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/smp_lock.h>
  32 #include <linux/pci.h>
  33 #include <linux/delay.h>
  34 #include <linux/mutex.h>
  35 #include <asm/io.h>
  36
  37 #include <linux/scx200.h>
  38
  39 #define NAME "scx200_acb"
  40
  41 MODULE_AUTHOR("Christer Weinigel <wingel@nano-system.com>");
  42 MODULE_DESCRIPTION("NatSemi SCx200 ACCESS.bus Driver");
  43 MODULE_LICENSE("GPL");
  44
  45 #define MAX_DEVICES 4
  46 static int base[MAX_DEVICES] = { 0x820, 0x840 };
  47 module_param_array(base, int, NULL, 0);
  48 MODULE_PARM_DESC(base, "Base addresses for the ACCESS.bus controllers");
  49
  50 #define POLL_TIMEOUT    (HZ/5)
  51
  52 enum scx200_acb_state {
  53         state_idle,
  54         state_address,
  55         state_command,
  56         state_repeat_start,
  57         state_quick,
  58         state_read,
  59         state_write,
  60 };
  61
  62 static const char *scx200_acb_state_name[] = {
  63         "idle",
  64         "address",
  65         "command",
  66         "repeat_start",
  67         "quick",
  68         "read",
  69         "write",
  70 };
  71
  72 /* Physical interface */
  73 struct scx200_acb_iface {
  74         struct scx200_acb_iface *next;
  75         struct i2c_adapter adapter;
  76         unsigned base;
  77         struct mutex mutex;
  78
  79         /* State machine data */
  80         enum scx200_acb_state state;
  81         int result;
  82         u8 address_byte;
  83         u8 command;
  84         u8 *ptr;
  85         char needs_reset;
  86         unsigned len;
  87
  88         /* PCI device info */
  89         struct pci_dev *pdev;
  90         int bar;
  91 };
  92
  93 /* Register Definitions */
  94 #define ACBSDA          (iface->base + 0)
  95 #define ACBST           (iface->base + 1)
  96 #define    ACBST_SDAST          0x40 /* SDA Status */
  97 #define    ACBST_BER            0x20
  98 #define    ACBST_NEGACK         0x10 /* Negative Acknowledge */
  99 #define    ACBST_STASTR         0x08 /* Stall After Start */
 100 #define    ACBST_MASTER         0x02
 101 #define ACBCST          (iface->base + 2)
 102 #define    ACBCST_BB            0x02
 103 #define ACBCTL1         (iface->base + 3)
 104 #define    ACBCTL1_STASTRE      0x80
 105 #define    ACBCTL1_NMINTE       0x40
 106 #define    ACBCTL1_ACK          0x10
 107 #define    ACBCTL1_STOP         0x02
 108 #define    ACBCTL1_START        0x01
 109 #define ACBADDR         (iface->base + 4)
 110 #define ACBCTL2         (iface->base + 5)
 111 #define    ACBCTL2_ENABLE       0x01
 112
 113 /************************************************************************/
 114
 115 static void scx200_acb_machine(struct scx200_acb_iface *iface, u8 status)
 116 {
 117         const char *errmsg;
 118
 119         dev_dbg(&iface->adapter.dev, "state %s, status = 0x%02x\n",
 120                 scx200_acb_state_name[iface->state], status);
 121
 122         if (status & ACBST_BER) {
 123                 errmsg = "bus error";
 124                 goto error;
 125         }
 126         if (!(status & ACBST_MASTER)) {
 127                 errmsg = "not master";
 128                 goto error;
 129         }
 130         if (status & ACBST_NEGACK) {
 131                 dev_dbg(&iface->adapter.dev, "negative ack in state %s\n",
 132                         scx200_acb_state_name[iface->state]);
 133
 134                 iface->state = state_idle;
 135                 iface->result = -ENXIO;
 136
 137                 outb(inb(ACBCTL1) | ACBCTL1_STOP, ACBCTL1);
 138                 outb(ACBST_STASTR | ACBST_NEGACK, ACBST);
 139
 140                 /* Reset the status register */
 141                 outb(0, ACBST);
 142                 return;
 143         }
 144
 145         switch (iface->state) {
 146         case state_idle:
 147                 dev_warn(&iface->adapter.dev, "interrupt in idle state\n");
 148                 break;
 149
 150         case state_address:
 151                 /* Do a pointer write first */
 152                 outb(iface->address_byte & ~1, ACBSDA);
 153
 154                 iface->state = state_command;
 155                 break;
 156
 157         case state_command:
 158                 outb(iface->command, ACBSDA);
 159
 160                 if (iface->address_byte & 1)
 161                         iface->state = state_repeat_start;
 162                 else
 163                         iface->state = state_write;
 164                 break;
 165
 166         case state_repeat_start:
 167                 outb(inb(ACBCTL1) | ACBCTL1_START, ACBCTL1);
 168                 /* fallthrough */
 169
 170         case state_quick:
 171                 if (iface->address_byte & 1) {
 172                         if (iface->len == 1)
 173                                 outb(inb(ACBCTL1) | ACBCTL1_ACK, ACBCTL1);
 174                         else
 175                                 outb(inb(ACBCTL1) & ~ACBCTL1_ACK, ACBCTL1);
 176                         outb(iface->address_byte, ACBSDA);
 177
 178                         iface->state = state_read;
 179                 } else {
 180                         outb(iface->address_byte, ACBSDA);
 181
 182                         iface->state = state_write;
 183                 }
 184                 break;
 185
 186         case state_read:
 187                 /* Set ACK if receiving the last byte */
 188                 if (iface->len == 1)
 189                         outb(inb(ACBCTL1) | ACBCTL1_ACK, ACBCTL1);
 190                 else
 191                         outb(inb(ACBCTL1) & ~ACBCTL1_ACK, ACBCTL1);
 192
 193                 *iface->ptr++ = inb(ACBSDA);
 194                 --iface->len;
 195
 196                 if (iface->len == 0) {
 197                         iface->result = 0;
 198                         iface->state = state_idle;
 199                         outb(inb(ACBCTL1) | ACBCTL1_STOP, ACBCTL1);
 200                 }
 201
 202                 break;
 203
 204         case state_write:
 205                 if (iface->len == 0) {
 206                         iface->result = 0;
 207                         iface->state = state_idle;
 208                         outb(inb(ACBCTL1) | ACBCTL1_STOP, ACBCTL1);
 209                         break;
 210                 }
 211
 212                 outb(*iface->ptr++, ACBSDA);
 213                 --iface->len;
 214
 215                 break;
 216         }
 217
 218         return;
 219
 220  error:
 221         dev_err(&iface->adapter.dev, "%s in state %s\n", errmsg,
 222                 scx200_acb_state_name[iface->state]);
 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 (time_before(jiffies, timeout)) {
 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                 yield();
 246         }
 247
 248         dev_err(&iface->adapter.dev, "timeout in state %s\n",
 249                 scx200_acb_state_name[iface->state]);
 250
 251         iface->state = state_idle;
 252         iface->result = -EIO;
 253         iface->needs_reset = 1;
 254 }
 255
 256 static void scx200_acb_reset(struct scx200_acb_iface *iface)
 257 {
 258         /* Disable the ACCESS.bus device and Configure the SCL
 259            frequency: 16 clock cycles */
 260         outb(0x70, ACBCTL2);
 261         /* Polling mode */
 262         outb(0, ACBCTL1);
 263         /* Disable slave address */
 264         outb(0, ACBADDR);
 265         /* Enable the ACCESS.bus device */
 266         outb(inb(ACBCTL2) | ACBCTL2_ENABLE, ACBCTL2);
 267         /* Free STALL after START */
 268         outb(inb(ACBCTL1) & ~(ACBCTL1_STASTRE | ACBCTL1_NMINTE), ACBCTL1);
 269         /* Send a STOP */
 270         outb(inb(ACBCTL1) | ACBCTL1_STOP, ACBCTL1);
 271         /* Clear BER, NEGACK and STASTR bits */
 272         outb(ACBST_BER | ACBST_NEGACK | ACBST_STASTR, ACBST);
 273         /* Clear BB bit */
 274         outb(inb(ACBCST) | ACBCST_BB, ACBCST);
 275 }
 276
 277 static s32 scx200_acb_smbus_xfer(struct i2c_adapter *adapter,
 278                                  u16 address, unsigned short flags,
 279                                  char rw, u8 command, int size,
 280                                  union i2c_smbus_data *data)
 281 {
 282         struct scx200_acb_iface *iface = i2c_get_adapdata(adapter);
 283         int len;
 284         u8 *buffer;
 285         u16 cur_word;
 286         int rc;
 287
 288         switch (size) {
 289         case I2C_SMBUS_QUICK:
 290                 len = 0;
 291                 buffer = NULL;
 292                 break;
 293
 294         case I2C_SMBUS_BYTE:
 295                 len = 1;
 296                 buffer = rw ? &data->byte : &command;
 297                 break;
 298
 299         case I2C_SMBUS_BYTE_DATA:
 300                 len = 1;
 301                 buffer = &data->byte;
 302                 break;
 303
 304         case I2C_SMBUS_WORD_DATA:
 305                 len = 2;
 306                 cur_word = cpu_to_le16(data->word);
 307                 buffer = (u8 *)&cur_word;
 308                 break;
 309
 310         case I2C_SMBUS_BLOCK_DATA:
 311                 len = data->block[0];
 312                 buffer = &data->block[1];
 313                 break;
 314
 315         default:
 316                 return -EINVAL;
 317         }
 318
 319         dev_dbg(&adapter->dev,
 320                 "size=%d, address=0x%x, command=0x%x, len=%d, read=%d\n",
 321                 size, address, command, len, rw);
 322
 323         if (!len && rw == I2C_SMBUS_READ) {
 324                 dev_dbg(&adapter->dev, "zero length read\n");
 325                 return -EINVAL;
 326         }
 327
 328         mutex_lock(&iface->mutex);
 329
 330         iface->address_byte = (address << 1) | rw;
 331         iface->command = command;
 332         iface->ptr = buffer;
 333         iface->len = len;
 334         iface->result = -EINVAL;
 335         iface->needs_reset = 0;
 336
 337         outb(inb(ACBCTL1) | ACBCTL1_START, ACBCTL1);
 338
 339         if (size == I2C_SMBUS_QUICK || size == I2C_SMBUS_BYTE)
 340                 iface->state = state_quick;
 341         else
 342                 iface->state = state_address;
 343
 344         while (iface->state != state_idle)
 345                 scx200_acb_poll(iface);
 346
 347         if (iface->needs_reset)
 348                 scx200_acb_reset(iface);
 349
 350         rc = iface->result;
 351
 352         mutex_unlock(&iface->mutex);
 353
 354         if (rc == 0 && size == I2C_SMBUS_WORD_DATA && rw == I2C_SMBUS_READ)
 355                 data->word = le16_to_cpu(cur_word);
 356
 357 #ifdef DEBUG
 358         dev_dbg(&adapter->dev, "transfer done, result: %d", rc);
 359         if (buffer) {
 360                 int i;
 361                 printk(" data:");
 362                 for (i = 0; i < len; ++i)
 363                         printk(" %02x", buffer[i]);
 364         }
 365         printk("\n");
 366 #endif
 367
 368         return rc;
 369 }
 370
 371 static u32 scx200_acb_func(struct i2c_adapter *adapter)
 372 {
 373         return I2C_FUNC_SMBUS_QUICK | I2C_FUNC_SMBUS_BYTE |
 374                I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA |
 375                I2C_FUNC_SMBUS_BLOCK_DATA;
 376 }
 377
 378 /* For now, we only handle combined mode (smbus) */
 379 static struct i2c_algorithm scx200_acb_algorithm = {
 380         .smbus_xfer     = scx200_acb_smbus_xfer,
 381         .functionality  = scx200_acb_func,
 382 };
 383
 384 static struct scx200_acb_iface *scx200_acb_list;
 385 static DECLARE_MUTEX(scx200_acb_list_mutex);
 386
 387 static __init int scx200_acb_probe(struct scx200_acb_iface *iface)
 388 {
 389         u8 val;
 390
 391         /* Disable the ACCESS.bus device and Configure the SCL
 392            frequency: 16 clock cycles */
 393         outb(0x70, ACBCTL2);
 394
 395         if (inb(ACBCTL2) != 0x70) {
 396                 pr_debug(NAME ": ACBCTL2 readback failed\n");
 397                 return -ENXIO;
 398         }
 399
 400         outb(inb(ACBCTL1) | ACBCTL1_NMINTE, ACBCTL1);
 401
 402         val = inb(ACBCTL1);
 403         if (val) {
 404                 pr_debug(NAME ": disabled, but ACBCTL1=0x%02x\n",
 405                         val);
 406                 return -ENXIO;
 407         }
 408
 409         outb(inb(ACBCTL2) | ACBCTL2_ENABLE, ACBCTL2);
 410
 411         outb(inb(ACBCTL1) | ACBCTL1_NMINTE, ACBCTL1);
 412
 413         val = inb(ACBCTL1);
 414         if ((val & ACBCTL1_NMINTE) != ACBCTL1_NMINTE) {
 415                 pr_debug(NAME ": enabled, but NMINTE won't be set, "
 416                          "ACBCTL1=0x%02x\n", val);
 417                 return -ENXIO;
 418         }
 419
 420         return 0;
 421 }
 422
 423 static __init struct scx200_acb_iface *scx200_create_iface(const char *text,
 424                 int index)
 425 {
 426         struct scx200_acb_iface *iface;
 427         struct i2c_adapter *adapter;
 428
 429         iface = kzalloc(sizeof(*iface), GFP_KERNEL);
 430         if (!iface) {
 431                 printk(KERN_ERR NAME ": can't allocate memory\n");
 432                 return NULL;
 433         }
 434
 435         adapter = &iface->adapter;
 436         i2c_set_adapdata(adapter, iface);
 437         snprintf(adapter->name, I2C_NAME_SIZE, "%s ACB%d", text, index);
 438         adapter->owner = THIS_MODULE;
 439         adapter->id = I2C_HW_SMBUS_SCX200;
 440         adapter->algo = &scx200_acb_algorithm;
 441         adapter->class = I2C_CLASS_HWMON;
 442
 443         mutex_init(&iface->mutex);
 444
 445         return iface;
 446 }
 447
 448 static int __init scx200_acb_create(struct scx200_acb_iface *iface)
 449 {
 450         struct i2c_adapter *adapter;
 451         int rc;
 452
 453         adapter = &iface->adapter;
 454
 455         rc = scx200_acb_probe(iface);
 456         if (rc) {
 457                 printk(KERN_WARNING NAME ": probe failed\n");
 458                 return rc;
 459         }
 460
 461         scx200_acb_reset(iface);
 462
 463         if (i2c_add_adapter(adapter) < 0) {
 464                 printk(KERN_ERR NAME ": failed to register\n");
 465                 return -ENODEV;
 466         }
 467
 468         down(&scx200_acb_list_mutex);
 469         iface->next = scx200_acb_list;
 470         scx200_acb_list = iface;
 471         up(&scx200_acb_list_mutex);
 472
 473         return 0;
 474 }
 475
 476 static __init int scx200_create_pci(const char *text, struct pci_dev *pdev,
 477                 int bar)
 478 {
 479         struct scx200_acb_iface *iface;
 480         int rc;
 481
 482         iface = scx200_create_iface(text, 0);
 483
 484         if (iface == NULL)
 485                 return -ENOMEM;
 486
 487         iface->pdev = pdev;
 488         iface->bar = bar;
 489
 490         pci_enable_device_bars(iface->pdev, 1 << iface->bar);
 491
 492         rc = pci_request_region(iface->pdev, iface->bar, iface->adapter.name);
 493
 494         if (rc != 0) {
 495                 printk(KERN_ERR NAME ": can't allocate PCI BAR %d\n",
 496                                 iface->bar);
 497                 goto errout_free;
 498         }
 499
 500         iface->base = pci_resource_start(iface->pdev, iface->bar);
 501         rc = scx200_acb_create(iface);
 502
 503         if (rc == 0)
 504                 return 0;
 505
 506         pci_release_region(iface->pdev, iface->bar);
 507         pci_dev_put(iface->pdev);
 508  errout_free:
 509         kfree(iface);
 510         return rc;
 511 }
 512
 513 static int __init scx200_create_isa(const char *text, unsigned long base,
 514                 int index)
 515 {
 516         struct scx200_acb_iface *iface;
 517         int rc;
 518
 519         iface = scx200_create_iface(text, index);
 520
 521         if (iface == NULL)
 522                 return -ENOMEM;
 523
 524         if (request_region(base, 8, iface->adapter.name) == 0) {
 525                 printk(KERN_ERR NAME ": can't allocate io 0x%lx-0x%lx\n",
 526                        base, base + 8 - 1);
 527                 rc = -EBUSY;
 528                 goto errout_free;
 529         }
 530
 531         iface->base = base;
 532         rc = scx200_acb_create(iface);
 533
 534         if (rc == 0)
 535                 return 0;
 536
 537         release_region(base, 8);
 538  errout_free:
 539         kfree(iface);
 540         return rc;
 541 }
 542
 543 /* Driver data is an index into the scx200_data array that indicates
 544  * the name and the BAR where the I/O address resource is located.  ISA
 545  * devices are flagged with a bar value of -1 */
 546
 547 static struct pci_device_id scx200_pci[] = {
 548         { PCI_DEVICE(PCI_VENDOR_ID_NS, PCI_DEVICE_ID_NS_SCx200_BRIDGE),
 549           .driver_data = 0 },
 550         { PCI_DEVICE(PCI_VENDOR_ID_NS, PCI_DEVICE_ID_NS_SC1100_BRIDGE),
 551           .driver_data = 0 },
 552         { PCI_DEVICE(PCI_VENDOR_ID_NS, PCI_DEVICE_ID_NS_CS5535_ISA),
 553           .driver_data = 1 },
 554         { PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_CS5536_ISA),
 555           .driver_data = 2 }
 556 };
 557
 558 static struct {
 559         const char *name;
 560         int bar;
 561 } scx200_data[] = {
 562         { "SCx200", -1 },
 563         { "CS5535",  0 },
 564         { "CS5536",  0 }
 565 };
 566
 567 static __init int scx200_scan_pci(void)
 568 {
 569         int data, dev;
 570         int rc = -ENODEV;
 571         struct pci_dev *pdev;
 572
 573         for(dev = 0; dev < ARRAY_SIZE(scx200_pci); dev++) {
 574                 pdev = pci_get_device(scx200_pci[dev].vendor,
 575                                 scx200_pci[dev].device, NULL);
 576
 577                 if (pdev == NULL)
 578                         continue;
 579
 580                 data = scx200_pci[dev].driver_data;
 581
 582                 /* if .bar is greater or equal to zero, this is a
 583                  * PCI device - otherwise, we assume
 584                    that the ports are ISA based
 585                 */
 586
 587                 if (scx200_data[data].bar >= 0)
 588                         rc = scx200_create_pci(scx200_data[data].name, pdev,
 589                                         scx200_data[data].bar);
 590                 else {
 591                         int i;
 592
 593                         for (i = 0; i < MAX_DEVICES; ++i) {
 594                                 if (base[i] == 0)
 595                                         continue;
 596
 597                                 rc = scx200_create_isa(scx200_data[data].name,
 598                                                 base[i],
 599                                                 i);
 600                         }
 601                 }
 602
 603                 break;
 604         }
 605
 606         return rc;
 607 }
 608
 609 static int __init scx200_acb_init(void)
 610 {
 611         int rc;
 612
 613         pr_debug(NAME ": NatSemi SCx200 ACCESS.bus Driver\n");
 614
 615         rc = scx200_scan_pci();
 616
 617         /* If at least one bus was created, init must succeed */
 618         if (scx200_acb_list)
 619                 return 0;
 620         return rc;
 621 }
 622
 623 static void __exit scx200_acb_cleanup(void)
 624 {
 625         struct scx200_acb_iface *iface;
 626
 627         down(&scx200_acb_list_mutex);
 628         while ((iface = scx200_acb_list) != NULL) {
 629                 scx200_acb_list = iface->next;
 630                 up(&scx200_acb_list_mutex);
 631
 632                 i2c_del_adapter(&iface->adapter);
 633
 634                 if (iface->pdev) {
 635                         pci_release_region(iface->pdev, iface->bar);
 636                         pci_dev_put(iface->pdev);
 637                 }
 638                 else
 639                         release_region(iface->base, 8);
 640
 641                 kfree(iface);
 642                 down(&scx200_acb_list_mutex);
 643         }
 644         up(&scx200_acb_list_mutex);
 645 }
 646
 647 module_init(scx200_acb_init);
 648 module_exit(scx200_acb_cleanup);