drivers/i2c/busses/scx200_acb.c

   1 /*  linux/drivers/i2c/scx200_acb.c
   2
   3     Copyright (c) 2001,2002 Christer Weinigel <wingel@nano-system.com>
   4
   5     National Semiconductor SCx200 ACCESS.bus support
   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
  27 #include <linux/config.h>
  28 #include <linux/module.h>
  29 #include <linux/errno.h>
  30 #include <linux/kernel.h>
  31 #include <linux/init.h>
  32 #include <linux/i2c.h>
  33 #include <linux/smp_lock.h>
  34 #include <linux/pci.h>
  35 #include <linux/delay.h>
  36 #include <asm/io.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 static int num_base;
  49 module_param_array(base, int, num_base, 0);
  50 MODULE_PARM_DESC(base, "Base addresses for the ACCESS.bus controllers");
  51
  52 #ifdef DEBUG
  53 #define DBG(x...) printk(KERN_DEBUG NAME ": " x)
  54 #else
  55 #define DBG(x...)
  56 #endif
  57
  58 /* The hardware supports interrupt driven mode too, but I haven't
  59    implemented that. */
  60 #define POLLED_MODE 1
  61 #define POLL_TIMEOUT (HZ)
  62
  63 enum scx200_acb_state {
  64         state_idle,
  65         state_address,
  66         state_command,
  67         state_repeat_start,
  68         state_quick,
  69         state_read,
  70         state_write,
  71 };
  72
  73 static const char *scx200_acb_state_name[] = {
  74         "idle",
  75         "address",
  76         "command",
  77         "repeat_start",
  78         "quick",
  79         "read",
  80         "write",
  81 };
  82
  83 /* Physical interface */
  84 struct scx200_acb_iface
  85 {
  86         struct scx200_acb_iface *next;
  87         struct i2c_adapter adapter;
  88         unsigned base;
  89         struct semaphore sem;
  90
  91         /* State machine data */
  92         enum scx200_acb_state state;
  93         int result;
  94         u8 address_byte;
  95         u8 command;
  96         u8 *ptr;
  97         char needs_reset;
  98         unsigned len;
  99 };
 100
 101 /* Register Definitions */
 102 #define ACBSDA          (iface->base + 0)
 103 #define ACBST           (iface->base + 1)
 104 #define    ACBST_SDAST          0x40 /* SDA Status */
 105 #define    ACBST_BER            0x20
 106 #define    ACBST_NEGACK         0x10 /* Negative Acknowledge */
 107 #define    ACBST_STASTR         0x08 /* Stall After Start */
 108 #define    ACBST_MASTER         0x02
 109 #define ACBCST          (iface->base + 2)
 110 #define    ACBCST_BB            0x02
 111 #define ACBCTL1         (iface->base + 3)
 112 #define    ACBCTL1_STASTRE      0x80
 113 #define    ACBCTL1_NMINTE       0x40
 114 #define    ACBCTL1_ACK          0x10
 115 #define    ACBCTL1_STOP         0x02
 116 #define    ACBCTL1_START        0x01
 117 #define ACBADDR         (iface->base + 4)
 118 #define ACBCTL2         (iface->base + 5)
 119 #define    ACBCTL2_ENABLE       0x01
 120
 121 /************************************************************************/
 122
 123 static void scx200_acb_machine(struct scx200_acb_iface *iface, u8 status)
 124 {
 125         const char *errmsg;
 126
 127         DBG("state %s, status = 0x%02x\n",
 128             scx200_acb_state_name[iface->state], status);
 129
 130         if (status & ACBST_BER) {
 131                 errmsg = "bus error";
 132                 goto error;
 133         }
 134         if (!(status & ACBST_MASTER)) {
 135                 errmsg = "not master";
 136                 goto error;
 137         }
 138         if (status & ACBST_NEGACK)
 139                 goto negack;
 140
 141         switch (iface->state) {
 142         case state_idle:
 143                 dev_warn(&iface->adapter.dev, "interrupt in idle state\n");
 144                 break;
 145
 146         case state_address:
 147                 /* Do a pointer write first */
 148                 outb(iface->address_byte & ~1, ACBSDA);
 149
 150                 iface->state = state_command;
 151                 break;
 152
 153         case state_command:
 154                 outb(iface->command, ACBSDA);
 155
 156                 if (iface->address_byte & 1)
 157                         iface->state = state_repeat_start;
 158                 else
 159                         iface->state = state_write;
 160                 break;
 161
 162         case state_repeat_start:
 163                 outb(inb(ACBCTL1) | ACBCTL1_START, ACBCTL1);
 164                 /* fallthrough */
 165
 166         case state_quick:
 167                 if (iface->address_byte & 1) {
 168                         if (iface->len == 1)
 169                                 outb(inb(ACBCTL1) | ACBCTL1_ACK, ACBCTL1);
 170                         else
 171                                 outb(inb(ACBCTL1) & ~ACBCTL1_ACK, ACBCTL1);
 172                         outb(iface->address_byte, ACBSDA);
 173
 174                         iface->state = state_read;
 175                 } else {
 176                         outb(iface->address_byte, ACBSDA);
 177
 178                         iface->state = state_write;
 179                 }
 180                 break;
 181
 182         case state_read:
 183                 /* Set ACK if receiving the last byte */
 184                 if (iface->len == 1)
 185                         outb(inb(ACBCTL1) | ACBCTL1_ACK, ACBCTL1);
 186                 else
 187                         outb(inb(ACBCTL1) & ~ACBCTL1_ACK, ACBCTL1);
 188
 189                 *iface->ptr++ = inb(ACBSDA);
 190                 --iface->len;
 191
 192                 if (iface->len == 0) {
 193                         iface->result = 0;
 194                         iface->state = state_idle;
 195                         outb(inb(ACBCTL1) | ACBCTL1_STOP, ACBCTL1);
 196                 }
 197
 198                 break;
 199
 200         case state_write:
 201                 if (iface->len == 0) {
 202                         iface->result = 0;
 203                         iface->state = state_idle;
 204                         outb(inb(ACBCTL1) | ACBCTL1_STOP, ACBCTL1);
 205                         break;
 206                 }
 207
 208                 outb(*iface->ptr++, ACBSDA);
 209                 --iface->len;
 210
 211                 break;
 212         }
 213
 214         return;
 215
 216  negack:
 217         DBG("negative acknowledge in state %s\n",
 218             scx200_acb_state_name[iface->state]);
 219
 220         iface->state = state_idle;
 221         iface->result = -ENXIO;
 222
 223         outb(inb(ACBCTL1) | ACBCTL1_STOP, ACBCTL1);
 224         outb(ACBST_STASTR | ACBST_NEGACK, ACBST);
 225         return;
 226
 227  error:
 228         dev_err(&iface->adapter.dev, "%s in state %s\n", errmsg,
 229                 scx200_acb_state_name[iface->state]);
 230
 231         iface->state = state_idle;
 232         iface->result = -EIO;
 233         iface->needs_reset = 1;
 234 }
 235
 236 static void scx200_acb_timeout(struct scx200_acb_iface *iface)
 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 #ifdef POLLED_MODE
 247 static void scx200_acb_poll(struct scx200_acb_iface *iface)
 248 {
 249         u8 status = 0;
 250         unsigned long timeout;
 251
 252         timeout = jiffies + POLL_TIMEOUT;
 253         while (time_before(jiffies, timeout)) {
 254                 status = inb(ACBST);
 255                 if ((status & (ACBST_SDAST|ACBST_BER|ACBST_NEGACK)) != 0) {
 256                         scx200_acb_machine(iface, status);
 257                         return;
 258                 }
 259                 msleep(10);
 260         }
 261
 262         scx200_acb_timeout(iface);
 263 }
 264 #endif /* POLLED_MODE */
 265
 266 static void scx200_acb_reset(struct scx200_acb_iface *iface)
 267 {
 268         /* Disable the ACCESS.bus device and Configure the SCL
 269            frequency: 16 clock cycles */
 270         outb(0x70, ACBCTL2);
 271         /* Polling mode */
 272         outb(0, ACBCTL1);
 273         /* Disable slave address */
 274         outb(0, ACBADDR);
 275         /* Enable the ACCESS.bus device */
 276         outb(inb(ACBCTL2) | ACBCTL2_ENABLE, ACBCTL2);
 277         /* Free STALL after START */
 278         outb(inb(ACBCTL1) & ~(ACBCTL1_STASTRE | ACBCTL1_NMINTE), ACBCTL1);
 279         /* Send a STOP */
 280         outb(inb(ACBCTL1) | ACBCTL1_STOP, ACBCTL1);
 281         /* Clear BER, NEGACK and STASTR bits */
 282         outb(ACBST_BER | ACBST_NEGACK | ACBST_STASTR, ACBST);
 283         /* Clear BB bit */
 284         outb(inb(ACBCST) | ACBCST_BB, ACBCST);
 285 }
 286
 287 static s32 scx200_acb_smbus_xfer(struct i2c_adapter *adapter,
 288                                 u16 address, unsigned short flags,
 289                                 char rw, u8 command, int size,
 290                                 union i2c_smbus_data *data)
 291 {
 292         struct scx200_acb_iface *iface = i2c_get_adapdata(adapter);
 293         int len;
 294         u8 *buffer;
 295         u16 cur_word;
 296         int rc;
 297
 298         switch (size) {
 299         case I2C_SMBUS_QUICK:
 300                 len = 0;
 301                 buffer = NULL;
 302                 break;
 303         case I2C_SMBUS_BYTE:
 304                 if (rw == I2C_SMBUS_READ) {
 305                         len = 1;
 306                         buffer = &data->byte;
 307                 } else {
 308                         len = 1;
 309                         buffer = &command;
 310                 }
 311                 break;
 312         case I2C_SMBUS_BYTE_DATA:
 313                 len = 1;
 314                 buffer = &data->byte;
 315                 break;
 316         case I2C_SMBUS_WORD_DATA:
 317                 len = 2;
 318                 cur_word = cpu_to_le16(data->word);
 319                 buffer = (u8 *)&cur_word;
 320                 break;
 321         case I2C_SMBUS_BLOCK_DATA:
 322                 len = data->block[0];
 323                 buffer = &data->block[1];
 324                 break;
 325         default:
 326                 return -EINVAL;
 327         }
 328
 329         DBG("size=%d, address=0x%x, command=0x%x, len=%d, read=%d\n",
 330             size, address, command, len, rw == I2C_SMBUS_READ);
 331
 332         if (!len && rw == I2C_SMBUS_READ) {
 333                 dev_warn(&adapter->dev, "zero length read\n");
 334                 return -EINVAL;
 335         }
 336
 337         if (len && !buffer) {
 338                 dev_warn(&adapter->dev, "nonzero length but no buffer\n");
 339                 return -EFAULT;
 340         }
 341
 342         down(&iface->sem);
 343
 344         iface->address_byte = address<<1;
 345         if (rw == I2C_SMBUS_READ)
 346                 iface->address_byte |= 1;
 347         iface->command = command;
 348         iface->ptr = buffer;
 349         iface->len = len;
 350         iface->result = -EINVAL;
 351         iface->needs_reset = 0;
 352
 353         outb(inb(ACBCTL1) | ACBCTL1_START, ACBCTL1);
 354
 355         if (size == I2C_SMBUS_QUICK || size == I2C_SMBUS_BYTE)
 356                 iface->state = state_quick;
 357         else
 358                 iface->state = state_address;
 359
 360 #ifdef POLLED_MODE
 361         while (iface->state != state_idle)
 362                 scx200_acb_poll(iface);
 363 #else /* POLLED_MODE */
 364 #error Interrupt driven mode not implemented
 365 #endif /* POLLED_MODE */
 366
 367         if (iface->needs_reset)
 368                 scx200_acb_reset(iface);
 369
 370         rc = iface->result;
 371
 372         up(&iface->sem);
 373
 374         if (rc == 0 && size == I2C_SMBUS_WORD_DATA && rw == I2C_SMBUS_READ)
 375                 data->word = le16_to_cpu(cur_word);
 376
 377 #ifdef DEBUG
 378         DBG(": transfer done, result: %d", rc);
 379         if (buffer) {
 380                 int i;
 381                 printk(" data:");
 382                 for (i = 0; i < len; ++i)
 383                         printk(" %02x", buffer[i]);
 384         }
 385         printk("\n");
 386 #endif
 387
 388         return rc;
 389 }
 390
 391 static u32 scx200_acb_func(struct i2c_adapter *adapter)
 392 {
 393         return I2C_FUNC_SMBUS_QUICK | I2C_FUNC_SMBUS_BYTE |
 394                I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA |
 395                I2C_FUNC_SMBUS_BLOCK_DATA;
 396 }
 397
 398 /* For now, we only handle combined mode (smbus) */
 399 static struct i2c_algorithm scx200_acb_algorithm = {
 400         .name           = "NatSemi SCx200 ACCESS.bus",
 401         .id             = I2C_ALGO_SMBUS,
 402         .smbus_xfer     = scx200_acb_smbus_xfer,
 403         .functionality  = scx200_acb_func,
 404 };
 405
 406 struct scx200_acb_iface *scx200_acb_list;
 407
 408 int scx200_acb_probe(struct scx200_acb_iface *iface)
 409 {
 410         u8 val;
 411
 412         /* Disable the ACCESS.bus device and Configure the SCL
 413            frequency: 16 clock cycles */
 414         outb(0x70, ACBCTL2);
 415
 416         if (inb(ACBCTL2) != 0x70) {
 417                 DBG("ACBCTL2 readback failed\n");
 418                 return -ENXIO;
 419         }
 420
 421         outb(inb(ACBCTL1) | ACBCTL1_NMINTE, ACBCTL1);
 422
 423         val = inb(ACBCTL1);
 424         if (val) {
 425                 DBG("disabled, but ACBCTL1=0x%02x\n", val);
 426                 return -ENXIO;
 427         }
 428
 429         outb(inb(ACBCTL2) | ACBCTL2_ENABLE, ACBCTL2);
 430
 431         outb(inb(ACBCTL1) | ACBCTL1_NMINTE, ACBCTL1);
 432
 433         val = inb(ACBCTL1);
 434         if ((val & ACBCTL1_NMINTE) != ACBCTL1_NMINTE) {
 435                 DBG("enabled, but NMINTE won't be set, ACBCTL1=0x%02x\n", val);
 436                 return -ENXIO;
 437         }
 438
 439         return 0;
 440 }
 441
 442 static int  __init scx200_acb_create(int base, int index)
 443 {
 444         struct scx200_acb_iface *iface;
 445         struct i2c_adapter *adapter;
 446         int rc = 0;
 447         char description[64];
 448
 449         iface = kmalloc(sizeof(*iface), GFP_KERNEL);
 450         if (!iface) {
 451                 printk(KERN_ERR NAME ": can't allocate memory\n");
 452                 rc = -ENOMEM;
 453                 goto errout;
 454         }
 455
 456         memset(iface, 0, sizeof(*iface));
 457         adapter = &iface->adapter;
 458         i2c_set_adapdata(adapter, iface);
 459         snprintf(adapter->name, I2C_NAME_SIZE, "SCx200 ACB%d", index);
 460         adapter->owner = THIS_MODULE;
 461         adapter->id = I2C_ALGO_SMBUS;
 462         adapter->algo = &scx200_acb_algorithm;
 463         adapter->class = I2C_CLASS_HWMON;
 464
 465         init_MUTEX(&iface->sem);
 466
 467         snprintf(description, sizeof(description), "NatSemi SCx200 ACCESS.bus [%s]", adapter->name);
 468         if (request_region(base, 8, description) == 0) {
 469                 dev_err(&adapter->dev, "can't allocate io 0x%x-0x%x\n",
 470                         base, base + 8-1);
 471                 rc = -EBUSY;
 472                 goto errout;
 473         }
 474         iface->base = base;
 475
 476         rc = scx200_acb_probe(iface);
 477         if (rc) {
 478                 dev_warn(&adapter->dev, "probe failed\n");
 479                 goto errout;
 480         }
 481
 482         scx200_acb_reset(iface);
 483
 484         if (i2c_add_adapter(adapter) < 0) {
 485                 dev_err(&adapter->dev, "failed to register\n");
 486                 rc = -ENODEV;
 487                 goto errout;
 488         }
 489
 490         lock_kernel();
 491         iface->next = scx200_acb_list;
 492         scx200_acb_list = iface;
 493         unlock_kernel();
 494
 495         return 0;
 496
 497  errout:
 498         if (iface) {
 499                 if (iface->base)
 500                         release_region(iface->base, 8);
 501                 kfree(iface);
 502         }
 503         return rc;
 504 }
 505
 506 static int __init scx200_acb_init(void)
 507 {
 508         int i;
 509         int rc;
 510
 511         pr_debug(NAME ": NatSemi SCx200 ACCESS.bus Driver\n");
 512
 513         /* Verify that this really is a SCx200 processor */
 514         if (pci_find_device(PCI_VENDOR_ID_NS,
 515                             PCI_DEVICE_ID_NS_SCx200_BRIDGE,
 516                             NULL) == NULL
 517             && pci_find_device(PCI_VENDOR_ID_NS,
 518                                PCI_DEVICE_ID_NS_SC1100_BRIDGE,
 519                                NULL) == NULL)
 520                 return -ENODEV;
 521
 522         rc = -ENXIO;
 523         for (i = 0; i < MAX_DEVICES; ++i) {
 524                 if (base[i] > 0)
 525                         rc = scx200_acb_create(base[i], i);
 526         }
 527         if (scx200_acb_list)
 528                 return 0;
 529         return rc;
 530 }
 531
 532 static void __exit scx200_acb_cleanup(void)
 533 {
 534         struct scx200_acb_iface *iface;
 535         lock_kernel();
 536         while ((iface = scx200_acb_list) != NULL) {
 537                 scx200_acb_list = iface->next;
 538                 unlock_kernel();
 539
 540                 i2c_del_adapter(&iface->adapter);
 541                 release_region(iface->base, 8);
 542                 kfree(iface);
 543                 lock_kernel();
 544         }
 545         unlock_kernel();
 546 }
 547
 548 module_init(scx200_acb_init);
 549 module_exit(scx200_acb_cleanup);
 550
 551 /*
 552     Local variables:
 553         compile-command: "make -k -C ../.. SUBDIRS=drivers/i2c modules"
 554         c-basic-offset: 8
 555     End:
 556 */
 557