drivers/hid/hid-mcp2221.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * MCP2221A - Microchip USB to I2C Host Protocol Bridge
   4  *
   5  * Copyright (c) 2020, Rishi Gupta <gupt21@gmail.com>
   6  *
   7  * Datasheet: https://ww1.microchip.com/downloads/en/DeviceDoc/20005565B.pdf
   8  */
   9
  10 #include <linux/module.h>
  11 #include <linux/err.h>
  12 #include <linux/mutex.h>
  13 #include <linux/completion.h>
  14 #include <linux/delay.h>
  15 #include <linux/hid.h>
  16 #include <linux/hidraw.h>
  17 #include <linux/i2c.h>
  18 #include <linux/gpio/driver.h>
  19 #include "hid-ids.h"
  20
  21 /* Commands codes in a raw output report */
  22 enum {
  23         MCP2221_I2C_WR_DATA = 0x90,
  24         MCP2221_I2C_WR_NO_STOP = 0x94,
  25         MCP2221_I2C_RD_DATA = 0x91,
  26         MCP2221_I2C_RD_RPT_START = 0x93,
  27         MCP2221_I2C_GET_DATA = 0x40,
  28         MCP2221_I2C_PARAM_OR_STATUS     = 0x10,
  29         MCP2221_I2C_SET_SPEED = 0x20,
  30         MCP2221_I2C_CANCEL = 0x10,
  31         MCP2221_GPIO_SET = 0x50,
  32         MCP2221_GPIO_GET = 0x51,
  33 };
  34
  35 /* Response codes in a raw input report */
  36 enum {
  37         MCP2221_SUCCESS = 0x00,
  38         MCP2221_I2C_ENG_BUSY = 0x01,
  39         MCP2221_I2C_START_TOUT = 0x12,
  40         MCP2221_I2C_STOP_TOUT = 0x62,
  41         MCP2221_I2C_WRADDRL_TOUT = 0x23,
  42         MCP2221_I2C_WRDATA_TOUT = 0x44,
  43         MCP2221_I2C_WRADDRL_NACK = 0x25,
  44         MCP2221_I2C_MASK_ADDR_NACK = 0x40,
  45         MCP2221_I2C_WRADDRL_SEND = 0x21,
  46         MCP2221_I2C_ADDR_NACK = 0x25,
  47         MCP2221_I2C_READ_COMPL = 0x55,
  48         MCP2221_ALT_F_NOT_GPIOV = 0xEE,
  49         MCP2221_ALT_F_NOT_GPIOD = 0xEF,
  50 };
  51
  52 /*
  53  * There is no way to distinguish responses. Therefore next command
  54  * is sent only after response to previous has been received. Mutex
  55  * lock is used for this purpose mainly.
  56  */
  57 struct mcp2221 {
  58         struct hid_device *hdev;
  59         struct i2c_adapter adapter;
  60         struct mutex lock;
  61         struct completion wait_in_report;
  62         u8 *rxbuf;
  63         u8 txbuf[64];
  64         int rxbuf_idx;
  65         int status;
  66         u8 cur_i2c_clk_div;
  67         struct gpio_chip *gc;
  68         u8 gp_idx;
  69         u8 gpio_dir;
  70 };
  71
  72 /*
  73  * Default i2c bus clock frequency 400 kHz. Modify this if you
  74  * want to set some other frequency (min 50 kHz - max 400 kHz).
  75  */
  76 static uint i2c_clk_freq = 400;
  77
  78 /* Synchronously send output report to the device */
  79 static int mcp_send_report(struct mcp2221 *mcp,
  80                                         u8 *out_report, size_t len)
  81 {
  82         u8 *buf;
  83         int ret;
  84
  85         buf = kmemdup(out_report, len, GFP_KERNEL);
  86         if (!buf)
  87                 return -ENOMEM;
  88
  89         /* mcp2221 uses interrupt endpoint for out reports */
  90         ret = hid_hw_output_report(mcp->hdev, buf, len);
  91         kfree(buf);
  92
  93         if (ret < 0)
  94                 return ret;
  95         return 0;
  96 }
  97
  98 /*
  99  * Send o/p report to the device and wait for i/p report to be
 100  * received from the device. If the device does not respond,
 101  * we timeout.
 102  */
 103 static int mcp_send_data_req_status(struct mcp2221 *mcp,
 104                         u8 *out_report, int len)
 105 {
 106         int ret;
 107         unsigned long t;
 108
 109         reinit_completion(&mcp->wait_in_report);
 110
 111         ret = mcp_send_report(mcp, out_report, len);
 112         if (ret)
 113                 return ret;
 114
 115         t = wait_for_completion_timeout(&mcp->wait_in_report,
 116                                                         msecs_to_jiffies(4000));
 117         if (!t)
 118                 return -ETIMEDOUT;
 119
 120         return mcp->status;
 121 }
 122
 123 /* Check pass/fail for actual communication with i2c slave */
 124 static int mcp_chk_last_cmd_status(struct mcp2221 *mcp)
 125 {
 126         memset(mcp->txbuf, 0, 8);
 127         mcp->txbuf[0] = MCP2221_I2C_PARAM_OR_STATUS;
 128
 129         return mcp_send_data_req_status(mcp, mcp->txbuf, 8);
 130 }
 131
 132 /* Cancels last command releasing i2c bus just in case occupied */
 133 static int mcp_cancel_last_cmd(struct mcp2221 *mcp)
 134 {
 135         memset(mcp->txbuf, 0, 8);
 136         mcp->txbuf[0] = MCP2221_I2C_PARAM_OR_STATUS;
 137         mcp->txbuf[2] = MCP2221_I2C_CANCEL;
 138
 139         return mcp_send_data_req_status(mcp, mcp->txbuf, 8);
 140 }
 141
 142 static int mcp_set_i2c_speed(struct mcp2221 *mcp)
 143 {
 144         int ret;
 145
 146         memset(mcp->txbuf, 0, 8);
 147         mcp->txbuf[0] = MCP2221_I2C_PARAM_OR_STATUS;
 148         mcp->txbuf[3] = MCP2221_I2C_SET_SPEED;
 149         mcp->txbuf[4] = mcp->cur_i2c_clk_div;
 150
 151         ret = mcp_send_data_req_status(mcp, mcp->txbuf, 8);
 152         if (ret) {
 153                 /* Small delay is needed here */
 154                 usleep_range(980, 1000);
 155                 mcp_cancel_last_cmd(mcp);
 156         }
 157
 158         return 0;
 159 }
 160
 161 /*
 162  * An output report can contain minimum 1 and maximum 60 user data
 163  * bytes. If the number of data bytes is more then 60, we send it
 164  * in chunks of 60 bytes. Last chunk may contain exactly 60 or less
 165  * bytes. Total number of bytes is informed in very first report to
 166  * mcp2221, from that point onwards it first collect all the data
 167  * from host and then send to i2c slave device.
 168  */
 169 static int mcp_i2c_write(struct mcp2221 *mcp,
 170                                 struct i2c_msg *msg, int type, u8 last_status)
 171 {
 172         int ret, len, idx, sent;
 173
 174         idx = 0;
 175         sent  = 0;
 176         if (msg->len < 60)
 177                 len = msg->len;
 178         else
 179                 len = 60;
 180
 181         do {
 182                 mcp->txbuf[0] = type;
 183                 mcp->txbuf[1] = msg->len & 0xff;
 184                 mcp->txbuf[2] = msg->len >> 8;
 185                 mcp->txbuf[3] = (u8)(msg->addr << 1);
 186
 187                 memcpy(&mcp->txbuf[4], &msg->buf[idx], len);
 188
 189                 ret = mcp_send_data_req_status(mcp, mcp->txbuf, len + 4);
 190                 if (ret)
 191                         return ret;
 192
 193                 usleep_range(980, 1000);
 194
 195                 if (last_status) {
 196                         ret = mcp_chk_last_cmd_status(mcp);
 197                         if (ret)
 198                                 return ret;
 199                 }
 200
 201                 sent = sent + len;
 202                 if (sent >= msg->len)
 203                         break;
 204
 205                 idx = idx + len;
 206                 if ((msg->len - sent) < 60)
 207                         len = msg->len - sent;
 208                 else
 209                         len = 60;
 210
 211                 /*
 212                  * Testing shows delay is needed between successive writes
 213                  * otherwise next write fails on first-try from i2c core.
 214                  * This value is obtained through automated stress testing.
 215                  */
 216                 usleep_range(980, 1000);
 217         } while (len > 0);
 218
 219         return ret;
 220 }
 221
 222 /*
 223  * Device reads all data (0 - 65535 bytes) from i2c slave device and
 224  * stores it in device itself. This data is read back from device to
 225  * host in multiples of 60 bytes using input reports.
 226  */
 227 static int mcp_i2c_smbus_read(struct mcp2221 *mcp,
 228                                 struct i2c_msg *msg, int type, u16 smbus_addr,
 229                                 u8 smbus_len, u8 *smbus_buf)
 230 {
 231         int ret;
 232         u16 total_len;
 233
 234         mcp->txbuf[0] = type;
 235         if (msg) {
 236                 mcp->txbuf[1] = msg->len & 0xff;
 237                 mcp->txbuf[2] = msg->len >> 8;
 238                 mcp->txbuf[3] = (u8)(msg->addr << 1);
 239                 total_len = msg->len;
 240                 mcp->rxbuf = msg->buf;
 241         } else {
 242                 mcp->txbuf[1] = smbus_len;
 243                 mcp->txbuf[2] = 0;
 244                 mcp->txbuf[3] = (u8)(smbus_addr << 1);
 245                 total_len = smbus_len;
 246                 mcp->rxbuf = smbus_buf;
 247         }
 248
 249         ret = mcp_send_data_req_status(mcp, mcp->txbuf, 4);
 250         if (ret)
 251                 return ret;
 252
 253         mcp->rxbuf_idx = 0;
 254
 255         do {
 256                 memset(mcp->txbuf, 0, 4);
 257                 mcp->txbuf[0] = MCP2221_I2C_GET_DATA;
 258
 259                 ret = mcp_send_data_req_status(mcp, mcp->txbuf, 1);
 260                 if (ret)
 261                         return ret;
 262
 263                 ret = mcp_chk_last_cmd_status(mcp);
 264                 if (ret)
 265                         return ret;
 266
 267                 usleep_range(980, 1000);
 268         } while (mcp->rxbuf_idx < total_len);
 269
 270         return ret;
 271 }
 272
 273 static int mcp_i2c_xfer(struct i2c_adapter *adapter,
 274                                 struct i2c_msg msgs[], int num)
 275 {
 276         int ret;
 277         struct mcp2221 *mcp = i2c_get_adapdata(adapter);
 278
 279         hid_hw_power(mcp->hdev, PM_HINT_FULLON);
 280
 281         mutex_lock(&mcp->lock);
 282
 283         /* Setting speed before every transaction is required for mcp2221 */
 284         ret = mcp_set_i2c_speed(mcp);
 285         if (ret)
 286                 goto exit;
 287
 288         if (num == 1) {
 289                 if (msgs->flags & I2C_M_RD) {
 290                         ret = mcp_i2c_smbus_read(mcp, msgs, MCP2221_I2C_RD_DATA,
 291                                                         0, 0, NULL);
 292                 } else {
 293                         ret = mcp_i2c_write(mcp, msgs, MCP2221_I2C_WR_DATA, 1);
 294                 }
 295                 if (ret)
 296                         goto exit;
 297                 ret = num;
 298         } else if (num == 2) {
 299                 /* Ex transaction; send reg address and read its contents */
 300                 if (msgs[0].addr == msgs[1].addr &&
 301                         !(msgs[0].flags & I2C_M_RD) &&
 302                          (msgs[1].flags & I2C_M_RD)) {
 303
 304                         ret = mcp_i2c_write(mcp, &msgs[0],
 305                                                 MCP2221_I2C_WR_NO_STOP, 0);
 306                         if (ret)
 307                                 goto exit;
 308
 309                         ret = mcp_i2c_smbus_read(mcp, &msgs[1],
 310                                                 MCP2221_I2C_RD_RPT_START,
 311                                                 0, 0, NULL);
 312                         if (ret)
 313                                 goto exit;
 314                         ret = num;
 315                 } else {
 316                         dev_err(&adapter->dev,
 317                                 "unsupported multi-msg i2c transaction\n");
 318                         ret = -EOPNOTSUPP;
 319                 }
 320         } else {
 321                 dev_err(&adapter->dev,
 322                         "unsupported multi-msg i2c transaction\n");
 323                 ret = -EOPNOTSUPP;
 324         }
 325
 326 exit:
 327         hid_hw_power(mcp->hdev, PM_HINT_NORMAL);
 328         mutex_unlock(&mcp->lock);
 329         return ret;
 330 }
 331
 332 static int mcp_smbus_write(struct mcp2221 *mcp, u16 addr,
 333                                 u8 command, u8 *buf, u8 len, int type,
 334                                 u8 last_status)
 335 {
 336         int data_len, ret;
 337
 338         mcp->txbuf[0] = type;
 339         mcp->txbuf[1] = len + 1; /* 1 is due to command byte itself */
 340         mcp->txbuf[2] = 0;
 341         mcp->txbuf[3] = (u8)(addr << 1);
 342         mcp->txbuf[4] = command;
 343
 344         switch (len) {
 345         case 0:
 346                 data_len = 5;
 347                 break;
 348         case 1:
 349                 mcp->txbuf[5] = buf[0];
 350                 data_len = 6;
 351                 break;
 352         case 2:
 353                 mcp->txbuf[5] = buf[0];
 354                 mcp->txbuf[6] = buf[1];
 355                 data_len = 7;
 356                 break;
 357         default:
 358                 memcpy(&mcp->txbuf[5], buf, len);
 359                 data_len = len + 5;
 360         }
 361
 362         ret = mcp_send_data_req_status(mcp, mcp->txbuf, data_len);
 363         if (ret)
 364                 return ret;
 365
 366         if (last_status) {
 367                 usleep_range(980, 1000);
 368
 369                 ret = mcp_chk_last_cmd_status(mcp);
 370                 if (ret)
 371                         return ret;
 372         }
 373
 374         return ret;
 375 }
 376
 377 static int mcp_smbus_xfer(struct i2c_adapter *adapter, u16 addr,
 378                                 unsigned short flags, char read_write,
 379                                 u8 command, int size,
 380                                 union i2c_smbus_data *data)
 381 {
 382         int ret;
 383         struct mcp2221 *mcp = i2c_get_adapdata(adapter);
 384
 385         hid_hw_power(mcp->hdev, PM_HINT_FULLON);
 386
 387         mutex_lock(&mcp->lock);
 388
 389         ret = mcp_set_i2c_speed(mcp);
 390         if (ret)
 391                 goto exit;
 392
 393         switch (size) {
 394
 395         case I2C_SMBUS_QUICK:
 396                 if (read_write == I2C_SMBUS_READ)
 397                         ret = mcp_i2c_smbus_read(mcp, NULL, MCP2221_I2C_RD_DATA,
 398                                                 addr, 0, &data->byte);
 399                 else
 400                         ret = mcp_smbus_write(mcp, addr, command, NULL,
 401                                                 0, MCP2221_I2C_WR_DATA, 1);
 402                 break;
 403         case I2C_SMBUS_BYTE:
 404                 if (read_write == I2C_SMBUS_READ)
 405                         ret = mcp_i2c_smbus_read(mcp, NULL, MCP2221_I2C_RD_DATA,
 406                                                 addr, 1, &data->byte);
 407                 else
 408                         ret = mcp_smbus_write(mcp, addr, command, NULL,
 409                                                 0, MCP2221_I2C_WR_DATA, 1);
 410                 break;
 411         case I2C_SMBUS_BYTE_DATA:
 412                 if (read_write == I2C_SMBUS_READ) {
 413                         ret = mcp_smbus_write(mcp, addr, command, NULL,
 414                                                 0, MCP2221_I2C_WR_NO_STOP, 0);
 415                         if (ret)
 416                                 goto exit;
 417
 418                         ret = mcp_i2c_smbus_read(mcp, NULL,
 419                                                 MCP2221_I2C_RD_RPT_START,
 420                                                 addr, 1, &data->byte);
 421                 } else {
 422                         ret = mcp_smbus_write(mcp, addr, command, &data->byte,
 423                                                 1, MCP2221_I2C_WR_DATA, 1);
 424                 }
 425                 break;
 426         case I2C_SMBUS_WORD_DATA:
 427                 if (read_write == I2C_SMBUS_READ) {
 428                         ret = mcp_smbus_write(mcp, addr, command, NULL,
 429                                                 0, MCP2221_I2C_WR_NO_STOP, 0);
 430                         if (ret)
 431                                 goto exit;
 432
 433                         ret = mcp_i2c_smbus_read(mcp, NULL,
 434                                                 MCP2221_I2C_RD_RPT_START,
 435                                                 addr, 2, (u8 *)&data->word);
 436                 } else {
 437                         ret = mcp_smbus_write(mcp, addr, command,
 438                                                 (u8 *)&data->word, 2,
 439                                                 MCP2221_I2C_WR_DATA, 1);
 440                 }
 441                 break;
 442         case I2C_SMBUS_BLOCK_DATA:
 443                 if (read_write == I2C_SMBUS_READ) {
 444                         ret = mcp_smbus_write(mcp, addr, command, NULL,
 445                                                 0, MCP2221_I2C_WR_NO_STOP, 1);
 446                         if (ret)
 447                                 goto exit;
 448
 449                         mcp->rxbuf_idx = 0;
 450                         mcp->rxbuf = data->block;
 451                         mcp->txbuf[0] = MCP2221_I2C_GET_DATA;
 452                         ret = mcp_send_data_req_status(mcp, mcp->txbuf, 1);
 453                         if (ret)
 454                                 goto exit;
 455                 } else {
 456                         if (!data->block[0]) {
 457                                 ret = -EINVAL;
 458                                 goto exit;
 459                         }
 460                         ret = mcp_smbus_write(mcp, addr, command, data->block,
 461                                                 data->block[0] + 1,
 462                                                 MCP2221_I2C_WR_DATA, 1);
 463                 }
 464                 break;
 465         case I2C_SMBUS_I2C_BLOCK_DATA:
 466                 if (read_write == I2C_SMBUS_READ) {
 467                         ret = mcp_smbus_write(mcp, addr, command, NULL,
 468                                                 0, MCP2221_I2C_WR_NO_STOP, 1);
 469                         if (ret)
 470                                 goto exit;
 471
 472                         mcp->rxbuf_idx = 0;
 473                         mcp->rxbuf = data->block;
 474                         mcp->txbuf[0] = MCP2221_I2C_GET_DATA;
 475                         ret = mcp_send_data_req_status(mcp, mcp->txbuf, 1);
 476                         if (ret)
 477                                 goto exit;
 478                 } else {
 479                         if (!data->block[0]) {
 480                                 ret = -EINVAL;
 481                                 goto exit;
 482                         }
 483                         ret = mcp_smbus_write(mcp, addr, command,
 484                                                 &data->block[1], data->block[0],
 485                                                 MCP2221_I2C_WR_DATA, 1);
 486                 }
 487                 break;
 488         case I2C_SMBUS_PROC_CALL:
 489                 ret = mcp_smbus_write(mcp, addr, command,
 490                                                 (u8 *)&data->word,
 491                                                 2, MCP2221_I2C_WR_NO_STOP, 0);
 492                 if (ret)
 493                         goto exit;
 494
 495                 ret = mcp_i2c_smbus_read(mcp, NULL,
 496                                                 MCP2221_I2C_RD_RPT_START,
 497                                                 addr, 2, (u8 *)&data->word);
 498                 break;
 499         case I2C_SMBUS_BLOCK_PROC_CALL:
 500                 ret = mcp_smbus_write(mcp, addr, command, data->block,
 501                                                 data->block[0] + 1,
 502                                                 MCP2221_I2C_WR_NO_STOP, 0);
 503                 if (ret)
 504                         goto exit;
 505
 506                 ret = mcp_i2c_smbus_read(mcp, NULL,
 507                                                 MCP2221_I2C_RD_RPT_START,
 508                                                 addr, I2C_SMBUS_BLOCK_MAX,
 509                                                 data->block);
 510                 break;
 511         default:
 512                 dev_err(&mcp->adapter.dev,
 513                         "unsupported smbus transaction size:%d\n", size);
 514                 ret = -EOPNOTSUPP;
 515         }
 516
 517 exit:
 518         hid_hw_power(mcp->hdev, PM_HINT_NORMAL);
 519         mutex_unlock(&mcp->lock);
 520         return ret;
 521 }
 522
 523 static u32 mcp_i2c_func(struct i2c_adapter *adapter)
 524 {
 525         return I2C_FUNC_I2C |
 526                         I2C_FUNC_SMBUS_READ_BLOCK_DATA |
 527                         I2C_FUNC_SMBUS_BLOCK_PROC_CALL |
 528                         (I2C_FUNC_SMBUS_EMUL & ~I2C_FUNC_SMBUS_PEC);
 529 }
 530
 531 static const struct i2c_algorithm mcp_i2c_algo = {
 532         .master_xfer = mcp_i2c_xfer,
 533         .smbus_xfer = mcp_smbus_xfer,
 534         .functionality = mcp_i2c_func,
 535 };
 536
 537 static int mcp_gpio_get(struct gpio_chip *gc,
 538                                 unsigned int offset)
 539 {
 540         int ret;
 541         struct mcp2221 *mcp = gpiochip_get_data(gc);
 542
 543         mcp->txbuf[0] = MCP2221_GPIO_GET;
 544
 545         mcp->gp_idx = (offset + 1) * 2;
 546
 547         mutex_lock(&mcp->lock);
 548         ret = mcp_send_data_req_status(mcp, mcp->txbuf, 1);
 549         mutex_unlock(&mcp->lock);
 550
 551         return ret;
 552 }
 553
 554 static void mcp_gpio_set(struct gpio_chip *gc,
 555                                 unsigned int offset, int value)
 556 {
 557         struct mcp2221 *mcp = gpiochip_get_data(gc);
 558
 559         memset(mcp->txbuf, 0, 18);
 560         mcp->txbuf[0] = MCP2221_GPIO_SET;
 561
 562         mcp->gp_idx = ((offset + 1) * 4) - 1;
 563
 564         mcp->txbuf[mcp->gp_idx - 1] = 1;
 565         mcp->txbuf[mcp->gp_idx] = !!value;
 566
 567         mutex_lock(&mcp->lock);
 568         mcp_send_data_req_status(mcp, mcp->txbuf, 18);
 569         mutex_unlock(&mcp->lock);
 570 }
 571
 572 static int mcp_gpio_dir_set(struct mcp2221 *mcp,
 573                                 unsigned int offset, u8 val)
 574 {
 575         memset(mcp->txbuf, 0, 18);
 576         mcp->txbuf[0] = MCP2221_GPIO_SET;
 577
 578         mcp->gp_idx = (offset + 1) * 5;
 579
 580         mcp->txbuf[mcp->gp_idx - 1] = 1;
 581         mcp->txbuf[mcp->gp_idx] = val;
 582
 583         return mcp_send_data_req_status(mcp, mcp->txbuf, 18);
 584 }
 585
 586 static int mcp_gpio_direction_input(struct gpio_chip *gc,
 587                                 unsigned int offset)
 588 {
 589         int ret;
 590         struct mcp2221 *mcp = gpiochip_get_data(gc);
 591
 592         mutex_lock(&mcp->lock);
 593         ret = mcp_gpio_dir_set(mcp, offset, 0);
 594         mutex_unlock(&mcp->lock);
 595
 596         return ret;
 597 }
 598
 599 static int mcp_gpio_direction_output(struct gpio_chip *gc,
 600                                 unsigned int offset, int value)
 601 {
 602         int ret;
 603         struct mcp2221 *mcp = gpiochip_get_data(gc);
 604
 605         mutex_lock(&mcp->lock);
 606         ret = mcp_gpio_dir_set(mcp, offset, 1);
 607         mutex_unlock(&mcp->lock);
 608
 609         /* Can't configure as output, bailout early */
 610         if (ret)
 611                 return ret;
 612
 613         mcp_gpio_set(gc, offset, value);
 614
 615         return 0;
 616 }
 617
 618 static int mcp_gpio_get_direction(struct gpio_chip *gc,
 619                                 unsigned int offset)
 620 {
 621         int ret;
 622         struct mcp2221 *mcp = gpiochip_get_data(gc);
 623
 624         mcp->txbuf[0] = MCP2221_GPIO_GET;
 625
 626         mcp->gp_idx = (offset + 1) * 2;
 627
 628         mutex_lock(&mcp->lock);
 629         ret = mcp_send_data_req_status(mcp, mcp->txbuf, 1);
 630         mutex_unlock(&mcp->lock);
 631
 632         if (ret)
 633                 return ret;
 634
 635         if (mcp->gpio_dir)
 636                 return GPIO_LINE_DIRECTION_IN;
 637
 638         return GPIO_LINE_DIRECTION_OUT;
 639 }
 640
 641 /* Gives current state of i2c engine inside mcp2221 */
 642 static int mcp_get_i2c_eng_state(struct mcp2221 *mcp,
 643                                 u8 *data, u8 idx)
 644 {
 645         int ret;
 646
 647         switch (data[idx]) {
 648         case MCP2221_I2C_WRADDRL_NACK:
 649         case MCP2221_I2C_WRADDRL_SEND:
 650                 ret = -ENXIO;
 651                 break;
 652         case MCP2221_I2C_START_TOUT:
 653         case MCP2221_I2C_STOP_TOUT:
 654         case MCP2221_I2C_WRADDRL_TOUT:
 655         case MCP2221_I2C_WRDATA_TOUT:
 656                 ret = -ETIMEDOUT;
 657                 break;
 658         case MCP2221_I2C_ENG_BUSY:
 659                 ret = -EAGAIN;
 660                 break;
 661         case MCP2221_SUCCESS:
 662                 ret = 0x00;
 663                 break;
 664         default:
 665                 ret = -EIO;
 666         }
 667
 668         return ret;
 669 }
 670
 671 /*
 672  * MCP2221 uses interrupt endpoint for input reports. This function
 673  * is called by HID layer when it receives i/p report from mcp2221,
 674  * which is actually a response to the previously sent command.
 675  *
 676  * MCP2221A firmware specific return codes are parsed and 0 or
 677  * appropriate negative error code is returned. Delayed response
 678  * results in timeout error and stray reponses results in -EIO.
 679  */
 680 static int mcp2221_raw_event(struct hid_device *hdev,
 681                                 struct hid_report *report, u8 *data, int size)
 682 {
 683         u8 *buf;
 684         struct mcp2221 *mcp = hid_get_drvdata(hdev);
 685
 686         switch (data[0]) {
 687
 688         case MCP2221_I2C_WR_DATA:
 689         case MCP2221_I2C_WR_NO_STOP:
 690         case MCP2221_I2C_RD_DATA:
 691         case MCP2221_I2C_RD_RPT_START:
 692                 switch (data[1]) {
 693                 case MCP2221_SUCCESS:
 694                         mcp->status = 0;
 695                         break;
 696                 default:
 697                         mcp->status = mcp_get_i2c_eng_state(mcp, data, 2);
 698                 }
 699                 complete(&mcp->wait_in_report);
 700                 break;
 701
 702         case MCP2221_I2C_PARAM_OR_STATUS:
 703                 switch (data[1]) {
 704                 case MCP2221_SUCCESS:
 705                         if ((mcp->txbuf[3] == MCP2221_I2C_SET_SPEED) &&
 706                                 (data[3] != MCP2221_I2C_SET_SPEED)) {
 707                                 mcp->status = -EAGAIN;
 708                                 break;
 709                         }
 710                         if (data[20] & MCP2221_I2C_MASK_ADDR_NACK) {
 711                                 mcp->status = -ENXIO;
 712                                 break;
 713                         }
 714                         mcp->status = mcp_get_i2c_eng_state(mcp, data, 8);
 715                         break;
 716                 default:
 717                         mcp->status = -EIO;
 718                 }
 719                 complete(&mcp->wait_in_report);
 720                 break;
 721
 722         case MCP2221_I2C_GET_DATA:
 723                 switch (data[1]) {
 724                 case MCP2221_SUCCESS:
 725                         if (data[2] == MCP2221_I2C_ADDR_NACK) {
 726                                 mcp->status = -ENXIO;
 727                                 break;
 728                         }
 729                         if (!mcp_get_i2c_eng_state(mcp, data, 2)
 730                                 && (data[3] == 0)) {
 731                                 mcp->status = 0;
 732                                 break;
 733                         }
 734                         if (data[3] == 127) {
 735                                 mcp->status = -EIO;
 736                                 break;
 737                         }
 738                         if (data[2] == MCP2221_I2C_READ_COMPL) {
 739                                 buf = mcp->rxbuf;
 740                                 memcpy(&buf[mcp->rxbuf_idx], &data[4], data[3]);
 741                                 mcp->rxbuf_idx = mcp->rxbuf_idx + data[3];
 742                                 mcp->status = 0;
 743                                 break;
 744                         }
 745                         mcp->status = -EIO;
 746                         break;
 747                 default:
 748                         mcp->status = -EIO;
 749                 }
 750                 complete(&mcp->wait_in_report);
 751                 break;
 752
 753         case MCP2221_GPIO_GET:
 754                 switch (data[1]) {
 755                 case MCP2221_SUCCESS:
 756                         if ((data[mcp->gp_idx] == MCP2221_ALT_F_NOT_GPIOV) ||
 757                                 (data[mcp->gp_idx + 1] == MCP2221_ALT_F_NOT_GPIOD)) {
 758                                 mcp->status = -ENOENT;
 759                         } else {
 760                                 mcp->status = !!data[mcp->gp_idx];
 761                                 mcp->gpio_dir = !!data[mcp->gp_idx + 1];
 762                         }
 763                         break;
 764                 default:
 765                         mcp->status = -EAGAIN;
 766                 }
 767                 complete(&mcp->wait_in_report);
 768                 break;
 769
 770         case MCP2221_GPIO_SET:
 771                 switch (data[1]) {
 772                 case MCP2221_SUCCESS:
 773                         if ((data[mcp->gp_idx] == MCP2221_ALT_F_NOT_GPIOV) ||
 774                                 (data[mcp->gp_idx - 1] == MCP2221_ALT_F_NOT_GPIOV)) {
 775                                 mcp->status = -ENOENT;
 776                         } else {
 777                                 mcp->status = 0;
 778                         }
 779                         break;
 780                 default:
 781                         mcp->status = -EAGAIN;
 782                 }
 783                 complete(&mcp->wait_in_report);
 784                 break;
 785
 786         default:
 787                 mcp->status = -EIO;
 788                 complete(&mcp->wait_in_report);
 789         }
 790
 791         return 1;
 792 }
 793
 794 static int mcp2221_probe(struct hid_device *hdev,
 795                                         const struct hid_device_id *id)
 796 {
 797         int ret;
 798         struct mcp2221 *mcp;
 799
 800         mcp = devm_kzalloc(&hdev->dev, sizeof(*mcp), GFP_KERNEL);
 801         if (!mcp)
 802                 return -ENOMEM;
 803
 804         ret = hid_parse(hdev);
 805         if (ret) {
 806                 hid_err(hdev, "can't parse reports\n");
 807                 return ret;
 808         }
 809
 810         ret = hid_hw_start(hdev, HID_CONNECT_HIDRAW);
 811         if (ret) {
 812                 hid_err(hdev, "can't start hardware\n");
 813                 return ret;
 814         }
 815
 816         ret = hid_hw_open(hdev);
 817         if (ret) {
 818                 hid_err(hdev, "can't open device\n");
 819                 goto err_hstop;
 820         }
 821
 822         mutex_init(&mcp->lock);
 823         init_completion(&mcp->wait_in_report);
 824         hid_set_drvdata(hdev, mcp);
 825         mcp->hdev = hdev;
 826
 827         /* Set I2C bus clock diviser */
 828         if (i2c_clk_freq > 400)
 829                 i2c_clk_freq = 400;
 830         if (i2c_clk_freq < 50)
 831                 i2c_clk_freq = 50;
 832         mcp->cur_i2c_clk_div = (12000000 / (i2c_clk_freq * 1000)) - 3;
 833
 834         mcp->adapter.owner = THIS_MODULE;
 835         mcp->adapter.class = I2C_CLASS_HWMON;
 836         mcp->adapter.algo = &mcp_i2c_algo;
 837         mcp->adapter.retries = 1;
 838         mcp->adapter.dev.parent = &hdev->dev;
 839         snprintf(mcp->adapter.name, sizeof(mcp->adapter.name),
 840                         "MCP2221 usb-i2c bridge on hidraw%d",
 841                         ((struct hidraw *)hdev->hidraw)->minor);
 842
 843         ret = i2c_add_adapter(&mcp->adapter);
 844         if (ret) {
 845                 hid_err(hdev, "can't add usb-i2c adapter: %d\n", ret);
 846                 goto err_i2c;
 847         }
 848         i2c_set_adapdata(&mcp->adapter, mcp);
 849
 850         /* Setup GPIO chip */
 851         mcp->gc = devm_kzalloc(&hdev->dev, sizeof(*mcp->gc), GFP_KERNEL);
 852         if (!mcp->gc) {
 853                 ret = -ENOMEM;
 854                 goto err_gc;
 855         }
 856
 857         mcp->gc->label = "mcp2221_gpio";
 858         mcp->gc->direction_input = mcp_gpio_direction_input;
 859         mcp->gc->direction_output = mcp_gpio_direction_output;
 860         mcp->gc->get_direction = mcp_gpio_get_direction;
 861         mcp->gc->set = mcp_gpio_set;
 862         mcp->gc->get = mcp_gpio_get;
 863         mcp->gc->ngpio = 4;
 864         mcp->gc->base = -1;
 865         mcp->gc->can_sleep = 1;
 866         mcp->gc->parent = &hdev->dev;
 867
 868         ret = devm_gpiochip_add_data(&hdev->dev, mcp->gc, mcp);
 869         if (ret)
 870                 goto err_gc;
 871
 872         return 0;
 873
 874 err_gc:
 875         i2c_del_adapter(&mcp->adapter);
 876 err_i2c:
 877         hid_hw_close(mcp->hdev);
 878 err_hstop:
 879         hid_hw_stop(mcp->hdev);
 880         return ret;
 881 }
 882
 883 static void mcp2221_remove(struct hid_device *hdev)
 884 {
 885         struct mcp2221 *mcp = hid_get_drvdata(hdev);
 886
 887         i2c_del_adapter(&mcp->adapter);
 888         hid_hw_close(mcp->hdev);
 889         hid_hw_stop(mcp->hdev);
 890 }
 891
 892 static const struct hid_device_id mcp2221_devices[] = {
 893         { HID_USB_DEVICE(USB_VENDOR_ID_MICROCHIP, USB_DEVICE_ID_MCP2221) },
 894         { }
 895 };
 896 MODULE_DEVICE_TABLE(hid, mcp2221_devices);
 897
 898 static struct hid_driver mcp2221_driver = {
 899         .name           = "mcp2221",
 900         .id_table       = mcp2221_devices,
 901         .probe          = mcp2221_probe,
 902         .remove         = mcp2221_remove,
 903         .raw_event      = mcp2221_raw_event,
 904 };
 905
 906 /* Register with HID core */
 907 module_hid_driver(mcp2221_driver);
 908
 909 MODULE_AUTHOR("Rishi Gupta <gupt21@gmail.com>");
 910 MODULE_DESCRIPTION("MCP2221 Microchip HID USB to I2C master bridge");
 911 MODULE_LICENSE("GPL v2");