treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 157
[sfrench/cifs-2.6.git] / drivers / i2c / busses / scx200_acb.c
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(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
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
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
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
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(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(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
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
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
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
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
526 static int 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         return 0;
534 }
535
536 static struct platform_driver scx200_pci_driver = {
537         .driver = {
538                 .name = "cs5535-smb",
539         },
540         .probe = scx200_probe,
541         .remove = scx200_remove,
542 };
543
544 static const struct pci_device_id scx200_isa[] = {
545         { PCI_DEVICE(PCI_VENDOR_ID_NS, PCI_DEVICE_ID_NS_SCx200_BRIDGE) },
546         { PCI_DEVICE(PCI_VENDOR_ID_NS, PCI_DEVICE_ID_NS_SC1100_BRIDGE) },
547         { 0, }
548 };
549
550 static __init void scx200_scan_isa(void)
551 {
552         int i;
553
554         if (!pci_dev_present(scx200_isa))
555                 return;
556
557         for (i = 0; i < MAX_DEVICES; ++i) {
558                 if (base[i] == 0)
559                         continue;
560
561                 /* XXX: should we care about failures? */
562                 scx200_create_dev("SCx200", base[i], i, NULL);
563         }
564 }
565
566 static int __init scx200_acb_init(void)
567 {
568         pr_debug("NatSemi SCx200 ACCESS.bus Driver\n");
569
570         /* First scan for ISA-based devices */
571         scx200_scan_isa();      /* XXX: should we care about errors? */
572
573         /* If at least one bus was created, init must succeed */
574         if (scx200_acb_list)
575                 return 0;
576
577         /* No ISA devices; register the platform driver for PCI-based devices */
578         return platform_driver_register(&scx200_pci_driver);
579 }
580
581 static void __exit scx200_acb_cleanup(void)
582 {
583         struct scx200_acb_iface *iface;
584
585         platform_driver_unregister(&scx200_pci_driver);
586
587         mutex_lock(&scx200_acb_list_mutex);
588         while ((iface = scx200_acb_list) != NULL) {
589                 scx200_acb_list = iface->next;
590                 mutex_unlock(&scx200_acb_list_mutex);
591
592                 scx200_cleanup_iface(iface);
593
594                 mutex_lock(&scx200_acb_list_mutex);
595         }
596         mutex_unlock(&scx200_acb_list_mutex);
597 }
598
599 module_init(scx200_acb_init);
600 module_exit(scx200_acb_cleanup);