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,
 221                 "%s in state %s (addr=0x%02x, len=%d, status=0x%02x)\n", errmsg,
 222                 scx200_acb_state_name[iface->state], iface->address_byte,
 223                 iface->len, status);
 224
 225         iface->state = state_idle;
 226         iface->result = -EIO;
 227         iface->needs_reset = 1;
 228 }
 229
 230 static void scx200_acb_poll(struct scx200_acb_iface *iface)
 231 {
 232         u8 status;
 233         unsigned long timeout;
 234
 235         timeout = jiffies + POLL_TIMEOUT;
 236         while (1) {
 237                 status = inb(ACBST);
 238
 239                 /* Reset the status register to avoid the hang */
 240                 outb(0, ACBST);
 241
 242                 if ((status & (ACBST_SDAST|ACBST_BER|ACBST_NEGACK)) != 0) {
 243                         scx200_acb_machine(iface, status);
 244                         return;
 245                 }
 246                 if (time_after(jiffies, timeout))
 247                         break;
 248                 cpu_relax();
 249                 cond_resched();
 250         }
 251
 252         dev_err(&iface->adapter.dev, "timeout in state %s\n",
 253                 scx200_acb_state_name[iface->state]);
 254
 255         iface->state = state_idle;
 256         iface->result = -EIO;
 257         iface->needs_reset = 1;
 258 }
 259
 260 static void scx200_acb_reset(struct scx200_acb_iface *iface)
 261 {
 262         /* Disable the ACCESS.bus device and Configure the SCL
 263            frequency: 16 clock cycles */
 264         outb(0x70, ACBCTL2);
 265         /* Polling mode */
 266         outb(0, ACBCTL1);
 267         /* Disable slave address */
 268         outb(0, ACBADDR);
 269         /* Enable the ACCESS.bus device */
 270         outb(inb(ACBCTL2) | ACBCTL2_ENABLE, ACBCTL2);
 271         /* Free STALL after START */
 272         outb(inb(ACBCTL1) & ~(ACBCTL1_STASTRE | ACBCTL1_NMINTE), ACBCTL1);
 273         /* Send a STOP */
 274         outb(inb(ACBCTL1) | ACBCTL1_STOP, ACBCTL1);
 275         /* Clear BER, NEGACK and STASTR bits */
 276         outb(ACBST_BER | ACBST_NEGACK | ACBST_STASTR, ACBST);
 277         /* Clear BB bit */
 278         outb(inb(ACBCST) | ACBCST_BB, ACBCST);
 279 }
 280
 281 static s32 scx200_acb_smbus_xfer(struct i2c_adapter *adapter,
 282                                  u16 address, unsigned short flags,
 283                                  char rw, u8 command, int size,
 284                                  union i2c_smbus_data *data)
 285 {
 286         struct scx200_acb_iface *iface = i2c_get_adapdata(adapter);
 287         int len;
 288         u8 *buffer;
 289         u16 cur_word;
 290         int rc;
 291
 292         switch (size) {
 293         case I2C_SMBUS_QUICK:
 294                 len = 0;
 295                 buffer = NULL;
 296                 break;
 297
 298         case I2C_SMBUS_BYTE:
 299                 len = 1;
 300                 buffer = rw ? &data->byte : &command;
 301                 break;
 302
 303         case I2C_SMBUS_BYTE_DATA:
 304                 len = 1;
 305                 buffer = &data->byte;
 306                 break;
 307
 308         case I2C_SMBUS_WORD_DATA:
 309                 len = 2;
 310                 cur_word = cpu_to_le16(data->word);
 311                 buffer = (u8 *)&cur_word;
 312                 break;
 313
 314         case I2C_SMBUS_I2C_BLOCK_DATA:
 315                 len = data->block[0];
 316                 if (len == 0 || len > I2C_SMBUS_BLOCK_MAX)
 317                         return -EINVAL;
 318                 buffer = &data->block[1];
 319                 break;
 320
 321         default:
 322                 return -EINVAL;
 323         }
 324
 325         dev_dbg(&adapter->dev,
 326                 "size=%d, address=0x%x, command=0x%x, len=%d, read=%d\n",
 327                 size, address, command, len, rw);
 328
 329         if (!len && rw == I2C_SMBUS_READ) {
 330                 dev_dbg(&adapter->dev, "zero length read\n");
 331                 return -EINVAL;
 332         }
 333
 334         mutex_lock(&iface->mutex);
 335
 336         iface->address_byte = (address << 1) | rw;
 337         iface->command = command;
 338         iface->ptr = buffer;
 339         iface->len = len;
 340         iface->result = -EINVAL;
 341         iface->needs_reset = 0;
 342
 343         outb(inb(ACBCTL1) | ACBCTL1_START, ACBCTL1);
 344
 345         if (size == I2C_SMBUS_QUICK || size == I2C_SMBUS_BYTE)
 346                 iface->state = state_quick;
 347         else
 348                 iface->state = state_address;
 349
 350         while (iface->state != state_idle)
 351                 scx200_acb_poll(iface);
 352
 353         if (iface->needs_reset)
 354                 scx200_acb_reset(iface);
 355
 356         rc = iface->result;
 357
 358         mutex_unlock(&iface->mutex);
 359
 360         if (rc == 0 && size == I2C_SMBUS_WORD_DATA && rw == I2C_SMBUS_READ)
 361                 data->word = le16_to_cpu(cur_word);
 362
 363 #ifdef DEBUG
 364         dev_dbg(&adapter->dev, "transfer done, result: %d", rc);
 365         if (buffer) {
 366                 int i;
 367                 printk(" data:");
 368                 for (i = 0; i < len; ++i)
 369                         printk(" %02x", buffer[i]);
 370         }
 371         printk("\n");
 372 #endif
 373
 374         return rc;
 375 }
 376
 377 static u32 scx200_acb_func(struct i2c_adapter *adapter)
 378 {
 379         return I2C_FUNC_SMBUS_QUICK | I2C_FUNC_SMBUS_BYTE |
 380                I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA |
 381                I2C_FUNC_SMBUS_I2C_BLOCK;
 382 }
 383
 384 /* For now, we only handle combined mode (smbus) */
 385 static const struct i2c_algorithm scx200_acb_algorithm = {
 386         .smbus_xfer     = scx200_acb_smbus_xfer,
 387         .functionality  = scx200_acb_func,
 388 };
 389
 390 static struct scx200_acb_iface *scx200_acb_list;
 391 static DEFINE_MUTEX(scx200_acb_list_mutex);
 392
 393 static __init int scx200_acb_probe(struct scx200_acb_iface *iface)
 394 {
 395         u8 val;
 396
 397         /* Disable the ACCESS.bus device and Configure the SCL
 398            frequency: 16 clock cycles */
 399         outb(0x70, ACBCTL2);
 400
 401         if (inb(ACBCTL2) != 0x70) {
 402                 pr_debug(NAME ": ACBCTL2 readback failed\n");
 403                 return -ENXIO;
 404         }
 405
 406         outb(inb(ACBCTL1) | ACBCTL1_NMINTE, ACBCTL1);
 407
 408         val = inb(ACBCTL1);
 409         if (val) {
 410                 pr_debug(NAME ": disabled, but ACBCTL1=0x%02x\n",
 411                         val);
 412                 return -ENXIO;
 413         }
 414
 415         outb(inb(ACBCTL2) | ACBCTL2_ENABLE, ACBCTL2);
 416
 417         outb(inb(ACBCTL1) | ACBCTL1_NMINTE, ACBCTL1);
 418
 419         val = inb(ACBCTL1);
 420         if ((val & ACBCTL1_NMINTE) != ACBCTL1_NMINTE) {
 421                 pr_debug(NAME ": enabled, but NMINTE won't be set, "
 422                          "ACBCTL1=0x%02x\n", val);
 423                 return -ENXIO;
 424         }
 425
 426         return 0;
 427 }
 428
 429 static __init struct scx200_acb_iface *scx200_create_iface(const char *text,
 430                 struct device *dev, int index)
 431 {
 432         struct scx200_acb_iface *iface;
 433         struct i2c_adapter *adapter;
 434
 435         iface = kzalloc(sizeof(*iface), GFP_KERNEL);
 436         if (!iface) {
 437                 printk(KERN_ERR NAME ": can't allocate memory\n");
 438                 return NULL;
 439         }
 440
 441         adapter = &iface->adapter;
 442         i2c_set_adapdata(adapter, iface);
 443         snprintf(adapter->name, sizeof(adapter->name), "%s ACB%d", text, index);
 444         adapter->owner = THIS_MODULE;
 445         adapter->algo = &scx200_acb_algorithm;
 446         adapter->class = I2C_CLASS_HWMON | I2C_CLASS_SPD;
 447         adapter->dev.parent = dev;
 448
 449         mutex_init(&iface->mutex);
 450
 451         return iface;
 452 }
 453
 454 static int __init scx200_acb_create(struct scx200_acb_iface *iface)
 455 {
 456         struct i2c_adapter *adapter;
 457         int rc;
 458
 459         adapter = &iface->adapter;
 460
 461         rc = scx200_acb_probe(iface);
 462         if (rc) {
 463                 printk(KERN_WARNING NAME ": probe failed\n");
 464                 return rc;
 465         }
 466
 467         scx200_acb_reset(iface);
 468
 469         if (i2c_add_adapter(adapter) < 0) {
 470                 printk(KERN_ERR NAME ": failed to register\n");
 471                 return -ENODEV;
 472         }
 473
 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         return 0;
 480 }
 481
 482 static __init int scx200_create_pci(const char *text, struct pci_dev *pdev,
 483                 int bar)
 484 {
 485         struct scx200_acb_iface *iface;
 486         int rc;
 487
 488         iface = scx200_create_iface(text, &pdev->dev, 0);
 489
 490         if (iface == NULL)
 491                 return -ENOMEM;
 492
 493         iface->pdev = pdev;
 494         iface->bar = bar;
 495
 496         rc = pci_enable_device_io(iface->pdev);
 497         if (rc)
 498                 goto errout_free;
 499
 500         rc = pci_request_region(iface->pdev, iface->bar, iface->adapter.name);
 501         if (rc) {
 502                 printk(KERN_ERR NAME ": can't allocate PCI BAR %d\n",
 503                                 iface->bar);
 504                 goto errout_free;
 505         }
 506
 507         iface->base = pci_resource_start(iface->pdev, iface->bar);
 508         rc = scx200_acb_create(iface);
 509
 510         if (rc == 0)
 511                 return 0;
 512
 513         pci_release_region(iface->pdev, iface->bar);
 514         pci_dev_put(iface->pdev);
 515  errout_free:
 516         kfree(iface);
 517         return rc;
 518 }
 519
 520 static int __init scx200_create_isa(const char *text, unsigned long base,
 521                 int index)
 522 {
 523         struct scx200_acb_iface *iface;
 524         int rc;
 525
 526         iface = scx200_create_iface(text, NULL, index);
 527
 528         if (iface == NULL)
 529                 return -ENOMEM;
 530
 531         if (!request_region(base, 8, iface->adapter.name)) {
 532                 printk(KERN_ERR NAME ": can't allocate io 0x%lx-0x%lx\n",
 533                        base, base + 8 - 1);
 534                 rc = -EBUSY;
 535                 goto errout_free;
 536         }
 537
 538         iface->base = base;
 539         rc = scx200_acb_create(iface);
 540
 541         if (rc == 0)
 542                 return 0;
 543
 544         release_region(base, 8);
 545  errout_free:
 546         kfree(iface);
 547         return rc;
 548 }
 549
 550 /* Driver data is an index into the scx200_data array that indicates
 551  * the name and the BAR where the I/O address resource is located.  ISA
 552  * devices are flagged with a bar value of -1 */
 553
 554 static struct pci_device_id scx200_pci[] = {
 555         { PCI_DEVICE(PCI_VENDOR_ID_NS, PCI_DEVICE_ID_NS_SCx200_BRIDGE),
 556           .driver_data = 0 },
 557         { PCI_DEVICE(PCI_VENDOR_ID_NS, PCI_DEVICE_ID_NS_SC1100_BRIDGE),
 558           .driver_data = 0 },
 559         { PCI_DEVICE(PCI_VENDOR_ID_NS, PCI_DEVICE_ID_NS_CS5535_ISA),
 560           .driver_data = 1 },
 561         { PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_CS5536_ISA),
 562           .driver_data = 2 }
 563 };
 564
 565 static struct {
 566         const char *name;
 567         int bar;
 568 } scx200_data[] = {
 569         { "SCx200", -1 },
 570         { "CS5535",  0 },
 571         { "CS5536",  0 }
 572 };
 573
 574 static __init int scx200_scan_pci(void)
 575 {
 576         int data, dev;
 577         int rc = -ENODEV;
 578         struct pci_dev *pdev;
 579
 580         for(dev = 0; dev < ARRAY_SIZE(scx200_pci); dev++) {
 581                 pdev = pci_get_device(scx200_pci[dev].vendor,
 582                                 scx200_pci[dev].device, NULL);
 583
 584                 if (pdev == NULL)
 585                         continue;
 586
 587                 data = scx200_pci[dev].driver_data;
 588
 589                 /* if .bar is greater or equal to zero, this is a
 590                  * PCI device - otherwise, we assume
 591                    that the ports are ISA based
 592                 */
 593
 594                 if (scx200_data[data].bar >= 0)
 595                         rc = scx200_create_pci(scx200_data[data].name, pdev,
 596                                         scx200_data[data].bar);
 597                 else {
 598                         int i;
 599
 600                         pci_dev_put(pdev);
 601                         for (i = 0; i < MAX_DEVICES; ++i) {
 602                                 if (base[i] == 0)
 603                                         continue;
 604
 605                                 rc = scx200_create_isa(scx200_data[data].name,
 606                                                 base[i],
 607                                                 i);
 608                         }
 609                 }
 610
 611                 break;
 612         }
 613
 614         return rc;
 615 }
 616
 617 static int __init scx200_acb_init(void)
 618 {
 619         int rc;
 620
 621         pr_debug(NAME ": NatSemi SCx200 ACCESS.bus Driver\n");
 622
 623         rc = scx200_scan_pci();
 624
 625         /* If at least one bus was created, init must succeed */
 626         if (scx200_acb_list)
 627                 return 0;
 628         return rc;
 629 }
 630
 631 static void __exit scx200_acb_cleanup(void)
 632 {
 633         struct scx200_acb_iface *iface;
 634
 635         mutex_lock(&scx200_acb_list_mutex);
 636         while ((iface = scx200_acb_list) != NULL) {
 637                 scx200_acb_list = iface->next;
 638                 mutex_unlock(&scx200_acb_list_mutex);
 639
 640                 i2c_del_adapter(&iface->adapter);
 641
 642                 if (iface->pdev) {
 643                         pci_release_region(iface->pdev, iface->bar);
 644                         pci_dev_put(iface->pdev);
 645                 }
 646                 else
 647                         release_region(iface->base, 8);
 648
 649                 kfree(iface);
 650                 mutex_lock(&scx200_acb_list_mutex);
 651         }
 652         mutex_unlock(&scx200_acb_list_mutex);
 653 }
 654
 655 module_init(scx200_acb_init);
 656 module_exit(scx200_acb_cleanup);