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
  29 /* commands via USB, must match command ids in the firmware */
  30 #define CMD_I2C_READ            0x01
  31 #define CMD_I2C_WRITE           0x02
  32 #define CMD_I2C_SCAN            0x03    /* Returns list of detected devices */
  33 #define CMD_I2C_RELEASE_SDA     0x04
  34 #define CMD_I2C_RELEASE_SCL     0x05
  35 #define CMD_I2C_DROP_SDA        0x06
  36 #define CMD_I2C_DROP_SCL        0x07
  37 #define CMD_I2C_READ_SDA        0x08
  38 #define CMD_I2C_READ_SCL        0x09
  39 #define CMD_GET_FW_VERSION      0x0a
  40 #define CMD_GET_SERIAL          0x0b
  41 #define CMD_I2C_START           0x0c
  42 #define CMD_I2C_STOP            0x0d
  43 #define CMD_I2C_REPEATED_START  0x0e
  44 #define CMD_I2C_PUT_BYTE        0x0f
  45 #define CMD_I2C_GET_BYTE        0x10
  46 #define CMD_I2C_PUT_ACK         0x11
  47 #define CMD_I2C_GET_ACK         0x12
  48 #define CMD_I2C_PUT_BYTE_ACK    0x13
  49 #define CMD_I2C_GET_BYTE_ACK    0x14
  50 #define CMD_I2C_SET_SPEED       0x1b
  51 #define CMD_I2C_GET_SPEED       0x1c
  52 #define CMD_I2C_SET_CLK_SYNC    0x24
  53 #define CMD_I2C_GET_CLK_SYNC    0x25
  54 #define CMD_I2C_SET_CLK_SYNC_TO 0x26
  55 #define CMD_I2C_GET_CLK_SYNC_TO 0x27
  56
  57 #define RESP_OK                 0x00
  58 #define RESP_FAILED             0x01
  59 #define RESP_BAD_MEMADDR        0x04
  60 #define RESP_DATA_ERR           0x05
  61 #define RESP_NOT_IMPLEMENTED    0x06
  62 #define RESP_NACK               0x07
  63 #define RESP_TIMEOUT            0x09
  64
  65 #define U2C_I2C_SPEED_FAST      0       /* 400 kHz */
  66 #define U2C_I2C_SPEED_STD       1       /* 100 kHz */
  67 #define U2C_I2C_SPEED_2KHZ      242     /* 2 kHz, minimum speed */
  68 #define U2C_I2C_SPEED(f)        ((DIV_ROUND_UP(1000000, (f)) - 10) / 2 + 1)
  69
  70 #define U2C_I2C_FREQ_FAST       400000
  71 #define U2C_I2C_FREQ_STD        100000
  72 #define U2C_I2C_FREQ(s)         (1000000 / (2 * (s - 1) + 10))
  73
  74 #define DIOLAN_USB_TIMEOUT      100     /* in ms */
  75 #define DIOLAN_SYNC_TIMEOUT     20      /* in ms */
  76
  77 #define DIOLAN_OUTBUF_LEN       128
  78 #define DIOLAN_FLUSH_LEN        (DIOLAN_OUTBUF_LEN - 4)
  79 #define DIOLAN_INBUF_LEN        256     /* Maximum supported receive length */
  80
  81 /* Structure to hold all of our device specific stuff */
  82 struct i2c_diolan_u2c {
  83         u8 obuffer[DIOLAN_OUTBUF_LEN];  /* output buffer */
  84         u8 ibuffer[DIOLAN_INBUF_LEN];   /* input buffer */
  85         int ep_in, ep_out;              /* Endpoints    */
  86         struct usb_device *usb_dev;     /* the usb device for this device */
  87         struct usb_interface *interface;/* the interface for this device */
  88         struct i2c_adapter adapter;     /* i2c related things */
  89         int olen;                       /* Output buffer length */
  90         int ocount;                     /* Number of enqueued messages */
  91 };
  92
  93 static uint frequency = U2C_I2C_FREQ_STD;       /* I2C clock frequency in Hz */
  94
  95 module_param(frequency, uint, S_IRUGO | S_IWUSR);
  96 MODULE_PARM_DESC(frequency, "I2C clock frequency in hertz");
  97
  98 /* usb layer */
  99
 100 /* Send command to device, and get response. */
 101 static int diolan_usb_transfer(struct i2c_diolan_u2c *dev)
 102 {
 103         int ret = 0;
 104         int actual;
 105         int i;
 106
 107         if (!dev->olen || !dev->ocount)
 108                 return -EINVAL;
 109
 110         ret = usb_bulk_msg(dev->usb_dev,
 111                            usb_sndbulkpipe(dev->usb_dev, dev->ep_out),
 112                            dev->obuffer, dev->olen, &actual,
 113                            DIOLAN_USB_TIMEOUT);
 114         if (!ret) {
 115                 for (i = 0; i < dev->ocount; i++) {
 116                         int tmpret;
 117
 118                         tmpret = usb_bulk_msg(dev->usb_dev,
 119                                               usb_rcvbulkpipe(dev->usb_dev,
 120                                                               dev->ep_in),
 121                                               dev->ibuffer,
 122                                               sizeof(dev->ibuffer), &actual,
 123                                               DIOLAN_USB_TIMEOUT);
 124                         /*
 125                          * Stop command processing if a previous command
 126                          * returned an error.
 127                          * Note that we still need to retrieve all messages.
 128                          */
 129                         if (ret < 0)
 130                                 continue;
 131                         ret = tmpret;
 132                         if (ret == 0 && actual > 0) {
 133                                 switch (dev->ibuffer[actual - 1]) {
 134                                 case RESP_NACK:
 135                                         /*
 136                                          * Return ENXIO if NACK was received as
 137                                          * response to the address phase,
 138                                          * EIO otherwise
 139                                          */
 140                                         ret = i == 1 ? -ENXIO : -EIO;
 141                                         break;
 142                                 case RESP_TIMEOUT:
 143                                         ret = -ETIMEDOUT;
 144                                         break;
 145                                 case RESP_OK:
 146                                         /* strip off return code */
 147                                         ret = actual - 1;
 148                                         break;
 149                                 default:
 150                                         ret = -EIO;
 151                                         break;
 152                                 }
 153                         }
 154                 }
 155         }
 156         dev->olen = 0;
 157         dev->ocount = 0;
 158         return ret;
 159 }
 160
 161 static int diolan_write_cmd(struct i2c_diolan_u2c *dev, bool flush)
 162 {
 163         if (flush || dev->olen >= DIOLAN_FLUSH_LEN)
 164                 return diolan_usb_transfer(dev);
 165         return 0;
 166 }
 167
 168 /* Send command (no data) */
 169 static int diolan_usb_cmd(struct i2c_diolan_u2c *dev, u8 command, bool flush)
 170 {
 171         dev->obuffer[dev->olen++] = command;
 172         dev->ocount++;
 173         return diolan_write_cmd(dev, flush);
 174 }
 175
 176 /* Send command with one byte of data */
 177 static int diolan_usb_cmd_data(struct i2c_diolan_u2c *dev, u8 command, u8 data,
 178                                bool flush)
 179 {
 180         dev->obuffer[dev->olen++] = command;
 181         dev->obuffer[dev->olen++] = data;
 182         dev->ocount++;
 183         return diolan_write_cmd(dev, flush);
 184 }
 185
 186 /* Send command with two bytes of data */
 187 static int diolan_usb_cmd_data2(struct i2c_diolan_u2c *dev, u8 command, u8 d1,
 188                                 u8 d2, bool flush)
 189 {
 190         dev->obuffer[dev->olen++] = command;
 191         dev->obuffer[dev->olen++] = d1;
 192         dev->obuffer[dev->olen++] = d2;
 193         dev->ocount++;
 194         return diolan_write_cmd(dev, flush);
 195 }
 196
 197 /*
 198  * Flush input queue.
 199  * If we don't do this at startup and the controller has queued up
 200  * messages which were not retrieved, it will stop responding
 201  * at some point.
 202  */
 203 static void diolan_flush_input(struct i2c_diolan_u2c *dev)
 204 {
 205         int i;
 206
 207         for (i = 0; i < 10; i++) {
 208                 int actual = 0;
 209                 int ret;
 210
 211                 ret = usb_bulk_msg(dev->usb_dev,
 212                                    usb_rcvbulkpipe(dev->usb_dev, dev->ep_in),
 213                                    dev->ibuffer, sizeof(dev->ibuffer), &actual,
 214                                    DIOLAN_USB_TIMEOUT);
 215                 if (ret < 0 || actual == 0)
 216                         break;
 217         }
 218         if (i == 10)
 219                 dev_err(&dev->interface->dev, "Failed to flush input buffer\n");
 220 }
 221
 222 static int diolan_i2c_start(struct i2c_diolan_u2c *dev)
 223 {
 224         return diolan_usb_cmd(dev, CMD_I2C_START, false);
 225 }
 226
 227 static int diolan_i2c_repeated_start(struct i2c_diolan_u2c *dev)
 228 {
 229         return diolan_usb_cmd(dev, CMD_I2C_REPEATED_START, false);
 230 }
 231
 232 static int diolan_i2c_stop(struct i2c_diolan_u2c *dev)
 233 {
 234         return diolan_usb_cmd(dev, CMD_I2C_STOP, true);
 235 }
 236
 237 static int diolan_i2c_get_byte_ack(struct i2c_diolan_u2c *dev, bool ack,
 238                                    u8 *byte)
 239 {
 240         int ret;
 241
 242         ret = diolan_usb_cmd_data(dev, CMD_I2C_GET_BYTE_ACK, ack, true);
 243         if (ret > 0)
 244                 *byte = dev->ibuffer[0];
 245         else if (ret == 0)
 246                 ret = -EIO;
 247
 248         return ret;
 249 }
 250
 251 static int diolan_i2c_put_byte_ack(struct i2c_diolan_u2c *dev, u8 byte)
 252 {
 253         return diolan_usb_cmd_data(dev, CMD_I2C_PUT_BYTE_ACK, byte, false);
 254 }
 255
 256 static int diolan_set_speed(struct i2c_diolan_u2c *dev, u8 speed)
 257 {
 258         return diolan_usb_cmd_data(dev, CMD_I2C_SET_SPEED, speed, true);
 259 }
 260
 261 /* Enable or disable clock synchronization (stretching) */
 262 static int diolan_set_clock_synch(struct i2c_diolan_u2c *dev, bool enable)
 263 {
 264         return diolan_usb_cmd_data(dev, CMD_I2C_SET_CLK_SYNC, enable, true);
 265 }
 266
 267 /* Set clock synchronization timeout in ms */
 268 static int diolan_set_clock_synch_timeout(struct i2c_diolan_u2c *dev, int ms)
 269 {
 270         int to_val = ms * 10;
 271
 272         return diolan_usb_cmd_data2(dev, CMD_I2C_SET_CLK_SYNC_TO,
 273                                     to_val & 0xff, (to_val >> 8) & 0xff, true);
 274 }
 275
 276 static void diolan_fw_version(struct i2c_diolan_u2c *dev)
 277 {
 278         int ret;
 279
 280         ret = diolan_usb_cmd(dev, CMD_GET_FW_VERSION, true);
 281         if (ret >= 2)
 282                 dev_info(&dev->interface->dev,
 283                          "Diolan U2C firmware version %u.%u\n",
 284                          (unsigned int)dev->ibuffer[0],
 285                          (unsigned int)dev->ibuffer[1]);
 286 }
 287
 288 static void diolan_get_serial(struct i2c_diolan_u2c *dev)
 289 {
 290         int ret;
 291         u32 serial;
 292
 293         ret = diolan_usb_cmd(dev, CMD_GET_SERIAL, true);
 294         if (ret >= 4) {
 295                 serial = le32_to_cpu(*(u32 *)dev->ibuffer);
 296                 dev_info(&dev->interface->dev,
 297                          "Diolan U2C serial number %u\n", serial);
 298         }
 299 }
 300
 301 static int diolan_init(struct i2c_diolan_u2c *dev)
 302 {
 303         int speed, ret;
 304
 305         if (frequency >= 200000) {
 306                 speed = U2C_I2C_SPEED_FAST;
 307                 frequency = U2C_I2C_FREQ_FAST;
 308         } else if (frequency >= 100000 || frequency == 0) {
 309                 speed = U2C_I2C_SPEED_STD;
 310                 frequency = U2C_I2C_FREQ_STD;
 311         } else {
 312                 speed = U2C_I2C_SPEED(frequency);
 313                 if (speed > U2C_I2C_SPEED_2KHZ)
 314                         speed = U2C_I2C_SPEED_2KHZ;
 315                 frequency = U2C_I2C_FREQ(speed);
 316         }
 317
 318         dev_info(&dev->interface->dev,
 319                  "Diolan U2C at USB bus %03d address %03d speed %d Hz\n",
 320                  dev->usb_dev->bus->busnum, dev->usb_dev->devnum, frequency);
 321
 322         diolan_flush_input(dev);
 323         diolan_fw_version(dev);
 324         diolan_get_serial(dev);
 325
 326         /* Set I2C speed */
 327         ret = diolan_set_speed(dev, speed);
 328         if (ret < 0)
 329                 return ret;
 330
 331         /* Configure I2C clock synchronization */
 332         ret = diolan_set_clock_synch(dev, speed != U2C_I2C_SPEED_FAST);
 333         if (ret < 0)
 334                 return ret;
 335
 336         if (speed != U2C_I2C_SPEED_FAST)
 337                 ret = diolan_set_clock_synch_timeout(dev, DIOLAN_SYNC_TIMEOUT);
 338
 339         return ret;
 340 }
 341
 342 /* i2c layer */
 343
 344 static int diolan_usb_xfer(struct i2c_adapter *adapter, struct i2c_msg *msgs,
 345                            int num)
 346 {
 347         struct i2c_diolan_u2c *dev = i2c_get_adapdata(adapter);
 348         struct i2c_msg *pmsg;
 349         int i, j;
 350         int ret, sret;
 351
 352         ret = diolan_i2c_start(dev);
 353         if (ret < 0)
 354                 return ret;
 355
 356         for (i = 0; i < num; i++) {
 357                 pmsg = &msgs[i];
 358                 if (i) {
 359                         ret = diolan_i2c_repeated_start(dev);
 360                         if (ret < 0)
 361                                 goto abort;
 362                 }
 363                 ret = diolan_i2c_put_byte_ack(dev,
 364                                               i2c_8bit_addr_from_msg(pmsg));
 365                 if (ret < 0)
 366                         goto abort;
 367                 if (pmsg->flags & I2C_M_RD) {
 368                         for (j = 0; j < pmsg->len; j++) {
 369                                 u8 byte;
 370                                 bool ack = j < pmsg->len - 1;
 371
 372                                 /*
 373                                  * Don't send NACK if this is the first byte
 374                                  * of a SMBUS_BLOCK message.
 375                                  */
 376                                 if (j == 0 && (pmsg->flags & I2C_M_RECV_LEN))
 377                                         ack = true;
 378
 379                                 ret = diolan_i2c_get_byte_ack(dev, ack, &byte);
 380                                 if (ret < 0)
 381                                         goto abort;
 382                                 /*
 383                                  * Adjust count if first received byte is length
 384                                  */
 385                                 if (j == 0 && (pmsg->flags & I2C_M_RECV_LEN)) {
 386                                         if (byte == 0
 387                                             || byte > I2C_SMBUS_BLOCK_MAX) {
 388                                                 ret = -EPROTO;
 389                                                 goto abort;
 390                                         }
 391                                         pmsg->len += byte;
 392                                 }
 393                                 pmsg->buf[j] = byte;
 394                         }
 395                 } else {
 396                         for (j = 0; j < pmsg->len; j++) {
 397                                 ret = diolan_i2c_put_byte_ack(dev,
 398                                                               pmsg->buf[j]);
 399                                 if (ret < 0)
 400                                         goto abort;
 401                         }
 402                 }
 403         }
 404         ret = num;
 405 abort:
 406         sret = diolan_i2c_stop(dev);
 407         if (sret < 0 && ret >= 0)
 408                 ret = sret;
 409         return ret;
 410 }
 411
 412 /*
 413  * Return list of supported functionality.
 414  */
 415 static u32 diolan_usb_func(struct i2c_adapter *a)
 416 {
 417         return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL |
 418                I2C_FUNC_SMBUS_READ_BLOCK_DATA | I2C_FUNC_SMBUS_BLOCK_PROC_CALL;
 419 }
 420
 421 static const struct i2c_algorithm diolan_usb_algorithm = {
 422         .master_xfer = diolan_usb_xfer,
 423         .functionality = diolan_usb_func,
 424 };
 425
 426 /* device layer */
 427
 428 static const struct usb_device_id diolan_u2c_table[] = {
 429         { USB_DEVICE(USB_VENDOR_ID_DIOLAN, USB_DEVICE_ID_DIOLAN_U2C) },
 430         { }
 431 };
 432
 433 MODULE_DEVICE_TABLE(usb, diolan_u2c_table);
 434
 435 static void diolan_u2c_free(struct i2c_diolan_u2c *dev)
 436 {
 437         usb_put_dev(dev->usb_dev);
 438         kfree(dev);
 439 }
 440
 441 static int diolan_u2c_probe(struct usb_interface *interface,
 442                             const struct usb_device_id *id)
 443 {
 444         struct usb_host_interface *hostif = interface->cur_altsetting;
 445         struct i2c_diolan_u2c *dev;
 446         int ret;
 447
 448         if (hostif->desc.bInterfaceNumber != 0
 449             || hostif->desc.bNumEndpoints < 2)
 450                 return -ENODEV;
 451
 452         /* allocate memory for our device state and initialize it */
 453         dev = kzalloc(sizeof(*dev), GFP_KERNEL);
 454         if (dev == NULL) {
 455                 ret = -ENOMEM;
 456                 goto error;
 457         }
 458         dev->ep_out = hostif->endpoint[0].desc.bEndpointAddress;
 459         dev->ep_in = hostif->endpoint[1].desc.bEndpointAddress;
 460
 461         dev->usb_dev = usb_get_dev(interface_to_usbdev(interface));
 462         dev->interface = interface;
 463
 464         /* save our data pointer in this interface device */
 465         usb_set_intfdata(interface, dev);
 466
 467         /* setup i2c adapter description */
 468         dev->adapter.owner = THIS_MODULE;
 469         dev->adapter.class = I2C_CLASS_HWMON;
 470         dev->adapter.algo = &diolan_usb_algorithm;
 471         i2c_set_adapdata(&dev->adapter, dev);
 472         snprintf(dev->adapter.name, sizeof(dev->adapter.name),
 473                  DRIVER_NAME " at bus %03d device %03d",
 474                  dev->usb_dev->bus->busnum, dev->usb_dev->devnum);
 475
 476         dev->adapter.dev.parent = &dev->interface->dev;
 477
 478         /* initialize diolan i2c interface */
 479         ret = diolan_init(dev);
 480         if (ret < 0) {
 481                 dev_err(&interface->dev, "failed to initialize adapter\n");
 482                 goto error_free;
 483         }
 484
 485         /* and finally attach to i2c layer */
 486         ret = i2c_add_adapter(&dev->adapter);
 487         if (ret < 0)
 488                 goto error_free;
 489
 490         dev_dbg(&interface->dev, "connected " DRIVER_NAME "\n");
 491
 492         return 0;
 493
 494 error_free:
 495         usb_set_intfdata(interface, NULL);
 496         diolan_u2c_free(dev);
 497 error:
 498         return ret;
 499 }
 500
 501 static void diolan_u2c_disconnect(struct usb_interface *interface)
 502 {
 503         struct i2c_diolan_u2c *dev = usb_get_intfdata(interface);
 504
 505         i2c_del_adapter(&dev->adapter);
 506         usb_set_intfdata(interface, NULL);
 507         diolan_u2c_free(dev);
 508
 509         dev_dbg(&interface->dev, "disconnected\n");
 510 }
 511
 512 static struct usb_driver diolan_u2c_driver = {
 513         .name = DRIVER_NAME,
 514         .probe = diolan_u2c_probe,
 515         .disconnect = diolan_u2c_disconnect,
 516         .id_table = diolan_u2c_table,
 517 };
 518
 519 module_usb_driver(diolan_u2c_driver);
 520
 521 MODULE_AUTHOR("Guenter Roeck <linux@roeck-us.net>");
 522 MODULE_DESCRIPTION(DRIVER_NAME " driver");
 523 MODULE_LICENSE("GPL");