdata->bd->props.brightness = retval;
 196
 197         /* Poll again in about 125ms if there's still a button pressed */
 198         if (pdata->button_pressed)
 199                 schedule_delayed_work(&pdata->work, HZ / 8);
 200 }
 201
 202 static int appledisplay_probe(struct usb_interface *iface,
 203         const struct usb_device_id *id)
 204 {
 205         struct backlight_properties props;
 206         struct appledisplay *pdata;
 207         struct usb_device *udev = interface_to_usbdev(iface);
 208         struct usb_endpoint_descriptor *endpoint;
 209         int int_in_endpointAddr = 0;
 210         int retval, brightness;
 211         char bl_name[20];
 212
 213         /* set up the endpoint information */
 214         /* use only the first interrupt-in endpoint */
 215         retval = usb_find_int_in_endpoint(iface->cur_altsetting, &endpoint);
 216         if (retval) {
 217                 dev_err(&iface->dev, "Could not find int-in endpoint\n");
 218                 return retval;
 219         }
 220
 221         int_in_endpointAddr = endpoint->bEndpointAddress;
 222
 223         /* allocate memory for our device state and initialize it */
 224         pdata = kzalloc(sizeof(struct appledisplay), GFP_KERNEL);
 225         if (!pdata) {
 226                 retval = -ENOMEM;
 227                 goto error;
 228         }
 229
 230         pdata->udev = udev;
 231
 232         spin_lock_init(&pdata->lock);
 233         INIT_DELAYED_WORK(&pdata->work, appledisplay_work);
 234         mutex_init(&pdata->sysfslock);
 235
 236         /* Allocate buffer for control messages */
 237         pdata->msgdata = kmalloc(ACD_MSG_BUFFER_LEN, GFP_KERNEL);
 238         if (!pdata->msgdata) {
 239                 retval = -ENOMEM;
 240                 goto error;
 241         }
 242
 243         /* Allocate interrupt URB */
 244         pdata->urb = usb_alloc_urb(0, GFP_KERNEL);
 245         if (!pdata->urb) {
 246                 retval = -ENOMEM;
 247                 goto error;
 248         }
 249
 250         /* Allocate buffer for interrupt data */
 251         pdata->urbdata = usb_alloc_coherent(pdata->udev, ACD_URB_BUFFER_LEN,
 252                 GFP_KERNEL, &pdata->urb->transfer_dma);
 253         if (!pdata->urbdata) {
 254                 retval = -ENOMEM;
 255                 dev_err(&iface->dev, "Allocating URB buffer failed\n");
 256                 goto error;
 257         }
 258
 259         /* Configure interrupt URB */
 260         usb_fill_int_urb(pdata->urb, udev,
 261                 usb_rcvintpipe(udev, int_in_endpointAddr),
 262                 pdata->urbdata, ACD_URB_BUFFER_LEN, appledisplay_complete,
 263                 pdata, 1);
 264         if (usb_submit_urb(pdata->urb, GFP_KERNEL)) {
 265                 retval = -EIO;
 266                 dev_err(&iface->dev, "Submitting URB failed\n");
 267                 goto error;
 268         }
 269
 270         /* Register backlight device */
 271         snprintf(bl_name, sizeof(bl_name), "appledisplay%d",
 272                 atomic_inc_return(&count_displays) - 1);
 273         memset(&props, 0, sizeof(struct backlight_properties));
 274         props.type = BACKLIGHT_RAW;
 275         props.max_brightness = 0xff;
 276         pdata->bd = backlight_device_register(bl_name, NULL, pdata,
 277                                               &appledisplay_bl_data, &props);
 278         if (IS_ERR(pdata->bd)) {
 279                 dev_err(&iface->dev, "Backlight registration failed\n");
 280                 retval = PTR_ERR(pdata->bd);
 281                 goto error;
 282         }
 283
 284         /* Try to get brightness */
 285         brightness = appledisplay_bl_get_brightness(pdata->bd);
 286
 287         if (brightness < 0) {
 288                 retval = brightness;
 289                 dev_err(&iface->dev,
 290                         "Error while getting initial brightness: %d\n", retval);
 291                 goto error;
 292         }
 293
 294         /* Set brightness in backlight device */
 295         pdata->bd->props.brightness = brightness;
 296
 297         /* save our data pointer in the interface device */
 298         usb_set_intfdata(iface, pdata);
 299
 300         printk(KERN_INFO "appledisplay: Apple Cinema Display connected\n");
 301
 302         return 0;
 303
 304 error:
 305         if (pdata) {
 306                 if (pdata->urb) {
 307                         usb_kill_urb(pdata->urb);
 308                         if (pdata->urbdata)
 309                                 usb_free_coherent(pdata->udev, ACD_URB_BUFFER_LEN,
 310                                         pdata->urbdata, pdata->urb->transfer_dma);
 311                         usb_free_urb(pdata->urb);
 312                 }
 313                 if (!IS_ERR(pdata->bd))
 314                         backlight_device_unregister(pdata->bd);
 315                 kfree(pdata->msgdata);
 316         }
 317         usb_set_intfdata(iface, NULL);
 318         kfree(pdata);
 319         return retval;
 320 }
 321
 322 static void appledisplay_disconnect(struct usb_interface *iface)
 323 {
 324         struct appledisplay *pdata = usb_get_intfdata(iface);
 325
 326         if (pdata) {
 327                 usb_kill_urb(pdata->urb);
 328                 cancel_delayed_work_sync(&pdata->work);
 329                 backlight_device_unregister(pdata->bd);
 330                 usb_free_coherent(pdata->udev, ACD_URB_BUFFER_LEN,
 331                         pdata->urbdata, pdata->urb->transfer_dma);
 332                 usb_free_urb(pdata->urb);
 333                 kfree(pdata->msgdata);
 334                 kfree(pdata);
 335         }
 336
 337         printk(KERN_INFO "appledisplay: Apple Cinema Display disconnected\n");
 338 }
 339
 340 static struct usb_driver appledisplay_driver = {
 341         .name           = "appledisplay",
 342         .probe          = appledisplay_probe,
 343         .disconnect     = appledisplay_disconnect,
 344         .id_table       = appledisplay_table,
 345 };
 346
 347 static int __init appledisplay_init(void)
 348 {
 349         return usb_register(&appledisplay_driver);
 350 }
 351
 352 static void __exit appledisplay_exit(void)
 353 {
 354         usb_deregister(&appledisplay_driver);
 355 }
 356
 357 MODULE_AUTHOR("Michael Hanselmann");
 358 MODULE_DESCRIPTION("Apple Cinema Display driver");
 359 MODULE_LICENSE("GPL");
 360
 361 module_init(appledisplay_init);
 362 module_exit(appledisplay_exit);