LXR linux/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 */
  84struct 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
  94static uint frequency = U2C_I2C_FREQ_STD;       /* I2C clock frequency in Hz */
  95
  96module_param(frequency, uint, S_IRUGO | S_IWUSR);
  97MODULE_PARM_DESC(frequency, "I2C clock frequency in hertz");
  98
  99/* usb layer */
 100
 101/* Send command to device, and get response. */
 102static 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
 162static 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) */
 170static 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 */
 178static 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 */
 188static 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 */
 204static 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
 223static int diolan_i2c_start(struct i2c_diolan_u2c *dev)
 224{
 225        return diolan_usb_cmd(dev, CMD_I2C_START, false);
 226}
 227
 228static int diolan_i2c_repeated_start(struct i2c_diolan_u2c *dev)
 229{
 230        return diolan_usb_cmd(dev, CMD_I2C_REPEATED_START, false);
 231}
 232
 233static int diolan_i2c_stop(struct i2c_diolan_u2c *dev)
 234{
 235        return diolan_usb_cmd(dev, CMD_I2C_STOP, true);
 236}
 237
 238static 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
 252static 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
 257static 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) */
 263static 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 */
 269static 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
 277static 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
 289static 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
 302static 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
 345static 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        }
 408abort:
 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 */
 418static 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
 424static const struct i2c_algorithm diolan_usb_algorithm = {
 425        .master_xfer = diolan_usb_xfer,
 426        .functionality = diolan_usb_func,
 427};
 428
 429/* device layer */
 430
 431static const struct usb_device_id diolan_u2c_table[] = {
 432        { USB_DEVICE(USB_VENDOR_ID_DIOLAN, USB_DEVICE_ID_DIOLAN_U2C) },
 433        { }
 434};
 435
 436MODULE_DEVICE_TABLE(usb, diolan_u2c_table);
 437
 438static void diolan_u2c_free(struct i2c_diolan_u2c *dev)
 439{
 440        usb_put_dev(dev->usb_dev);
 441        kfree(dev);
 442}
 443
 444static 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
 493error_free:
 494        usb_set_intfdata(interface, NULL);
 495        diolan_u2c_free(dev);
 496error:
 497        return ret;
 498}
 499
 500static 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
 511static 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
 518static int __init diolan_u2c_init(void)
 519{
 520        /* register this driver with the USB subsystem */
 521        return usb_register(&diolan_u2c_driver);
 522}
 523
 524static void __exit diolan_u2c_exit(void)
 525{
 526        /* deregister this driver with the USB subsystem */
 527        usb_deregister(&diolan_u2c_driver);
 528}
 529
 530module_init(diolan_u2c_init);
 531module_exit(diolan_u2c_exit);
 532
 533MODULE_AUTHOR("Guenter Roeck <guenter.roeck@ericsson.com>");
 534MODULE_DESCRIPTION(DRIVER_NAME " driver");
 535MODULE_LICENSE("GPL");
 536