LXR linux/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 */
  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/*
  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 */
  57struct 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 */
  76static uint i2c_clk_freq = 400;
  77
  78/* Synchronously send output report to the device */
  79static 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 */
 103static 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 */
 124static 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 */
 133static 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
 142static 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 */
 169static 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 */
 227static 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
 273static 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
 326exit:
 327        hid_hw_power(mcp->hdev, PM_HINT_NORMAL);
 328        mutex_unlock(&mcp->lock);
 329        return ret;
 330}
 331
 332static 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
 377static 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
 517exit:
 518        hid_hw_power(mcp->hdev, PM_HINT_NORMAL);
 519        mutex_unlock(&mcp->lock);
 520        return ret;
 521}
 522
 523static 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
 531static 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
 537static 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
 554static 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
 572static 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
 586static 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
 599static 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
 618static 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 */
 642static 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 */
 680static 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
 794static 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
 874err_gc:
 875        i2c_del_adapter(&mcp->adapter);
 876err_i2c:
 877        hid_hw_close(mcp->hdev);
 878err_hstop:
 879        hid_hw_stop(mcp->hdev);
 880        return ret;
 881}
 882
 883static 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
 892static const struct hid_device_id mcp2221_devices[] = {
 893        { HID_USB_DEVICE(USB_VENDOR_ID_MICROCHIP, USB_DEVICE_ID_MCP2221) },
 894        { }
 895};
 896MODULE_DEVICE_TABLE(hid, mcp2221_devices);
 897
 898static 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 */
 907module_hid_driver(mcp2221_driver);
 908
 909MODULE_AUTHOR("Rishi Gupta <gupt21@gmail.com>");
 910MODULE_DESCRIPTION("MCP2221 Microchip HID USB to I2C master bridge");
 911MODULE_LICENSE("GPL v2");
 912