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 */ 557 558