drivers/i2c/busses/i2c-diolan-u2c.c

   1 /*
   2  * Driver for the Diolan u2c-12 USB-I2C adapter
   3  *
   4  * Copyright (c) 2010-2011 Ericsson AB
   5  *
   6  * Derived from:
   7  *  i2c-tiny-usb.c
   8  *  Copyright (C) 2006-2007 Till Harbaum (Till@Harbaum.org)
   9  *
  10  * This program is free software; you can redistribute it and/or
  11  * modify it under the terms of the GNU General Public License as
  12  * published by the Free Software Foundation, version 2.
  13  */
  14
  15 #include <linux/kernel.h>
  16 #include <linux/errno.h>
  17 #include <linux/module.h>
  18 #include <linux/types.h>
  19 #include <linux/slab.h>
  20 #include <linux/usb.h>
  21 #include <linux/i2c.h>
  22
  23 #define DRIVER_NAME             "i2c-diolan-u2c"
  24
  25 #define USB_VENDOR_ID_DIOLAN            0x0abf
  26 #define USB_DEVICE_ID_DIOLAN_U2C        0x3370
  27
  28 #define DIOLAN_OUT_EP           0x02
  29 #define DIOLAN_IN_EP            0x84
  30
  31 /* commands via USB, must match command ids in the firmware */
  32 #define CMD_I2C_READ            0x01
  33 #define CMD_I2C_WRITE           0x02
  34 #define CMD_I2C_SCAN            0x03    /* Returns list of detected devices */
  35 #define CMD_I2C_RELEASE_SDA     0x04
  36 #define CMD_I2C_RELEASE_SCL     0x05
  37 #define CMD_I2C_DROP_SDA        0x06
  38 #define CMD_I2C_DROP_SCL        0x07
  39 #define CMD_I2C_READ_SDA        0x08
  40 #define CMD_I2C_READ_SCL        0x09
  41 #define CMD_GET_FW_VERSION      0x0a
  42 #define CMD_GET_SERIAL          0x0b
  43 #define CMD_I2C_START           0x0c
  44 #define CMD_I2C_STOP            0x0d
  45 #define CMD_I2C_REPEATED_START  0x0e
  46 #define CMD_I2C_PUT_BYTE        0x0f
  47 #define CMD_I2C_GET_BYTE        0x10
  48 #define CMD_I2C_PUT_ACK         0x11
  49 #define CMD_I2C_GET_ACK         0x12
  50 #define CMD_I2C_PUT_BYTE_ACK    0x13
  51 #define CMD_I2C_GET_BYTE_ACK    0x14
  52 #define CMD_I2C_SET_SPEED       0x1b
  53 #define CMD_I2C_GET_SPEED       0x1c
  54 #define CMD_I2C_SET_CLK_SYNC    0x24
  55 #define CMD_I2C_GET_CLK_SYNC    0x25
  56 #define CMD_I2C_SET_CLK_SYNC_TO 0x26
  57 #define CMD_I2C_GET_CLK_SYNC_TO 0x27
  58
  59 #define RESP_OK                 0x00
  60 #define RESP_FAILED             0x01
  61 #define RESP_BAD_MEMADDR        0x04
  62 #define RESP_DATA_ERR           0x05
  63 #define RESP_NOT_IMPLEMENTED    0x06
  64 #define RESP_NACK               0x07
  65 #define RESP_TIMEOUT            0x09
  66
  67 #define U2C_I2C_SPEED_FAST      0       /* 400 kHz */
  68 #define U2C_I2C_SPEED_STD       1       /* 100 kHz */
  69 #define U2C_I2C_SPEED_2KHZ      242     /* 2 kHz, minimum speed */
  70 #define U2C_I2C_SPEED(f)        ((DIV_ROUND_UP(1000000, (f)) - 10) / 2 + 1)
  71
  72 #define U2C_I2C_FREQ_FAST       400000
  73 #define U2C_I2C_FREQ_STD        100000
  74 #define U2C_I2C_FREQ(s)         (1000000 / (2 * (s - 1) + 10))
  75
  76 #define DIOLAN_USB_TIMEOUT      100     /* in ms */
  77 #define DIOLAN_SYNC_TIMEOUT     20      /* in ms */
  78
  79 #define DIOLAN_OUTBUF_LEN       128
  80 #define DIOLAN_FLUSH_LEN        (DIOLAN_OUTBUF_LEN - 4)
  81 #define DIOLAN_INBUF_LEN        256     /* Maximum supported receive length */
  82
  83 /* Structure to hold all of our device specific stuff */
  84 struct i2c_diolan_u2c {
  85         u8 obuffer[DIOLAN_OUTBUF_LEN];  /* output buffer */
  86         u8 ibuffer[DIOLAN_INBUF_LEN];   /* input buffer */
  87         struct usb_device *usb_dev;     /* the usb device for this device */
  88         struct usb_interface *interface;/* the interface for this device */
  89         struct i2c_adapter adapter;     /* i2c related things */
  90         int olen;                       /* Output buffer length */
  91         int ocount;                     /* Number of enqueued messages */
  92 };
  93
  94 static uint frequency = U2C_I2C_FREQ_STD;       /* I2C clock frequency in Hz */
  95
  96 module_param(frequency, uint, S_IRUGO | S_IWUSR);
  97 MODULE_PARM_DESC(frequency, "I2C clock frequency in hertz");
  98
  99 /* usb layer */
 100
 101 /* Send command to device, and get response. */
 102 static int diolan_usb_transfer(struct i2c_diolan_u2c *dev)
 103 {
 104         int ret = 0;
 105         int actual;
 106         int i;
 107
 108         if (!dev->olen || !dev->ocount)
 109                 return -EINVAL;
 110
 111         ret = usb_bulk_msg(dev->usb_dev,
 112                            usb_sndbulkpipe(dev->usb_dev, DIOLAN_OUT_EP),
 113                            dev->obuffer, dev->olen, &actual,
 114                            DIOLAN_USB_TIMEOUT);
 115         if (!ret) {
 116                 for (i = 0; i < dev->ocount; i++) {
 117                         int tmpret;
 118
 119                         tmpret = usb_bulk_msg(dev->usb_dev,
 120                                               usb_rcvbulkpipe(dev->usb_dev,
 121                                                               DIOLAN_IN_EP),
 122                                               dev->ibuffer,
 123                                               sizeof(dev->ibuffer), &actual,
 124                                               DIOLAN_USB_TIMEOUT);
 125                         /*
 126                          * Stop command processing if a previous command
 127                          * returned an error.
 128                          * Note that we still need to retrieve all messages.
 129                          */
 130                         if (ret < 0)
 131                                 continue;
 132                         ret = tmpret;
 133                         if (ret == 0 && actual > 0) {
 134                                 switch (dev->ibuffer[actual - 1]) {
 135                                 case RESP_NACK:
 136                                         /*
 137                                          * Return ENXIO if NACK was received as
 138                                          * response to the address phase,
 139                                          * EIO otherwise
 140                                          */
 141                                         ret = i == 1 ? -ENXIO : -EIO;
 142                                         break;
 143                                 case RESP_TIMEOUT:
 144                                         ret = -ETIMEDOUT;
 145                                         break;
 146                                 case RESP_OK:
 147                                         /* strip off return code */
 148                                         ret = actual - 1;
 149                                         break;
 150                                 default:
 151                                         ret = -EIO;
 152                                         break;
 153                                 }
 154                         }
 155                 }
 156         }
 157         dev->olen = 0;
 158         dev->ocount = 0;
 159         return ret;
 160 }
 161
 162 static int diolan_write_cmd(struct i2c_diolan_u2c *dev, bool flush)
 163 {
 164         if (flush || dev->olen >= DIOLAN_FLUSH_LEN)
 165                 return diolan_usb_transfer(dev);
 166         return 0;
 167 }
 168
 169 /* Send command (no data) */
 170 static int diolan_usb_cmd(struct i2c_diolan_u2c *dev, u8 command, bool flush)
 171 {
 172         dev->obuffer[dev->olen++] = command;
 173         dev->ocount++;
 174         return diolan_write_cmd(dev, flush);
 175 }
 176
 177 /* Send command with one byte of data */
 178 static int diolan_usb_cmd_data(struct i2c_diolan_u2c *dev, u8 command, u8 data,
 179                                bool flush)
 180 {
 181         dev->obuffer[dev->olen++] = command;
 182         dev->obuffer[dev->olen++] = data;
 183         dev->ocount++;
 184         return diolan_write_cmd(dev, flush);
 185 }
 186
 187 /* Send command with two bytes of data */
 188 static int diolan_usb_cmd_data2(struct i2c_diolan_u2c *dev, u8 command, u8 d1,
 189                                 u8 d2, bool flush)
 190 {
 191         dev->obuffer[dev->olen++] = command;
 192         dev->obuffer[dev->olen++] = d1;
 193         dev->obuffer[dev->olen++] = d2;
 194         dev->ocount++;
 195         return diolan_write_cmd(dev, flush);
 196 }
 197
 198 /*
 199  * Flush input queue.
 200  * If we don't do this at startup and the controller has queued up
 201  * messages which were not retrieved, it will stop responding
 202  * at some point.
 203  */
 204 static void diolan_flush_input(struct i2c_diolan_u2c *dev)
 205 {
 206         int i;
 207
 208         for (i = 0; i < 10; i++) {
 209                 int actual = 0;
 210                 int ret;
 211
 212                 ret = usb_bulk_msg(dev->usb_dev,
 213                                    usb_rcvbulkpipe(dev->usb_dev, DIOLAN_IN_EP),
 214                                    dev->ibuffer, sizeof(dev->ibuffer), &actual,
 215                                    DIOLAN_USB_TIMEOUT);
 216                 if (ret < 0 || actual == 0)
 217                         break;
 218         }
 219         if (i == 10)
 220                 dev_err(&dev->interface->dev, "Failed to flush input buffer\n");
 221 }
 222
 223 static int diolan_i2c_start(struct i2c_diolan_u2c *dev)
 224 {
 225         return diolan_usb_cmd(dev, CMD_I2C_START, false);
 226 }
 227
 228 static int diolan_i2c_repeated_start(struct i2c_diolan_u2c *dev)
 229 {
 230         return diolan_usb_cmd(dev, CMD_I2C_REPEATED_START, false);
 231 }
 232
 233 static int diolan_i2c_stop(struct i2c_diolan_u2c *dev)
 234 {
 235         return diolan_usb_cmd(dev, CMD_I2C_STOP, true);
 236 }
 237
 238 static int diolan_i2c_get_byte_ack(struct i2c_diolan_u2c *dev, bool ack,
 239                                    u8 *byte)
 240 {
 241         int ret;
 242
 243         ret = diolan_usb_cmd_data(dev, CMD_I2C_GET_BYTE_ACK, ack, true);
 244         if (ret > 0)
 245                 *byte = dev->ibuffer[0];
 246         else if (ret == 0)
 247                 ret = -EIO;
 248
 249         return ret;
 250 }
 251
 252 static int diolan_i2c_put_byte_ack(struct i2c_diolan_u2c *dev, u8 byte)
 253 {
 254         return diolan_usb_cmd_data(dev, CMD_I2C_PUT_BYTE_ACK, byte, false);
 255 }
 256
 257 static int diolan_set_speed(struct i2c_diolan_u2c *dev, u8 speed)
 258 {
 259         return diolan_usb_cmd_data(dev, CMD_I2C_SET_SPEED, speed, true);
 260 }
 261
 262 /* Enable or disable clock synchronization (stretching) */
 263 static int diolan_set_clock_synch(struct i2c_diolan_u2c *dev, bool enable)
 264 {
 265         return diolan_usb_cmd_data(dev, CMD_I2C_SET_CLK_SYNC, enable, true);
 266 }
 267
 268 /* Set clock synchronization timeout in ms */
 269 static int diolan_set_clock_synch_timeout(struct i2c_diolan_u2c *dev, int ms)
 270 {
 271         int to_val = ms * 10;
 272
 273         return diolan_usb_cmd_data2(dev, CMD_I2C_SET_CLK_SYNC_TO,
 274                                     to_val & 0xff, (to_val >> 8) & 0xff, true);
 275 }
 276
 277 static void diolan_fw_version(struct i2c_diolan_u2c *dev)
 278 {
 279         int ret;
 280
 281         ret = diolan_usb_cmd(dev, CMD_GET_FW_VERSION, true);
 282         if (ret >= 2)
 283                 dev_info(&dev->interface->dev,
 284                          "Diolan U2C firmware version %u.%u\n",
 285                          (unsigned int)dev->ibuffer[0],
 286                          (unsigned int)dev->ibuffer[1]);
 287 }
 288
 289 static void diolan_get_serial(struct i2c_diolan_u2c *dev)
 290 {
 291         int ret;
 292         u32 serial;
 293
 294         ret = diolan_usb_cmd(dev, CMD_GET_SERIAL, true);
 295         if (ret >= 4) {
 296                 serial = le32_to_cpu(*(u32 *)dev->ibuffer);
 297                 dev_info(&dev->interface->dev,
 298                          "Diolan U2C serial number %u\n", serial);
 299         }
 300 }
 301
 302 static int diolan_init(struct i2c_diolan_u2c *dev)
 303 {
 304         int speed, ret;
 305
 306         if (frequency >= 200000) {
 307                 speed = U2C_I2C_SPEED_FAST;
 308                 frequency = U2C_I2C_FREQ_FAST;
 309         } else if (frequency >= 100000 || frequency == 0) {
 310                 speed = U2C_I2C_SPEED_STD;
 311                 frequency = U2C_I2C_FREQ_STD;
 312         } else {
 313                 speed = U2C_I2C_SPEED(frequency);
 314                 if (speed > U2C_I2C_SPEED_2KHZ)
 315                         speed = U2C_I2C_SPEED_2KHZ;
 316                 frequency = U2C_I2C_FREQ(speed);
 317         }
 318
 319         dev_info(&dev->interface->dev,
 320                  "Diolan U2C at USB bus %03d address %03d speed %d Hz\n",
 321                  dev->usb_dev->bus->busnum, dev->usb_dev->devnum, frequency);
 322
 323         diolan_flush_input(dev);
 324         diolan_fw_version(dev);
 325         diolan_get_serial(dev);
 326
 327         /* Set I2C speed */
 328         ret = diolan_set_speed(dev, speed);
 329         if (ret < 0)
 330                 return ret;
 331
 332         /* Configure I2C clock synchronization */
 333         ret = diolan_set_clock_synch(dev, speed != U2C_I2C_SPEED_FAST);
 334         if (ret < 0)
 335                 return ret;
 336
 337         if (speed != U2C_I2C_SPEED_FAST)
 338                 ret = diolan_set_clock_synch_timeout(dev, DIOLAN_SYNC_TIMEOUT);
 339
 340         return ret;
 341 }
 342
 343 /* i2c layer */
 344
 345 static int diolan_usb_xfer(struct i2c_adapter *adapter, struct i2c_msg *msgs,
 346                            int num)
 347 {
 348         struct i2c_diolan_u2c *dev = i2c_get_adapdata(adapter);
 349         struct i2c_msg *pmsg;
 350         int i, j;
 351         int ret, sret;
 352
 353         ret = diolan_i2c_start(dev);
 354         if (ret < 0)
 355                 return ret;
 356
 357         for (i = 0; i < num; i++) {
 358                 pmsg = &msgs[i];
 359                 if (i) {
 360                         ret = diolan_i2c_repeated_start(dev);
 361                         if (ret < 0)
 362                                 goto abort;
 363                 }
 364                 if (pmsg->flags & I2C_M_RD) {
 365                         ret =
 366                             diolan_i2c_put_byte_ack(dev, (pmsg->addr << 1) | 1);
 367                         if (ret < 0)
 368                                 goto abort;
 369                         for (j = 0; j < pmsg->len; j++) {
 370                                 u8 byte;
 371                                 bool ack = j < pmsg->len - 1;
 372
 373                                 /*
 374                                  * Don't send NACK if this is the first byte
 375                                  * of a SMBUS_BLOCK message.
 376                                  */
 377                                 if (j == 0 && (pmsg->flags & I2C_M_RECV_LEN))
 378                                         ack = true;
 379
 380                                 ret = diolan_i2c_get_byte_ack(dev, ack, &byte);
 381                                 if (ret < 0)
 382                                         goto abort;
 383                                 /*
 384                                  * Adjust count if first received byte is length
 385                                  */
 386                                 if (j == 0 && (pmsg->flags & I2C_M_RECV_LEN)) {
 387                                         if (byte == 0
 388                                             || byte > I2C_SMBUS_BLOCK_MAX) {
 389                                                 ret = -EPROTO;
 390                                                 goto abort;
 391                                         }
 392                                         pmsg->len += byte;
 393                                 }
 394                                 pmsg->buf[j] = byte;
 395                         }
 396                 } else {
 397                         ret = diolan_i2c_put_byte_ack(dev, pmsg->addr << 1);
 398                         if (ret < 0)
 399                                 goto abort;
 400                         for (j = 0; j < pmsg->len; j++) {
 401                                 ret = diolan_i2c_put_byte_ack(dev,
 402                                                               pmsg->buf[j]);
 403                                 if (ret < 0)
 404                                         goto abort;
 405                         }
 406                 }
 407         }
 408 abort:
 409         sret = diolan_i2c_stop(dev);
 410         if (sret < 0 && ret >= 0)
 411                 ret = sret;
 412         return ret;
 413 }
 414
 415 /*
 416  * Return list of supported functionality.
 417  */
 418 static u32 diolan_usb_func(struct i2c_adapter *a)
 419 {
 420         return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL |
 421                I2C_FUNC_SMBUS_READ_BLOCK_DATA | I2C_FUNC_SMBUS_BLOCK_PROC_CALL;
 422 }
 423
 424 static const struct i2c_algorithm diolan_usb_algorithm = {
 425         .master_xfer = diolan_usb_xfer,
 426         .functionality = diolan_usb_func,
 427 };
 428
 429 /* device layer */
 430
 431 static const struct usb_device_id diolan_u2c_table[] = {
 432         { USB_DEVICE(USB_VENDOR_ID_DIOLAN, USB_DEVICE_ID_DIOLAN_U2C) },
 433         { }
 434 };
 435
 436 MODULE_DEVICE_TABLE(usb, diolan_u2c_table);
 437
 438 static void diolan_u2c_free(struct i2c_diolan_u2c *dev)
 439 {
 440         usb_put_dev(dev->usb_dev);
 441         kfree(dev);
 442 }
 443
 444 static int diolan_u2c_probe(struct usb_interface *interface,
 445                             const struct usb_device_id *id)
 446 {
 447         struct i2c_diolan_u2c *dev;
 448         int ret;
 449
 450         /* allocate memory for our device state and initialize it */
 451         dev = kzalloc(sizeof(*dev), GFP_KERNEL);
 452         if (dev == NULL) {
 453                 dev_err(&interface->dev, "no memory for device state\n");
 454                 ret = -ENOMEM;
 455                 goto error;
 456         }
 457
 458         dev->usb_dev = usb_get_dev(interface_to_usbdev(interface));
 459         dev->interface = interface;
 460
 461         /* save our data pointer in this interface device */
 462         usb_set_intfdata(interface, dev);
 463
 464         /* setup i2c adapter description */
 465         dev->adapter.owner = THIS_MODULE;
 466         dev->adapter.class = I2C_CLASS_HWMON;
 467         dev->adapter.algo = &diolan_usb_algorithm;
 468         i2c_set_adapdata(&dev->adapter, dev);
 469         snprintf(dev->adapter.name, sizeof(dev->adapter.name),
 470                  DRIVER_NAME " at bus %03d device %03d",
 471                  dev->usb_dev->bus->busnum, dev->usb_dev->devnum);
 472
 473         dev->adapter.dev.parent = &dev->interface->dev;
 474
 475         /* initialize diolan i2c interface */
 476         ret = diolan_init(dev);
 477         if (ret < 0) {
 478                 dev_err(&interface->dev, "failed to initialize adapter\n");
 479                 goto error_free;
 480         }
 481
 482         /* and finally attach to i2c layer */
 483         ret = i2c_add_adapter(&dev->adapter);
 484         if (ret < 0) {
 485                 dev_err(&interface->dev, "failed to add I2C adapter\n");
 486                 goto error_free;
 487         }
 488
 489         dev_dbg(&interface->dev, "connected " DRIVER_NAME "\n");
 490
 491         return 0;
 492
 493 error_free:
 494         usb_set_intfdata(interface, NULL);
 495         diolan_u2c_free(dev);
 496 error:
 497         return ret;
 498 }
 499
 500 static void diolan_u2c_disconnect(struct usb_interface *interface)
 501 {
 502         struct i2c_diolan_u2c *dev = usb_get_intfdata(interface);
 503
 504         i2c_del_adapter(&dev->adapter);
 505         usb_set_intfdata(interface, NULL);
 506         diolan_u2c_free(dev);
 507
 508         dev_dbg(&interface->dev, "disconnected\n");
 509 }
 510
 511 static struct usb_driver diolan_u2c_driver = {
 512         .name = DRIVER_NAME,
 513         .probe = diolan_u2c_probe,
 514         .disconnect = diolan_u2c_disconnect,
 515         .id_table = diolan_u2c_table,
 516 };
 517
 518 static int __init diolan_u2c_init(void)
 519 {
 520         /* register this driver with the USB subsystem */
 521         return usb_register(&diolan_u2c_driver);
 522 }
 523
 524 static void __exit diolan_u2c_exit(void)
 525 {
 526         /* deregister this driver with the USB subsystem */
 527         usb_deregister(&diolan_u2c_driver);
 528 }
 529
 530 module_init(diolan_u2c_init);
 531 module_exit(diolan_u2c_exit);
 532
 533 MODULE_AUTHOR("Guenter Roeck <guenter.roeck@ericsson.com>");
 534 MODULE_DESCRIPTION(DRIVER_NAME " driver");
 535 MODULE_LICENSE("GPL");