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         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         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
 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         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
 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
 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
 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");