1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 Copyright (c) 2001,2002 Christer Weinigel <wingel@nano-system.com> 4 5 National Semiconductor SCx200 ACCESS.bus support 6 Also supports the AMD CS5535 and AMD CS5536 7 8 Based on i2c-keywest.c which is: 9 Copyright (c) 2001 Benjamin Herrenschmidt <benh@kernel.crashing.org> 10 Copyright (c) 2000 Philip Edelbrock <phil@stimpy.netroedge.com> 11 12 */ 13 14 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 15 16 #include <linux/module.h> 17 #include <linux/errno.h> 18 #include <linux/kernel.h> 19 #include <linux/init.h> 20 #include <linux/i2c.h> 21 #include <linux/pci.h> 22 #include <linux/platform_device.h> 23 #include <linux/delay.h> 24 #include <linux/mutex.h> 25 #include <linux/slab.h> 26 #include <linux/io.h> 27 28 #include <linux/scx200.h> 29 30 MODULE_AUTHOR("Christer Weinigel <wingel@nano-system.com>"); 31 MODULE_DESCRIPTION("NatSemi SCx200 ACCESS.bus Driver"); 32 MODULE_ALIAS("platform:cs5535-smb"); 33 MODULE_LICENSE("GPL"); 34 35 #define MAX_DEVICES 4 36 static int base[MAX_DEVICES] = { 0x820, 0x840 }; 37 module_param_hw_array(base, int, ioport, NULL, 0); 38 MODULE_PARM_DESC(base, "Base addresses for the ACCESS.bus controllers"); 39 40 #define POLL_TIMEOUT (HZ/5) 41 42 enum scx200_acb_state { 43 state_idle, 44 state_address, 45 state_command, 46 state_repeat_start, 47 state_quick, 48 state_read, 49 state_write, 50 }; 51 52 static const char *scx200_acb_state_name[] = { 53 "idle", 54 "address", 55 "command", 56 "repeat_start", 57 "quick", 58 "read", 59 "write", 60 }; 61 62 /* Physical interface */ 63 struct scx200_acb_iface { 64 struct scx200_acb_iface *next; 65 struct i2c_adapter adapter; 66 unsigned base; 67 struct mutex mutex; 68 69 /* State machine data */ 70 enum scx200_acb_state state; 71 int result; 72 u8 address_byte; 73 u8 command; 74 u8 *ptr; 75 char needs_reset; 76 unsigned len; 77 }; 78 79 /* Register Definitions */ 80 #define ACBSDA (iface->base + 0) 81 #define ACBST (iface->base + 1) 82 #define ACBST_SDAST 0x40 /* SDA Status */ 83 #define ACBST_BER 0x20 84 #define ACBST_NEGACK 0x10 /* Negative Acknowledge */ 85 #define ACBST_STASTR 0x08 /* Stall After Start */ 86 #define ACBST_MASTER 0x02 87 #define ACBCST (iface->base + 2) 88 #define ACBCST_BB 0x02 89 #define ACBCTL1 (iface->base + 3) 90 #define ACBCTL1_STASTRE 0x80 91 #define ACBCTL1_NMINTE 0x40 92 #define ACBCTL1_ACK 0x10 93 #define ACBCTL1_STOP 0x02 94 #define ACBCTL1_START 0x01 95 #define ACBADDR (iface->base + 4) 96 #define ACBCTL2 (iface->base + 5) 97 #define ACBCTL2_ENABLE 0x01 98 99 /************************************************************************/ 100 scx200_acb_machine(struct scx200_acb_iface * iface,u8 status)101 static void scx200_acb_machine(struct scx200_acb_iface *iface, u8 status) 102 { 103 const char *errmsg; 104 105 dev_dbg(&iface->adapter.dev, "state %s, status = 0x%02x\n", 106 scx200_acb_state_name[iface->state], status); 107 108 if (status & ACBST_BER) { 109 errmsg = "bus error"; 110 goto error; 111 } 112 if (!(status & ACBST_MASTER)) { 113 errmsg = "not master"; 114 goto error; 115 } 116 if (status & ACBST_NEGACK) { 117 dev_dbg(&iface->adapter.dev, "negative ack in state %s\n", 118 scx200_acb_state_name[iface->state]); 119 120 iface->state = state_idle; 121 iface->result = -ENXIO; 122 123 outb(inb(ACBCTL1) | ACBCTL1_STOP, ACBCTL1); 124 outb(ACBST_STASTR | ACBST_NEGACK, ACBST); 125 126 /* Reset the status register */ 127 outb(0, ACBST); 128 return; 129 } 130 131 switch (iface->state) { 132 case state_idle: 133 dev_warn(&iface->adapter.dev, "interrupt in idle state\n"); 134 break; 135 136 case state_address: 137 /* Do a pointer write first */ 138 outb(iface->address_byte & ~1, ACBSDA); 139 140 iface->state = state_command; 141 break; 142 143 case state_command: 144 outb(iface->command, ACBSDA); 145 146 if (iface->address_byte & 1) 147 iface->state = state_repeat_start; 148 else 149 iface->state = state_write; 150 break; 151 152 case state_repeat_start: 153 outb(inb(ACBCTL1) | ACBCTL1_START, ACBCTL1); 154 fallthrough; 155 156 case state_quick: 157 if (iface->address_byte & 1) { 158 if (iface->len == 1) 159 outb(inb(ACBCTL1) | ACBCTL1_ACK, ACBCTL1); 160 else 161 outb(inb(ACBCTL1) & ~ACBCTL1_ACK, ACBCTL1); 162 outb(iface->address_byte, ACBSDA); 163 164 iface->state = state_read; 165 } else { 166 outb(iface->address_byte, ACBSDA); 167 168 iface->state = state_write; 169 } 170 break; 171 172 case state_read: 173 /* Set ACK if _next_ byte will be the last one */ 174 if (iface->len == 2) 175 outb(inb(ACBCTL1) | ACBCTL1_ACK, ACBCTL1); 176 else 177 outb(inb(ACBCTL1) & ~ACBCTL1_ACK, ACBCTL1); 178 179 if (iface->len == 1) { 180 iface->result = 0; 181 iface->state = state_idle; 182 outb(inb(ACBCTL1) | ACBCTL1_STOP, ACBCTL1); 183 } 184 185 *iface->ptr++ = inb(ACBSDA); 186 --iface->len; 187 188 break; 189 190 case state_write: 191 if (iface->len == 0) { 192 iface->result = 0; 193 iface->state = state_idle; 194 outb(inb(ACBCTL1) | ACBCTL1_STOP, ACBCTL1); 195 break; 196 } 197 198 outb(*iface->ptr++, ACBSDA); 199 --iface->len; 200 201 break; 202 } 203 204 return; 205 206 error: 207 dev_err(&iface->adapter.dev, 208 "%s in state %s (addr=0x%02x, len=%d, status=0x%02x)\n", errmsg, 209 scx200_acb_state_name[iface->state], iface->address_byte, 210 iface->len, status); 211 212 iface->state = state_idle; 213 iface->result = -EIO; 214 iface->needs_reset = 1; 215 } 216 scx200_acb_poll(struct scx200_acb_iface * iface)217 static void scx200_acb_poll(struct scx200_acb_iface *iface) 218 { 219 u8 status; 220 unsigned long timeout; 221 222 timeout = jiffies + POLL_TIMEOUT; 223 while (1) { 224 status = inb(ACBST); 225 226 /* Reset the status register to avoid the hang */ 227 outb(0, ACBST); 228 229 if ((status & (ACBST_SDAST|ACBST_BER|ACBST_NEGACK)) != 0) { 230 scx200_acb_machine(iface, status); 231 return; 232 } 233 if (time_after(jiffies, timeout)) 234 break; 235 cpu_relax(); 236 cond_resched(); 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 scx200_acb_reset(struct scx200_acb_iface * iface)247 static void scx200_acb_reset(struct scx200_acb_iface *iface) 248 { 249 /* Disable the ACCESS.bus device and Configure the SCL 250 frequency: 16 clock cycles */ 251 outb(0x70, ACBCTL2); 252 /* Polling mode */ 253 outb(0, ACBCTL1); 254 /* Disable slave address */ 255 outb(0, ACBADDR); 256 /* Enable the ACCESS.bus device */ 257 outb(inb(ACBCTL2) | ACBCTL2_ENABLE, ACBCTL2); 258 /* Free STALL after START */ 259 outb(inb(ACBCTL1) & ~(ACBCTL1_STASTRE | ACBCTL1_NMINTE), ACBCTL1); 260 /* Send a STOP */ 261 outb(inb(ACBCTL1) | ACBCTL1_STOP, ACBCTL1); 262 /* Clear BER, NEGACK and STASTR bits */ 263 outb(ACBST_BER | ACBST_NEGACK | ACBST_STASTR, ACBST); 264 /* Clear BB bit */ 265 outb(inb(ACBCST) | ACBCST_BB, ACBCST); 266 } 267 scx200_acb_smbus_xfer(struct i2c_adapter * adapter,u16 address,unsigned short flags,char rw,u8 command,int size,union i2c_smbus_data * data)268 static s32 scx200_acb_smbus_xfer(struct i2c_adapter *adapter, 269 u16 address, unsigned short flags, 270 char rw, u8 command, int size, 271 union i2c_smbus_data *data) 272 { 273 struct scx200_acb_iface *iface = i2c_get_adapdata(adapter); 274 int len; 275 u8 *buffer; 276 u16 cur_word; 277 int rc; 278 279 switch (size) { 280 case I2C_SMBUS_QUICK: 281 len = 0; 282 buffer = NULL; 283 break; 284 285 case I2C_SMBUS_BYTE: 286 len = 1; 287 buffer = rw ? &data->byte : &command; 288 break; 289 290 case I2C_SMBUS_BYTE_DATA: 291 len = 1; 292 buffer = &data->byte; 293 break; 294 295 case I2C_SMBUS_WORD_DATA: 296 len = 2; 297 cur_word = cpu_to_le16(data->word); 298 buffer = (u8 *)&cur_word; 299 break; 300 301 case I2C_SMBUS_I2C_BLOCK_DATA: 302 len = data->block[0]; 303 if (len == 0 || len > I2C_SMBUS_BLOCK_MAX) 304 return -EINVAL; 305 buffer = &data->block[1]; 306 break; 307 308 default: 309 return -EINVAL; 310 } 311 312 dev_dbg(&adapter->dev, 313 "size=%d, address=0x%x, command=0x%x, len=%d, read=%d\n", 314 size, address, command, len, rw); 315 316 if (!len && rw == I2C_SMBUS_READ) { 317 dev_dbg(&adapter->dev, "zero length read\n"); 318 return -EINVAL; 319 } 320 321 mutex_lock(&iface->mutex); 322 323 iface->address_byte = (address << 1) | rw; 324 iface->command = command; 325 iface->ptr = buffer; 326 iface->len = len; 327 iface->result = -EINVAL; 328 iface->needs_reset = 0; 329 330 outb(inb(ACBCTL1) | ACBCTL1_START, ACBCTL1); 331 332 if (size == I2C_SMBUS_QUICK || size == I2C_SMBUS_BYTE) 333 iface->state = state_quick; 334 else 335 iface->state = state_address; 336 337 while (iface->state != state_idle) 338 scx200_acb_poll(iface); 339 340 if (iface->needs_reset) 341 scx200_acb_reset(iface); 342 343 rc = iface->result; 344 345 mutex_unlock(&iface->mutex); 346 347 if (rc == 0 && size == I2C_SMBUS_WORD_DATA && rw == I2C_SMBUS_READ) 348 data->word = le16_to_cpu(cur_word); 349 350 #ifdef DEBUG 351 dev_dbg(&adapter->dev, "transfer done, result: %d", rc); 352 if (buffer) { 353 int i; 354 printk(" data:"); 355 for (i = 0; i < len; ++i) 356 printk(" %02x", buffer[i]); 357 } 358 printk("\n"); 359 #endif 360 361 return rc; 362 } 363 scx200_acb_func(struct i2c_adapter * adapter)364 static u32 scx200_acb_func(struct i2c_adapter *adapter) 365 { 366 return I2C_FUNC_SMBUS_QUICK | I2C_FUNC_SMBUS_BYTE | 367 I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA | 368 I2C_FUNC_SMBUS_I2C_BLOCK; 369 } 370 371 /* For now, we only handle combined mode (smbus) */ 372 static const struct i2c_algorithm scx200_acb_algorithm = { 373 .smbus_xfer = scx200_acb_smbus_xfer, 374 .functionality = scx200_acb_func, 375 }; 376 377 static struct scx200_acb_iface *scx200_acb_list; 378 static DEFINE_MUTEX(scx200_acb_list_mutex); 379 scx200_acb_probe(struct scx200_acb_iface * iface)380 static int scx200_acb_probe(struct scx200_acb_iface *iface) 381 { 382 u8 val; 383 384 /* Disable the ACCESS.bus device and Configure the SCL 385 frequency: 16 clock cycles */ 386 outb(0x70, ACBCTL2); 387 388 if (inb(ACBCTL2) != 0x70) { 389 pr_debug("ACBCTL2 readback failed\n"); 390 return -ENXIO; 391 } 392 393 outb(inb(ACBCTL1) | ACBCTL1_NMINTE, ACBCTL1); 394 395 val = inb(ACBCTL1); 396 if (val) { 397 pr_debug("disabled, but ACBCTL1=0x%02x\n", val); 398 return -ENXIO; 399 } 400 401 outb(inb(ACBCTL2) | ACBCTL2_ENABLE, ACBCTL2); 402 403 outb(inb(ACBCTL1) | ACBCTL1_NMINTE, ACBCTL1); 404 405 val = inb(ACBCTL1); 406 if ((val & ACBCTL1_NMINTE) != ACBCTL1_NMINTE) { 407 pr_debug("enabled, but NMINTE won't be set, ACBCTL1=0x%02x\n", 408 val); 409 return -ENXIO; 410 } 411 412 return 0; 413 } 414 scx200_create_iface(const char * text,struct device * dev,int index)415 static struct scx200_acb_iface *scx200_create_iface(const char *text, 416 struct device *dev, int index) 417 { 418 struct scx200_acb_iface *iface; 419 struct i2c_adapter *adapter; 420 421 iface = kzalloc(sizeof(*iface), GFP_KERNEL); 422 if (!iface) 423 return NULL; 424 425 adapter = &iface->adapter; 426 i2c_set_adapdata(adapter, iface); 427 snprintf(adapter->name, sizeof(adapter->name), "%s ACB%d", text, index); 428 adapter->owner = THIS_MODULE; 429 adapter->algo = &scx200_acb_algorithm; 430 adapter->class = I2C_CLASS_HWMON | I2C_CLASS_SPD; 431 adapter->dev.parent = dev; 432 433 mutex_init(&iface->mutex); 434 435 return iface; 436 } 437 scx200_acb_create(struct scx200_acb_iface * iface)438 static int scx200_acb_create(struct scx200_acb_iface *iface) 439 { 440 struct i2c_adapter *adapter; 441 int rc; 442 443 adapter = &iface->adapter; 444 445 rc = scx200_acb_probe(iface); 446 if (rc) { 447 pr_warn("probe failed\n"); 448 return rc; 449 } 450 451 scx200_acb_reset(iface); 452 453 if (i2c_add_adapter(adapter) < 0) { 454 pr_err("failed to register\n"); 455 return -ENODEV; 456 } 457 458 if (!adapter->dev.parent) { 459 /* If there's no dev, we're tracking (ISA) ifaces manually */ 460 mutex_lock(&scx200_acb_list_mutex); 461 iface->next = scx200_acb_list; 462 scx200_acb_list = iface; 463 mutex_unlock(&scx200_acb_list_mutex); 464 } 465 466 return 0; 467 } 468 scx200_create_dev(const char * text,unsigned long base,int index,struct device * dev)469 static struct scx200_acb_iface *scx200_create_dev(const char *text, 470 unsigned long base, int index, struct device *dev) 471 { 472 struct scx200_acb_iface *iface; 473 int rc; 474 475 iface = scx200_create_iface(text, dev, index); 476 477 if (iface == NULL) 478 return NULL; 479 480 if (!request_region(base, 8, iface->adapter.name)) { 481 pr_err("can't allocate io 0x%lx-0x%lx\n", base, base + 8 - 1); 482 goto errout_free; 483 } 484 485 iface->base = base; 486 rc = scx200_acb_create(iface); 487 488 if (rc == 0) 489 return iface; 490 491 release_region(base, 8); 492 errout_free: 493 kfree(iface); 494 return NULL; 495 } 496 scx200_probe(struct platform_device * pdev)497 static int scx200_probe(struct platform_device *pdev) 498 { 499 struct scx200_acb_iface *iface; 500 struct resource *res; 501 502 res = platform_get_resource(pdev, IORESOURCE_IO, 0); 503 if (!res) { 504 dev_err(&pdev->dev, "can't fetch device resource info\n"); 505 return -ENODEV; 506 } 507 508 iface = scx200_create_dev("CS5535", res->start, 0, &pdev->dev); 509 if (!iface) 510 return -EIO; 511 512 dev_info(&pdev->dev, "SCx200 device '%s' registered\n", 513 iface->adapter.name); 514 platform_set_drvdata(pdev, iface); 515 516 return 0; 517 } 518 scx200_cleanup_iface(struct scx200_acb_iface * iface)519 static void scx200_cleanup_iface(struct scx200_acb_iface *iface) 520 { 521 i2c_del_adapter(&iface->adapter); 522 release_region(iface->base, 8); 523 kfree(iface); 524 } 525 scx200_remove(struct platform_device * pdev)526 static void scx200_remove(struct platform_device *pdev) 527 { 528 struct scx200_acb_iface *iface; 529 530 iface = platform_get_drvdata(pdev); 531 scx200_cleanup_iface(iface); 532 } 533 534 static struct platform_driver scx200_pci_driver = { 535 .driver = { 536 .name = "cs5535-smb", 537 }, 538 .probe = scx200_probe, 539 .remove_new = scx200_remove, 540 }; 541 542 static const struct pci_device_id scx200_isa[] = { 543 { PCI_DEVICE(PCI_VENDOR_ID_NS, PCI_DEVICE_ID_NS_SCx200_BRIDGE) }, 544 { PCI_DEVICE(PCI_VENDOR_ID_NS, PCI_DEVICE_ID_NS_SC1100_BRIDGE) }, 545 { 0, } 546 }; 547 scx200_scan_isa(void)548 static __init void scx200_scan_isa(void) 549 { 550 int i; 551 552 if (!pci_dev_present(scx200_isa)) 553 return; 554 555 for (i = 0; i < MAX_DEVICES; ++i) { 556 if (base[i] == 0) 557 continue; 558 559 /* XXX: should we care about failures? */ 560 scx200_create_dev("SCx200", base[i], i, NULL); 561 } 562 } 563 scx200_acb_init(void)564 static int __init scx200_acb_init(void) 565 { 566 pr_debug("NatSemi SCx200 ACCESS.bus Driver\n"); 567 568 /* First scan for ISA-based devices */ 569 scx200_scan_isa(); /* XXX: should we care about errors? */ 570 571 /* If at least one bus was created, init must succeed */ 572 if (scx200_acb_list) 573 return 0; 574 575 /* No ISA devices; register the platform driver for PCI-based devices */ 576 return platform_driver_register(&scx200_pci_driver); 577 } 578 scx200_acb_cleanup(void)579 static void __exit scx200_acb_cleanup(void) 580 { 581 struct scx200_acb_iface *iface; 582 583 platform_driver_unregister(&scx200_pci_driver); 584 585 mutex_lock(&scx200_acb_list_mutex); 586 while ((iface = scx200_acb_list) != NULL) { 587 scx200_acb_list = iface->next; 588 mutex_unlock(&scx200_acb_list_mutex); 589 590 scx200_cleanup_iface(iface); 591 592 mutex_lock(&scx200_acb_list_mutex); 593 } 594 mutex_unlock(&scx200_acb_list_mutex); 595 } 596 597 module_init(scx200_acb_init); 598 module_exit(scx200_acb_cleanup); 599