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 <asm/io.h>
  36
  37 #include <linux/scx200.h>
  38
  39 #define NAME "scx200_acb"
  40
  41 MODULE_AUTHOR("Christer Weinigel <wingel@nano-system.com>");
  42 MODULE_DESCRIPTION("NatSemi SCx200 ACCESS.bus Driver");
  43 MODULE_LICENSE("GPL");
  44
  45 #define MAX_DEVICES 4
  46 static int base[MAX_DEVICES] = { 0x820, 0x840 };
  47 MODULE_PARM(base, "1-4i");
  48 MODULE_PARM_DESC(base, "Base addresses for the ACCESS.bus controllers");
  49
  50 #ifdef DEBUG
  51 #define DBG(x...) printk(KERN_DEBUG NAME ": " x)
  52 #else
  53 #define DBG(x...)
  54 #endif
  55
  56 /* The hardware supports interrupt driven mode too, but I haven't
  57    implemented that. */
  58 #define POLLED_MODE 1
  59 #define POLL_TIMEOUT (HZ)
  60
  61 enum scx200_acb_state {
  62         state_idle,
  63         state_address,
  64         state_command,
  65         state_repeat_start,
  66         state_quick,
  67         state_read,
  68         state_write,
  69 };
  70
  71 static const char *scx200_acb_state_name[] = {
  72         "idle",
  73         "address",
  74         "command",
  75         "repeat_start",
  76         "quick",
  77         "read",
  78         "write",
  79 };
  80
  81 /* Physical interface */
  82 struct scx200_acb_iface
  83 {
  84         struct scx200_acb_iface *next;
  85         struct i2c_adapter adapter;
  86         unsigned base;
  87         struct semaphore sem;
  88
  89         /* State machine data */
  90         enum scx200_acb_state state;
  91         int result;
  92         u8 address_byte;
  93         u8 command;
  94         u8 *ptr;
  95         char needs_reset;
  96         unsigned len;
  97 };
  98
  99 /* Register Definitions */
 100 #define ACBSDA          (iface->base + 0)
 101 #define ACBST           (iface->base + 1)
 102 #define    ACBST_SDAST          0x40 /* SDA Status */
 103 #define    ACBST_BER            0x20
 104 #define    ACBST_NEGACK         0x10 /* Negative Acknowledge */
 105 #define    ACBST_STASTR         0x08 /* Stall After Start */
 106 #define    ACBST_MASTER         0x02
 107 #define ACBCST          (iface->base + 2)
 108 #define    ACBCST_BB            0x02
 109 #define ACBCTL1         (iface->base + 3)
 110 #define    ACBCTL1_STASTRE      0x80
 111 #define    ACBCTL1_NMINTE       0x40
 112 #define    ACBCTL1_ACK          0x10
 113 #define    ACBCTL1_STOP         0x02
 114 #define    ACBCTL1_START        0x01
 115 #define ACBADDR         (iface->base + 4)
 116 #define ACBCTL2         (iface->base + 5)
 117 #define    ACBCTL2_ENABLE       0x01
 118
 119 /************************************************************************/
 120
 121 static void scx200_acb_machine(struct scx200_acb_iface *iface, u8 status)
 122 {
 123         const char *errmsg;
 124
 125         DBG("state %s, status = 0x%02x\n",
 126             scx200_acb_state_name[iface->state], status);
 127
 128         if (status & ACBST_BER) {
 129                 errmsg = "bus error";
 130                 goto error;
 131         }
 132         if (!(status & ACBST_MASTER)) {
 133                 errmsg = "not master";
 134                 goto error;
 135         }
 136         if (status & ACBST_NEGACK)
 137                 goto negack;
 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  negack:
 215         DBG("negative acknowledge in state %s\n",
 216             scx200_acb_state_name[iface->state]);
 217
 218         iface->state = state_idle;
 219         iface->result = -ENXIO;
 220
 221         outb(inb(ACBCTL1) | ACBCTL1_STOP, ACBCTL1);
 222         outb(ACBST_STASTR | ACBST_NEGACK, ACBST);
 223         return;
 224
 225  error:
 226         dev_err(&iface->adapter.dev, "%s in state %s\n", errmsg,
 227                 scx200_acb_state_name[iface->state]);
 228
 229         iface->state = state_idle;
 230         iface->result = -EIO;
 231         iface->needs_reset = 1;
 232 }
 233
 234 static void scx200_acb_timeout(struct scx200_acb_iface *iface)
 235 {
 236         dev_err(&iface->adapter.dev, "timeout in state %s\n",
 237                 scx200_acb_state_name[iface->state]);
 238
 239         iface->state = state_idle;
 240         iface->result = -EIO;
 241         iface->needs_reset = 1;
 242 }
 243
 244 #ifdef POLLED_MODE
 245 static void scx200_acb_poll(struct scx200_acb_iface *iface)
 246 {
 247         u8 status = 0;
 248         unsigned long timeout;
 249
 250         timeout = jiffies + POLL_TIMEOUT;
 251         while (time_before(jiffies, timeout)) {
 252                 status = inb(ACBST);
 253                 if ((status & (ACBST_SDAST|ACBST_BER|ACBST_NEGACK)) != 0) {
 254                         scx200_acb_machine(iface, status);
 255                         return;
 256                 }
 257                 schedule_timeout(HZ/100+1);
 258         }
 259
 260         scx200_acb_timeout(iface);
 261 }
 262 #endif /* POLLED_MODE */
 263
 264 static void scx200_acb_reset(struct scx200_acb_iface *iface)
 265 {
 266         /* Disable the ACCESS.bus device and Configure the SCL
 267            frequency: 16 clock cycles */
 268         outb(0x70, ACBCTL2);
 269         /* Polling mode */
 270         outb(0, ACBCTL1);
 271         /* Disable slave address */
 272         outb(0, ACBADDR);
 273         /* Enable the ACCESS.bus device */
 274         outb(inb(ACBCTL2) | ACBCTL2_ENABLE, ACBCTL2);
 275         /* Free STALL after START */
 276         outb(inb(ACBCTL1) & ~(ACBCTL1_STASTRE | ACBCTL1_NMINTE), ACBCTL1);
 277         /* Send a STOP */
 278         outb(inb(ACBCTL1) | ACBCTL1_STOP, ACBCTL1);
 279         /* Clear BER, NEGACK and STASTR bits */
 280         outb(ACBST_BER | ACBST_NEGACK | ACBST_STASTR, ACBST);
 281         /* Clear BB bit */
 282         outb(inb(ACBCST) | ACBCST_BB, ACBCST);
 283 }
 284
 285 static s32 scx200_acb_smbus_xfer(struct i2c_adapter *adapter,
 286                                 u16 address, unsigned short flags,
 287                                 char rw, u8 command, int size,
 288                                 union i2c_smbus_data *data)
 289 {
 290         struct scx200_acb_iface *iface = i2c_get_adapdata(adapter);
 291         int len;
 292         u8 *buffer;
 293         u16 cur_word;
 294         int rc;
 295
 296         switch (size) {
 297         case I2C_SMBUS_QUICK:
 298                 len = 0;
 299                 buffer = NULL;
 300                 break;
 301         case I2C_SMBUS_BYTE:
 302                 if (rw == I2C_SMBUS_READ) {
 303                         len = 1;
 304                         buffer = &data->byte;
 305                 } else {
 306                         len = 1;
 307                         buffer = &command;
 308                 }
 309                 break;
 310         case I2C_SMBUS_BYTE_DATA:
 311                 len = 1;
 312                 buffer = &data->byte;
 313                 break;
 314         case I2C_SMBUS_WORD_DATA:
 315                 len = 2;
 316                 cur_word = cpu_to_le16(data->word);
 317                 buffer = (u8 *)&cur_word;
 318                 break;
 319         case I2C_SMBUS_BLOCK_DATA:
 320                 len = data->block[0];
 321                 buffer = &data->block[1];
 322                 break;
 323         default:
 324                 return -EINVAL;
 325         }
 326
 327         DBG("size=%d, address=0x%x, command=0x%x, len=%d, read=%d\n",
 328             size, address, command, len, rw == I2C_SMBUS_READ);
 329
 330         if (!len && rw == I2C_SMBUS_READ) {
 331                 dev_warn(&adapter->dev, "zero length read\n");
 332                 return -EINVAL;
 333         }
 334
 335         if (len && !buffer) {
 336                 dev_warn(&adapter->dev, "nonzero length but no buffer\n");
 337                 return -EFAULT;
 338         }
 339
 340         down(&iface->sem);
 341
 342         iface->address_byte = address<<1;
 343         if (rw == I2C_SMBUS_READ)
 344                 iface->address_byte |= 1;
 345         iface->command = command;
 346         iface->ptr = buffer;
 347         iface->len = len;
 348         iface->result = -EINVAL;
 349         iface->needs_reset = 0;
 350
 351         outb(inb(ACBCTL1) | ACBCTL1_START, ACBCTL1);
 352
 353         if (size == I2C_SMBUS_QUICK || size == I2C_SMBUS_BYTE)
 354                 iface->state = state_quick;
 355         else
 356                 iface->state = state_address;
 357
 358 #ifdef POLLED_MODE
 359         while (iface->state != state_idle)
 360                 scx200_acb_poll(iface);
 361 #else /* POLLED_MODE */
 362 #error Interrupt driven mode not implemented
 363 #endif /* POLLED_MODE */
 364
 365         if (iface->needs_reset)
 366                 scx200_acb_reset(iface);
 367
 368         rc = iface->result;
 369
 370         up(&iface->sem);
 371
 372         if (rc == 0 && size == I2C_SMBUS_WORD_DATA && rw == I2C_SMBUS_READ)
 373                 data->word = le16_to_cpu(cur_word);
 374
 375 #ifdef DEBUG
 376         DBG(": transfer done, result: %d", rc);
 377         if (buffer) {
 378                 int i;
 379                 printk(" data:");
 380                 for (i = 0; i < len; ++i)
 381                         printk(" %02x", buffer[i]);
 382         }
 383         printk("\n");
 384 #endif
 385
 386         return rc;
 387 }
 388
 389 static u32 scx200_acb_func(struct i2c_adapter *adapter)
 390 {
 391         return I2C_FUNC_SMBUS_QUICK | I2C_FUNC_SMBUS_BYTE |
 392                I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA |
 393                I2C_FUNC_SMBUS_BLOCK_DATA;
 394 }
 395
 396 /* For now, we only handle combined mode (smbus) */
 397 static struct i2c_algorithm scx200_acb_algorithm = {
 398         .name           = "NatSemi SCx200 ACCESS.bus",
 399         .id             = I2C_ALGO_SMBUS,
 400         .smbus_xfer     = scx200_acb_smbus_xfer,
 401         .functionality  = scx200_acb_func,
 402 };
 403
 404 struct scx200_acb_iface *scx200_acb_list;
 405
 406 int scx200_acb_probe(struct scx200_acb_iface *iface)
 407 {
 408         u8 val;
 409
 410         /* Disable the ACCESS.bus device and Configure the SCL
 411            frequency: 16 clock cycles */
 412         outb(0x70, ACBCTL2);
 413
 414         if (inb(ACBCTL2) != 0x70) {
 415                 DBG("ACBCTL2 readback failed\n");
 416                 return -ENXIO;
 417         }
 418
 419         outb(inb(ACBCTL1) | ACBCTL1_NMINTE, ACBCTL1);
 420
 421         val = inb(ACBCTL1);
 422         if (val) {
 423                 DBG("disabled, but ACBCTL1=0x%02x\n", val);
 424                 return -ENXIO;
 425         }
 426
 427         outb(inb(ACBCTL2) | ACBCTL2_ENABLE, ACBCTL2);
 428
 429         outb(inb(ACBCTL1) | ACBCTL1_NMINTE, ACBCTL1);
 430
 431         val = inb(ACBCTL1);
 432         if ((val & ACBCTL1_NMINTE) != ACBCTL1_NMINTE) {
 433                 DBG("enabled, but NMINTE won't be set, ACBCTL1=0x%02x\n", val);
 434                 return -ENXIO;
 435         }
 436
 437         return 0;
 438 }
 439
 440 static int  __init scx200_acb_create(int base, int index)
 441 {
 442         struct scx200_acb_iface *iface;
 443         struct i2c_adapter *adapter;
 444         int rc = 0;
 445         char description[64];
 446
 447         iface = kmalloc(sizeof(*iface), GFP_KERNEL);
 448         if (!iface) {
 449                 printk(KERN_ERR NAME ": can't allocate memory\n");
 450                 rc = -ENOMEM;
 451                 goto errout;
 452         }
 453
 454         memset(iface, 0, sizeof(*iface));
 455         adapter = &iface->adapter;
 456         i2c_set_adapdata(adapter, iface);
 457         snprintf(adapter->name, I2C_NAME_SIZE, "SCx200 ACB%d", index);
 458         adapter->owner = THIS_MODULE;
 459         adapter->id = I2C_ALGO_SMBUS;
 460         adapter->algo = &scx200_acb_algorithm;
 461
 462         init_MUTEX(&iface->sem);
 463
 464         snprintf(description, sizeof(description), "NatSemi SCx200 ACCESS.bus [%s]", adapter->name);
 465         if (request_region(base, 8, description) == 0) {
 466                 dev_err(&adapter->dev, "can't allocate io 0x%x-0x%x\n",
 467                         base, base + 8-1);
 468                 rc = -EBUSY;
 469                 goto errout;
 470         }
 471         iface->base = base;
 472
 473         rc = scx200_acb_probe(iface);
 474         if (rc) {
 475                 dev_warn(&adapter->dev, "probe failed\n");
 476                 goto errout;
 477         }
 478
 479         scx200_acb_reset(iface);
 480
 481         if (i2c_add_adapter(adapter) < 0) {
 482                 dev_err(&adapter->dev, "failed to register\n");
 483                 rc = -ENODEV;
 484                 goto errout;
 485         }
 486
 487         lock_kernel();
 488         iface->next = scx200_acb_list;
 489         scx200_acb_list = iface;
 490         unlock_kernel();
 491
 492         return 0;
 493
 494  errout:
 495         if (iface) {
 496                 if (iface->base)
 497                         release_region(iface->base, 8);
 498                 kfree(iface);
 499         }
 500         return rc;
 501 }
 502
 503 static int __init scx200_acb_init(void)
 504 {
 505         int i;
 506         int rc;
 507
 508         pr_debug(NAME ": NatSemi SCx200 ACCESS.bus Driver\n");
 509
 510         /* Verify that this really is a SCx200 processor */
 511         if (pci_find_device(PCI_VENDOR_ID_NS,
 512                             PCI_DEVICE_ID_NS_SCx200_BRIDGE,
 513                             NULL) == NULL
 514             && pci_find_device(PCI_VENDOR_ID_NS,
 515                                PCI_DEVICE_ID_NS_SC1100_BRIDGE,
 516                                NULL) == NULL)
 517                 return -ENODEV;
 518
 519         rc = -ENXIO;
 520         for (i = 0; i < MAX_DEVICES; ++i) {
 521                 if (base[i] > 0)
 522                         rc = scx200_acb_create(base[i], i);
 523         }
 524         if (scx200_acb_list)
 525                 return 0;
 526         return rc;
 527 }
 528
 529 static void __exit scx200_acb_cleanup(void)
 530 {
 531         struct scx200_acb_iface *iface;
 532         lock_kernel();
 533         while ((iface = scx200_acb_list) != NULL) {
 534                 scx200_acb_list = iface->next;
 535                 unlock_kernel();
 536
 537                 i2c_del_adapter(&iface->adapter);
 538                 release_region(iface->base, 8);
 539                 kfree(iface);
 540                 lock_kernel();
 541         }
 542         unlock_kernel();
 543 }
 544
 545 module_init(scx200_acb_init);
 546 module_exit(scx200_acb_cleanup);
 547
 548 /*
 549     Local variables:
 550         compile-command: "make -k -C ../.. SUBDIRS=drivers/i2c modules"
 551         c-basic-offset: 8
 552     End:
 553 */
 554