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 | |
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(value: 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(value: iface->address_byte & ~1, ACBSDA); |
139 | |
140 | iface->state = state_command; |
141 | break; |
142 | |
143 | case state_command: |
144 | outb(value: 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(value: iface->address_byte, ACBSDA); |
163 | |
164 | iface->state = state_read; |
165 | } else { |
166 | outb(value: 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(value: *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 | |
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(value: 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 | |
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(value: 0x70, ACBCTL2); |
252 | /* Polling mode */ |
253 | outb(value: 0, ACBCTL1); |
254 | /* Disable slave address */ |
255 | outb(value: 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 | |
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(adap: 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(lock: &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 | |
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 | |
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(value: 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 | |
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(size: sizeof(*iface), GFP_KERNEL); |
422 | if (!iface) |
423 | return NULL; |
424 | |
425 | adapter = &iface->adapter; |
426 | i2c_set_adapdata(adap: adapter, data: iface); |
427 | snprintf(buf: adapter->name, size: sizeof(adapter->name), fmt: "%s ACB%d" , text, index); |
428 | adapter->owner = THIS_MODULE; |
429 | adapter->algo = &scx200_acb_algorithm; |
430 | adapter->class = I2C_CLASS_HWMON; |
431 | adapter->dev.parent = dev; |
432 | |
433 | mutex_init(&iface->mutex); |
434 | |
435 | return iface; |
436 | } |
437 | |
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(adap: 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(lock: &scx200_acb_list_mutex); |
464 | } |
465 | |
466 | return 0; |
467 | } |
468 | |
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(objp: iface); |
494 | return NULL; |
495 | } |
496 | |
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(text: "CS5535" , base: res->start, index: 0, dev: &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, data: iface); |
515 | |
516 | return 0; |
517 | } |
518 | |
519 | static void scx200_cleanup_iface(struct scx200_acb_iface *iface) |
520 | { |
521 | i2c_del_adapter(adap: &iface->adapter); |
522 | release_region(iface->base, 8); |
523 | kfree(objp: iface); |
524 | } |
525 | |
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 | |
548 | static __init void scx200_scan_isa(void) |
549 | { |
550 | int i; |
551 | |
552 | if (!pci_dev_present(ids: 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(text: "SCx200" , base: base[i], index: i, NULL); |
561 | } |
562 | } |
563 | |
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 | |
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(lock: &scx200_acb_list_mutex); |
589 | |
590 | scx200_cleanup_iface(iface); |
591 | |
592 | mutex_lock(&scx200_acb_list_mutex); |
593 | } |
594 | mutex_unlock(lock: &scx200_acb_list_mutex); |
595 | } |
596 | |
597 | module_init(scx200_acb_init); |
598 | module_exit(scx200_acb_cleanup); |
599 | |