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(s)         (1000000 / (2 * (s - 1) + 10))
  68
  69#define DIOLAN_USB_TIMEOUT      100     /* in ms */
  70#define DIOLAN_SYNC_TIMEOUT     20      /* in ms */
  71
  72#define DIOLAN_OUTBUF_LEN       128
  73#define DIOLAN_FLUSH_LEN        (DIOLAN_OUTBUF_LEN - 4)
  74#define DIOLAN_INBUF_LEN        256     /* Maximum supported receive length */
  75
  76/* Structure to hold all of our device specific stuff */
  77struct i2c_diolan_u2c {
  78        u8 obuffer[DIOLAN_OUTBUF_LEN];  /* output buffer */
  79        u8 ibuffer[DIOLAN_INBUF_LEN];   /* input buffer */
  80        int ep_in, ep_out;              /* Endpoints    */
  81        struct usb_device *usb_dev;     /* the usb device for this device */
  82        struct usb_interface *interface;/* the interface for this device */
  83        struct i2c_adapter adapter;     /* i2c related things */
  84        int olen;                       /* Output buffer length */
  85        int ocount;                     /* Number of enqueued messages */
  86};
  87
  88static uint frequency = I2C_MAX_STANDARD_MODE_FREQ;     /* I2C clock frequency in Hz */
  89
  90module_param(frequency, uint, S_IRUGO | S_IWUSR);
  91MODULE_PARM_DESC(frequency, "I2C clock frequency in hertz");
  92
  93/* usb layer */
  94
  95/* Send command to device, and get response. */
  96static int diolan_usb_transfer(struct i2c_diolan_u2c *dev)
  97{
  98        int ret = 0;
  99        int actual;
 100        int i;
 101
 102        if (!dev->olen || !dev->ocount)
 103                return -EINVAL;
 104
 105        ret = usb_bulk_msg(dev->usb_dev,
 106                           usb_sndbulkpipe(dev->usb_dev, dev->ep_out),
 107                           dev->obuffer, dev->olen, &actual,
 108                           DIOLAN_USB_TIMEOUT);
 109        if (!ret) {
 110                for (i = 0; i < dev->ocount; i++) {
 111                        int tmpret;
 112
 113                        tmpret = usb_bulk_msg(dev->usb_dev,
 114                                              usb_rcvbulkpipe(dev->usb_dev,
 115                                                              dev->ep_in),
 116                                              dev->ibuffer,
 117                                              sizeof(dev->ibuffer), &actual,
 118                                              DIOLAN_USB_TIMEOUT);
 119                        /*
 120                         * Stop command processing if a previous command
 121                         * returned an error.
 122                         * Note that we still need to retrieve all messages.
 123                         */
 124                        if (ret < 0)
 125                                continue;
 126                        ret = tmpret;
 127                        if (ret == 0 && actual > 0) {
 128                                switch (dev->ibuffer[actual - 1]) {
 129                                case RESP_NACK:
 130                                        /*
 131                                         * Return ENXIO if NACK was received as
 132                                         * response to the address phase,
 133                                         * EIO otherwise
 134                                         */
 135                                        ret = i == 1 ? -ENXIO : -EIO;
 136                                        break;
 137                                case RESP_TIMEOUT:
 138                                        ret = -ETIMEDOUT;
 139                                        break;
 140                                case RESP_OK:
 141                                        /* strip off return code */
 142                                        ret = actual - 1;
 143                                        break;
 144                                default:
 145                                        ret = -EIO;
 146                                        break;
 147                                }
 148                        }
 149                }
 150        }
 151        dev->olen = 0;
 152        dev->ocount = 0;
 153        return ret;
 154}
 155
 156static int diolan_write_cmd(struct i2c_diolan_u2c *dev, bool flush)
 157{
 158        if (flush || dev->olen >= DIOLAN_FLUSH_LEN)
 159                return diolan_usb_transfer(dev);
 160        return 0;
 161}
 162
 163/* Send command (no data) */
 164static int diolan_usb_cmd(struct i2c_diolan_u2c *dev, u8 command, bool flush)
 165{
 166        dev->obuffer[dev->olen++] = command;
 167        dev->ocount++;
 168        return diolan_write_cmd(dev, flush);
 169}
 170
 171/* Send command with one byte of data */
 172static int diolan_usb_cmd_data(struct i2c_diolan_u2c *dev, u8 command, u8 data,
 173                               bool flush)
 174{
 175        dev->obuffer[dev->olen++] = command;
 176        dev->obuffer[dev->olen++] = data;
 177        dev->ocount++;
 178        return diolan_write_cmd(dev, flush);
 179}
 180
 181/* Send command with two bytes of data */
 182static int diolan_usb_cmd_data2(struct i2c_diolan_u2c *dev, u8 command, u8 d1,
 183                                u8 d2, bool flush)
 184{
 185        dev->obuffer[dev->olen++] = command;
 186        dev->obuffer[dev->olen++] = d1;
 187        dev->obuffer[dev->olen++] = d2;
 188        dev->ocount++;
 189        return diolan_write_cmd(dev, flush);
 190}
 191
 192/*
 193 * Flush input queue.
 194 * If we don't do this at startup and the controller has queued up
 195 * messages which were not retrieved, it will stop responding
 196 * at some point.
 197 */
 198static void diolan_flush_input(struct i2c_diolan_u2c *dev)
 199{
 200        int i;
 201
 202        for (i = 0; i < 10; i++) {
 203                int actual = 0;
 204                int ret;
 205
 206                ret = usb_bulk_msg(dev->usb_dev,
 207                                   usb_rcvbulkpipe(dev->usb_dev, dev->ep_in),
 208                                   dev->ibuffer, sizeof(dev->ibuffer), &actual,
 209                                   DIOLAN_USB_TIMEOUT);
 210                if (ret < 0 || actual == 0)
 211                        break;
 212        }
 213        if (i == 10)
 214                dev_err(&dev->interface->dev, "Failed to flush input buffer\n");
 215}
 216
 217static int diolan_i2c_start(struct i2c_diolan_u2c *dev)
 218{
 219        return diolan_usb_cmd(dev, CMD_I2C_START, false);
 220}
 221
 222static int diolan_i2c_repeated_start(struct i2c_diolan_u2c *dev)
 223{
 224        return diolan_usb_cmd(dev, CMD_I2C_REPEATED_START, false);
 225}
 226
 227static int diolan_i2c_stop(struct i2c_diolan_u2c *dev)
 228{
 229        return diolan_usb_cmd(dev, CMD_I2C_STOP, true);
 230}
 231
 232static int diolan_i2c_get_byte_ack(struct i2c_diolan_u2c *dev, bool ack,
 233                                   u8 *byte)
 234{
 235        int ret;
 236
 237        ret = diolan_usb_cmd_data(dev, CMD_I2C_GET_BYTE_ACK, ack, true);
 238        if (ret > 0)
 239                *byte = dev->ibuffer[0];
 240        else if (ret == 0)
 241                ret = -EIO;
 242
 243        return ret;
 244}
 245
 246static int diolan_i2c_put_byte_ack(struct i2c_diolan_u2c *dev, u8 byte)
 247{
 248        return diolan_usb_cmd_data(dev, CMD_I2C_PUT_BYTE_ACK, byte, false);
 249}
 250
 251static int diolan_set_speed(struct i2c_diolan_u2c *dev, u8 speed)
 252{
 253        return diolan_usb_cmd_data(dev, CMD_I2C_SET_SPEED, speed, true);
 254}
 255
 256/* Enable or disable clock synchronization (stretching) */
 257static int diolan_set_clock_synch(struct i2c_diolan_u2c *dev, bool enable)
 258{
 259        return diolan_usb_cmd_data(dev, CMD_I2C_SET_CLK_SYNC, enable, true);
 260}
 261
 262/* Set clock synchronization timeout in ms */
 263static int diolan_set_clock_synch_timeout(struct i2c_diolan_u2c *dev, int ms)
 264{
 265        int to_val = ms * 10;
 266
 267        return diolan_usb_cmd_data2(dev, CMD_I2C_SET_CLK_SYNC_TO,
 268                                    to_val & 0xff, (to_val >> 8) & 0xff, true);
 269}
 270
 271static void diolan_fw_version(struct i2c_diolan_u2c *dev)
 272{
 273        int ret;
 274
 275        ret = diolan_usb_cmd(dev, CMD_GET_FW_VERSION, true);
 276        if (ret >= 2)
 277                dev_info(&dev->interface->dev,
 278                         "Diolan U2C firmware version %u.%u\n",
 279                         (unsigned int)dev->ibuffer[0],
 280                         (unsigned int)dev->ibuffer[1]);
 281}
 282
 283static void diolan_get_serial(struct i2c_diolan_u2c *dev)
 284{
 285        int ret;
 286        u32 serial;
 287
 288        ret = diolan_usb_cmd(dev, CMD_GET_SERIAL, true);
 289        if (ret >= 4) {
 290                serial = le32_to_cpu(*(u32 *)dev->ibuffer);
 291                dev_info(&dev->interface->dev,
 292                         "Diolan U2C serial number %u\n", serial);
 293        }
 294}
 295
 296static int diolan_init(struct i2c_diolan_u2c *dev)
 297{
 298        int speed, ret;
 299
 300        if (frequency >= 2 * I2C_MAX_STANDARD_MODE_FREQ) {
 301                speed = U2C_I2C_SPEED_FAST;
 302                frequency = I2C_MAX_FAST_MODE_FREQ;
 303        } else if (frequency >= I2C_MAX_STANDARD_MODE_FREQ || frequency == 0) {
 304                speed = U2C_I2C_SPEED_STD;
 305                frequency = I2C_MAX_STANDARD_MODE_FREQ;
 306        } else {
 307                speed = U2C_I2C_SPEED(frequency);
 308                if (speed > U2C_I2C_SPEED_2KHZ)
 309                        speed = U2C_I2C_SPEED_2KHZ;
 310                frequency = U2C_I2C_FREQ(speed);
 311        }
 312
 313        dev_info(&dev->interface->dev,
 314                 "Diolan U2C at USB bus %03d address %03d speed %d Hz\n",
 315                 dev->usb_dev->bus->busnum, dev->usb_dev->devnum, frequency);
 316
 317        diolan_flush_input(dev);
 318        diolan_fw_version(dev);
 319        diolan_get_serial(dev);
 320
 321        /* Set I2C speed */
 322        ret = diolan_set_speed(dev, speed);
 323        if (ret < 0)
 324                return ret;
 325
 326        /* Configure I2C clock synchronization */
 327        ret = diolan_set_clock_synch(dev, speed != U2C_I2C_SPEED_FAST);
 328        if (ret < 0)
 329                return ret;
 330
 331        if (speed != U2C_I2C_SPEED_FAST)
 332                ret = diolan_set_clock_synch_timeout(dev, DIOLAN_SYNC_TIMEOUT);
 333
 334        return ret;
 335}
 336
 337/* i2c layer */
 338
 339static int diolan_usb_xfer(struct i2c_adapter *adapter, struct i2c_msg *msgs,
 340                           int num)
 341{
 342        struct i2c_diolan_u2c *dev = i2c_get_adapdata(adapter);
 343        struct i2c_msg *pmsg;
 344        int i, j;
 345        int ret, sret;
 346
 347        ret = diolan_i2c_start(dev);
 348        if (ret < 0)
 349                return ret;
 350
 351        for (i = 0; i < num; i++) {
 352                pmsg = &msgs[i];
 353                if (i) {
 354                        ret = diolan_i2c_repeated_start(dev);
 355                        if (ret < 0)
 356                                goto abort;
 357                }
 358                ret = diolan_i2c_put_byte_ack(dev,
 359                                              i2c_8bit_addr_from_msg(pmsg));
 360                if (ret < 0)
 361                        goto abort;
 362                if (pmsg->flags & I2C_M_RD) {
 363                        for (j = 0; j < pmsg->len; j++) {
 364                                u8 byte;
 365                                bool ack = j < pmsg->len - 1;
 366
 367                                /*
 368                                 * Don't send NACK if this is the first byte
 369                                 * of a SMBUS_BLOCK message.
 370                                 */
 371                                if (j == 0 && (pmsg->flags & I2C_M_RECV_LEN))
 372                                        ack = true;
 373
 374                                ret = diolan_i2c_get_byte_ack(dev, ack, &byte);
 375                                if (ret < 0)
 376                                        goto abort;
 377                                /*
 378                                 * Adjust count if first received byte is length
 379                                 */
 380                                if (j == 0 && (pmsg->flags & I2C_M_RECV_LEN)) {
 381                                        if (byte == 0
 382                                            || byte > I2C_SMBUS_BLOCK_MAX) {
 383                                                ret = -EPROTO;
 384                                                goto abort;
 385                                        }
 386                                        pmsg->len += byte;
 387                                }
 388                                pmsg->buf[j] = byte;
 389                        }
 390                } else {
 391                        for (j = 0; j < pmsg->len; j++) {
 392                                ret = diolan_i2c_put_byte_ack(dev,
 393                                                              pmsg->buf[j]);
 394                                if (ret < 0)
 395                                        goto abort;
 396                        }
 397                }
 398        }
 399        ret = num;
 400abort:
 401        sret = diolan_i2c_stop(dev);
 402        if (sret < 0 && ret >= 0)
 403                ret = sret;
 404        return ret;
 405}
 406
 407/*
 408 * Return list of supported functionality.
 409 */
 410static u32 diolan_usb_func(struct i2c_adapter *a)
 411{
 412        return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL |
 413               I2C_FUNC_SMBUS_READ_BLOCK_DATA | I2C_FUNC_SMBUS_BLOCK_PROC_CALL;
 414}
 415
 416static const struct i2c_algorithm diolan_usb_algorithm = {
 417        .master_xfer = diolan_usb_xfer,
 418        .functionality = diolan_usb_func,
 419};
 420
 421/* device layer */
 422
 423static const struct usb_device_id diolan_u2c_table[] = {
 424        { USB_DEVICE(USB_VENDOR_ID_DIOLAN, USB_DEVICE_ID_DIOLAN_U2C) },
 425        { }
 426};
 427
 428MODULE_DEVICE_TABLE(usb, diolan_u2c_table);
 429
 430static void diolan_u2c_free(struct i2c_diolan_u2c *dev)
 431{
 432        usb_put_dev(dev->usb_dev);
 433        kfree(dev);
 434}
 435
 436static int diolan_u2c_probe(struct usb_interface *interface,
 437                            const struct usb_device_id *id)
 438{
 439        struct usb_host_interface *hostif = interface->cur_altsetting;
 440        struct i2c_diolan_u2c *dev;
 441        int ret;
 442
 443        if (hostif->desc.bInterfaceNumber != 0
 444            || hostif->desc.bNumEndpoints < 2)
 445                return -ENODEV;
 446
 447        /* allocate memory for our device state and initialize it */
 448        dev = kzalloc(sizeof(*dev), GFP_KERNEL);
 449        if (dev == NULL) {
 450                ret = -ENOMEM;
 451                goto error;
 452        }
 453        dev->ep_out = hostif->endpoint[0].desc.bEndpointAddress;
 454        dev->ep_in = hostif->endpoint[1].desc.bEndpointAddress;
 455
 456        dev->usb_dev = usb_get_dev(interface_to_usbdev(interface));
 457        dev->interface = interface;
 458
 459        /* save our data pointer in this interface device */
 460        usb_set_intfdata(interface, dev);
 461
 462        /* setup i2c adapter description */
 463        dev->adapter.owner = THIS_MODULE;
 464        dev->adapter.class = I2C_CLASS_HWMON;
 465        dev->adapter.algo = &diolan_usb_algorithm;
 466        i2c_set_adapdata(&dev->adapter, dev);
 467        snprintf(dev->adapter.name, sizeof(dev->adapter.name),
 468                 DRIVER_NAME " at bus %03d device %03d",
 469                 dev->usb_dev->bus->busnum, dev->usb_dev->devnum);
 470
 471        dev->adapter.dev.parent = &dev->interface->dev;
 472
 473        /* initialize diolan i2c interface */
 474        ret = diolan_init(dev);
 475        if (ret < 0) {
 476                dev_err(&interface->dev, "failed to initialize adapter\n");
 477                goto error_free;
 478        }
 479
 480        /* and finally attach to i2c layer */
 481        ret = i2c_add_adapter(&dev->adapter);
 482        if (ret < 0)
 483                goto error_free;
 484
 485        dev_dbg(&interface->dev, "connected " DRIVER_NAME "\n");
 486
 487        return 0;
 488
 489error_free:
 490        usb_set_intfdata(interface, NULL);
 491        diolan_u2c_free(dev);
 492error:
 493        return ret;
 494}
 495
 496static void diolan_u2c_disconnect(struct usb_interface *interface)
 497{
 498        struct i2c_diolan_u2c *dev = usb_get_intfdata(interface);
 499
 500        i2c_del_adapter(&dev->adapter);
 501        usb_set_intfdata(interface, NULL);
 502        diolan_u2c_free(dev);
 503
 504        dev_dbg(&interface->dev, "disconnected\n");
 505}
 506
 507static struct usb_driver diolan_u2c_driver = {
 508        .name = DRIVER_NAME,
 509        .probe = diolan_u2c_probe,
 510        .disconnect = diolan_u2c_disconnect,
 511        .id_table = diolan_u2c_table,
 512};
 513
 514module_usb_driver(diolan_u2c_driver);
 515
 516MODULE_AUTHOR("Guenter Roeck <linux@roeck-us.net>");
 517MODULE_DESCRIPTION(DRIVER_NAME " driver");
 518MODULE_LICENSE("GPL");
 519