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Linux/drivers/i2c/busses/scx200_acb.c

  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 
 22 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 23 
 24 #include <linux/module.h>
 25 #include <linux/errno.h>
 26 #include <linux/kernel.h>
 27 #include <linux/init.h>
 28 #include <linux/i2c.h>
 29 #include <linux/pci.h>
 30 #include <linux/platform_device.h>
 31 #include <linux/delay.h>
 32 #include <linux/mutex.h>
 33 #include <linux/slab.h>
 34 #include <linux/io.h>
 35 
 36 #include <linux/scx200.h>
 37 
 38 MODULE_AUTHOR("Christer Weinigel <wingel@nano-system.com>");
 39 MODULE_DESCRIPTION("NatSemi SCx200 ACCESS.bus Driver");
 40 MODULE_ALIAS("platform:cs5535-smb");
 41 MODULE_LICENSE("GPL");
 42 
 43 #define MAX_DEVICES 4
 44 static int base[MAX_DEVICES] = { 0x820, 0x840 };
 45 module_param_array(base, int, NULL, 0);
 46 MODULE_PARM_DESC(base, "Base addresses for the ACCESS.bus controllers");
 47 
 48 #define POLL_TIMEOUT    (HZ/5)
 49 
 50 enum scx200_acb_state {
 51         state_idle,
 52         state_address,
 53         state_command,
 54         state_repeat_start,
 55         state_quick,
 56         state_read,
 57         state_write,
 58 };
 59 
 60 static const char *scx200_acb_state_name[] = {
 61         "idle",
 62         "address",
 63         "command",
 64         "repeat_start",
 65         "quick",
 66         "read",
 67         "write",
 68 };
 69 
 70 /* Physical interface */
 71 struct scx200_acb_iface {
 72         struct scx200_acb_iface *next;
 73         struct i2c_adapter adapter;
 74         unsigned base;
 75         struct mutex mutex;
 76 
 77         /* State machine data */
 78         enum scx200_acb_state state;
 79         int result;
 80         u8 address_byte;
 81         u8 command;
 82         u8 *ptr;
 83         char needs_reset;
 84         unsigned len;
 85 };
 86 
 87 /* Register Definitions */
 88 #define ACBSDA          (iface->base + 0)
 89 #define ACBST           (iface->base + 1)
 90 #define    ACBST_SDAST          0x40 /* SDA Status */
 91 #define    ACBST_BER            0x20
 92 #define    ACBST_NEGACK         0x10 /* Negative Acknowledge */
 93 #define    ACBST_STASTR         0x08 /* Stall After Start */
 94 #define    ACBST_MASTER         0x02
 95 #define ACBCST          (iface->base + 2)
 96 #define    ACBCST_BB            0x02
 97 #define ACBCTL1         (iface->base + 3)
 98 #define    ACBCTL1_STASTRE      0x80
 99 #define    ACBCTL1_NMINTE       0x40
100 #define    ACBCTL1_ACK          0x10
101 #define    ACBCTL1_STOP         0x02
102 #define    ACBCTL1_START        0x01
103 #define ACBADDR         (iface->base + 4)
104 #define ACBCTL2         (iface->base + 5)
105 #define    ACBCTL2_ENABLE       0x01
106 
107 /************************************************************************/
108 
109 static void scx200_acb_machine(struct scx200_acb_iface *iface, u8 status)
110 {
111         const char *errmsg;
112 
113         dev_dbg(&iface->adapter.dev, "state %s, status = 0x%02x\n",
114                 scx200_acb_state_name[iface->state], status);
115 
116         if (status & ACBST_BER) {
117                 errmsg = "bus error";
118                 goto error;
119         }
120         if (!(status & ACBST_MASTER)) {
121                 errmsg = "not master";
122                 goto error;
123         }
124         if (status & ACBST_NEGACK) {
125                 dev_dbg(&iface->adapter.dev, "negative ack in state %s\n",
126                         scx200_acb_state_name[iface->state]);
127 
128                 iface->state = state_idle;
129                 iface->result = -ENXIO;
130 
131                 outb(inb(ACBCTL1) | ACBCTL1_STOP, ACBCTL1);
132                 outb(ACBST_STASTR | ACBST_NEGACK, ACBST);
133 
134                 /* Reset the status register */
135                 outb(0, ACBST);
136                 return;
137         }
138 
139         switch (iface->state) {
140         case state_idle:
141                 dev_warn(&iface->adapter.dev, "interrupt in idle state\n");
142                 break;
143 
144         case state_address:
145                 /* Do a pointer write first */
146                 outb(iface->address_byte & ~1, ACBSDA);
147 
148                 iface->state = state_command;
149                 break;
150 
151         case state_command:
152                 outb(iface->command, ACBSDA);
153 
154                 if (iface->address_byte & 1)
155                         iface->state = state_repeat_start;
156                 else
157                         iface->state = state_write;
158                 break;
159 
160         case state_repeat_start:
161                 outb(inb(ACBCTL1) | ACBCTL1_START, ACBCTL1);
162                 /* fallthrough */
163 
164         case state_quick:
165                 if (iface->address_byte & 1) {
166                         if (iface->len == 1)
167                                 outb(inb(ACBCTL1) | ACBCTL1_ACK, ACBCTL1);
168                         else
169                                 outb(inb(ACBCTL1) & ~ACBCTL1_ACK, ACBCTL1);
170                         outb(iface->address_byte, ACBSDA);
171 
172                         iface->state = state_read;
173                 } else {
174                         outb(iface->address_byte, ACBSDA);
175 
176                         iface->state = state_write;
177                 }
178                 break;
179 
180         case state_read:
181                 /* Set ACK if _next_ byte will be the last one */
182                 if (iface->len == 2)
183                         outb(inb(ACBCTL1) | ACBCTL1_ACK, ACBCTL1);
184                 else
185                         outb(inb(ACBCTL1) & ~ACBCTL1_ACK, ACBCTL1);
186 
187                 if (iface->len == 1) {
188                         iface->result = 0;
189                         iface->state = state_idle;
190                         outb(inb(ACBCTL1) | ACBCTL1_STOP, ACBCTL1);
191                 }
192 
193                 *iface->ptr++ = inb(ACBSDA);
194                 --iface->len;
195 
196                 break;
197 
198         case state_write:
199                 if (iface->len == 0) {
200                         iface->result = 0;
201                         iface->state = state_idle;
202                         outb(inb(ACBCTL1) | ACBCTL1_STOP, ACBCTL1);
203                         break;
204                 }
205 
206                 outb(*iface->ptr++, ACBSDA);
207                 --iface->len;
208 
209                 break;
210         }
211 
212         return;
213 
214  error:
215         dev_err(&iface->adapter.dev,
216                 "%s in state %s (addr=0x%02x, len=%d, status=0x%02x)\n", errmsg,
217                 scx200_acb_state_name[iface->state], iface->address_byte,
218                 iface->len, status);
219 
220         iface->state = state_idle;
221         iface->result = -EIO;
222         iface->needs_reset = 1;
223 }
224 
225 static void scx200_acb_poll(struct scx200_acb_iface *iface)
226 {
227         u8 status;
228         unsigned long timeout;
229 
230         timeout = jiffies + POLL_TIMEOUT;
231         while (1) {
232                 status = inb(ACBST);
233 
234                 /* Reset the status register to avoid the hang */
235                 outb(0, ACBST);
236 
237                 if ((status & (ACBST_SDAST|ACBST_BER|ACBST_NEGACK)) != 0) {
238                         scx200_acb_machine(iface, status);
239                         return;
240                 }
241                 if (time_after(jiffies, timeout))
242                         break;
243                 cpu_relax();
244                 cond_resched();
245         }
246 
247         dev_err(&iface->adapter.dev, "timeout in state %s\n",
248                 scx200_acb_state_name[iface->state]);
249 
250         iface->state = state_idle;
251         iface->result = -EIO;
252         iface->needs_reset = 1;
253 }
254 
255 static void scx200_acb_reset(struct scx200_acb_iface *iface)
256 {
257         /* Disable the ACCESS.bus device and Configure the SCL
258            frequency: 16 clock cycles */
259         outb(0x70, ACBCTL2);
260         /* Polling mode */
261         outb(0, ACBCTL1);
262         /* Disable slave address */
263         outb(0, ACBADDR);
264         /* Enable the ACCESS.bus device */
265         outb(inb(ACBCTL2) | ACBCTL2_ENABLE, ACBCTL2);
266         /* Free STALL after START */
267         outb(inb(ACBCTL1) & ~(ACBCTL1_STASTRE | ACBCTL1_NMINTE), ACBCTL1);
268         /* Send a STOP */
269         outb(inb(ACBCTL1) | ACBCTL1_STOP, ACBCTL1);
270         /* Clear BER, NEGACK and STASTR bits */
271         outb(ACBST_BER | ACBST_NEGACK | ACBST_STASTR, ACBST);
272         /* Clear BB bit */
273         outb(inb(ACBCST) | ACBCST_BB, ACBCST);
274 }
275 
276 static s32 scx200_acb_smbus_xfer(struct i2c_adapter *adapter,
277                                  u16 address, unsigned short flags,
278                                  char rw, u8 command, int size,
279                                  union i2c_smbus_data *data)
280 {
281         struct scx200_acb_iface *iface = i2c_get_adapdata(adapter);
282         int len;
283         u8 *buffer;
284         u16 cur_word;
285         int rc;
286 
287         switch (size) {
288         case I2C_SMBUS_QUICK:
289                 len = 0;
290                 buffer = NULL;
291                 break;
292 
293         case I2C_SMBUS_BYTE:
294                 len = 1;
295                 buffer = rw ? &data->byte : &command;
296                 break;
297 
298         case I2C_SMBUS_BYTE_DATA:
299                 len = 1;
300                 buffer = &data->byte;
301                 break;
302 
303         case I2C_SMBUS_WORD_DATA:
304                 len = 2;
305                 cur_word = cpu_to_le16(data->word);
306                 buffer = (u8 *)&cur_word;
307                 break;
308 
309         case I2C_SMBUS_I2C_BLOCK_DATA:
310                 len = data->block[0];
311                 if (len == 0 || len > I2C_SMBUS_BLOCK_MAX)
312                         return -EINVAL;
313                 buffer = &data->block[1];
314                 break;
315 
316         default:
317                 return -EINVAL;
318         }
319 
320         dev_dbg(&adapter->dev,
321                 "size=%d, address=0x%x, command=0x%x, len=%d, read=%d\n",
322                 size, address, command, len, rw);
323 
324         if (!len && rw == I2C_SMBUS_READ) {
325                 dev_dbg(&adapter->dev, "zero length read\n");
326                 return -EINVAL;
327         }
328 
329         mutex_lock(&iface->mutex);
330 
331         iface->address_byte = (address << 1) | rw;
332         iface->command = command;
333         iface->ptr = buffer;
334         iface->len = len;
335         iface->result = -EINVAL;
336         iface->needs_reset = 0;
337 
338         outb(inb(ACBCTL1) | ACBCTL1_START, ACBCTL1);
339 
340         if (size == I2C_SMBUS_QUICK || size == I2C_SMBUS_BYTE)
341                 iface->state = state_quick;
342         else
343                 iface->state = state_address;
344 
345         while (iface->state != state_idle)
346                 scx200_acb_poll(iface);
347 
348         if (iface->needs_reset)
349                 scx200_acb_reset(iface);
350 
351         rc = iface->result;
352 
353         mutex_unlock(&iface->mutex);
354 
355         if (rc == 0 && size == I2C_SMBUS_WORD_DATA && rw == I2C_SMBUS_READ)
356                 data->word = le16_to_cpu(cur_word);
357 
358 #ifdef DEBUG
359         dev_dbg(&adapter->dev, "transfer done, result: %d", rc);
360         if (buffer) {
361                 int i;
362                 printk(" data:");
363                 for (i = 0; i < len; ++i)
364                         printk(" %02x", buffer[i]);
365         }
366         printk("\n");
367 #endif
368 
369         return rc;
370 }
371 
372 static u32 scx200_acb_func(struct i2c_adapter *adapter)
373 {
374         return I2C_FUNC_SMBUS_QUICK | I2C_FUNC_SMBUS_BYTE |
375                I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA |
376                I2C_FUNC_SMBUS_I2C_BLOCK;
377 }
378 
379 /* For now, we only handle combined mode (smbus) */
380 static const struct i2c_algorithm scx200_acb_algorithm = {
381         .smbus_xfer     = scx200_acb_smbus_xfer,
382         .functionality  = scx200_acb_func,
383 };
384 
385 static struct scx200_acb_iface *scx200_acb_list;
386 static DEFINE_MUTEX(scx200_acb_list_mutex);
387 
388 static int scx200_acb_probe(struct scx200_acb_iface *iface)
389 {
390         u8 val;
391 
392         /* Disable the ACCESS.bus device and Configure the SCL
393            frequency: 16 clock cycles */
394         outb(0x70, ACBCTL2);
395 
396         if (inb(ACBCTL2) != 0x70) {
397                 pr_debug("ACBCTL2 readback failed\n");
398                 return -ENXIO;
399         }
400 
401         outb(inb(ACBCTL1) | ACBCTL1_NMINTE, ACBCTL1);
402 
403         val = inb(ACBCTL1);
404         if (val) {
405                 pr_debug("disabled, but ACBCTL1=0x%02x\n", val);
406                 return -ENXIO;
407         }
408 
409         outb(inb(ACBCTL2) | ACBCTL2_ENABLE, ACBCTL2);
410 
411         outb(inb(ACBCTL1) | ACBCTL1_NMINTE, ACBCTL1);
412 
413         val = inb(ACBCTL1);
414         if ((val & ACBCTL1_NMINTE) != ACBCTL1_NMINTE) {
415                 pr_debug("enabled, but NMINTE won't be set, ACBCTL1=0x%02x\n",
416                          val);
417                 return -ENXIO;
418         }
419 
420         return 0;
421 }
422 
423 static struct scx200_acb_iface *scx200_create_iface(const char *text,
424                 struct device *dev, int index)
425 {
426         struct scx200_acb_iface *iface;
427         struct i2c_adapter *adapter;
428 
429         iface = kzalloc(sizeof(*iface), GFP_KERNEL);
430         if (!iface)
431                 return NULL;
432 
433         adapter = &iface->adapter;
434         i2c_set_adapdata(adapter, iface);
435         snprintf(adapter->name, sizeof(adapter->name), "%s ACB%d", text, index);
436         adapter->owner = THIS_MODULE;
437         adapter->algo = &scx200_acb_algorithm;
438         adapter->class = I2C_CLASS_HWMON | I2C_CLASS_SPD;
439         adapter->dev.parent = dev;
440 
441         mutex_init(&iface->mutex);
442 
443         return iface;
444 }
445 
446 static int scx200_acb_create(struct scx200_acb_iface *iface)
447 {
448         struct i2c_adapter *adapter;
449         int rc;
450 
451         adapter = &iface->adapter;
452 
453         rc = scx200_acb_probe(iface);
454         if (rc) {
455                 pr_warn("probe failed\n");
456                 return rc;
457         }
458 
459         scx200_acb_reset(iface);
460 
461         if (i2c_add_adapter(adapter) < 0) {
462                 pr_err("failed to register\n");
463                 return -ENODEV;
464         }
465 
466         if (!adapter->dev.parent) {
467                 /* If there's no dev, we're tracking (ISA) ifaces manually */
468                 mutex_lock(&scx200_acb_list_mutex);
469                 iface->next = scx200_acb_list;
470                 scx200_acb_list = iface;
471                 mutex_unlock(&scx200_acb_list_mutex);
472         }
473 
474         return 0;
475 }
476 
477 static struct scx200_acb_iface *scx200_create_dev(const char *text,
478                 unsigned long base, int index, struct device *dev)
479 {
480         struct scx200_acb_iface *iface;
481         int rc;
482 
483         iface = scx200_create_iface(text, dev, index);
484 
485         if (iface == NULL)
486                 return NULL;
487 
488         if (!request_region(base, 8, iface->adapter.name)) {
489                 pr_err("can't allocate io 0x%lx-0x%lx\n", base, base + 8 - 1);
490                 goto errout_free;
491         }
492 
493         iface->base = base;
494         rc = scx200_acb_create(iface);
495 
496         if (rc == 0)
497                 return iface;
498 
499         release_region(base, 8);
500  errout_free:
501         kfree(iface);
502         return NULL;
503 }
504 
505 static int scx200_probe(struct platform_device *pdev)
506 {
507         struct scx200_acb_iface *iface;
508         struct resource *res;
509 
510         res = platform_get_resource(pdev, IORESOURCE_IO, 0);
511         if (!res) {
512                 dev_err(&pdev->dev, "can't fetch device resource info\n");
513                 return -ENODEV;
514         }
515 
516         iface = scx200_create_dev("CS5535", res->start, 0, &pdev->dev);
517         if (!iface)
518                 return -EIO;
519 
520         dev_info(&pdev->dev, "SCx200 device '%s' registered\n",
521                         iface->adapter.name);
522         platform_set_drvdata(pdev, iface);
523 
524         return 0;
525 }
526 
527 static void scx200_cleanup_iface(struct scx200_acb_iface *iface)
528 {
529         i2c_del_adapter(&iface->adapter);
530         release_region(iface->base, 8);
531         kfree(iface);
532 }
533 
534 static int scx200_remove(struct platform_device *pdev)
535 {
536         struct scx200_acb_iface *iface;
537 
538         iface = platform_get_drvdata(pdev);
539         scx200_cleanup_iface(iface);
540 
541         return 0;
542 }
543 
544 static struct platform_driver scx200_pci_driver = {
545         .driver = {
546                 .name = "cs5535-smb",
547                 .owner = THIS_MODULE,
548         },
549         .probe = scx200_probe,
550         .remove = scx200_remove,
551 };
552 
553 static const struct pci_device_id scx200_isa[] = {
554         { PCI_DEVICE(PCI_VENDOR_ID_NS, PCI_DEVICE_ID_NS_SCx200_BRIDGE) },
555         { PCI_DEVICE(PCI_VENDOR_ID_NS, PCI_DEVICE_ID_NS_SC1100_BRIDGE) },
556         { 0, }
557 };
558 
559 static __init void scx200_scan_isa(void)
560 {
561         int i;
562 
563         if (!pci_dev_present(scx200_isa))
564                 return;
565 
566         for (i = 0; i < MAX_DEVICES; ++i) {
567                 if (base[i] == 0)
568                         continue;
569 
570                 /* XXX: should we care about failures? */
571                 scx200_create_dev("SCx200", base[i], i, NULL);
572         }
573 }
574 
575 static int __init scx200_acb_init(void)
576 {
577         pr_debug("NatSemi SCx200 ACCESS.bus Driver\n");
578 
579         /* First scan for ISA-based devices */
580         scx200_scan_isa();      /* XXX: should we care about errors? */
581 
582         /* If at least one bus was created, init must succeed */
583         if (scx200_acb_list)
584                 return 0;
585 
586         /* No ISA devices; register the platform driver for PCI-based devices */
587         return platform_driver_register(&scx200_pci_driver);
588 }
589 
590 static void __exit scx200_acb_cleanup(void)
591 {
592         struct scx200_acb_iface *iface;
593 
594         platform_driver_unregister(&scx200_pci_driver);
595 
596         mutex_lock(&scx200_acb_list_mutex);
597         while ((iface = scx200_acb_list) != NULL) {
598                 scx200_acb_list = iface->next;
599                 mutex_unlock(&scx200_acb_list_mutex);
600 
601                 scx200_cleanup_iface(iface);
602 
603                 mutex_lock(&scx200_acb_list_mutex);
604         }
605         mutex_unlock(&scx200_acb_list_mutex);
606 }
607 
608 module_init(scx200_acb_init);
609 module_exit(scx200_acb_cleanup);
610 

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