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34#include <linux/module.h>
35#include <linux/kernel.h>
36#include <linux/ioport.h>
37#include <linux/delay.h>
38#include <linux/slab.h>
39#include <linux/init.h>
40#include <linux/interrupt.h>
41#include <asm/irq.h>
42#include <linux/io.h>
43#include <linux/i2c.h>
44#include <linux/of_platform.h>
45
46#include "i2c-ibm_iic.h"
47
48#define DRIVER_VERSION "2.2"
49
50MODULE_DESCRIPTION("IBM IIC driver v" DRIVER_VERSION);
51MODULE_LICENSE("GPL");
52
53static bool iic_force_poll;
54module_param(iic_force_poll, bool, 0);
55MODULE_PARM_DESC(iic_force_poll, "Force polling mode");
56
57static bool iic_force_fast;
58module_param(iic_force_fast, bool, 0);
59MODULE_PARM_DESC(iic_force_fast, "Force fast mode (400 kHz)");
60
61#define DBG_LEVEL 0
62
63#ifdef DBG
64#undef DBG
65#endif
66
67#ifdef DBG2
68#undef DBG2
69#endif
70
71#if DBG_LEVEL > 0
72# define DBG(f,x...) printk(KERN_DEBUG "ibm-iic" f, ##x)
73#else
74# define DBG(f,x...) ((void)0)
75#endif
76#if DBG_LEVEL > 1
77# define DBG2(f,x...) DBG(f, ##x)
78#else
79# define DBG2(f,x...) ((void)0)
80#endif
81#if DBG_LEVEL > 2
82static void dump_iic_regs(const char* header, struct ibm_iic_private* dev)
83{
84 volatile struct iic_regs __iomem *iic = dev->vaddr;
85 printk(KERN_DEBUG "ibm-iic%d: %s\n", dev->idx, header);
86 printk(KERN_DEBUG
87 " cntl = 0x%02x, mdcntl = 0x%02x\n"
88 " sts = 0x%02x, extsts = 0x%02x\n"
89 " clkdiv = 0x%02x, xfrcnt = 0x%02x\n"
90 " xtcntlss = 0x%02x, directcntl = 0x%02x\n",
91 in_8(&iic->cntl), in_8(&iic->mdcntl), in_8(&iic->sts),
92 in_8(&iic->extsts), in_8(&iic->clkdiv), in_8(&iic->xfrcnt),
93 in_8(&iic->xtcntlss), in_8(&iic->directcntl));
94}
95# define DUMP_REGS(h,dev) dump_iic_regs((h),(dev))
96#else
97# define DUMP_REGS(h,dev) ((void)0)
98#endif
99
100
101static struct i2c_timings {
102 unsigned int hd_sta;
103 unsigned int su_sto;
104 unsigned int low;
105 unsigned int high;
106 unsigned int buf;
107} timings [] = {
108
109{
110 .hd_sta = 4000,
111 .su_sto = 4000,
112 .low = 4700,
113 .high = 4000,
114 .buf = 4700,
115},
116
117{
118 .hd_sta = 600,
119 .su_sto = 600,
120 .low = 1300,
121 .high = 600,
122 .buf = 1300,
123}};
124
125
126static inline void iic_interrupt_mode(struct ibm_iic_private* dev, int enable)
127{
128 out_8(&dev->vaddr->intmsk, enable ? INTRMSK_EIMTC : 0);
129}
130
131
132
133
134static void iic_dev_init(struct ibm_iic_private* dev)
135{
136 volatile struct iic_regs __iomem *iic = dev->vaddr;
137
138 DBG("%d: init\n", dev->idx);
139
140
141 out_8(&iic->lmadr, 0);
142 out_8(&iic->hmadr, 0);
143
144
145 out_8(&iic->lsadr, 0);
146 out_8(&iic->hsadr, 0);
147
148
149 out_8(&iic->sts, STS_SCMP | STS_IRQA);
150 out_8(&iic->extsts, EXTSTS_IRQP | EXTSTS_IRQD | EXTSTS_LA
151 | EXTSTS_ICT | EXTSTS_XFRA);
152
153
154 out_8(&iic->clkdiv, dev->clckdiv);
155
156
157 out_8(&iic->xfrcnt, 0);
158
159
160 out_8(&iic->xtcntlss, XTCNTLSS_SRC | XTCNTLSS_SRS | XTCNTLSS_SWC
161 | XTCNTLSS_SWS);
162
163
164 out_8(&iic->cntl, 0);
165
166
167 iic_interrupt_mode(dev, dev->irq >= 0);
168
169
170 out_8(&iic->mdcntl, MDCNTL_FMDB | MDCNTL_EINT | MDCNTL_EUBS
171 | (dev->fast_mode ? MDCNTL_FSM : 0));
172
173 DUMP_REGS("iic_init", dev);
174}
175
176
177
178
179static void iic_dev_reset(struct ibm_iic_private* dev)
180{
181 volatile struct iic_regs __iomem *iic = dev->vaddr;
182 int i;
183 u8 dc;
184
185 DBG("%d: soft reset\n", dev->idx);
186 DUMP_REGS("reset", dev);
187
188
189 out_8(&iic->xtcntlss, XTCNTLSS_SRST);
190
191
192 dc = in_8(&iic->directcntl);
193 if (!DIRCTNL_FREE(dc)){
194 DBG("%d: trying to regain bus control\n", dev->idx);
195
196
197 out_8(&iic->directcntl, DIRCNTL_SDAC | DIRCNTL_SCC);
198
199
200 for (i = 0; i < 100; ++i){
201 dc = in_8(&iic->directcntl);
202 if (DIRCTNL_FREE(dc))
203 break;
204
205
206 dc ^= DIRCNTL_SCC;
207 out_8(&iic->directcntl, dc);
208 udelay(10);
209 dc ^= DIRCNTL_SCC;
210 out_8(&iic->directcntl, dc);
211
212
213 cond_resched();
214 }
215 }
216
217
218 out_8(&iic->xtcntlss, 0);
219
220
221 iic_dev_init(dev);
222}
223
224
225
226
227
228
229static int iic_dc_wait(volatile struct iic_regs __iomem *iic, u8 mask)
230{
231 unsigned long x = jiffies + HZ / 28 + 2;
232 while ((in_8(&iic->directcntl) & mask) != mask){
233 if (unlikely(time_after(jiffies, x)))
234 return -1;
235 cond_resched();
236 }
237 return 0;
238}
239
240static int iic_smbus_quick(struct ibm_iic_private* dev, const struct i2c_msg* p)
241{
242 volatile struct iic_regs __iomem *iic = dev->vaddr;
243 const struct i2c_timings* t = &timings[dev->fast_mode ? 1 : 0];
244 u8 mask, v, sda;
245 int i, res;
246
247
248 if (unlikely(p->flags & I2C_M_TEN)){
249 DBG("%d: smbus_quick - 10 bit addresses are not supported\n",
250 dev->idx);
251 return -EINVAL;
252 }
253
254 DBG("%d: smbus_quick(0x%02x)\n", dev->idx, p->addr);
255
256
257 out_8(&iic->xtcntlss, XTCNTLSS_SRST);
258
259
260 out_8(&iic->directcntl, DIRCNTL_SDAC | DIRCNTL_SCC);
261 if (unlikely(iic_dc_wait(iic, DIRCNTL_MSDA | DIRCNTL_MSC)))
262 goto err;
263 ndelay(t->buf);
264
265
266 out_8(&iic->directcntl, DIRCNTL_SCC);
267 sda = 0;
268 ndelay(t->hd_sta);
269
270
271 v = (u8)((p->addr << 1) | ((p->flags & I2C_M_RD) ? 1 : 0));
272 for (i = 0, mask = 0x80; i < 8; ++i, mask >>= 1){
273 out_8(&iic->directcntl, sda);
274 ndelay(t->low / 2);
275 sda = (v & mask) ? DIRCNTL_SDAC : 0;
276 out_8(&iic->directcntl, sda);
277 ndelay(t->low / 2);
278
279 out_8(&iic->directcntl, DIRCNTL_SCC | sda);
280 if (unlikely(iic_dc_wait(iic, DIRCNTL_MSC)))
281 goto err;
282 ndelay(t->high);
283 }
284
285
286 out_8(&iic->directcntl, sda);
287 ndelay(t->low / 2);
288 out_8(&iic->directcntl, DIRCNTL_SDAC);
289 ndelay(t->low / 2);
290 out_8(&iic->directcntl, DIRCNTL_SDAC | DIRCNTL_SCC);
291 if (unlikely(iic_dc_wait(iic, DIRCNTL_MSC)))
292 goto err;
293 res = (in_8(&iic->directcntl) & DIRCNTL_MSDA) ? -EREMOTEIO : 1;
294 ndelay(t->high);
295
296
297 out_8(&iic->directcntl, 0);
298 ndelay(t->low);
299 out_8(&iic->directcntl, DIRCNTL_SCC);
300 if (unlikely(iic_dc_wait(iic, DIRCNTL_MSC)))
301 goto err;
302 ndelay(t->su_sto);
303 out_8(&iic->directcntl, DIRCNTL_SDAC | DIRCNTL_SCC);
304
305 ndelay(t->buf);
306
307 DBG("%d: smbus_quick -> %s\n", dev->idx, res ? "NACK" : "ACK");
308out:
309
310 out_8(&iic->xtcntlss, 0);
311
312
313 iic_dev_init(dev);
314
315 return res;
316err:
317 DBG("%d: smbus_quick - bus is stuck\n", dev->idx);
318 res = -EREMOTEIO;
319 goto out;
320}
321
322
323
324
325static irqreturn_t iic_handler(int irq, void *dev_id)
326{
327 struct ibm_iic_private* dev = (struct ibm_iic_private*)dev_id;
328 volatile struct iic_regs __iomem *iic = dev->vaddr;
329
330 DBG2("%d: irq handler, STS = 0x%02x, EXTSTS = 0x%02x\n",
331 dev->idx, in_8(&iic->sts), in_8(&iic->extsts));
332
333
334 out_8(&iic->sts, STS_IRQA | STS_SCMP);
335 wake_up_interruptible(&dev->wq);
336
337 return IRQ_HANDLED;
338}
339
340
341
342
343
344static int iic_xfer_result(struct ibm_iic_private* dev)
345{
346 volatile struct iic_regs __iomem *iic = dev->vaddr;
347
348 if (unlikely(in_8(&iic->sts) & STS_ERR)){
349 DBG("%d: xfer error, EXTSTS = 0x%02x\n", dev->idx,
350 in_8(&iic->extsts));
351
352
353 out_8(&iic->extsts, EXTSTS_IRQP | EXTSTS_IRQD |
354 EXTSTS_LA | EXTSTS_ICT | EXTSTS_XFRA);
355
356
357 out_8(&iic->mdcntl, in_8(&iic->mdcntl) | MDCNTL_FMDB);
358
359
360
361
362
363
364 if ((in_8(&iic->extsts) & EXTSTS_BCS_MASK) != EXTSTS_BCS_FREE){
365 DBG("%d: bus is stuck, resetting\n", dev->idx);
366 iic_dev_reset(dev);
367 }
368 return -EREMOTEIO;
369 }
370 else
371 return in_8(&iic->xfrcnt) & XFRCNT_MTC_MASK;
372}
373
374
375
376
377static void iic_abort_xfer(struct ibm_iic_private* dev)
378{
379 volatile struct iic_regs __iomem *iic = dev->vaddr;
380 unsigned long x;
381
382 DBG("%d: iic_abort_xfer\n", dev->idx);
383
384 out_8(&iic->cntl, CNTL_HMT);
385
386
387
388
389
390 x = jiffies + 2;
391 while ((in_8(&iic->extsts) & EXTSTS_BCS_MASK) != EXTSTS_BCS_FREE){
392 if (time_after(jiffies, x)){
393 DBG("%d: abort timeout, resetting...\n", dev->idx);
394 iic_dev_reset(dev);
395 return;
396 }
397 schedule();
398 }
399
400
401 iic_xfer_result(dev);
402}
403
404
405
406
407
408
409static int iic_wait_for_tc(struct ibm_iic_private* dev){
410
411 volatile struct iic_regs __iomem *iic = dev->vaddr;
412 int ret = 0;
413
414 if (dev->irq >= 0){
415
416 ret = wait_event_interruptible_timeout(dev->wq,
417 !(in_8(&iic->sts) & STS_PT), dev->adap.timeout);
418
419 if (unlikely(ret < 0))
420 DBG("%d: wait interrupted\n", dev->idx);
421 else if (unlikely(in_8(&iic->sts) & STS_PT)){
422 DBG("%d: wait timeout\n", dev->idx);
423 ret = -ETIMEDOUT;
424 }
425 }
426 else {
427
428 unsigned long x = jiffies + dev->adap.timeout;
429
430 while (in_8(&iic->sts) & STS_PT){
431 if (unlikely(time_after(jiffies, x))){
432 DBG("%d: poll timeout\n", dev->idx);
433 ret = -ETIMEDOUT;
434 break;
435 }
436
437 if (unlikely(signal_pending(current))){
438 DBG("%d: poll interrupted\n", dev->idx);
439 ret = -ERESTARTSYS;
440 break;
441 }
442 schedule();
443 }
444 }
445
446 if (unlikely(ret < 0))
447 iic_abort_xfer(dev);
448 else
449 ret = iic_xfer_result(dev);
450
451 DBG2("%d: iic_wait_for_tc -> %d\n", dev->idx, ret);
452
453 return ret;
454}
455
456
457
458
459static int iic_xfer_bytes(struct ibm_iic_private* dev, struct i2c_msg* pm,
460 int combined_xfer)
461{
462 volatile struct iic_regs __iomem *iic = dev->vaddr;
463 char* buf = pm->buf;
464 int i, j, loops, ret = 0;
465 int len = pm->len;
466
467 u8 cntl = (in_8(&iic->cntl) & CNTL_AMD) | CNTL_PT;
468 if (pm->flags & I2C_M_RD)
469 cntl |= CNTL_RW;
470
471 loops = (len + 3) / 4;
472 for (i = 0; i < loops; ++i, len -= 4){
473 int count = len > 4 ? 4 : len;
474 u8 cmd = cntl | ((count - 1) << CNTL_TCT_SHIFT);
475
476 if (!(cntl & CNTL_RW))
477 for (j = 0; j < count; ++j)
478 out_8((void __iomem *)&iic->mdbuf, *buf++);
479
480 if (i < loops - 1)
481 cmd |= CNTL_CHT;
482 else if (combined_xfer)
483 cmd |= CNTL_RPST;
484
485 DBG2("%d: xfer_bytes, %d, CNTL = 0x%02x\n", dev->idx, count, cmd);
486
487
488 out_8(&iic->cntl, cmd);
489
490
491 ret = iic_wait_for_tc(dev);
492
493 if (unlikely(ret < 0))
494 break;
495 else if (unlikely(ret != count)){
496 DBG("%d: xfer_bytes, requested %d, transferred %d\n",
497 dev->idx, count, ret);
498
499
500 if (combined_xfer || (i < loops - 1))
501 iic_abort_xfer(dev);
502
503 ret = -EREMOTEIO;
504 break;
505 }
506
507 if (cntl & CNTL_RW)
508 for (j = 0; j < count; ++j)
509 *buf++ = in_8((void __iomem *)&iic->mdbuf);
510 }
511
512 return ret > 0 ? 0 : ret;
513}
514
515
516
517
518static inline void iic_address(struct ibm_iic_private* dev, struct i2c_msg* msg)
519{
520 volatile struct iic_regs __iomem *iic = dev->vaddr;
521 u16 addr = msg->addr;
522
523 DBG2("%d: iic_address, 0x%03x (%d-bit)\n", dev->idx,
524 addr, msg->flags & I2C_M_TEN ? 10 : 7);
525
526 if (msg->flags & I2C_M_TEN){
527 out_8(&iic->cntl, CNTL_AMD);
528 out_8(&iic->lmadr, addr);
529 out_8(&iic->hmadr, 0xf0 | ((addr >> 7) & 0x06));
530 }
531 else {
532 out_8(&iic->cntl, 0);
533 out_8(&iic->lmadr, addr << 1);
534 }
535}
536
537static inline int iic_invalid_address(const struct i2c_msg* p)
538{
539 return (p->addr > 0x3ff) || (!(p->flags & I2C_M_TEN) && (p->addr > 0x7f));
540}
541
542static inline int iic_address_neq(const struct i2c_msg* p1,
543 const struct i2c_msg* p2)
544{
545 return (p1->addr != p2->addr)
546 || ((p1->flags & I2C_M_TEN) != (p2->flags & I2C_M_TEN));
547}
548
549
550
551
552
553static int iic_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
554{
555 struct ibm_iic_private* dev = (struct ibm_iic_private*)(i2c_get_adapdata(adap));
556 volatile struct iic_regs __iomem *iic = dev->vaddr;
557 int i, ret = 0;
558
559 DBG2("%d: iic_xfer, %d msg(s)\n", dev->idx, num);
560
561 if (!num)
562 return 0;
563
564
565
566
567 if (unlikely(iic_invalid_address(&msgs[0]))){
568 DBG("%d: invalid address 0x%03x (%d-bit)\n", dev->idx,
569 msgs[0].addr, msgs[0].flags & I2C_M_TEN ? 10 : 7);
570 return -EINVAL;
571 }
572 for (i = 0; i < num; ++i){
573 if (unlikely(msgs[i].len <= 0)){
574 if (num == 1 && !msgs[0].len){
575
576
577
578
579 return iic_smbus_quick(dev, &msgs[0]);
580 }
581 DBG("%d: invalid len %d in msg[%d]\n", dev->idx,
582 msgs[i].len, i);
583 return -EINVAL;
584 }
585 if (unlikely(iic_address_neq(&msgs[0], &msgs[i]))){
586 DBG("%d: invalid addr in msg[%d]\n", dev->idx, i);
587 return -EINVAL;
588 }
589 }
590
591
592 if (unlikely((in_8(&iic->extsts) & EXTSTS_BCS_MASK) != EXTSTS_BCS_FREE)){
593 DBG("%d: iic_xfer, bus is not free\n", dev->idx);
594
595
596
597
598
599
600
601
602
603 iic_dev_reset(dev);
604
605 if ((in_8(&iic->extsts) & EXTSTS_BCS_MASK) != EXTSTS_BCS_FREE){
606 DBG("%d: iic_xfer, bus is still not free\n", dev->idx);
607 return -EREMOTEIO;
608 }
609 }
610 else {
611
612 out_8(&iic->mdcntl, in_8(&iic->mdcntl) | MDCNTL_FMDB);
613 }
614
615
616 iic_address(dev, &msgs[0]);
617
618
619 for (i = 0; i < num && !ret; ++i)
620 ret = iic_xfer_bytes(dev, &msgs[i], i < num - 1);
621
622 return ret < 0 ? ret : num;
623}
624
625static u32 iic_func(struct i2c_adapter *adap)
626{
627 return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_10BIT_ADDR;
628}
629
630static const struct i2c_algorithm iic_algo = {
631 .master_xfer = iic_xfer,
632 .functionality = iic_func
633};
634
635
636
637
638static inline u8 iic_clckdiv(unsigned int opb)
639{
640
641
642
643
644
645 if (!opb){
646 printk(KERN_WARNING "ibm-iic: using compatibility value for OPB freq,"
647 " fix your board specific setup\n");
648 opb = 50000000;
649 }
650
651
652 opb /= 1000000;
653
654 if (opb < 20 || opb > 150){
655 printk(KERN_WARNING "ibm-iic: invalid OPB clock frequency %u MHz\n",
656 opb);
657 opb = opb < 20 ? 20 : 150;
658 }
659 return (u8)((opb + 9) / 10 - 1);
660}
661
662static int iic_request_irq(struct platform_device *ofdev,
663 struct ibm_iic_private *dev)
664{
665 struct device_node *np = ofdev->dev.of_node;
666 int irq;
667
668 if (iic_force_poll)
669 return 0;
670
671 irq = irq_of_parse_and_map(np, 0);
672 if (!irq) {
673 dev_err(&ofdev->dev, "irq_of_parse_and_map failed\n");
674 return 0;
675 }
676
677
678
679
680 iic_interrupt_mode(dev, 0);
681 if (request_irq(irq, iic_handler, 0, "IBM IIC", dev)) {
682 dev_err(&ofdev->dev, "request_irq %d failed\n", irq);
683
684 return 0;
685 }
686
687 return irq;
688}
689
690
691
692
693static int iic_probe(struct platform_device *ofdev)
694{
695 struct device_node *np = ofdev->dev.of_node;
696 struct ibm_iic_private *dev;
697 struct i2c_adapter *adap;
698 const u32 *freq;
699 int ret;
700
701 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
702 if (!dev) {
703 dev_err(&ofdev->dev, "failed to allocate device data\n");
704 return -ENOMEM;
705 }
706
707 platform_set_drvdata(ofdev, dev);
708
709 dev->vaddr = of_iomap(np, 0);
710 if (dev->vaddr == NULL) {
711 dev_err(&ofdev->dev, "failed to iomap device\n");
712 ret = -ENXIO;
713 goto error_cleanup;
714 }
715
716 init_waitqueue_head(&dev->wq);
717
718 dev->irq = iic_request_irq(ofdev, dev);
719 if (!dev->irq)
720 dev_warn(&ofdev->dev, "using polling mode\n");
721
722
723 if (iic_force_fast || of_get_property(np, "fast-mode", NULL))
724 dev->fast_mode = 1;
725
726 freq = of_get_property(np, "clock-frequency", NULL);
727 if (freq == NULL) {
728 freq = of_get_property(np->parent, "clock-frequency", NULL);
729 if (freq == NULL) {
730 dev_err(&ofdev->dev, "Unable to get bus frequency\n");
731 ret = -EINVAL;
732 goto error_cleanup;
733 }
734 }
735
736 dev->clckdiv = iic_clckdiv(*freq);
737 dev_dbg(&ofdev->dev, "clckdiv = %d\n", dev->clckdiv);
738
739
740 iic_dev_init(dev);
741
742
743 adap = &dev->adap;
744 adap->dev.parent = &ofdev->dev;
745 adap->dev.of_node = of_node_get(np);
746 strlcpy(adap->name, "IBM IIC", sizeof(adap->name));
747 i2c_set_adapdata(adap, dev);
748 adap->class = I2C_CLASS_HWMON | I2C_CLASS_SPD;
749 adap->algo = &iic_algo;
750 adap->timeout = HZ;
751
752 ret = i2c_add_adapter(adap);
753 if (ret < 0) {
754 dev_err(&ofdev->dev, "failed to register i2c adapter\n");
755 goto error_cleanup;
756 }
757
758 dev_info(&ofdev->dev, "using %s mode\n",
759 dev->fast_mode ? "fast (400 kHz)" : "standard (100 kHz)");
760
761 return 0;
762
763error_cleanup:
764 if (dev->irq) {
765 iic_interrupt_mode(dev, 0);
766 free_irq(dev->irq, dev);
767 }
768
769 if (dev->vaddr)
770 iounmap(dev->vaddr);
771
772 kfree(dev);
773 return ret;
774}
775
776
777
778
779static int iic_remove(struct platform_device *ofdev)
780{
781 struct ibm_iic_private *dev = platform_get_drvdata(ofdev);
782
783 i2c_del_adapter(&dev->adap);
784
785 if (dev->irq) {
786 iic_interrupt_mode(dev, 0);
787 free_irq(dev->irq, dev);
788 }
789
790 iounmap(dev->vaddr);
791 kfree(dev);
792
793 return 0;
794}
795
796static const struct of_device_id ibm_iic_match[] = {
797 { .compatible = "ibm,iic", },
798 {}
799};
800
801static struct platform_driver ibm_iic_driver = {
802 .driver = {
803 .name = "ibm-iic",
804 .owner = THIS_MODULE,
805 .of_match_table = ibm_iic_match,
806 },
807 .probe = iic_probe,
808 .remove = iic_remove,
809};
810
811module_platform_driver(ibm_iic_driver);
812