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

   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * Driver for the Diolan u2c-12 USB-I2C adapter
   4 *
   5 * Copyright (c) 2010-2011 Ericsson AB
   6 *
   7 * Derived from:
   8 *  i2c-tiny-usb.c
   9 *  Copyright (C) 2006-2007 Till Harbaum (Till@Harbaum.org)
  10 */
  11
  12#include <linux/kernel.h>
  13#include <linux/errno.h>
  14#include <linux/module.h>
  15#include <linux/types.h>
  16#include <linux/slab.h>
  17#include <linux/usb.h>
  18#include <linux/i2c.h>
  19
  20#define DRIVER_NAME             "i2c-diolan-u2c"
  21
  22#define USB_VENDOR_ID_DIOLAN            0x0abf
  23#define USB_DEVICE_ID_DIOLAN_U2C        0x3370
  24
  25
  26/* commands via USB, must match command ids in the firmware */
  27#define CMD_I2C_READ            0x01
  28#define CMD_I2C_WRITE           0x02
  29#define CMD_I2C_SCAN            0x03    /* Returns list of detected devices */
  30#define CMD_I2C_RELEASE_SDA     0x04
  31#define CMD_I2C_RELEASE_SCL     0x05
  32#define CMD_I2C_DROP_SDA        0x06
  33#define CMD_I2C_DROP_SCL        0x07
  34#define CMD_I2C_READ_SDA        0x08
  35#define CMD_I2C_READ_SCL        0x09
  36#define CMD_GET_FW_VERSION      0x0a
  37#define CMD_GET_SERIAL          0x0b
  38#define CMD_I2C_START           0x0c
  39#define CMD_I2C_STOP            0x0d
  40#define CMD_I2C_REPEATED_START  0x0e
  41#define CMD_I2C_PUT_BYTE        0x0f
  42#define CMD_I2C_GET_BYTE        0x10
  43#define CMD_I2C_PUT_ACK         0x11
  44#define CMD_I2C_GET_ACK         0x12
  45#define CMD_I2C_PUT_BYTE_ACK    0x13
  46#define CMD_I2C_GET_BYTE_ACK    0x14
  47#define CMD_I2C_SET_SPEED       0x1b
  48#define CMD_I2C_GET_SPEED       0x1c
  49#define CMD_I2C_SET_CLK_SYNC    0x24
  50#define CMD_I2C_GET_CLK_SYNC    0x25
  51#define CMD_I2C_SET_CLK_SYNC_TO 0x26
  52#define CMD_I2C_GET_CLK_SYNC_TO 0x27
  53
  54#define RESP_OK                 0x00
  55#define RESP_FAILED             0x01
  56#define RESP_BAD_MEMADDR        0x04
  57#define RESP_DATA_ERR           0x05
  58#define RESP_NOT_IMPLEMENTED    0x06
  59#define RESP_NACK               0x07
  60#define RESP_TIMEOUT            0x09
  61
  62#define U2C_I2C_SPEED_FAST      0       /* 400 kHz */
  63#define U2C_I2C_SPEED_STD       1       /* 100 kHz */
  64#define U2C_I2C_SPEED_2KHZ      242     /* 2 kHz, minimum speed */
  65#define U2C_I2C_SPEED(f)        ((DIV_ROUND_UP(1000000, (f)) - 10) / 2 + 1)
  66
  67#define U2C_I2C_FREQ_FAST       400000
  68#define U2C_I2C_FREQ_STD        100000
  69#define U2C_I2C_FREQ(s)         (1000000 / (2 * (s - 1) + 10))
  70
  71#define DIOLAN_USB_TIMEOUT      100     /* in ms */
  72#define DIOLAN_SYNC_TIMEOUT     20      /* in ms */
  73
  74#define DIOLAN_OUTBUF_LEN       128
  75#define DIOLAN_FLUSH_LEN        (DIOLAN_OUTBUF_LEN - 4)
  76#define DIOLAN_INBUF_LEN        256     /* Maximum supported receive length */
  77
  78/* Structure to hold all of our device specific stuff */
  79struct i2c_diolan_u2c {
  80        u8 obuffer[DIOLAN_OUTBUF_LEN];  /* output buffer */
  81        u8 ibuffer[DIOLAN_INBUF_LEN];   /* input buffer */
  82        int ep_in, ep_out;              /* Endpoints    */
  83        struct usb_device *usb_dev;     /* the usb device for this device */
  84        struct usb_interface *interface;/* the interface for this device */
  85        struct i2c_adapter adapter;     /* i2c related things */
  86        int olen;                       /* Output buffer length */
  87        int ocount;                     /* Number of enqueued messages */
  88};
  89
  90static uint frequency = U2C_I2C_FREQ_STD;       /* I2C clock frequency in Hz */
  91
  92module_param(frequency, uint, S_IRUGO | S_IWUSR);
  93MODULE_PARM_DESC(frequency, "I2C clock frequency in hertz");
  94
  95/* usb layer */
  96
  97/* Send command to device, and get response. */
  98static int diolan_usb_transfer(struct i2c_diolan_u2c *dev)
  99{
 100        int ret = 0;
 101        int actual;
 102        int i;
 103
 104        if (!dev->olen || !dev->ocount)
 105                return -EINVAL;
 106
 107        ret = usb_bulk_msg(dev->usb_dev,
 108                           usb_sndbulkpipe(dev->usb_dev, dev->ep_out),
 109                           dev->obuffer, dev->olen, &actual,
 110                           DIOLAN_USB_TIMEOUT);
 111        if (!ret) {
 112                for (i = 0; i < dev->ocount; i++) {
 113                        int tmpret;
 114
 115                        tmpret = usb_bulk_msg(dev->usb_dev,
 116                                              usb_rcvbulkpipe(dev->usb_dev,
 117                                                              dev->ep_in),
 118                                              dev->ibuffer,
 119                                              sizeof(dev->ibuffer), &actual,
 120                                              DIOLAN_USB_TIMEOUT);
 121                        /*
 122                         * Stop command processing if a previous command
 123                         * returned an error.
 124                         * Note that we still need to retrieve all messages.
 125                         */
 126                        if (ret < 0)
 127                                continue;
 128                        ret = tmpret;
 129                        if (ret == 0 && actual > 0) {
 130                                switch (dev->ibuffer[actual - 1]) {
 131                                case RESP_NACK:
 132                                        /*
 133                                         * Return ENXIO if NACK was received as
 134                                         * response to the address phase,
 135                                         * EIO otherwise
 136                                         */
 137                                        ret = i == 1 ? -ENXIO : -EIO;
 138                                        break;
 139                                case RESP_TIMEOUT:
 140                                        ret = -ETIMEDOUT;
 141                                        break;
 142                                case RESP_OK:
 143                                        /* strip off return code */
 144                                        ret = actual - 1;
 145                                        break;
 146                                default:
 147                                        ret = -EIO;
 148                                        break;
 149                                }
 150                        }
 151                }
 152        }
 153        dev->olen = 0;
 154        dev->ocount = 0;
 155        return ret;
 156}
 157
 158static int diolan_write_cmd(struct i2c_diolan_u2c *dev, bool flush)
 159{
 160        if (flush || dev->olen >= DIOLAN_FLUSH_LEN)
 161                return diolan_usb_transfer(dev);
 162        return 0;
 163}
 164
 165/* Send command (no data) */
 166static int diolan_usb_cmd(struct i2c_diolan_u2c *dev, u8 command, bool flush)
 167{
 168        dev->obuffer[dev->olen++] = command;
 169        dev->ocount++;
 170        return diolan_write_cmd(dev, flush);
 171}
 172
 173/* Send command with one byte of data */
 174static int diolan_usb_cmd_data(struct i2c_diolan_u2c *dev, u8 command, u8 data,
 175                               bool flush)
 176{
 177        dev->obuffer[dev->olen++] = command;
 178        dev->obuffer[dev->olen++] = data;
 179        dev->ocount++;
 180        return diolan_write_cmd(dev, flush);
 181}
 182
 183/* Send command with two bytes of data */
 184static int diolan_usb_cmd_data2(struct i2c_diolan_u2c *dev, u8 command, u8 d1,
 185                                u8 d2, bool flush)
 186{
 187        dev->obuffer[dev->olen++] = command;
 188        dev->obuffer[dev->olen++] = d1;
 189        dev->obuffer[dev->olen++] = d2;
 190        dev->ocount++;
 191        return diolan_write_cmd(dev, flush);
 192}
 193
 194/*
 195 * Flush input queue.
 196 * If we don't do this at startup and the controller has queued up
 197 * messages which were not retrieved, it will stop responding
 198 * at some point.
 199 */
 200static void diolan_flush_input(struct i2c_diolan_u2c *dev)
 201{
 202        int i;
 203
 204        for (i = 0; i < 10; i++) {
 205                int actual = 0;
 206                int ret;
 207
 208                ret = usb_bulk_msg(dev->usb_dev,
 209                                   usb_rcvbulkpipe(dev->usb_dev, dev->ep_in),
 210                                   dev->ibuffer, sizeof(dev->ibuffer), &actual,
 211                                   DIOLAN_USB_TIMEOUT);
 212                if (ret < 0 || actual == 0)
 213                        break;
 214        }
 215        if (i == 10)
 216                dev_err(&dev->interface->dev, "Failed to flush input buffer\n");
 217}
 218
 219static int diolan_i2c_start(struct i2c_diolan_u2c *dev)
 220{
 221        return diolan_usb_cmd(dev, CMD_I2C_START, false);
 222}
 223
 224static int diolan_i2c_repeated_start(struct i2c_diolan_u2c *dev)
 225{
 226        return diolan_usb_cmd(dev, CMD_I2C_REPEATED_START, false);
 227}
 228
 229static int diolan_i2c_stop(struct i2c_diolan_u2c *dev)
 230{
 231        return diolan_usb_cmd(dev, CMD_I2C_STOP, true);
 232}
 233
 234static int diolan_i2c_get_byte_ack(struct i2c_diolan_u2c *dev, bool ack,
 235                                   u8 *byte)
 236{
 237        int ret;
 238
 239        ret = diolan_usb_cmd_data(dev, CMD_I2C_GET_BYTE_ACK, ack, true);
 240        if (ret > 0)
 241                *byte = dev->ibuffer[0];
 242        else if (ret == 0)
 243                ret = -EIO;
 244
 245        return ret;
 246}
 247
 248static int diolan_i2c_put_byte_ack(struct i2c_diolan_u2c *dev, u8 byte)
 249{
 250        return diolan_usb_cmd_data(dev, CMD_I2C_PUT_BYTE_ACK, byte, false);
 251}
 252
 253static int diolan_set_speed(struct i2c_diolan_u2c *dev, u8 speed)
 254{
 255        return diolan_usb_cmd_data(dev, CMD_I2C_SET_SPEED, speed, true);
 256}
 257
 258/* Enable or disable clock synchronization (stretching) */
 259static int diolan_set_clock_synch(struct i2c_diolan_u2c *dev, bool enable)
 260{
 261        return diolan_usb_cmd_data(dev, CMD_I2C_SET_CLK_SYNC, enable, true);
 262}
 263
 264/* Set clock synchronization timeout in ms */
 265static int diolan_set_clock_synch_timeout(struct i2c_diolan_u2c *dev, int ms)
 266{
 267        int to_val = ms * 10;
 268
 269        return diolan_usb_cmd_data2(dev, CMD_I2C_SET_CLK_SYNC_TO,
 270                                    to_val & 0xff, (to_val >> 8) & 0xff, true);
 271}
 272
 273static void diolan_fw_version(struct i2c_diolan_u2c *dev)
 274{
 275        int ret;
 276
 277        ret = diolan_usb_cmd(dev, CMD_GET_FW_VERSION, true);
 278        if (ret >= 2)
 279                dev_info(&dev->interface->dev,
 280                         "Diolan U2C firmware version %u.%u\n",
 281                         (unsigned int)dev->ibuffer[0],
 282                         (unsigned int)dev->ibuffer[1]);
 283}
 284
 285static void diolan_get_serial(struct i2c_diolan_u2c *dev)
 286{
 287        int ret;
 288        u32 serial;
 289
 290        ret = diolan_usb_cmd(dev, CMD_GET_SERIAL, true);
 291        if (ret >= 4) {
 292                serial = le32_to_cpu(*(u32 *)dev->ibuffer);
 293                dev_info(&dev->interface->dev,
 294                         "Diolan U2C serial number %u\n", serial);
 295        }
 296}
 297
 298static int diolan_init(struct i2c_diolan_u2c *dev)
 299{
 300        int speed, ret;
 301
 302        if (frequency >= 200000) {
 303                speed = U2C_I2C_SPEED_FAST;
 304                frequency = U2C_I2C_FREQ_FAST;
 305        } else if (frequency >= 100000 || frequency == 0) {
 306                speed = U2C_I2C_SPEED_STD;
 307                frequency = U2C_I2C_FREQ_STD;
 308        } else {
 309                speed = U2C_I2C_SPEED(frequency);
 310                if (speed > U2C_I2C_SPEED_2KHZ)
 311                        speed = U2C_I2C_SPEED_2KHZ;
 312                frequency = U2C_I2C_FREQ(speed);
 313        }
 314
 315        dev_info(&dev->interface->dev,
 316                 "Diolan U2C at USB bus %03d address %03d speed %d Hz\n",
 317                 dev->usb_dev->bus->busnum, dev->usb_dev->devnum, frequency);
 318
 319        diolan_flush_input(dev);
 320        diolan_fw_version(dev);
 321        diolan_get_serial(dev);
 322
 323        /* Set I2C speed */
 324        ret = diolan_set_speed(dev, speed);
 325        if (ret < 0)
 326                return ret;
 327
 328        /* Configure I2C clock synchronization */
 329        ret = diolan_set_clock_synch(dev, speed != U2C_I2C_SPEED_FAST);
 330        if (ret < 0)
 331                return ret;
 332
 333        if (speed != U2C_I2C_SPEED_FAST)
 334                ret = diolan_set_clock_synch_timeout(dev, DIOLAN_SYNC_TIMEOUT);
 335
 336        return ret;
 337}
 338
 339/* i2c layer */
 340
 341static int diolan_usb_xfer(struct i2c_adapter *adapter, struct i2c_msg *msgs,
 342                           int num)
 343{
 344        struct i2c_diolan_u2c *dev = i2c_get_adapdata(adapter);
 345        struct i2c_msg *pmsg;
 346        int i, j;
 347        int ret, sret;
 348
 349        ret = diolan_i2c_start(dev);
 350        if (ret < 0)
 351                return ret;
 352
 353        for (i = 0; i < num; i++) {
 354                pmsg = &msgs[i];
 355                if (i) {
 356                        ret = diolan_i2c_repeated_start(dev);
 357                        if (ret < 0)
 358                                goto abort;
 359                }
 360                ret = diolan_i2c_put_byte_ack(dev,
 361                                              i2c_8bit_addr_from_msg(pmsg));
 362                if (ret < 0)
 363                        goto abort;
 364                if (pmsg->flags & I2C_M_RD) {
 365                        for (j = 0; j < pmsg->len; j++) {
 366                                u8 byte;
 367                                bool ack = j < pmsg->len - 1;
 368
 369                                /*
 370                                 * Don't send NACK if this is the first byte
 371                                 * of a SMBUS_BLOCK message.
 372                                 */
 373                                if (j == 0 && (pmsg->flags & I2C_M_RECV_LEN))
 374                                        ack = true;
 375
 376                                ret = diolan_i2c_get_byte_ack(dev, ack, &byte);
 377                                if (ret < 0)
 378                                        goto abort;
 379                                /*
 380                                 * Adjust count if first received byte is length
 381                                 */
 382                                if (j == 0 && (pmsg->flags & I2C_M_RECV_LEN)) {
 383                                        if (byte == 0
 384                                            || byte > I2C_SMBUS_BLOCK_MAX) {
 385                                                ret = -EPROTO;
 386                                                goto abort;
 387                                        }
 388                                        pmsg->len += byte;
 389                                }
 390                                pmsg->buf[j] = byte;
 391                        }
 392                } else {
 393                        for (j = 0; j < pmsg->len; j++) {
 394                                ret = diolan_i2c_put_byte_ack(dev,
 395                                                              pmsg->buf[j]);
 396                                if (ret < 0)
 397                                        goto abort;
 398                        }
 399                }
 400        }
 401        ret = num;
 402abort:
 403        sret = diolan_i2c_stop(dev);
 404        if (sret < 0 && ret >= 0)
 405                ret = sret;
 406        return ret;
 407}
 408
 409/*
 410 * Return list of supported functionality.
 411 */
 412static u32 diolan_usb_func(struct i2c_adapter *a)
 413{
 414        return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL |
 415               I2C_FUNC_SMBUS_READ_BLOCK_DATA | I2C_FUNC_SMBUS_BLOCK_PROC_CALL;
 416}
 417
 418static const struct i2c_algorithm diolan_usb_algorithm = {
 419        .master_xfer = diolan_usb_xfer,
 420        .functionality = diolan_usb_func,
 421};
 422
 423/* device layer */
 424
 425static const struct usb_device_id diolan_u2c_table[] = {
 426        { USB_DEVICE(USB_VENDOR_ID_DIOLAN, USB_DEVICE_ID_DIOLAN_U2C) },
 427        { }
 428};
 429
 430MODULE_DEVICE_TABLE(usb, diolan_u2c_table);
 431
 432static void diolan_u2c_free(struct i2c_diolan_u2c *dev)
 433{
 434        usb_put_dev(dev->usb_dev);
 435        kfree(dev);
 436}
 437
 438static int diolan_u2c_probe(struct usb_interface *interface,
 439                            const struct usb_device_id *id)
 440{
 441        struct usb_host_interface *hostif = interface->cur_altsetting;
 442        struct i2c_diolan_u2c *dev;
 443        int ret;
 444
 445        if (hostif->desc.bInterfaceNumber != 0
 446            || hostif->desc.bNumEndpoints < 2)
 447                return -ENODEV;
 448
 449        /* allocate memory for our device state and initialize it */
 450        dev = kzalloc(sizeof(*dev), GFP_KERNEL);
 451        if (dev == NULL) {
 452                ret = -ENOMEM;
 453                goto error;
 454        }
 455        dev->ep_out = hostif->endpoint[0].desc.bEndpointAddress;
 456        dev->ep_in = hostif->endpoint[1].desc.bEndpointAddress;
 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                goto error_free;
 486
 487        dev_dbg(&interface->dev, "connected " DRIVER_NAME "\n");
 488
 489        return 0;
 490
 491error_free:
 492        usb_set_intfdata(interface, NULL);
 493        diolan_u2c_free(dev);
 494error:
 495        return ret;
 496}
 497
 498static void diolan_u2c_disconnect(struct usb_interface *interface)
 499{
 500        struct i2c_diolan_u2c *dev = usb_get_intfdata(interface);
 501
 502        i2c_del_adapter(&dev->adapter);
 503        usb_set_intfdata(interface, NULL);
 504        diolan_u2c_free(dev);
 505
 506        dev_dbg(&interface->dev, "disconnected\n");
 507}
 508
 509static struct usb_driver diolan_u2c_driver = {
 510        .name = DRIVER_NAME,
 511        .probe = diolan_u2c_probe,
 512        .disconnect = diolan_u2c_disconnect,
 513        .id_table = diolan_u2c_table,
 514};
 515
 516module_usb_driver(diolan_u2c_driver);
 517
 518MODULE_AUTHOR("Guenter Roeck <linux@roeck-us.net>");
 519MODULE_DESCRIPTION(DRIVER_NAME " driver");
 520MODULE_LICENSE("GPL");
 521