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