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 #include <asm/msr.h>
  37
  38 #include <linux/scx200.h>
  39
  40 #define NAME "scx200_acb"
  41
  42 MODULE_AUTHOR("Christer Weinigel <wingel@nano-system.com>");
  43 MODULE_DESCRIPTION("NatSemi SCx200 ACCESS.bus Driver");
  44 MODULE_LICENSE("GPL");
  45
  46 #define MAX_DEVICES 4
  47 static int base[MAX_DEVICES] = { 0x820, 0x840 };
  48 module_param_array(base, int, NULL, 0);
  49 MODULE_PARM_DESC(base, "Base addresses for the ACCESS.bus controllers");
  50
  51 #define POLL_TIMEOUT    (HZ/5)
  52
  53 enum scx200_acb_state {
  54         state_idle,
  55         state_address,
  56         state_command,
  57         state_repeat_start,
  58         state_quick,
  59         state_read,
  60         state_write,
  61 };
  62
  63 static const char *scx200_acb_state_name[] = {
  64         "idle",
  65         "address",
  66         "command",
  67         "repeat_start",
  68         "quick",
  69         "read",
  70         "write",
  71 };
  72
  73 /* Physical interface */
  74 struct scx200_acb_iface {
  75         struct scx200_acb_iface *next;
  76         struct i2c_adapter adapter;
  77         unsigned base;
  78         struct mutex mutex;
  79
  80         /* State machine data */
  81         enum scx200_acb_state state;
  82         int result;
  83         u8 address_byte;
  84         u8 command;
  85         u8 *ptr;
  86         char needs_reset;
  87         unsigned len;
  88 };
  89
  90 /* Register Definitions */
  91 #define ACBSDA          (iface->base + 0)
  92 #define ACBST           (iface->base + 1)
  93 #define    ACBST_SDAST          0x40 /* SDA Status */
  94 #define    ACBST_BER            0x20
  95 #define    ACBST_NEGACK         0x10 /* Negative Acknowledge */
  96 #define    ACBST_STASTR         0x08 /* Stall After Start */
  97 #define    ACBST_MASTER         0x02
  98 #define ACBCST          (iface->base + 2)
  99 #define    ACBCST_BB            0x02
 100 #define ACBCTL1         (iface->base + 3)
 101 #define    ACBCTL1_STASTRE      0x80
 102 #define    ACBCTL1_NMINTE       0x40
 103 #define    ACBCTL1_ACK          0x10
 104 #define    ACBCTL1_STOP         0x02
 105 #define    ACBCTL1_START        0x01
 106 #define ACBADDR         (iface->base + 4)
 107 #define ACBCTL2         (iface->base + 5)
 108 #define    ACBCTL2_ENABLE       0x01
 109
 110 /************************************************************************/
 111
 112 static void scx200_acb_machine(struct scx200_acb_iface *iface, u8 status)
 113 {
 114         const char *errmsg;
 115
 116         dev_dbg(&iface->adapter.dev, "state %s, status = 0x%02x\n",
 117                 scx200_acb_state_name[iface->state], status);
 118
 119         if (status & ACBST_BER) {
 120                 errmsg = "bus error";
 121                 goto error;
 122         }
 123         if (!(status & ACBST_MASTER)) {
 124                 errmsg = "not master";
 125                 goto error;
 126         }
 127         if (status & ACBST_NEGACK) {
 128                 dev_dbg(&iface->adapter.dev, "negative ack in state %s\n",
 129                         scx200_acb_state_name[iface->state]);
 130
 131                 iface->state = state_idle;
 132                 iface->result = -ENXIO;
 133
 134                 outb(inb(ACBCTL1) | ACBCTL1_STOP, ACBCTL1);
 135                 outb(ACBST_STASTR | ACBST_NEGACK, ACBST);
 136
 137                 /* Reset the status register */
 138                 outb(0, ACBST);
 139                 return;
 140         }
 141
 142         switch (iface->state) {
 143         case state_idle:
 144                 dev_warn(&iface->adapter.dev, "interrupt in idle state\n");
 145                 break;
 146
 147         case state_address:
 148                 /* Do a pointer write first */
 149                 outb(iface->address_byte & ~1, ACBSDA);
 150
 151                 iface->state = state_command;
 152                 break;
 153
 154         case state_command:
 155                 outb(iface->command, ACBSDA);
 156
 157                 if (iface->address_byte & 1)
 158                         iface->state = state_repeat_start;
 159                 else
 160                         iface->state = state_write;
 161                 break;
 162
 163         case state_repeat_start:
 164                 outb(inb(ACBCTL1) | ACBCTL1_START, ACBCTL1);
 165                 /* fallthrough */
 166
 167         case state_quick:
 168                 if (iface->address_byte & 1) {
 169                         if (iface->len == 1)
 170                                 outb(inb(ACBCTL1) | ACBCTL1_ACK, ACBCTL1);
 171                         else
 172                                 outb(inb(ACBCTL1) & ~ACBCTL1_ACK, ACBCTL1);
 173                         outb(iface->address_byte, ACBSDA);
 174
 175                         iface->state = state_read;
 176                 } else {
 177                         outb(iface->address_byte, ACBSDA);
 178
 179                         iface->state = state_write;
 180                 }
 181                 break;
 182
 183         case state_read:
 184                 /* Set ACK if receiving the last byte */
 185                 if (iface->len == 1)
 186                         outb(inb(ACBCTL1) | ACBCTL1_ACK, ACBCTL1);
 187                 else
 188                         outb(inb(ACBCTL1) & ~ACBCTL1_ACK, ACBCTL1);
 189
 190                 *iface->ptr++ = inb(ACBSDA);
 191                 --iface->len;
 192
 193                 if (iface->len == 0) {
 194                         iface->result = 0;
 195                         iface->state = state_idle;
 196                         outb(inb(ACBCTL1) | ACBCTL1_STOP, ACBCTL1);
 197                 }
 198
 199                 break;
 200
 201         case state_write:
 202                 if (iface->len == 0) {
 203                         iface->result = 0;
 204                         iface->state = state_idle;
 205                         outb(inb(ACBCTL1) | ACBCTL1_STOP, ACBCTL1);
 206                         break;
 207                 }
 208
 209                 outb(*iface->ptr++, ACBSDA);
 210                 --iface->len;
 211
 212                 break;
 213         }
 214
 215         return;
 216
 217  error:
 218         dev_err(&iface->adapter.dev, "%s in state %s\n", errmsg,
 219                 scx200_acb_state_name[iface->state]);
 220
 221         iface->state = state_idle;
 222         iface->result = -EIO;
 223         iface->needs_reset = 1;
 224 }
 225
 226 static void scx200_acb_poll(struct scx200_acb_iface *iface)
 227 {
 228         u8 status;
 229         unsigned long timeout;
 230
 231         timeout = jiffies + POLL_TIMEOUT;
 232         while (time_before(jiffies, timeout)) {
 233                 status = inb(ACBST);
 234
 235                 /* Reset the status register to avoid the hang */
 236                 outb(0, ACBST);
 237
 238                 if ((status & (ACBST_SDAST|ACBST_BER|ACBST_NEGACK)) != 0) {
 239                         scx200_acb_machine(iface, status);
 240                         return;
 241                 }
 242                 yield();
 243         }
 244
 245         dev_err(&iface->adapter.dev, "timeout in state %s\n",
 246                 scx200_acb_state_name[iface->state]);
 247
 248         iface->state = state_idle;
 249         iface->result = -EIO;
 250         iface->needs_reset = 1;
 251 }
 252
 253 static void scx200_acb_reset(struct scx200_acb_iface *iface)
 254 {
 255         /* Disable the ACCESS.bus device and Configure the SCL
 256            frequency: 16 clock cycles */
 257         outb(0x70, ACBCTL2);
 258         /* Polling mode */
 259         outb(0, ACBCTL1);
 260         /* Disable slave address */
 261         outb(0, ACBADDR);
 262         /* Enable the ACCESS.bus device */
 263         outb(inb(ACBCTL2) | ACBCTL2_ENABLE, ACBCTL2);
 264         /* Free STALL after START */
 265         outb(inb(ACBCTL1) & ~(ACBCTL1_STASTRE | ACBCTL1_NMINTE), ACBCTL1);
 266         /* Send a STOP */
 267         outb(inb(ACBCTL1) | ACBCTL1_STOP, ACBCTL1);
 268         /* Clear BER, NEGACK and STASTR bits */
 269         outb(ACBST_BER | ACBST_NEGACK | ACBST_STASTR, ACBST);
 270         /* Clear BB bit */
 271         outb(inb(ACBCST) | ACBCST_BB, ACBCST);
 272 }
 273
 274 static s32 scx200_acb_smbus_xfer(struct i2c_adapter *adapter,
 275                                  u16 address, unsigned short flags,
 276                                  char rw, u8 command, int size,
 277                                  union i2c_smbus_data *data)
 278 {
 279         struct scx200_acb_iface *iface = i2c_get_adapdata(adapter);
 280         int len;
 281         u8 *buffer;
 282         u16 cur_word;
 283         int rc;
 284
 285         switch (size) {
 286         case I2C_SMBUS_QUICK:
 287                 len = 0;
 288                 buffer = NULL;
 289                 break;
 290
 291         case I2C_SMBUS_BYTE:
 292                 len = 1;
 293                 buffer = rw ? &data->byte : &command;
 294                 break;
 295
 296         case I2C_SMBUS_BYTE_DATA:
 297                 len = 1;
 298                 buffer = &data->byte;
 299                 break;
 300
 301         case I2C_SMBUS_WORD_DATA:
 302                 len = 2;
 303                 cur_word = cpu_to_le16(data->word);
 304                 buffer = (u8 *)&cur_word;
 305                 break;
 306
 307         case I2C_SMBUS_BLOCK_DATA:
 308                 len = data->block[0];
 309                 buffer = &data->block[1];
 310                 break;
 311
 312         default:
 313                 return -EINVAL;
 314         }
 315
 316         dev_dbg(&adapter->dev,
 317                 "size=%d, address=0x%x, command=0x%x, len=%d, read=%d\n",
 318                 size, address, command, len, rw);
 319
 320         if (!len && rw == I2C_SMBUS_READ) {
 321                 dev_dbg(&adapter->dev, "zero length read\n");
 322                 return -EINVAL;
 323         }
 324
 325         mutex_lock(&iface->mutex);
 326
 327         iface->address_byte = (address << 1) | rw;
 328         iface->command = command;
 329         iface->ptr = buffer;
 330         iface->len = len;
 331         iface->result = -EINVAL;
 332         iface->needs_reset = 0;
 333
 334         outb(inb(ACBCTL1) | ACBCTL1_START, ACBCTL1);
 335
 336         if (size == I2C_SMBUS_QUICK || size == I2C_SMBUS_BYTE)
 337                 iface->state = state_quick;
 338         else
 339                 iface->state = state_address;
 340
 341         while (iface->state != state_idle)
 342                 scx200_acb_poll(iface);
 343
 344         if (iface->needs_reset)
 345                 scx200_acb_reset(iface);
 346
 347         rc = iface->result;
 348
 349         mutex_unlock(&iface->mutex);
 350
 351         if (rc == 0 && size == I2C_SMBUS_WORD_DATA && rw == I2C_SMBUS_READ)
 352                 data->word = le16_to_cpu(cur_word);
 353
 354 #ifdef DEBUG
 355         dev_dbg(&adapter->dev, "transfer done, result: %d", rc);
 356         if (buffer) {
 357                 int i;
 358                 printk(" data:");
 359                 for (i = 0; i < len; ++i)
 360                         printk(" %02x", buffer[i]);
 361         }
 362         printk("\n");
 363 #endif
 364
 365         return rc;
 366 }
 367
 368 static u32 scx200_acb_func(struct i2c_adapter *adapter)
 369 {
 370         return I2C_FUNC_SMBUS_QUICK | I2C_FUNC_SMBUS_BYTE |
 371                I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA |
 372                I2C_FUNC_SMBUS_BLOCK_DATA;
 373 }
 374
 375 /* For now, we only handle combined mode (smbus) */
 376 static struct i2c_algorithm scx200_acb_algorithm = {
 377         .smbus_xfer     = scx200_acb_smbus_xfer,
 378         .functionality  = scx200_acb_func,
 379 };
 380
 381 static struct scx200_acb_iface *scx200_acb_list;
 382 static DECLARE_MUTEX(scx200_acb_list_mutex);
 383
 384 static int scx200_acb_probe(struct scx200_acb_iface *iface)
 385 {
 386         u8 val;
 387
 388         /* Disable the ACCESS.bus device and Configure the SCL
 389            frequency: 16 clock cycles */
 390         outb(0x70, ACBCTL2);
 391
 392         if (inb(ACBCTL2) != 0x70) {
 393                 pr_debug(NAME ": ACBCTL2 readback failed\n");
 394                 return -ENXIO;
 395         }
 396
 397         outb(inb(ACBCTL1) | ACBCTL1_NMINTE, ACBCTL1);
 398
 399         val = inb(ACBCTL1);
 400         if (val) {
 401                 pr_debug(NAME ": disabled, but ACBCTL1=0x%02x\n",
 402                         val);
 403                 return -ENXIO;
 404         }
 405
 406         outb(inb(ACBCTL2) | ACBCTL2_ENABLE, ACBCTL2);
 407
 408         outb(inb(ACBCTL1) | ACBCTL1_NMINTE, ACBCTL1);
 409
 410         val = inb(ACBCTL1);
 411         if ((val & ACBCTL1_NMINTE) != ACBCTL1_NMINTE) {
 412                 pr_debug(NAME ": enabled, but NMINTE won't be set, "
 413                          "ACBCTL1=0x%02x\n", val);
 414                 return -ENXIO;
 415         }
 416
 417         return 0;
 418 }
 419
 420 static int  __init scx200_acb_create(const char *text, int base, int index)
 421 {
 422         struct scx200_acb_iface *iface;
 423         struct i2c_adapter *adapter;
 424         int rc;
 425
 426         iface = kzalloc(sizeof(*iface), GFP_KERNEL);
 427         if (!iface) {
 428                 printk(KERN_ERR NAME ": can't allocate memory\n");
 429                 rc = -ENOMEM;
 430                 goto errout;
 431         }
 432
 433         adapter = &iface->adapter;
 434         i2c_set_adapdata(adapter, iface);
 435         snprintf(adapter->name, I2C_NAME_SIZE, "%s ACB%d", text, index);
 436         adapter->owner = THIS_MODULE;
 437         adapter->id = I2C_HW_SMBUS_SCX200;
 438         adapter->algo = &scx200_acb_algorithm;
 439         adapter->class = I2C_CLASS_HWMON;
 440
 441         mutex_init(&iface->mutex);
 442
 443         if (!request_region(base, 8, adapter->name)) {
 444                 printk(KERN_ERR NAME ": can't allocate io 0x%x-0x%x\n",
 445                         base, base + 8-1);
 446                 rc = -EBUSY;
 447                 goto errout_free;
 448         }
 449         iface->base = base;
 450
 451         rc = scx200_acb_probe(iface);
 452         if (rc) {
 453                 printk(KERN_WARNING NAME ": probe failed\n");
 454                 goto errout_release;
 455         }
 456
 457         scx200_acb_reset(iface);
 458
 459         if (i2c_add_adapter(adapter) < 0) {
 460                 printk(KERN_ERR NAME ": failed to register\n");
 461                 rc = -ENODEV;
 462                 goto errout_release;
 463         }
 464
 465         down(&scx200_acb_list_mutex);
 466         iface->next = scx200_acb_list;
 467         scx200_acb_list = iface;
 468         up(&scx200_acb_list_mutex);
 469
 470         return 0;
 471
 472  errout_release:
 473         release_region(iface->base, 8);
 474  errout_free:
 475         kfree(iface);
 476  errout:
 477         return rc;
 478 }
 479
 480 static struct pci_device_id scx200[] = {
 481         { PCI_DEVICE(PCI_VENDOR_ID_NS, PCI_DEVICE_ID_NS_SCx200_BRIDGE) },
 482         { PCI_DEVICE(PCI_VENDOR_ID_NS, PCI_DEVICE_ID_NS_SC1100_BRIDGE) },
 483         { },
 484 };
 485
 486 static struct pci_device_id divil_pci[] = {
 487         { PCI_DEVICE(PCI_VENDOR_ID_NS,  PCI_DEVICE_ID_NS_CS5535_ISA) },
 488         { PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_CS5536_ISA) },
 489         { } /* NULL entry */
 490 };
 491
 492 #define MSR_LBAR_SMB            0x5140000B
 493
 494 static __init int scx200_add_cs553x(void)
 495 {
 496         u32     low, hi;
 497         u32     smb_base;
 498
 499         /* Grab & reserve the SMB I/O range */
 500         rdmsr(MSR_LBAR_SMB, low, hi);
 501
 502         /* Check the IO mask and whether SMB is enabled */
 503         if (hi != 0x0000F001) {
 504                 printk(KERN_WARNING NAME ": SMBus not enabled\n");
 505                 return -ENODEV;
 506         }
 507
 508         /* SMBus IO size is 8 bytes */
 509         smb_base = low & 0x0000FFF8;
 510
 511         return scx200_acb_create("CS5535", smb_base, 0);
 512 }
 513
 514 static int __init scx200_acb_init(void)
 515 {
 516         int i;
 517         int     rc = -ENODEV;
 518
 519         pr_debug(NAME ": NatSemi SCx200 ACCESS.bus Driver\n");
 520
 521         /* Verify that this really is a SCx200 processor */
 522         if (pci_dev_present(scx200)) {
 523                 for (i = 0; i < MAX_DEVICES; ++i) {
 524                         if (base[i] > 0)
 525                                 rc = scx200_acb_create("SCx200", base[i], i);
 526                 }
 527         } else if (pci_dev_present(divil_pci))
 528                 rc = scx200_add_cs553x();
 529
 530         /* If at least one bus was created, init must succeed */
 531         if (scx200_acb_list)
 532                 return 0;
 533         return rc;
 534 }
 535
 536 static void __exit scx200_acb_cleanup(void)
 537 {
 538         struct scx200_acb_iface *iface;
 539
 540         down(&scx200_acb_list_mutex);
 541         while ((iface = scx200_acb_list) != NULL) {
 542                 scx200_acb_list = iface->next;
 543                 up(&scx200_acb_list_mutex);
 544
 545                 i2c_del_adapter(&iface->adapter);
 546                 release_region(iface->base, 8);
 547                 kfree(iface);
 548                 down(&scx200_acb_list_mutex);
 549         }
 550         up(&scx200_acb_list_mutex);
 551 }
 552
 553 module_init(scx200_acb_init);
 554 module_exit(scx200_acb_cleanup);