drivers/hid/i2c-hid/i2c-hid-core.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/irq.h>
  26 #include <linux/delay.h>
  27 #include <linux/slab.h>
  28 #include <linux/pm.h>
  29 #include <linux/device.h>
  30 #include <linux/wait.h>
  31 #include <linux/err.h>
  32 #include <linux/string.h>
  33 #include <linux/list.h>
  34 #include <linux/jiffies.h>
  35 #include <linux/kernel.h>
  36 #include <linux/hid.h>
  37 #include <linux/mutex.h>
  38 #include <asm/unaligned.h>
  39
  40 #include "../hid-ids.h"
  41 #include "i2c-hid.h"
  42
  43 /* quirks to control the device */
  44 #define I2C_HID_QUIRK_SET_PWR_WAKEUP_DEV        BIT(0)
  45 #define I2C_HID_QUIRK_NO_IRQ_AFTER_RESET        BIT(1)
  46 #define I2C_HID_QUIRK_BOGUS_IRQ                 BIT(4)
  47 #define I2C_HID_QUIRK_RESET_ON_RESUME           BIT(5)
  48 #define I2C_HID_QUIRK_BAD_INPUT_SIZE            BIT(6)
  49 #define I2C_HID_QUIRK_NO_WAKEUP_AFTER_RESET     BIT(7)
  50
  51 /* Command opcodes */
  52 #define I2C_HID_OPCODE_RESET                    0x01
  53 #define I2C_HID_OPCODE_GET_REPORT               0x02
  54 #define I2C_HID_OPCODE_SET_REPORT               0x03
  55 #define I2C_HID_OPCODE_GET_IDLE                 0x04
  56 #define I2C_HID_OPCODE_SET_IDLE                 0x05
  57 #define I2C_HID_OPCODE_GET_PROTOCOL             0x06
  58 #define I2C_HID_OPCODE_SET_PROTOCOL             0x07
  59 #define I2C_HID_OPCODE_SET_POWER                0x08
  60
  61 /* flags */
  62 #define I2C_HID_STARTED         0
  63 #define I2C_HID_RESET_PENDING   1
  64 #define I2C_HID_READ_PENDING    2
  65
  66 #define I2C_HID_PWR_ON          0x00
  67 #define I2C_HID_PWR_SLEEP       0x01
  68
  69 /* debug option */
  70 static bool debug;
  71 module_param(debug, bool, 0444);
  72 MODULE_PARM_DESC(debug, "print a lot of debug information");
  73
  74 #define i2c_hid_dbg(ihid, fmt, arg...)                                    \
  75 do {                                                                      \
  76         if (debug)                                                        \
  77                 dev_printk(KERN_DEBUG, &(ihid)->client->dev, fmt, ##arg); \
  78 } while (0)
  79
  80 struct i2c_hid_desc {
  81         __le16 wHIDDescLength;
  82         __le16 bcdVersion;
  83         __le16 wReportDescLength;
  84         __le16 wReportDescRegister;
  85         __le16 wInputRegister;
  86         __le16 wMaxInputLength;
  87         __le16 wOutputRegister;
  88         __le16 wMaxOutputLength;
  89         __le16 wCommandRegister;
  90         __le16 wDataRegister;
  91         __le16 wVendorID;
  92         __le16 wProductID;
  93         __le16 wVersionID;
  94         __le32 reserved;
  95 } __packed;
  96
  97 struct i2c_hid_cmd {
  98         unsigned int registerIndex;
  99         __u8 opcode;
 100         unsigned int length;
 101 };
 102
 103 #define I2C_HID_CMD(opcode_) \
 104         .opcode = opcode_, .length = 4, \
 105         .registerIndex = offsetof(struct i2c_hid_desc, wCommandRegister)
 106
 107 /* commands */
 108 static const struct i2c_hid_cmd hid_reset_cmd =         { I2C_HID_CMD(0x01) };
 109 static const struct i2c_hid_cmd hid_get_report_cmd =    { I2C_HID_CMD(0x02) };
 110 static const struct i2c_hid_cmd hid_set_power_cmd =     { I2C_HID_CMD(0x08) };
 111
 112 /*
 113  * These definitions are not used here, but are defined by the spec.
 114  * Keeping them here for documentation purposes.
 115  *
 116  * static const struct i2c_hid_cmd hid_get_idle_cmd = { I2C_HID_CMD(0x04) };
 117  * static const struct i2c_hid_cmd hid_set_idle_cmd = { I2C_HID_CMD(0x05) };
 118  * static const struct i2c_hid_cmd hid_get_protocol_cmd = { I2C_HID_CMD(0x06) };
 119  * static const struct i2c_hid_cmd hid_set_protocol_cmd = { I2C_HID_CMD(0x07) };
 120  */
 121
 122 /* The main device structure */
 123 struct i2c_hid {
 124         struct i2c_client       *client;        /* i2c client */
 125         struct hid_device       *hid;   /* pointer to corresponding HID dev */
 126         union {
 127                 __u8 hdesc_buffer[sizeof(struct i2c_hid_desc)];
 128                 struct i2c_hid_desc hdesc;      /* the HID Descriptor */
 129         };
 130         __le16                  wHIDDescRegister; /* location of the i2c
 131                                                    * register of the HID
 132                                                    * descriptor. */
 133         unsigned int            bufsize;        /* i2c buffer size */
 134         u8                      *inbuf;         /* Input buffer */
 135         u8                      *rawbuf;        /* Raw Input buffer */
 136         u8                      *cmdbuf;        /* Command buffer */
 137
 138         unsigned long           flags;          /* device flags */
 139         unsigned long           quirks;         /* Various quirks */
 140
 141         wait_queue_head_t       wait;           /* For waiting the interrupt */
 142
 143         bool                    irq_wake_enabled;
 144         struct mutex            reset_lock;
 145
 146         struct i2chid_ops       *ops;
 147 };
 148
 149 static const struct i2c_hid_quirks {
 150         __u16 idVendor;
 151         __u16 idProduct;
 152         __u32 quirks;
 153 } i2c_hid_quirks[] = {
 154         { USB_VENDOR_ID_WEIDA, HID_ANY_ID,
 155                 I2C_HID_QUIRK_SET_PWR_WAKEUP_DEV },
 156         { I2C_VENDOR_ID_HANTICK, I2C_PRODUCT_ID_HANTICK_5288,
 157                 I2C_HID_QUIRK_NO_IRQ_AFTER_RESET },
 158         { I2C_VENDOR_ID_ITE, I2C_DEVICE_ID_ITE_VOYO_WINPAD_A15,
 159                 I2C_HID_QUIRK_NO_IRQ_AFTER_RESET },
 160         { I2C_VENDOR_ID_RAYDIUM, I2C_PRODUCT_ID_RAYDIUM_3118,
 161                 I2C_HID_QUIRK_NO_IRQ_AFTER_RESET },
 162         { USB_VENDOR_ID_ALPS_JP, HID_ANY_ID,
 163                  I2C_HID_QUIRK_RESET_ON_RESUME },
 164         { I2C_VENDOR_ID_SYNAPTICS, I2C_PRODUCT_ID_SYNAPTICS_SYNA2393,
 165                  I2C_HID_QUIRK_RESET_ON_RESUME },
 166         { USB_VENDOR_ID_ITE, I2C_DEVICE_ID_ITE_LENOVO_LEGION_Y720,
 167                 I2C_HID_QUIRK_BAD_INPUT_SIZE },
 168         /*
 169          * Sending the wakeup after reset actually break ELAN touchscreen controller
 170          */
 171         { USB_VENDOR_ID_ELAN, HID_ANY_ID,
 172                  I2C_HID_QUIRK_NO_WAKEUP_AFTER_RESET |
 173                  I2C_HID_QUIRK_BOGUS_IRQ },
 174         { 0, 0 }
 175 };
 176
 177 /*
 178  * i2c_hid_lookup_quirk: return any quirks associated with a I2C HID device
 179  * @idVendor: the 16-bit vendor ID
 180  * @idProduct: the 16-bit product ID
 181  *
 182  * Returns: a u32 quirks value.
 183  */
 184 static u32 i2c_hid_lookup_quirk(const u16 idVendor, const u16 idProduct)
 185 {
 186         u32 quirks = 0;
 187         int n;
 188
 189         for (n = 0; i2c_hid_quirks[n].idVendor; n++)
 190                 if (i2c_hid_quirks[n].idVendor == idVendor &&
 191                     (i2c_hid_quirks[n].idProduct == (__u16)HID_ANY_ID ||
 192                      i2c_hid_quirks[n].idProduct == idProduct))
 193                         quirks = i2c_hid_quirks[n].quirks;
 194
 195         return quirks;
 196 }
 197
 198 static int i2c_hid_xfer(struct i2c_hid *ihid,
 199                         u8 *send_buf, int send_len, u8 *recv_buf, int recv_len)
 200 {
 201         struct i2c_client *client = ihid->client;
 202         struct i2c_msg msgs[2] = { 0 };
 203         int n = 0;
 204         int ret;
 205
 206         if (send_len) {
 207                 i2c_hid_dbg(ihid, "%s: cmd=%*ph\n",
 208                             __func__, send_len, send_buf);
 209
 210                 msgs[n].addr = client->addr;
 211                 msgs[n].flags = client->flags & I2C_M_TEN;
 212                 msgs[n].len = send_len;
 213                 msgs[n].buf = send_buf;
 214                 n++;
 215         }
 216
 217         if (recv_len) {
 218                 msgs[n].addr = client->addr;
 219                 msgs[n].flags = (client->flags & I2C_M_TEN) | I2C_M_RD;
 220                 msgs[n].len = recv_len;
 221                 msgs[n].buf = recv_buf;
 222                 n++;
 223
 224                 set_bit(I2C_HID_READ_PENDING, &ihid->flags);
 225         }
 226
 227         ret = i2c_transfer(client->adapter, msgs, n);
 228
 229         if (recv_len)
 230                 clear_bit(I2C_HID_READ_PENDING, &ihid->flags);
 231
 232         if (ret != n)
 233                 return ret < 0 ? ret : -EIO;
 234
 235         return 0;
 236 }
 237
 238 static int i2c_hid_read_register(struct i2c_hid *ihid, __le16 reg,
 239                                  void *buf, size_t len)
 240 {
 241         *(__le16 *)ihid->cmdbuf = reg;
 242
 243         return i2c_hid_xfer(ihid, ihid->cmdbuf, sizeof(__le16), buf, len);
 244 }
 245
 246 static size_t i2c_hid_encode_command(u8 *buf, u8 opcode,
 247                                      int report_type, int report_id)
 248 {
 249         size_t length = 0;
 250
 251         if (report_id < 0x0F) {
 252                 buf[length++] = report_type << 4 | report_id;
 253                 buf[length++] = opcode;
 254         } else {
 255                 buf[length++] = report_type << 4 | 0x0F;
 256                 buf[length++] = opcode;
 257                 buf[length++] = report_id;
 258         }
 259
 260         return length;
 261 }
 262
 263 static int __i2c_hid_command(struct i2c_hid *ihid,
 264                 const struct i2c_hid_cmd *command, u8 reportID,
 265                 u8 reportType, u8 *args, int args_len,
 266                 unsigned char *buf_recv, int data_len)
 267 {
 268         int length = command->length;
 269         unsigned int registerIndex = command->registerIndex;
 270
 271         ihid->cmdbuf[0] = ihid->hdesc_buffer[registerIndex];
 272         ihid->cmdbuf[1] = ihid->hdesc_buffer[registerIndex + 1];
 273
 274         if (length > 2) {
 275                 length = sizeof(__le16) + /* register */
 276                          i2c_hid_encode_command(ihid->cmdbuf + sizeof(__le16),
 277                                                 command->opcode,
 278                                                 reportType, reportID);
 279         }
 280
 281         memcpy(ihid->cmdbuf + length, args, args_len);
 282         length += args_len;
 283
 284         return i2c_hid_xfer(ihid, ihid->cmdbuf, length, buf_recv, data_len);
 285 }
 286
 287 static int i2c_hid_command(struct i2c_hid *ihid,
 288                 const struct i2c_hid_cmd *command,
 289                 unsigned char *buf_recv, int data_len)
 290 {
 291         return __i2c_hid_command(ihid, command, 0, 0, NULL, 0,
 292                                 buf_recv, data_len);
 293 }
 294
 295 static int i2c_hid_get_report(struct i2c_hid *ihid, u8 reportType,
 296                 u8 reportID, unsigned char *buf_recv, int data_len)
 297 {
 298         u8 args[2];
 299         int ret;
 300         int args_len = 0;
 301         u16 readRegister = le16_to_cpu(ihid->hdesc.wDataRegister);
 302
 303         i2c_hid_dbg(ihid, "%s\n", __func__);
 304
 305         args[args_len++] = readRegister & 0xFF;
 306         args[args_len++] = readRegister >> 8;
 307
 308         ret = __i2c_hid_command(ihid, &hid_get_report_cmd, reportID,
 309                 reportType, args, args_len, buf_recv, data_len);
 310         if (ret) {
 311                 dev_err(&ihid->client->dev,
 312                         "failed to retrieve report from device.\n");
 313                 return ret;
 314         }
 315
 316         return 0;
 317 }
 318
 319 static size_t i2c_hid_format_report(u8 *buf, int report_id,
 320                                     const u8 *data, size_t size)
 321 {
 322         size_t length = sizeof(__le16); /* reserve space to store size */
 323
 324         if (report_id)
 325                 buf[length++] = report_id;
 326
 327         memcpy(buf + length, data, size);
 328         length += size;
 329
 330         /* Store overall size in the beginning of the buffer */
 331         put_unaligned_le16(length, buf);
 332
 333         return length;
 334 }
 335
 336 /**
 337  * i2c_hid_set_or_send_report: forward an incoming report to the device
 338  * @ihid: the i2c hid device
 339  * @report_type: 0x03 for HID_FEATURE_REPORT ; 0x02 for HID_OUTPUT_REPORT
 340  * @report_id: the report ID
 341  * @buf: the actual data to transfer, without the report ID
 342  * @data_len: size of buf
 343  * @do_set: true: use SET_REPORT HID command, false: send plain OUTPUT report
 344  */
 345 static int i2c_hid_set_or_send_report(struct i2c_hid *ihid,
 346                                       u8 report_type, u8 report_id,
 347                                       const u8 *buf, size_t data_len,
 348                                       bool do_set)
 349 {
 350         size_t length = 0;
 351         int error;
 352
 353         i2c_hid_dbg(ihid, "%s\n", __func__);
 354
 355         if (data_len > ihid->bufsize)
 356                 return -EINVAL;
 357
 358         if (!do_set && le16_to_cpu(ihid->hdesc.wMaxOutputLength) == 0)
 359                 return -ENOSYS;
 360
 361         if (do_set) {
 362                 /* Command register goes first */
 363                 *(__le16 *)ihid->cmdbuf = ihid->hdesc.wCommandRegister;
 364                 length += sizeof(__le16);
 365                 /* Next is SET_REPORT command */
 366                 length += i2c_hid_encode_command(ihid->cmdbuf + length,
 367                                                  I2C_HID_OPCODE_SET_REPORT,
 368                                                  report_type, report_id);
 369                 /*
 370                  * Report data will go into the data register. Because
 371                  * command can be either 2 or 3 bytes destination for
 372                  * the data register may be not aligned.
 373                 */
 374                 put_unaligned_le16(le16_to_cpu(ihid->hdesc.wDataRegister),
 375                                    ihid->cmdbuf + length);
 376                 length += sizeof(__le16);
 377         } else {
 378                 /*
 379                  * With simple "send report" all data goes into the output
 380                  * register.
 381                  */
 382                 *(__le16 *)ihid->cmdbuf = ihid->hdesc.wOutputRegister;;
 383                 length += sizeof(__le16);
 384         }
 385
 386         length += i2c_hid_format_report(ihid->cmdbuf + length,
 387                                         report_id, buf, data_len);
 388
 389         error = i2c_hid_xfer(ihid, ihid->cmdbuf, length, NULL, 0);
 390         if (error) {
 391                 dev_err(&ihid->client->dev,
 392                         "failed to set a report to device: %d\n", error);
 393                 return error;
 394         }
 395
 396         return data_len;
 397 }
 398
 399 static int i2c_hid_set_power(struct i2c_hid *ihid, int power_state)
 400 {
 401         int ret;
 402
 403         i2c_hid_dbg(ihid, "%s\n", __func__);
 404
 405         /*
 406          * Some devices require to send a command to wakeup before power on.
 407          * The call will get a return value (EREMOTEIO) but device will be
 408          * triggered and activated. After that, it goes like a normal device.
 409          */
 410         if (power_state == I2C_HID_PWR_ON &&
 411             ihid->quirks & I2C_HID_QUIRK_SET_PWR_WAKEUP_DEV) {
 412                 ret = i2c_hid_command(ihid, &hid_set_power_cmd, NULL, 0);
 413
 414                 /* Device was already activated */
 415                 if (!ret)
 416                         goto set_pwr_exit;
 417         }
 418
 419         ret = __i2c_hid_command(ihid, &hid_set_power_cmd, power_state,
 420                 0, NULL, 0, NULL, 0);
 421         if (ret)
 422                 dev_err(&ihid->client->dev,
 423                         "failed to change power setting.\n");
 424
 425 set_pwr_exit:
 426
 427         /*
 428          * The HID over I2C specification states that if a DEVICE needs time
 429          * after the PWR_ON request, it should utilise CLOCK stretching.
 430          * However, it has been observered that the Windows driver provides a
 431          * 1ms sleep between the PWR_ON and RESET requests.
 432          * According to Goodix Windows even waits 60 ms after (other?)
 433          * PWR_ON requests. Testing has confirmed that several devices
 434          * will not work properly without a delay after a PWR_ON request.
 435          */
 436         if (!ret && power_state == I2C_HID_PWR_ON)
 437                 msleep(60);
 438
 439         return ret;
 440 }
 441
 442 static int i2c_hid_execute_reset(struct i2c_hid *ihid)
 443 {
 444         int ret;
 445
 446         i2c_hid_dbg(ihid, "resetting...\n");
 447
 448         set_bit(I2C_HID_RESET_PENDING, &ihid->flags);
 449
 450         ret = i2c_hid_command(ihid, &hid_reset_cmd, NULL, 0);
 451         if (ret) {
 452                 dev_err(&ihid->client->dev, "failed to reset device.\n");
 453                 goto out;
 454         }
 455
 456         if (ihid->quirks & I2C_HID_QUIRK_NO_IRQ_AFTER_RESET) {
 457                 msleep(100);
 458                 goto out;
 459         }
 460
 461         i2c_hid_dbg(ihid, "%s: waiting...\n", __func__);
 462         if (!wait_event_timeout(ihid->wait,
 463                                 !test_bit(I2C_HID_RESET_PENDING, &ihid->flags),
 464                                 msecs_to_jiffies(5000))) {
 465                 ret = -ENODATA;
 466                 goto out;
 467         }
 468         i2c_hid_dbg(ihid, "%s: finished.\n", __func__);
 469
 470 out:
 471         clear_bit(I2C_HID_RESET_PENDING, &ihid->flags);
 472         return ret;
 473 }
 474
 475 static int i2c_hid_hwreset(struct i2c_hid *ihid)
 476 {
 477         int ret;
 478
 479         i2c_hid_dbg(ihid, "%s\n", __func__);
 480
 481         /*
 482          * This prevents sending feature reports while the device is
 483          * being reset. Otherwise we may lose the reset complete
 484          * interrupt.
 485          */
 486         mutex_lock(&ihid->reset_lock);
 487
 488         ret = i2c_hid_set_power(ihid, I2C_HID_PWR_ON);
 489         if (ret)
 490                 goto out_unlock;
 491
 492         ret = i2c_hid_execute_reset(ihid);
 493         if (ret) {
 494                 dev_err(&ihid->client->dev,
 495                         "failed to reset device: %d\n", ret);
 496                 i2c_hid_set_power(ihid, I2C_HID_PWR_SLEEP);
 497                 goto out_unlock;
 498         }
 499
 500         /* At least some SIS devices need this after reset */
 501         if (!(ihid->quirks & I2C_HID_QUIRK_NO_WAKEUP_AFTER_RESET))
 502                 ret = i2c_hid_set_power(ihid, I2C_HID_PWR_ON);
 503
 504 out_unlock:
 505         mutex_unlock(&ihid->reset_lock);
 506         return ret;
 507 }
 508
 509 static void i2c_hid_get_input(struct i2c_hid *ihid)
 510 {
 511         int ret;
 512         u32 ret_size;
 513         int size = le16_to_cpu(ihid->hdesc.wMaxInputLength);
 514
 515         if (size > ihid->bufsize)
 516                 size = ihid->bufsize;
 517
 518         ret = i2c_master_recv(ihid->client, ihid->inbuf, size);
 519         if (ret != size) {
 520                 if (ret < 0)
 521                         return;
 522
 523                 dev_err(&ihid->client->dev, "%s: got %d data instead of %d\n",
 524                         __func__, ret, size);
 525                 return;
 526         }
 527
 528         ret_size = ihid->inbuf[0] | ihid->inbuf[1] << 8;
 529
 530         if (!ret_size) {
 531                 /* host or device initiated RESET completed */
 532                 if (test_and_clear_bit(I2C_HID_RESET_PENDING, &ihid->flags))
 533                         wake_up(&ihid->wait);
 534                 return;
 535         }
 536
 537         if (ihid->quirks & I2C_HID_QUIRK_BOGUS_IRQ && ret_size == 0xffff) {
 538                 dev_warn_once(&ihid->client->dev, "%s: IRQ triggered but "
 539                               "there's no data\n", __func__);
 540                 return;
 541         }
 542
 543         if ((ret_size > size) || (ret_size < 2)) {
 544                 if (ihid->quirks & I2C_HID_QUIRK_BAD_INPUT_SIZE) {
 545                         ihid->inbuf[0] = size & 0xff;
 546                         ihid->inbuf[1] = size >> 8;
 547                         ret_size = size;
 548                 } else {
 549                         dev_err(&ihid->client->dev, "%s: incomplete report (%d/%d)\n",
 550                                 __func__, size, ret_size);
 551                         return;
 552                 }
 553         }
 554
 555         i2c_hid_dbg(ihid, "input: %*ph\n", ret_size, ihid->inbuf);
 556
 557         if (test_bit(I2C_HID_STARTED, &ihid->flags)) {
 558                 pm_wakeup_event(&ihid->client->dev, 0);
 559
 560                 hid_input_report(ihid->hid, HID_INPUT_REPORT, ihid->inbuf + 2,
 561                                 ret_size - 2, 1);
 562         }
 563
 564         return;
 565 }
 566
 567 static irqreturn_t i2c_hid_irq(int irq, void *dev_id)
 568 {
 569         struct i2c_hid *ihid = dev_id;
 570
 571         if (test_bit(I2C_HID_READ_PENDING, &ihid->flags))
 572                 return IRQ_HANDLED;
 573
 574         i2c_hid_get_input(ihid);
 575
 576         return IRQ_HANDLED;
 577 }
 578
 579 static int i2c_hid_get_report_length(struct hid_report *report)
 580 {
 581         return ((report->size - 1) >> 3) + 1 +
 582                 report->device->report_enum[report->type].numbered + 2;
 583 }
 584
 585 /*
 586  * Traverse the supplied list of reports and find the longest
 587  */
 588 static void i2c_hid_find_max_report(struct hid_device *hid, unsigned int type,
 589                 unsigned int *max)
 590 {
 591         struct hid_report *report;
 592         unsigned int size;
 593
 594         /* We should not rely on wMaxInputLength, as some devices may set it to
 595          * a wrong length. */
 596         list_for_each_entry(report, &hid->report_enum[type].report_list, list) {
 597                 size = i2c_hid_get_report_length(report);
 598                 if (*max < size)
 599                         *max = size;
 600         }
 601 }
 602
 603 static void i2c_hid_free_buffers(struct i2c_hid *ihid)
 604 {
 605         kfree(ihid->inbuf);
 606         kfree(ihid->rawbuf);
 607         kfree(ihid->cmdbuf);
 608         ihid->inbuf = NULL;
 609         ihid->rawbuf = NULL;
 610         ihid->cmdbuf = NULL;
 611         ihid->bufsize = 0;
 612 }
 613
 614 static int i2c_hid_alloc_buffers(struct i2c_hid *ihid, size_t report_size)
 615 {
 616         /*
 617          * The worst case is computed from the set_report command with a
 618          * reportID > 15 and the maximum report length.
 619          */
 620         int cmd_len = sizeof(__le16) +  /* command register */
 621                       sizeof(u8) +      /* encoded report type/ID */
 622                       sizeof(u8) +      /* opcode */
 623                       sizeof(u8) +      /* optional 3rd byte report ID */
 624                       sizeof(__le16) +  /* data register */
 625                       sizeof(__le16) +  /* report data size */
 626                       sizeof(u8) +      /* report ID if numbered report */
 627                       report_size;
 628
 629         ihid->inbuf = kzalloc(report_size, GFP_KERNEL);
 630         ihid->rawbuf = kzalloc(report_size, GFP_KERNEL);
 631         ihid->cmdbuf = kzalloc(cmd_len, GFP_KERNEL);
 632
 633         if (!ihid->inbuf || !ihid->rawbuf || !ihid->cmdbuf) {
 634                 i2c_hid_free_buffers(ihid);
 635                 return -ENOMEM;
 636         }
 637
 638         ihid->bufsize = report_size;
 639
 640         return 0;
 641 }
 642
 643 static int i2c_hid_get_raw_report(struct hid_device *hid,
 644                 unsigned char report_number, __u8 *buf, size_t count,
 645                 unsigned char report_type)
 646 {
 647         struct i2c_client *client = hid->driver_data;
 648         struct i2c_hid *ihid = i2c_get_clientdata(client);
 649         size_t ret_count, ask_count;
 650         int ret;
 651
 652         if (report_type == HID_OUTPUT_REPORT)
 653                 return -EINVAL;
 654
 655         /*
 656          * In case of unnumbered reports the response from the device will
 657          * not have the report ID that the upper layers expect, so we need
 658          * to stash it the buffer ourselves and adjust the data size.
 659          */
 660         if (!report_number) {
 661                 buf[0] = 0;
 662                 buf++;
 663                 count--;
 664         }
 665
 666         /* +2 bytes to include the size of the reply in the query buffer */
 667         ask_count = min(count + 2, (size_t)ihid->bufsize);
 668
 669         ret = i2c_hid_get_report(ihid,
 670                         report_type == HID_FEATURE_REPORT ? 0x03 : 0x01,
 671                         report_number, ihid->rawbuf, ask_count);
 672
 673         if (ret < 0)
 674                 return ret;
 675
 676         ret_count = ihid->rawbuf[0] | (ihid->rawbuf[1] << 8);
 677
 678         if (ret_count <= 2)
 679                 return 0;
 680
 681         ret_count = min(ret_count, ask_count);
 682
 683         /* The query buffer contains the size, dropping it in the reply */
 684         count = min(count, ret_count - 2);
 685         memcpy(buf, ihid->rawbuf + 2, count);
 686
 687         if (!report_number)
 688                 count++;
 689
 690         return count;
 691 }
 692
 693 static int i2c_hid_output_raw_report(struct hid_device *hid,
 694                                      const u8 *buf, size_t count,
 695                                      u8 report_type, bool do_set)
 696 {
 697         struct i2c_client *client = hid->driver_data;
 698         struct i2c_hid *ihid = i2c_get_clientdata(client);
 699         int report_id = buf[0];
 700         int ret;
 701
 702         if (report_type == HID_INPUT_REPORT)
 703                 return -EINVAL;
 704
 705         mutex_lock(&ihid->reset_lock);
 706
 707         /*
 708          * Note that both numbered and unnumbered reports passed here
 709          * are supposed to have report ID stored in the 1st byte of the
 710          * buffer, so we strip it off unconditionally before passing payload
 711          * to i2c_hid_set_or_send_report which takes care of encoding
 712          * everything properly.
 713          */
 714         ret = i2c_hid_set_or_send_report(ihid,
 715                                 report_type == HID_FEATURE_REPORT ? 0x03 : 0x02,
 716                                 report_id, buf + 1, count - 1, do_set);
 717
 718         if (ret >= 0)
 719                 ret++; /* add report_id to the number of transferred bytes */
 720
 721         mutex_unlock(&ihid->reset_lock);
 722
 723         return ret;
 724 }
 725
 726 static int i2c_hid_output_report(struct hid_device *hid, u8 *buf, size_t count)
 727 {
 728         return i2c_hid_output_raw_report(hid, buf, count, HID_OUTPUT_REPORT,
 729                                          false);
 730 }
 731
 732 static int i2c_hid_raw_request(struct hid_device *hid, unsigned char reportnum,
 733                                __u8 *buf, size_t len, unsigned char rtype,
 734                                int reqtype)
 735 {
 736         switch (reqtype) {
 737         case HID_REQ_GET_REPORT:
 738                 return i2c_hid_get_raw_report(hid, reportnum, buf, len, rtype);
 739         case HID_REQ_SET_REPORT:
 740                 if (buf[0] != reportnum)
 741                         return -EINVAL;
 742                 return i2c_hid_output_raw_report(hid, buf, len, rtype, true);
 743         default:
 744                 return -EIO;
 745         }
 746 }
 747
 748 static int i2c_hid_parse(struct hid_device *hid)
 749 {
 750         struct i2c_client *client = hid->driver_data;
 751         struct i2c_hid *ihid = i2c_get_clientdata(client);
 752         struct i2c_hid_desc *hdesc = &ihid->hdesc;
 753         unsigned int rsize;
 754         char *rdesc;
 755         int ret;
 756         int tries = 3;
 757         char *use_override;
 758
 759         i2c_hid_dbg(ihid, "entering %s\n", __func__);
 760
 761         rsize = le16_to_cpu(hdesc->wReportDescLength);
 762         if (!rsize || rsize > HID_MAX_DESCRIPTOR_SIZE) {
 763                 dbg_hid("weird size of report descriptor (%u)\n", rsize);
 764                 return -EINVAL;
 765         }
 766
 767         do {
 768                 ret = i2c_hid_hwreset(ihid);
 769                 if (ret)
 770                         msleep(1000);
 771         } while (tries-- > 0 && ret);
 772
 773         if (ret)
 774                 return ret;
 775
 776         use_override = i2c_hid_get_dmi_hid_report_desc_override(client->name,
 777                                                                 &rsize);
 778
 779         if (use_override) {
 780                 rdesc = use_override;
 781                 i2c_hid_dbg(ihid, "Using a HID report descriptor override\n");
 782         } else {
 783                 rdesc = kzalloc(rsize, GFP_KERNEL);
 784
 785                 if (!rdesc) {
 786                         dbg_hid("couldn't allocate rdesc memory\n");
 787                         return -ENOMEM;
 788                 }
 789
 790                 i2c_hid_dbg(ihid, "asking HID report descriptor\n");
 791
 792                 ret = i2c_hid_read_register(ihid,
 793                                             ihid->hdesc.wReportDescRegister,
 794                                             rdesc, rsize);
 795                 if (ret) {
 796                         hid_err(hid, "reading report descriptor failed\n");
 797                         kfree(rdesc);
 798                         return -EIO;
 799                 }
 800         }
 801
 802         i2c_hid_dbg(ihid, "Report Descriptor: %*ph\n", rsize, rdesc);
 803
 804         ret = hid_parse_report(hid, rdesc, rsize);
 805         if (!use_override)
 806                 kfree(rdesc);
 807
 808         if (ret) {
 809                 dbg_hid("parsing report descriptor failed\n");
 810                 return ret;
 811         }
 812
 813         return 0;
 814 }
 815
 816 static int i2c_hid_start(struct hid_device *hid)
 817 {
 818         struct i2c_client *client = hid->driver_data;
 819         struct i2c_hid *ihid = i2c_get_clientdata(client);
 820         int ret;
 821         unsigned int bufsize = HID_MIN_BUFFER_SIZE;
 822
 823         i2c_hid_find_max_report(hid, HID_INPUT_REPORT, &bufsize);
 824         i2c_hid_find_max_report(hid, HID_OUTPUT_REPORT, &bufsize);
 825         i2c_hid_find_max_report(hid, HID_FEATURE_REPORT, &bufsize);
 826
 827         if (bufsize > ihid->bufsize) {
 828                 disable_irq(client->irq);
 829                 i2c_hid_free_buffers(ihid);
 830
 831                 ret = i2c_hid_alloc_buffers(ihid, bufsize);
 832                 enable_irq(client->irq);
 833
 834                 if (ret)
 835                         return ret;
 836         }
 837
 838         return 0;
 839 }
 840
 841 static void i2c_hid_stop(struct hid_device *hid)
 842 {
 843         hid->claimed = 0;
 844 }
 845
 846 static int i2c_hid_open(struct hid_device *hid)
 847 {
 848         struct i2c_client *client = hid->driver_data;
 849         struct i2c_hid *ihid = i2c_get_clientdata(client);
 850
 851         set_bit(I2C_HID_STARTED, &ihid->flags);
 852         return 0;
 853 }
 854
 855 static void i2c_hid_close(struct hid_device *hid)
 856 {
 857         struct i2c_client *client = hid->driver_data;
 858         struct i2c_hid *ihid = i2c_get_clientdata(client);
 859
 860         clear_bit(I2C_HID_STARTED, &ihid->flags);
 861 }
 862
 863 struct hid_ll_driver i2c_hid_ll_driver = {
 864         .parse = i2c_hid_parse,
 865         .start = i2c_hid_start,
 866         .stop = i2c_hid_stop,
 867         .open = i2c_hid_open,
 868         .close = i2c_hid_close,
 869         .output_report = i2c_hid_output_report,
 870         .raw_request = i2c_hid_raw_request,
 871 };
 872 EXPORT_SYMBOL_GPL(i2c_hid_ll_driver);
 873
 874 static int i2c_hid_init_irq(struct i2c_client *client)
 875 {
 876         struct i2c_hid *ihid = i2c_get_clientdata(client);
 877         unsigned long irqflags = 0;
 878         int ret;
 879
 880         dev_dbg(&client->dev, "Requesting IRQ: %d\n", client->irq);
 881
 882         if (!irq_get_trigger_type(client->irq))
 883                 irqflags = IRQF_TRIGGER_LOW;
 884
 885         ret = request_threaded_irq(client->irq, NULL, i2c_hid_irq,
 886                                    irqflags | IRQF_ONESHOT, client->name, ihid);
 887         if (ret < 0) {
 888                 dev_warn(&client->dev,
 889                         "Could not register for %s interrupt, irq = %d,"
 890                         " ret = %d\n",
 891                         client->name, client->irq, ret);
 892
 893                 return ret;
 894         }
 895
 896         return 0;
 897 }
 898
 899 static int i2c_hid_fetch_hid_descriptor(struct i2c_hid *ihid)
 900 {
 901         struct i2c_client *client = ihid->client;
 902         struct i2c_hid_desc *hdesc = &ihid->hdesc;
 903         unsigned int dsize;
 904         int error;
 905
 906         /* i2c hid fetch using a fixed descriptor size (30 bytes) */
 907         if (i2c_hid_get_dmi_i2c_hid_desc_override(client->name)) {
 908                 i2c_hid_dbg(ihid, "Using a HID descriptor override\n");
 909                 ihid->hdesc =
 910                         *i2c_hid_get_dmi_i2c_hid_desc_override(client->name);
 911         } else {
 912                 i2c_hid_dbg(ihid, "Fetching the HID descriptor\n");
 913                 error = i2c_hid_read_register(ihid,
 914                                               ihid->wHIDDescRegister,
 915                                               &ihid->hdesc,
 916                                               sizeof(ihid->hdesc));
 917                 if (error) {
 918                         dev_err(&ihid->client->dev,
 919                                 "failed to fetch HID descriptor: %d\n",
 920                                 error);
 921                         return -ENODEV;
 922                 }
 923         }
 924
 925         /* Validate the length of HID descriptor, the 4 first bytes:
 926          * bytes 0-1 -> length
 927          * bytes 2-3 -> bcdVersion (has to be 1.00) */
 928         /* check bcdVersion == 1.0 */
 929         if (le16_to_cpu(hdesc->bcdVersion) != 0x0100) {
 930                 dev_err(&ihid->client->dev,
 931                         "unexpected HID descriptor bcdVersion (0x%04hx)\n",
 932                         le16_to_cpu(hdesc->bcdVersion));
 933                 return -ENODEV;
 934         }
 935
 936         /* Descriptor length should be 30 bytes as per the specification */
 937         dsize = le16_to_cpu(hdesc->wHIDDescLength);
 938         if (dsize != sizeof(struct i2c_hid_desc)) {
 939                 dev_err(&ihid->client->dev,
 940                         "weird size of HID descriptor (%u)\n", dsize);
 941                 return -ENODEV;
 942         }
 943         i2c_hid_dbg(ihid, "HID Descriptor: %*ph\n", dsize, ihid->hdesc_buffer);
 944         return 0;
 945 }
 946
 947 static int i2c_hid_core_power_up(struct i2c_hid *ihid)
 948 {
 949         if (!ihid->ops->power_up)
 950                 return 0;
 951
 952         return ihid->ops->power_up(ihid->ops);
 953 }
 954
 955 static void i2c_hid_core_power_down(struct i2c_hid *ihid)
 956 {
 957         if (!ihid->ops->power_down)
 958                 return;
 959
 960         ihid->ops->power_down(ihid->ops);
 961 }
 962
 963 static void i2c_hid_core_shutdown_tail(struct i2c_hid *ihid)
 964 {
 965         if (!ihid->ops->shutdown_tail)
 966                 return;
 967
 968         ihid->ops->shutdown_tail(ihid->ops);
 969 }
 970
 971 int i2c_hid_core_probe(struct i2c_client *client, struct i2chid_ops *ops,
 972                        u16 hid_descriptor_address, u32 quirks)
 973 {
 974         int ret;
 975         struct i2c_hid *ihid;
 976         struct hid_device *hid;
 977
 978         dbg_hid("HID probe called for i2c 0x%02x\n", client->addr);
 979
 980         if (!client->irq) {
 981                 dev_err(&client->dev,
 982                         "HID over i2c has not been provided an Int IRQ\n");
 983                 return -EINVAL;
 984         }
 985
 986         if (client->irq < 0) {
 987                 if (client->irq != -EPROBE_DEFER)
 988                         dev_err(&client->dev,
 989                                 "HID over i2c doesn't have a valid IRQ\n");
 990                 return client->irq;
 991         }
 992
 993         ihid = devm_kzalloc(&client->dev, sizeof(*ihid), GFP_KERNEL);
 994         if (!ihid)
 995                 return -ENOMEM;
 996
 997         ihid->ops = ops;
 998
 999         ret = i2c_hid_core_power_up(ihid);
1000         if (ret)
1001                 return ret;
1002
1003         i2c_set_clientdata(client, ihid);
1004
1005         ihid->client = client;
1006
1007         ihid->wHIDDescRegister = cpu_to_le16(hid_descriptor_address);
1008
1009         init_waitqueue_head(&ihid->wait);
1010         mutex_init(&ihid->reset_lock);
1011
1012         /* we need to allocate the command buffer without knowing the maximum
1013          * size of the reports. Let's use HID_MIN_BUFFER_SIZE, then we do the
1014          * real computation later. */
1015         ret = i2c_hid_alloc_buffers(ihid, HID_MIN_BUFFER_SIZE);
1016         if (ret < 0)
1017                 goto err_powered;
1018
1019         device_enable_async_suspend(&client->dev);
1020
1021         /* Make sure there is something at this address */
1022         ret = i2c_smbus_read_byte(client);
1023         if (ret < 0) {
1024                 dev_dbg(&client->dev, "nothing at this address: %d\n", ret);
1025                 ret = -ENXIO;
1026                 goto err_powered;
1027         }
1028
1029         ret = i2c_hid_fetch_hid_descriptor(ihid);
1030         if (ret < 0) {
1031                 dev_err(&client->dev,
1032                         "Failed to fetch the HID Descriptor\n");
1033                 goto err_powered;
1034         }
1035
1036         ret = i2c_hid_init_irq(client);
1037         if (ret < 0)
1038                 goto err_powered;
1039
1040         hid = hid_allocate_device();
1041         if (IS_ERR(hid)) {
1042                 ret = PTR_ERR(hid);
1043                 goto err_irq;
1044         }
1045
1046         ihid->hid = hid;
1047
1048         hid->driver_data = client;
1049         hid->ll_driver = &i2c_hid_ll_driver;
1050         hid->dev.parent = &client->dev;
1051         hid->bus = BUS_I2C;
1052         hid->version = le16_to_cpu(ihid->hdesc.bcdVersion);
1053         hid->vendor = le16_to_cpu(ihid->hdesc.wVendorID);
1054         hid->product = le16_to_cpu(ihid->hdesc.wProductID);
1055
1056         snprintf(hid->name, sizeof(hid->name), "%s %04X:%04X",
1057                  client->name, (u16)hid->vendor, (u16)hid->product);
1058         strlcpy(hid->phys, dev_name(&client->dev), sizeof(hid->phys));
1059
1060         ihid->quirks = i2c_hid_lookup_quirk(hid->vendor, hid->product);
1061
1062         ret = hid_add_device(hid);
1063         if (ret) {
1064                 if (ret != -ENODEV)
1065                         hid_err(client, "can't add hid device: %d\n", ret);
1066                 goto err_mem_free;
1067         }
1068
1069         hid->quirks |= quirks;
1070
1071         return 0;
1072
1073 err_mem_free:
1074         hid_destroy_device(hid);
1075
1076 err_irq:
1077         free_irq(client->irq, ihid);
1078
1079 err_powered:
1080         i2c_hid_core_power_down(ihid);
1081         i2c_hid_free_buffers(ihid);
1082         return ret;
1083 }
1084 EXPORT_SYMBOL_GPL(i2c_hid_core_probe);
1085
1086 int i2c_hid_core_remove(struct i2c_client *client)
1087 {
1088         struct i2c_hid *ihid = i2c_get_clientdata(client);
1089         struct hid_device *hid;
1090
1091         hid = ihid->hid;
1092         hid_destroy_device(hid);
1093
1094         free_irq(client->irq, ihid);
1095
1096         if (ihid->bufsize)
1097                 i2c_hid_free_buffers(ihid);
1098
1099         i2c_hid_core_power_down(ihid);
1100
1101         return 0;
1102 }
1103 EXPORT_SYMBOL_GPL(i2c_hid_core_remove);
1104
1105 void i2c_hid_core_shutdown(struct i2c_client *client)
1106 {
1107         struct i2c_hid *ihid = i2c_get_clientdata(client);
1108
1109         i2c_hid_set_power(ihid, I2C_HID_PWR_SLEEP);
1110         free_irq(client->irq, ihid);
1111
1112         i2c_hid_core_shutdown_tail(ihid);
1113 }
1114 EXPORT_SYMBOL_GPL(i2c_hid_core_shutdown);
1115
1116 #ifdef CONFIG_PM_SLEEP
1117 static int i2c_hid_core_suspend(struct device *dev)
1118 {
1119         struct i2c_client *client = to_i2c_client(dev);
1120         struct i2c_hid *ihid = i2c_get_clientdata(client);
1121         struct hid_device *hid = ihid->hid;
1122         int ret;
1123         int wake_status;
1124
1125         ret = hid_driver_suspend(hid, PMSG_SUSPEND);
1126         if (ret < 0)
1127                 return ret;
1128
1129         /* Save some power */
1130         i2c_hid_set_power(ihid, I2C_HID_PWR_SLEEP);
1131
1132         disable_irq(client->irq);
1133
1134         if (device_may_wakeup(&client->dev)) {
1135                 wake_status = enable_irq_wake(client->irq);
1136                 if (!wake_status)
1137                         ihid->irq_wake_enabled = true;
1138                 else
1139                         hid_warn(hid, "Failed to enable irq wake: %d\n",
1140                                 wake_status);
1141         } else {
1142                 i2c_hid_core_power_down(ihid);
1143         }
1144
1145         return 0;
1146 }
1147
1148 static int i2c_hid_core_resume(struct device *dev)
1149 {
1150         int ret;
1151         struct i2c_client *client = to_i2c_client(dev);
1152         struct i2c_hid *ihid = i2c_get_clientdata(client);
1153         struct hid_device *hid = ihid->hid;
1154         int wake_status;
1155
1156         if (!device_may_wakeup(&client->dev)) {
1157                 i2c_hid_core_power_up(ihid);
1158         } else if (ihid->irq_wake_enabled) {
1159                 wake_status = disable_irq_wake(client->irq);
1160                 if (!wake_status)
1161                         ihid->irq_wake_enabled = false;
1162                 else
1163                         hid_warn(hid, "Failed to disable irq wake: %d\n",
1164                                 wake_status);
1165         }
1166
1167         enable_irq(client->irq);
1168
1169         /* Instead of resetting device, simply powers the device on. This
1170          * solves "incomplete reports" on Raydium devices 2386:3118 and
1171          * 2386:4B33 and fixes various SIS touchscreens no longer sending
1172          * data after a suspend/resume.
1173          *
1174          * However some ALPS touchpads generate IRQ storm without reset, so
1175          * let's still reset them here.
1176          */
1177         if (ihid->quirks & I2C_HID_QUIRK_RESET_ON_RESUME)
1178                 ret = i2c_hid_hwreset(ihid);
1179         else
1180                 ret = i2c_hid_set_power(ihid, I2C_HID_PWR_ON);
1181
1182         if (ret)
1183                 return ret;
1184
1185         return hid_driver_reset_resume(hid);
1186 }
1187 #endif
1188
1189 const struct dev_pm_ops i2c_hid_core_pm = {
1190         SET_SYSTEM_SLEEP_PM_OPS(i2c_hid_core_suspend, i2c_hid_core_resume)
1191 };
1192 EXPORT_SYMBOL_GPL(i2c_hid_core_pm);
1193
1194 MODULE_DESCRIPTION("HID over I2C core driver");
1195 MODULE_AUTHOR("Benjamin Tissoires <benjamin.tissoires@gmail.com>");
1196 MODULE_LICENSE("GPL");