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