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 */
  77 struct 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
  88 static uint frequency = I2C_MAX_STANDARD_MODE_FREQ;     /* I2C clock frequency in Hz */
  89
  90 module_param(frequency, uint, S_IRUGO | S_IWUSR);
  91 MODULE_PARM_DESC(frequency, "I2C clock frequency in hertz");
  92
  93 /* usb layer */
  94
  95 /* Send command to device, and get response. */
  96 static 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
 156 static 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) */
 164 static 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 */
 172 static 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 */
 182 static 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  */
 198 static 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
 217 static int diolan_i2c_start(struct i2c_diolan_u2c *dev)
 218 {
 219         return diolan_usb_cmd(dev, CMD_I2C_START, false);
 220 }
 221
 222 static int diolan_i2c_repeated_start(struct i2c_diolan_u2c *dev)
 223 {
 224         return diolan_usb_cmd(dev, CMD_I2C_REPEATED_START, false);
 225 }
 226
 227 static int diolan_i2c_stop(struct i2c_diolan_u2c *dev)
 228 {
 229         return diolan_usb_cmd(dev, CMD_I2C_STOP, true);
 230 }
 231
 232 static 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
 246 static 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
 251 static 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) */
 257 static 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 */
 263 static 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
 271 static 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
 283 static 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
 296 static 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
 339 static 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;
 400 abort:
 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  */
 410 static 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
 416 static const struct i2c_algorithm diolan_usb_algorithm = {
 417         .master_xfer = diolan_usb_xfer,
 418         .functionality = diolan_usb_func,
 419 };
 420
 421 /* device layer */
 422
 423 static const struct usb_device_id diolan_u2c_table[] = {
 424         { USB_DEVICE(USB_VENDOR_ID_DIOLAN, USB_DEVICE_ID_DIOLAN_U2C) },
 425         { }
 426 };
 427
 428 MODULE_DEVICE_TABLE(usb, diolan_u2c_table);
 429
 430 static void diolan_u2c_free(struct i2c_diolan_u2c *dev)
 431 {
 432         usb_put_dev(dev->usb_dev);
 433         kfree(dev);
 434 }
 435
 436 static 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
 489 error_free:
 490         usb_set_intfdata(interface, NULL);
 491         diolan_u2c_free(dev);
 492 error:
 493         return ret;
 494 }
 495
 496 static 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
 507 static 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
 514 module_usb_driver(diolan_u2c_driver);
 515
 516 MODULE_AUTHOR("Guenter Roeck <linux@roeck-us.net>");
 517 MODULE_DESCRIPTION(DRIVER_NAME " driver");
 518 MODULE_LICENSE("GPL");