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