linux/drivers/hid/hid-mcp2221.c
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   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 */
  22enum {
  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 */
  36enum {
  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 */
  53enum {
  54        MCP2221_DIR_OUT = 0x00,
  55        MCP2221_DIR_IN = 0x01,
  56};
  57
  58#define MCP_NGPIO       4
  59
  60/* MCP GPIO set command layout */
  61struct 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 */
  73struct 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 */
  87struct 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 */
 106static uint i2c_clk_freq = 400;
 107
 108/* Synchronously send output report to the device */
 109static 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 */
 133static 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 */
 154static 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 */
 163static 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
 172static 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 */
 199static 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 */
 257static 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
 303static 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
 356exit:
 357        hid_hw_power(mcp->hdev, PM_HINT_NORMAL);
 358        mutex_unlock(&mcp->lock);
 359        return ret;
 360}
 361
 362static 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
 407static 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
 547exit:
 548        hid_hw_power(mcp->hdev, PM_HINT_NORMAL);
 549        mutex_unlock(&mcp->lock);
 550        return ret;
 551}
 552
 553static 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
 561static 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
 567static 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
 584static 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
 602static 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
 616static 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
 629static 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
 648static 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 */
 672static 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 */
 710static 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
 824static 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
 904err_gc:
 905        i2c_del_adapter(&mcp->adapter);
 906err_i2c:
 907        hid_hw_close(mcp->hdev);
 908err_hstop:
 909        hid_hw_stop(mcp->hdev);
 910        return ret;
 911}
 912
 913static 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
 922static const struct hid_device_id mcp2221_devices[] = {
 923        { HID_USB_DEVICE(USB_VENDOR_ID_MICROCHIP, USB_DEVICE_ID_MCP2221) },
 924        { }
 925};
 926MODULE_DEVICE_TABLE(hid, mcp2221_devices);
 927
 928static 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 */
 937module_hid_driver(mcp2221_driver);
 938
 939MODULE_AUTHOR("Rishi Gupta <gupt21@gmail.com>");
 940MODULE_DESCRIPTION("MCP2221 Microchip HID USB to I2C master bridge");
 941MODULE_LICENSE("GPL v2");
 942