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
  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 */
  82struct 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
  93static uint frequency = U2C_I2C_FREQ_STD;       /* I2C clock frequency in Hz */
  94
  95module_param(frequency, uint, S_IRUGO | S_IWUSR);
  96MODULE_PARM_DESC(frequency, "I2C clock frequency in hertz");
  97
  98/* usb layer */
  99
 100/* Send command to device, and get response. */
 101static 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
 161static 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) */
 169static 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 */
 177static 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 */
 187static 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 */
 203static 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
 222static int diolan_i2c_start(struct i2c_diolan_u2c *dev)
 223{
 224        return diolan_usb_cmd(dev, CMD_I2C_START, false);
 225}
 226
 227static int diolan_i2c_repeated_start(struct i2c_diolan_u2c *dev)
 228{
 229        return diolan_usb_cmd(dev, CMD_I2C_REPEATED_START, false);
 230}
 231
 232static int diolan_i2c_stop(struct i2c_diolan_u2c *dev)
 233{
 234        return diolan_usb_cmd(dev, CMD_I2C_STOP, true);
 235}
 236
 237static 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
 251static 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
 256static 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) */
 262static 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 */
 268static 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
 276static 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
 288static 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
 301static 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
 344static 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                if (pmsg->flags & I2C_M_RD) {
 364                        ret =
 365                            diolan_i2c_put_byte_ack(dev, (pmsg->addr << 1) | 1);
 366                        if (ret < 0)
 367                                goto abort;
 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                        ret = diolan_i2c_put_byte_ack(dev, pmsg->addr << 1);
 397                        if (ret < 0)
 398                                goto abort;
 399                        for (j = 0; j < pmsg->len; j++) {
 400                                ret = diolan_i2c_put_byte_ack(dev,
 401                                                              pmsg->buf[j]);
 402                                if (ret < 0)
 403                                        goto abort;
 404                        }
 405                }
 406        }
 407        ret = num;
 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 usb_host_interface *hostif = interface->cur_altsetting;
 448        struct i2c_diolan_u2c *dev;
 449        int ret;
 450
 451        if (hostif->desc.bInterfaceNumber != 0
 452            || hostif->desc.bNumEndpoints < 2)
 453                return -ENODEV;
 454
 455        /* allocate memory for our device state and initialize it */
 456        dev = kzalloc(sizeof(*dev), GFP_KERNEL);
 457        if (dev == NULL) {
 458                ret = -ENOMEM;
 459                goto error;
 460        }
 461        dev->ep_out = hostif->endpoint[0].desc.bEndpointAddress;
 462        dev->ep_in = hostif->endpoint[1].desc.bEndpointAddress;
 463
 464        dev->usb_dev = usb_get_dev(interface_to_usbdev(interface));
 465        dev->interface = interface;
 466
 467        /* save our data pointer in this interface device */
 468        usb_set_intfdata(interface, dev);
 469
 470        /* setup i2c adapter description */
 471        dev->adapter.owner = THIS_MODULE;
 472        dev->adapter.class = I2C_CLASS_HWMON;
 473        dev->adapter.algo = &diolan_usb_algorithm;
 474        i2c_set_adapdata(&dev->adapter, dev);
 475        snprintf(dev->adapter.name, sizeof(dev->adapter.name),
 476                 DRIVER_NAME " at bus %03d device %03d",
 477                 dev->usb_dev->bus->busnum, dev->usb_dev->devnum);
 478
 479        dev->adapter.dev.parent = &dev->interface->dev;
 480
 481        /* initialize diolan i2c interface */
 482        ret = diolan_init(dev);
 483        if (ret < 0) {
 484                dev_err(&interface->dev, "failed to initialize adapter\n");
 485                goto error_free;
 486        }
 487
 488        /* and finally attach to i2c layer */
 489        ret = i2c_add_adapter(&dev->adapter);
 490        if (ret < 0) {
 491                dev_err(&interface->dev, "failed to add I2C adapter\n");
 492                goto error_free;
 493        }
 494
 495        dev_dbg(&interface->dev, "connected " DRIVER_NAME "\n");
 496
 497        return 0;
 498
 499error_free:
 500        usb_set_intfdata(interface, NULL);
 501        diolan_u2c_free(dev);
 502error:
 503        return ret;
 504}
 505
 506static void diolan_u2c_disconnect(struct usb_interface *interface)
 507{
 508        struct i2c_diolan_u2c *dev = usb_get_intfdata(interface);
 509
 510        i2c_del_adapter(&dev->adapter);
 511        usb_set_intfdata(interface, NULL);
 512        diolan_u2c_free(dev);
 513
 514        dev_dbg(&interface->dev, "disconnected\n");
 515}
 516
 517static struct usb_driver diolan_u2c_driver = {
 518        .name = DRIVER_NAME,
 519        .probe = diolan_u2c_probe,
 520        .disconnect = diolan_u2c_disconnect,
 521        .id_table = diolan_u2c_table,
 522};
 523
 524module_usb_driver(diolan_u2c_driver);
 525
 526MODULE_AUTHOR("Guenter Roeck <linux@roeck-us.net>");
 527MODULE_DESCRIPTION(DRIVER_NAME " driver");
 528MODULE_LICENSE("GPL");
 529