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 #include <linux/module.h>
  27 #include <linux/errno.h>
  28 #include <linux/kernel.h>
  29 #include <linux/init.h>
  30 #include <linux/i2c.h>
  31 #include <linux/pci.h>
  32 #include <linux/delay.h>
  33 #include <linux/mutex.h>
  34 #include <asm/io.h>
  35
  36 #include <linux/scx200.h>
  37
  38 #define NAME "scx200_acb"
  39
  40 MODULE_AUTHOR("Christer Weinigel <wingel@nano-system.com>");
  41 MODULE_DESCRIPTION("NatSemi SCx200 ACCESS.bus Driver");
  42 MODULE_LICENSE("GPL");
  43
  44 #define MAX_DEVICES 4
  45 static int base[MAX_DEVICES] = { 0x820, 0x840 };
  46 module_param_array(base, int, NULL, 0);
  47 MODULE_PARM_DESC(base, "Base addresses for the ACCESS.bus controllers");
  48
  49 #define POLL_TIMEOUT    (HZ/5)
  50
  51 enum scx200_acb_state {
  52         state_idle,
  53         state_address,
  54         state_command,
  55         state_repeat_start,
  56         state_quick,
  57         state_read,
  58         state_write,
  59 };
  60
  61 static const char *scx200_acb_state_name[] = {
  62         "idle",
  63         "address",
  64         "command",
  65         "repeat_start",
  66         "quick",
  67         "read",
  68         "write",
  69 };
  70
  71 /* Physical interface */
  72 struct scx200_acb_iface {
  73         struct scx200_acb_iface *next;
  74         struct i2c_adapter adapter;
  75         unsigned base;
  76         struct mutex mutex;
  77
  78         /* State machine data */
  79         enum scx200_acb_state state;
  80         int result;
  81         u8 address_byte;
  82         u8 command;
  83         u8 *ptr;
  84         char needs_reset;
  85         unsigned len;
  86
  87         /* PCI device info */
  88         struct pci_dev *pdev;
  89         int bar;
  90 };
  91
  92 /* Register Definitions */
  93 #define ACBSDA          (iface->base + 0)
  94 #define ACBST           (iface->base + 1)
  95 #define    ACBST_SDAST          0x40 /* SDA Status */
  96 #define    ACBST_BER            0x20
  97 #define    ACBST_NEGACK         0x10 /* Negative Acknowledge */
  98 #define    ACBST_STASTR         0x08 /* Stall After Start */
  99 #define    ACBST_MASTER         0x02
 100 #define ACBCST          (iface->base + 2)
 101 #define    ACBCST_BB            0x02
 102 #define ACBCTL1         (iface->base + 3)
 103 #define    ACBCTL1_STASTRE      0x80
 104 #define    ACBCTL1_NMINTE       0x40
 105 #define    ACBCTL1_ACK          0x10
 106 #define    ACBCTL1_STOP         0x02
 107 #define    ACBCTL1_START        0x01
 108 #define ACBADDR         (iface->base + 4)
 109 #define ACBCTL2         (iface->base + 5)
 110 #define    ACBCTL2_ENABLE       0x01
 111
 112 /************************************************************************/
 113
 114 static void scx200_acb_machine(struct scx200_acb_iface *iface, u8 status)
 115 {
 116         const char *errmsg;
 117
 118         dev_dbg(&iface->adapter.dev, "state %s, status = 0x%02x\n",
 119                 scx200_acb_state_name[iface->state], status);
 120
 121         if (status & ACBST_BER) {
 122                 errmsg = "bus error";
 123                 goto error;
 124         }
 125         if (!(status & ACBST_MASTER)) {
 126                 errmsg = "not master";
 127                 goto error;
 128         }
 129         if (status & ACBST_NEGACK) {
 130                 dev_dbg(&iface->adapter.dev, "negative ack in state %s\n",
 131                         scx200_acb_state_name[iface->state]);
 132
 133                 iface->state = state_idle;
 134                 iface->result = -ENXIO;
 135
 136                 outb(inb(ACBCTL1) | ACBCTL1_STOP, ACBCTL1);
 137                 outb(ACBST_STASTR | ACBST_NEGACK, ACBST);
 138
 139                 /* Reset the status register */
 140                 outb(0, ACBST);
 141                 return;
 142         }
 143
 144         switch (iface->state) {
 145         case state_idle:
 146                 dev_warn(&iface->adapter.dev, "interrupt in idle state\n");
 147                 break;
 148
 149         case state_address:
 150                 /* Do a pointer write first */
 151                 outb(iface->address_byte & ~1, ACBSDA);
 152
 153                 iface->state = state_command;
 154                 break;
 155
 156         case state_command:
 157                 outb(iface->command, ACBSDA);
 158
 159                 if (iface->address_byte & 1)
 160                         iface->state = state_repeat_start;
 161                 else
 162                         iface->state = state_write;
 163                 break;
 164
 165         case state_repeat_start:
 166                 outb(inb(ACBCTL1) | ACBCTL1_START, ACBCTL1);
 167                 /* fallthrough */
 168
 169         case state_quick:
 170                 if (iface->address_byte & 1) {
 171                         if (iface->len == 1)
 172                                 outb(inb(ACBCTL1) | ACBCTL1_ACK, ACBCTL1);
 173                         else
 174                                 outb(inb(ACBCTL1) & ~ACBCTL1_ACK, ACBCTL1);
 175                         outb(iface->address_byte, ACBSDA);
 176
 177                         iface->state = state_read;
 178                 } else {
 179                         outb(iface->address_byte, ACBSDA);
 180
 181                         iface->state = state_write;
 182                 }
 183                 break;
 184
 185         case state_read:
 186                 /* Set ACK if _next_ byte will be the last one */
 187                 if (iface->len == 2)
 188                         outb(inb(ACBCTL1) | ACBCTL1_ACK, ACBCTL1);
 189                 else
 190                         outb(inb(ACBCTL1) & ~ACBCTL1_ACK, ACBCTL1);
 191
 192                 if (iface->len == 1) {
 193                         iface->result = 0;
 194                         iface->state = state_idle;
 195                         outb(inb(ACBCTL1) | ACBCTL1_STOP, ACBCTL1);
 196                 }
 197
 198                 *iface->ptr++ = inb(ACBSDA);
 199                 --iface->len;
 200
 201                 break;
 202
 203         case state_write:
 204                 if (iface->len == 0) {
 205                         iface->result = 0;
 206                         iface->state = state_idle;
 207                         outb(inb(ACBCTL1) | ACBCTL1_STOP, ACBCTL1);
 208                         break;
 209                 }
 210
 211                 outb(*iface->ptr++, ACBSDA);
 212                 --iface->len;
 213
 214                 break;
 215         }
 216
 217         return;
 218
 219  error:
 220         dev_err(&iface->adapter.dev, "%s in state %s\n", errmsg,
 221                 scx200_acb_state_name[iface->state]);
 222
 223         iface->state = state_idle;
 224         iface->result = -EIO;
 225         iface->needs_reset = 1;
 226 }
 227
 228 static void scx200_acb_poll(struct scx200_acb_iface *iface)
 229 {
 230         u8 status;
 231         unsigned long timeout;
 232
 233         timeout = jiffies + POLL_TIMEOUT;
 234         while (1) {
 235                 status = inb(ACBST);
 236
 237                 /* Reset the status register to avoid the hang */
 238                 outb(0, ACBST);
 239
 240                 if ((status & (ACBST_SDAST|ACBST_BER|ACBST_NEGACK)) != 0) {
 241                         scx200_acb_machine(iface, status);
 242                         return;
 243                 }
 244                 if (time_after(jiffies, timeout))
 245                         break;
 246                 cpu_relax();
 247                 cond_resched();
 248         }
 249
 250         dev_err(&iface->adapter.dev, "timeout in state %s\n",
 251                 scx200_acb_state_name[iface->state]);
 252
 253         iface->state = state_idle;
 254         iface->result = -EIO;
 255         iface->needs_reset = 1;
 256 }
 257
 258 static void scx200_acb_reset(struct scx200_acb_iface *iface)
 259 {
 260         /* Disable the ACCESS.bus device and Configure the SCL
 261            frequency: 16 clock cycles */
 262         outb(0x70, ACBCTL2);
 263         /* Polling mode */
 264         outb(0, ACBCTL1);
 265         /* Disable slave address */
 266         outb(0, ACBADDR);
 267         /* Enable the ACCESS.bus device */
 268         outb(inb(ACBCTL2) | ACBCTL2_ENABLE, ACBCTL2);
 269         /* Free STALL after START */
 270         outb(inb(ACBCTL1) & ~(ACBCTL1_STASTRE | ACBCTL1_NMINTE), ACBCTL1);
 271         /* Send a STOP */
 272         outb(inb(ACBCTL1) | ACBCTL1_STOP, ACBCTL1);
 273         /* Clear BER, NEGACK and STASTR bits */
 274         outb(ACBST_BER | ACBST_NEGACK | ACBST_STASTR, ACBST);
 275         /* Clear BB bit */
 276         outb(inb(ACBCST) | ACBCST_BB, ACBCST);
 277 }
 278
 279 static s32 scx200_acb_smbus_xfer(struct i2c_adapter *adapter,
 280                                  u16 address, unsigned short flags,
 281                                  char rw, u8 command, int size,
 282                                  union i2c_smbus_data *data)
 283 {
 284         struct scx200_acb_iface *iface = i2c_get_adapdata(adapter);
 285         int len;
 286         u8 *buffer;
 287         u16 cur_word;
 288         int rc;
 289
 290         switch (size) {
 291         case I2C_SMBUS_QUICK:
 292                 len = 0;
 293                 buffer = NULL;
 294                 break;
 295
 296         case I2C_SMBUS_BYTE:
 297                 len = 1;
 298                 buffer = rw ? &data->byte : &command;
 299                 break;
 300
 301         case I2C_SMBUS_BYTE_DATA:
 302                 len = 1;
 303                 buffer = &data->byte;
 304                 break;
 305
 306         case I2C_SMBUS_WORD_DATA:
 307                 len = 2;
 308                 cur_word = cpu_to_le16(data->word);
 309                 buffer = (u8 *)&cur_word;
 310                 break;
 311
 312         case I2C_SMBUS_I2C_BLOCK_DATA:
 313                 len = data->block[0];
 314                 if (len == 0 || len > I2C_SMBUS_BLOCK_MAX)
 315                         return -EINVAL;
 316                 buffer = &data->block[1];
 317                 break;
 318
 319         default:
 320                 return -EINVAL;
 321         }
 322
 323         dev_dbg(&adapter->dev,
 324                 "size=%d, address=0x%x, command=0x%x, len=%d, read=%d\n",
 325                 size, address, command, len, rw);
 326
 327         if (!len && rw == I2C_SMBUS_READ) {
 328                 dev_dbg(&adapter->dev, "zero length read\n");
 329                 return -EINVAL;
 330         }
 331
 332         mutex_lock(&iface->mutex);
 333
 334         iface->address_byte = (address << 1) | rw;
 335         iface->command = command;
 336         iface->ptr = buffer;
 337         iface->len = len;
 338         iface->result = -EINVAL;
 339         iface->needs_reset = 0;
 340
 341         outb(inb(ACBCTL1) | ACBCTL1_START, ACBCTL1);
 342
 343         if (size == I2C_SMBUS_QUICK || size == I2C_SMBUS_BYTE)
 344                 iface->state = state_quick;
 345         else
 346                 iface->state = state_address;
 347
 348         while (iface->state != state_idle)
 349                 scx200_acb_poll(iface);
 350
 351         if (iface->needs_reset)
 352                 scx200_acb_reset(iface);
 353
 354         rc = iface->result;
 355
 356         mutex_unlock(&iface->mutex);
 357
 358         if (rc == 0 && size == I2C_SMBUS_WORD_DATA && rw == I2C_SMBUS_READ)
 359                 data->word = le16_to_cpu(cur_word);
 360
 361 #ifdef DEBUG
 362         dev_dbg(&adapter->dev, "transfer done, result: %d", rc);
 363         if (buffer) {
 364                 int i;
 365                 printk(" data:");
 366                 for (i = 0; i < len; ++i)
 367                         printk(" %02x", buffer[i]);
 368         }
 369         printk("\n");
 370 #endif
 371
 372         return rc;
 373 }
 374
 375 static u32 scx200_acb_func(struct i2c_adapter *adapter)
 376 {
 377         return I2C_FUNC_SMBUS_QUICK | I2C_FUNC_SMBUS_BYTE |
 378                I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA |
 379                I2C_FUNC_SMBUS_I2C_BLOCK;
 380 }
 381
 382 /* For now, we only handle combined mode (smbus) */
 383 static const struct i2c_algorithm scx200_acb_algorithm = {
 384         .smbus_xfer     = scx200_acb_smbus_xfer,
 385         .functionality  = scx200_acb_func,
 386 };
 387
 388 static struct scx200_acb_iface *scx200_acb_list;
 389 static DEFINE_MUTEX(scx200_acb_list_mutex);
 390
 391 static __init int scx200_acb_probe(struct scx200_acb_iface *iface)
 392 {
 393         u8 val;
 394
 395         /* Disable the ACCESS.bus device and Configure the SCL
 396            frequency: 16 clock cycles */
 397         outb(0x70, ACBCTL2);
 398
 399         if (inb(ACBCTL2) != 0x70) {
 400                 pr_debug(NAME ": ACBCTL2 readback failed\n");
 401                 return -ENXIO;
 402         }
 403
 404         outb(inb(ACBCTL1) | ACBCTL1_NMINTE, ACBCTL1);
 405
 406         val = inb(ACBCTL1);
 407         if (val) {
 408                 pr_debug(NAME ": disabled, but ACBCTL1=0x%02x\n",
 409                         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(NAME ": enabled, but NMINTE won't be set, "
 420                          "ACBCTL1=0x%02x\n", val);
 421                 return -ENXIO;
 422         }
 423
 424         return 0;
 425 }
 426
 427 static __init 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                 printk(KERN_ERR NAME ": 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->id = I2C_HW_SMBUS_SCX200;
 444         adapter->algo = &scx200_acb_algorithm;
 445         adapter->class = I2C_CLASS_HWMON | I2C_CLASS_SPD;
 446         adapter->dev.parent = dev;
 447
 448         mutex_init(&iface->mutex);
 449
 450         return iface;
 451 }
 452
 453 static int __init scx200_acb_create(struct scx200_acb_iface *iface)
 454 {
 455         struct i2c_adapter *adapter;
 456         int rc;
 457
 458         adapter = &iface->adapter;
 459
 460         rc = scx200_acb_probe(iface);
 461         if (rc) {
 462                 printk(KERN_WARNING NAME ": probe failed\n");
 463                 return rc;
 464         }
 465
 466         scx200_acb_reset(iface);
 467
 468         if (i2c_add_adapter(adapter) < 0) {
 469                 printk(KERN_ERR NAME ": failed to register\n");
 470                 return -ENODEV;
 471         }
 472
 473         mutex_lock(&scx200_acb_list_mutex);
 474         iface->next = scx200_acb_list;
 475         scx200_acb_list = iface;
 476         mutex_unlock(&scx200_acb_list_mutex);
 477
 478         return 0;
 479 }
 480
 481 static __init int scx200_create_pci(const char *text, struct pci_dev *pdev,
 482                 int bar)
 483 {
 484         struct scx200_acb_iface *iface;
 485         int rc;
 486
 487         iface = scx200_create_iface(text, &pdev->dev, 0);
 488
 489         if (iface == NULL)
 490                 return -ENOMEM;
 491
 492         iface->pdev = pdev;
 493         iface->bar = bar;
 494
 495         rc = pci_enable_device_io(iface->pdev);
 496         if (rc)
 497                 goto errout_free;
 498
 499         rc = pci_request_region(iface->pdev, iface->bar, iface->adapter.name);
 500         if (rc) {
 501                 printk(KERN_ERR NAME ": can't allocate PCI BAR %d\n",
 502                                 iface->bar);
 503                 goto errout_free;
 504         }
 505
 506         iface->base = pci_resource_start(iface->pdev, iface->bar);
 507         rc = scx200_acb_create(iface);
 508
 509         if (rc == 0)
 510                 return 0;
 511
 512         pci_release_region(iface->pdev, iface->bar);
 513         pci_dev_put(iface->pdev);
 514  errout_free:
 515         kfree(iface);
 516         return rc;
 517 }
 518
 519 static int __init scx200_create_isa(const char *text, unsigned long base,
 520                 int index)
 521 {
 522         struct scx200_acb_iface *iface;
 523         int rc;
 524
 525         iface = scx200_create_iface(text, NULL, index);
 526
 527         if (iface == NULL)
 528                 return -ENOMEM;
 529
 530         if (!request_region(base, 8, iface->adapter.name)) {
 531                 printk(KERN_ERR NAME ": can't allocate io 0x%lx-0x%lx\n",
 532                        base, base + 8 - 1);
 533                 rc = -EBUSY;
 534                 goto errout_free;
 535         }
 536
 537         iface->base = base;
 538         rc = scx200_acb_create(iface);
 539
 540         if (rc == 0)
 541                 return 0;
 542
 543         release_region(base, 8);
 544  errout_free:
 545         kfree(iface);
 546         return rc;
 547 }
 548
 549 /* Driver data is an index into the scx200_data array that indicates
 550  * the name and the BAR where the I/O address resource is located.  ISA
 551  * devices are flagged with a bar value of -1 */
 552
 553 static struct pci_device_id scx200_pci[] = {
 554         { PCI_DEVICE(PCI_VENDOR_ID_NS, PCI_DEVICE_ID_NS_SCx200_BRIDGE),
 555           .driver_data = 0 },
 556         { PCI_DEVICE(PCI_VENDOR_ID_NS, PCI_DEVICE_ID_NS_SC1100_BRIDGE),
 557           .driver_data = 0 },
 558         { PCI_DEVICE(PCI_VENDOR_ID_NS, PCI_DEVICE_ID_NS_CS5535_ISA),
 559           .driver_data = 1 },
 560         { PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_CS5536_ISA),
 561           .driver_data = 2 }
 562 };
 563
 564 static struct {
 565         const char *name;
 566         int bar;
 567 } scx200_data[] = {
 568         { "SCx200", -1 },
 569         { "CS5535",  0 },
 570         { "CS5536",  0 }
 571 };
 572
 573 static __init int scx200_scan_pci(void)
 574 {
 575         int data, dev;
 576         int rc = -ENODEV;
 577         struct pci_dev *pdev;
 578
 579         for(dev = 0; dev < ARRAY_SIZE(scx200_pci); dev++) {
 580                 pdev = pci_get_device(scx200_pci[dev].vendor,
 581                                 scx200_pci[dev].device, NULL);
 582
 583                 if (pdev == NULL)
 584                         continue;
 585
 586                 data = scx200_pci[dev].driver_data;
 587
 588                 /* if .bar is greater or equal to zero, this is a
 589                  * PCI device - otherwise, we assume
 590                    that the ports are ISA based
 591                 */
 592
 593                 if (scx200_data[data].bar >= 0)
 594                         rc = scx200_create_pci(scx200_data[data].name, pdev,
 595                                         scx200_data[data].bar);
 596                 else {
 597                         int i;
 598
 599                         pci_dev_put(pdev);
 600                         for (i = 0; i < MAX_DEVICES; ++i) {
 601                                 if (base[i] == 0)
 602                                         continue;
 603
 604                                 rc = scx200_create_isa(scx200_data[data].name,
 605                                                 base[i],
 606                                                 i);
 607                         }
 608                 }
 609
 610                 break;
 611         }
 612
 613         return rc;
 614 }
 615
 616 static int __init scx200_acb_init(void)
 617 {
 618         int rc;
 619
 620         pr_debug(NAME ": NatSemi SCx200 ACCESS.bus Driver\n");
 621
 622         rc = scx200_scan_pci();
 623
 624         /* If at least one bus was created, init must succeed */
 625         if (scx200_acb_list)
 626                 return 0;
 627         return rc;
 628 }
 629
 630 static void __exit scx200_acb_cleanup(void)
 631 {
 632         struct scx200_acb_iface *iface;
 633
 634         mutex_lock(&scx200_acb_list_mutex);
 635         while ((iface = scx200_acb_list) != NULL) {
 636                 scx200_acb_list = iface->next;
 637                 mutex_unlock(&scx200_acb_list_mutex);
 638
 639                 i2c_del_adapter(&iface->adapter);
 640
 641                 if (iface->pdev) {
 642                         pci_release_region(iface->pdev, iface->bar);
 643                         pci_dev_put(iface->pdev);
 644                 }
 645                 else
 646                         release_region(iface->base, 8);
 647
 648                 kfree(iface);
 649                 mutex_lock(&scx200_acb_list_mutex);
 650         }
 651         mutex_unlock(&scx200_acb_list_mutex);
 652 }
 653
 654 module_init(scx200_acb_init);
 655 module_exit(scx200_acb_cleanup);