Version:  2.0.40 2.2.26 2.4.37 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 3.10 3.11 3.12 3.13 3.14 3.15 3.16 3.17

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     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                 return NULL;
436 
437         adapter = &iface->adapter;
438         i2c_set_adapdata(adapter, iface);
439         snprintf(adapter->name, sizeof(adapter->name), "%s ACB%d", text, index);
440         adapter->owner = THIS_MODULE;
441         adapter->algo = &scx200_acb_algorithm;
442         adapter->class = I2C_CLASS_HWMON | I2C_CLASS_SPD;
443         adapter->dev.parent = dev;
444 
445         mutex_init(&iface->mutex);
446 
447         return iface;
448 }
449 
450 static int scx200_acb_create(struct scx200_acb_iface *iface)
451 {
452         struct i2c_adapter *adapter;
453         int rc;
454 
455         adapter = &iface->adapter;
456 
457         rc = scx200_acb_probe(iface);
458         if (rc) {
459                 pr_warn("probe failed\n");
460                 return rc;
461         }
462 
463         scx200_acb_reset(iface);
464 
465         if (i2c_add_adapter(adapter) < 0) {
466                 pr_err("failed to register\n");
467                 return -ENODEV;
468         }
469 
470         if (!adapter->dev.parent) {
471                 /* If there's no dev, we're tracking (ISA) ifaces manually */
472                 mutex_lock(&scx200_acb_list_mutex);
473                 iface->next = scx200_acb_list;
474                 scx200_acb_list = iface;
475                 mutex_unlock(&scx200_acb_list_mutex);
476         }
477 
478         return 0;
479 }
480 
481 static struct scx200_acb_iface *scx200_create_dev(const char *text,
482                 unsigned long base, int index, struct device *dev)
483 {
484         struct scx200_acb_iface *iface;
485         int rc;
486 
487         iface = scx200_create_iface(text, dev, index);
488 
489         if (iface == NULL)
490                 return NULL;
491 
492         if (!request_region(base, 8, iface->adapter.name)) {
493                 pr_err("can't allocate io 0x%lx-0x%lx\n", base, base + 8 - 1);
494                 goto errout_free;
495         }
496 
497         iface->base = base;
498         rc = scx200_acb_create(iface);
499 
500         if (rc == 0)
501                 return iface;
502 
503         release_region(base, 8);
504  errout_free:
505         kfree(iface);
506         return NULL;
507 }
508 
509 static int scx200_probe(struct platform_device *pdev)
510 {
511         struct scx200_acb_iface *iface;
512         struct resource *res;
513 
514         res = platform_get_resource(pdev, IORESOURCE_IO, 0);
515         if (!res) {
516                 dev_err(&pdev->dev, "can't fetch device resource info\n");
517                 return -ENODEV;
518         }
519 
520         iface = scx200_create_dev("CS5535", res->start, 0, &pdev->dev);
521         if (!iface)
522                 return -EIO;
523 
524         dev_info(&pdev->dev, "SCx200 device '%s' registered\n",
525                         iface->adapter.name);
526         platform_set_drvdata(pdev, iface);
527 
528         return 0;
529 }
530 
531 static void scx200_cleanup_iface(struct scx200_acb_iface *iface)
532 {
533         i2c_del_adapter(&iface->adapter);
534         release_region(iface->base, 8);
535         kfree(iface);
536 }
537 
538 static int scx200_remove(struct platform_device *pdev)
539 {
540         struct scx200_acb_iface *iface;
541 
542         iface = platform_get_drvdata(pdev);
543         scx200_cleanup_iface(iface);
544 
545         return 0;
546 }
547 
548 static struct platform_driver scx200_pci_driver = {
549         .driver = {
550                 .name = "cs5535-smb",
551                 .owner = THIS_MODULE,
552         },
553         .probe = scx200_probe,
554         .remove = scx200_remove,
555 };
556 
557 static const struct pci_device_id scx200_isa[] = {
558         { PCI_DEVICE(PCI_VENDOR_ID_NS, PCI_DEVICE_ID_NS_SCx200_BRIDGE) },
559         { PCI_DEVICE(PCI_VENDOR_ID_NS, PCI_DEVICE_ID_NS_SC1100_BRIDGE) },
560         { 0, }
561 };
562 
563 static __init void scx200_scan_isa(void)
564 {
565         int i;
566 
567         if (!pci_dev_present(scx200_isa))
568                 return;
569 
570         for (i = 0; i < MAX_DEVICES; ++i) {
571                 if (base[i] == 0)
572                         continue;
573 
574                 /* XXX: should we care about failures? */
575                 scx200_create_dev("SCx200", base[i], i, NULL);
576         }
577 }
578 
579 static int __init scx200_acb_init(void)
580 {
581         pr_debug("NatSemi SCx200 ACCESS.bus Driver\n");
582 
583         /* First scan for ISA-based devices */
584         scx200_scan_isa();      /* XXX: should we care about errors? */
585 
586         /* If at least one bus was created, init must succeed */
587         if (scx200_acb_list)
588                 return 0;
589 
590         /* No ISA devices; register the platform driver for PCI-based devices */
591         return platform_driver_register(&scx200_pci_driver);
592 }
593 
594 static void __exit scx200_acb_cleanup(void)
595 {
596         struct scx200_acb_iface *iface;
597 
598         platform_driver_unregister(&scx200_pci_driver);
599 
600         mutex_lock(&scx200_acb_list_mutex);
601         while ((iface = scx200_acb_list) != NULL) {
602                 scx200_acb_list = iface->next;
603                 mutex_unlock(&scx200_acb_list_mutex);
604 
605                 scx200_cleanup_iface(iface);
606 
607                 mutex_lock(&scx200_acb_list_mutex);
608         }
609         mutex_unlock(&scx200_acb_list_mutex);
610 }
611 
612 module_init(scx200_acb_init);
613 module_exit(scx200_acb_cleanup);
614 

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