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 <[email protected]>
   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         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 = container_of(chip, struct cp2112_device,
 173                                                  gc);
 174         struct hid_device *hdev = dev->hdev;
 175         u8 buf[5];
 176         int ret;
 177
 178         ret = hid_hw_raw_request(hdev, CP2112_GPIO_CONFIG, buf,
 179                                        sizeof(buf), HID_FEATURE_REPORT,
 180                                        HID_REQ_GET_REPORT);
 181         if (ret != sizeof(buf)) {
 182                 hid_err(hdev, "error requesting GPIO config: %d\n", ret);
 183                 return ret;
 184         }
 185
 186         buf[1] &= ~(1 << offset);
 187         buf[2] = gpio_push_pull;
 188
 189         ret = hid_hw_raw_request(hdev, CP2112_GPIO_CONFIG, buf, sizeof(buf),
 190                                  HID_FEATURE_REPORT, HID_REQ_SET_REPORT);
 191         if (ret < 0) {
 192                 hid_err(hdev, "error setting GPIO config: %d\n", ret);
 193                 return ret;
 194         }
 195
 196         return 0;
 197 }
 198
 199 static void cp2112_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
 200 {
 201         struct cp2112_device *dev = container_of(chip, struct cp2112_device,
 202                                                  gc);
 203         struct hid_device *hdev = dev->hdev;
 204         u8 buf[3];
 205         int ret;
 206
 207         buf[0] = CP2112_GPIO_SET;
 208         buf[1] = value ? 0xff : 0;
 209         buf[2] = 1 << offset;
 210
 211         ret = hid_hw_raw_request(hdev, CP2112_GPIO_SET, buf, sizeof(buf),
 212                                  HID_FEATURE_REPORT, HID_REQ_SET_REPORT);
 213         if (ret < 0)
 214                 hid_err(hdev, "error setting GPIO values: %d\n", ret);
 215 }
 216
 217 static int cp2112_gpio_get(struct gpio_chip *chip, unsigned offset)
 218 {
 219         struct cp2112_device *dev = container_of(chip, struct cp2112_device,
 220                                                  gc);
 221         struct hid_device *hdev = dev->hdev;
 222         u8 buf[2];
 223         int ret;
 224
 225         ret = hid_hw_raw_request(hdev, CP2112_GPIO_GET, buf, sizeof(buf),
 226                                        HID_FEATURE_REPORT, HID_REQ_GET_REPORT);
 227         if (ret != sizeof(buf)) {
 228                 hid_err(hdev, "error requesting GPIO values: %d\n", ret);
 229                 return ret;
 230         }
 231
 232         return (buf[1] >> offset) & 1;
 233 }
 234
 235 static int cp2112_gpio_direction_output(struct gpio_chip *chip,
 236                                         unsigned offset, int value)
 237 {
 238         struct cp2112_device *dev = container_of(chip, struct cp2112_device,
 239                                                  gc);
 240         struct hid_device *hdev = dev->hdev;
 241         u8 buf[5];
 242         int ret;
 243
 244         ret = hid_hw_raw_request(hdev, CP2112_GPIO_CONFIG, buf,
 245                                        sizeof(buf), HID_FEATURE_REPORT,
 246                                        HID_REQ_GET_REPORT);
 247         if (ret != sizeof(buf)) {
 248                 hid_err(hdev, "error requesting GPIO config: %d\n", ret);
 249                 return ret;
 250         }
 251
 252         buf[1] |= 1 << offset;
 253         buf[2] = gpio_push_pull;
 254
 255         ret = hid_hw_raw_request(hdev, CP2112_GPIO_CONFIG, buf, sizeof(buf),
 256                                  HID_FEATURE_REPORT, HID_REQ_SET_REPORT);
 257         if (ret < 0) {
 258                 hid_err(hdev, "error setting GPIO config: %d\n", ret);
 259                 return ret;
 260         }
 261
 262         /*
 263          * Set gpio value when output direction is already set,
 264          * as specified in AN495, Rev. 0.2, cpt. 4.4
 265          */
 266         cp2112_gpio_set(chip, offset, value);
 267
 268         return 0;
 269 }
 270
 271 static int cp2112_hid_get(struct hid_device *hdev, unsigned char report_number,
 272                           u8 *data, size_t count, unsigned char report_type)
 273 {
 274         u8 *buf;
 275         int ret;
 276
 277         buf = kmalloc(count, GFP_KERNEL);
 278         if (!buf)
 279                 return -ENOMEM;
 280
 281         ret = hid_hw_raw_request(hdev, report_number, buf, count,
 282                                        report_type, HID_REQ_GET_REPORT);
 283         memcpy(data, buf, count);
 284         kfree(buf);
 285         return ret;
 286 }
 287
 288 static int cp2112_hid_output(struct hid_device *hdev, u8 *data, size_t count,
 289                              unsigned char report_type)
 290 {
 291         u8 *buf;
 292         int ret;
 293
 294         buf = kmemdup(data, count, GFP_KERNEL);
 295         if (!buf)
 296                 return -ENOMEM;
 297
 298         if (report_type == HID_OUTPUT_REPORT)
 299                 ret = hid_hw_output_report(hdev, buf, count);
 300         else
 301                 ret = hid_hw_raw_request(hdev, buf[0], buf, count, report_type,
 302                                 HID_REQ_SET_REPORT);
 303
 304         kfree(buf);
 305         return ret;
 306 }
 307
 308 static int cp2112_wait(struct cp2112_device *dev, atomic_t *avail)
 309 {
 310         int ret = 0;
 311
 312         /* We have sent either a CP2112_TRANSFER_STATUS_REQUEST or a
 313          * CP2112_DATA_READ_FORCE_SEND and we are waiting for the response to
 314          * come in cp2112_raw_event or timeout. There will only be one of these
 315          * in flight at any one time. The timeout is extremely large and is a
 316          * last resort if the CP2112 has died. If we do timeout we don't expect
 317          * to receive the response which would cause data races, it's not like
 318          * we can do anything about it anyway.
 319          */
 320         ret = wait_event_interruptible_timeout(dev->wait,
 321                 atomic_read(avail), msecs_to_jiffies(RESPONSE_TIMEOUT));
 322         if (-ERESTARTSYS == ret)
 323                 return ret;
 324         if (!ret)
 325                 return -ETIMEDOUT;
 326
 327         atomic_set(avail, 0);
 328         return 0;
 329 }
 330
 331 static int cp2112_xfer_status(struct cp2112_device *dev)
 332 {
 333         struct hid_device *hdev = dev->hdev;
 334         u8 buf[2];
 335         int ret;
 336
 337         buf[0] = CP2112_TRANSFER_STATUS_REQUEST;
 338         buf[1] = 0x01;
 339         atomic_set(&dev->xfer_avail, 0);
 340
 341         ret = cp2112_hid_output(hdev, buf, 2, HID_OUTPUT_REPORT);
 342         if (ret < 0) {
 343                 hid_warn(hdev, "Error requesting status: %d\n", ret);
 344                 return ret;
 345         }
 346
 347         ret = cp2112_wait(dev, &dev->xfer_avail);
 348         if (ret)
 349                 return ret;
 350
 351         return dev->xfer_status;
 352 }
 353
 354 static int cp2112_read(struct cp2112_device *dev, u8 *data, size_t size)
 355 {
 356         struct hid_device *hdev = dev->hdev;
 357         struct cp2112_force_read_report report;
 358         int ret;
 359
 360         if (size > sizeof(dev->read_data))
 361                 size = sizeof(dev->read_data);
 362         report.report = CP2112_DATA_READ_FORCE_SEND;
 363         report.length = cpu_to_be16(size);
 364
 365         atomic_set(&dev->read_avail, 0);
 366
 367         ret = cp2112_hid_output(hdev, &report.report, sizeof(report),
 368                                 HID_OUTPUT_REPORT);
 369         if (ret < 0) {
 370                 hid_warn(hdev, "Error requesting data: %d\n", ret);
 371                 return ret;
 372         }
 373
 374         ret = cp2112_wait(dev, &dev->read_avail);
 375         if (ret)
 376                 return ret;
 377
 378         hid_dbg(hdev, "read %d of %zd bytes requested\n",
 379                 dev->read_length, size);
 380
 381         if (size > dev->read_length)
 382                 size = dev->read_length;
 383
 384         memcpy(data, dev->read_data, size);
 385         return dev->read_length;
 386 }
 387
 388 static int cp2112_read_req(void *buf, u8 slave_address, u16 length)
 389 {
 390         struct cp2112_read_req_report *report = buf;
 391
 392         if (length < 1 || length > 512)
 393                 return -EINVAL;
 394
 395         report->report = CP2112_DATA_READ_REQUEST;
 396         report->slave_address = slave_address << 1;
 397         report->length = cpu_to_be16(length);
 398         return sizeof(*report);
 399 }
 400
 401 static int cp2112_write_read_req(void *buf, u8 slave_address, u16 length,
 402                                  u8 command, u8 *data, u8 data_length)
 403 {
 404         struct cp2112_write_read_req_report *report = buf;
 405
 406         if (length < 1 || length > 512
 407             || data_length > sizeof(report->target_address) - 1)
 408                 return -EINVAL;
 409
 410         report->report = CP2112_DATA_WRITE_READ_REQUEST;
 411         report->slave_address = slave_address << 1;
 412         report->length = cpu_to_be16(length);
 413         report->target_address_length = data_length + 1;
 414         report->target_address[0] = command;
 415         memcpy(&report->target_address[1], data, data_length);
 416         return data_length + 6;
 417 }
 418
 419 static int cp2112_write_req(void *buf, u8 slave_address, u8 command, u8 *data,
 420                             u8 data_length)
 421 {
 422         struct cp2112_write_req_report *report = buf;
 423
 424         if (data_length > sizeof(report->data) - 1)
 425                 return -EINVAL;
 426
 427         report->report = CP2112_DATA_WRITE_REQUEST;
 428         report->slave_address = slave_address << 1;
 429         report->length = data_length + 1;
 430         report->data[0] = command;
 431         memcpy(&report->data[1], data, data_length);
 432         return data_length + 4;
 433 }
 434
 435 static int cp2112_i2c_write_req(void *buf, u8 slave_address, u8 *data,
 436                                 u8 data_length)
 437 {
 438         struct cp2112_write_req_report *report = buf;
 439
 440         if (data_length > sizeof(report->data))
 441                 return -EINVAL;
 442
 443         report->report = CP2112_DATA_WRITE_REQUEST;
 444         report->slave_address = slave_address << 1;
 445         report->length = data_length;
 446         memcpy(report->data, data, data_length);
 447         return data_length + 3;
 448 }
 449
 450 static int cp2112_i2c_write_read_req(void *buf, u8 slave_address,
 451                                      u8 *addr, int addr_length,
 452                                      int read_length)
 453 {
 454         struct cp2112_write_read_req_report *report = buf;
 455
 456         if (read_length < 1 || read_length > 512 ||
 457             addr_length > sizeof(report->target_address))
 458                 return -EINVAL;
 459
 460         report->report = CP2112_DATA_WRITE_READ_REQUEST;
 461         report->slave_address = slave_address << 1;
 462         report->length = cpu_to_be16(read_length);
 463         report->target_address_length = addr_length;
 464         memcpy(report->target_address, addr, addr_length);
 465         return addr_length + 5;
 466 }
 467
 468 static int cp2112_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
 469                            int num)
 470 {
 471         struct cp2112_device *dev = (struct cp2112_device *)adap->algo_data;
 472         struct hid_device *hdev = dev->hdev;
 473         u8 buf[64];
 474         ssize_t count;
 475         ssize_t read_length = 0;
 476         u8 *read_buf = NULL;
 477         unsigned int retries;
 478         int ret;
 479
 480         hid_dbg(hdev, "I2C %d messages\n", num);
 481
 482         if (num == 1) {
 483                 if (msgs->flags & I2C_M_RD) {
 484                         hid_dbg(hdev, "I2C read %#04x len %d\n",
 485                                 msgs->addr, msgs->len);
 486                         read_length = msgs->len;
 487                         read_buf = msgs->buf;
 488                         count = cp2112_read_req(buf, msgs->addr, msgs->len);
 489                 } else {
 490                         hid_dbg(hdev, "I2C write %#04x len %d\n",
 491                                 msgs->addr, msgs->len);
 492                         count = cp2112_i2c_write_req(buf, msgs->addr,
 493                                                      msgs->buf, msgs->len);
 494                 }
 495                 if (count < 0)
 496                         return count;
 497         } else if (dev->hwversion > 1 &&  /* no repeated start in rev 1 */
 498                    num == 2 &&
 499                    msgs[0].addr == msgs[1].addr &&
 500                    !(msgs[0].flags & I2C_M_RD) && (msgs[1].flags & I2C_M_RD)) {
 501                 hid_dbg(hdev, "I2C write-read %#04x wlen %d rlen %d\n",
 502                         msgs[0].addr, msgs[0].len, msgs[1].len);
 503                 read_length = msgs[1].len;
 504                 read_buf = msgs[1].buf;
 505                 count = cp2112_i2c_write_read_req(buf, msgs[0].addr,
 506                                 msgs[0].buf, msgs[0].len, msgs[1].len);
 507                 if (count < 0)
 508                         return count;
 509         } else {
 510                 hid_err(hdev,
 511                         "Multi-message I2C transactions not supported\n");
 512                 return -EOPNOTSUPP;
 513         }
 514
 515         ret = hid_hw_power(hdev, PM_HINT_FULLON);
 516         if (ret < 0) {
 517                 hid_err(hdev, "power management error: %d\n", ret);
 518                 return ret;
 519         }
 520
 521         ret = cp2112_hid_output(hdev, buf, count, HID_OUTPUT_REPORT);
 522         if (ret < 0) {
 523                 hid_warn(hdev, "Error starting transaction: %d\n", ret);
 524                 goto power_normal;
 525         }
 526
 527         for (retries = 0; retries < XFER_STATUS_RETRIES; ++retries) {
 528                 ret = cp2112_xfer_status(dev);
 529                 if (-EBUSY == ret)
 530                         continue;
 531                 if (ret < 0)
 532                         goto power_normal;
 533                 break;
 534         }
 535
 536         if (XFER_STATUS_RETRIES <= retries) {
 537                 hid_warn(hdev, "Transfer timed out, cancelling.\n");
 538                 buf[0] = CP2112_CANCEL_TRANSFER;
 539                 buf[1] = 0x01;
 540
 541                 ret = cp2112_hid_output(hdev, buf, 2, HID_OUTPUT_REPORT);
 542                 if (ret < 0)
 543                         hid_warn(hdev, "Error cancelling transaction: %d\n",
 544                                  ret);
 545
 546                 ret = -ETIMEDOUT;
 547                 goto power_normal;
 548         }
 549
 550         for (count = 0; count < read_length;) {
 551                 ret = cp2112_read(dev, read_buf + count, read_length - count);
 552                 if (ret < 0)
 553                         goto power_normal;
 554                 if (ret == 0) {
 555                         hid_err(hdev, "read returned 0\n");
 556                         ret = -EIO;
 557                         goto power_normal;
 558                 }
 559                 count += ret;
 560                 if (count > read_length) {
 561                         /*
 562                          * The hardware returned too much data.
 563                          * This is mostly harmless because cp2112_read()
 564                          * has a limit check so didn't overrun our
 565                          * buffer.  Nevertheless, we return an error
 566                          * because something is seriously wrong and
 567                          * it shouldn't go unnoticed.
 568                          */
 569                         hid_err(hdev, "long read: %d > %zd\n",
 570                                 ret, read_length - count + ret);
 571                         ret = -EIO;
 572                         goto power_normal;
 573                 }
 574         }
 575
 576         /* return the number of transferred messages */
 577         ret = num;
 578
 579 power_normal:
 580         hid_hw_power(hdev, PM_HINT_NORMAL);
 581         hid_dbg(hdev, "I2C transfer finished: %d\n", ret);
 582         return ret;
 583 }
 584
 585 static int cp2112_xfer(struct i2c_adapter *adap, u16 addr,
 586                        unsigned short flags, char read_write, u8 command,
 587                        int size, union i2c_smbus_data *data)
 588 {
 589         struct cp2112_device *dev = (struct cp2112_device *)adap->algo_data;
 590         struct hid_device *hdev = dev->hdev;
 591         u8 buf[64];
 592         __le16 word;
 593         ssize_t count;
 594         size_t read_length = 0;
 595         unsigned int retries;
 596         int ret;
 597
 598         hid_dbg(hdev, "%s addr 0x%x flags 0x%x cmd 0x%x size %d\n",
 599                 read_write == I2C_SMBUS_WRITE ? "write" : "read",
 600                 addr, flags, command, size);
 601
 602         switch (size) {
 603         case I2C_SMBUS_BYTE:
 604                 read_length = 1;
 605
 606                 if (I2C_SMBUS_READ == read_write)
 607                         count = cp2112_read_req(buf, addr, read_length);
 608                 else
 609                         count = cp2112_write_req(buf, addr, command, NULL,
 610                                                  0);
 611                 break;
 612         case I2C_SMBUS_BYTE_DATA:
 613                 read_length = 1;
 614
 615                 if (I2C_SMBUS_READ == read_write)
 616                         count = cp2112_write_read_req(buf, addr, read_length,
 617                                                       command, NULL, 0);
 618                 else
 619                         count = cp2112_write_req(buf, addr, command,
 620                                                  &data->byte, 1);
 621                 break;
 622         case I2C_SMBUS_WORD_DATA:
 623                 read_length = 2;
 624                 word = cpu_to_le16(data->word);
 625
 626                 if (I2C_SMBUS_READ == read_write)
 627                         count = cp2112_write_read_req(buf, addr, read_length,
 628                                                       command, NULL, 0);
 629                 else
 630                         count = cp2112_write_req(buf, addr, command,
 631                                                  (u8 *)&word, 2);
 632                 break;
 633         case I2C_SMBUS_PROC_CALL:
 634                 size = I2C_SMBUS_WORD_DATA;
 635                 read_write = I2C_SMBUS_READ;
 636                 read_length = 2;
 637                 word = cpu_to_le16(data->word);
 638
 639                 count = cp2112_write_read_req(buf, addr, read_length, command,
 640                                               (u8 *)&word, 2);
 641                 break;
 642         case I2C_SMBUS_I2C_BLOCK_DATA:
 643                 size = I2C_SMBUS_BLOCK_DATA;
 644                 /* fallthrough */
 645         case I2C_SMBUS_BLOCK_DATA:
 646                 if (I2C_SMBUS_READ == read_write) {
 647                         count = cp2112_write_read_req(buf, addr,
 648                                                       I2C_SMBUS_BLOCK_MAX,
 649                                                       command, NULL, 0);
 650                 } else {
 651                         count = cp2112_write_req(buf, addr, command,
 652                                                  data->block,
 653                                                  data->block[0] + 1);
 654                 }
 655                 break;
 656         case I2C_SMBUS_BLOCK_PROC_CALL:
 657                 size = I2C_SMBUS_BLOCK_DATA;
 658                 read_write = I2C_SMBUS_READ;
 659
 660                 count = cp2112_write_read_req(buf, addr, I2C_SMBUS_BLOCK_MAX,
 661                                               command, data->block,
 662                                               data->block[0] + 1);
 663                 break;
 664         default:
 665                 hid_warn(hdev, "Unsupported transaction %d\n", size);
 666                 return -EOPNOTSUPP;
 667         }
 668
 669         if (count < 0)
 670                 return count;
 671
 672         ret = hid_hw_power(hdev, PM_HINT_FULLON);
 673         if (ret < 0) {
 674                 hid_err(hdev, "power management error: %d\n", ret);
 675                 return ret;
 676         }
 677
 678         ret = cp2112_hid_output(hdev, buf, count, HID_OUTPUT_REPORT);
 679         if (ret < 0) {
 680                 hid_warn(hdev, "Error starting transaction: %d\n", ret);
 681                 goto power_normal;
 682         }
 683
 684         for (retries = 0; retries < XFER_STATUS_RETRIES; ++retries) {
 685                 ret = cp2112_xfer_status(dev);
 686                 if (-EBUSY == ret)
 687                         continue;
 688                 if (ret < 0)
 689                         goto power_normal;
 690                 break;
 691         }
 692
 693         if (XFER_STATUS_RETRIES <= retries) {
 694                 hid_warn(hdev, "Transfer timed out, cancelling.\n");
 695                 buf[0] = CP2112_CANCEL_TRANSFER;
 696                 buf[1] = 0x01;
 697
 698                 ret = cp2112_hid_output(hdev, buf, 2, HID_OUTPUT_REPORT);
 699                 if (ret < 0)
 700                         hid_warn(hdev, "Error cancelling transaction: %d\n",
 701                                  ret);
 702
 703                 ret = -ETIMEDOUT;
 704                 goto power_normal;
 705         }
 706
 707         if (I2C_SMBUS_WRITE == read_write) {
 708                 ret = 0;
 709                 goto power_normal;
 710         }
 711
 712         if (I2C_SMBUS_BLOCK_DATA == size)
 713                 read_length = ret;
 714
 715         ret = cp2112_read(dev, buf, read_length);
 716         if (ret < 0)
 717                 goto power_normal;
 718         if (ret != read_length) {
 719                 hid_warn(hdev, "short read: %d < %zd\n", ret, read_length);
 720                 ret = -EIO;
 721                 goto power_normal;
 722         }
 723
 724         switch (size) {
 725         case I2C_SMBUS_BYTE:
 726         case I2C_SMBUS_BYTE_DATA:
 727                 data->byte = buf[0];
 728                 break;
 729         case I2C_SMBUS_WORD_DATA:
 730                 data->word = le16_to_cpup((__le16 *)buf);
 731                 break;
 732         case I2C_SMBUS_BLOCK_DATA:
 733                 if (read_length > I2C_SMBUS_BLOCK_MAX) {
 734                         ret = -EPROTO;
 735                         goto power_normal;
 736                 }
 737
 738                 memcpy(data->block, buf, read_length);
 739                 break;
 740         }
 741
 742         ret = 0;
 743 power_normal:
 744         hid_hw_power(hdev, PM_HINT_NORMAL);
 745         hid_dbg(hdev, "transfer finished: %d\n", ret);
 746         return ret;
 747 }
 748
 749 static u32 cp2112_functionality(struct i2c_adapter *adap)
 750 {
 751         return I2C_FUNC_I2C |
 752                 I2C_FUNC_SMBUS_BYTE |
 753                 I2C_FUNC_SMBUS_BYTE_DATA |
 754                 I2C_FUNC_SMBUS_WORD_DATA |
 755                 I2C_FUNC_SMBUS_BLOCK_DATA |
 756                 I2C_FUNC_SMBUS_I2C_BLOCK |
 757                 I2C_FUNC_SMBUS_PROC_CALL |
 758                 I2C_FUNC_SMBUS_BLOCK_PROC_CALL;
 759 }
 760
 761 static const struct i2c_algorithm smbus_algorithm = {
 762         .master_xfer    = cp2112_i2c_xfer,
 763         .smbus_xfer     = cp2112_xfer,
 764         .functionality  = cp2112_functionality,
 765 };
 766
 767 static int cp2112_get_usb_config(struct hid_device *hdev,
 768                                  struct cp2112_usb_config_report *cfg)
 769 {
 770         int ret;
 771
 772         ret = cp2112_hid_get(hdev, CP2112_USB_CONFIG, (u8 *)cfg, sizeof(*cfg),
 773                              HID_FEATURE_REPORT);
 774         if (ret != sizeof(*cfg)) {
 775                 hid_err(hdev, "error reading usb config: %d\n", ret);
 776                 if (ret < 0)
 777                         return ret;
 778                 return -EIO;
 779         }
 780
 781         return 0;
 782 }
 783
 784 static int cp2112_set_usb_config(struct hid_device *hdev,
 785                                  struct cp2112_usb_config_report *cfg)
 786 {
 787         int ret;
 788
 789         BUG_ON(cfg->report != CP2112_USB_CONFIG);
 790
 791         ret = cp2112_hid_output(hdev, (u8 *)cfg, sizeof(*cfg),
 792                                 HID_FEATURE_REPORT);
 793         if (ret != sizeof(*cfg)) {
 794                 hid_err(hdev, "error writing usb config: %d\n", ret);
 795                 if (ret < 0)
 796                         return ret;
 797                 return -EIO;
 798         }
 799
 800         return 0;
 801 }
 802
 803 static void chmod_sysfs_attrs(struct hid_device *hdev);
 804
 805 #define CP2112_CONFIG_ATTR(name, store, format, ...) \
 806 static ssize_t name##_store(struct device *kdev, \
 807                             struct device_attribute *attr, const char *buf, \
 808                             size_t count) \
 809 { \
 810         struct hid_device *hdev = container_of(kdev, struct hid_device, dev); \
 811         struct cp2112_usb_config_report cfg; \
 812         int ret = cp2112_get_usb_config(hdev, &cfg); \
 813         if (ret) \
 814                 return ret; \
 815         store; \
 816         ret = cp2112_set_usb_config(hdev, &cfg); \
 817         if (ret) \
 818                 return ret; \
 819         chmod_sysfs_attrs(hdev); \
 820         return count; \
 821 } \
 822 static ssize_t name##_show(struct device *kdev, \
 823                            struct device_attribute *attr, char *buf) \
 824 { \
 825         struct hid_device *hdev = container_of(kdev, struct hid_device, dev); \
 826         struct cp2112_usb_config_report cfg; \
 827         int ret = cp2112_get_usb_config(hdev, &cfg); \
 828         if (ret) \
 829                 return ret; \
 830         return scnprintf(buf, PAGE_SIZE, format, ##__VA_ARGS__); \
 831 } \
 832 static DEVICE_ATTR_RW(name);
 833
 834 CP2112_CONFIG_ATTR(vendor_id, ({
 835         u16 vid;
 836
 837         if (sscanf(buf, "%hi", &vid) != 1)
 838                 return -EINVAL;
 839
 840         cfg.vid = cpu_to_le16(vid);
 841         cfg.mask = 0x01;
 842 }), "0x%04x\n", le16_to_cpu(cfg.vid));
 843
 844 CP2112_CONFIG_ATTR(product_id, ({
 845         u16 pid;
 846
 847         if (sscanf(buf, "%hi", &pid) != 1)
 848                 return -EINVAL;
 849
 850         cfg.pid = cpu_to_le16(pid);
 851         cfg.mask = 0x02;
 852 }), "0x%04x\n", le16_to_cpu(cfg.pid));
 853
 854 CP2112_CONFIG_ATTR(max_power, ({
 855         int mA;
 856
 857         if (sscanf(buf, "%i", &mA) != 1)
 858                 return -EINVAL;
 859
 860         cfg.max_power = (mA + 1) / 2;
 861         cfg.mask = 0x04;
 862 }), "%u mA\n", cfg.max_power * 2);
 863
 864 CP2112_CONFIG_ATTR(power_mode, ({
 865         if (sscanf(buf, "%hhi", &cfg.power_mode) != 1)
 866                 return -EINVAL;
 867
 868         cfg.mask = 0x08;
 869 }), "%u\n", cfg.power_mode);
 870
 871 CP2112_CONFIG_ATTR(release_version, ({
 872         if (sscanf(buf, "%hhi.%hhi", &cfg.release_major, &cfg.release_minor)
 873             != 2)
 874                 return -EINVAL;
 875
 876         cfg.mask = 0x10;
 877 }), "%u.%u\n", cfg.release_major, cfg.release_minor);
 878
 879 #undef CP2112_CONFIG_ATTR
 880
 881 struct cp2112_pstring_attribute {
 882         struct device_attribute attr;
 883         unsigned char report;
 884 };
 885
 886 static ssize_t pstr_store(struct device *kdev,
 887                           struct device_attribute *kattr, const char *buf,
 888                           size_t count)
 889 {
 890         struct hid_device *hdev = container_of(kdev, struct hid_device, dev);
 891         struct cp2112_pstring_attribute *attr =
 892                 container_of(kattr, struct cp2112_pstring_attribute, attr);
 893         struct cp2112_string_report report;
 894         int ret;
 895
 896         memset(&report, 0, sizeof(report));
 897
 898         ret = utf8s_to_utf16s(buf, count, UTF16_LITTLE_ENDIAN,
 899                               report.string, ARRAY_SIZE(report.string));
 900         report.report = attr->report;
 901         report.length = ret * sizeof(report.string[0]) + 2;
 902         report.type = USB_DT_STRING;
 903
 904         ret = cp2112_hid_output(hdev, &report.report, report.length + 1,
 905                                 HID_FEATURE_REPORT);
 906         if (ret != report.length + 1) {
 907                 hid_err(hdev, "error writing %s string: %d\n", kattr->attr.name,
 908                         ret);
 909                 if (ret < 0)
 910                         return ret;
 911                 return -EIO;
 912         }
 913
 914         chmod_sysfs_attrs(hdev);
 915         return count;
 916 }
 917
 918 static ssize_t pstr_show(struct device *kdev,
 919                          struct device_attribute *kattr, char *buf)
 920 {
 921         struct hid_device *hdev = container_of(kdev, struct hid_device, dev);
 922         struct cp2112_pstring_attribute *attr =
 923                 container_of(kattr, struct cp2112_pstring_attribute, attr);
 924         struct cp2112_string_report report;
 925         u8 length;
 926         int ret;
 927
 928         ret = cp2112_hid_get(hdev, attr->report, &report.report,
 929                              sizeof(report) - 1, HID_FEATURE_REPORT);
 930         if (ret < 3) {
 931                 hid_err(hdev, "error reading %s string: %d\n", kattr->attr.name,
 932                         ret);
 933                 if (ret < 0)
 934                         return ret;
 935                 return -EIO;
 936         }
 937
 938         if (report.length < 2) {
 939                 hid_err(hdev, "invalid %s string length: %d\n",
 940                         kattr->attr.name, report.length);
 941                 return -EIO;
 942         }
 943
 944         length = report.length > ret - 1 ? ret - 1 : report.length;
 945         length = (length - 2) / sizeof(report.string[0]);
 946         ret = utf16s_to_utf8s(report.string, length, UTF16_LITTLE_ENDIAN, buf,
 947                               PAGE_SIZE - 1);
 948         buf[ret++] = '\n';
 949         return ret;
 950 }
 951
 952 #define CP2112_PSTR_ATTR(name, _report) \
 953 static struct cp2112_pstring_attribute dev_attr_##name = { \
 954         .attr = __ATTR(name, (S_IWUSR | S_IRUGO), pstr_show, pstr_store), \
 955         .report = _report, \
 956 };
 957
 958 CP2112_PSTR_ATTR(manufacturer,  CP2112_MANUFACTURER_STRING);
 959 CP2112_PSTR_ATTR(product,       CP2112_PRODUCT_STRING);
 960 CP2112_PSTR_ATTR(serial,        CP2112_SERIAL_STRING);
 961
 962 #undef CP2112_PSTR_ATTR
 963
 964 static const struct attribute_group cp2112_attr_group = {
 965         .attrs = (struct attribute *[]){
 966                 &dev_attr_vendor_id.attr,
 967                 &dev_attr_product_id.attr,
 968                 &dev_attr_max_power.attr,
 969                 &dev_attr_power_mode.attr,
 970                 &dev_attr_release_version.attr,
 971                 &dev_attr_manufacturer.attr.attr,
 972                 &dev_attr_product.attr.attr,
 973                 &dev_attr_serial.attr.attr,
 974                 NULL
 975         }
 976 };
 977
 978 /* Chmoding our sysfs attributes is simply a way to expose which fields in the
 979  * PROM have already been programmed. We do not depend on this preventing
 980  * writing to these attributes since the CP2112 will simply ignore writes to
 981  * already-programmed fields. This is why there is no sense in fixing this
 982  * racy behaviour.
 983  */
 984 static void chmod_sysfs_attrs(struct hid_device *hdev)
 985 {
 986         struct attribute **attr;
 987         u8 buf[2];
 988         int ret;
 989
 990         ret = cp2112_hid_get(hdev, CP2112_LOCK_BYTE, buf, sizeof(buf),
 991                              HID_FEATURE_REPORT);
 992         if (ret != sizeof(buf)) {
 993                 hid_err(hdev, "error reading lock byte: %d\n", ret);
 994                 return;
 995         }
 996
 997         for (attr = cp2112_attr_group.attrs; *attr; ++attr) {
 998                 umode_t mode = (buf[1] & 1) ? S_IWUSR | S_IRUGO : S_IRUGO;
 999                 ret = sysfs_chmod_file(&hdev->dev.kobj, *attr, mode);
1000                 if (ret < 0)
1001                         hid_err(hdev, "error chmoding sysfs file %s\n",
1002                                 (*attr)->name);
1003                 buf[1] >>= 1;
1004         }
1005 }
1006
1007 static int cp2112_probe(struct hid_device *hdev, const struct hid_device_id *id)
1008 {
1009         struct cp2112_device *dev;
1010         u8 buf[3];
1011         struct cp2112_smbus_config_report config;
1012         int ret;
1013
1014         ret = hid_parse(hdev);
1015         if (ret) {
1016                 hid_err(hdev, "parse failed\n");
1017                 return ret;
1018         }
1019
1020         ret = hid_hw_start(hdev, HID_CONNECT_HIDRAW);
1021         if (ret) {
1022                 hid_err(hdev, "hw start failed\n");
1023                 return ret;
1024         }
1025
1026         ret = hid_hw_open(hdev);
1027         if (ret) {
1028                 hid_err(hdev, "hw open failed\n");
1029                 goto err_hid_stop;
1030         }
1031
1032         ret = hid_hw_power(hdev, PM_HINT_FULLON);
1033         if (ret < 0) {
1034                 hid_err(hdev, "power management error: %d\n", ret);
1035                 goto err_hid_close;
1036         }
1037
1038         ret = cp2112_hid_get(hdev, CP2112_GET_VERSION_INFO, buf, sizeof(buf),
1039                              HID_FEATURE_REPORT);
1040         if (ret != sizeof(buf)) {
1041                 hid_err(hdev, "error requesting version\n");
1042                 if (ret >= 0)
1043                         ret = -EIO;
1044                 goto err_power_normal;
1045         }
1046
1047         hid_info(hdev, "Part Number: 0x%02X Device Version: 0x%02X\n",
1048                  buf[1], buf[2]);
1049
1050         ret = cp2112_hid_get(hdev, CP2112_SMBUS_CONFIG, (u8 *)&config,
1051                              sizeof(config), HID_FEATURE_REPORT);
1052         if (ret != sizeof(config)) {
1053                 hid_err(hdev, "error requesting SMBus config\n");
1054                 if (ret >= 0)
1055                         ret = -EIO;
1056                 goto err_power_normal;
1057         }
1058
1059         config.retry_time = cpu_to_be16(1);
1060
1061         ret = cp2112_hid_output(hdev, (u8 *)&config, sizeof(config),
1062                                 HID_FEATURE_REPORT);
1063         if (ret != sizeof(config)) {
1064                 hid_err(hdev, "error setting SMBus config\n");
1065                 if (ret >= 0)
1066                         ret = -EIO;
1067                 goto err_power_normal;
1068         }
1069
1070         dev = kzalloc(sizeof(*dev), GFP_KERNEL);
1071         if (!dev) {
1072                 ret = -ENOMEM;
1073                 goto err_power_normal;
1074         }
1075
1076         hid_set_drvdata(hdev, (void *)dev);
1077         dev->hdev               = hdev;
1078         dev->adap.owner         = THIS_MODULE;
1079         dev->adap.class         = I2C_CLASS_HWMON;
1080         dev->adap.algo          = &smbus_algorithm;
1081         dev->adap.algo_data     = dev;
1082         dev->adap.dev.parent    = &hdev->dev;
1083         snprintf(dev->adap.name, sizeof(dev->adap.name),
1084                  "CP2112 SMBus Bridge on hiddev%d", hdev->minor);
1085         dev->hwversion = buf[2];
1086         init_waitqueue_head(&dev->wait);
1087
1088         hid_device_io_start(hdev);
1089         ret = i2c_add_adapter(&dev->adap);
1090         hid_device_io_stop(hdev);
1091
1092         if (ret) {
1093                 hid_err(hdev, "error registering i2c adapter\n");
1094                 goto err_free_dev;
1095         }
1096
1097         hid_dbg(hdev, "adapter registered\n");
1098
1099         dev->gc.label                   = "cp2112_gpio";
1100         dev->gc.direction_input         = cp2112_gpio_direction_input;
1101         dev->gc.direction_output        = cp2112_gpio_direction_output;
1102         dev->gc.set                     = cp2112_gpio_set;
1103         dev->gc.get                     = cp2112_gpio_get;
1104         dev->gc.base                    = -1;
1105         dev->gc.ngpio                   = 8;
1106         dev->gc.can_sleep               = 1;
1107         dev->gc.dev                     = &hdev->dev;
1108
1109         ret = gpiochip_add(&dev->gc);
1110         if (ret < 0) {
1111                 hid_err(hdev, "error registering gpio chip\n");
1112                 goto err_free_i2c;
1113         }
1114
1115         ret = sysfs_create_group(&hdev->dev.kobj, &cp2112_attr_group);
1116         if (ret < 0) {
1117                 hid_err(hdev, "error creating sysfs attrs\n");
1118                 goto err_gpiochip_remove;
1119         }
1120
1121         chmod_sysfs_attrs(hdev);
1122         hid_hw_power(hdev, PM_HINT_NORMAL);
1123
1124         return ret;
1125
1126 err_gpiochip_remove:
1127         gpiochip_remove(&dev->gc);
1128 err_free_i2c:
1129         i2c_del_adapter(&dev->adap);
1130 err_free_dev:
1131         kfree(dev);
1132 err_power_normal:
1133         hid_hw_power(hdev, PM_HINT_NORMAL);
1134 err_hid_close:
1135         hid_hw_close(hdev);
1136 err_hid_stop:
1137         hid_hw_stop(hdev);
1138         return ret;
1139 }
1140
1141 static void cp2112_remove(struct hid_device *hdev)
1142 {
1143         struct cp2112_device *dev = hid_get_drvdata(hdev);
1144
1145         sysfs_remove_group(&hdev->dev.kobj, &cp2112_attr_group);
1146         gpiochip_remove(&dev->gc);
1147         i2c_del_adapter(&dev->adap);
1148         /* i2c_del_adapter has finished removing all i2c devices from our
1149          * adapter. Well behaved devices should no longer call our cp2112_xfer
1150          * and should have waited for any pending calls to finish. It has also
1151          * waited for device_unregister(&adap->dev) to complete. Therefore we
1152          * can safely free our struct cp2112_device.
1153          */
1154         hid_hw_close(hdev);
1155         hid_hw_stop(hdev);
1156         kfree(dev);
1157 }
1158
1159 static int cp2112_raw_event(struct hid_device *hdev, struct hid_report *report,
1160                             u8 *data, int size)
1161 {
1162         struct cp2112_device *dev = hid_get_drvdata(hdev);
1163         struct cp2112_xfer_status_report *xfer = (void *)data;
1164
1165         switch (data[0]) {
1166         case CP2112_TRANSFER_STATUS_RESPONSE:
1167                 hid_dbg(hdev, "xfer status: %02x %02x %04x %04x\n",
1168                         xfer->status0, xfer->status1,
1169                         be16_to_cpu(xfer->retries), be16_to_cpu(xfer->length));
1170
1171                 switch (xfer->status0) {
1172                 case STATUS0_IDLE:
1173                         dev->xfer_status = -EAGAIN;
1174                         break;
1175                 case STATUS0_BUSY:
1176                         dev->xfer_status = -EBUSY;
1177                         break;
1178                 case STATUS0_COMPLETE:
1179                         dev->xfer_status = be16_to_cpu(xfer->length);
1180                         break;
1181                 case STATUS0_ERROR:
1182                         switch (xfer->status1) {
1183                         case STATUS1_TIMEOUT_NACK:
1184                         case STATUS1_TIMEOUT_BUS:
1185                                 dev->xfer_status = -ETIMEDOUT;
1186                                 break;
1187                         default:
1188                                 dev->xfer_status = -EIO;
1189                                 break;
1190                         }
1191                         break;
1192                 default:
1193                         dev->xfer_status = -EINVAL;
1194                         break;
1195                 }
1196
1197                 atomic_set(&dev->xfer_avail, 1);
1198                 break;
1199         case CP2112_DATA_READ_RESPONSE:
1200                 hid_dbg(hdev, "read response: %02x %02x\n", data[1], data[2]);
1201
1202                 dev->read_length = data[2];
1203                 if (dev->read_length > sizeof(dev->read_data))
1204                         dev->read_length = sizeof(dev->read_data);
1205
1206                 memcpy(dev->read_data, &data[3], dev->read_length);
1207                 atomic_set(&dev->read_avail, 1);
1208                 break;
1209         default:
1210                 hid_err(hdev, "unknown report\n");
1211
1212                 return 0;
1213         }
1214
1215         wake_up_interruptible(&dev->wait);
1216         return 1;
1217 }
1218
1219 static struct hid_driver cp2112_driver = {
1220         .name           = "cp2112",
1221         .id_table       = cp2112_devices,
1222         .probe          = cp2112_probe,
1223         .remove         = cp2112_remove,
1224         .raw_event      = cp2112_raw_event,
1225 };
1226
1227 module_hid_driver(cp2112_driver);
1228 MODULE_DESCRIPTION("Silicon Labs HID USB to SMBus master bridge");
1229 MODULE_AUTHOR("David Barksdale <[email protected]>");
1230 MODULE_LICENSE("GPL");
1231