drivers/i2c/busses/scx200_acb.c

   1 /*
   2     Copyright (c) 2001,2002 Christer Weinigel <wingel@nano-system.com>
   3
   4     National Semiconductor SCx200 ACCESS.bus support
   5     Also supports the AMD CS5535 and AMD CS5536
   6
   7     Based on i2c-keywest.c which is:
   8         Copyright (c) 2001 Benjamin Herrenschmidt <benh@kernel.crashing.org>
   9         Copyright (c) 2000 Philip Edelbrock <phil@stimpy.netroedge.com>
  10
  11     This program is free software; you can redistribute it and/or
  12     modify it under the terms of the GNU General Public License as
  13     published by the Free Software Foundation; either version 2 of the
  14     License, or (at your option) any later version.
  15
  16     This program is distributed in the hope that it will be useful,
  17     but WITHOUT ANY WARRANTY; without even the implied warranty of
  18     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  19     General Public License for more details.
  20
  21     You should have received a copy of the GNU General Public License
  22     along with this program; if not, write to the Free Software
  23     Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  24 */
  25
  26 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  27
  28 #include <linux/module.h>
  29 #include <linux/errno.h>
  30 #include <linux/kernel.h>
  31 #include <linux/init.h>
  32 #include <linux/i2c.h>
  33 #include <linux/pci.h>
  34 #include <linux/platform_device.h>
  35 #include <linux/delay.h>
  36 #include <linux/mutex.h>
  37 #include <linux/slab.h>
  38 #include <linux/io.h>
  39
  40 #include <linux/scx200.h>
  41
  42 MODULE_AUTHOR("Christer Weinigel <wingel@nano-system.com>");
  43 MODULE_DESCRIPTION("NatSemi SCx200 ACCESS.bus Driver");
  44 MODULE_ALIAS("platform:cs5535-smb");
  45 MODULE_LICENSE("GPL");
  46
  47 #define MAX_DEVICES 4
  48 static int base[MAX_DEVICES] = { 0x820, 0x840 };
  49 module_param_array(base, int, NULL, 0);
  50 MODULE_PARM_DESC(base, "Base addresses for the ACCESS.bus controllers");
  51
  52 #define POLL_TIMEOUT    (HZ/5)
  53
  54 enum scx200_acb_state {
  55         state_idle,
  56         state_address,
  57         state_command,
  58         state_repeat_start,
  59         state_quick,
  60         state_read,
  61         state_write,
  62 };
  63
  64 static const char *scx200_acb_state_name[] = {
  65         "idle",
  66         "address",
  67         "command",
  68         "repeat_start",
  69         "quick",
  70         "read",
  71         "write",
  72 };
  73
  74 /* Physical interface */
  75 struct scx200_acb_iface {
  76         struct scx200_acb_iface *next;
  77         struct i2c_adapter adapter;
  78         unsigned base;
  79         struct mutex mutex;
  80
  81         /* State machine data */
  82         enum scx200_acb_state state;
  83         int result;
  84         u8 address_byte;
  85         u8 command;
  86         u8 *ptr;
  87         char needs_reset;
  88         unsigned len;
  89 };
  90
  91 /* Register Definitions */
  92 #define ACBSDA          (iface->base + 0)
  93 #define ACBST           (iface->base + 1)
  94 #define    ACBST_SDAST          0x40 /* SDA Status */
  95 #define    ACBST_BER            0x20
  96 #define    ACBST_NEGACK         0x10 /* Negative Acknowledge */
  97 #define    ACBST_STASTR         0x08 /* Stall After Start */
  98 #define    ACBST_MASTER         0x02
  99 #define ACBCST          (iface->base + 2)
 100 #define    ACBCST_BB            0x02
 101 #define ACBCTL1         (iface->base + 3)
 102 #define    ACBCTL1_STASTRE      0x80
 103 #define    ACBCTL1_NMINTE       0x40
 104 #define    ACBCTL1_ACK          0x10
 105 #define    ACBCTL1_STOP         0x02
 106 #define    ACBCTL1_START        0x01
 107 #define ACBADDR         (iface->base + 4)
 108 #define ACBCTL2         (iface->base + 5)
 109 #define    ACBCTL2_ENABLE       0x01
 110
 111 /************************************************************************/
 112
 113 static void scx200_acb_machine(struct scx200_acb_iface *iface, u8 status)
 114 {
 115         const char *errmsg;
 116
 117         dev_dbg(&iface->adapter.dev, "state %s, status = 0x%02x\n",
 118                 scx200_acb_state_name[iface->state], status);
 119
 120         if (status & ACBST_BER) {
 121                 errmsg = "bus error";
 122                 goto error;
 123         }
 124         if (!(status & ACBST_MASTER)) {
 125                 errmsg = "not master";
 126                 goto error;
 127         }
 128         if (status & ACBST_NEGACK) {
 129                 dev_dbg(&iface->adapter.dev, "negative ack in state %s\n",
 130                         scx200_acb_state_name[iface->state]);
 131
 132                 iface->state = state_idle;
 133                 iface->result = -ENXIO;
 134
 135                 outb(inb(ACBCTL1) | ACBCTL1_STOP, ACBCTL1);
 136                 outb(ACBST_STASTR | ACBST_NEGACK, ACBST);
 137
 138                 /* Reset the status register */
 139                 outb(0, ACBST);
 140                 return;
 141         }
 142
 143         switch (iface->state) {
 144         case state_idle:
 145                 dev_warn(&iface->adapter.dev, "interrupt in idle state\n");
 146                 break;
 147
 148         case state_address:
 149                 /* Do a pointer write first */
 150                 outb(iface->address_byte & ~1, ACBSDA);
 151
 152                 iface->state = state_command;
 153                 break;
 154
 155         case state_command:
 156                 outb(iface->command, ACBSDA);
 157
 158                 if (iface->address_byte & 1)
 159                         iface->state = state_repeat_start;
 160                 else
 161                         iface->state = state_write;
 162                 break;
 163
 164         case state_repeat_start:
 165                 outb(inb(ACBCTL1) | ACBCTL1_START, ACBCTL1);
 166                 /* fallthrough */
 167
 168         case state_quick:
 169                 if (iface->address_byte & 1) {
 170                         if (iface->len == 1)
 171                                 outb(inb(ACBCTL1) | ACBCTL1_ACK, ACBCTL1);
 172                         else
 173                                 outb(inb(ACBCTL1) & ~ACBCTL1_ACK, ACBCTL1);
 174                         outb(iface->address_byte, ACBSDA);
 175
 176                         iface->state = state_read;
 177                 } else {
 178                         outb(iface->address_byte, ACBSDA);
 179
 180                         iface->state = state_write;
 181                 }
 182                 break;
 183
 184         case state_read:
 185                 /* Set ACK if _next_ byte will be the last one */
 186                 if (iface->len == 2)
 187                         outb(inb(ACBCTL1) | ACBCTL1_ACK, ACBCTL1);
 188                 else
 189                         outb(inb(ACBCTL1) & ~ACBCTL1_ACK, ACBCTL1);
 190
 191                 if (iface->len == 1) {
 192                         iface->result = 0;
 193                         iface->state = state_idle;
 194                         outb(inb(ACBCTL1) | ACBCTL1_STOP, ACBCTL1);
 195                 }
 196
 197                 *iface->ptr++ = inb(ACBSDA);
 198                 --iface->len;
 199
 200                 break;
 201
 202         case state_write:
 203                 if (iface->len == 0) {
 204                         iface->result = 0;
 205                         iface->state = state_idle;
 206                         outb(inb(ACBCTL1) | ACBCTL1_STOP, ACBCTL1);
 207                         break;
 208                 }
 209
 210                 outb(*iface->ptr++, ACBSDA);
 211                 --iface->len;
 212
 213                 break;
 214         }
 215
 216         return;
 217
 218  error:
 219         dev_err(&iface->adapter.dev,
 220                 "%s in state %s (addr=0x%02x, len=%d, status=0x%02x)\n", errmsg,
 221                 scx200_acb_state_name[iface->state], iface->address_byte,
 222                 iface->len, status);
 223
 224         iface->state = state_idle;
 225         iface->result = -EIO;
 226         iface->needs_reset = 1;
 227 }
 228
 229 static void scx200_acb_poll(struct scx200_acb_iface *iface)
 230 {
 231         u8 status;
 232         unsigned long timeout;
 233
 234         timeout = jiffies + POLL_TIMEOUT;
 235         while (1) {
 236                 status = inb(ACBST);
 237
 238                 /* Reset the status register to avoid the hang */
 239                 outb(0, ACBST);
 240
 241                 if ((status & (ACBST_SDAST|ACBST_BER|ACBST_NEGACK)) != 0) {
 242                         scx200_acb_machine(iface, status);
 243                         return;
 244                 }
 245                 if (time_after(jiffies, timeout))
 246                         break;
 247                 cpu_relax();
 248                 cond_resched();
 249         }
 250
 251         dev_err(&iface->adapter.dev, "timeout in state %s\n",
 252                 scx200_acb_state_name[iface->state]);
 253
 254         iface->state = state_idle;
 255         iface->result = -EIO;
 256         iface->needs_reset = 1;
 257 }
 258
 259 static void scx200_acb_reset(struct scx200_acb_iface *iface)
 260 {
 261         /* Disable the ACCESS.bus device and Configure the SCL
 262            frequency: 16 clock cycles */
 263         outb(0x70, ACBCTL2);
 264         /* Polling mode */
 265         outb(0, ACBCTL1);
 266         /* Disable slave address */
 267         outb(0, ACBADDR);
 268         /* Enable the ACCESS.bus device */
 269         outb(inb(ACBCTL2) | ACBCTL2_ENABLE, ACBCTL2);
 270         /* Free STALL after START */
 271         outb(inb(ACBCTL1) & ~(ACBCTL1_STASTRE | ACBCTL1_NMINTE), ACBCTL1);
 272         /* Send a STOP */
 273         outb(inb(ACBCTL1) | ACBCTL1_STOP, ACBCTL1);
 274         /* Clear BER, NEGACK and STASTR bits */
 275         outb(ACBST_BER | ACBST_NEGACK | ACBST_STASTR, ACBST);
 276         /* Clear BB bit */
 277         outb(inb(ACBCST) | ACBCST_BB, ACBCST);
 278 }
 279
 280 static s32 scx200_acb_smbus_xfer(struct i2c_adapter *adapter,
 281                                  u16 address, unsigned short flags,
 282                                  char rw, u8 command, int size,
 283                                  union i2c_smbus_data *data)
 284 {
 285         struct scx200_acb_iface *iface = i2c_get_adapdata(adapter);
 286         int len;
 287         u8 *buffer;
 288         u16 cur_word;
 289         int rc;
 290
 291         switch (size) {
 292         case I2C_SMBUS_QUICK:
 293                 len = 0;
 294                 buffer = NULL;
 295                 break;
 296
 297         case I2C_SMBUS_BYTE:
 298                 len = 1;
 299                 buffer = rw ? &data->byte : &command;
 300                 break;
 301
 302         case I2C_SMBUS_BYTE_DATA:
 303                 len = 1;
 304                 buffer = &data->byte;
 305                 break;
 306
 307         case I2C_SMBUS_WORD_DATA:
 308                 len = 2;
 309                 cur_word = cpu_to_le16(data->word);
 310                 buffer = (u8 *)&cur_word;
 311                 break;
 312
 313         case I2C_SMBUS_I2C_BLOCK_DATA:
 314                 len = data->block[0];
 315                 if (len == 0 || len > I2C_SMBUS_BLOCK_MAX)
 316                         return -EINVAL;
 317                 buffer = &data->block[1];
 318                 break;
 319
 320         default:
 321                 return -EINVAL;
 322         }
 323
 324         dev_dbg(&adapter->dev,
 325                 "size=%d, address=0x%x, command=0x%x, len=%d, read=%d\n",
 326                 size, address, command, len, rw);
 327
 328         if (!len && rw == I2C_SMBUS_READ) {
 329                 dev_dbg(&adapter->dev, "zero length read\n");
 330                 return -EINVAL;
 331         }
 332
 333         mutex_lock(&iface->mutex);
 334
 335         iface->address_byte = (address << 1) | rw;
 336         iface->command = command;
 337         iface->ptr = buffer;
 338         iface->len = len;
 339         iface->result = -EINVAL;
 340         iface->needs_reset = 0;
 341
 342         outb(inb(ACBCTL1) | ACBCTL1_START, ACBCTL1);
 343
 344         if (size == I2C_SMBUS_QUICK || size == I2C_SMBUS_BYTE)
 345                 iface->state = state_quick;
 346         else
 347                 iface->state = state_address;
 348
 349         while (iface->state != state_idle)
 350                 scx200_acb_poll(iface);
 351
 352         if (iface->needs_reset)
 353                 scx200_acb_reset(iface);
 354
 355         rc = iface->result;
 356
 357         mutex_unlock(&iface->mutex);
 358
 359         if (rc == 0 && size == I2C_SMBUS_WORD_DATA && rw == I2C_SMBUS_READ)
 360                 data->word = le16_to_cpu(cur_word);
 361
 362 #ifdef DEBUG
 363         dev_dbg(&adapter->dev, "transfer done, result: %d", rc);
 364         if (buffer) {
 365                 int i;
 366                 printk(" data:");
 367                 for (i = 0; i < len; ++i)
 368                         printk(" %02x", buffer[i]);
 369         }
 370         printk("\n");
 371 #endif
 372
 373         return rc;
 374 }
 375
 376 static u32 scx200_acb_func(struct i2c_adapter *adapter)
 377 {
 378         return I2C_FUNC_SMBUS_QUICK | I2C_FUNC_SMBUS_BYTE |
 379                I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA |
 380                I2C_FUNC_SMBUS_I2C_BLOCK;
 381 }
 382
 383 /* For now, we only handle combined mode (smbus) */
 384 static const struct i2c_algorithm scx200_acb_algorithm = {
 385         .smbus_xfer     = scx200_acb_smbus_xfer,
 386         .functionality  = scx200_acb_func,
 387 };
 388
 389 static struct scx200_acb_iface *scx200_acb_list;
 390 static DEFINE_MUTEX(scx200_acb_list_mutex);
 391
 392 static int scx200_acb_probe(struct scx200_acb_iface *iface)
 393 {
 394         u8 val;
 395
 396         /* Disable the ACCESS.bus device and Configure the SCL
 397            frequency: 16 clock cycles */
 398         outb(0x70, ACBCTL2);
 399
 400         if (inb(ACBCTL2) != 0x70) {
 401                 pr_debug("ACBCTL2 readback failed\n");
 402                 return -ENXIO;
 403         }
 404
 405         outb(inb(ACBCTL1) | ACBCTL1_NMINTE, ACBCTL1);
 406
 407         val = inb(ACBCTL1);
 408         if (val) {
 409                 pr_debug("disabled, but ACBCTL1=0x%02x\n", val);
 410                 return -ENXIO;
 411         }
 412
 413         outb(inb(ACBCTL2) | ACBCTL2_ENABLE, ACBCTL2);
 414
 415         outb(inb(ACBCTL1) | ACBCTL1_NMINTE, ACBCTL1);
 416
 417         val = inb(ACBCTL1);
 418         if ((val & ACBCTL1_NMINTE) != ACBCTL1_NMINTE) {
 419                 pr_debug("enabled, but NMINTE won't be set, ACBCTL1=0x%02x\n",
 420                          val);
 421                 return -ENXIO;
 422         }
 423
 424         return 0;
 425 }
 426
 427 static struct scx200_acb_iface *scx200_create_iface(const char *text,
 428                 struct device *dev, int index)
 429 {
 430         struct scx200_acb_iface *iface;
 431         struct i2c_adapter *adapter;
 432
 433         iface = kzalloc(sizeof(*iface), GFP_KERNEL);
 434         if (!iface) {
 435                 pr_err("can't allocate memory\n");
 436                 return NULL;
 437         }
 438
 439         adapter = &iface->adapter;
 440         i2c_set_adapdata(adapter, iface);
 441         snprintf(adapter->name, sizeof(adapter->name), "%s ACB%d", text, index);
 442         adapter->owner = THIS_MODULE;
 443         adapter->algo = &scx200_acb_algorithm;
 444         adapter->class = I2C_CLASS_HWMON | I2C_CLASS_SPD;
 445         adapter->dev.parent = dev;
 446
 447         mutex_init(&iface->mutex);
 448
 449         return iface;
 450 }
 451
 452 static int scx200_acb_create(struct scx200_acb_iface *iface)
 453 {
 454         struct i2c_adapter *adapter;
 455         int rc;
 456
 457         adapter = &iface->adapter;
 458
 459         rc = scx200_acb_probe(iface);
 460         if (rc) {
 461                 pr_warn("probe failed\n");
 462                 return rc;
 463         }
 464
 465         scx200_acb_reset(iface);
 466
 467         if (i2c_add_adapter(adapter) < 0) {
 468                 pr_err("failed to register\n");
 469                 return -ENODEV;
 470         }
 471
 472         if (!adapter->dev.parent) {
 473                 /* If there's no dev, we're tracking (ISA) ifaces manually */
 474                 mutex_lock(&scx200_acb_list_mutex);
 475                 iface->next = scx200_acb_list;
 476                 scx200_acb_list = iface;
 477                 mutex_unlock(&scx200_acb_list_mutex);
 478         }
 479
 480         return 0;
 481 }
 482
 483 static struct scx200_acb_iface *scx200_create_dev(const char *text,
 484                 unsigned long base, int index, struct device *dev)
 485 {
 486         struct scx200_acb_iface *iface;
 487         int rc;
 488
 489         iface = scx200_create_iface(text, dev, index);
 490
 491         if (iface == NULL)
 492                 return NULL;
 493
 494         if (!request_region(base, 8, iface->adapter.name)) {
 495                 pr_err("can't allocate io 0x%lx-0x%lx\n", base, base + 8 - 1);
 496                 goto errout_free;
 497         }
 498
 499         iface->base = base;
 500         rc = scx200_acb_create(iface);
 501
 502         if (rc == 0)
 503                 return iface;
 504
 505         release_region(base, 8);
 506  errout_free:
 507         kfree(iface);
 508         return NULL;
 509 }
 510
 511 static int scx200_probe(struct platform_device *pdev)
 512 {
 513         struct scx200_acb_iface *iface;
 514         struct resource *res;
 515
 516         res = platform_get_resource(pdev, IORESOURCE_IO, 0);
 517         if (!res) {
 518                 dev_err(&pdev->dev, "can't fetch device resource info\n");
 519                 return -ENODEV;
 520         }
 521
 522         iface = scx200_create_dev("CS5535", res->start, 0, &pdev->dev);
 523         if (!iface)
 524                 return -EIO;
 525
 526         dev_info(&pdev->dev, "SCx200 device '%s' registered\n",
 527                         iface->adapter.name);
 528         platform_set_drvdata(pdev, iface);
 529
 530         return 0;
 531 }
 532
 533 static void scx200_cleanup_iface(struct scx200_acb_iface *iface)
 534 {
 535         i2c_del_adapter(&iface->adapter);
 536         release_region(iface->base, 8);
 537         kfree(iface);
 538 }
 539
 540 static int scx200_remove(struct platform_device *pdev)
 541 {
 542         struct scx200_acb_iface *iface;
 543
 544         iface = platform_get_drvdata(pdev);
 545         scx200_cleanup_iface(iface);
 546
 547         return 0;
 548 }
 549
 550 static struct platform_driver scx200_pci_driver = {
 551         .driver = {
 552                 .name = "cs5535-smb",
 553                 .owner = THIS_MODULE,
 554         },
 555         .probe = scx200_probe,
 556         .remove = scx200_remove,
 557 };
 558
 559 static DEFINE_PCI_DEVICE_TABLE(scx200_isa) = {
 560         { PCI_DEVICE(PCI_VENDOR_ID_NS, PCI_DEVICE_ID_NS_SCx200_BRIDGE) },
 561         { PCI_DEVICE(PCI_VENDOR_ID_NS, PCI_DEVICE_ID_NS_SC1100_BRIDGE) },
 562         { 0, }
 563 };
 564
 565 static __init void scx200_scan_isa(void)
 566 {
 567         int i;
 568
 569         if (!pci_dev_present(scx200_isa))
 570                 return;
 571
 572         for (i = 0; i < MAX_DEVICES; ++i) {
 573                 if (base[i] == 0)
 574                         continue;
 575
 576                 /* XXX: should we care about failures? */
 577                 scx200_create_dev("SCx200", base[i], i, NULL);
 578         }
 579 }
 580
 581 static int __init scx200_acb_init(void)
 582 {
 583         pr_debug("NatSemi SCx200 ACCESS.bus Driver\n");
 584
 585         /* First scan for ISA-based devices */
 586         scx200_scan_isa();      /* XXX: should we care about errors? */
 587
 588         /* If at least one bus was created, init must succeed */
 589         if (scx200_acb_list)
 590                 return 0;
 591
 592         /* No ISA devices; register the platform driver for PCI-based devices */
 593         return platform_driver_register(&scx200_pci_driver);
 594 }
 595
 596 static void __exit scx200_acb_cleanup(void)
 597 {
 598         struct scx200_acb_iface *iface;
 599
 600         platform_driver_unregister(&scx200_pci_driver);
 601
 602         mutex_lock(&scx200_acb_list_mutex);
 603         while ((iface = scx200_acb_list) != NULL) {
 604                 scx200_acb_list = iface->next;
 605                 mutex_unlock(&scx200_acb_list_mutex);
 606
 607                 scx200_cleanup_iface(iface);
 608
 609                 mutex_lock(&scx200_acb_list_mutex);
 610         }
 611         mutex_unlock(&scx200_acb_list_mutex);
 612 }
 613
 614 module_init(scx200_acb_init);
 615 module_exit(scx200_acb_cleanup);