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                 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 #ifdef POLLED_MODE
 224 static void scx200_acb_poll(struct scx200_acb_iface *iface)
 225 {
 226         u8 status;
 227         unsigned long timeout;
 228
 229         timeout = jiffies + POLL_TIMEOUT;
 230         while (time_before(jiffies, timeout)) {
 231                 status = inb(ACBST);
 232                 if ((status & (ACBST_SDAST|ACBST_BER|ACBST_NEGACK)) != 0) {
 233                         scx200_acb_machine(iface, status);
 234                         return;
 235                 }
 236                 msleep(10);
 237         }
 238
 239         dev_err(&iface->adapter.dev, "timeout in state %s\n",
 240                 scx200_acb_state_name[iface->state]);
 241
 242         iface->state = state_idle;
 243         iface->result = -EIO;
 244         iface->needs_reset = 1;
 245 }
 246 #endif /* POLLED_MODE */
 247
 248 static void scx200_acb_reset(struct scx200_acb_iface *iface)
 249 {
 250         /* Disable the ACCESS.bus device and Configure the SCL
 251            frequency: 16 clock cycles */
 252         outb(0x70, ACBCTL2);
 253         /* Polling mode */
 254         outb(0, ACBCTL1);
 255         /* Disable slave address */
 256         outb(0, ACBADDR);
 257         /* Enable the ACCESS.bus device */
 258         outb(inb(ACBCTL2) | ACBCTL2_ENABLE, ACBCTL2);
 259         /* Free STALL after START */
 260         outb(inb(ACBCTL1) & ~(ACBCTL1_STASTRE | ACBCTL1_NMINTE), ACBCTL1);
 261         /* Send a STOP */
 262         outb(inb(ACBCTL1) | ACBCTL1_STOP, ACBCTL1);
 263         /* Clear BER, NEGACK and STASTR bits */
 264         outb(ACBST_BER | ACBST_NEGACK | ACBST_STASTR, ACBST);
 265         /* Clear BB bit */
 266         outb(inb(ACBCST) | ACBCST_BB, ACBCST);
 267 }
 268
 269 static s32 scx200_acb_smbus_xfer(struct i2c_adapter *adapter,
 270                                  u16 address, unsigned short flags,
 271                                  char rw, u8 command, int size,
 272                                  union i2c_smbus_data *data)
 273 {
 274         struct scx200_acb_iface *iface = i2c_get_adapdata(adapter);
 275         int len;
 276         u8 *buffer;
 277         u16 cur_word;
 278         int rc;
 279
 280         switch (size) {
 281         case I2C_SMBUS_QUICK:
 282                 len = 0;
 283                 buffer = NULL;
 284                 break;
 285
 286         case I2C_SMBUS_BYTE:
 287                 len = 1;
 288                 buffer = rw ? &data->byte : &command;
 289                 break;
 290
 291         case I2C_SMBUS_BYTE_DATA:
 292                 len = 1;
 293                 buffer = &data->byte;
 294                 break;
 295
 296         case I2C_SMBUS_WORD_DATA:
 297                 len = 2;
 298                 cur_word = cpu_to_le16(data->word);
 299                 buffer = (u8 *)&cur_word;
 300                 break;
 301
 302         case I2C_SMBUS_BLOCK_DATA:
 303                 len = data->block[0];
 304                 buffer = &data->block[1];
 305                 break;
 306
 307         default:
 308                 return -EINVAL;
 309         }
 310
 311         dev_dbg(&adapter->dev,
 312                 "size=%d, address=0x%x, command=0x%x, len=%d, read=%d\n",
 313                 size, address, command, len, rw);
 314
 315         if (!len && rw == I2C_SMBUS_READ) {
 316                 dev_dbg(&adapter->dev, "zero length read\n");
 317                 return -EINVAL;
 318         }
 319
 320         down(&iface->sem);
 321
 322         iface->address_byte = (address << 1) | rw;
 323         iface->command = command;
 324         iface->ptr = buffer;
 325         iface->len = len;
 326         iface->result = -EINVAL;
 327         iface->needs_reset = 0;
 328
 329         outb(inb(ACBCTL1) | ACBCTL1_START, ACBCTL1);
 330
 331         if (size == I2C_SMBUS_QUICK || size == I2C_SMBUS_BYTE)
 332                 iface->state = state_quick;
 333         else
 334                 iface->state = state_address;
 335
 336 #ifdef POLLED_MODE
 337         while (iface->state != state_idle)
 338                 scx200_acb_poll(iface);
 339 #else /* POLLED_MODE */
 340 #error Interrupt driven mode not implemented
 341 #endif /* POLLED_MODE */
 342
 343         if (iface->needs_reset)
 344                 scx200_acb_reset(iface);
 345
 346         rc = iface->result;
 347
 348         up(&iface->sem);
 349
 350         if (rc == 0 && size == I2C_SMBUS_WORD_DATA && rw == I2C_SMBUS_READ)
 351                 data->word = le16_to_cpu(cur_word);
 352
 353 #ifdef DEBUG
 354         dev_dbg(&adapter->dev, "transfer done, result: %d", rc);
 355         if (buffer) {
 356                 int i;
 357                 printk(" data:");
 358                 for (i = 0; i < len; ++i)
 359                         printk(" %02x", buffer[i]);
 360         }
 361         printk("\n");
 362 #endif
 363
 364         return rc;
 365 }
 366
 367 static u32 scx200_acb_func(struct i2c_adapter *adapter)
 368 {
 369         return I2C_FUNC_SMBUS_QUICK | I2C_FUNC_SMBUS_BYTE |
 370                I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA |
 371                I2C_FUNC_SMBUS_BLOCK_DATA;
 372 }
 373
 374 /* For now, we only handle combined mode (smbus) */
 375 static struct i2c_algorithm scx200_acb_algorithm = {
 376         .smbus_xfer     = scx200_acb_smbus_xfer,
 377         .functionality  = scx200_acb_func,
 378 };
 379
 380 static struct scx200_acb_iface *scx200_acb_list;
 381 static DECLARE_MUTEX(scx200_acb_list_mutex);
 382
 383 static int scx200_acb_probe(struct scx200_acb_iface *iface)
 384 {
 385         u8 val;
 386
 387         /* Disable the ACCESS.bus device and Configure the SCL
 388            frequency: 16 clock cycles */
 389         outb(0x70, ACBCTL2);
 390
 391         if (inb(ACBCTL2) != 0x70) {
 392                 pr_debug(NAME ": ACBCTL2 readback failed\n");
 393                 return -ENXIO;
 394         }
 395
 396         outb(inb(ACBCTL1) | ACBCTL1_NMINTE, ACBCTL1);
 397
 398         val = inb(ACBCTL1);
 399         if (val) {
 400                 pr_debug(NAME ": disabled, but ACBCTL1=0x%02x\n",
 401                         val);
 402                 return -ENXIO;
 403         }
 404
 405         outb(inb(ACBCTL2) | ACBCTL2_ENABLE, ACBCTL2);
 406
 407         outb(inb(ACBCTL1) | ACBCTL1_NMINTE, ACBCTL1);
 408
 409         val = inb(ACBCTL1);
 410         if ((val & ACBCTL1_NMINTE) != ACBCTL1_NMINTE) {
 411                 pr_debug(NAME ": enabled, but NMINTE won't be set, "
 412                          "ACBCTL1=0x%02x\n", val);
 413                 return -ENXIO;
 414         }
 415
 416         return 0;
 417 }
 418
 419 static int  __init scx200_acb_create(int base, int index)
 420 {
 421         struct scx200_acb_iface *iface;
 422         struct i2c_adapter *adapter;
 423         int rc;
 424         char description[64];
 425
 426         iface = kzalloc(sizeof(*iface), GFP_KERNEL);
 427         if (!iface) {
 428                 printk(KERN_ERR NAME ": can't allocate memory\n");
 429                 rc = -ENOMEM;
 430                 goto errout;
 431         }
 432
 433         adapter = &iface->adapter;
 434         i2c_set_adapdata(adapter, iface);
 435         snprintf(adapter->name, I2C_NAME_SIZE, "SCx200 ACB%d", index);
 436         adapter->owner = THIS_MODULE;
 437         adapter->id = I2C_HW_SMBUS_SCX200;
 438         adapter->algo = &scx200_acb_algorithm;
 439         adapter->class = I2C_CLASS_HWMON;
 440
 441         init_MUTEX(&iface->sem);
 442
 443         snprintf(description, sizeof(description),
 444                  "NatSemi SCx200 ACCESS.bus [%s]", adapter->name);
 445         if (request_region(base, 8, description) == 0) {
 446                 printk(KERN_ERR NAME ": can't allocate io 0x%x-0x%x\n",
 447                         base, base + 8-1);
 448                 rc = -EBUSY;
 449                 goto errout_free;
 450         }
 451         iface->base = base;
 452
 453         rc = scx200_acb_probe(iface);
 454         if (rc) {
 455                 printk(KERN_WARNING NAME ": probe failed\n");
 456                 goto errout_release;
 457         }
 458
 459         scx200_acb_reset(iface);
 460
 461         if (i2c_add_adapter(adapter) < 0) {
 462                 printk(KERN_ERR NAME ": failed to register\n");
 463                 rc = -ENODEV;
 464                 goto errout_release;
 465         }
 466
 467         down(&scx200_acb_list_mutex);
 468         iface->next = scx200_acb_list;
 469         scx200_acb_list = iface;
 470         up(&scx200_acb_list_mutex);
 471
 472         return 0;
 473
 474  errout_release:
 475         release_region(iface->base, 8);
 476  errout_free:
 477         kfree(iface);
 478  errout:
 479         return rc;
 480 }
 481
 482 static struct pci_device_id scx200[] = {
 483         { PCI_DEVICE(PCI_VENDOR_ID_NS, PCI_DEVICE_ID_NS_SCx200_BRIDGE) },
 484         { PCI_DEVICE(PCI_VENDOR_ID_NS, PCI_DEVICE_ID_NS_SC1100_BRIDGE) },
 485         { },
 486 };
 487
 488 static int __init scx200_acb_init(void)
 489 {
 490         int i;
 491         int rc;
 492
 493         pr_debug(NAME ": NatSemi SCx200 ACCESS.bus Driver\n");
 494
 495         /* Verify that this really is a SCx200 processor */
 496         if (pci_dev_present(scx200) == 0)
 497                 return -ENODEV;
 498
 499         rc = -ENXIO;
 500         for (i = 0; i < MAX_DEVICES; ++i) {
 501                 if (base[i] > 0)
 502                         rc = scx200_acb_create(base[i], i);
 503         }
 504         if (scx200_acb_list)
 505                 return 0;
 506         return rc;
 507 }
 508
 509 static void __exit scx200_acb_cleanup(void)
 510 {
 511         struct scx200_acb_iface *iface;
 512
 513         down(&scx200_acb_list_mutex);
 514         while ((iface = scx200_acb_list) != NULL) {
 515                 scx200_acb_list = iface->next;
 516                 up(&scx200_acb_list_mutex);
 517
 518                 i2c_del_adapter(&iface->adapter);
 519                 release_region(iface->base, 8);
 520                 kfree(iface);
 521                 down(&scx200_acb_list_mutex);
 522         }
 523         up(&scx200_acb_list_mutex);
 524 }
 525
 526 module_init(scx200_acb_init);
 527 module_exit(scx200_acb_cleanup);