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
   6     Based on i2c-keywest.c which is:
   7         Copyright (c) 2001 Benjamin Herrenschmidt <benh@kernel.crashing.org>
   8         Copyright (c) 2000 Philip Edelbrock <phil@stimpy.netroedge.com>
   9
  10     This program is free software; you can redistribute it and/or
  11     modify it under the terms of the GNU General Public License as
  12     published by the Free Software Foundation; either version 2 of the
  13     License, or (at your option) any later version.
  14
  15     This program is distributed in the hope that it will be useful,
  16     but WITHOUT ANY WARRANTY; without even the implied warranty of
  17     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  18     General Public License for more details.
  19
  20     You should have received a copy of the GNU General Public License
  21     along with this program; if not, write to the Free Software
  22     Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  23 */
  24
  25 #include <linux/module.h>
  26 #include <linux/errno.h>
  27 #include <linux/kernel.h>
  28 #include <linux/init.h>
  29 #include <linux/i2c.h>
  30 #include <linux/smp_lock.h>
  31 #include <linux/pci.h>
  32 #include <linux/delay.h>
  33 #include <asm/io.h>
  34
  35 #include <linux/scx200.h>
  36
  37 #define NAME "scx200_acb"
  38
  39 MODULE_AUTHOR("Christer Weinigel <wingel@nano-system.com>");
  40 MODULE_DESCRIPTION("NatSemi SCx200 ACCESS.bus Driver");
  41 MODULE_LICENSE("GPL");
  42
  43 #define MAX_DEVICES 4
  44 static int base[MAX_DEVICES] = { 0x820, 0x840 };
  45 module_param_array(base, int, NULL, 0);
  46 MODULE_PARM_DESC(base, "Base addresses for the ACCESS.bus controllers");
  47
  48 /* The hardware supports interrupt driven mode too, but I haven't
  49    implemented that. */
  50 #define POLLED_MODE 1
  51 #define POLL_TIMEOUT (HZ)
  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 semaphore sem;
  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                 goto negack;
 129
 130         switch (iface->state) {
 131         case state_idle:
 132                 dev_warn(&iface->adapter.dev, "interrupt in idle state\n");
 133                 break;
 134
 135         case state_address:
 136                 /* Do a pointer write first */
 137                 outb(iface->address_byte & ~1, ACBSDA);
 138
 139                 iface->state = state_command;
 140                 break;
 141
 142         case state_command:
 143                 outb(iface->command, ACBSDA);
 144
 145                 if (iface->address_byte & 1)
 146                         iface->state = state_repeat_start;
 147                 else
 148                         iface->state = state_write;
 149                 break;
 150
 151         case state_repeat_start:
 152                 outb(inb(ACBCTL1) | ACBCTL1_START, ACBCTL1);
 153                 /* fallthrough */
 154
 155         case state_quick:
 156                 if (iface->address_byte & 1) {
 157                         if (iface->len == 1)
 158                                 outb(inb(ACBCTL1) | ACBCTL1_ACK, ACBCTL1);
 159                         else
 160                                 outb(inb(ACBCTL1) & ~ACBCTL1_ACK, ACBCTL1);
 161                         outb(iface->address_byte, ACBSDA);
 162
 163                         iface->state = state_read;
 164                 } else {
 165                         outb(iface->address_byte, ACBSDA);
 166
 167                         iface->state = state_write;
 168                 }
 169                 break;
 170
 171         case state_read:
 172                 /* Set ACK if receiving the last byte */
 173                 if (iface->len == 1)
 174                         outb(inb(ACBCTL1) | ACBCTL1_ACK, ACBCTL1);
 175                 else
 176                         outb(inb(ACBCTL1) & ~ACBCTL1_ACK, ACBCTL1);
 177
 178                 *iface->ptr++ = inb(ACBSDA);
 179                 --iface->len;
 180
 181                 if (iface->len == 0) {
 182                         iface->result = 0;
 183                         iface->state = state_idle;
 184                         outb(inb(ACBCTL1) | ACBCTL1_STOP, ACBCTL1);
 185                 }
 186
 187                 break;
 188
 189         case state_write:
 190                 if (iface->len == 0) {
 191                         iface->result = 0;
 192                         iface->state = state_idle;
 193                         outb(inb(ACBCTL1) | ACBCTL1_STOP, ACBCTL1);
 194                         break;
 195                 }
 196
 197                 outb(*iface->ptr++, ACBSDA);
 198                 --iface->len;
 199
 200                 break;
 201         }
 202
 203         return;
 204
 205  negack:
 206         dev_dbg(&iface->adapter.dev, "negative ack in state %s\n",
 207                 scx200_acb_state_name[iface->state]);
 208
 209         iface->state = state_idle;
 210         iface->result = -ENXIO;
 211
 212         outb(inb(ACBCTL1) | ACBCTL1_STOP, ACBCTL1);
 213         outb(ACBST_STASTR | ACBST_NEGACK, ACBST);
 214         return;
 215
 216  error:
 217         dev_err(&iface->adapter.dev, "%s in state %s\n", errmsg,
 218                 scx200_acb_state_name[iface->state]);
 219
 220         iface->state = state_idle;
 221         iface->result = -EIO;
 222         iface->needs_reset = 1;
 223 }
 224
 225 static void scx200_acb_timeout(struct scx200_acb_iface *iface)
 226 {
 227         dev_err(&iface->adapter.dev, "timeout in state %s\n",
 228                 scx200_acb_state_name[iface->state]);
 229
 230         iface->state = state_idle;
 231         iface->result = -EIO;
 232         iface->needs_reset = 1;
 233 }
 234
 235 #ifdef POLLED_MODE
 236 static void scx200_acb_poll(struct scx200_acb_iface *iface)
 237 {
 238         u8 status = 0;
 239         unsigned long timeout;
 240
 241         timeout = jiffies + POLL_TIMEOUT;
 242         while (time_before(jiffies, timeout)) {
 243                 status = inb(ACBST);
 244                 if ((status & (ACBST_SDAST|ACBST_BER|ACBST_NEGACK)) != 0) {
 245                         scx200_acb_machine(iface, status);
 246                         return;
 247                 }
 248                 msleep(10);
 249         }
 250
 251         scx200_acb_timeout(iface);
 252 }
 253 #endif /* POLLED_MODE */
 254
 255 static void scx200_acb_reset(struct scx200_acb_iface *iface)
 256 {
 257         /* Disable the ACCESS.bus device and Configure the SCL
 258            frequency: 16 clock cycles */
 259         outb(0x70, ACBCTL2);
 260         /* Polling mode */
 261         outb(0, ACBCTL1);
 262         /* Disable slave address */
 263         outb(0, ACBADDR);
 264         /* Enable the ACCESS.bus device */
 265         outb(inb(ACBCTL2) | ACBCTL2_ENABLE, ACBCTL2);
 266         /* Free STALL after START */
 267         outb(inb(ACBCTL1) & ~(ACBCTL1_STASTRE | ACBCTL1_NMINTE), ACBCTL1);
 268         /* Send a STOP */
 269         outb(inb(ACBCTL1) | ACBCTL1_STOP, ACBCTL1);
 270         /* Clear BER, NEGACK and STASTR bits */
 271         outb(ACBST_BER | ACBST_NEGACK | ACBST_STASTR, ACBST);
 272         /* Clear BB bit */
 273         outb(inb(ACBCST) | ACBCST_BB, ACBCST);
 274 }
 275
 276 static s32 scx200_acb_smbus_xfer(struct i2c_adapter *adapter,
 277                                  u16 address, unsigned short flags,
 278                                  char rw, u8 command, int size,
 279                                  union i2c_smbus_data *data)
 280 {
 281         struct scx200_acb_iface *iface = i2c_get_adapdata(adapter);
 282         int len;
 283         u8 *buffer;
 284         u16 cur_word;
 285         int rc;
 286
 287         switch (size) {
 288         case I2C_SMBUS_QUICK:
 289                 len = 0;
 290                 buffer = NULL;
 291                 break;
 292
 293         case I2C_SMBUS_BYTE:
 294                 if (rw == I2C_SMBUS_READ) {
 295                         len = 1;
 296                         buffer = &data->byte;
 297                 } else {
 298                         len = 1;
 299                         buffer = &command;
 300                 }
 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_BLOCK_DATA:
 315                 len = data->block[0];
 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         down(&iface->sem);
 333
 334         iface->address_byte = address<<1;
 335         if (rw == I2C_SMBUS_READ)
 336                 iface->address_byte |= 1;
 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 #ifdef POLLED_MODE
 351         while (iface->state != state_idle)
 352                 scx200_acb_poll(iface);
 353 #else /* POLLED_MODE */
 354 #error Interrupt driven mode not implemented
 355 #endif /* POLLED_MODE */
 356
 357         if (iface->needs_reset)
 358                 scx200_acb_reset(iface);
 359
 360         rc = iface->result;
 361
 362         up(&iface->sem);
 363
 364         if (rc == 0 && size == I2C_SMBUS_WORD_DATA && rw == I2C_SMBUS_READ)
 365                 data->word = le16_to_cpu(cur_word);
 366
 367 #ifdef DEBUG
 368         dev_dbg(&adapter->dev, "transfer done, result: %d", rc);
 369         if (buffer) {
 370                 int i;
 371                 printk(" data:");
 372                 for (i = 0; i < len; ++i)
 373                         printk(" %02x", buffer[i]);
 374         }
 375         printk("\n");
 376 #endif
 377
 378         return rc;
 379 }
 380
 381 static u32 scx200_acb_func(struct i2c_adapter *adapter)
 382 {
 383         return I2C_FUNC_SMBUS_QUICK | I2C_FUNC_SMBUS_BYTE |
 384                I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA |
 385                I2C_FUNC_SMBUS_BLOCK_DATA;
 386 }
 387
 388 /* For now, we only handle combined mode (smbus) */
 389 static struct i2c_algorithm scx200_acb_algorithm = {
 390         .smbus_xfer     = scx200_acb_smbus_xfer,
 391         .functionality  = scx200_acb_func,
 392 };
 393
 394 static struct scx200_acb_iface *scx200_acb_list;
 395
 396 static int scx200_acb_probe(struct scx200_acb_iface *iface)
 397 {
 398         u8 val;
 399
 400         /* Disable the ACCESS.bus device and Configure the SCL
 401            frequency: 16 clock cycles */
 402         outb(0x70, ACBCTL2);
 403
 404         if (inb(ACBCTL2) != 0x70) {
 405                 pr_debug(NAME ": ACBCTL2 readback failed\n");
 406                 return -ENXIO;
 407         }
 408
 409         outb(inb(ACBCTL1) | ACBCTL1_NMINTE, ACBCTL1);
 410
 411         val = inb(ACBCTL1);
 412         if (val) {
 413                 pr_debug(NAME ": disabled, but ACBCTL1=0x%02x\n",
 414                         val);
 415                 return -ENXIO;
 416         }
 417
 418         outb(inb(ACBCTL2) | ACBCTL2_ENABLE, ACBCTL2);
 419
 420         outb(inb(ACBCTL1) | ACBCTL1_NMINTE, ACBCTL1);
 421
 422         val = inb(ACBCTL1);
 423         if ((val & ACBCTL1_NMINTE) != ACBCTL1_NMINTE) {
 424                 pr_debug(NAME ": enabled, but NMINTE won't be set, "
 425                          "ACBCTL1=0x%02x\n", val);
 426                 return -ENXIO;
 427         }
 428
 429         return 0;
 430 }
 431
 432 static int  __init scx200_acb_create(int base, int index)
 433 {
 434         struct scx200_acb_iface *iface;
 435         struct i2c_adapter *adapter;
 436         int rc = 0;
 437         char description[64];
 438
 439         iface = kzalloc(sizeof(*iface), GFP_KERNEL);
 440         if (!iface) {
 441                 printk(KERN_ERR NAME ": can't allocate memory\n");
 442                 rc = -ENOMEM;
 443                 goto errout;
 444         }
 445
 446         adapter = &iface->adapter;
 447         i2c_set_adapdata(adapter, iface);
 448         snprintf(adapter->name, I2C_NAME_SIZE, "SCx200 ACB%d", index);
 449         adapter->owner = THIS_MODULE;
 450         adapter->id = I2C_HW_SMBUS_SCX200;
 451         adapter->algo = &scx200_acb_algorithm;
 452         adapter->class = I2C_CLASS_HWMON;
 453
 454         init_MUTEX(&iface->sem);
 455
 456         snprintf(description, sizeof(description),
 457                  "NatSemi SCx200 ACCESS.bus [%s]", adapter->name);
 458         if (request_region(base, 8, description) == 0) {
 459                 printk(KERN_ERR NAME ": can't allocate io 0x%x-0x%x\n",
 460                         base, base + 8-1);
 461                 rc = -EBUSY;
 462                 goto errout;
 463         }
 464         iface->base = base;
 465
 466         rc = scx200_acb_probe(iface);
 467         if (rc) {
 468                 printk(KERN_WARNING NAME ": probe failed\n");
 469                 goto errout;
 470         }
 471
 472         scx200_acb_reset(iface);
 473
 474         if (i2c_add_adapter(adapter) < 0) {
 475                 printk(KERN_ERR NAME ": failed to register\n");
 476                 rc = -ENODEV;
 477                 goto errout;
 478         }
 479
 480         lock_kernel();
 481         iface->next = scx200_acb_list;
 482         scx200_acb_list = iface;
 483         unlock_kernel();
 484
 485         return 0;
 486
 487  errout:
 488         if (iface) {
 489                 if (iface->base)
 490                         release_region(iface->base, 8);
 491                 kfree(iface);
 492         }
 493         return rc;
 494 }
 495
 496 static struct pci_device_id scx200[] = {
 497         { PCI_DEVICE(PCI_VENDOR_ID_NS, PCI_DEVICE_ID_NS_SCx200_BRIDGE) },
 498         { PCI_DEVICE(PCI_VENDOR_ID_NS, PCI_DEVICE_ID_NS_SC1100_BRIDGE) },
 499         { },
 500 };
 501
 502 static int __init scx200_acb_init(void)
 503 {
 504         int i;
 505         int rc;
 506
 507         pr_debug(NAME ": NatSemi SCx200 ACCESS.bus Driver\n");
 508
 509         /* Verify that this really is a SCx200 processor */
 510         if (pci_dev_present(scx200) == 0)
 511                 return -ENODEV;
 512
 513         rc = -ENXIO;
 514         for (i = 0; i < MAX_DEVICES; ++i) {
 515                 if (base[i] > 0)
 516                         rc = scx200_acb_create(base[i], i);
 517         }
 518         if (scx200_acb_list)
 519                 return 0;
 520         return rc;
 521 }
 522
 523 static void __exit scx200_acb_cleanup(void)
 524 {
 525         struct scx200_acb_iface *iface;
 526
 527         lock_kernel();
 528         while ((iface = scx200_acb_list) != NULL) {
 529                 scx200_acb_list = iface->next;
 530                 unlock_kernel();
 531
 532                 i2c_del_adapter(&iface->adapter);
 533                 release_region(iface->base, 8);
 534                 kfree(iface);
 535                 lock_kernel();
 536         }
 537         unlock_kernel();
 538 }
 539
 540 module_init(scx200_acb_init);
 541 module_exit(scx200_acb_cleanup);