1 /* 2 Copyright (c) 2001,2002 Christer Weinigel <wingel@nano-system.com> 3 4 National Semiconductor SCx200 ACCESS.bus support 5 Also supports the AMD CS5535 and AMD CS5536 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 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 27 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/pci.h> 34 #include <linux/platform_device.h> 35 #include <linux/delay.h> 36 #include <linux/mutex.h> 37 #include <linux/slab.h> 38 #include <linux/io.h> 39 40 #include <linux/scx200.h> 41 42 MODULE_AUTHOR("Christer Weinigel <wingel@nano-system.com>"); 43 MODULE_DESCRIPTION("NatSemi SCx200 ACCESS.bus Driver"); 44 MODULE_ALIAS("platform:cs5535-smb"); 45 MODULE_LICENSE("GPL"); 46 47 #define MAX_DEVICES 4 48 static int base[MAX_DEVICES] = { 0x820, 0x840 }; 49 module_param_array(base, int, NULL, 0); 50 MODULE_PARM_DESC(base, "Base addresses for the ACCESS.bus controllers"); 51 52 #define POLL_TIMEOUT (HZ/5) 53 54 enum scx200_acb_state { 55 state_idle, 56 state_address, 57 state_command, 58 state_repeat_start, 59 state_quick, 60 state_read, 61 state_write, 62 }; 63 64 static const char *scx200_acb_state_name[] = { 65 "idle", 66 "address", 67 "command", 68 "repeat_start", 69 "quick", 70 "read", 71 "write", 72 }; 73 74 /* Physical interface */ 75 struct scx200_acb_iface { 76 struct scx200_acb_iface *next; 77 struct i2c_adapter adapter; 78 unsigned base; 79 struct mutex mutex; 80 81 /* State machine data */ 82 enum scx200_acb_state state; 83 int result; 84 u8 address_byte; 85 u8 command; 86 u8 *ptr; 87 char needs_reset; 88 unsigned len; 89 }; 90 91 /* Register Definitions */ 92 #define ACBSDA (iface->base + 0) 93 #define ACBST (iface->base + 1) 94 #define ACBST_SDAST 0x40 /* SDA Status */ 95 #define ACBST_BER 0x20 96 #define ACBST_NEGACK 0x10 /* Negative Acknowledge */ 97 #define ACBST_STASTR 0x08 /* Stall After Start */ 98 #define ACBST_MASTER 0x02 99 #define ACBCST (iface->base + 2) 100 #define ACBCST_BB 0x02 101 #define ACBCTL1 (iface->base + 3) 102 #define ACBCTL1_STASTRE 0x80 103 #define ACBCTL1_NMINTE 0x40 104 #define ACBCTL1_ACK 0x10 105 #define ACBCTL1_STOP 0x02 106 #define ACBCTL1_START 0x01 107 #define ACBADDR (iface->base + 4) 108 #define ACBCTL2 (iface->base + 5) 109 #define ACBCTL2_ENABLE 0x01 110 111 /************************************************************************/ 112 113 static void scx200_acb_machine(struct scx200_acb_iface *iface, u8 status) 114 { 115 const char *errmsg; 116 117 dev_dbg(&iface->adapter.dev, "state %s, status = 0x%02x\n", 118 scx200_acb_state_name[iface->state], status); 119 120 if (status & ACBST_BER) { 121 errmsg = "bus error"; 122 goto error; 123 } 124 if (!(status & ACBST_MASTER)) { 125 errmsg = "not master"; 126 goto error; 127 } 128 if (status & ACBST_NEGACK) { 129 dev_dbg(&iface->adapter.dev, "negative ack in state %s\n", 130 scx200_acb_state_name[iface->state]); 131 132 iface->state = state_idle; 133 iface->result = -ENXIO; 134 135 outb(inb(ACBCTL1) | ACBCTL1_STOP, ACBCTL1); 136 outb(ACBST_STASTR | ACBST_NEGACK, ACBST); 137 138 /* Reset the status register */ 139 outb(0, ACBST); 140 return; 141 } 142 143 switch (iface->state) { 144 case state_idle: 145 dev_warn(&iface->adapter.dev, "interrupt in idle state\n"); 146 break; 147 148 case state_address: 149 /* Do a pointer write first */ 150 outb(iface->address_byte & ~1, ACBSDA); 151 152 iface->state = state_command; 153 break; 154 155 case state_command: 156 outb(iface->command, ACBSDA); 157 158 if (iface->address_byte & 1) 159 iface->state = state_repeat_start; 160 else 161 iface->state = state_write; 162 break; 163 164 case state_repeat_start: 165 outb(inb(ACBCTL1) | ACBCTL1_START, ACBCTL1); 166 /* fallthrough */ 167 168 case state_quick: 169 if (iface->address_byte & 1) { 170 if (iface->len == 1) 171 outb(inb(ACBCTL1) | ACBCTL1_ACK, ACBCTL1); 172 else 173 outb(inb(ACBCTL1) & ~ACBCTL1_ACK, ACBCTL1); 174 outb(iface->address_byte, ACBSDA); 175 176 iface->state = state_read; 177 } else { 178 outb(iface->address_byte, ACBSDA); 179 180 iface->state = state_write; 181 } 182 break; 183 184 case state_read: 185 /* Set ACK if _next_ byte will be the last one */ 186 if (iface->len == 2) 187 outb(inb(ACBCTL1) | ACBCTL1_ACK, ACBCTL1); 188 else 189 outb(inb(ACBCTL1) & ~ACBCTL1_ACK, ACBCTL1); 190 191 if (iface->len == 1) { 192 iface->result = 0; 193 iface->state = state_idle; 194 outb(inb(ACBCTL1) | ACBCTL1_STOP, ACBCTL1); 195 } 196 197 *iface->ptr++ = inb(ACBSDA); 198 --iface->len; 199 200 break; 201 202 case state_write: 203 if (iface->len == 0) { 204 iface->result = 0; 205 iface->state = state_idle; 206 outb(inb(ACBCTL1) | ACBCTL1_STOP, ACBCTL1); 207 break; 208 } 209 210 outb(*iface->ptr++, ACBSDA); 211 --iface->len; 212 213 break; 214 } 215 216 return; 217 218 error: 219 dev_err(&iface->adapter.dev, 220 "%s in state %s (addr=0x%02x, len=%d, status=0x%02x)\n", errmsg, 221 scx200_acb_state_name[iface->state], iface->address_byte, 222 iface->len, status); 223 224 iface->state = state_idle; 225 iface->result = -EIO; 226 iface->needs_reset = 1; 227 } 228 229 static void scx200_acb_poll(struct scx200_acb_iface *iface) 230 { 231 u8 status; 232 unsigned long timeout; 233 234 timeout = jiffies + POLL_TIMEOUT; 235 while (1) { 236 status = inb(ACBST); 237 238 /* Reset the status register to avoid the hang */ 239 outb(0, ACBST); 240 241 if ((status & (ACBST_SDAST|ACBST_BER|ACBST_NEGACK)) != 0) { 242 scx200_acb_machine(iface, status); 243 return; 244 } 245 if (time_after(jiffies, timeout)) 246 break; 247 cpu_relax(); 248 cond_resched(); 249 } 250 251 dev_err(&iface->adapter.dev, "timeout in state %s\n", 252 scx200_acb_state_name[iface->state]); 253 254 iface->state = state_idle; 255 iface->result = -EIO; 256 iface->needs_reset = 1; 257 } 258 259 static void scx200_acb_reset(struct scx200_acb_iface *iface) 260 { 261 /* Disable the ACCESS.bus device and Configure the SCL 262 frequency: 16 clock cycles */ 263 outb(0x70, ACBCTL2); 264 /* Polling mode */ 265 outb(0, ACBCTL1); 266 /* Disable slave address */ 267 outb(0, ACBADDR); 268 /* Enable the ACCESS.bus device */ 269 outb(inb(ACBCTL2) | ACBCTL2_ENABLE, ACBCTL2); 270 /* Free STALL after START */ 271 outb(inb(ACBCTL1) & ~(ACBCTL1_STASTRE | ACBCTL1_NMINTE), ACBCTL1); 272 /* Send a STOP */ 273 outb(inb(ACBCTL1) | ACBCTL1_STOP, ACBCTL1); 274 /* Clear BER, NEGACK and STASTR bits */ 275 outb(ACBST_BER | ACBST_NEGACK | ACBST_STASTR, ACBST); 276 /* Clear BB bit */ 277 outb(inb(ACBCST) | ACBCST_BB, ACBCST); 278 } 279 280 static s32 scx200_acb_smbus_xfer(struct i2c_adapter *adapter, 281 u16 address, unsigned short flags, 282 char rw, u8 command, int size, 283 union i2c_smbus_data *data) 284 { 285 struct scx200_acb_iface *iface = i2c_get_adapdata(adapter); 286 int len; 287 u8 *buffer; 288 u16 cur_word; 289 int rc; 290 291 switch (size) { 292 case I2C_SMBUS_QUICK: 293 len = 0; 294 buffer = NULL; 295 break; 296 297 case I2C_SMBUS_BYTE: 298 len = 1; 299 buffer = rw ? &data->byte : &command; 300 break; 301 302 case I2C_SMBUS_BYTE_DATA: 303 len = 1; 304 buffer = &data->byte; 305 break; 306 307 case I2C_SMBUS_WORD_DATA: 308 len = 2; 309 cur_word = cpu_to_le16(data->word); 310 buffer = (u8 *)&cur_word; 311 break; 312 313 case I2C_SMBUS_I2C_BLOCK_DATA: 314 len = data->block[0]; 315 if (len == 0 || len > I2C_SMBUS_BLOCK_MAX) 316 return -EINVAL; 317 buffer = &data->block[1]; 318 break; 319 320 default: 321 return -EINVAL; 322 } 323 324 dev_dbg(&adapter->dev, 325 "size=%d, address=0x%x, command=0x%x, len=%d, read=%d\n", 326 size, address, command, len, rw); 327 328 if (!len && rw == I2C_SMBUS_READ) { 329 dev_dbg(&adapter->dev, "zero length read\n"); 330 return -EINVAL; 331 } 332 333 mutex_lock(&iface->mutex); 334 335 iface->address_byte = (address << 1) | rw; 336 iface->command = command; 337 iface->ptr = buffer; 338 iface->len = len; 339 iface->result = -EINVAL; 340 iface->needs_reset = 0; 341 342 outb(inb(ACBCTL1) | ACBCTL1_START, ACBCTL1); 343 344 if (size == I2C_SMBUS_QUICK || size == I2C_SMBUS_BYTE) 345 iface->state = state_quick; 346 else 347 iface->state = state_address; 348 349 while (iface->state != state_idle) 350 scx200_acb_poll(iface); 351 352 if (iface->needs_reset) 353 scx200_acb_reset(iface); 354 355 rc = iface->result; 356 357 mutex_unlock(&iface->mutex); 358 359 if (rc == 0 && size == I2C_SMBUS_WORD_DATA && rw == I2C_SMBUS_READ) 360 data->word = le16_to_cpu(cur_word); 361 362 #ifdef DEBUG 363 dev_dbg(&adapter->dev, "transfer done, result: %d", rc); 364 if (buffer) { 365 int i; 366 printk(" data:"); 367 for (i = 0; i < len; ++i) 368 printk(" %02x", buffer[i]); 369 } 370 printk("\n"); 371 #endif 372 373 return rc; 374 } 375 376 static u32 scx200_acb_func(struct i2c_adapter *adapter) 377 { 378 return I2C_FUNC_SMBUS_QUICK | I2C_FUNC_SMBUS_BYTE | 379 I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA | 380 I2C_FUNC_SMBUS_I2C_BLOCK; 381 } 382 383 /* For now, we only handle combined mode (smbus) */ 384 static const struct i2c_algorithm scx200_acb_algorithm = { 385 .smbus_xfer = scx200_acb_smbus_xfer, 386 .functionality = scx200_acb_func, 387 }; 388 389 static struct scx200_acb_iface *scx200_acb_list; 390 static DEFINE_MUTEX(scx200_acb_list_mutex); 391 392 static int scx200_acb_probe(struct scx200_acb_iface *iface) 393 { 394 u8 val; 395 396 /* Disable the ACCESS.bus device and Configure the SCL 397 frequency: 16 clock cycles */ 398 outb(0x70, ACBCTL2); 399 400 if (inb(ACBCTL2) != 0x70) { 401 pr_debug("ACBCTL2 readback failed\n"); 402 return -ENXIO; 403 } 404 405 outb(inb(ACBCTL1) | ACBCTL1_NMINTE, ACBCTL1); 406 407 val = inb(ACBCTL1); 408 if (val) { 409 pr_debug("disabled, but ACBCTL1=0x%02x\n", val); 410 return -ENXIO; 411 } 412 413 outb(inb(ACBCTL2) | ACBCTL2_ENABLE, ACBCTL2); 414 415 outb(inb(ACBCTL1) | ACBCTL1_NMINTE, ACBCTL1); 416 417 val = inb(ACBCTL1); 418 if ((val & ACBCTL1_NMINTE) != ACBCTL1_NMINTE) { 419 pr_debug("enabled, but NMINTE won't be set, ACBCTL1=0x%02x\n", 420 val); 421 return -ENXIO; 422 } 423 424 return 0; 425 } 426 427 static struct scx200_acb_iface *scx200_create_iface(const char *text, 428 struct device *dev, int index) 429 { 430 struct scx200_acb_iface *iface; 431 struct i2c_adapter *adapter; 432 433 iface = kzalloc(sizeof(*iface), GFP_KERNEL); 434 if (!iface) { 435 pr_err("can't allocate memory\n"); 436 return NULL; 437 } 438 439 adapter = &iface->adapter; 440 i2c_set_adapdata(adapter, iface); 441 snprintf(adapter->name, sizeof(adapter->name), "%s ACB%d", text, index); 442 adapter->owner = THIS_MODULE; 443 adapter->algo = &scx200_acb_algorithm; 444 adapter->class = I2C_CLASS_HWMON | I2C_CLASS_SPD; 445 adapter->dev.parent = dev; 446 447 mutex_init(&iface->mutex); 448 449 return iface; 450 } 451 452 static int scx200_acb_create(struct scx200_acb_iface *iface) 453 { 454 struct i2c_adapter *adapter; 455 int rc; 456 457 adapter = &iface->adapter; 458 459 rc = scx200_acb_probe(iface); 460 if (rc) { 461 pr_warn("probe failed\n"); 462 return rc; 463 } 464 465 scx200_acb_reset(iface); 466 467 if (i2c_add_adapter(adapter) < 0) { 468 pr_err("failed to register\n"); 469 return -ENODEV; 470 } 471 472 if (!adapter->dev.parent) { 473 /* If there's no dev, we're tracking (ISA) ifaces manually */ 474 mutex_lock(&scx200_acb_list_mutex); 475 iface->next = scx200_acb_list; 476 scx200_acb_list = iface; 477 mutex_unlock(&scx200_acb_list_mutex); 478 } 479 480 return 0; 481 } 482 483 static struct scx200_acb_iface *scx200_create_dev(const char *text, 484 unsigned long base, int index, struct device *dev) 485 { 486 struct scx200_acb_iface *iface; 487 int rc; 488 489 iface = scx200_create_iface(text, dev, index); 490 491 if (iface == NULL) 492 return NULL; 493 494 if (!request_region(base, 8, iface->adapter.name)) { 495 pr_err("can't allocate io 0x%lx-0x%lx\n", base, base + 8 - 1); 496 goto errout_free; 497 } 498 499 iface->base = base; 500 rc = scx200_acb_create(iface); 501 502 if (rc == 0) 503 return iface; 504 505 release_region(base, 8); 506 errout_free: 507 kfree(iface); 508 return NULL; 509 } 510 511 static int scx200_probe(struct platform_device *pdev) 512 { 513 struct scx200_acb_iface *iface; 514 struct resource *res; 515 516 res = platform_get_resource(pdev, IORESOURCE_IO, 0); 517 if (!res) { 518 dev_err(&pdev->dev, "can't fetch device resource info\n"); 519 return -ENODEV; 520 } 521 522 iface = scx200_create_dev("CS5535", res->start, 0, &pdev->dev); 523 if (!iface) 524 return -EIO; 525 526 dev_info(&pdev->dev, "SCx200 device '%s' registered\n", 527 iface->adapter.name); 528 platform_set_drvdata(pdev, iface); 529 530 return 0; 531 } 532 533 static void scx200_cleanup_iface(struct scx200_acb_iface *iface) 534 { 535 i2c_del_adapter(&iface->adapter); 536 release_region(iface->base, 8); 537 kfree(iface); 538 } 539 540 static int scx200_remove(struct platform_device *pdev) 541 { 542 struct scx200_acb_iface *iface; 543 544 iface = platform_get_drvdata(pdev); 545 platform_set_drvdata(pdev, NULL); 546 scx200_cleanup_iface(iface); 547 548 return 0; 549 } 550 551 static struct platform_driver scx200_pci_driver = { 552 .driver = { 553 .name = "cs5535-smb", 554 .owner = THIS_MODULE, 555 }, 556 .probe = scx200_probe, 557 .remove = scx200_remove, 558 }; 559 560 static DEFINE_PCI_DEVICE_TABLE(scx200_isa) = { 561 { PCI_DEVICE(PCI_VENDOR_ID_NS, PCI_DEVICE_ID_NS_SCx200_BRIDGE) }, 562 { PCI_DEVICE(PCI_VENDOR_ID_NS, PCI_DEVICE_ID_NS_SC1100_BRIDGE) }, 563 { 0, } 564 }; 565 566 static __init void scx200_scan_isa(void) 567 { 568 int i; 569 570 if (!pci_dev_present(scx200_isa)) 571 return; 572 573 for (i = 0; i < MAX_DEVICES; ++i) { 574 if (base[i] == 0) 575 continue; 576 577 /* XXX: should we care about failures? */ 578 scx200_create_dev("SCx200", base[i], i, NULL); 579 } 580 } 581 582 static int __init scx200_acb_init(void) 583 { 584 pr_debug("NatSemi SCx200 ACCESS.bus Driver\n"); 585 586 /* First scan for ISA-based devices */ 587 scx200_scan_isa(); /* XXX: should we care about errors? */ 588 589 /* If at least one bus was created, init must succeed */ 590 if (scx200_acb_list) 591 return 0; 592 593 /* No ISA devices; register the platform driver for PCI-based devices */ 594 return platform_driver_register(&scx200_pci_driver); 595 } 596 597 static void __exit scx200_acb_cleanup(void) 598 { 599 struct scx200_acb_iface *iface; 600 601 platform_driver_unregister(&scx200_pci_driver); 602 603 mutex_lock(&scx200_acb_list_mutex); 604 while ((iface = scx200_acb_list) != NULL) { 605 scx200_acb_list = iface->next; 606 mutex_unlock(&scx200_acb_list_mutex); 607 608 scx200_cleanup_iface(iface); 609 610 mutex_lock(&scx200_acb_list_mutex); 611 } 612 mutex_unlock(&scx200_acb_list_mutex); 613 } 614 615 module_init(scx200_acb_init); 616 module_exit(scx200_acb_cleanup); 617