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 #include <linux/acpi.h>
  38 #include <linux/of.h>
  39
  40 #include <linux/i2c/i2c-hid.h>
  41
  42 /* flags */
  43 #define I2C_HID_STARTED         (1 << 0)
  44 #define I2C_HID_RESET_PENDING   (1 << 1)
  45 #define I2C_HID_READ_PENDING    (1 << 2)
  46
  47 #define I2C_HID_PWR_ON          0x00
  48 #define I2C_HID_PWR_SLEEP       0x01
  49
  50 /* debug option */
  51 static bool debug;
  52 module_param(debug, bool, 0444);
  53 MODULE_PARM_DESC(debug, "print a lot of debug information");
  54
  55 #define i2c_hid_dbg(ihid, fmt, arg...)                                    \
  56 do {                                                                      \
  57         if (debug)                                                        \
  58                 dev_printk(KERN_DEBUG, &(ihid)->client->dev, fmt, ##arg); \
  59 } while (0)
  60
  61 struct i2c_hid_desc {
  62         __le16 wHIDDescLength;
  63         __le16 bcdVersion;
  64         __le16 wReportDescLength;
  65         __le16 wReportDescRegister;
  66         __le16 wInputRegister;
  67         __le16 wMaxInputLength;
  68         __le16 wOutputRegister;
  69         __le16 wMaxOutputLength;
  70         __le16 wCommandRegister;
  71         __le16 wDataRegister;
  72         __le16 wVendorID;
  73         __le16 wProductID;
  74         __le16 wVersionID;
  75         __le32 reserved;
  76 } __packed;
  77
  78 struct i2c_hid_cmd {
  79         unsigned int registerIndex;
  80         __u8 opcode;
  81         unsigned int length;
  82         bool wait;
  83 };
  84
  85 union command {
  86         u8 data[0];
  87         struct cmd {
  88                 __le16 reg;
  89                 __u8 reportTypeID;
  90                 __u8 opcode;
  91         } __packed c;
  92 };
  93
  94 #define I2C_HID_CMD(opcode_) \
  95         .opcode = opcode_, .length = 4, \
  96         .registerIndex = offsetof(struct i2c_hid_desc, wCommandRegister)
  97
  98 /* fetch HID descriptor */
  99 static const struct i2c_hid_cmd hid_descr_cmd = { .length = 2 };
 100 /* fetch report descriptors */
 101 static const struct i2c_hid_cmd hid_report_descr_cmd = {
 102                 .registerIndex = offsetof(struct i2c_hid_desc,
 103                         wReportDescRegister),
 104                 .opcode = 0x00,
 105                 .length = 2 };
 106 /* commands */
 107 static const struct i2c_hid_cmd hid_reset_cmd =         { I2C_HID_CMD(0x01),
 108                                                           .wait = true };
 109 static const struct i2c_hid_cmd hid_get_report_cmd =    { I2C_HID_CMD(0x02) };
 110 static const struct i2c_hid_cmd hid_set_report_cmd =    { I2C_HID_CMD(0x03) };
 111 static const struct i2c_hid_cmd hid_set_power_cmd =     { I2C_HID_CMD(0x08) };
 112 static const struct i2c_hid_cmd hid_no_cmd =            { .length = 0 };
 113
 114 /*
 115  * These definitions are not used here, but are defined by the spec.
 116  * Keeping them here for documentation purposes.
 117  *
 118  * static const struct i2c_hid_cmd hid_get_idle_cmd = { I2C_HID_CMD(0x04) };
 119  * static const struct i2c_hid_cmd hid_set_idle_cmd = { I2C_HID_CMD(0x05) };
 120  * static const struct i2c_hid_cmd hid_get_protocol_cmd = { I2C_HID_CMD(0x06) };
 121  * static const struct i2c_hid_cmd hid_set_protocol_cmd = { I2C_HID_CMD(0x07) };
 122  */
 123
 124 static DEFINE_MUTEX(i2c_hid_open_mut);
 125
 126 /* The main device structure */
 127 struct i2c_hid {
 128         struct i2c_client       *client;        /* i2c client */
 129         struct hid_device       *hid;   /* pointer to corresponding HID dev */
 130         union {
 131                 __u8 hdesc_buffer[sizeof(struct i2c_hid_desc)];
 132                 struct i2c_hid_desc hdesc;      /* the HID Descriptor */
 133         };
 134         __le16                  wHIDDescRegister; /* location of the i2c
 135                                                    * register of the HID
 136                                                    * descriptor. */
 137         unsigned int            bufsize;        /* i2c buffer size */
 138         char                    *inbuf;         /* Input buffer */
 139         char                    *cmdbuf;        /* Command buffer */
 140         char                    *argsbuf;       /* Command arguments buffer */
 141
 142         unsigned long           flags;          /* device flags */
 143
 144         wait_queue_head_t       wait;           /* For waiting the interrupt */
 145
 146         struct i2c_hid_platform_data pdata;
 147 };
 148
 149 static int __i2c_hid_command(struct i2c_client *client,
 150                 const struct i2c_hid_cmd *command, u8 reportID,
 151                 u8 reportType, u8 *args, int args_len,
 152                 unsigned char *buf_recv, int data_len)
 153 {
 154         struct i2c_hid *ihid = i2c_get_clientdata(client);
 155         union command *cmd = (union command *)ihid->cmdbuf;
 156         int ret;
 157         struct i2c_msg msg[2];
 158         int msg_num = 1;
 159
 160         int length = command->length;
 161         bool wait = command->wait;
 162         unsigned int registerIndex = command->registerIndex;
 163
 164         /* special case for hid_descr_cmd */
 165         if (command == &hid_descr_cmd) {
 166                 cmd->c.reg = ihid->wHIDDescRegister;
 167         } else {
 168                 cmd->data[0] = ihid->hdesc_buffer[registerIndex];
 169                 cmd->data[1] = ihid->hdesc_buffer[registerIndex + 1];
 170         }
 171
 172         if (length > 2) {
 173                 cmd->c.opcode = command->opcode;
 174                 cmd->c.reportTypeID = reportID | reportType << 4;
 175         }
 176
 177         memcpy(cmd->data + length, args, args_len);
 178         length += args_len;
 179
 180         i2c_hid_dbg(ihid, "%s: cmd=%*ph\n", __func__, length, cmd->data);
 181
 182         msg[0].addr = client->addr;
 183         msg[0].flags = client->flags & I2C_M_TEN;
 184         msg[0].len = length;
 185         msg[0].buf = cmd->data;
 186         if (data_len > 0) {
 187                 msg[1].addr = client->addr;
 188                 msg[1].flags = client->flags & I2C_M_TEN;
 189                 msg[1].flags |= I2C_M_RD;
 190                 msg[1].len = data_len;
 191                 msg[1].buf = buf_recv;
 192                 msg_num = 2;
 193                 set_bit(I2C_HID_READ_PENDING, &ihid->flags);
 194         }
 195
 196         if (wait)
 197                 set_bit(I2C_HID_RESET_PENDING, &ihid->flags);
 198
 199         ret = i2c_transfer(client->adapter, msg, msg_num);
 200
 201         if (data_len > 0)
 202                 clear_bit(I2C_HID_READ_PENDING, &ihid->flags);
 203
 204         if (ret != msg_num)
 205                 return ret < 0 ? ret : -EIO;
 206
 207         ret = 0;
 208
 209         if (wait) {
 210                 i2c_hid_dbg(ihid, "%s: waiting...\n", __func__);
 211                 if (!wait_event_timeout(ihid->wait,
 212                                 !test_bit(I2C_HID_RESET_PENDING, &ihid->flags),
 213                                 msecs_to_jiffies(5000)))
 214                         ret = -ENODATA;
 215                 i2c_hid_dbg(ihid, "%s: finished.\n", __func__);
 216         }
 217
 218         return ret;
 219 }
 220
 221 static int i2c_hid_command(struct i2c_client *client,
 222                 const struct i2c_hid_cmd *command,
 223                 unsigned char *buf_recv, int data_len)
 224 {
 225         return __i2c_hid_command(client, command, 0, 0, NULL, 0,
 226                                 buf_recv, data_len);
 227 }
 228
 229 static int i2c_hid_get_report(struct i2c_client *client, u8 reportType,
 230                 u8 reportID, unsigned char *buf_recv, int data_len)
 231 {
 232         struct i2c_hid *ihid = i2c_get_clientdata(client);
 233         u8 args[3];
 234         int ret;
 235         int args_len = 0;
 236         u16 readRegister = le16_to_cpu(ihid->hdesc.wDataRegister);
 237
 238         i2c_hid_dbg(ihid, "%s\n", __func__);
 239
 240         if (reportID >= 0x0F) {
 241                 args[args_len++] = reportID;
 242                 reportID = 0x0F;
 243         }
 244
 245         args[args_len++] = readRegister & 0xFF;
 246         args[args_len++] = readRegister >> 8;
 247
 248         ret = __i2c_hid_command(client, &hid_get_report_cmd, reportID,
 249                 reportType, args, args_len, buf_recv, data_len);
 250         if (ret) {
 251                 dev_err(&client->dev,
 252                         "failed to retrieve report from device.\n");
 253                 return ret;
 254         }
 255
 256         return 0;
 257 }
 258
 259 static int i2c_hid_set_report(struct i2c_client *client, u8 reportType,
 260                 u8 reportID, unsigned char *buf, size_t data_len)
 261 {
 262         struct i2c_hid *ihid = i2c_get_clientdata(client);
 263         u8 *args = ihid->argsbuf;
 264         const struct i2c_hid_cmd * hidcmd = &hid_set_report_cmd;
 265         int ret;
 266         u16 dataRegister = le16_to_cpu(ihid->hdesc.wDataRegister);
 267         u16 outputRegister = le16_to_cpu(ihid->hdesc.wOutputRegister);
 268         u16 maxOutputLength = le16_to_cpu(ihid->hdesc.wMaxOutputLength);
 269
 270         /* hidraw already checked that data_len < HID_MAX_BUFFER_SIZE */
 271         u16 size =      2                       /* size */ +
 272                         (reportID ? 1 : 0)      /* reportID */ +
 273                         data_len                /* buf */;
 274         int args_len =  (reportID >= 0x0F ? 1 : 0) /* optional third byte */ +
 275                         2                       /* dataRegister */ +
 276                         size                    /* args */;
 277         int index = 0;
 278
 279         i2c_hid_dbg(ihid, "%s\n", __func__);
 280
 281         if (reportID >= 0x0F) {
 282                 args[index++] = reportID;
 283                 reportID = 0x0F;
 284         }
 285
 286         /*
 287          * use the data register for feature reports or if the device does not
 288          * support the output register
 289          */
 290         if (reportType == 0x03 || maxOutputLength == 0) {
 291                 args[index++] = dataRegister & 0xFF;
 292                 args[index++] = dataRegister >> 8;
 293         } else {
 294                 args[index++] = outputRegister & 0xFF;
 295                 args[index++] = outputRegister >> 8;
 296                 hidcmd = &hid_no_cmd;
 297         }
 298
 299         args[index++] = size & 0xFF;
 300         args[index++] = size >> 8;
 301
 302         if (reportID)
 303                 args[index++] = reportID;
 304
 305         memcpy(&args[index], buf, data_len);
 306
 307         ret = __i2c_hid_command(client, hidcmd, reportID,
 308                 reportType, args, args_len, NULL, 0);
 309         if (ret) {
 310                 dev_err(&client->dev, "failed to set a report to device.\n");
 311                 return ret;
 312         }
 313
 314         return data_len;
 315 }
 316
 317 static int i2c_hid_set_power(struct i2c_client *client, int power_state)
 318 {
 319         struct i2c_hid *ihid = i2c_get_clientdata(client);
 320         int ret;
 321
 322         i2c_hid_dbg(ihid, "%s\n", __func__);
 323
 324         ret = __i2c_hid_command(client, &hid_set_power_cmd, power_state,
 325                 0, NULL, 0, NULL, 0);
 326         if (ret)
 327                 dev_err(&client->dev, "failed to change power setting.\n");
 328
 329         return ret;
 330 }
 331
 332 static int i2c_hid_hwreset(struct i2c_client *client)
 333 {
 334         struct i2c_hid *ihid = i2c_get_clientdata(client);
 335         int ret;
 336
 337         i2c_hid_dbg(ihid, "%s\n", __func__);
 338
 339         ret = i2c_hid_set_power(client, I2C_HID_PWR_ON);
 340         if (ret)
 341                 return ret;
 342
 343         i2c_hid_dbg(ihid, "resetting...\n");
 344
 345         ret = i2c_hid_command(client, &hid_reset_cmd, NULL, 0);
 346         if (ret) {
 347                 dev_err(&client->dev, "failed to reset device.\n");
 348                 i2c_hid_set_power(client, I2C_HID_PWR_SLEEP);
 349                 return ret;
 350         }
 351
 352         return 0;
 353 }
 354
 355 static void i2c_hid_get_input(struct i2c_hid *ihid)
 356 {
 357         int ret, ret_size;
 358         int size = le16_to_cpu(ihid->hdesc.wMaxInputLength);
 359
 360         ret = i2c_master_recv(ihid->client, ihid->inbuf, size);
 361         if (ret != size) {
 362                 if (ret < 0)
 363                         return;
 364
 365                 dev_err(&ihid->client->dev, "%s: got %d data instead of %d\n",
 366                         __func__, ret, size);
 367                 return;
 368         }
 369
 370         ret_size = ihid->inbuf[0] | ihid->inbuf[1] << 8;
 371
 372         if (!ret_size) {
 373                 /* host or device initiated RESET completed */
 374                 if (test_and_clear_bit(I2C_HID_RESET_PENDING, &ihid->flags))
 375                         wake_up(&ihid->wait);
 376                 return;
 377         }
 378
 379         if (ret_size > size) {
 380                 dev_err(&ihid->client->dev, "%s: incomplete report (%d/%d)\n",
 381                         __func__, size, ret_size);
 382                 return;
 383         }
 384
 385         i2c_hid_dbg(ihid, "input: %*ph\n", ret_size, ihid->inbuf);
 386
 387         if (test_bit(I2C_HID_STARTED, &ihid->flags))
 388                 hid_input_report(ihid->hid, HID_INPUT_REPORT, ihid->inbuf + 2,
 389                                 ret_size - 2, 1);
 390
 391         return;
 392 }
 393
 394 static irqreturn_t i2c_hid_irq(int irq, void *dev_id)
 395 {
 396         struct i2c_hid *ihid = dev_id;
 397
 398         if (test_bit(I2C_HID_READ_PENDING, &ihid->flags))
 399                 return IRQ_HANDLED;
 400
 401         i2c_hid_get_input(ihid);
 402
 403         return IRQ_HANDLED;
 404 }
 405
 406 static int i2c_hid_get_report_length(struct hid_report *report)
 407 {
 408         return ((report->size - 1) >> 3) + 1 +
 409                 report->device->report_enum[report->type].numbered + 2;
 410 }
 411
 412 static void i2c_hid_init_report(struct hid_report *report, u8 *buffer,
 413         size_t bufsize)
 414 {
 415         struct hid_device *hid = report->device;
 416         struct i2c_client *client = hid->driver_data;
 417         struct i2c_hid *ihid = i2c_get_clientdata(client);
 418         unsigned int size, ret_size;
 419
 420         size = i2c_hid_get_report_length(report);
 421         if (i2c_hid_get_report(client,
 422                         report->type == HID_FEATURE_REPORT ? 0x03 : 0x01,
 423                         report->id, buffer, size))
 424                 return;
 425
 426         i2c_hid_dbg(ihid, "report (len=%d): %*ph\n", size, size, ihid->inbuf);
 427
 428         ret_size = buffer[0] | (buffer[1] << 8);
 429
 430         if (ret_size != size) {
 431                 dev_err(&client->dev, "error in %s size:%d / ret_size:%d\n",
 432                         __func__, size, ret_size);
 433                 return;
 434         }
 435
 436         /* hid->driver_lock is held as we are in probe function,
 437          * we just need to setup the input fields, so using
 438          * hid_report_raw_event is safe. */
 439         hid_report_raw_event(hid, report->type, buffer + 2, size - 2, 1);
 440 }
 441
 442 /*
 443  * Initialize all reports
 444  */
 445 static void i2c_hid_init_reports(struct hid_device *hid)
 446 {
 447         struct hid_report *report;
 448         struct i2c_client *client = hid->driver_data;
 449         struct i2c_hid *ihid = i2c_get_clientdata(client);
 450         u8 *inbuf = kzalloc(ihid->bufsize, GFP_KERNEL);
 451
 452         if (!inbuf) {
 453                 dev_err(&client->dev, "can not retrieve initial reports\n");
 454                 return;
 455         }
 456
 457         list_for_each_entry(report,
 458                 &hid->report_enum[HID_FEATURE_REPORT].report_list, list)
 459                 i2c_hid_init_report(report, inbuf, ihid->bufsize);
 460
 461         kfree(inbuf);
 462 }
 463
 464 /*
 465  * Traverse the supplied list of reports and find the longest
 466  */
 467 static void i2c_hid_find_max_report(struct hid_device *hid, unsigned int type,
 468                 unsigned int *max)
 469 {
 470         struct hid_report *report;
 471         unsigned int size;
 472
 473         /* We should not rely on wMaxInputLength, as some devices may set it to
 474          * a wrong length. */
 475         list_for_each_entry(report, &hid->report_enum[type].report_list, list) {
 476                 size = i2c_hid_get_report_length(report);
 477                 if (*max < size)
 478                         *max = size;
 479         }
 480 }
 481
 482 static void i2c_hid_free_buffers(struct i2c_hid *ihid)
 483 {
 484         kfree(ihid->inbuf);
 485         kfree(ihid->argsbuf);
 486         kfree(ihid->cmdbuf);
 487         ihid->inbuf = NULL;
 488         ihid->cmdbuf = NULL;
 489         ihid->argsbuf = NULL;
 490         ihid->bufsize = 0;
 491 }
 492
 493 static int i2c_hid_alloc_buffers(struct i2c_hid *ihid, size_t report_size)
 494 {
 495         /* the worst case is computed from the set_report command with a
 496          * reportID > 15 and the maximum report length */
 497         int args_len = sizeof(__u8) + /* optional ReportID byte */
 498                        sizeof(__u16) + /* data register */
 499                        sizeof(__u16) + /* size of the report */
 500                        report_size; /* report */
 501
 502         ihid->inbuf = kzalloc(report_size, GFP_KERNEL);
 503         ihid->argsbuf = kzalloc(args_len, GFP_KERNEL);
 504         ihid->cmdbuf = kzalloc(sizeof(union command) + args_len, GFP_KERNEL);
 505
 506         if (!ihid->inbuf || !ihid->argsbuf || !ihid->cmdbuf) {
 507                 i2c_hid_free_buffers(ihid);
 508                 return -ENOMEM;
 509         }
 510
 511         ihid->bufsize = report_size;
 512
 513         return 0;
 514 }
 515
 516 static int i2c_hid_get_raw_report(struct hid_device *hid,
 517                 unsigned char report_number, __u8 *buf, size_t count,
 518                 unsigned char report_type)
 519 {
 520         struct i2c_client *client = hid->driver_data;
 521         struct i2c_hid *ihid = i2c_get_clientdata(client);
 522         size_t ret_count, ask_count;
 523         int ret;
 524
 525         if (report_type == HID_OUTPUT_REPORT)
 526                 return -EINVAL;
 527
 528         /* +2 bytes to include the size of the reply in the query buffer */
 529         ask_count = min(count + 2, (size_t)ihid->bufsize);
 530
 531         ret = i2c_hid_get_report(client,
 532                         report_type == HID_FEATURE_REPORT ? 0x03 : 0x01,
 533                         report_number, ihid->inbuf, ask_count);
 534
 535         if (ret < 0)
 536                 return ret;
 537
 538         ret_count = ihid->inbuf[0] | (ihid->inbuf[1] << 8);
 539
 540         if (ret_count <= 2)
 541                 return 0;
 542
 543         ret_count = min(ret_count, ask_count);
 544
 545         /* The query buffer contains the size, dropping it in the reply */
 546         count = min(count, ret_count - 2);
 547         memcpy(buf, ihid->inbuf + 2, count);
 548
 549         return count;
 550 }
 551
 552 static int i2c_hid_output_raw_report(struct hid_device *hid, __u8 *buf,
 553                 size_t count, unsigned char report_type)
 554 {
 555         struct i2c_client *client = hid->driver_data;
 556         int report_id = buf[0];
 557         int ret;
 558
 559         if (report_type == HID_INPUT_REPORT)
 560                 return -EINVAL;
 561
 562         if (report_id) {
 563                 buf++;
 564                 count--;
 565         }
 566
 567         ret = i2c_hid_set_report(client,
 568                                 report_type == HID_FEATURE_REPORT ? 0x03 : 0x02,
 569                                 report_id, buf, count);
 570
 571         if (report_id && ret >= 0)
 572                 ret++; /* add report_id to the number of transfered bytes */
 573
 574         return ret;
 575 }
 576
 577 static void i2c_hid_request(struct hid_device *hid, struct hid_report *rep,
 578                 int reqtype)
 579 {
 580         struct i2c_client *client = hid->driver_data;
 581         char *buf;
 582         int ret;
 583         int len = i2c_hid_get_report_length(rep) - 2;
 584
 585         buf = hid_alloc_report_buf(rep, GFP_KERNEL);
 586         if (!buf)
 587                 return;
 588
 589         switch (reqtype) {
 590         case HID_REQ_GET_REPORT:
 591                 ret = i2c_hid_get_raw_report(hid, rep->id, buf, len, rep->type);
 592                 if (ret < 0)
 593                         dev_err(&client->dev, "%s: unable to get report: %d\n",
 594                                 __func__, ret);
 595                 else
 596                         hid_input_report(hid, rep->type, buf, ret, 0);
 597                 break;
 598         case HID_REQ_SET_REPORT:
 599                 hid_output_report(rep, buf);
 600                 i2c_hid_output_raw_report(hid, buf, len, rep->type);
 601                 break;
 602         }
 603
 604         kfree(buf);
 605 }
 606
 607 static int i2c_hid_parse(struct hid_device *hid)
 608 {
 609         struct i2c_client *client = hid->driver_data;
 610         struct i2c_hid *ihid = i2c_get_clientdata(client);
 611         struct i2c_hid_desc *hdesc = &ihid->hdesc;
 612         unsigned int rsize;
 613         char *rdesc;
 614         int ret;
 615         int tries = 3;
 616
 617         i2c_hid_dbg(ihid, "entering %s\n", __func__);
 618
 619         rsize = le16_to_cpu(hdesc->wReportDescLength);
 620         if (!rsize || rsize > HID_MAX_DESCRIPTOR_SIZE) {
 621                 dbg_hid("weird size of report descriptor (%u)\n", rsize);
 622                 return -EINVAL;
 623         }
 624
 625         do {
 626                 ret = i2c_hid_hwreset(client);
 627                 if (ret)
 628                         msleep(1000);
 629         } while (tries-- > 0 && ret);
 630
 631         if (ret)
 632                 return ret;
 633
 634         rdesc = kzalloc(rsize, GFP_KERNEL);
 635
 636         if (!rdesc) {
 637                 dbg_hid("couldn't allocate rdesc memory\n");
 638                 return -ENOMEM;
 639         }
 640
 641         i2c_hid_dbg(ihid, "asking HID report descriptor\n");
 642
 643         ret = i2c_hid_command(client, &hid_report_descr_cmd, rdesc, rsize);
 644         if (ret) {
 645                 hid_err(hid, "reading report descriptor failed\n");
 646                 kfree(rdesc);
 647                 return -EIO;
 648         }
 649
 650         i2c_hid_dbg(ihid, "Report Descriptor: %*ph\n", rsize, rdesc);
 651
 652         ret = hid_parse_report(hid, rdesc, rsize);
 653         kfree(rdesc);
 654         if (ret) {
 655                 dbg_hid("parsing report descriptor failed\n");
 656                 return ret;
 657         }
 658
 659         return 0;
 660 }
 661
 662 static int i2c_hid_start(struct hid_device *hid)
 663 {
 664         struct i2c_client *client = hid->driver_data;
 665         struct i2c_hid *ihid = i2c_get_clientdata(client);
 666         int ret;
 667         unsigned int bufsize = HID_MIN_BUFFER_SIZE;
 668
 669         i2c_hid_find_max_report(hid, HID_INPUT_REPORT, &bufsize);
 670         i2c_hid_find_max_report(hid, HID_OUTPUT_REPORT, &bufsize);
 671         i2c_hid_find_max_report(hid, HID_FEATURE_REPORT, &bufsize);
 672
 673         if (bufsize > ihid->bufsize) {
 674                 i2c_hid_free_buffers(ihid);
 675
 676                 ret = i2c_hid_alloc_buffers(ihid, bufsize);
 677
 678                 if (ret)
 679                         return ret;
 680         }
 681
 682         if (!(hid->quirks & HID_QUIRK_NO_INIT_REPORTS))
 683                 i2c_hid_init_reports(hid);
 684
 685         return 0;
 686 }
 687
 688 static void i2c_hid_stop(struct hid_device *hid)
 689 {
 690         struct i2c_client *client = hid->driver_data;
 691         struct i2c_hid *ihid = i2c_get_clientdata(client);
 692
 693         hid->claimed = 0;
 694
 695         i2c_hid_free_buffers(ihid);
 696 }
 697
 698 static int i2c_hid_open(struct hid_device *hid)
 699 {
 700         struct i2c_client *client = hid->driver_data;
 701         struct i2c_hid *ihid = i2c_get_clientdata(client);
 702         int ret = 0;
 703
 704         mutex_lock(&i2c_hid_open_mut);
 705         if (!hid->open++) {
 706                 ret = i2c_hid_set_power(client, I2C_HID_PWR_ON);
 707                 if (ret) {
 708                         hid->open--;
 709                         goto done;
 710                 }
 711                 set_bit(I2C_HID_STARTED, &ihid->flags);
 712         }
 713 done:
 714         mutex_unlock(&i2c_hid_open_mut);
 715         return ret;
 716 }
 717
 718 static void i2c_hid_close(struct hid_device *hid)
 719 {
 720         struct i2c_client *client = hid->driver_data;
 721         struct i2c_hid *ihid = i2c_get_clientdata(client);
 722
 723         /* protecting hid->open to make sure we don't restart
 724          * data acquistion due to a resumption we no longer
 725          * care about
 726          */
 727         mutex_lock(&i2c_hid_open_mut);
 728         if (!--hid->open) {
 729                 clear_bit(I2C_HID_STARTED, &ihid->flags);
 730
 731                 /* Save some power */
 732                 i2c_hid_set_power(client, I2C_HID_PWR_SLEEP);
 733         }
 734         mutex_unlock(&i2c_hid_open_mut);
 735 }
 736
 737 static int i2c_hid_power(struct hid_device *hid, int lvl)
 738 {
 739         struct i2c_client *client = hid->driver_data;
 740         struct i2c_hid *ihid = i2c_get_clientdata(client);
 741         int ret = 0;
 742
 743         i2c_hid_dbg(ihid, "%s lvl:%d\n", __func__, lvl);
 744
 745         switch (lvl) {
 746         case PM_HINT_FULLON:
 747                 ret = i2c_hid_set_power(client, I2C_HID_PWR_ON);
 748                 break;
 749         case PM_HINT_NORMAL:
 750                 ret = i2c_hid_set_power(client, I2C_HID_PWR_SLEEP);
 751                 break;
 752         }
 753         return ret;
 754 }
 755
 756 static struct hid_ll_driver i2c_hid_ll_driver = {
 757         .parse = i2c_hid_parse,
 758         .start = i2c_hid_start,
 759         .stop = i2c_hid_stop,
 760         .open = i2c_hid_open,
 761         .close = i2c_hid_close,
 762         .power = i2c_hid_power,
 763         .request = i2c_hid_request,
 764 };
 765
 766 static int i2c_hid_init_irq(struct i2c_client *client)
 767 {
 768         struct i2c_hid *ihid = i2c_get_clientdata(client);
 769         int ret;
 770
 771         dev_dbg(&client->dev, "Requesting IRQ: %d\n", client->irq);
 772
 773         ret = request_threaded_irq(client->irq, NULL, i2c_hid_irq,
 774                         IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
 775                         client->name, ihid);
 776         if (ret < 0) {
 777                 dev_warn(&client->dev,
 778                         "Could not register for %s interrupt, irq = %d,"
 779                         " ret = %d\n",
 780                         client->name, client->irq, ret);
 781
 782                 return ret;
 783         }
 784
 785         return 0;
 786 }
 787
 788 static int i2c_hid_fetch_hid_descriptor(struct i2c_hid *ihid)
 789 {
 790         struct i2c_client *client = ihid->client;
 791         struct i2c_hid_desc *hdesc = &ihid->hdesc;
 792         unsigned int dsize;
 793         int ret;
 794
 795         /* Fetch the length of HID description, retrieve the 4 first bytes:
 796          * bytes 0-1 -> length
 797          * bytes 2-3 -> bcdVersion (has to be 1.00) */
 798         ret = i2c_hid_command(client, &hid_descr_cmd, ihid->hdesc_buffer, 4);
 799
 800         i2c_hid_dbg(ihid, "%s, ihid->hdesc_buffer: %4ph\n", __func__,
 801                         ihid->hdesc_buffer);
 802
 803         if (ret) {
 804                 dev_err(&client->dev,
 805                         "unable to fetch the size of HID descriptor (ret=%d)\n",
 806                         ret);
 807                 return -ENODEV;
 808         }
 809
 810         dsize = le16_to_cpu(hdesc->wHIDDescLength);
 811         /*
 812          * the size of the HID descriptor should at least contain
 813          * its size and the bcdVersion (4 bytes), and should not be greater
 814          * than sizeof(struct i2c_hid_desc) as we directly fill this struct
 815          * through i2c_hid_command.
 816          */
 817         if (dsize < 4 || dsize > sizeof(struct i2c_hid_desc)) {
 818                 dev_err(&client->dev, "weird size of HID descriptor (%u)\n",
 819                         dsize);
 820                 return -ENODEV;
 821         }
 822
 823         /* check bcdVersion == 1.0 */
 824         if (le16_to_cpu(hdesc->bcdVersion) != 0x0100) {
 825                 dev_err(&client->dev,
 826                         "unexpected HID descriptor bcdVersion (0x%04hx)\n",
 827                         le16_to_cpu(hdesc->bcdVersion));
 828                 return -ENODEV;
 829         }
 830
 831         i2c_hid_dbg(ihid, "Fetching the HID descriptor\n");
 832
 833         ret = i2c_hid_command(client, &hid_descr_cmd, ihid->hdesc_buffer,
 834                                 dsize);
 835         if (ret) {
 836                 dev_err(&client->dev, "hid_descr_cmd Fail\n");
 837                 return -ENODEV;
 838         }
 839
 840         i2c_hid_dbg(ihid, "HID Descriptor: %*ph\n", dsize, ihid->hdesc_buffer);
 841
 842         return 0;
 843 }
 844
 845 #ifdef CONFIG_ACPI
 846 static int i2c_hid_acpi_pdata(struct i2c_client *client,
 847                 struct i2c_hid_platform_data *pdata)
 848 {
 849         static u8 i2c_hid_guid[] = {
 850                 0xF7, 0xF6, 0xDF, 0x3C, 0x67, 0x42, 0x55, 0x45,
 851                 0xAD, 0x05, 0xB3, 0x0A, 0x3D, 0x89, 0x38, 0xDE,
 852         };
 853         union acpi_object *obj;
 854         struct acpi_device *adev;
 855         acpi_handle handle;
 856
 857         handle = ACPI_HANDLE(&client->dev);
 858         if (!handle || acpi_bus_get_device(handle, &adev))
 859                 return -ENODEV;
 860
 861         obj = acpi_evaluate_dsm_typed(handle, i2c_hid_guid, 1, 1, NULL,
 862                                       ACPI_TYPE_INTEGER);
 863         if (!obj) {
 864                 dev_err(&client->dev, "device _DSM execution failed\n");
 865                 return -ENODEV;
 866         }
 867
 868         pdata->hid_descriptor_address = obj->integer.value;
 869         ACPI_FREE(obj);
 870
 871         return 0;
 872 }
 873
 874 static const struct acpi_device_id i2c_hid_acpi_match[] = {
 875         {"ACPI0C50", 0 },
 876         {"PNP0C50", 0 },
 877         { },
 878 };
 879 MODULE_DEVICE_TABLE(acpi, i2c_hid_acpi_match);
 880 #else
 881 static inline int i2c_hid_acpi_pdata(struct i2c_client *client,
 882                 struct i2c_hid_platform_data *pdata)
 883 {
 884         return -ENODEV;
 885 }
 886 #endif
 887
 888 #ifdef CONFIG_OF
 889 static int i2c_hid_of_probe(struct i2c_client *client,
 890                 struct i2c_hid_platform_data *pdata)
 891 {
 892         struct device *dev = &client->dev;
 893         u32 val;
 894         int ret;
 895
 896         ret = of_property_read_u32(dev->of_node, "hid-descr-addr", &val);
 897         if (ret) {
 898                 dev_err(&client->dev, "HID register address not provided\n");
 899                 return -ENODEV;
 900         }
 901         if (val >> 16) {
 902                 dev_err(&client->dev, "Bad HID register address: 0x%08x\n",
 903                         val);
 904                 return -EINVAL;
 905         }
 906         pdata->hid_descriptor_address = val;
 907
 908         return 0;
 909 }
 910
 911 static const struct of_device_id i2c_hid_of_match[] = {
 912         { .compatible = "hid-over-i2c" },
 913         {},
 914 };
 915 MODULE_DEVICE_TABLE(of, i2c_hid_of_match);
 916 #else
 917 static inline int i2c_hid_of_probe(struct i2c_client *client,
 918                 struct i2c_hid_platform_data *pdata)
 919 {
 920         return -ENODEV;
 921 }
 922 #endif
 923
 924 static int i2c_hid_probe(struct i2c_client *client,
 925                          const struct i2c_device_id *dev_id)
 926 {
 927         int ret;
 928         struct i2c_hid *ihid;
 929         struct hid_device *hid;
 930         __u16 hidRegister;
 931         struct i2c_hid_platform_data *platform_data = client->dev.platform_data;
 932
 933         dbg_hid("HID probe called for i2c 0x%02x\n", client->addr);
 934
 935         if (!client->irq) {
 936                 dev_err(&client->dev,
 937                         "HID over i2c has not been provided an Int IRQ\n");
 938                 return -EINVAL;
 939         }
 940
 941         ihid = kzalloc(sizeof(struct i2c_hid), GFP_KERNEL);
 942         if (!ihid)
 943                 return -ENOMEM;
 944
 945         if (client->dev.of_node) {
 946                 ret = i2c_hid_of_probe(client, &ihid->pdata);
 947                 if (ret)
 948                         goto err;
 949         } else if (!platform_data) {
 950                 ret = i2c_hid_acpi_pdata(client, &ihid->pdata);
 951                 if (ret) {
 952                         dev_err(&client->dev,
 953                                 "HID register address not provided\n");
 954                         goto err;
 955                 }
 956         } else {
 957                 ihid->pdata = *platform_data;
 958         }
 959
 960         i2c_set_clientdata(client, ihid);
 961
 962         ihid->client = client;
 963
 964         hidRegister = ihid->pdata.hid_descriptor_address;
 965         ihid->wHIDDescRegister = cpu_to_le16(hidRegister);
 966
 967         init_waitqueue_head(&ihid->wait);
 968
 969         /* we need to allocate the command buffer without knowing the maximum
 970          * size of the reports. Let's use HID_MIN_BUFFER_SIZE, then we do the
 971          * real computation later. */
 972         ret = i2c_hid_alloc_buffers(ihid, HID_MIN_BUFFER_SIZE);
 973         if (ret < 0)
 974                 goto err;
 975
 976         ret = i2c_hid_fetch_hid_descriptor(ihid);
 977         if (ret < 0)
 978                 goto err;
 979
 980         ret = i2c_hid_init_irq(client);
 981         if (ret < 0)
 982                 goto err;
 983
 984         hid = hid_allocate_device();
 985         if (IS_ERR(hid)) {
 986                 ret = PTR_ERR(hid);
 987                 goto err_irq;
 988         }
 989
 990         ihid->hid = hid;
 991
 992         hid->driver_data = client;
 993         hid->ll_driver = &i2c_hid_ll_driver;
 994         hid->hid_get_raw_report = i2c_hid_get_raw_report;
 995         hid->hid_output_raw_report = i2c_hid_output_raw_report;
 996         hid->dev.parent = &client->dev;
 997         ACPI_COMPANION_SET(&hid->dev, ACPI_COMPANION(&client->dev));
 998         hid->bus = BUS_I2C;
 999         hid->version = le16_to_cpu(ihid->hdesc.bcdVersion);
1000         hid->vendor = le16_to_cpu(ihid->hdesc.wVendorID);
1001         hid->product = le16_to_cpu(ihid->hdesc.wProductID);
1002
1003         snprintf(hid->name, sizeof(hid->name), "%s %04hX:%04hX",
1004                  client->name, hid->vendor, hid->product);
1005
1006         ret = hid_add_device(hid);
1007         if (ret) {
1008                 if (ret != -ENODEV)
1009                         hid_err(client, "can't add hid device: %d\n", ret);
1010                 goto err_mem_free;
1011         }
1012
1013         return 0;
1014
1015 err_mem_free:
1016         hid_destroy_device(hid);
1017
1018 err_irq:
1019         free_irq(client->irq, ihid);
1020
1021 err:
1022         i2c_hid_free_buffers(ihid);
1023         kfree(ihid);
1024         return ret;
1025 }
1026
1027 static int i2c_hid_remove(struct i2c_client *client)
1028 {
1029         struct i2c_hid *ihid = i2c_get_clientdata(client);
1030         struct hid_device *hid;
1031
1032         hid = ihid->hid;
1033         hid_destroy_device(hid);
1034
1035         free_irq(client->irq, ihid);
1036
1037         if (ihid->bufsize)
1038                 i2c_hid_free_buffers(ihid);
1039
1040         kfree(ihid);
1041
1042         return 0;
1043 }
1044
1045 #ifdef CONFIG_PM_SLEEP
1046 static int i2c_hid_suspend(struct device *dev)
1047 {
1048         struct i2c_client *client = to_i2c_client(dev);
1049
1050         disable_irq(client->irq);
1051         if (device_may_wakeup(&client->dev))
1052                 enable_irq_wake(client->irq);
1053
1054         /* Save some power */
1055         i2c_hid_set_power(client, I2C_HID_PWR_SLEEP);
1056
1057         return 0;
1058 }
1059
1060 static int i2c_hid_resume(struct device *dev)
1061 {
1062         int ret;
1063         struct i2c_client *client = to_i2c_client(dev);
1064
1065         enable_irq(client->irq);
1066         ret = i2c_hid_hwreset(client);
1067         if (ret)
1068                 return ret;
1069
1070         if (device_may_wakeup(&client->dev))
1071                 disable_irq_wake(client->irq);
1072
1073         return 0;
1074 }
1075 #endif
1076
1077 static SIMPLE_DEV_PM_OPS(i2c_hid_pm, i2c_hid_suspend, i2c_hid_resume);
1078
1079 static const struct i2c_device_id i2c_hid_id_table[] = {
1080         { "hid", 0 },
1081         { },
1082 };
1083 MODULE_DEVICE_TABLE(i2c, i2c_hid_id_table);
1084
1085
1086 static struct i2c_driver i2c_hid_driver = {
1087         .driver = {
1088                 .name   = "i2c_hid",
1089                 .owner  = THIS_MODULE,
1090                 .pm     = &i2c_hid_pm,
1091                 .acpi_match_table = ACPI_PTR(i2c_hid_acpi_match),
1092                 .of_match_table = of_match_ptr(i2c_hid_of_match),
1093         },
1094
1095         .probe          = i2c_hid_probe,
1096         .remove         = i2c_hid_remove,
1097
1098         .id_table       = i2c_hid_id_table,
1099 };
1100
1101 module_i2c_driver(i2c_hid_driver);
1102
1103 MODULE_DESCRIPTION("HID over I2C core driver");
1104 MODULE_AUTHOR("Benjamin Tissoires <benjamin.tissoires@gmail.com>");
1105 MODULE_LICENSE("GPL");