kernel/drivers/hid/hid-cp2112.c

   1 /*
   2  * hid-cp2112.c - Silicon Labs HID USB to SMBus master bridge
   3  * Copyright (c) 2013,2014 Uplogix, Inc.
   4  * David Barksdale <dbarksdale@uplogix.com>
   5  *
   6  * This program is free software; you can redistribute it and/or modify it
   7  * under the terms and conditions of the GNU General Public License,
   8  * version 2, as published by the Free Software Foundation.
   9  *
  10  * This program is distributed in the hope it will be useful, but WITHOUT
  11  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  12  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  13  * more details.
  14  */
  15
  16 /*
  17  * The Silicon Labs CP2112 chip is a USB HID device which provides an
  18  * SMBus controller for talking to slave devices and 8 GPIO pins. The
  19  * host communicates with the CP2112 via raw HID reports.
  20  *
  21  * Data Sheet:
  22  *   http://www.silabs.com/Support%20Documents/TechnicalDocs/CP2112.pdf
  23  * Programming Interface Specification:
  24  *   http://www.silabs.com/Support%20Documents/TechnicalDocs/AN495.pdf
  25  */
  26
  27 #include <linux/gpio.h>
  28 #include <linux/hid.h>
  29 #include <linux/i2c.h>
  30 #include <linux/module.h>
  31 #include <linux/nls.h>
  32 #include <linux/usb/ch9.h>
  33 #include "hid-ids.h"
  34
  35 enum {
  36         CP2112_GPIO_CONFIG              = 0x02,
  37         CP2112_GPIO_GET                 = 0x03,
  38         CP2112_GPIO_SET                 = 0x04,
  39         CP2112_GET_VERSION_INFO         = 0x05,
  40         CP2112_SMBUS_CONFIG             = 0x06,
  41         CP2112_DATA_READ_REQUEST        = 0x10,
  42         CP2112_DATA_WRITE_READ_REQUEST  = 0x11,
  43         CP2112_DATA_READ_FORCE_SEND     = 0x12,
  44         CP2112_DATA_READ_RESPONSE       = 0x13,
  45         CP2112_DATA_WRITE_REQUEST       = 0x14,
  46         CP2112_TRANSFER_STATUS_REQUEST  = 0x15,
  47         CP2112_TRANSFER_STATUS_RESPONSE = 0x16,
  48         CP2112_CANCEL_TRANSFER          = 0x17,
  49         CP2112_LOCK_BYTE                = 0x20,
  50         CP2112_USB_CONFIG               = 0x21,
  51         CP2112_MANUFACTURER_STRING      = 0x22,
  52         CP2112_PRODUCT_STRING           = 0x23,
  53         CP2112_SERIAL_STRING            = 0x24,
  54 };
  55
  56 enum {
  57         STATUS0_IDLE            = 0x00,
  58         STATUS0_BUSY            = 0x01,
  59         STATUS0_COMPLETE        = 0x02,
  60         STATUS0_ERROR           = 0x03,
  61 };
  62
  63 enum {
  64         STATUS1_TIMEOUT_NACK            = 0x00,
  65         STATUS1_TIMEOUT_BUS             = 0x01,
  66         STATUS1_ARBITRATION_LOST        = 0x02,
  67         STATUS1_READ_INCOMPLETE         = 0x03,
  68         STATUS1_WRITE_INCOMPLETE        = 0x04,
  69         STATUS1_SUCCESS                 = 0x05,
  70 };
  71
  72 struct cp2112_smbus_config_report {
  73         u8 report;              /* CP2112_SMBUS_CONFIG */
  74         __be32 clock_speed;     /* Hz */
  75         u8 device_address;      /* Stored in the upper 7 bits */
  76         u8 auto_send_read;      /* 1 = enabled, 0 = disabled */
  77         __be16 write_timeout;   /* ms, 0 = no timeout */
  78         __be16 read_timeout;    /* ms, 0 = no timeout */
  79         u8 scl_low_timeout;     /* 1 = enabled, 0 = disabled */
  80         __be16 retry_time;      /* # of retries, 0 = no limit */
  81 } __packed;
  82
  83 struct cp2112_usb_config_report {
  84         u8 report;      /* CP2112_USB_CONFIG */
  85         __le16 vid;     /* Vendor ID */
  86         __le16 pid;     /* Product ID */
  87         u8 max_power;   /* Power requested in 2mA units */
  88         u8 power_mode;  /* 0x00 = bus powered
  89                            0x01 = self powered & regulator off
  90                            0x02 = self powered & regulator on */
  91         u8 release_major;
  92         u8 release_minor;
  93         u8 mask;        /* What fields to program */
  94 } __packed;
  95
  96 struct cp2112_read_req_report {
  97         u8 report;      /* CP2112_DATA_READ_REQUEST */
  98         u8 slave_address;
  99         __be16 length;
 100 } __packed;
 101
 102 struct cp2112_write_read_req_report {
 103         u8 report;      /* CP2112_DATA_WRITE_READ_REQUEST */
 104         u8 slave_address;
 105         __be16 length;
 106         u8 target_address_length;
 107         u8 target_address[16];
 108 } __packed;
 109
 110 struct cp2112_write_req_report {
 111         u8 report;      /* CP2112_DATA_WRITE_REQUEST */
 112         u8 slave_address;
 113         u8 length;
 114         u8 data[61];
 115 } __packed;
 116
 117 struct cp2112_force_read_report {
 118         u8 report;      /* CP2112_DATA_READ_FORCE_SEND */
 119         __be16 length;
 120 } __packed;
 121
 122 struct cp2112_xfer_status_report {
 123         u8 report;      /* CP2112_TRANSFER_STATUS_RESPONSE */
 124         u8 status0;     /* STATUS0_* */
 125         u8 status1;     /* STATUS1_* */
 126         __be16 retries;
 127         __be16 length;
 128 } __packed;
 129
 130 struct cp2112_string_report {
 131         u8 dummy;               /* force .string to be aligned */
 132         u8 report;              /* CP2112_*_STRING */
 133         u8 length;              /* length in bytes of everyting after .report */
 134         u8 type;                /* USB_DT_STRING */
 135         wchar_t string[30];     /* UTF16_LITTLE_ENDIAN string */
 136 } __packed;
 137
 138 /* Number of times to request transfer status before giving up waiting for a
 139    transfer to complete. This may need to be changed if SMBUS clock, retries,
 140    or read/write/scl_low timeout settings are changed. */
 141 static const int XFER_STATUS_RETRIES = 10;
 142
 143 /* Time in ms to wait for a CP2112_DATA_READ_RESPONSE or
 144    CP2112_TRANSFER_STATUS_RESPONSE. */
 145 static const int RESPONSE_TIMEOUT = 50;
 146
 147 static const struct hid_device_id cp2112_devices[] = {
 148         { HID_USB_DEVICE(USB_VENDOR_ID_CYGNAL, USB_DEVICE_ID_CYGNAL_CP2112) },
 149         { }
 150 };
 151 MODULE_DEVICE_TABLE(hid, cp2112_devices);
 152
 153 struct cp2112_device {
 154         struct i2c_adapter adap;
 155         struct hid_device *hdev;
 156         wait_queue_head_t wait;
 157         u8 read_data[61];
 158         u8 read_length;
 159         int xfer_status;
 160         atomic_t read_avail;
 161         atomic_t xfer_avail;
 162         struct gpio_chip gc;
 163 };
 164
 165 static int gpio_push_pull = 0xFF;
 166 module_param(gpio_push_pull, int, S_IRUGO | S_IWUSR);
 167 MODULE_PARM_DESC(gpio_push_pull, "GPIO push-pull configuration bitmask");
 168
 169 static int cp2112_gpio_direction_input(struct gpio_chip *chip, unsigned offset)
 170 {
 171         struct cp2112_device *dev = container_of(chip, struct cp2112_device,
 172                                                  gc);
 173         struct hid_device *hdev = dev->hdev;
 174         u8 buf[5];
 175         int ret;
 176
 177         ret = hid_hw_raw_request(hdev, CP2112_GPIO_CONFIG, buf,
 178                                        sizeof(buf), HID_FEATURE_REPORT,
 179                                        HID_REQ_GET_REPORT);
 180         if (ret != sizeof(buf)) {
 181                 hid_err(hdev, "error requesting GPIO config: %d\n", ret);
 182                 return ret;
 183         }
 184
 185         buf[1] &= ~(1 << offset);
 186         buf[2] = gpio_push_pull;
 187
 188         ret = hid_hw_raw_request(hdev, CP2112_GPIO_CONFIG, buf, sizeof(buf),
 189                                  HID_FEATURE_REPORT, HID_REQ_SET_REPORT);
 190         if (ret < 0) {
 191                 hid_err(hdev, "error setting GPIO config: %d\n", ret);
 192                 return ret;
 193         }
 194
 195         return 0;
 196 }
 197
 198 static void cp2112_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
 199 {
 200         struct cp2112_device *dev = container_of(chip, struct cp2112_device,
 201                                                  gc);
 202         struct hid_device *hdev = dev->hdev;
 203         u8 buf[3];
 204         int ret;
 205
 206         buf[0] = CP2112_GPIO_SET;
 207         buf[1] = value ? 0xff : 0;
 208         buf[2] = 1 << offset;
 209
 210         ret = hid_hw_raw_request(hdev, CP2112_GPIO_SET, buf, sizeof(buf),
 211                                  HID_FEATURE_REPORT, HID_REQ_SET_REPORT);
 212         if (ret < 0)
 213                 hid_err(hdev, "error setting GPIO values: %d\n", ret);
 214 }
 215
 216 static int cp2112_gpio_get(struct gpio_chip *chip, unsigned offset)
 217 {
 218         struct cp2112_device *dev = container_of(chip, struct cp2112_device,
 219                                                  gc);
 220         struct hid_device *hdev = dev->hdev;
 221         u8 buf[2];
 222         int ret;
 223
 224         ret = hid_hw_raw_request(hdev, CP2112_GPIO_GET, buf, sizeof(buf),
 225                                        HID_FEATURE_REPORT, HID_REQ_GET_REPORT);
 226         if (ret != sizeof(buf)) {
 227                 hid_err(hdev, "error requesting GPIO values: %d\n", ret);
 228                 return ret;
 229         }
 230
 231         return (buf[1] >> offset) & 1;
 232 }
 233
 234 static int cp2112_gpio_direction_output(struct gpio_chip *chip,
 235                                         unsigned offset, int value)
 236 {
 237         struct cp2112_device *dev = container_of(chip, struct cp2112_device,
 238                                                  gc);
 239         struct hid_device *hdev = dev->hdev;
 240         u8 buf[5];
 241         int ret;
 242
 243         ret = hid_hw_raw_request(hdev, CP2112_GPIO_CONFIG, buf,
 244                                        sizeof(buf), HID_FEATURE_REPORT,
 245                                        HID_REQ_GET_REPORT);
 246         if (ret != sizeof(buf)) {
 247                 hid_err(hdev, "error requesting GPIO config: %d\n", ret);
 248                 return ret;
 249         }
 250
 251         buf[1] |= 1 << offset;
 252         buf[2] = gpio_push_pull;
 253
 254         ret = hid_hw_raw_request(hdev, CP2112_GPIO_CONFIG, buf, sizeof(buf),
 255                                  HID_FEATURE_REPORT, HID_REQ_SET_REPORT);
 256         if (ret < 0) {
 257                 hid_err(hdev, "error setting GPIO config: %d\n", ret);
 258                 return ret;
 259         }
 260
 261         /*
 262          * Set gpio value when output direction is already set,
 263          * as specified in AN495, Rev. 0.2, cpt. 4.4
 264          */
 265         cp2112_gpio_set(chip, offset, value);
 266
 267         return 0;
 268 }
 269
 270 static int cp2112_hid_get(struct hid_device *hdev, unsigned char report_number,
 271                           u8 *data, size_t count, unsigned char report_type)
 272 {
 273         u8 *buf;
 274         int ret;
 275
 276         buf = kmalloc(count, GFP_KERNEL);
 277         if (!buf)
 278                 return -ENOMEM;
 279
 280         ret = hid_hw_raw_request(hdev, report_number, buf, count,
 281                                        report_type, HID_REQ_GET_REPORT);
 282         memcpy(data, buf, count);
 283         kfree(buf);
 284         return ret;
 285 }
 286
 287 static int cp2112_hid_output(struct hid_device *hdev, u8 *data, size_t count,
 288                              unsigned char report_type)
 289 {
 290         u8 *buf;
 291         int ret;
 292
 293         buf = kmemdup(data, count, GFP_KERNEL);
 294         if (!buf)
 295                 return -ENOMEM;
 296
 297         if (report_type == HID_OUTPUT_REPORT)
 298                 ret = hid_hw_output_report(hdev, buf, count);
 299         else
 300                 ret = hid_hw_raw_request(hdev, buf[0], buf, count, report_type,
 301                                 HID_REQ_SET_REPORT);
 302
 303         kfree(buf);
 304         return ret;
 305 }
 306
 307 static int cp2112_wait(struct cp2112_device *dev, atomic_t *avail)
 308 {
 309         int ret = 0;
 310
 311         /* We have sent either a CP2112_TRANSFER_STATUS_REQUEST or a
 312          * CP2112_DATA_READ_FORCE_SEND and we are waiting for the response to
 313          * come in cp2112_raw_event or timeout. There will only be one of these
 314          * in flight at any one time. The timeout is extremely large and is a
 315          * last resort if the CP2112 has died. If we do timeout we don't expect
 316          * to receive the response which would cause data races, it's not like
 317          * we can do anything about it anyway.
 318          */
 319         ret = wait_event_interruptible_timeout(dev->wait,
 320                 atomic_read(avail), msecs_to_jiffies(RESPONSE_TIMEOUT));
 321         if (-ERESTARTSYS == ret)
 322                 return ret;
 323         if (!ret)
 324                 return -ETIMEDOUT;
 325
 326         atomic_set(avail, 0);
 327         return 0;
 328 }
 329
 330 static int cp2112_xfer_status(struct cp2112_device *dev)
 331 {
 332         struct hid_device *hdev = dev->hdev;
 333         u8 buf[2];
 334         int ret;
 335
 336         buf[0] = CP2112_TRANSFER_STATUS_REQUEST;
 337         buf[1] = 0x01;
 338         atomic_set(&dev->xfer_avail, 0);
 339
 340         ret = cp2112_hid_output(hdev, buf, 2, HID_OUTPUT_REPORT);
 341         if (ret < 0) {
 342                 hid_warn(hdev, "Error requesting status: %d\n", ret);
 343                 return ret;
 344         }
 345
 346         ret = cp2112_wait(dev, &dev->xfer_avail);
 347         if (ret)
 348                 return ret;
 349
 350         return dev->xfer_status;
 351 }
 352
 353 static int cp2112_read(struct cp2112_device *dev, u8 *data, size_t size)
 354 {
 355         struct hid_device *hdev = dev->hdev;
 356         struct cp2112_force_read_report report;
 357         int ret;
 358
 359         if (size > sizeof(dev->read_data))
 360                 size = sizeof(dev->read_data);
 361         report.report = CP2112_DATA_READ_FORCE_SEND;
 362         report.length = cpu_to_be16(size);
 363
 364         atomic_set(&dev->read_avail, 0);
 365
 366         ret = cp2112_hid_output(hdev, &report.report, sizeof(report),
 367                                 HID_OUTPUT_REPORT);
 368         if (ret < 0) {
 369                 hid_warn(hdev, "Error requesting data: %d\n", ret);
 370                 return ret;
 371         }
 372
 373         ret = cp2112_wait(dev, &dev->read_avail);
 374         if (ret)
 375                 return ret;
 376
 377         hid_dbg(hdev, "read %d of %zd bytes requested\n",
 378                 dev->read_length, size);
 379
 380         if (size > dev->read_length)
 381                 size = dev->read_length;
 382
 383         memcpy(data, dev->read_data, size);
 384         return dev->read_length;
 385 }
 386
 387 static int cp2112_read_req(void *buf, u8 slave_address, u16 length)
 388 {
 389         struct cp2112_read_req_report *report = buf;
 390
 391         if (length < 1 || length > 512)
 392                 return -EINVAL;
 393
 394         report->report = CP2112_DATA_READ_REQUEST;
 395         report->slave_address = slave_address << 1;
 396         report->length = cpu_to_be16(length);
 397         return sizeof(*report);
 398 }
 399
 400 static int cp2112_write_read_req(void *buf, u8 slave_address, u16 length,
 401                                  u8 command, u8 *data, u8 data_length)
 402 {
 403         struct cp2112_write_read_req_report *report = buf;
 404
 405         if (length < 1 || length > 512
 406             || data_length > sizeof(report->target_address) - 1)
 407                 return -EINVAL;
 408
 409         report->report = CP2112_DATA_WRITE_READ_REQUEST;
 410         report->slave_address = slave_address << 1;
 411         report->length = cpu_to_be16(length);
 412         report->target_address_length = data_length + 1;
 413         report->target_address[0] = command;
 414         memcpy(&report->target_address[1], data, data_length);
 415         return data_length + 6;
 416 }
 417
 418 static int cp2112_write_req(void *buf, u8 slave_address, u8 command, u8 *data,
 419                             u8 data_length)
 420 {
 421         struct cp2112_write_req_report *report = buf;
 422
 423         if (data_length > sizeof(report->data) - 1)
 424                 return -EINVAL;
 425
 426         report->report = CP2112_DATA_WRITE_REQUEST;
 427         report->slave_address = slave_address << 1;
 428         report->length = data_length + 1;
 429         report->data[0] = command;
 430         memcpy(&report->data[1], data, data_length);
 431         return data_length + 4;
 432 }
 433
 434 static int cp2112_i2c_write_req(void *buf, u8 slave_address, u8 *data,
 435                                 u8 data_length)
 436 {
 437         struct cp2112_write_req_report *report = buf;
 438
 439         if (data_length > sizeof(report->data))
 440                 return -EINVAL;
 441
 442         report->report = CP2112_DATA_WRITE_REQUEST;
 443         report->slave_address = slave_address << 1;
 444         report->length = data_length;
 445         memcpy(report->data, data, data_length);
 446         return data_length + 3;
 447 }
 448
 449 static int cp2112_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
 450                            int num)
 451 {
 452         struct cp2112_device *dev = (struct cp2112_device *)adap->algo_data;
 453         struct hid_device *hdev = dev->hdev;
 454         u8 buf[64];
 455         ssize_t count;
 456         unsigned int retries;
 457         int ret;
 458
 459         hid_dbg(hdev, "I2C %d messages\n", num);
 460
 461         if (num != 1) {
 462                 hid_err(hdev,
 463                         "Multi-message I2C transactions not supported\n");
 464                 return -EOPNOTSUPP;
 465         }
 466
 467         if (msgs->flags & I2C_M_RD)
 468                 count = cp2112_read_req(buf, msgs->addr, msgs->len);
 469         else
 470                 count = cp2112_i2c_write_req(buf, msgs->addr, msgs->buf,
 471                                              msgs->len);
 472
 473         if (count < 0)
 474                 return count;
 475
 476         ret = hid_hw_power(hdev, PM_HINT_FULLON);
 477         if (ret < 0) {
 478                 hid_err(hdev, "power management error: %d\n", ret);
 479                 return ret;
 480         }
 481
 482         ret = cp2112_hid_output(hdev, buf, count, HID_OUTPUT_REPORT);
 483         if (ret < 0) {
 484                 hid_warn(hdev, "Error starting transaction: %d\n", ret);
 485                 goto power_normal;
 486         }
 487
 488         for (retries = 0; retries < XFER_STATUS_RETRIES; ++retries) {
 489                 ret = cp2112_xfer_status(dev);
 490                 if (-EBUSY == ret)
 491                         continue;
 492                 if (ret < 0)
 493                         goto power_normal;
 494                 break;
 495         }
 496
 497         if (XFER_STATUS_RETRIES <= retries) {
 498                 hid_warn(hdev, "Transfer timed out, cancelling.\n");
 499                 buf[0] = CP2112_CANCEL_TRANSFER;
 500                 buf[1] = 0x01;
 501
 502                 ret = cp2112_hid_output(hdev, buf, 2, HID_OUTPUT_REPORT);
 503                 if (ret < 0)
 504                         hid_warn(hdev, "Error cancelling transaction: %d\n",
 505                                  ret);
 506
 507                 ret = -ETIMEDOUT;
 508                 goto power_normal;
 509         }
 510
 511         if (!(msgs->flags & I2C_M_RD))
 512                 goto finish;
 513
 514         ret = cp2112_read(dev, msgs->buf, msgs->len);
 515         if (ret < 0)
 516                 goto power_normal;
 517         if (ret != msgs->len) {
 518                 hid_warn(hdev, "short read: %d < %d\n", ret, msgs->len);
 519                 ret = -EIO;
 520                 goto power_normal;
 521         }
 522
 523 finish:
 524         /* return the number of transferred messages */
 525         ret = 1;
 526
 527 power_normal:
 528         hid_hw_power(hdev, PM_HINT_NORMAL);
 529         hid_dbg(hdev, "I2C transfer finished: %d\n", ret);
 530         return ret;
 531 }
 532
 533 static int cp2112_xfer(struct i2c_adapter *adap, u16 addr,
 534                        unsigned short flags, char read_write, u8 command,
 535                        int size, union i2c_smbus_data *data)
 536 {
 537         struct cp2112_device *dev = (struct cp2112_device *)adap->algo_data;
 538         struct hid_device *hdev = dev->hdev;
 539         u8 buf[64];
 540         __le16 word;
 541         ssize_t count;
 542         size_t read_length = 0;
 543         unsigned int retries;
 544         int ret;
 545
 546         hid_dbg(hdev, "%s addr 0x%x flags 0x%x cmd 0x%x size %d\n",
 547                 read_write == I2C_SMBUS_WRITE ? "write" : "read",
 548                 addr, flags, command, size);
 549
 550         switch (size) {
 551         case I2C_SMBUS_BYTE:
 552                 read_length = 1;
 553
 554                 if (I2C_SMBUS_READ == read_write)
 555                         count = cp2112_read_req(buf, addr, read_length);
 556                 else
 557                         count = cp2112_write_req(buf, addr, command, NULL,
 558                                                  0);
 559                 break;
 560         case I2C_SMBUS_BYTE_DATA:
 561                 read_length = 1;
 562
 563                 if (I2C_SMBUS_READ == read_write)
 564                         count = cp2112_write_read_req(buf, addr, read_length,
 565                                                       command, NULL, 0);
 566                 else
 567                         count = cp2112_write_req(buf, addr, command,
 568                                                  &data->byte, 1);
 569                 break;
 570         case I2C_SMBUS_WORD_DATA:
 571                 read_length = 2;
 572                 word = cpu_to_le16(data->word);
 573
 574                 if (I2C_SMBUS_READ == read_write)
 575                         count = cp2112_write_read_req(buf, addr, read_length,
 576                                                       command, NULL, 0);
 577                 else
 578                         count = cp2112_write_req(buf, addr, command,
 579                                                  (u8 *)&word, 2);
 580                 break;
 581         case I2C_SMBUS_PROC_CALL:
 582                 size = I2C_SMBUS_WORD_DATA;
 583                 read_write = I2C_SMBUS_READ;
 584                 read_length = 2;
 585                 word = cpu_to_le16(data->word);
 586
 587                 count = cp2112_write_read_req(buf, addr, read_length, command,
 588                                               (u8 *)&word, 2);
 589                 break;
 590         case I2C_SMBUS_I2C_BLOCK_DATA:
 591                 size = I2C_SMBUS_BLOCK_DATA;
 592                 /* fallthrough */
 593         case I2C_SMBUS_BLOCK_DATA:
 594                 if (I2C_SMBUS_READ == read_write) {
 595                         count = cp2112_write_read_req(buf, addr,
 596                                                       I2C_SMBUS_BLOCK_MAX,
 597                                                       command, NULL, 0);
 598                 } else {
 599                         count = cp2112_write_req(buf, addr, command,
 600                                                  data->block,
 601                                                  data->block[0] + 1);
 602                 }
 603                 break;
 604         case I2C_SMBUS_BLOCK_PROC_CALL:
 605                 size = I2C_SMBUS_BLOCK_DATA;
 606                 read_write = I2C_SMBUS_READ;
 607
 608                 count = cp2112_write_read_req(buf, addr, I2C_SMBUS_BLOCK_MAX,
 609                                               command, data->block,
 610                                               data->block[0] + 1);
 611                 break;
 612         default:
 613                 hid_warn(hdev, "Unsupported transaction %d\n", size);
 614                 return -EOPNOTSUPP;
 615         }
 616
 617         if (count < 0)
 618                 return count;
 619
 620         ret = hid_hw_power(hdev, PM_HINT_FULLON);
 621         if (ret < 0) {
 622                 hid_err(hdev, "power management error: %d\n", ret);
 623                 return ret;
 624         }
 625
 626         ret = cp2112_hid_output(hdev, buf, count, HID_OUTPUT_REPORT);
 627         if (ret < 0) {
 628                 hid_warn(hdev, "Error starting transaction: %d\n", ret);
 629                 goto power_normal;
 630         }
 631
 632         for (retries = 0; retries < XFER_STATUS_RETRIES; ++retries) {
 633                 ret = cp2112_xfer_status(dev);
 634                 if (-EBUSY == ret)
 635                         continue;
 636                 if (ret < 0)
 637                         goto power_normal;
 638                 break;
 639         }
 640
 641         if (XFER_STATUS_RETRIES <= retries) {
 642                 hid_warn(hdev, "Transfer timed out, cancelling.\n");
 643                 buf[0] = CP2112_CANCEL_TRANSFER;
 644                 buf[1] = 0x01;
 645
 646                 ret = cp2112_hid_output(hdev, buf, 2, HID_OUTPUT_REPORT);
 647                 if (ret < 0)
 648                         hid_warn(hdev, "Error cancelling transaction: %d\n",
 649                                  ret);
 650
 651                 ret = -ETIMEDOUT;
 652                 goto power_normal;
 653         }
 654
 655         if (I2C_SMBUS_WRITE == read_write) {
 656                 ret = 0;
 657                 goto power_normal;
 658         }
 659
 660         if (I2C_SMBUS_BLOCK_DATA == size)
 661                 read_length = ret;
 662
 663         ret = cp2112_read(dev, buf, read_length);
 664         if (ret < 0)
 665                 goto power_normal;
 666         if (ret != read_length) {
 667                 hid_warn(hdev, "short read: %d < %zd\n", ret, read_length);
 668                 ret = -EIO;
 669                 goto power_normal;
 670         }
 671
 672         switch (size) {
 673         case I2C_SMBUS_BYTE:
 674         case I2C_SMBUS_BYTE_DATA:
 675                 data->byte = buf[0];
 676                 break;
 677         case I2C_SMBUS_WORD_DATA:
 678                 data->word = le16_to_cpup((__le16 *)buf);
 679                 break;
 680         case I2C_SMBUS_BLOCK_DATA:
 681                 if (read_length > I2C_SMBUS_BLOCK_MAX) {
 682                         ret = -EPROTO;
 683                         goto power_normal;
 684                 }
 685
 686                 memcpy(data->block, buf, read_length);
 687                 break;
 688         }
 689
 690         ret = 0;
 691 power_normal:
 692         hid_hw_power(hdev, PM_HINT_NORMAL);
 693         hid_dbg(hdev, "transfer finished: %d\n", ret);
 694         return ret;
 695 }
 696
 697 static u32 cp2112_functionality(struct i2c_adapter *adap)
 698 {
 699         return I2C_FUNC_I2C |
 700                 I2C_FUNC_SMBUS_BYTE |
 701                 I2C_FUNC_SMBUS_BYTE_DATA |
 702                 I2C_FUNC_SMBUS_WORD_DATA |
 703                 I2C_FUNC_SMBUS_BLOCK_DATA |
 704                 I2C_FUNC_SMBUS_I2C_BLOCK |
 705                 I2C_FUNC_SMBUS_PROC_CALL |
 706                 I2C_FUNC_SMBUS_BLOCK_PROC_CALL;
 707 }
 708
 709 static const struct i2c_algorithm smbus_algorithm = {
 710         .master_xfer    = cp2112_i2c_xfer,
 711         .smbus_xfer     = cp2112_xfer,
 712         .functionality  = cp2112_functionality,
 713 };
 714
 715 static int cp2112_get_usb_config(struct hid_device *hdev,
 716                                  struct cp2112_usb_config_report *cfg)
 717 {
 718         int ret;
 719
 720         ret = cp2112_hid_get(hdev, CP2112_USB_CONFIG, (u8 *)cfg, sizeof(*cfg),
 721                              HID_FEATURE_REPORT);
 722         if (ret != sizeof(*cfg)) {
 723                 hid_err(hdev, "error reading usb config: %d\n", ret);
 724                 if (ret < 0)
 725                         return ret;
 726                 return -EIO;
 727         }
 728
 729         return 0;
 730 }
 731
 732 static int cp2112_set_usb_config(struct hid_device *hdev,
 733                                  struct cp2112_usb_config_report *cfg)
 734 {
 735         int ret;
 736
 737         BUG_ON(cfg->report != CP2112_USB_CONFIG);
 738
 739         ret = cp2112_hid_output(hdev, (u8 *)cfg, sizeof(*cfg),
 740                                 HID_FEATURE_REPORT);
 741         if (ret != sizeof(*cfg)) {
 742                 hid_err(hdev, "error writing usb config: %d\n", ret);
 743                 if (ret < 0)
 744                         return ret;
 745                 return -EIO;
 746         }
 747
 748         return 0;
 749 }
 750
 751 static void chmod_sysfs_attrs(struct hid_device *hdev);
 752
 753 #define CP2112_CONFIG_ATTR(name, store, format, ...) \
 754 static ssize_t name##_store(struct device *kdev, \
 755                             struct device_attribute *attr, const char *buf, \
 756                             size_t count) \
 757 { \
 758         struct hid_device *hdev = container_of(kdev, struct hid_device, dev); \
 759         struct cp2112_usb_config_report cfg; \
 760         int ret = cp2112_get_usb_config(hdev, &cfg); \
 761         if (ret) \
 762                 return ret; \
 763         store; \
 764         ret = cp2112_set_usb_config(hdev, &cfg); \
 765         if (ret) \
 766                 return ret; \
 767         chmod_sysfs_attrs(hdev); \
 768         return count; \
 769 } \
 770 static ssize_t name##_show(struct device *kdev, \
 771                            struct device_attribute *attr, char *buf) \
 772 { \
 773         struct hid_device *hdev = container_of(kdev, struct hid_device, dev); \
 774         struct cp2112_usb_config_report cfg; \
 775         int ret = cp2112_get_usb_config(hdev, &cfg); \
 776         if (ret) \
 777                 return ret; \
 778         return scnprintf(buf, PAGE_SIZE, format, ##__VA_ARGS__); \
 779 } \
 780 static DEVICE_ATTR_RW(name);
 781
 782 CP2112_CONFIG_ATTR(vendor_id, ({
 783         u16 vid;
 784
 785         if (sscanf(buf, "%hi", &vid) != 1)
 786                 return -EINVAL;
 787
 788         cfg.vid = cpu_to_le16(vid);
 789         cfg.mask = 0x01;
 790 }), "0x%04x\n", le16_to_cpu(cfg.vid));
 791
 792 CP2112_CONFIG_ATTR(product_id, ({
 793         u16 pid;
 794
 795         if (sscanf(buf, "%hi", &pid) != 1)
 796                 return -EINVAL;
 797
 798         cfg.pid = cpu_to_le16(pid);
 799         cfg.mask = 0x02;
 800 }), "0x%04x\n", le16_to_cpu(cfg.pid));
 801
 802 CP2112_CONFIG_ATTR(max_power, ({
 803         int mA;
 804
 805         if (sscanf(buf, "%i", &mA) != 1)
 806                 return -EINVAL;
 807
 808         cfg.max_power = (mA + 1) / 2;
 809         cfg.mask = 0x04;
 810 }), "%u mA\n", cfg.max_power * 2);
 811
 812 CP2112_CONFIG_ATTR(power_mode, ({
 813         if (sscanf(buf, "%hhi", &cfg.power_mode) != 1)
 814                 return -EINVAL;
 815
 816         cfg.mask = 0x08;
 817 }), "%u\n", cfg.power_mode);
 818
 819 CP2112_CONFIG_ATTR(release_version, ({
 820         if (sscanf(buf, "%hhi.%hhi", &cfg.release_major, &cfg.release_minor)
 821             != 2)
 822                 return -EINVAL;
 823
 824         cfg.mask = 0x10;
 825 }), "%u.%u\n", cfg.release_major, cfg.release_minor);
 826
 827 #undef CP2112_CONFIG_ATTR
 828
 829 struct cp2112_pstring_attribute {
 830         struct device_attribute attr;
 831         unsigned char report;
 832 };
 833
 834 static ssize_t pstr_store(struct device *kdev,
 835                           struct device_attribute *kattr, const char *buf,
 836                           size_t count)
 837 {
 838         struct hid_device *hdev = container_of(kdev, struct hid_device, dev);
 839         struct cp2112_pstring_attribute *attr =
 840                 container_of(kattr, struct cp2112_pstring_attribute, attr);
 841         struct cp2112_string_report report;
 842         int ret;
 843
 844         memset(&report, 0, sizeof(report));
 845
 846         ret = utf8s_to_utf16s(buf, count, UTF16_LITTLE_ENDIAN,
 847                               report.string, ARRAY_SIZE(report.string));
 848         report.report = attr->report;
 849         report.length = ret * sizeof(report.string[0]) + 2;
 850         report.type = USB_DT_STRING;
 851
 852         ret = cp2112_hid_output(hdev, &report.report, report.length + 1,
 853                                 HID_FEATURE_REPORT);
 854         if (ret != report.length + 1) {
 855                 hid_err(hdev, "error writing %s string: %d\n", kattr->attr.name,
 856                         ret);
 857                 if (ret < 0)
 858                         return ret;
 859                 return -EIO;
 860         }
 861
 862         chmod_sysfs_attrs(hdev);
 863         return count;
 864 }
 865
 866 static ssize_t pstr_show(struct device *kdev,
 867                          struct device_attribute *kattr, char *buf)
 868 {
 869         struct hid_device *hdev = container_of(kdev, struct hid_device, dev);
 870         struct cp2112_pstring_attribute *attr =
 871                 container_of(kattr, struct cp2112_pstring_attribute, attr);
 872         struct cp2112_string_report report;
 873         u8 length;
 874         int ret;
 875
 876         ret = cp2112_hid_get(hdev, attr->report, &report.report,
 877                              sizeof(report) - 1, HID_FEATURE_REPORT);
 878         if (ret < 3) {
 879                 hid_err(hdev, "error reading %s string: %d\n", kattr->attr.name,
 880                         ret);
 881                 if (ret < 0)
 882                         return ret;
 883                 return -EIO;
 884         }
 885
 886         if (report.length < 2) {
 887                 hid_err(hdev, "invalid %s string length: %d\n",
 888                         kattr->attr.name, report.length);
 889                 return -EIO;
 890         }
 891
 892         length = report.length > ret - 1 ? ret - 1 : report.length;
 893         length = (length - 2) / sizeof(report.string[0]);
 894         ret = utf16s_to_utf8s(report.string, length, UTF16_LITTLE_ENDIAN, buf,
 895                               PAGE_SIZE - 1);
 896         buf[ret++] = '\n';
 897         return ret;
 898 }
 899
 900 #define CP2112_PSTR_ATTR(name, _report) \
 901 static struct cp2112_pstring_attribute dev_attr_##name = { \
 902         .attr = __ATTR(name, (S_IWUSR | S_IRUGO), pstr_show, pstr_store), \
 903         .report = _report, \
 904 };
 905
 906 CP2112_PSTR_ATTR(manufacturer,  CP2112_MANUFACTURER_STRING);
 907 CP2112_PSTR_ATTR(product,       CP2112_PRODUCT_STRING);
 908 CP2112_PSTR_ATTR(serial,        CP2112_SERIAL_STRING);
 909
 910 #undef CP2112_PSTR_ATTR
 911
 912 static const struct attribute_group cp2112_attr_group = {
 913         .attrs = (struct attribute *[]){
 914                 &dev_attr_vendor_id.attr,
 915                 &dev_attr_product_id.attr,
 916                 &dev_attr_max_power.attr,
 917                 &dev_attr_power_mode.attr,
 918                 &dev_attr_release_version.attr,
 919                 &dev_attr_manufacturer.attr.attr,
 920                 &dev_attr_product.attr.attr,
 921                 &dev_attr_serial.attr.attr,
 922                 NULL
 923         }
 924 };
 925
 926 /* Chmoding our sysfs attributes is simply a way to expose which fields in the
 927  * PROM have already been programmed. We do not depend on this preventing
 928  * writing to these attributes since the CP2112 will simply ignore writes to
 929  * already-programmed fields. This is why there is no sense in fixing this
 930  * racy behaviour.
 931  */
 932 static void chmod_sysfs_attrs(struct hid_device *hdev)
 933 {
 934         struct attribute **attr;
 935         u8 buf[2];
 936         int ret;
 937
 938         ret = cp2112_hid_get(hdev, CP2112_LOCK_BYTE, buf, sizeof(buf),
 939                              HID_FEATURE_REPORT);
 940         if (ret != sizeof(buf)) {
 941                 hid_err(hdev, "error reading lock byte: %d\n", ret);
 942                 return;
 943         }
 944
 945         for (attr = cp2112_attr_group.attrs; *attr; ++attr) {
 946                 umode_t mode = (buf[1] & 1) ? S_IWUSR | S_IRUGO : S_IRUGO;
 947                 ret = sysfs_chmod_file(&hdev->dev.kobj, *attr, mode);
 948                 if (ret < 0)
 949                         hid_err(hdev, "error chmoding sysfs file %s\n",
 950                                 (*attr)->name);
 951                 buf[1] >>= 1;
 952         }
 953 }
 954
 955 static int cp2112_probe(struct hid_device *hdev, const struct hid_device_id *id)
 956 {
 957         struct cp2112_device *dev;
 958         u8 buf[3];
 959         struct cp2112_smbus_config_report config;
 960         int ret;
 961
 962         ret = hid_parse(hdev);
 963         if (ret) {
 964                 hid_err(hdev, "parse failed\n");
 965                 return ret;
 966         }
 967
 968         ret = hid_hw_start(hdev, HID_CONNECT_HIDRAW);
 969         if (ret) {
 970                 hid_err(hdev, "hw start failed\n");
 971                 return ret;
 972         }
 973
 974         ret = hid_hw_open(hdev);
 975         if (ret) {
 976                 hid_err(hdev, "hw open failed\n");
 977                 goto err_hid_stop;
 978         }
 979
 980         ret = hid_hw_power(hdev, PM_HINT_FULLON);
 981         if (ret < 0) {
 982                 hid_err(hdev, "power management error: %d\n", ret);
 983                 goto err_hid_close;
 984         }
 985
 986         ret = cp2112_hid_get(hdev, CP2112_GET_VERSION_INFO, buf, sizeof(buf),
 987                              HID_FEATURE_REPORT);
 988         if (ret != sizeof(buf)) {
 989                 hid_err(hdev, "error requesting version\n");
 990                 if (ret >= 0)
 991                         ret = -EIO;
 992                 goto err_power_normal;
 993         }
 994
 995         hid_info(hdev, "Part Number: 0x%02X Device Version: 0x%02X\n",
 996                  buf[1], buf[2]);
 997
 998         ret = cp2112_hid_get(hdev, CP2112_SMBUS_CONFIG, (u8 *)&config,
 999                              sizeof(config), HID_FEATURE_REPORT);
1000         if (ret != sizeof(config)) {
1001                 hid_err(hdev, "error requesting SMBus config\n");
1002                 if (ret >= 0)
1003                         ret = -EIO;
1004                 goto err_power_normal;
1005         }
1006
1007         config.retry_time = cpu_to_be16(1);
1008
1009         ret = cp2112_hid_output(hdev, (u8 *)&config, sizeof(config),
1010                                 HID_FEATURE_REPORT);
1011         if (ret != sizeof(config)) {
1012                 hid_err(hdev, "error setting SMBus config\n");
1013                 if (ret >= 0)
1014                         ret = -EIO;
1015                 goto err_power_normal;
1016         }
1017
1018         dev = kzalloc(sizeof(*dev), GFP_KERNEL);
1019         if (!dev) {
1020                 ret = -ENOMEM;
1021                 goto err_power_normal;
1022         }
1023
1024         hid_set_drvdata(hdev, (void *)dev);
1025         dev->hdev               = hdev;
1026         dev->adap.owner         = THIS_MODULE;
1027         dev->adap.class         = I2C_CLASS_HWMON;
1028         dev->adap.algo          = &smbus_algorithm;
1029         dev->adap.algo_data     = dev;
1030         dev->adap.dev.parent    = &hdev->dev;
1031         snprintf(dev->adap.name, sizeof(dev->adap.name),
1032                  "CP2112 SMBus Bridge on hiddev%d", hdev->minor);
1033         init_waitqueue_head(&dev->wait);
1034
1035         hid_device_io_start(hdev);
1036         ret = i2c_add_adapter(&dev->adap);
1037         hid_device_io_stop(hdev);
1038
1039         if (ret) {
1040                 hid_err(hdev, "error registering i2c adapter\n");
1041                 goto err_free_dev;
1042         }
1043
1044         hid_dbg(hdev, "adapter registered\n");
1045
1046         dev->gc.label                   = "cp2112_gpio";
1047         dev->gc.direction_input         = cp2112_gpio_direction_input;
1048         dev->gc.direction_output        = cp2112_gpio_direction_output;
1049         dev->gc.set                     = cp2112_gpio_set;
1050         dev->gc.get                     = cp2112_gpio_get;
1051         dev->gc.base                    = -1;
1052         dev->gc.ngpio                   = 8;
1053         dev->gc.can_sleep               = 1;
1054         dev->gc.dev                     = &hdev->dev;
1055
1056         ret = gpiochip_add(&dev->gc);
1057         if (ret < 0) {
1058                 hid_err(hdev, "error registering gpio chip\n");
1059                 goto err_free_i2c;
1060         }
1061
1062         ret = sysfs_create_group(&hdev->dev.kobj, &cp2112_attr_group);
1063         if (ret < 0) {
1064                 hid_err(hdev, "error creating sysfs attrs\n");
1065                 goto err_gpiochip_remove;
1066         }
1067
1068         chmod_sysfs_attrs(hdev);
1069         hid_hw_power(hdev, PM_HINT_NORMAL);
1070
1071         return ret;
1072
1073 err_gpiochip_remove:
1074         gpiochip_remove(&dev->gc);
1075 err_free_i2c:
1076         i2c_del_adapter(&dev->adap);
1077 err_free_dev:
1078         kfree(dev);
1079 err_power_normal:
1080         hid_hw_power(hdev, PM_HINT_NORMAL);
1081 err_hid_close:
1082         hid_hw_close(hdev);
1083 err_hid_stop:
1084         hid_hw_stop(hdev);
1085         return ret;
1086 }
1087
1088 static void cp2112_remove(struct hid_device *hdev)
1089 {
1090         struct cp2112_device *dev = hid_get_drvdata(hdev);
1091
1092         sysfs_remove_group(&hdev->dev.kobj, &cp2112_attr_group);
1093         gpiochip_remove(&dev->gc);
1094         i2c_del_adapter(&dev->adap);
1095         /* i2c_del_adapter has finished removing all i2c devices from our
1096          * adapter. Well behaved devices should no longer call our cp2112_xfer
1097          * and should have waited for any pending calls to finish. It has also
1098          * waited for device_unregister(&adap->dev) to complete. Therefore we
1099          * can safely free our struct cp2112_device.
1100          */
1101         hid_hw_close(hdev);
1102         hid_hw_stop(hdev);
1103         kfree(dev);
1104 }
1105
1106 static int cp2112_raw_event(struct hid_device *hdev, struct hid_report *report,
1107                             u8 *data, int size)
1108 {
1109         struct cp2112_device *dev = hid_get_drvdata(hdev);
1110         struct cp2112_xfer_status_report *xfer = (void *)data;
1111
1112         switch (data[0]) {
1113         case CP2112_TRANSFER_STATUS_RESPONSE:
1114                 hid_dbg(hdev, "xfer status: %02x %02x %04x %04x\n",
1115                         xfer->status0, xfer->status1,
1116                         be16_to_cpu(xfer->retries), be16_to_cpu(xfer->length));
1117
1118                 switch (xfer->status0) {
1119                 case STATUS0_IDLE:
1120                         dev->xfer_status = -EAGAIN;
1121                         break;
1122                 case STATUS0_BUSY:
1123                         dev->xfer_status = -EBUSY;
1124                         break;
1125                 case STATUS0_COMPLETE:
1126                         dev->xfer_status = be16_to_cpu(xfer->length);
1127                         break;
1128                 case STATUS0_ERROR:
1129                         switch (xfer->status1) {
1130                         case STATUS1_TIMEOUT_NACK:
1131                         case STATUS1_TIMEOUT_BUS:
1132                                 dev->xfer_status = -ETIMEDOUT;
1133                                 break;
1134                         default:
1135                                 dev->xfer_status = -EIO;
1136                                 break;
1137                         }
1138                         break;
1139                 default:
1140                         dev->xfer_status = -EINVAL;
1141                         break;
1142                 }
1143
1144                 atomic_set(&dev->xfer_avail, 1);
1145                 break;
1146         case CP2112_DATA_READ_RESPONSE:
1147                 hid_dbg(hdev, "read response: %02x %02x\n", data[1], data[2]);
1148
1149                 dev->read_length = data[2];
1150                 if (dev->read_length > sizeof(dev->read_data))
1151                         dev->read_length = sizeof(dev->read_data);
1152
1153                 memcpy(dev->read_data, &data[3], dev->read_length);
1154                 atomic_set(&dev->read_avail, 1);
1155                 break;
1156         default:
1157                 hid_err(hdev, "unknown report\n");
1158
1159                 return 0;
1160         }
1161
1162         wake_up_interruptible(&dev->wait);
1163         return 1;
1164 }
1165
1166 static struct hid_driver cp2112_driver = {
1167         .name           = "cp2112",
1168         .id_table       = cp2112_devices,
1169         .probe          = cp2112_probe,
1170         .remove         = cp2112_remove,
1171         .raw_event      = cp2112_raw_event,
1172 };
1173
1174 module_hid_driver(cp2112_driver);
1175 MODULE_DESCRIPTION("Silicon Labs HID USB to SMBus master bridge");
1176 MODULE_AUTHOR("David Barksdale <dbarksdale@uplogix.com>");
1177 MODULE_LICENSE("GPL");
1178