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/driver.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         u8 hwversion;
 160         int xfer_status;
 161         atomic_t read_avail;
 162         atomic_t xfer_avail;
 163         struct gpio_chip gc;
 164 };
 165
 166 static int gpio_push_pull = 0xFF;
 167 module_param(gpio_push_pull, int, S_IRUGO | S_IWUSR);
 168 MODULE_PARM_DESC(gpio_push_pull, "GPIO push-pull configuration bitmask");
 169
 170 static int cp2112_gpio_direction_input(struct gpio_chip *chip, unsigned offset)
 171 {
 172         struct cp2112_device *dev = gpiochip_get_data(chip);
 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 = gpiochip_get_data(chip);
 201         struct hid_device *hdev = dev->hdev;
 202         u8 buf[3];
 203         int ret;
 204
 205         buf[0] = CP2112_GPIO_SET;
 206         buf[1] = value ? 0xff : 0;
 207         buf[2] = 1 << offset;
 208
 209         ret = hid_hw_raw_request(hdev, CP2112_GPIO_SET, buf, sizeof(buf),
 210                                  HID_FEATURE_REPORT, HID_REQ_SET_REPORT);
 211         if (ret < 0)
 212                 hid_err(hdev, "error setting GPIO values: %d\n", ret);
 213 }
 214
 215 static int cp2112_gpio_get(struct gpio_chip *chip, unsigned offset)
 216 {
 217         struct cp2112_device *dev = gpiochip_get_data(chip);
 218         struct hid_device *hdev = dev->hdev;
 219         u8 buf[2];
 220         int ret;
 221
 222         ret = hid_hw_raw_request(hdev, CP2112_GPIO_GET, buf, sizeof(buf),
 223                                        HID_FEATURE_REPORT, HID_REQ_GET_REPORT);
 224         if (ret != sizeof(buf)) {
 225                 hid_err(hdev, "error requesting GPIO values: %d\n", ret);
 226                 return ret;
 227         }
 228
 229         return (buf[1] >> offset) & 1;
 230 }
 231
 232 static int cp2112_gpio_direction_output(struct gpio_chip *chip,
 233                                         unsigned offset, int value)
 234 {
 235         struct cp2112_device *dev = gpiochip_get_data(chip);
 236         struct hid_device *hdev = dev->hdev;
 237         u8 buf[5];
 238         int ret;
 239
 240         ret = hid_hw_raw_request(hdev, CP2112_GPIO_CONFIG, buf,
 241                                        sizeof(buf), HID_FEATURE_REPORT,
 242                                        HID_REQ_GET_REPORT);
 243         if (ret != sizeof(buf)) {
 244                 hid_err(hdev, "error requesting GPIO config: %d\n", ret);
 245                 return ret;
 246         }
 247
 248         buf[1] |= 1 << offset;
 249         buf[2] = gpio_push_pull;
 250
 251         ret = hid_hw_raw_request(hdev, CP2112_GPIO_CONFIG, buf, sizeof(buf),
 252                                  HID_FEATURE_REPORT, HID_REQ_SET_REPORT);
 253         if (ret < 0) {
 254                 hid_err(hdev, "error setting GPIO config: %d\n", ret);
 255                 return ret;
 256         }
 257
 258         /*
 259          * Set gpio value when output direction is already set,
 260          * as specified in AN495, Rev. 0.2, cpt. 4.4
 261          */
 262         cp2112_gpio_set(chip, offset, value);
 263
 264         return 0;
 265 }
 266
 267 static int cp2112_hid_get(struct hid_device *hdev, unsigned char report_number,
 268                           u8 *data, size_t count, unsigned char report_type)
 269 {
 270         u8 *buf;
 271         int ret;
 272
 273         buf = kmalloc(count, GFP_KERNEL);
 274         if (!buf)
 275                 return -ENOMEM;
 276
 277         ret = hid_hw_raw_request(hdev, report_number, buf, count,
 278                                        report_type, HID_REQ_GET_REPORT);
 279         memcpy(data, buf, count);
 280         kfree(buf);
 281         return ret;
 282 }
 283
 284 static int cp2112_hid_output(struct hid_device *hdev, u8 *data, size_t count,
 285                              unsigned char report_type)
 286 {
 287         u8 *buf;
 288         int ret;
 289
 290         buf = kmemdup(data, count, GFP_KERNEL);
 291         if (!buf)
 292                 return -ENOMEM;
 293
 294         if (report_type == HID_OUTPUT_REPORT)
 295                 ret = hid_hw_output_report(hdev, buf, count);
 296         else
 297                 ret = hid_hw_raw_request(hdev, buf[0], buf, count, report_type,
 298                                 HID_REQ_SET_REPORT);
 299
 300         kfree(buf);
 301         return ret;
 302 }
 303
 304 static int cp2112_wait(struct cp2112_device *dev, atomic_t *avail)
 305 {
 306         int ret = 0;
 307
 308         /* We have sent either a CP2112_TRANSFER_STATUS_REQUEST or a
 309          * CP2112_DATA_READ_FORCE_SEND and we are waiting for the response to
 310          * come in cp2112_raw_event or timeout. There will only be one of these
 311          * in flight at any one time. The timeout is extremely large and is a
 312          * last resort if the CP2112 has died. If we do timeout we don't expect
 313          * to receive the response which would cause data races, it's not like
 314          * we can do anything about it anyway.
 315          */
 316         ret = wait_event_interruptible_timeout(dev->wait,
 317                 atomic_read(avail), msecs_to_jiffies(RESPONSE_TIMEOUT));
 318         if (-ERESTARTSYS == ret)
 319                 return ret;
 320         if (!ret)
 321                 return -ETIMEDOUT;
 322
 323         atomic_set(avail, 0);
 324         return 0;
 325 }
 326
 327 static int cp2112_xfer_status(struct cp2112_device *dev)
 328 {
 329         struct hid_device *hdev = dev->hdev;
 330         u8 buf[2];
 331         int ret;
 332
 333         buf[0] = CP2112_TRANSFER_STATUS_REQUEST;
 334         buf[1] = 0x01;
 335         atomic_set(&dev->xfer_avail, 0);
 336
 337         ret = cp2112_hid_output(hdev, buf, 2, HID_OUTPUT_REPORT);
 338         if (ret < 0) {
 339                 hid_warn(hdev, "Error requesting status: %d\n", ret);
 340                 return ret;
 341         }
 342
 343         ret = cp2112_wait(dev, &dev->xfer_avail);
 344         if (ret)
 345                 return ret;
 346
 347         return dev->xfer_status;
 348 }
 349
 350 static int cp2112_read(struct cp2112_device *dev, u8 *data, size_t size)
 351 {
 352         struct hid_device *hdev = dev->hdev;
 353         struct cp2112_force_read_report report;
 354         int ret;
 355
 356         if (size > sizeof(dev->read_data))
 357                 size = sizeof(dev->read_data);
 358         report.report = CP2112_DATA_READ_FORCE_SEND;
 359         report.length = cpu_to_be16(size);
 360
 361         atomic_set(&dev->read_avail, 0);
 362
 363         ret = cp2112_hid_output(hdev, &report.report, sizeof(report),
 364                                 HID_OUTPUT_REPORT);
 365         if (ret < 0) {
 366                 hid_warn(hdev, "Error requesting data: %d\n", ret);
 367                 return ret;
 368         }
 369
 370         ret = cp2112_wait(dev, &dev->read_avail);
 371         if (ret)
 372                 return ret;
 373
 374         hid_dbg(hdev, "read %d of %zd bytes requested\n",
 375                 dev->read_length, size);
 376
 377         if (size > dev->read_length)
 378                 size = dev->read_length;
 379
 380         memcpy(data, dev->read_data, size);
 381         return dev->read_length;
 382 }
 383
 384 static int cp2112_read_req(void *buf, u8 slave_address, u16 length)
 385 {
 386         struct cp2112_read_req_report *report = buf;
 387
 388         if (length < 1 || length > 512)
 389                 return -EINVAL;
 390
 391         report->report = CP2112_DATA_READ_REQUEST;
 392         report->slave_address = slave_address << 1;
 393         report->length = cpu_to_be16(length);
 394         return sizeof(*report);
 395 }
 396
 397 static int cp2112_write_read_req(void *buf, u8 slave_address, u16 length,
 398                                  u8 command, u8 *data, u8 data_length)
 399 {
 400         struct cp2112_write_read_req_report *report = buf;
 401
 402         if (length < 1 || length > 512
 403             || data_length > sizeof(report->target_address) - 1)
 404                 return -EINVAL;
 405
 406         report->report = CP2112_DATA_WRITE_READ_REQUEST;
 407         report->slave_address = slave_address << 1;
 408         report->length = cpu_to_be16(length);
 409         report->target_address_length = data_length + 1;
 410         report->target_address[0] = command;
 411         memcpy(&report->target_address[1], data, data_length);
 412         return data_length + 6;
 413 }
 414
 415 static int cp2112_write_req(void *buf, u8 slave_address, u8 command, u8 *data,
 416                             u8 data_length)
 417 {
 418         struct cp2112_write_req_report *report = buf;
 419
 420         if (data_length > sizeof(report->data) - 1)
 421                 return -EINVAL;
 422
 423         report->report = CP2112_DATA_WRITE_REQUEST;
 424         report->slave_address = slave_address << 1;
 425         report->length = data_length + 1;
 426         report->data[0] = command;
 427         memcpy(&report->data[1], data, data_length);
 428         return data_length + 4;
 429 }
 430
 431 static int cp2112_i2c_write_req(void *buf, u8 slave_address, u8 *data,
 432                                 u8 data_length)
 433 {
 434         struct cp2112_write_req_report *report = buf;
 435
 436         if (data_length > sizeof(report->data))
 437                 return -EINVAL;
 438
 439         report->report = CP2112_DATA_WRITE_REQUEST;
 440         report->slave_address = slave_address << 1;
 441         report->length = data_length;
 442         memcpy(report->data, data, data_length);
 443         return data_length + 3;
 444 }
 445
 446 static int cp2112_i2c_write_read_req(void *buf, u8 slave_address,
 447                                      u8 *addr, int addr_length,
 448                                      int read_length)
 449 {
 450         struct cp2112_write_read_req_report *report = buf;
 451
 452         if (read_length < 1 || read_length > 512 ||
 453             addr_length > sizeof(report->target_address))
 454                 return -EINVAL;
 455
 456         report->report = CP2112_DATA_WRITE_READ_REQUEST;
 457         report->slave_address = slave_address << 1;
 458         report->length = cpu_to_be16(read_length);
 459         report->target_address_length = addr_length;
 460         memcpy(report->target_address, addr, addr_length);
 461         return addr_length + 5;
 462 }
 463
 464 static int cp2112_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
 465                            int num)
 466 {
 467         struct cp2112_device *dev = (struct cp2112_device *)adap->algo_data;
 468         struct hid_device *hdev = dev->hdev;
 469         u8 buf[64];
 470         ssize_t count;
 471         ssize_t read_length = 0;
 472         u8 *read_buf = NULL;
 473         unsigned int retries;
 474         int ret;
 475
 476         hid_dbg(hdev, "I2C %d messages\n", num);
 477
 478         if (num == 1) {
 479                 if (msgs->flags & I2C_M_RD) {
 480                         hid_dbg(hdev, "I2C read %#04x len %d\n",
 481                                 msgs->addr, msgs->len);
 482                         read_length = msgs->len;
 483                         read_buf = msgs->buf;
 484                         count = cp2112_read_req(buf, msgs->addr, msgs->len);
 485                 } else {
 486                         hid_dbg(hdev, "I2C write %#04x len %d\n",
 487                                 msgs->addr, msgs->len);
 488                         count = cp2112_i2c_write_req(buf, msgs->addr,
 489                                                      msgs->buf, msgs->len);
 490                 }
 491                 if (count < 0)
 492                         return count;
 493         } else if (dev->hwversion > 1 &&  /* no repeated start in rev 1 */
 494                    num == 2 &&
 495                    msgs[0].addr == msgs[1].addr &&
 496                    !(msgs[0].flags & I2C_M_RD) && (msgs[1].flags & I2C_M_RD)) {
 497                 hid_dbg(hdev, "I2C write-read %#04x wlen %d rlen %d\n",
 498                         msgs[0].addr, msgs[0].len, msgs[1].len);
 499                 read_length = msgs[1].len;
 500                 read_buf = msgs[1].buf;
 501                 count = cp2112_i2c_write_read_req(buf, msgs[0].addr,
 502                                 msgs[0].buf, msgs[0].len, msgs[1].len);
 503                 if (count < 0)
 504                         return count;
 505         } else {
 506                 hid_err(hdev,
 507                         "Multi-message I2C transactions not supported\n");
 508                 return -EOPNOTSUPP;
 509         }
 510
 511         ret = hid_hw_power(hdev, PM_HINT_FULLON);
 512         if (ret < 0) {
 513                 hid_err(hdev, "power management error: %d\n", ret);
 514                 return ret;
 515         }
 516
 517         ret = cp2112_hid_output(hdev, buf, count, HID_OUTPUT_REPORT);
 518         if (ret < 0) {
 519                 hid_warn(hdev, "Error starting transaction: %d\n", ret);
 520                 goto power_normal;
 521         }
 522
 523         for (retries = 0; retries < XFER_STATUS_RETRIES; ++retries) {
 524                 ret = cp2112_xfer_status(dev);
 525                 if (-EBUSY == ret)
 526                         continue;
 527                 if (ret < 0)
 528                         goto power_normal;
 529                 break;
 530         }
 531
 532         if (XFER_STATUS_RETRIES <= retries) {
 533                 hid_warn(hdev, "Transfer timed out, cancelling.\n");
 534                 buf[0] = CP2112_CANCEL_TRANSFER;
 535                 buf[1] = 0x01;
 536
 537                 ret = cp2112_hid_output(hdev, buf, 2, HID_OUTPUT_REPORT);
 538                 if (ret < 0)
 539                         hid_warn(hdev, "Error cancelling transaction: %d\n",
 540                                  ret);
 541
 542                 ret = -ETIMEDOUT;
 543                 goto power_normal;
 544         }
 545
 546         for (count = 0; count < read_length;) {
 547                 ret = cp2112_read(dev, read_buf + count, read_length - count);
 548                 if (ret < 0)
 549                         goto power_normal;
 550                 if (ret == 0) {
 551                         hid_err(hdev, "read returned 0\n");
 552                         ret = -EIO;
 553                         goto power_normal;
 554                 }
 555                 count += ret;
 556                 if (count > read_length) {
 557                         /*
 558                          * The hardware returned too much data.
 559                          * This is mostly harmless because cp2112_read()
 560                          * has a limit check so didn't overrun our
 561                          * buffer.  Nevertheless, we return an error
 562                          * because something is seriously wrong and
 563                          * it shouldn't go unnoticed.
 564                          */
 565                         hid_err(hdev, "long read: %d > %zd\n",
 566                                 ret, read_length - count + ret);
 567                         ret = -EIO;
 568                         goto power_normal;
 569                 }
 570         }
 571
 572         /* return the number of transferred messages */
 573         ret = num;
 574
 575 power_normal:
 576         hid_hw_power(hdev, PM_HINT_NORMAL);
 577         hid_dbg(hdev, "I2C transfer finished: %d\n", ret);
 578         return ret;
 579 }
 580
 581 static int cp2112_xfer(struct i2c_adapter *adap, u16 addr,
 582                        unsigned short flags, char read_write, u8 command,
 583                        int size, union i2c_smbus_data *data)
 584 {
 585         struct cp2112_device *dev = (struct cp2112_device *)adap->algo_data;
 586         struct hid_device *hdev = dev->hdev;
 587         u8 buf[64];
 588         __le16 word;
 589         ssize_t count;
 590         size_t read_length = 0;
 591         unsigned int retries;
 592         int ret;
 593
 594         hid_dbg(hdev, "%s addr 0x%x flags 0x%x cmd 0x%x size %d\n",
 595                 read_write == I2C_SMBUS_WRITE ? "write" : "read",
 596                 addr, flags, command, size);
 597
 598         switch (size) {
 599         case I2C_SMBUS_BYTE:
 600                 read_length = 1;
 601
 602                 if (I2C_SMBUS_READ == read_write)
 603                         count = cp2112_read_req(buf, addr, read_length);
 604                 else
 605                         count = cp2112_write_req(buf, addr, command, NULL,
 606                                                  0);
 607                 break;
 608         case I2C_SMBUS_BYTE_DATA:
 609                 read_length = 1;
 610
 611                 if (I2C_SMBUS_READ == read_write)
 612                         count = cp2112_write_read_req(buf, addr, read_length,
 613                                                       command, NULL, 0);
 614                 else
 615                         count = cp2112_write_req(buf, addr, command,
 616                                                  &data->byte, 1);
 617                 break;
 618         case I2C_SMBUS_WORD_DATA:
 619                 read_length = 2;
 620                 word = cpu_to_le16(data->word);
 621
 622                 if (I2C_SMBUS_READ == read_write)
 623                         count = cp2112_write_read_req(buf, addr, read_length,
 624                                                       command, NULL, 0);
 625                 else
 626                         count = cp2112_write_req(buf, addr, command,
 627                                                  (u8 *)&word, 2);
 628                 break;
 629         case I2C_SMBUS_PROC_CALL:
 630                 size = I2C_SMBUS_WORD_DATA;
 631                 read_write = I2C_SMBUS_READ;
 632                 read_length = 2;
 633                 word = cpu_to_le16(data->word);
 634
 635                 count = cp2112_write_read_req(buf, addr, read_length, command,
 636                                               (u8 *)&word, 2);
 637                 break;
 638         case I2C_SMBUS_I2C_BLOCK_DATA:
 639                 size = I2C_SMBUS_BLOCK_DATA;
 640                 /* fallthrough */
 641         case I2C_SMBUS_BLOCK_DATA:
 642                 if (I2C_SMBUS_READ == read_write) {
 643                         count = cp2112_write_read_req(buf, addr,
 644                                                       I2C_SMBUS_BLOCK_MAX,
 645                                                       command, NULL, 0);
 646                 } else {
 647                         count = cp2112_write_req(buf, addr, command,
 648                                                  data->block,
 649                                                  data->block[0] + 1);
 650                 }
 651                 break;
 652         case I2C_SMBUS_BLOCK_PROC_CALL:
 653                 size = I2C_SMBUS_BLOCK_DATA;
 654                 read_write = I2C_SMBUS_READ;
 655
 656                 count = cp2112_write_read_req(buf, addr, I2C_SMBUS_BLOCK_MAX,
 657                                               command, data->block,
 658                                               data->block[0] + 1);
 659                 break;
 660         default:
 661                 hid_warn(hdev, "Unsupported transaction %d\n", size);
 662                 return -EOPNOTSUPP;
 663         }
 664
 665         if (count < 0)
 666                 return count;
 667
 668         ret = hid_hw_power(hdev, PM_HINT_FULLON);
 669         if (ret < 0) {
 670                 hid_err(hdev, "power management error: %d\n", ret);
 671                 return ret;
 672         }
 673
 674         ret = cp2112_hid_output(hdev, buf, count, HID_OUTPUT_REPORT);
 675         if (ret < 0) {
 676                 hid_warn(hdev, "Error starting transaction: %d\n", ret);
 677                 goto power_normal;
 678         }
 679
 680         for (retries = 0; retries < XFER_STATUS_RETRIES; ++retries) {
 681                 ret = cp2112_xfer_status(dev);
 682                 if (-EBUSY == ret)
 683                         continue;
 684                 if (ret < 0)
 685                         goto power_normal;
 686                 break;
 687         }
 688
 689         if (XFER_STATUS_RETRIES <= retries) {
 690                 hid_warn(hdev, "Transfer timed out, cancelling.\n");
 691                 buf[0] = CP2112_CANCEL_TRANSFER;
 692                 buf[1] = 0x01;
 693
 694                 ret = cp2112_hid_output(hdev, buf, 2, HID_OUTPUT_REPORT);
 695                 if (ret < 0)
 696                         hid_warn(hdev, "Error cancelling transaction: %d\n",
 697                                  ret);
 698
 699                 ret = -ETIMEDOUT;
 700                 goto power_normal;
 701         }
 702
 703         if (I2C_SMBUS_WRITE == read_write) {
 704                 ret = 0;
 705                 goto power_normal;
 706         }
 707
 708         if (I2C_SMBUS_BLOCK_DATA == size)
 709                 read_length = ret;
 710
 711         ret = cp2112_read(dev, buf, read_length);
 712         if (ret < 0)
 713                 goto power_normal;
 714         if (ret != read_length) {
 715                 hid_warn(hdev, "short read: %d < %zd\n", ret, read_length);
 716                 ret = -EIO;
 717                 goto power_normal;
 718         }
 719
 720         switch (size) {
 721         case I2C_SMBUS_BYTE:
 722         case I2C_SMBUS_BYTE_DATA:
 723                 data->byte = buf[0];
 724                 break;
 725         case I2C_SMBUS_WORD_DATA:
 726                 data->word = le16_to_cpup((__le16 *)buf);
 727                 break;
 728         case I2C_SMBUS_BLOCK_DATA:
 729                 if (read_length > I2C_SMBUS_BLOCK_MAX) {
 730                         ret = -EPROTO;
 731                         goto power_normal;
 732                 }
 733
 734                 memcpy(data->block, buf, read_length);
 735                 break;
 736         }
 737
 738         ret = 0;
 739 power_normal:
 740         hid_hw_power(hdev, PM_HINT_NORMAL);
 741         hid_dbg(hdev, "transfer finished: %d\n", ret);
 742         return ret;
 743 }
 744
 745 static u32 cp2112_functionality(struct i2c_adapter *adap)
 746 {
 747         return I2C_FUNC_I2C |
 748                 I2C_FUNC_SMBUS_BYTE |
 749                 I2C_FUNC_SMBUS_BYTE_DATA |
 750                 I2C_FUNC_SMBUS_WORD_DATA |
 751                 I2C_FUNC_SMBUS_BLOCK_DATA |
 752                 I2C_FUNC_SMBUS_I2C_BLOCK |
 753                 I2C_FUNC_SMBUS_PROC_CALL |
 754                 I2C_FUNC_SMBUS_BLOCK_PROC_CALL;
 755 }
 756
 757 static const struct i2c_algorithm smbus_algorithm = {
 758         .master_xfer    = cp2112_i2c_xfer,
 759         .smbus_xfer     = cp2112_xfer,
 760         .functionality  = cp2112_functionality,
 761 };
 762
 763 static int cp2112_get_usb_config(struct hid_device *hdev,
 764                                  struct cp2112_usb_config_report *cfg)
 765 {
 766         int ret;
 767
 768         ret = cp2112_hid_get(hdev, CP2112_USB_CONFIG, (u8 *)cfg, sizeof(*cfg),
 769                              HID_FEATURE_REPORT);
 770         if (ret != sizeof(*cfg)) {
 771                 hid_err(hdev, "error reading usb config: %d\n", ret);
 772                 if (ret < 0)
 773                         return ret;
 774                 return -EIO;
 775         }
 776
 777         return 0;
 778 }
 779
 780 static int cp2112_set_usb_config(struct hid_device *hdev,
 781                                  struct cp2112_usb_config_report *cfg)
 782 {
 783         int ret;
 784
 785         BUG_ON(cfg->report != CP2112_USB_CONFIG);
 786
 787         ret = cp2112_hid_output(hdev, (u8 *)cfg, sizeof(*cfg),
 788                                 HID_FEATURE_REPORT);
 789         if (ret != sizeof(*cfg)) {
 790                 hid_err(hdev, "error writing usb config: %d\n", ret);
 791                 if (ret < 0)
 792                         return ret;
 793                 return -EIO;
 794         }
 795
 796         return 0;
 797 }
 798
 799 static void chmod_sysfs_attrs(struct hid_device *hdev);
 800
 801 #define CP2112_CONFIG_ATTR(name, store, format, ...) \
 802 static ssize_t name##_store(struct device *kdev, \
 803                             struct device_attribute *attr, const char *buf, \
 804                             size_t count) \
 805 { \
 806         struct hid_device *hdev = to_hid_device(kdev); \
 807         struct cp2112_usb_config_report cfg; \
 808         int ret = cp2112_get_usb_config(hdev, &cfg); \
 809         if (ret) \
 810                 return ret; \
 811         store; \
 812         ret = cp2112_set_usb_config(hdev, &cfg); \
 813         if (ret) \
 814                 return ret; \
 815         chmod_sysfs_attrs(hdev); \
 816         return count; \
 817 } \
 818 static ssize_t name##_show(struct device *kdev, \
 819                            struct device_attribute *attr, char *buf) \
 820 { \
 821         struct hid_device *hdev = to_hid_device(kdev); \
 822         struct cp2112_usb_config_report cfg; \
 823         int ret = cp2112_get_usb_config(hdev, &cfg); \
 824         if (ret) \
 825                 return ret; \
 826         return scnprintf(buf, PAGE_SIZE, format, ##__VA_ARGS__); \
 827 } \
 828 static DEVICE_ATTR_RW(name);
 829
 830 CP2112_CONFIG_ATTR(vendor_id, ({
 831         u16 vid;
 832
 833         if (sscanf(buf, "%hi", &vid) != 1)
 834                 return -EINVAL;
 835
 836         cfg.vid = cpu_to_le16(vid);
 837         cfg.mask = 0x01;
 838 }), "0x%04x\n", le16_to_cpu(cfg.vid));
 839
 840 CP2112_CONFIG_ATTR(product_id, ({
 841         u16 pid;
 842
 843         if (sscanf(buf, "%hi", &pid) != 1)
 844                 return -EINVAL;
 845
 846         cfg.pid = cpu_to_le16(pid);
 847         cfg.mask = 0x02;
 848 }), "0x%04x\n", le16_to_cpu(cfg.pid));
 849
 850 CP2112_CONFIG_ATTR(max_power, ({
 851         int mA;
 852
 853         if (sscanf(buf, "%i", &mA) != 1)
 854                 return -EINVAL;
 855
 856         cfg.max_power = (mA + 1) / 2;
 857         cfg.mask = 0x04;
 858 }), "%u mA\n", cfg.max_power * 2);
 859
 860 CP2112_CONFIG_ATTR(power_mode, ({
 861         if (sscanf(buf, "%hhi", &cfg.power_mode) != 1)
 862                 return -EINVAL;
 863
 864         cfg.mask = 0x08;
 865 }), "%u\n", cfg.power_mode);
 866
 867 CP2112_CONFIG_ATTR(release_version, ({
 868         if (sscanf(buf, "%hhi.%hhi", &cfg.release_major, &cfg.release_minor)
 869             != 2)
 870                 return -EINVAL;
 871
 872         cfg.mask = 0x10;
 873 }), "%u.%u\n", cfg.release_major, cfg.release_minor);
 874
 875 #undef CP2112_CONFIG_ATTR
 876
 877 struct cp2112_pstring_attribute {
 878         struct device_attribute attr;
 879         unsigned char report;
 880 };
 881
 882 static ssize_t pstr_store(struct device *kdev,
 883                           struct device_attribute *kattr, const char *buf,
 884                           size_t count)
 885 {
 886         struct hid_device *hdev = to_hid_device(kdev);
 887         struct cp2112_pstring_attribute *attr =
 888                 container_of(kattr, struct cp2112_pstring_attribute, attr);
 889         struct cp2112_string_report report;
 890         int ret;
 891
 892         memset(&report, 0, sizeof(report));
 893
 894         ret = utf8s_to_utf16s(buf, count, UTF16_LITTLE_ENDIAN,
 895                               report.string, ARRAY_SIZE(report.string));
 896         report.report = attr->report;
 897         report.length = ret * sizeof(report.string[0]) + 2;
 898         report.type = USB_DT_STRING;
 899
 900         ret = cp2112_hid_output(hdev, &report.report, report.length + 1,
 901                                 HID_FEATURE_REPORT);
 902         if (ret != report.length + 1) {
 903                 hid_err(hdev, "error writing %s string: %d\n", kattr->attr.name,
 904                         ret);
 905                 if (ret < 0)
 906                         return ret;
 907                 return -EIO;
 908         }
 909
 910         chmod_sysfs_attrs(hdev);
 911         return count;
 912 }
 913
 914 static ssize_t pstr_show(struct device *kdev,
 915                          struct device_attribute *kattr, char *buf)
 916 {
 917         struct hid_device *hdev = to_hid_device(kdev);
 918         struct cp2112_pstring_attribute *attr =
 919                 container_of(kattr, struct cp2112_pstring_attribute, attr);
 920         struct cp2112_string_report report;
 921         u8 length;
 922         int ret;
 923
 924         ret = cp2112_hid_get(hdev, attr->report, &report.report,
 925                              sizeof(report) - 1, HID_FEATURE_REPORT);
 926         if (ret < 3) {
 927                 hid_err(hdev, "error reading %s string: %d\n", kattr->attr.name,
 928                         ret);
 929                 if (ret < 0)
 930                         return ret;
 931                 return -EIO;
 932         }
 933
 934         if (report.length < 2) {
 935                 hid_err(hdev, "invalid %s string length: %d\n",
 936                         kattr->attr.name, report.length);
 937                 return -EIO;
 938         }
 939
 940         length = report.length > ret - 1 ? ret - 1 : report.length;
 941         length = (length - 2) / sizeof(report.string[0]);
 942         ret = utf16s_to_utf8s(report.string, length, UTF16_LITTLE_ENDIAN, buf,
 943                               PAGE_SIZE - 1);
 944         buf[ret++] = '\n';
 945         return ret;
 946 }
 947
 948 #define CP2112_PSTR_ATTR(name, _report) \
 949 static struct cp2112_pstring_attribute dev_attr_##name = { \
 950         .attr = __ATTR(name, (S_IWUSR | S_IRUGO), pstr_show, pstr_store), \
 951         .report = _report, \
 952 };
 953
 954 CP2112_PSTR_ATTR(manufacturer,  CP2112_MANUFACTURER_STRING);
 955 CP2112_PSTR_ATTR(product,       CP2112_PRODUCT_STRING);
 956 CP2112_PSTR_ATTR(serial,        CP2112_SERIAL_STRING);
 957
 958 #undef CP2112_PSTR_ATTR
 959
 960 static const struct attribute_group cp2112_attr_group = {
 961         .attrs = (struct attribute *[]){
 962                 &dev_attr_vendor_id.attr,
 963                 &dev_attr_product_id.attr,
 964                 &dev_attr_max_power.attr,
 965                 &dev_attr_power_mode.attr,
 966                 &dev_attr_release_version.attr,
 967                 &dev_attr_manufacturer.attr.attr,
 968                 &dev_attr_product.attr.attr,
 969                 &dev_attr_serial.attr.attr,
 970                 NULL
 971         }
 972 };
 973
 974 /* Chmoding our sysfs attributes is simply a way to expose which fields in the
 975  * PROM have already been programmed. We do not depend on this preventing
 976  * writing to these attributes since the CP2112 will simply ignore writes to
 977  * already-programmed fields. This is why there is no sense in fixing this
 978  * racy behaviour.
 979  */
 980 static void chmod_sysfs_attrs(struct hid_device *hdev)
 981 {
 982         struct attribute **attr;
 983         u8 buf[2];
 984         int ret;
 985
 986         ret = cp2112_hid_get(hdev, CP2112_LOCK_BYTE, buf, sizeof(buf),
 987                              HID_FEATURE_REPORT);
 988         if (ret != sizeof(buf)) {
 989                 hid_err(hdev, "error reading lock byte: %d\n", ret);
 990                 return;
 991         }
 992
 993         for (attr = cp2112_attr_group.attrs; *attr; ++attr) {
 994                 umode_t mode = (buf[1] & 1) ? S_IWUSR | S_IRUGO : S_IRUGO;
 995                 ret = sysfs_chmod_file(&hdev->dev.kobj, *attr, mode);
 996                 if (ret < 0)
 997                         hid_err(hdev, "error chmoding sysfs file %s\n",
 998                                 (*attr)->name);
 999                 buf[1] >>= 1;
1000         }
1001 }
1002
1003 static int cp2112_probe(struct hid_device *hdev, const struct hid_device_id *id)
1004 {
1005         struct cp2112_device *dev;
1006         u8 buf[3];
1007         struct cp2112_smbus_config_report config;
1008         int ret;
1009
1010         ret = hid_parse(hdev);
1011         if (ret) {
1012                 hid_err(hdev, "parse failed\n");
1013                 return ret;
1014         }
1015
1016         ret = hid_hw_start(hdev, HID_CONNECT_HIDRAW);
1017         if (ret) {
1018                 hid_err(hdev, "hw start failed\n");
1019                 return ret;
1020         }
1021
1022         ret = hid_hw_open(hdev);
1023         if (ret) {
1024                 hid_err(hdev, "hw open failed\n");
1025                 goto err_hid_stop;
1026         }
1027
1028         ret = hid_hw_power(hdev, PM_HINT_FULLON);
1029         if (ret < 0) {
1030                 hid_err(hdev, "power management error: %d\n", ret);
1031                 goto err_hid_close;
1032         }
1033
1034         ret = cp2112_hid_get(hdev, CP2112_GET_VERSION_INFO, buf, sizeof(buf),
1035                              HID_FEATURE_REPORT);
1036         if (ret != sizeof(buf)) {
1037                 hid_err(hdev, "error requesting version\n");
1038                 if (ret >= 0)
1039                         ret = -EIO;
1040                 goto err_power_normal;
1041         }
1042
1043         hid_info(hdev, "Part Number: 0x%02X Device Version: 0x%02X\n",
1044                  buf[1], buf[2]);
1045
1046         ret = cp2112_hid_get(hdev, CP2112_SMBUS_CONFIG, (u8 *)&config,
1047                              sizeof(config), HID_FEATURE_REPORT);
1048         if (ret != sizeof(config)) {
1049                 hid_err(hdev, "error requesting SMBus config\n");
1050                 if (ret >= 0)
1051                         ret = -EIO;
1052                 goto err_power_normal;
1053         }
1054
1055         config.retry_time = cpu_to_be16(1);
1056
1057         ret = cp2112_hid_output(hdev, (u8 *)&config, sizeof(config),
1058                                 HID_FEATURE_REPORT);
1059         if (ret != sizeof(config)) {
1060                 hid_err(hdev, "error setting SMBus config\n");
1061                 if (ret >= 0)
1062                         ret = -EIO;
1063                 goto err_power_normal;
1064         }
1065
1066         dev = kzalloc(sizeof(*dev), GFP_KERNEL);
1067         if (!dev) {
1068                 ret = -ENOMEM;
1069                 goto err_power_normal;
1070         }
1071
1072         hid_set_drvdata(hdev, (void *)dev);
1073         dev->hdev               = hdev;
1074         dev->adap.owner         = THIS_MODULE;
1075         dev->adap.class         = I2C_CLASS_HWMON;
1076         dev->adap.algo          = &smbus_algorithm;
1077         dev->adap.algo_data     = dev;
1078         dev->adap.dev.parent    = &hdev->dev;
1079         snprintf(dev->adap.name, sizeof(dev->adap.name),
1080                  "CP2112 SMBus Bridge on hiddev%d", hdev->minor);
1081         dev->hwversion = buf[2];
1082         init_waitqueue_head(&dev->wait);
1083
1084         hid_device_io_start(hdev);
1085         ret = i2c_add_adapter(&dev->adap);
1086         hid_device_io_stop(hdev);
1087
1088         if (ret) {
1089                 hid_err(hdev, "error registering i2c adapter\n");
1090                 goto err_free_dev;
1091         }
1092
1093         hid_dbg(hdev, "adapter registered\n");
1094
1095         dev->gc.label                   = "cp2112_gpio";
1096         dev->gc.direction_input         = cp2112_gpio_direction_input;
1097         dev->gc.direction_output        = cp2112_gpio_direction_output;
1098         dev->gc.set                     = cp2112_gpio_set;
1099         dev->gc.get                     = cp2112_gpio_get;
1100         dev->gc.base                    = -1;
1101         dev->gc.ngpio                   = 8;
1102         dev->gc.can_sleep               = 1;
1103         dev->gc.parent                  = &hdev->dev;
1104
1105         ret = gpiochip_add_data(&dev->gc, dev);
1106         if (ret < 0) {
1107                 hid_err(hdev, "error registering gpio chip\n");
1108                 goto err_free_i2c;
1109         }
1110
1111         ret = sysfs_create_group(&hdev->dev.kobj, &cp2112_attr_group);
1112         if (ret < 0) {
1113                 hid_err(hdev, "error creating sysfs attrs\n");
1114                 goto err_gpiochip_remove;
1115         }
1116
1117         chmod_sysfs_attrs(hdev);
1118         hid_hw_power(hdev, PM_HINT_NORMAL);
1119
1120         return ret;
1121
1122 err_gpiochip_remove:
1123         gpiochip_remove(&dev->gc);
1124 err_free_i2c:
1125         i2c_del_adapter(&dev->adap);
1126 err_free_dev:
1127         kfree(dev);
1128 err_power_normal:
1129         hid_hw_power(hdev, PM_HINT_NORMAL);
1130 err_hid_close:
1131         hid_hw_close(hdev);
1132 err_hid_stop:
1133         hid_hw_stop(hdev);
1134         return ret;
1135 }
1136
1137 static void cp2112_remove(struct hid_device *hdev)
1138 {
1139         struct cp2112_device *dev = hid_get_drvdata(hdev);
1140
1141         sysfs_remove_group(&hdev->dev.kobj, &cp2112_attr_group);
1142         gpiochip_remove(&dev->gc);
1143         i2c_del_adapter(&dev->adap);
1144         /* i2c_del_adapter has finished removing all i2c devices from our
1145          * adapter. Well behaved devices should no longer call our cp2112_xfer
1146          * and should have waited for any pending calls to finish. It has also
1147          * waited for device_unregister(&adap->dev) to complete. Therefore we
1148          * can safely free our struct cp2112_device.
1149          */
1150         hid_hw_close(hdev);
1151         hid_hw_stop(hdev);
1152         kfree(dev);
1153 }
1154
1155 static int cp2112_raw_event(struct hid_device *hdev, struct hid_report *report,
1156                             u8 *data, int size)
1157 {
1158         struct cp2112_device *dev = hid_get_drvdata(hdev);
1159         struct cp2112_xfer_status_report *xfer = (void *)data;
1160
1161         switch (data[0]) {
1162         case CP2112_TRANSFER_STATUS_RESPONSE:
1163                 hid_dbg(hdev, "xfer status: %02x %02x %04x %04x\n",
1164                         xfer->status0, xfer->status1,
1165                         be16_to_cpu(xfer->retries), be16_to_cpu(xfer->length));
1166
1167                 switch (xfer->status0) {
1168                 case STATUS0_IDLE:
1169                         dev->xfer_status = -EAGAIN;
1170                         break;
1171                 case STATUS0_BUSY:
1172                         dev->xfer_status = -EBUSY;
1173                         break;
1174                 case STATUS0_COMPLETE:
1175                         dev->xfer_status = be16_to_cpu(xfer->length);
1176                         break;
1177                 case STATUS0_ERROR:
1178                         switch (xfer->status1) {
1179                         case STATUS1_TIMEOUT_NACK:
1180                         case STATUS1_TIMEOUT_BUS:
1181                                 dev->xfer_status = -ETIMEDOUT;
1182                                 break;
1183                         default:
1184                                 dev->xfer_status = -EIO;
1185                                 break;
1186                         }
1187                         break;
1188                 default:
1189                         dev->xfer_status = -EINVAL;
1190                         break;
1191                 }
1192
1193                 atomic_set(&dev->xfer_avail, 1);
1194                 break;
1195         case CP2112_DATA_READ_RESPONSE:
1196                 hid_dbg(hdev, "read response: %02x %02x\n", data[1], data[2]);
1197
1198                 dev->read_length = data[2];
1199                 if (dev->read_length > sizeof(dev->read_data))
1200                         dev->read_length = sizeof(dev->read_data);
1201
1202                 memcpy(dev->read_data, &data[3], dev->read_length);
1203                 atomic_set(&dev->read_avail, 1);
1204                 break;
1205         default:
1206                 hid_err(hdev, "unknown report\n");
1207
1208                 return 0;
1209         }
1210
1211         wake_up_interruptible(&dev->wait);
1212         return 1;
1213 }
1214
1215 static struct hid_driver cp2112_driver = {
1216         .name           = "cp2112",
1217         .id_table       = cp2112_devices,
1218         .probe          = cp2112_probe,
1219         .remove         = cp2112_remove,
1220         .raw_event      = cp2112_raw_event,
1221 };
1222
1223 module_hid_driver(cp2112_driver);
1224 MODULE_DESCRIPTION("Silicon Labs HID USB to SMBus master bridge");
1225 MODULE_AUTHOR("David Barksdale <dbarksdale@uplogix.com>");
1226 MODULE_LICENSE("GPL");
1227