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 /* MCP GPIO direction encoding */
  53 enum {
  54         MCP2221_DIR_OUT = 0x00,
  55         MCP2221_DIR_IN = 0x01,
  56 };
  57
  58 #define MCP_NGPIO       4
  59
  60 /* MCP GPIO set command layout */
  61 struct mcp_set_gpio {
  62         u8 cmd;
  63         u8 dummy;
  64         struct {
  65                 u8 change_value;
  66                 u8 value;
  67                 u8 change_direction;
  68                 u8 direction;
  69         } gpio[MCP_NGPIO];
  70 } __packed;
  71
  72 /* MCP GPIO get command layout */
  73 struct mcp_get_gpio {
  74         u8 cmd;
  75         u8 dummy;
  76         struct {
  77                 u8 direction;
  78                 u8 value;
  79         } gpio[MCP_NGPIO];
  80 } __packed;
  81
  82 /*
  83  * There is no way to distinguish responses. Therefore next command
  84  * is sent only after response to previous has been received. Mutex
  85  * lock is used for this purpose mainly.
  86  */
  87 struct mcp2221 {
  88         struct hid_device *hdev;
  89         struct i2c_adapter adapter;
  90         struct mutex lock;
  91         struct completion wait_in_report;
  92         u8 *rxbuf;
  93         u8 txbuf[64];
  94         int rxbuf_idx;
  95         int status;
  96         u8 cur_i2c_clk_div;
  97         struct gpio_chip *gc;
  98         u8 gp_idx;
  99         u8 gpio_dir;
 100 };
 101
 102 /*
 103  * Default i2c bus clock frequency 400 kHz. Modify this if you
 104  * want to set some other frequency (min 50 kHz - max 400 kHz).
 105  */
 106 static uint i2c_clk_freq = 400;
 107
 108 /* Synchronously send output report to the device */
 109 static int mcp_send_report(struct mcp2221 *mcp,
 110                                         u8 *out_report, size_t len)
 111 {
 112         u8 *buf;
 113         int ret;
 114
 115         buf = kmemdup(out_report, len, GFP_KERNEL);
 116         if (!buf)
 117                 return -ENOMEM;
 118
 119         /* mcp2221 uses interrupt endpoint for out reports */
 120         ret = hid_hw_output_report(mcp->hdev, buf, len);
 121         kfree(buf);
 122
 123         if (ret < 0)
 124                 return ret;
 125         return 0;
 126 }
 127
 128 /*
 129  * Send o/p report to the device and wait for i/p report to be
 130  * received from the device. If the device does not respond,
 131  * we timeout.
 132  */
 133 static int mcp_send_data_req_status(struct mcp2221 *mcp,
 134                         u8 *out_report, int len)
 135 {
 136         int ret;
 137         unsigned long t;
 138
 139         reinit_completion(&mcp->wait_in_report);
 140
 141         ret = mcp_send_report(mcp, out_report, len);
 142         if (ret)
 143                 return ret;
 144
 145         t = wait_for_completion_timeout(&mcp->wait_in_report,
 146                                                         msecs_to_jiffies(4000));
 147         if (!t)
 148                 return -ETIMEDOUT;
 149
 150         return mcp->status;
 151 }
 152
 153 /* Check pass/fail for actual communication with i2c slave */
 154 static int mcp_chk_last_cmd_status(struct mcp2221 *mcp)
 155 {
 156         memset(mcp->txbuf, 0, 8);
 157         mcp->txbuf[0] = MCP2221_I2C_PARAM_OR_STATUS;
 158
 159         return mcp_send_data_req_status(mcp, mcp->txbuf, 8);
 160 }
 161
 162 /* Cancels last command releasing i2c bus just in case occupied */
 163 static int mcp_cancel_last_cmd(struct mcp2221 *mcp)
 164 {
 165         memset(mcp->txbuf, 0, 8);
 166         mcp->txbuf[0] = MCP2221_I2C_PARAM_OR_STATUS;
 167         mcp->txbuf[2] = MCP2221_I2C_CANCEL;
 168
 169         return mcp_send_data_req_status(mcp, mcp->txbuf, 8);
 170 }
 171
 172 static int mcp_set_i2c_speed(struct mcp2221 *mcp)
 173 {
 174         int ret;
 175
 176         memset(mcp->txbuf, 0, 8);
 177         mcp->txbuf[0] = MCP2221_I2C_PARAM_OR_STATUS;
 178         mcp->txbuf[3] = MCP2221_I2C_SET_SPEED;
 179         mcp->txbuf[4] = mcp->cur_i2c_clk_div;
 180
 181         ret = mcp_send_data_req_status(mcp, mcp->txbuf, 8);
 182         if (ret) {
 183                 /* Small delay is needed here */
 184                 usleep_range(980, 1000);
 185                 mcp_cancel_last_cmd(mcp);
 186         }
 187
 188         return 0;
 189 }
 190
 191 /*
 192  * An output report can contain minimum 1 and maximum 60 user data
 193  * bytes. If the number of data bytes is more then 60, we send it
 194  * in chunks of 60 bytes. Last chunk may contain exactly 60 or less
 195  * bytes. Total number of bytes is informed in very first report to
 196  * mcp2221, from that point onwards it first collect all the data
 197  * from host and then send to i2c slave device.
 198  */
 199 static int mcp_i2c_write(struct mcp2221 *mcp,
 200                                 struct i2c_msg *msg, int type, u8 last_status)
 201 {
 202         int ret, len, idx, sent;
 203
 204         idx = 0;
 205         sent  = 0;
 206         if (msg->len < 60)
 207                 len = msg->len;
 208         else
 209                 len = 60;
 210
 211         do {
 212                 mcp->txbuf[0] = type;
 213                 mcp->txbuf[1] = msg->len & 0xff;
 214                 mcp->txbuf[2] = msg->len >> 8;
 215                 mcp->txbuf[3] = (u8)(msg->addr << 1);
 216
 217                 memcpy(&mcp->txbuf[4], &msg->buf[idx], len);
 218
 219                 ret = mcp_send_data_req_status(mcp, mcp->txbuf, len + 4);
 220                 if (ret)
 221                         return ret;
 222
 223                 usleep_range(980, 1000);
 224
 225                 if (last_status) {
 226                         ret = mcp_chk_last_cmd_status(mcp);
 227                         if (ret)
 228                                 return ret;
 229                 }
 230
 231                 sent = sent + len;
 232                 if (sent >= msg->len)
 233                         break;
 234
 235                 idx = idx + len;
 236                 if ((msg->len - sent) < 60)
 237                         len = msg->len - sent;
 238                 else
 239                         len = 60;
 240
 241                 /*
 242                  * Testing shows delay is needed between successive writes
 243                  * otherwise next write fails on first-try from i2c core.
 244                  * This value is obtained through automated stress testing.
 245                  */
 246                 usleep_range(980, 1000);
 247         } while (len > 0);
 248
 249         return ret;
 250 }
 251
 252 /*
 253  * Device reads all data (0 - 65535 bytes) from i2c slave device and
 254  * stores it in device itself. This data is read back from device to
 255  * host in multiples of 60 bytes using input reports.
 256  */
 257 static int mcp_i2c_smbus_read(struct mcp2221 *mcp,
 258                                 struct i2c_msg *msg, int type, u16 smbus_addr,
 259                                 u8 smbus_len, u8 *smbus_buf)
 260 {
 261         int ret;
 262         u16 total_len;
 263
 264         mcp->txbuf[0] = type;
 265         if (msg) {
 266                 mcp->txbuf[1] = msg->len & 0xff;
 267                 mcp->txbuf[2] = msg->len >> 8;
 268                 mcp->txbuf[3] = (u8)(msg->addr << 1);
 269                 total_len = msg->len;
 270                 mcp->rxbuf = msg->buf;
 271         } else {
 272                 mcp->txbuf[1] = smbus_len;
 273                 mcp->txbuf[2] = 0;
 274                 mcp->txbuf[3] = (u8)(smbus_addr << 1);
 275                 total_len = smbus_len;
 276                 mcp->rxbuf = smbus_buf;
 277         }
 278
 279         ret = mcp_send_data_req_status(mcp, mcp->txbuf, 4);
 280         if (ret)
 281                 return ret;
 282
 283         mcp->rxbuf_idx = 0;
 284
 285         do {
 286                 memset(mcp->txbuf, 0, 4);
 287                 mcp->txbuf[0] = MCP2221_I2C_GET_DATA;
 288
 289                 ret = mcp_send_data_req_status(mcp, mcp->txbuf, 1);
 290                 if (ret)
 291                         return ret;
 292
 293                 ret = mcp_chk_last_cmd_status(mcp);
 294                 if (ret)
 295                         return ret;
 296
 297                 usleep_range(980, 1000);
 298         } while (mcp->rxbuf_idx < total_len);
 299
 300         return ret;
 301 }
 302
 303 static int mcp_i2c_xfer(struct i2c_adapter *adapter,
 304                                 struct i2c_msg msgs[], int num)
 305 {
 306         int ret;
 307         struct mcp2221 *mcp = i2c_get_adapdata(adapter);
 308
 309         hid_hw_power(mcp->hdev, PM_HINT_FULLON);
 310
 311         mutex_lock(&mcp->lock);
 312
 313         /* Setting speed before every transaction is required for mcp2221 */
 314         ret = mcp_set_i2c_speed(mcp);
 315         if (ret)
 316                 goto exit;
 317
 318         if (num == 1) {
 319                 if (msgs->flags & I2C_M_RD) {
 320                         ret = mcp_i2c_smbus_read(mcp, msgs, MCP2221_I2C_RD_DATA,
 321                                                         0, 0, NULL);
 322                 } else {
 323                         ret = mcp_i2c_write(mcp, msgs, MCP2221_I2C_WR_DATA, 1);
 324                 }
 325                 if (ret)
 326                         goto exit;
 327                 ret = num;
 328         } else if (num == 2) {
 329                 /* Ex transaction; send reg address and read its contents */
 330                 if (msgs[0].addr == msgs[1].addr &&
 331                         !(msgs[0].flags & I2C_M_RD) &&
 332                          (msgs[1].flags & I2C_M_RD)) {
 333
 334                         ret = mcp_i2c_write(mcp, &msgs[0],
 335                                                 MCP2221_I2C_WR_NO_STOP, 0);
 336                         if (ret)
 337                                 goto exit;
 338
 339                         ret = mcp_i2c_smbus_read(mcp, &msgs[1],
 340                                                 MCP2221_I2C_RD_RPT_START,
 341                                                 0, 0, NULL);
 342                         if (ret)
 343                                 goto exit;
 344                         ret = num;
 345                 } else {
 346                         dev_err(&adapter->dev,
 347                                 "unsupported multi-msg i2c transaction\n");
 348                         ret = -EOPNOTSUPP;
 349                 }
 350         } else {
 351                 dev_err(&adapter->dev,
 352                         "unsupported multi-msg i2c transaction\n");
 353                 ret = -EOPNOTSUPP;
 354         }
 355
 356 exit:
 357         hid_hw_power(mcp->hdev, PM_HINT_NORMAL);
 358         mutex_unlock(&mcp->lock);
 359         return ret;
 360 }
 361
 362 static int mcp_smbus_write(struct mcp2221 *mcp, u16 addr,
 363                                 u8 command, u8 *buf, u8 len, int type,
 364                                 u8 last_status)
 365 {
 366         int data_len, ret;
 367
 368         mcp->txbuf[0] = type;
 369         mcp->txbuf[1] = len + 1; /* 1 is due to command byte itself */
 370         mcp->txbuf[2] = 0;
 371         mcp->txbuf[3] = (u8)(addr << 1);
 372         mcp->txbuf[4] = command;
 373
 374         switch (len) {
 375         case 0:
 376                 data_len = 5;
 377                 break;
 378         case 1:
 379                 mcp->txbuf[5] = buf[0];
 380                 data_len = 6;
 381                 break;
 382         case 2:
 383                 mcp->txbuf[5] = buf[0];
 384                 mcp->txbuf[6] = buf[1];
 385                 data_len = 7;
 386                 break;
 387         default:
 388                 memcpy(&mcp->txbuf[5], buf, len);
 389                 data_len = len + 5;
 390         }
 391
 392         ret = mcp_send_data_req_status(mcp, mcp->txbuf, data_len);
 393         if (ret)
 394                 return ret;
 395
 396         if (last_status) {
 397                 usleep_range(980, 1000);
 398
 399                 ret = mcp_chk_last_cmd_status(mcp);
 400                 if (ret)
 401                         return ret;
 402         }
 403
 404         return ret;
 405 }
 406
 407 static int mcp_smbus_xfer(struct i2c_adapter *adapter, u16 addr,
 408                                 unsigned short flags, char read_write,
 409                                 u8 command, int size,
 410                                 union i2c_smbus_data *data)
 411 {
 412         int ret;
 413         struct mcp2221 *mcp = i2c_get_adapdata(adapter);
 414
 415         hid_hw_power(mcp->hdev, PM_HINT_FULLON);
 416
 417         mutex_lock(&mcp->lock);
 418
 419         ret = mcp_set_i2c_speed(mcp);
 420         if (ret)
 421                 goto exit;
 422
 423         switch (size) {
 424
 425         case I2C_SMBUS_QUICK:
 426                 if (read_write == I2C_SMBUS_READ)
 427                         ret = mcp_i2c_smbus_read(mcp, NULL, MCP2221_I2C_RD_DATA,
 428                                                 addr, 0, &data->byte);
 429                 else
 430                         ret = mcp_smbus_write(mcp, addr, command, NULL,
 431                                                 0, MCP2221_I2C_WR_DATA, 1);
 432                 break;
 433         case I2C_SMBUS_BYTE:
 434                 if (read_write == I2C_SMBUS_READ)
 435                         ret = mcp_i2c_smbus_read(mcp, NULL, MCP2221_I2C_RD_DATA,
 436                                                 addr, 1, &data->byte);
 437                 else
 438                         ret = mcp_smbus_write(mcp, addr, command, NULL,
 439                                                 0, MCP2221_I2C_WR_DATA, 1);
 440                 break;
 441         case I2C_SMBUS_BYTE_DATA:
 442                 if (read_write == I2C_SMBUS_READ) {
 443                         ret = mcp_smbus_write(mcp, addr, command, NULL,
 444                                                 0, MCP2221_I2C_WR_NO_STOP, 0);
 445                         if (ret)
 446                                 goto exit;
 447
 448                         ret = mcp_i2c_smbus_read(mcp, NULL,
 449                                                 MCP2221_I2C_RD_RPT_START,
 450                                                 addr, 1, &data->byte);
 451                 } else {
 452                         ret = mcp_smbus_write(mcp, addr, command, &data->byte,
 453                                                 1, MCP2221_I2C_WR_DATA, 1);
 454                 }
 455                 break;
 456         case I2C_SMBUS_WORD_DATA:
 457                 if (read_write == I2C_SMBUS_READ) {
 458                         ret = mcp_smbus_write(mcp, addr, command, NULL,
 459                                                 0, MCP2221_I2C_WR_NO_STOP, 0);
 460                         if (ret)
 461                                 goto exit;
 462
 463                         ret = mcp_i2c_smbus_read(mcp, NULL,
 464                                                 MCP2221_I2C_RD_RPT_START,
 465                                                 addr, 2, (u8 *)&data->word);
 466                 } else {
 467                         ret = mcp_smbus_write(mcp, addr, command,
 468                                                 (u8 *)&data->word, 2,
 469                                                 MCP2221_I2C_WR_DATA, 1);
 470                 }
 471                 break;
 472         case I2C_SMBUS_BLOCK_DATA:
 473                 if (read_write == I2C_SMBUS_READ) {
 474                         ret = mcp_smbus_write(mcp, addr, command, NULL,
 475                                                 0, MCP2221_I2C_WR_NO_STOP, 1);
 476                         if (ret)
 477                                 goto exit;
 478
 479                         mcp->rxbuf_idx = 0;
 480                         mcp->rxbuf = data->block;
 481                         mcp->txbuf[0] = MCP2221_I2C_GET_DATA;
 482                         ret = mcp_send_data_req_status(mcp, mcp->txbuf, 1);
 483                         if (ret)
 484                                 goto exit;
 485                 } else {
 486                         if (!data->block[0]) {
 487                                 ret = -EINVAL;
 488                                 goto exit;
 489                         }
 490                         ret = mcp_smbus_write(mcp, addr, command, data->block,
 491                                                 data->block[0] + 1,
 492                                                 MCP2221_I2C_WR_DATA, 1);
 493                 }
 494                 break;
 495         case I2C_SMBUS_I2C_BLOCK_DATA:
 496                 if (read_write == I2C_SMBUS_READ) {
 497                         ret = mcp_smbus_write(mcp, addr, command, NULL,
 498                                                 0, MCP2221_I2C_WR_NO_STOP, 1);
 499                         if (ret)
 500                                 goto exit;
 501
 502                         mcp->rxbuf_idx = 0;
 503                         mcp->rxbuf = data->block;
 504                         mcp->txbuf[0] = MCP2221_I2C_GET_DATA;
 505                         ret = mcp_send_data_req_status(mcp, mcp->txbuf, 1);
 506                         if (ret)
 507                                 goto exit;
 508                 } else {
 509                         if (!data->block[0]) {
 510                                 ret = -EINVAL;
 511                                 goto exit;
 512                         }
 513                         ret = mcp_smbus_write(mcp, addr, command,
 514                                                 &data->block[1], data->block[0],
 515                                                 MCP2221_I2C_WR_DATA, 1);
 516                 }
 517                 break;
 518         case I2C_SMBUS_PROC_CALL:
 519                 ret = mcp_smbus_write(mcp, addr, command,
 520                                                 (u8 *)&data->word,
 521                                                 2, MCP2221_I2C_WR_NO_STOP, 0);
 522                 if (ret)
 523                         goto exit;
 524
 525                 ret = mcp_i2c_smbus_read(mcp, NULL,
 526                                                 MCP2221_I2C_RD_RPT_START,
 527                                                 addr, 2, (u8 *)&data->word);
 528                 break;
 529         case I2C_SMBUS_BLOCK_PROC_CALL:
 530                 ret = mcp_smbus_write(mcp, addr, command, data->block,
 531                                                 data->block[0] + 1,
 532                                                 MCP2221_I2C_WR_NO_STOP, 0);
 533                 if (ret)
 534                         goto exit;
 535
 536                 ret = mcp_i2c_smbus_read(mcp, NULL,
 537                                                 MCP2221_I2C_RD_RPT_START,
 538                                                 addr, I2C_SMBUS_BLOCK_MAX,
 539                                                 data->block);
 540                 break;
 541         default:
 542                 dev_err(&mcp->adapter.dev,
 543                         "unsupported smbus transaction size:%d\n", size);
 544                 ret = -EOPNOTSUPP;
 545         }
 546
 547 exit:
 548         hid_hw_power(mcp->hdev, PM_HINT_NORMAL);
 549         mutex_unlock(&mcp->lock);
 550         return ret;
 551 }
 552
 553 static u32 mcp_i2c_func(struct i2c_adapter *adapter)
 554 {
 555         return I2C_FUNC_I2C |
 556                         I2C_FUNC_SMBUS_READ_BLOCK_DATA |
 557                         I2C_FUNC_SMBUS_BLOCK_PROC_CALL |
 558                         (I2C_FUNC_SMBUS_EMUL & ~I2C_FUNC_SMBUS_PEC);
 559 }
 560
 561 static const struct i2c_algorithm mcp_i2c_algo = {
 562         .master_xfer = mcp_i2c_xfer,
 563         .smbus_xfer = mcp_smbus_xfer,
 564         .functionality = mcp_i2c_func,
 565 };
 566
 567 static int mcp_gpio_get(struct gpio_chip *gc,
 568                                 unsigned int offset)
 569 {
 570         int ret;
 571         struct mcp2221 *mcp = gpiochip_get_data(gc);
 572
 573         mcp->txbuf[0] = MCP2221_GPIO_GET;
 574
 575         mcp->gp_idx = offsetof(struct mcp_get_gpio, gpio[offset].value);
 576
 577         mutex_lock(&mcp->lock);
 578         ret = mcp_send_data_req_status(mcp, mcp->txbuf, 1);
 579         mutex_unlock(&mcp->lock);
 580
 581         return ret;
 582 }
 583
 584 static void mcp_gpio_set(struct gpio_chip *gc,
 585                                 unsigned int offset, int value)
 586 {
 587         struct mcp2221 *mcp = gpiochip_get_data(gc);
 588
 589         memset(mcp->txbuf, 0, 18);
 590         mcp->txbuf[0] = MCP2221_GPIO_SET;
 591
 592         mcp->gp_idx = offsetof(struct mcp_set_gpio, gpio[offset].value);
 593
 594         mcp->txbuf[mcp->gp_idx - 1] = 1;
 595         mcp->txbuf[mcp->gp_idx] = !!value;
 596
 597         mutex_lock(&mcp->lock);
 598         mcp_send_data_req_status(mcp, mcp->txbuf, 18);
 599         mutex_unlock(&mcp->lock);
 600 }
 601
 602 static int mcp_gpio_dir_set(struct mcp2221 *mcp,
 603                                 unsigned int offset, u8 val)
 604 {
 605         memset(mcp->txbuf, 0, 18);
 606         mcp->txbuf[0] = MCP2221_GPIO_SET;
 607
 608         mcp->gp_idx = offsetof(struct mcp_set_gpio, gpio[offset].direction);
 609
 610         mcp->txbuf[mcp->gp_idx - 1] = 1;
 611         mcp->txbuf[mcp->gp_idx] = val;
 612
 613         return mcp_send_data_req_status(mcp, mcp->txbuf, 18);
 614 }
 615
 616 static int mcp_gpio_direction_input(struct gpio_chip *gc,
 617                                 unsigned int offset)
 618 {
 619         int ret;
 620         struct mcp2221 *mcp = gpiochip_get_data(gc);
 621
 622         mutex_lock(&mcp->lock);
 623         ret = mcp_gpio_dir_set(mcp, offset, MCP2221_DIR_IN);
 624         mutex_unlock(&mcp->lock);
 625
 626         return ret;
 627 }
 628
 629 static int mcp_gpio_direction_output(struct gpio_chip *gc,
 630                                 unsigned int offset, int value)
 631 {
 632         int ret;
 633         struct mcp2221 *mcp = gpiochip_get_data(gc);
 634
 635         mutex_lock(&mcp->lock);
 636         ret = mcp_gpio_dir_set(mcp, offset, MCP2221_DIR_OUT);
 637         mutex_unlock(&mcp->lock);
 638
 639         /* Can't configure as output, bailout early */
 640         if (ret)
 641                 return ret;
 642
 643         mcp_gpio_set(gc, offset, value);
 644
 645         return 0;
 646 }
 647
 648 static int mcp_gpio_get_direction(struct gpio_chip *gc,
 649                                 unsigned int offset)
 650 {
 651         int ret;
 652         struct mcp2221 *mcp = gpiochip_get_data(gc);
 653
 654         mcp->txbuf[0] = MCP2221_GPIO_GET;
 655
 656         mcp->gp_idx = offsetof(struct mcp_get_gpio, gpio[offset].direction);
 657
 658         mutex_lock(&mcp->lock);
 659         ret = mcp_send_data_req_status(mcp, mcp->txbuf, 1);
 660         mutex_unlock(&mcp->lock);
 661
 662         if (ret)
 663                 return ret;
 664
 665         if (mcp->gpio_dir == MCP2221_DIR_IN)
 666                 return GPIO_LINE_DIRECTION_IN;
 667
 668         return GPIO_LINE_DIRECTION_OUT;
 669 }
 670
 671 /* Gives current state of i2c engine inside mcp2221 */
 672 static int mcp_get_i2c_eng_state(struct mcp2221 *mcp,
 673                                 u8 *data, u8 idx)
 674 {
 675         int ret;
 676
 677         switch (data[idx]) {
 678         case MCP2221_I2C_WRADDRL_NACK:
 679         case MCP2221_I2C_WRADDRL_SEND:
 680                 ret = -ENXIO;
 681                 break;
 682         case MCP2221_I2C_START_TOUT:
 683         case MCP2221_I2C_STOP_TOUT:
 684         case MCP2221_I2C_WRADDRL_TOUT:
 685         case MCP2221_I2C_WRDATA_TOUT:
 686                 ret = -ETIMEDOUT;
 687                 break;
 688         case MCP2221_I2C_ENG_BUSY:
 689                 ret = -EAGAIN;
 690                 break;
 691         case MCP2221_SUCCESS:
 692                 ret = 0x00;
 693                 break;
 694         default:
 695                 ret = -EIO;
 696         }
 697
 698         return ret;
 699 }
 700
 701 /*
 702  * MCP2221 uses interrupt endpoint for input reports. This function
 703  * is called by HID layer when it receives i/p report from mcp2221,
 704  * which is actually a response to the previously sent command.
 705  *
 706  * MCP2221A firmware specific return codes are parsed and 0 or
 707  * appropriate negative error code is returned. Delayed response
 708  * results in timeout error and stray reponses results in -EIO.
 709  */
 710 static int mcp2221_raw_event(struct hid_device *hdev,
 711                                 struct hid_report *report, u8 *data, int size)
 712 {
 713         u8 *buf;
 714         struct mcp2221 *mcp = hid_get_drvdata(hdev);
 715
 716         switch (data[0]) {
 717
 718         case MCP2221_I2C_WR_DATA:
 719         case MCP2221_I2C_WR_NO_STOP:
 720         case MCP2221_I2C_RD_DATA:
 721         case MCP2221_I2C_RD_RPT_START:
 722                 switch (data[1]) {
 723                 case MCP2221_SUCCESS:
 724                         mcp->status = 0;
 725                         break;
 726                 default:
 727                         mcp->status = mcp_get_i2c_eng_state(mcp, data, 2);
 728                 }
 729                 complete(&mcp->wait_in_report);
 730                 break;
 731
 732         case MCP2221_I2C_PARAM_OR_STATUS:
 733                 switch (data[1]) {
 734                 case MCP2221_SUCCESS:
 735                         if ((mcp->txbuf[3] == MCP2221_I2C_SET_SPEED) &&
 736                                 (data[3] != MCP2221_I2C_SET_SPEED)) {
 737                                 mcp->status = -EAGAIN;
 738                                 break;
 739                         }
 740                         if (data[20] & MCP2221_I2C_MASK_ADDR_NACK) {
 741                                 mcp->status = -ENXIO;
 742                                 break;
 743                         }
 744                         mcp->status = mcp_get_i2c_eng_state(mcp, data, 8);
 745                         break;
 746                 default:
 747                         mcp->status = -EIO;
 748                 }
 749                 complete(&mcp->wait_in_report);
 750                 break;
 751
 752         case MCP2221_I2C_GET_DATA:
 753                 switch (data[1]) {
 754                 case MCP2221_SUCCESS:
 755                         if (data[2] == MCP2221_I2C_ADDR_NACK) {
 756                                 mcp->status = -ENXIO;
 757                                 break;
 758                         }
 759                         if (!mcp_get_i2c_eng_state(mcp, data, 2)
 760                                 && (data[3] == 0)) {
 761                                 mcp->status = 0;
 762                                 break;
 763                         }
 764                         if (data[3] == 127) {
 765                                 mcp->status = -EIO;
 766                                 break;
 767                         }
 768                         if (data[2] == MCP2221_I2C_READ_COMPL) {
 769                                 buf = mcp->rxbuf;
 770                                 memcpy(&buf[mcp->rxbuf_idx], &data[4], data[3]);
 771                                 mcp->rxbuf_idx = mcp->rxbuf_idx + data[3];
 772                                 mcp->status = 0;
 773                                 break;
 774                         }
 775                         mcp->status = -EIO;
 776                         break;
 777                 default:
 778                         mcp->status = -EIO;
 779                 }
 780                 complete(&mcp->wait_in_report);
 781                 break;
 782
 783         case MCP2221_GPIO_GET:
 784                 switch (data[1]) {
 785                 case MCP2221_SUCCESS:
 786                         if ((data[mcp->gp_idx] == MCP2221_ALT_F_NOT_GPIOV) ||
 787                                 (data[mcp->gp_idx + 1] == MCP2221_ALT_F_NOT_GPIOD)) {
 788                                 mcp->status = -ENOENT;
 789                         } else {
 790                                 mcp->status = !!data[mcp->gp_idx];
 791                                 mcp->gpio_dir = data[mcp->gp_idx + 1];
 792                         }
 793                         break;
 794                 default:
 795                         mcp->status = -EAGAIN;
 796                 }
 797                 complete(&mcp->wait_in_report);
 798                 break;
 799
 800         case MCP2221_GPIO_SET:
 801                 switch (data[1]) {
 802                 case MCP2221_SUCCESS:
 803                         if ((data[mcp->gp_idx] == MCP2221_ALT_F_NOT_GPIOV) ||
 804                                 (data[mcp->gp_idx - 1] == MCP2221_ALT_F_NOT_GPIOV)) {
 805                                 mcp->status = -ENOENT;
 806                         } else {
 807                                 mcp->status = 0;
 808                         }
 809                         break;
 810                 default:
 811                         mcp->status = -EAGAIN;
 812                 }
 813                 complete(&mcp->wait_in_report);
 814                 break;
 815
 816         default:
 817                 mcp->status = -EIO;
 818                 complete(&mcp->wait_in_report);
 819         }
 820
 821         return 1;
 822 }
 823
 824 static int mcp2221_probe(struct hid_device *hdev,
 825                                         const struct hid_device_id *id)
 826 {
 827         int ret;
 828         struct mcp2221 *mcp;
 829
 830         mcp = devm_kzalloc(&hdev->dev, sizeof(*mcp), GFP_KERNEL);
 831         if (!mcp)
 832                 return -ENOMEM;
 833
 834         ret = hid_parse(hdev);
 835         if (ret) {
 836                 hid_err(hdev, "can't parse reports\n");
 837                 return ret;
 838         }
 839
 840         ret = hid_hw_start(hdev, HID_CONNECT_HIDRAW);
 841         if (ret) {
 842                 hid_err(hdev, "can't start hardware\n");
 843                 return ret;
 844         }
 845
 846         ret = hid_hw_open(hdev);
 847         if (ret) {
 848                 hid_err(hdev, "can't open device\n");
 849                 goto err_hstop;
 850         }
 851
 852         mutex_init(&mcp->lock);
 853         init_completion(&mcp->wait_in_report);
 854         hid_set_drvdata(hdev, mcp);
 855         mcp->hdev = hdev;
 856
 857         /* Set I2C bus clock diviser */
 858         if (i2c_clk_freq > 400)
 859                 i2c_clk_freq = 400;
 860         if (i2c_clk_freq < 50)
 861                 i2c_clk_freq = 50;
 862         mcp->cur_i2c_clk_div = (12000000 / (i2c_clk_freq * 1000)) - 3;
 863
 864         mcp->adapter.owner = THIS_MODULE;
 865         mcp->adapter.class = I2C_CLASS_HWMON;
 866         mcp->adapter.algo = &mcp_i2c_algo;
 867         mcp->adapter.retries = 1;
 868         mcp->adapter.dev.parent = &hdev->dev;
 869         snprintf(mcp->adapter.name, sizeof(mcp->adapter.name),
 870                         "MCP2221 usb-i2c bridge on hidraw%d",
 871                         ((struct hidraw *)hdev->hidraw)->minor);
 872
 873         ret = i2c_add_adapter(&mcp->adapter);
 874         if (ret) {
 875                 hid_err(hdev, "can't add usb-i2c adapter: %d\n", ret);
 876                 goto err_i2c;
 877         }
 878         i2c_set_adapdata(&mcp->adapter, mcp);
 879
 880         /* Setup GPIO chip */
 881         mcp->gc = devm_kzalloc(&hdev->dev, sizeof(*mcp->gc), GFP_KERNEL);
 882         if (!mcp->gc) {
 883                 ret = -ENOMEM;
 884                 goto err_gc;
 885         }
 886
 887         mcp->gc->label = "mcp2221_gpio";
 888         mcp->gc->direction_input = mcp_gpio_direction_input;
 889         mcp->gc->direction_output = mcp_gpio_direction_output;
 890         mcp->gc->get_direction = mcp_gpio_get_direction;
 891         mcp->gc->set = mcp_gpio_set;
 892         mcp->gc->get = mcp_gpio_get;
 893         mcp->gc->ngpio = MCP_NGPIO;
 894         mcp->gc->base = -1;
 895         mcp->gc->can_sleep = 1;
 896         mcp->gc->parent = &hdev->dev;
 897
 898         ret = devm_gpiochip_add_data(&hdev->dev, mcp->gc, mcp);
 899         if (ret)
 900                 goto err_gc;
 901
 902         return 0;
 903
 904 err_gc:
 905         i2c_del_adapter(&mcp->adapter);
 906 err_i2c:
 907         hid_hw_close(mcp->hdev);
 908 err_hstop:
 909         hid_hw_stop(mcp->hdev);
 910         return ret;
 911 }
 912
 913 static void mcp2221_remove(struct hid_device *hdev)
 914 {
 915         struct mcp2221 *mcp = hid_get_drvdata(hdev);
 916
 917         i2c_del_adapter(&mcp->adapter);
 918         hid_hw_close(mcp->hdev);
 919         hid_hw_stop(mcp->hdev);
 920 }
 921
 922 static const struct hid_device_id mcp2221_devices[] = {
 923         { HID_USB_DEVICE(USB_VENDOR_ID_MICROCHIP, USB_DEVICE_ID_MCP2221) },
 924         { }
 925 };
 926 MODULE_DEVICE_TABLE(hid, mcp2221_devices);
 927
 928 static struct hid_driver mcp2221_driver = {
 929         .name           = "mcp2221",
 930         .id_table       = mcp2221_devices,
 931         .probe          = mcp2221_probe,
 932         .remove         = mcp2221_remove,
 933         .raw_event      = mcp2221_raw_event,
 934 };
 935
 936 /* Register with HID core */
 937 module_hid_driver(mcp2221_driver);
 938
 939 MODULE_AUTHOR("Rishi Gupta <gupt21@gmail.com>");
 940 MODULE_DESCRIPTION("MCP2221 Microchip HID USB to I2C master bridge");
 941 MODULE_LICENSE("GPL v2");