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 module_param_array(base, int, NULL, 0);
  49 MODULE_PARM_DESC(base, "Base addresses for the ACCESS.bus controllers");
  50
  51 #ifdef DEBUG
  52 #define DBG(x...) printk(KERN_DEBUG NAME ": " x)
  53 #else
  54 #define DBG(x...)
  55 #endif
  56
  57 /* The hardware supports interrupt driven mode too, but I haven't
  58    implemented that. */
  59 #define POLLED_MODE 1
  60 #define POLL_TIMEOUT (HZ)
  61
  62 enum scx200_acb_state {
  63         state_idle,
  64         state_address,
  65         state_command,
  66         state_repeat_start,
  67         state_quick,
  68         state_read,
  69         state_write,
  70 };
  71
  72 static const char *scx200_acb_state_name[] = {
  73         "idle",
  74         "address",
  75         "command",
  76         "repeat_start",
  77         "quick",
  78         "read",
  79         "write",
  80 };
  81
  82 /* Physical interface */
  83 struct scx200_acb_iface
  84 {
  85         struct scx200_acb_iface *next;
  86         struct i2c_adapter adapter;
  87         unsigned base;
  88         struct semaphore sem;
  89
  90         /* State machine data */
  91         enum scx200_acb_state state;
  92         int result;
  93         u8 address_byte;
  94         u8 command;
  95         u8 *ptr;
  96         char needs_reset;
  97         unsigned len;
  98 };
  99
 100 /* Register Definitions */
 101 #define ACBSDA          (iface->base + 0)
 102 #define ACBST           (iface->base + 1)
 103 #define    ACBST_SDAST          0x40 /* SDA Status */
 104 #define    ACBST_BER            0x20
 105 #define    ACBST_NEGACK         0x10 /* Negative Acknowledge */
 106 #define    ACBST_STASTR         0x08 /* Stall After Start */
 107 #define    ACBST_MASTER         0x02
 108 #define ACBCST          (iface->base + 2)
 109 #define    ACBCST_BB            0x02
 110 #define ACBCTL1         (iface->base + 3)
 111 #define    ACBCTL1_STASTRE      0x80
 112 #define    ACBCTL1_NMINTE       0x40
 113 #define    ACBCTL1_ACK          0x10
 114 #define    ACBCTL1_STOP         0x02
 115 #define    ACBCTL1_START        0x01
 116 #define ACBADDR         (iface->base + 4)
 117 #define ACBCTL2         (iface->base + 5)
 118 #define    ACBCTL2_ENABLE       0x01
 119
 120 /************************************************************************/
 121
 122 static void scx200_acb_machine(struct scx200_acb_iface *iface, u8 status)
 123 {
 124         const char *errmsg;
 125
 126         DBG("state %s, status = 0x%02x\n",
 127             scx200_acb_state_name[iface->state], status);
 128
 129         if (status & ACBST_BER) {
 130                 errmsg = "bus error";
 131                 goto error;
 132         }
 133         if (!(status & ACBST_MASTER)) {
 134                 errmsg = "not master";
 135                 goto error;
 136         }
 137         if (status & ACBST_NEGACK)
 138                 goto negack;
 139
 140         switch (iface->state) {
 141         case state_idle:
 142                 dev_warn(&iface->adapter.dev, "interrupt in idle state\n");
 143                 break;
 144
 145         case state_address:
 146                 /* Do a pointer write first */
 147                 outb(iface->address_byte & ~1, ACBSDA);
 148
 149                 iface->state = state_command;
 150                 break;
 151
 152         case state_command:
 153                 outb(iface->command, ACBSDA);
 154
 155                 if (iface->address_byte & 1)
 156                         iface->state = state_repeat_start;
 157                 else
 158                         iface->state = state_write;
 159                 break;
 160
 161         case state_repeat_start:
 162                 outb(inb(ACBCTL1) | ACBCTL1_START, ACBCTL1);
 163                 /* fallthrough */
 164
 165         case state_quick:
 166                 if (iface->address_byte & 1) {
 167                         if (iface->len == 1)
 168                                 outb(inb(ACBCTL1) | ACBCTL1_ACK, ACBCTL1);
 169                         else
 170                                 outb(inb(ACBCTL1) & ~ACBCTL1_ACK, ACBCTL1);
 171                         outb(iface->address_byte, ACBSDA);
 172
 173                         iface->state = state_read;
 174                 } else {
 175                         outb(iface->address_byte, ACBSDA);
 176
 177                         iface->state = state_write;
 178                 }
 179                 break;
 180
 181         case state_read:
 182                 /* Set ACK if receiving the last byte */
 183                 if (iface->len == 1)
 184                         outb(inb(ACBCTL1) | ACBCTL1_ACK, ACBCTL1);
 185                 else
 186                         outb(inb(ACBCTL1) & ~ACBCTL1_ACK, ACBCTL1);
 187
 188                 *iface->ptr++ = inb(ACBSDA);
 189                 --iface->len;
 190
 191                 if (iface->len == 0) {
 192                         iface->result = 0;
 193                         iface->state = state_idle;
 194                         outb(inb(ACBCTL1) | ACBCTL1_STOP, ACBCTL1);
 195                 }
 196
 197                 break;
 198
 199         case state_write:
 200                 if (iface->len == 0) {
 201                         iface->result = 0;
 202                         iface->state = state_idle;
 203                         outb(inb(ACBCTL1) | ACBCTL1_STOP, ACBCTL1);
 204                         break;
 205                 }
 206
 207                 outb(*iface->ptr++, ACBSDA);
 208                 --iface->len;
 209
 210                 break;
 211         }
 212
 213         return;
 214
 215  negack:
 216         DBG("negative acknowledge in state %s\n",
 217             scx200_acb_state_name[iface->state]);
 218
 219         iface->state = state_idle;
 220         iface->result = -ENXIO;
 221
 222         outb(inb(ACBCTL1) | ACBCTL1_STOP, ACBCTL1);
 223         outb(ACBST_STASTR | ACBST_NEGACK, ACBST);
 224         return;
 225
 226  error:
 227         dev_err(&iface->adapter.dev, "%s in state %s\n", errmsg,
 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 static void scx200_acb_timeout(struct scx200_acb_iface *iface)
 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 #ifdef POLLED_MODE
 246 static void scx200_acb_poll(struct scx200_acb_iface *iface)
 247 {
 248         u8 status = 0;
 249         unsigned long timeout;
 250
 251         timeout = jiffies + POLL_TIMEOUT;
 252         while (time_before(jiffies, timeout)) {
 253                 status = inb(ACBST);
 254                 if ((status & (ACBST_SDAST|ACBST_BER|ACBST_NEGACK)) != 0) {
 255                         scx200_acb_machine(iface, status);
 256                         return;
 257                 }
 258                 msleep(10);
 259         }
 260
 261         scx200_acb_timeout(iface);
 262 }
 263 #endif /* POLLED_MODE */
 264
 265 static void scx200_acb_reset(struct scx200_acb_iface *iface)
 266 {
 267         /* Disable the ACCESS.bus device and Configure the SCL
 268            frequency: 16 clock cycles */
 269         outb(0x70, ACBCTL2);
 270         /* Polling mode */
 271         outb(0, ACBCTL1);
 272         /* Disable slave address */
 273         outb(0, ACBADDR);
 274         /* Enable the ACCESS.bus device */
 275         outb(inb(ACBCTL2) | ACBCTL2_ENABLE, ACBCTL2);
 276         /* Free STALL after START */
 277         outb(inb(ACBCTL1) & ~(ACBCTL1_STASTRE | ACBCTL1_NMINTE), ACBCTL1);
 278         /* Send a STOP */
 279         outb(inb(ACBCTL1) | ACBCTL1_STOP, ACBCTL1);
 280         /* Clear BER, NEGACK and STASTR bits */
 281         outb(ACBST_BER | ACBST_NEGACK | ACBST_STASTR, ACBST);
 282         /* Clear BB bit */
 283         outb(inb(ACBCST) | ACBCST_BB, ACBCST);
 284 }
 285
 286 static s32 scx200_acb_smbus_xfer(struct i2c_adapter *adapter,
 287                                 u16 address, unsigned short flags,
 288                                 char rw, u8 command, int size,
 289                                 union i2c_smbus_data *data)
 290 {
 291         struct scx200_acb_iface *iface = i2c_get_adapdata(adapter);
 292         int len;
 293         u8 *buffer;
 294         u16 cur_word;
 295         int rc;
 296
 297         switch (size) {
 298         case I2C_SMBUS_QUICK:
 299                 len = 0;
 300                 buffer = NULL;
 301                 break;
 302         case I2C_SMBUS_BYTE:
 303                 if (rw == I2C_SMBUS_READ) {
 304                         len = 1;
 305                         buffer = &data->byte;
 306                 } else {
 307                         len = 1;
 308                         buffer = &command;
 309                 }
 310                 break;
 311         case I2C_SMBUS_BYTE_DATA:
 312                 len = 1;
 313                 buffer = &data->byte;
 314                 break;
 315         case I2C_SMBUS_WORD_DATA:
 316                 len = 2;
 317                 cur_word = cpu_to_le16(data->word);
 318                 buffer = (u8 *)&cur_word;
 319                 break;
 320         case I2C_SMBUS_BLOCK_DATA:
 321                 len = data->block[0];
 322                 buffer = &data->block[1];
 323                 break;
 324         default:
 325                 return -EINVAL;
 326         }
 327
 328         DBG("size=%d, address=0x%x, command=0x%x, len=%d, read=%d\n",
 329             size, address, command, len, rw == I2C_SMBUS_READ);
 330
 331         if (!len && rw == I2C_SMBUS_READ) {
 332                 dev_warn(&adapter->dev, "zero length read\n");
 333                 return -EINVAL;
 334         }
 335
 336         if (len && !buffer) {
 337                 dev_warn(&adapter->dev, "nonzero length but no buffer\n");
 338                 return -EFAULT;
 339         }
 340
 341         down(&iface->sem);
 342
 343         iface->address_byte = address<<1;
 344         if (rw == I2C_SMBUS_READ)
 345                 iface->address_byte |= 1;
 346         iface->command = command;
 347         iface->ptr = buffer;
 348         iface->len = len;
 349         iface->result = -EINVAL;
 350         iface->needs_reset = 0;
 351
 352         outb(inb(ACBCTL1) | ACBCTL1_START, ACBCTL1);
 353
 354         if (size == I2C_SMBUS_QUICK || size == I2C_SMBUS_BYTE)
 355                 iface->state = state_quick;
 356         else
 357                 iface->state = state_address;
 358
 359 #ifdef POLLED_MODE
 360         while (iface->state != state_idle)
 361                 scx200_acb_poll(iface);
 362 #else /* POLLED_MODE */
 363 #error Interrupt driven mode not implemented
 364 #endif /* POLLED_MODE */
 365
 366         if (iface->needs_reset)
 367                 scx200_acb_reset(iface);
 368
 369         rc = iface->result;
 370
 371         up(&iface->sem);
 372
 373         if (rc == 0 && size == I2C_SMBUS_WORD_DATA && rw == I2C_SMBUS_READ)
 374                 data->word = le16_to_cpu(cur_word);
 375
 376 #ifdef DEBUG
 377         DBG(": transfer done, result: %d", rc);
 378         if (buffer) {
 379                 int i;
 380                 printk(" data:");
 381                 for (i = 0; i < len; ++i)
 382                         printk(" %02x", buffer[i]);
 383         }
 384         printk("\n");
 385 #endif
 386
 387         return rc;
 388 }
 389
 390 static u32 scx200_acb_func(struct i2c_adapter *adapter)
 391 {
 392         return I2C_FUNC_SMBUS_QUICK | I2C_FUNC_SMBUS_BYTE |
 393                I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA |
 394                I2C_FUNC_SMBUS_BLOCK_DATA;
 395 }
 396
 397 /* For now, we only handle combined mode (smbus) */
 398 static struct i2c_algorithm scx200_acb_algorithm = {
 399         .name           = "NatSemi SCx200 ACCESS.bus",
 400         .id             = I2C_ALGO_SMBUS,
 401         .smbus_xfer     = scx200_acb_smbus_xfer,
 402         .functionality  = scx200_acb_func,
 403 };
 404
 405 static struct scx200_acb_iface *scx200_acb_list;
 406
 407 static int scx200_acb_probe(struct scx200_acb_iface *iface)
 408 {
 409         u8 val;
 410
 411         /* Disable the ACCESS.bus device and Configure the SCL
 412            frequency: 16 clock cycles */
 413         outb(0x70, ACBCTL2);
 414
 415         if (inb(ACBCTL2) != 0x70) {
 416                 DBG("ACBCTL2 readback failed\n");
 417                 return -ENXIO;
 418         }
 419
 420         outb(inb(ACBCTL1) | ACBCTL1_NMINTE, ACBCTL1);
 421
 422         val = inb(ACBCTL1);
 423         if (val) {
 424                 DBG("disabled, but ACBCTL1=0x%02x\n", val);
 425                 return -ENXIO;
 426         }
 427
 428         outb(inb(ACBCTL2) | ACBCTL2_ENABLE, ACBCTL2);
 429
 430         outb(inb(ACBCTL1) | ACBCTL1_NMINTE, ACBCTL1);
 431
 432         val = inb(ACBCTL1);
 433         if ((val & ACBCTL1_NMINTE) != ACBCTL1_NMINTE) {
 434                 DBG("enabled, but NMINTE won't be set, ACBCTL1=0x%02x\n", val);
 435                 return -ENXIO;
 436         }
 437
 438         return 0;
 439 }
 440
 441 static int  __init scx200_acb_create(int base, int index)
 442 {
 443         struct scx200_acb_iface *iface;
 444         struct i2c_adapter *adapter;
 445         int rc = 0;
 446         char description[64];
 447
 448         iface = kmalloc(sizeof(*iface), GFP_KERNEL);
 449         if (!iface) {
 450                 printk(KERN_ERR NAME ": can't allocate memory\n");
 451                 rc = -ENOMEM;
 452                 goto errout;
 453         }
 454
 455         memset(iface, 0, sizeof(*iface));
 456         adapter = &iface->adapter;
 457         i2c_set_adapdata(adapter, iface);
 458         snprintf(adapter->name, I2C_NAME_SIZE, "SCx200 ACB%d", index);
 459         adapter->owner = THIS_MODULE;
 460         adapter->id = I2C_ALGO_SMBUS;
 461         adapter->algo = &scx200_acb_algorithm;
 462         adapter->class = I2C_CLASS_HWMON;
 463
 464         init_MUTEX(&iface->sem);
 465
 466         snprintf(description, sizeof(description), "NatSemi SCx200 ACCESS.bus [%s]", adapter->name);
 467         if (request_region(base, 8, description) == 0) {
 468                 dev_err(&adapter->dev, "can't allocate io 0x%x-0x%x\n",
 469                         base, base + 8-1);
 470                 rc = -EBUSY;
 471                 goto errout;
 472         }
 473         iface->base = base;
 474
 475         rc = scx200_acb_probe(iface);
 476         if (rc) {
 477                 dev_warn(&adapter->dev, "probe failed\n");
 478                 goto errout;
 479         }
 480
 481         scx200_acb_reset(iface);
 482
 483         if (i2c_add_adapter(adapter) < 0) {
 484                 dev_err(&adapter->dev, "failed to register\n");
 485                 rc = -ENODEV;
 486                 goto errout;
 487         }
 488
 489         lock_kernel();
 490         iface->next = scx200_acb_list;
 491         scx200_acb_list = iface;
 492         unlock_kernel();
 493
 494         return 0;
 495
 496  errout:
 497         if (iface) {
 498                 if (iface->base)
 499                         release_region(iface->base, 8);
 500                 kfree(iface);
 501         }
 502         return rc;
 503 }
 504
 505 static struct pci_device_id scx200[] = {
 506         { PCI_DEVICE(PCI_VENDOR_ID_NS, PCI_DEVICE_ID_NS_SCx200_BRIDGE) },
 507         { PCI_DEVICE(PCI_VENDOR_ID_NS, PCI_DEVICE_ID_NS_SC1100_BRIDGE) },
 508         { },
 509 };
 510
 511 static int __init scx200_acb_init(void)
 512 {
 513         int i;
 514         int rc;
 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) == 0)
 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