drivers/hid/i2c-hid/i2c-hid.c

   1 /*
   2  * HID over I2C protocol implementation
   3  *
   4  * Copyright (c) 2012 Benjamin Tissoires <benjamin.tissoires@gmail.com>
   5  * Copyright (c) 2012 Ecole Nationale de l'Aviation Civile, France
   6  * Copyright (c) 2012 Red Hat, Inc
   7  *
   8  * This code is partly based on "USB HID support for Linux":
   9  *
  10  *  Copyright (c) 1999 Andreas Gal
  11  *  Copyright (c) 2000-2005 Vojtech Pavlik <vojtech@suse.cz>
  12  *  Copyright (c) 2005 Michael Haboustak <mike-@cinci.rr.com> for Concept2, Inc
  13  *  Copyright (c) 2007-2008 Oliver Neukum
  14  *  Copyright (c) 2006-2010 Jiri Kosina
  15  *
  16  * This file is subject to the terms and conditions of the GNU General Public
  17  * License.  See the file COPYING in the main directory of this archive for
  18  * more details.
  19  */
  20
  21 #include <linux/module.h>
  22 #include <linux/i2c.h>
  23 #include <linux/interrupt.h>
  24 #include <linux/input.h>
  25 #include <linux/delay.h>
  26 #include <linux/slab.h>
  27 #include <linux/pm.h>
  28 #include <linux/device.h>
  29 #include <linux/wait.h>
  30 #include <linux/err.h>
  31 #include <linux/string.h>
  32 #include <linux/list.h>
  33 #include <linux/jiffies.h>
  34 #include <linux/kernel.h>
  35 #include <linux/hid.h>
  36 #include <linux/mutex.h>
  37
  38 #include <linux/i2c/i2c-hid.h>
  39
  40 /* flags */
  41 #define I2C_HID_STARTED         (1 << 0)
  42 #define I2C_HID_RESET_PENDING   (1 << 1)
  43 #define I2C_HID_READ_PENDING    (1 << 2)
  44
  45 #define I2C_HID_PWR_ON          0x00
  46 #define I2C_HID_PWR_SLEEP       0x01
  47
  48 /* debug option */
  49 static bool debug;
  50 module_param(debug, bool, 0444);
  51 MODULE_PARM_DESC(debug, "print a lot of debug information");
  52
  53 #define i2c_hid_dbg(ihid, fmt, arg...)                                    \
  54 do {                                                                      \
  55         if (debug)                                                        \
  56                 dev_printk(KERN_DEBUG, &(ihid)->client->dev, fmt, ##arg); \
  57 } while (0)
  58
  59 struct i2c_hid_desc {
  60         __le16 wHIDDescLength;
  61         __le16 bcdVersion;
  62         __le16 wReportDescLength;
  63         __le16 wReportDescRegister;
  64         __le16 wInputRegister;
  65         __le16 wMaxInputLength;
  66         __le16 wOutputRegister;
  67         __le16 wMaxOutputLength;
  68         __le16 wCommandRegister;
  69         __le16 wDataRegister;
  70         __le16 wVendorID;
  71         __le16 wProductID;
  72         __le16 wVersionID;
  73         __le32 reserved;
  74 } __packed;
  75
  76 struct i2c_hid_cmd {
  77         unsigned int registerIndex;
  78         __u8 opcode;
  79         unsigned int length;
  80         bool wait;
  81 };
  82
  83 union command {
  84         u8 data[0];
  85         struct cmd {
  86                 __le16 reg;
  87                 __u8 reportTypeID;
  88                 __u8 opcode;
  89         } __packed c;
  90 };
  91
  92 #define I2C_HID_CMD(opcode_) \
  93         .opcode = opcode_, .length = 4, \
  94         .registerIndex = offsetof(struct i2c_hid_desc, wCommandRegister)
  95
  96 /* fetch HID descriptor */
  97 static const struct i2c_hid_cmd hid_descr_cmd = { .length = 2 };
  98 /* fetch report descriptors */
  99 static const struct i2c_hid_cmd hid_report_descr_cmd = {
 100                 .registerIndex = offsetof(struct i2c_hid_desc,
 101                         wReportDescRegister),
 102                 .opcode = 0x00,
 103                 .length = 2 };
 104 /* commands */
 105 static const struct i2c_hid_cmd hid_reset_cmd =         { I2C_HID_CMD(0x01),
 106                                                           .wait = true };
 107 static const struct i2c_hid_cmd hid_get_report_cmd =    { I2C_HID_CMD(0x02) };
 108 static const struct i2c_hid_cmd hid_set_report_cmd =    { I2C_HID_CMD(0x03) };
 109 static const struct i2c_hid_cmd hid_set_power_cmd =     { I2C_HID_CMD(0x08) };
 110
 111 /*
 112  * These definitions are not used here, but are defined by the spec.
 113  * Keeping them here for documentation purposes.
 114  *
 115  * static const struct i2c_hid_cmd hid_get_idle_cmd = { I2C_HID_CMD(0x04) };
 116  * static const struct i2c_hid_cmd hid_set_idle_cmd = { I2C_HID_CMD(0x05) };
 117  * static const struct i2c_hid_cmd hid_get_protocol_cmd = { I2C_HID_CMD(0x06) };
 118  * static const struct i2c_hid_cmd hid_set_protocol_cmd = { I2C_HID_CMD(0x07) };
 119  */
 120
 121 static DEFINE_MUTEX(i2c_hid_open_mut);
 122
 123 /* The main device structure */
 124 struct i2c_hid {
 125         struct i2c_client       *client;        /* i2c client */
 126         struct hid_device       *hid;   /* pointer to corresponding HID dev */
 127         union {
 128                 __u8 hdesc_buffer[sizeof(struct i2c_hid_desc)];
 129                 struct i2c_hid_desc hdesc;      /* the HID Descriptor */
 130         };
 131         __le16                  wHIDDescRegister; /* location of the i2c
 132                                                    * register of the HID
 133                                                    * descriptor. */
 134         unsigned int            bufsize;        /* i2c buffer size */
 135         char                    *inbuf;         /* Input buffer */
 136         char                    *cmdbuf;        /* Command buffer */
 137         char                    *argsbuf;       /* Command arguments buffer */
 138
 139         unsigned long           flags;          /* device flags */
 140
 141         wait_queue_head_t       wait;           /* For waiting the interrupt */
 142 };
 143
 144 static int __i2c_hid_command(struct i2c_client *client,
 145                 const struct i2c_hid_cmd *command, u8 reportID,
 146                 u8 reportType, u8 *args, int args_len,
 147                 unsigned char *buf_recv, int data_len)
 148 {
 149         struct i2c_hid *ihid = i2c_get_clientdata(client);
 150         union command *cmd = (union command *)ihid->cmdbuf;
 151         int ret;
 152         struct i2c_msg msg[2];
 153         int msg_num = 1;
 154
 155         int length = command->length;
 156         bool wait = command->wait;
 157         unsigned int registerIndex = command->registerIndex;
 158
 159         /* special case for hid_descr_cmd */
 160         if (command == &hid_descr_cmd) {
 161                 cmd->c.reg = ihid->wHIDDescRegister;
 162         } else {
 163                 cmd->data[0] = ihid->hdesc_buffer[registerIndex];
 164                 cmd->data[1] = ihid->hdesc_buffer[registerIndex + 1];
 165         }
 166
 167         if (length > 2) {
 168                 cmd->c.opcode = command->opcode;
 169                 cmd->c.reportTypeID = reportID | reportType << 4;
 170         }
 171
 172         memcpy(cmd->data + length, args, args_len);
 173         length += args_len;
 174
 175         i2c_hid_dbg(ihid, "%s: cmd=%*ph\n", __func__, length, cmd->data);
 176
 177         msg[0].addr = client->addr;
 178         msg[0].flags = client->flags & I2C_M_TEN;
 179         msg[0].len = length;
 180         msg[0].buf = cmd->data;
 181         if (data_len > 0) {
 182                 msg[1].addr = client->addr;
 183                 msg[1].flags = client->flags & I2C_M_TEN;
 184                 msg[1].flags |= I2C_M_RD;
 185                 msg[1].len = data_len;
 186                 msg[1].buf = buf_recv;
 187                 msg_num = 2;
 188                 set_bit(I2C_HID_READ_PENDING, &ihid->flags);
 189         }
 190
 191         if (wait)
 192                 set_bit(I2C_HID_RESET_PENDING, &ihid->flags);
 193
 194         ret = i2c_transfer(client->adapter, msg, msg_num);
 195
 196         if (data_len > 0)
 197                 clear_bit(I2C_HID_READ_PENDING, &ihid->flags);
 198
 199         if (ret != msg_num)
 200                 return ret < 0 ? ret : -EIO;
 201
 202         ret = 0;
 203
 204         if (wait) {
 205                 i2c_hid_dbg(ihid, "%s: waiting...\n", __func__);
 206                 if (!wait_event_timeout(ihid->wait,
 207                                 !test_bit(I2C_HID_RESET_PENDING, &ihid->flags),
 208                                 msecs_to_jiffies(5000)))
 209                         ret = -ENODATA;
 210                 i2c_hid_dbg(ihid, "%s: finished.\n", __func__);
 211         }
 212
 213         return ret;
 214 }
 215
 216 static int i2c_hid_command(struct i2c_client *client,
 217                 const struct i2c_hid_cmd *command,
 218                 unsigned char *buf_recv, int data_len)
 219 {
 220         return __i2c_hid_command(client, command, 0, 0, NULL, 0,
 221                                 buf_recv, data_len);
 222 }
 223
 224 static int i2c_hid_get_report(struct i2c_client *client, u8 reportType,
 225                 u8 reportID, unsigned char *buf_recv, int data_len)
 226 {
 227         struct i2c_hid *ihid = i2c_get_clientdata(client);
 228         u8 args[3];
 229         int ret;
 230         int args_len = 0;
 231         u16 readRegister = le16_to_cpu(ihid->hdesc.wDataRegister);
 232
 233         i2c_hid_dbg(ihid, "%s\n", __func__);
 234
 235         if (reportID >= 0x0F) {
 236                 args[args_len++] = reportID;
 237                 reportID = 0x0F;
 238         }
 239
 240         args[args_len++] = readRegister & 0xFF;
 241         args[args_len++] = readRegister >> 8;
 242
 243         ret = __i2c_hid_command(client, &hid_get_report_cmd, reportID,
 244                 reportType, args, args_len, buf_recv, data_len);
 245         if (ret) {
 246                 dev_err(&client->dev,
 247                         "failed to retrieve report from device.\n");
 248                 return ret;
 249         }
 250
 251         return 0;
 252 }
 253
 254 static int i2c_hid_set_report(struct i2c_client *client, u8 reportType,
 255                 u8 reportID, unsigned char *buf, size_t data_len)
 256 {
 257         struct i2c_hid *ihid = i2c_get_clientdata(client);
 258         u8 *args = ihid->argsbuf;
 259         int ret;
 260         u16 dataRegister = le16_to_cpu(ihid->hdesc.wDataRegister);
 261
 262         /* hidraw already checked that data_len < HID_MAX_BUFFER_SIZE */
 263         u16 size =      2                       /* size */ +
 264                         (reportID ? 1 : 0)      /* reportID */ +
 265                         data_len                /* buf */;
 266         int args_len =  (reportID >= 0x0F ? 1 : 0) /* optional third byte */ +
 267                         2                       /* dataRegister */ +
 268                         size                    /* args */;
 269         int index = 0;
 270
 271         i2c_hid_dbg(ihid, "%s\n", __func__);
 272
 273         if (reportID >= 0x0F) {
 274                 args[index++] = reportID;
 275                 reportID = 0x0F;
 276         }
 277
 278         args[index++] = dataRegister & 0xFF;
 279         args[index++] = dataRegister >> 8;
 280
 281         args[index++] = size & 0xFF;
 282         args[index++] = size >> 8;
 283
 284         if (reportID)
 285                 args[index++] = reportID;
 286
 287         memcpy(&args[index], buf, data_len);
 288
 289         ret = __i2c_hid_command(client, &hid_set_report_cmd, reportID,
 290                 reportType, args, args_len, NULL, 0);
 291         if (ret) {
 292                 dev_err(&client->dev, "failed to set a report to device.\n");
 293                 return ret;
 294         }
 295
 296         return data_len;
 297 }
 298
 299 static int i2c_hid_set_power(struct i2c_client *client, int power_state)
 300 {
 301         struct i2c_hid *ihid = i2c_get_clientdata(client);
 302         int ret;
 303
 304         i2c_hid_dbg(ihid, "%s\n", __func__);
 305
 306         ret = __i2c_hid_command(client, &hid_set_power_cmd, power_state,
 307                 0, NULL, 0, NULL, 0);
 308         if (ret)
 309                 dev_err(&client->dev, "failed to change power setting.\n");
 310
 311         return ret;
 312 }
 313
 314 static int i2c_hid_hwreset(struct i2c_client *client)
 315 {
 316         struct i2c_hid *ihid = i2c_get_clientdata(client);
 317         int ret;
 318
 319         i2c_hid_dbg(ihid, "%s\n", __func__);
 320
 321         ret = i2c_hid_set_power(client, I2C_HID_PWR_ON);
 322         if (ret)
 323                 return ret;
 324
 325         i2c_hid_dbg(ihid, "resetting...\n");
 326
 327         ret = i2c_hid_command(client, &hid_reset_cmd, NULL, 0);
 328         if (ret) {
 329                 dev_err(&client->dev, "failed to reset device.\n");
 330                 i2c_hid_set_power(client, I2C_HID_PWR_SLEEP);
 331                 return ret;
 332         }
 333
 334         return 0;
 335 }
 336
 337 static void i2c_hid_get_input(struct i2c_hid *ihid)
 338 {
 339         int ret, ret_size;
 340         int size = le16_to_cpu(ihid->hdesc.wMaxInputLength);
 341
 342         ret = i2c_master_recv(ihid->client, ihid->inbuf, size);
 343         if (ret != size) {
 344                 if (ret < 0)
 345                         return;
 346
 347                 dev_err(&ihid->client->dev, "%s: got %d data instead of %d\n",
 348                         __func__, ret, size);
 349                 return;
 350         }
 351
 352         ret_size = ihid->inbuf[0] | ihid->inbuf[1] << 8;
 353
 354         if (!ret_size) {
 355                 /* host or device initiated RESET completed */
 356                 if (test_and_clear_bit(I2C_HID_RESET_PENDING, &ihid->flags))
 357                         wake_up(&ihid->wait);
 358                 return;
 359         }
 360
 361         if (ret_size > size) {
 362                 dev_err(&ihid->client->dev, "%s: incomplete report (%d/%d)\n",
 363                         __func__, size, ret_size);
 364                 return;
 365         }
 366
 367         i2c_hid_dbg(ihid, "input: %*ph\n", ret_size, ihid->inbuf);
 368
 369         if (test_bit(I2C_HID_STARTED, &ihid->flags))
 370                 hid_input_report(ihid->hid, HID_INPUT_REPORT, ihid->inbuf + 2,
 371                                 ret_size - 2, 1);
 372
 373         return;
 374 }
 375
 376 static irqreturn_t i2c_hid_irq(int irq, void *dev_id)
 377 {
 378         struct i2c_hid *ihid = dev_id;
 379
 380         if (test_bit(I2C_HID_READ_PENDING, &ihid->flags))
 381                 return IRQ_HANDLED;
 382
 383         i2c_hid_get_input(ihid);
 384
 385         return IRQ_HANDLED;
 386 }
 387
 388 static int i2c_hid_get_report_length(struct hid_report *report)
 389 {
 390         return ((report->size - 1) >> 3) + 1 +
 391                 report->device->report_enum[report->type].numbered + 2;
 392 }
 393
 394 static void i2c_hid_init_report(struct hid_report *report, u8 *buffer,
 395         size_t bufsize)
 396 {
 397         struct hid_device *hid = report->device;
 398         struct i2c_client *client = hid->driver_data;
 399         struct i2c_hid *ihid = i2c_get_clientdata(client);
 400         unsigned int size, ret_size;
 401
 402         size = i2c_hid_get_report_length(report);
 403         if (i2c_hid_get_report(client,
 404                         report->type == HID_FEATURE_REPORT ? 0x03 : 0x01,
 405                         report->id, buffer, size))
 406                 return;
 407
 408         i2c_hid_dbg(ihid, "report (len=%d): %*ph\n", size, size, ihid->inbuf);
 409
 410         ret_size = buffer[0] | (buffer[1] << 8);
 411
 412         if (ret_size != size) {
 413                 dev_err(&client->dev, "error in %s size:%d / ret_size:%d\n",
 414                         __func__, size, ret_size);
 415                 return;
 416         }
 417
 418         /* hid->driver_lock is held as we are in probe function,
 419          * we just need to setup the input fields, so using
 420          * hid_report_raw_event is safe. */
 421         hid_report_raw_event(hid, report->type, buffer + 2, size - 2, 1);
 422 }
 423
 424 /*
 425  * Initialize all reports
 426  */
 427 static void i2c_hid_init_reports(struct hid_device *hid)
 428 {
 429         struct hid_report *report;
 430         struct i2c_client *client = hid->driver_data;
 431         struct i2c_hid *ihid = i2c_get_clientdata(client);
 432         u8 *inbuf = kzalloc(ihid->bufsize, GFP_KERNEL);
 433
 434         if (!inbuf) {
 435                 dev_err(&client->dev, "can not retrieve initial reports\n");
 436                 return;
 437         }
 438
 439         list_for_each_entry(report,
 440                 &hid->report_enum[HID_INPUT_REPORT].report_list, list)
 441                 i2c_hid_init_report(report, inbuf, ihid->bufsize);
 442
 443         list_for_each_entry(report,
 444                 &hid->report_enum[HID_FEATURE_REPORT].report_list, list)
 445                 i2c_hid_init_report(report, inbuf, ihid->bufsize);
 446
 447         kfree(inbuf);
 448 }
 449
 450 /*
 451  * Traverse the supplied list of reports and find the longest
 452  */
 453 static void i2c_hid_find_max_report(struct hid_device *hid, unsigned int type,
 454                 unsigned int *max)
 455 {
 456         struct hid_report *report;
 457         unsigned int size;
 458
 459         /* We should not rely on wMaxInputLength, as some devices may set it to
 460          * a wrong length. */
 461         list_for_each_entry(report, &hid->report_enum[type].report_list, list) {
 462                 size = i2c_hid_get_report_length(report);
 463                 if (*max < size)
 464                         *max = size;
 465         }
 466 }
 467
 468 static void i2c_hid_free_buffers(struct i2c_hid *ihid)
 469 {
 470         kfree(ihid->inbuf);
 471         kfree(ihid->argsbuf);
 472         kfree(ihid->cmdbuf);
 473         ihid->inbuf = NULL;
 474         ihid->cmdbuf = NULL;
 475         ihid->argsbuf = NULL;
 476         ihid->bufsize = 0;
 477 }
 478
 479 static int i2c_hid_alloc_buffers(struct i2c_hid *ihid, size_t report_size)
 480 {
 481         /* the worst case is computed from the set_report command with a
 482          * reportID > 15 and the maximum report length */
 483         int args_len = sizeof(__u8) + /* optional ReportID byte */
 484                        sizeof(__u16) + /* data register */
 485                        sizeof(__u16) + /* size of the report */
 486                        report_size; /* report */
 487
 488         ihid->inbuf = kzalloc(report_size, GFP_KERNEL);
 489         ihid->argsbuf = kzalloc(args_len, GFP_KERNEL);
 490         ihid->cmdbuf = kzalloc(sizeof(union command) + args_len, GFP_KERNEL);
 491
 492         if (!ihid->inbuf || !ihid->argsbuf || !ihid->cmdbuf) {
 493                 i2c_hid_free_buffers(ihid);
 494                 return -ENOMEM;
 495         }
 496
 497         ihid->bufsize = report_size;
 498
 499         return 0;
 500 }
 501
 502 static int i2c_hid_get_raw_report(struct hid_device *hid,
 503                 unsigned char report_number, __u8 *buf, size_t count,
 504                 unsigned char report_type)
 505 {
 506         struct i2c_client *client = hid->driver_data;
 507         struct i2c_hid *ihid = i2c_get_clientdata(client);
 508         size_t ret_count, ask_count;
 509         int ret;
 510
 511         if (report_type == HID_OUTPUT_REPORT)
 512                 return -EINVAL;
 513
 514         /* +2 bytes to include the size of the reply in the query buffer */
 515         ask_count = min(count + 2, (size_t)ihid->bufsize);
 516
 517         ret = i2c_hid_get_report(client,
 518                         report_type == HID_FEATURE_REPORT ? 0x03 : 0x01,
 519                         report_number, ihid->inbuf, ask_count);
 520
 521         if (ret < 0)
 522                 return ret;
 523
 524         ret_count = ihid->inbuf[0] | (ihid->inbuf[1] << 8);
 525
 526         if (ret_count <= 2)
 527                 return 0;
 528
 529         ret_count = min(ret_count, ask_count);
 530
 531         /* The query buffer contains the size, dropping it in the reply */
 532         count = min(count, ret_count - 2);
 533         memcpy(buf, ihid->inbuf + 2, count);
 534
 535         return count;
 536 }
 537
 538 static int i2c_hid_output_raw_report(struct hid_device *hid, __u8 *buf,
 539                 size_t count, unsigned char report_type)
 540 {
 541         struct i2c_client *client = hid->driver_data;
 542         int report_id = buf[0];
 543
 544         if (report_type == HID_INPUT_REPORT)
 545                 return -EINVAL;
 546
 547         return i2c_hid_set_report(client,
 548                                 report_type == HID_FEATURE_REPORT ? 0x03 : 0x02,
 549                                 report_id, buf, count);
 550 }
 551
 552 static int i2c_hid_parse(struct hid_device *hid)
 553 {
 554         struct i2c_client *client = hid->driver_data;
 555         struct i2c_hid *ihid = i2c_get_clientdata(client);
 556         struct i2c_hid_desc *hdesc = &ihid->hdesc;
 557         unsigned int rsize;
 558         char *rdesc;
 559         int ret;
 560         int tries = 3;
 561
 562         i2c_hid_dbg(ihid, "entering %s\n", __func__);
 563
 564         rsize = le16_to_cpu(hdesc->wReportDescLength);
 565         if (!rsize || rsize > HID_MAX_DESCRIPTOR_SIZE) {
 566                 dbg_hid("weird size of report descriptor (%u)\n", rsize);
 567                 return -EINVAL;
 568         }
 569
 570         do {
 571                 ret = i2c_hid_hwreset(client);
 572                 if (ret)
 573                         msleep(1000);
 574         } while (tries-- > 0 && ret);
 575
 576         if (ret)
 577                 return ret;
 578
 579         rdesc = kzalloc(rsize, GFP_KERNEL);
 580
 581         if (!rdesc) {
 582                 dbg_hid("couldn't allocate rdesc memory\n");
 583                 return -ENOMEM;
 584         }
 585
 586         i2c_hid_dbg(ihid, "asking HID report descriptor\n");
 587
 588         ret = i2c_hid_command(client, &hid_report_descr_cmd, rdesc, rsize);
 589         if (ret) {
 590                 hid_err(hid, "reading report descriptor failed\n");
 591                 kfree(rdesc);
 592                 return -EIO;
 593         }
 594
 595         i2c_hid_dbg(ihid, "Report Descriptor: %*ph\n", rsize, rdesc);
 596
 597         ret = hid_parse_report(hid, rdesc, rsize);
 598         kfree(rdesc);
 599         if (ret) {
 600                 dbg_hid("parsing report descriptor failed\n");
 601                 return ret;
 602         }
 603
 604         return 0;
 605 }
 606
 607 static int i2c_hid_start(struct hid_device *hid)
 608 {
 609         struct i2c_client *client = hid->driver_data;
 610         struct i2c_hid *ihid = i2c_get_clientdata(client);
 611         int ret;
 612         unsigned int bufsize = HID_MIN_BUFFER_SIZE;
 613
 614         i2c_hid_find_max_report(hid, HID_INPUT_REPORT, &bufsize);
 615         i2c_hid_find_max_report(hid, HID_OUTPUT_REPORT, &bufsize);
 616         i2c_hid_find_max_report(hid, HID_FEATURE_REPORT, &bufsize);
 617
 618         if (bufsize > ihid->bufsize) {
 619                 i2c_hid_free_buffers(ihid);
 620
 621                 ret = i2c_hid_alloc_buffers(ihid, bufsize);
 622
 623                 if (ret)
 624                         return ret;
 625         }
 626
 627         if (!(hid->quirks & HID_QUIRK_NO_INIT_REPORTS))
 628                 i2c_hid_init_reports(hid);
 629
 630         return 0;
 631 }
 632
 633 static void i2c_hid_stop(struct hid_device *hid)
 634 {
 635         struct i2c_client *client = hid->driver_data;
 636         struct i2c_hid *ihid = i2c_get_clientdata(client);
 637
 638         hid->claimed = 0;
 639
 640         i2c_hid_free_buffers(ihid);
 641 }
 642
 643 static int i2c_hid_open(struct hid_device *hid)
 644 {
 645         struct i2c_client *client = hid->driver_data;
 646         struct i2c_hid *ihid = i2c_get_clientdata(client);
 647         int ret = 0;
 648
 649         mutex_lock(&i2c_hid_open_mut);
 650         if (!hid->open++) {
 651                 ret = i2c_hid_set_power(client, I2C_HID_PWR_ON);
 652                 if (ret) {
 653                         hid->open--;
 654                         goto done;
 655                 }
 656                 set_bit(I2C_HID_STARTED, &ihid->flags);
 657         }
 658 done:
 659         mutex_unlock(&i2c_hid_open_mut);
 660         return ret;
 661 }
 662
 663 static void i2c_hid_close(struct hid_device *hid)
 664 {
 665         struct i2c_client *client = hid->driver_data;
 666         struct i2c_hid *ihid = i2c_get_clientdata(client);
 667
 668         /* protecting hid->open to make sure we don't restart
 669          * data acquistion due to a resumption we no longer
 670          * care about
 671          */
 672         mutex_lock(&i2c_hid_open_mut);
 673         if (!--hid->open) {
 674                 clear_bit(I2C_HID_STARTED, &ihid->flags);
 675
 676                 /* Save some power */
 677                 i2c_hid_set_power(client, I2C_HID_PWR_SLEEP);
 678         }
 679         mutex_unlock(&i2c_hid_open_mut);
 680 }
 681
 682 static int i2c_hid_power(struct hid_device *hid, int lvl)
 683 {
 684         struct i2c_client *client = hid->driver_data;
 685         struct i2c_hid *ihid = i2c_get_clientdata(client);
 686         int ret = 0;
 687
 688         i2c_hid_dbg(ihid, "%s lvl:%d\n", __func__, lvl);
 689
 690         switch (lvl) {
 691         case PM_HINT_FULLON:
 692                 ret = i2c_hid_set_power(client, I2C_HID_PWR_ON);
 693                 break;
 694         case PM_HINT_NORMAL:
 695                 ret = i2c_hid_set_power(client, I2C_HID_PWR_SLEEP);
 696                 break;
 697         }
 698         return ret;
 699 }
 700
 701 static int i2c_hid_hidinput_input_event(struct input_dev *dev,
 702                 unsigned int type, unsigned int code, int value)
 703 {
 704         struct hid_device *hid = input_get_drvdata(dev);
 705         struct hid_field *field;
 706         int offset;
 707
 708         if (type == EV_FF)
 709                 return input_ff_event(dev, type, code, value);
 710
 711         if (type != EV_LED)
 712                 return -1;
 713
 714         offset = hidinput_find_field(hid, type, code, &field);
 715
 716         if (offset == -1) {
 717                 hid_warn(dev, "event field not found\n");
 718                 return -1;
 719         }
 720
 721         return hid_set_field(field, offset, value);
 722 }
 723
 724 static struct hid_ll_driver i2c_hid_ll_driver = {
 725         .parse = i2c_hid_parse,
 726         .start = i2c_hid_start,
 727         .stop = i2c_hid_stop,
 728         .open = i2c_hid_open,
 729         .close = i2c_hid_close,
 730         .power = i2c_hid_power,
 731         .hidinput_input_event = i2c_hid_hidinput_input_event,
 732 };
 733
 734 static int i2c_hid_init_irq(struct i2c_client *client)
 735 {
 736         struct i2c_hid *ihid = i2c_get_clientdata(client);
 737         int ret;
 738
 739         dev_dbg(&client->dev, "Requesting IRQ: %d\n", client->irq);
 740
 741         ret = request_threaded_irq(client->irq, NULL, i2c_hid_irq,
 742                         IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
 743                         client->name, ihid);
 744         if (ret < 0) {
 745                 dev_warn(&client->dev,
 746                         "Could not register for %s interrupt, irq = %d,"
 747                         " ret = %d\n",
 748                         client->name, client->irq, ret);
 749
 750                 return ret;
 751         }
 752
 753         return 0;
 754 }
 755
 756 static int i2c_hid_fetch_hid_descriptor(struct i2c_hid *ihid)
 757 {
 758         struct i2c_client *client = ihid->client;
 759         struct i2c_hid_desc *hdesc = &ihid->hdesc;
 760         unsigned int dsize;
 761         int ret;
 762
 763         /* Fetch the length of HID description, retrieve the 4 first bytes:
 764          * bytes 0-1 -> length
 765          * bytes 2-3 -> bcdVersion (has to be 1.00) */
 766         ret = i2c_hid_command(client, &hid_descr_cmd, ihid->hdesc_buffer, 4);
 767
 768         i2c_hid_dbg(ihid, "%s, ihid->hdesc_buffer: %*ph\n",
 769                         __func__, 4, ihid->hdesc_buffer);
 770
 771         if (ret) {
 772                 dev_err(&client->dev,
 773                         "unable to fetch the size of HID descriptor (ret=%d)\n",
 774                         ret);
 775                 return -ENODEV;
 776         }
 777
 778         dsize = le16_to_cpu(hdesc->wHIDDescLength);
 779         /*
 780          * the size of the HID descriptor should at least contain
 781          * its size and the bcdVersion (4 bytes), and should not be greater
 782          * than sizeof(struct i2c_hid_desc) as we directly fill this struct
 783          * through i2c_hid_command.
 784          */
 785         if (dsize < 4 || dsize > sizeof(struct i2c_hid_desc)) {
 786                 dev_err(&client->dev, "weird size of HID descriptor (%u)\n",
 787                         dsize);
 788                 return -ENODEV;
 789         }
 790
 791         /* check bcdVersion == 1.0 */
 792         if (le16_to_cpu(hdesc->bcdVersion) != 0x0100) {
 793                 dev_err(&client->dev,
 794                         "unexpected HID descriptor bcdVersion (0x%04hx)\n",
 795                         le16_to_cpu(hdesc->bcdVersion));
 796                 return -ENODEV;
 797         }
 798
 799         i2c_hid_dbg(ihid, "Fetching the HID descriptor\n");
 800
 801         ret = i2c_hid_command(client, &hid_descr_cmd, ihid->hdesc_buffer,
 802                                 dsize);
 803         if (ret) {
 804                 dev_err(&client->dev, "hid_descr_cmd Fail\n");
 805                 return -ENODEV;
 806         }
 807
 808         i2c_hid_dbg(ihid, "HID Descriptor: %*ph\n", dsize, ihid->hdesc_buffer);
 809
 810         return 0;
 811 }
 812
 813 static int i2c_hid_probe(struct i2c_client *client,
 814                          const struct i2c_device_id *dev_id)
 815 {
 816         int ret;
 817         struct i2c_hid *ihid;
 818         struct hid_device *hid;
 819         __u16 hidRegister;
 820         struct i2c_hid_platform_data *platform_data = client->dev.platform_data;
 821
 822         dbg_hid("HID probe called for i2c 0x%02x\n", client->addr);
 823
 824         if (!platform_data) {
 825                 dev_err(&client->dev, "HID register address not provided\n");
 826                 return -EINVAL;
 827         }
 828
 829         if (!client->irq) {
 830                 dev_err(&client->dev,
 831                         "HID over i2c has not been provided an Int IRQ\n");
 832                 return -EINVAL;
 833         }
 834
 835         ihid = kzalloc(sizeof(struct i2c_hid), GFP_KERNEL);
 836         if (!ihid)
 837                 return -ENOMEM;
 838
 839         i2c_set_clientdata(client, ihid);
 840
 841         ihid->client = client;
 842
 843         hidRegister = platform_data->hid_descriptor_address;
 844         ihid->wHIDDescRegister = cpu_to_le16(hidRegister);
 845
 846         init_waitqueue_head(&ihid->wait);
 847
 848         /* we need to allocate the command buffer without knowing the maximum
 849          * size of the reports. Let's use HID_MIN_BUFFER_SIZE, then we do the
 850          * real computation later. */
 851         ret = i2c_hid_alloc_buffers(ihid, HID_MIN_BUFFER_SIZE);
 852         if (ret < 0)
 853                 goto err;
 854
 855         ret = i2c_hid_fetch_hid_descriptor(ihid);
 856         if (ret < 0)
 857                 goto err;
 858
 859         ret = i2c_hid_init_irq(client);
 860         if (ret < 0)
 861                 goto err;
 862
 863         hid = hid_allocate_device();
 864         if (IS_ERR(hid)) {
 865                 ret = PTR_ERR(hid);
 866                 goto err_irq;
 867         }
 868
 869         ihid->hid = hid;
 870
 871         hid->driver_data = client;
 872         hid->ll_driver = &i2c_hid_ll_driver;
 873         hid->hid_get_raw_report = i2c_hid_get_raw_report;
 874         hid->hid_output_raw_report = i2c_hid_output_raw_report;
 875         hid->dev.parent = &client->dev;
 876         hid->bus = BUS_I2C;
 877         hid->version = le16_to_cpu(ihid->hdesc.bcdVersion);
 878         hid->vendor = le16_to_cpu(ihid->hdesc.wVendorID);
 879         hid->product = le16_to_cpu(ihid->hdesc.wProductID);
 880
 881         snprintf(hid->name, sizeof(hid->name), "%s %04hX:%04hX",
 882                  client->name, hid->vendor, hid->product);
 883
 884         ret = hid_add_device(hid);
 885         if (ret) {
 886                 if (ret != -ENODEV)
 887                         hid_err(client, "can't add hid device: %d\n", ret);
 888                 goto err_mem_free;
 889         }
 890
 891         return 0;
 892
 893 err_mem_free:
 894         hid_destroy_device(hid);
 895
 896 err_irq:
 897         free_irq(client->irq, ihid);
 898
 899 err:
 900         i2c_hid_free_buffers(ihid);
 901         kfree(ihid);
 902         return ret;
 903 }
 904
 905 static int i2c_hid_remove(struct i2c_client *client)
 906 {
 907         struct i2c_hid *ihid = i2c_get_clientdata(client);
 908         struct hid_device *hid;
 909
 910         hid = ihid->hid;
 911         hid_destroy_device(hid);
 912
 913         free_irq(client->irq, ihid);
 914
 915         if (ihid->bufsize)
 916                 i2c_hid_free_buffers(ihid);
 917
 918         kfree(ihid);
 919
 920         return 0;
 921 }
 922
 923 #ifdef CONFIG_PM_SLEEP
 924 static int i2c_hid_suspend(struct device *dev)
 925 {
 926         struct i2c_client *client = to_i2c_client(dev);
 927
 928         if (device_may_wakeup(&client->dev))
 929                 enable_irq_wake(client->irq);
 930
 931         /* Save some power */
 932         i2c_hid_set_power(client, I2C_HID_PWR_SLEEP);
 933
 934         return 0;
 935 }
 936
 937 static int i2c_hid_resume(struct device *dev)
 938 {
 939         int ret;
 940         struct i2c_client *client = to_i2c_client(dev);
 941
 942         ret = i2c_hid_hwreset(client);
 943         if (ret)
 944                 return ret;
 945
 946         if (device_may_wakeup(&client->dev))
 947                 disable_irq_wake(client->irq);
 948
 949         return 0;
 950 }
 951 #endif
 952
 953 static SIMPLE_DEV_PM_OPS(i2c_hid_pm, i2c_hid_suspend, i2c_hid_resume);
 954
 955 static const struct i2c_device_id i2c_hid_id_table[] = {
 956         { "hid", 0 },
 957         { },
 958 };
 959 MODULE_DEVICE_TABLE(i2c, i2c_hid_id_table);
 960
 961
 962 static struct i2c_driver i2c_hid_driver = {
 963         .driver = {
 964                 .name   = "i2c_hid",
 965                 .owner  = THIS_MODULE,
 966                 .pm     = &i2c_hid_pm,
 967         },
 968
 969         .probe          = i2c_hid_probe,
 970         .remove         = i2c_hid_remove,
 971
 972         .id_table       = i2c_hid_id_table,
 973 };
 974
 975 module_i2c_driver(i2c_hid_driver);
 976
 977 MODULE_DESCRIPTION("HID over I2C core driver");
 978 MODULE_AUTHOR("Benjamin Tissoires <benjamin.tissoires@gmail.com>");
 979 MODULE_LICENSE("GPL");