Merge branch 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4
[deliverable/linux.git] / drivers / i2c / busses / i2c-sh_mobile.c
1 /*
2 * SuperH Mobile I2C Controller
3 *
4 * Copyright (C) 2008 Magnus Damm
5 *
6 * Portions of the code based on out-of-tree driver i2c-sh7343.c
7 * Copyright (c) 2006 Carlos Munoz <carlos@kenati.com>
8 *
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License as published by
11 * the Free Software Foundation; either version 2 of the License
12 *
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 * GNU General Public License for more details.
17 *
18 * You should have received a copy of the GNU General Public License
19 * along with this program; if not, write to the Free Software
20 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
21 */
22
23 #include <linux/kernel.h>
24 #include <linux/module.h>
25 #include <linux/init.h>
26 #include <linux/delay.h>
27 #include <linux/platform_device.h>
28 #include <linux/interrupt.h>
29 #include <linux/i2c.h>
30 #include <linux/err.h>
31 #include <linux/clk.h>
32 #include <linux/io.h>
33
34 /* Transmit operation: */
35 /* */
36 /* 0 byte transmit */
37 /* BUS: S A8 ACK P */
38 /* IRQ: DTE WAIT */
39 /* ICIC: */
40 /* ICCR: 0x94 0x90 */
41 /* ICDR: A8 */
42 /* */
43 /* 1 byte transmit */
44 /* BUS: S A8 ACK D8(1) ACK P */
45 /* IRQ: DTE WAIT WAIT */
46 /* ICIC: -DTE */
47 /* ICCR: 0x94 0x90 */
48 /* ICDR: A8 D8(1) */
49 /* */
50 /* 2 byte transmit */
51 /* BUS: S A8 ACK D8(1) ACK D8(2) ACK P */
52 /* IRQ: DTE WAIT WAIT WAIT */
53 /* ICIC: -DTE */
54 /* ICCR: 0x94 0x90 */
55 /* ICDR: A8 D8(1) D8(2) */
56 /* */
57 /* 3 bytes or more, +---------+ gets repeated */
58 /* */
59 /* */
60 /* Receive operation: */
61 /* */
62 /* 0 byte receive - not supported since slave may hold SDA low */
63 /* */
64 /* 1 byte receive [TX] | [RX] */
65 /* BUS: S A8 ACK | D8(1) ACK P */
66 /* IRQ: DTE WAIT | WAIT DTE */
67 /* ICIC: -DTE | +DTE */
68 /* ICCR: 0x94 0x81 | 0xc0 */
69 /* ICDR: A8 | D8(1) */
70 /* */
71 /* 2 byte receive [TX]| [RX] */
72 /* BUS: S A8 ACK | D8(1) ACK D8(2) ACK P */
73 /* IRQ: DTE WAIT | WAIT WAIT DTE */
74 /* ICIC: -DTE | +DTE */
75 /* ICCR: 0x94 0x81 | 0xc0 */
76 /* ICDR: A8 | D8(1) D8(2) */
77 /* */
78 /* 3 byte receive [TX] | [RX] */
79 /* BUS: S A8 ACK | D8(1) ACK D8(2) ACK D8(3) ACK P */
80 /* IRQ: DTE WAIT | WAIT WAIT WAIT DTE */
81 /* ICIC: -DTE | +DTE */
82 /* ICCR: 0x94 0x81 | 0xc0 */
83 /* ICDR: A8 | D8(1) D8(2) D8(3) */
84 /* */
85 /* 4 bytes or more, this part is repeated +---------+ */
86 /* */
87 /* */
88 /* Interrupt order and BUSY flag */
89 /* ___ _ */
90 /* SDA ___\___XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXAAAAAAAAA___/ */
91 /* SCL \_/1\_/2\_/3\_/4\_/5\_/6\_/7\_/8\___/9\_____/ */
92 /* */
93 /* S D7 D6 D5 D4 D3 D2 D1 D0 P */
94 /* ___ */
95 /* WAIT IRQ ________________________________/ \___________ */
96 /* TACK IRQ ____________________________________/ \_______ */
97 /* DTE IRQ __________________________________________/ \_ */
98 /* AL IRQ XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX */
99 /* _______________________________________________ */
100 /* BUSY __/ \_ */
101 /* */
102
103 enum sh_mobile_i2c_op {
104 OP_START = 0,
105 OP_TX_FIRST,
106 OP_TX,
107 OP_TX_STOP,
108 OP_TX_TO_RX,
109 OP_RX,
110 OP_RX_STOP,
111 OP_RX_STOP_DATA,
112 };
113
114 struct sh_mobile_i2c_data {
115 struct device *dev;
116 void __iomem *reg;
117 struct i2c_adapter adap;
118
119 struct clk *clk;
120 u_int8_t iccl;
121 u_int8_t icch;
122
123 spinlock_t lock;
124 wait_queue_head_t wait;
125 struct i2c_msg *msg;
126 int pos;
127 int sr;
128 };
129
130 #define NORMAL_SPEED 100000 /* FAST_SPEED 400000 */
131
132 /* Register offsets */
133 #define ICDR(pd) (pd->reg + 0x00)
134 #define ICCR(pd) (pd->reg + 0x04)
135 #define ICSR(pd) (pd->reg + 0x08)
136 #define ICIC(pd) (pd->reg + 0x0c)
137 #define ICCL(pd) (pd->reg + 0x10)
138 #define ICCH(pd) (pd->reg + 0x14)
139
140 /* Register bits */
141 #define ICCR_ICE 0x80
142 #define ICCR_RACK 0x40
143 #define ICCR_TRS 0x10
144 #define ICCR_BBSY 0x04
145 #define ICCR_SCP 0x01
146
147 #define ICSR_SCLM 0x80
148 #define ICSR_SDAM 0x40
149 #define SW_DONE 0x20
150 #define ICSR_BUSY 0x10
151 #define ICSR_AL 0x08
152 #define ICSR_TACK 0x04
153 #define ICSR_WAIT 0x02
154 #define ICSR_DTE 0x01
155
156 #define ICIC_ALE 0x08
157 #define ICIC_TACKE 0x04
158 #define ICIC_WAITE 0x02
159 #define ICIC_DTEE 0x01
160
161 static void activate_ch(struct sh_mobile_i2c_data *pd)
162 {
163 /* Make sure the clock is enabled */
164 clk_enable(pd->clk);
165
166 /* Enable channel and configure rx ack */
167 iowrite8(ioread8(ICCR(pd)) | ICCR_ICE, ICCR(pd));
168
169 /* Mask all interrupts */
170 iowrite8(0, ICIC(pd));
171
172 /* Set the clock */
173 iowrite8(pd->iccl, ICCL(pd));
174 iowrite8(pd->icch, ICCH(pd));
175 }
176
177 static void deactivate_ch(struct sh_mobile_i2c_data *pd)
178 {
179 /* Clear/disable interrupts */
180 iowrite8(0, ICSR(pd));
181 iowrite8(0, ICIC(pd));
182
183 /* Disable channel */
184 iowrite8(ioread8(ICCR(pd)) & ~ICCR_ICE, ICCR(pd));
185
186 /* Disable clock */
187 clk_disable(pd->clk);
188 }
189
190 static unsigned char i2c_op(struct sh_mobile_i2c_data *pd,
191 enum sh_mobile_i2c_op op, unsigned char data)
192 {
193 unsigned char ret = 0;
194 unsigned long flags;
195
196 dev_dbg(pd->dev, "op %d, data in 0x%02x\n", op, data);
197
198 spin_lock_irqsave(&pd->lock, flags);
199
200 switch (op) {
201 case OP_START: /* issue start and trigger DTE interrupt */
202 iowrite8(0x94, ICCR(pd));
203 break;
204 case OP_TX_FIRST: /* disable DTE interrupt and write data */
205 iowrite8(ICIC_WAITE | ICIC_ALE | ICIC_TACKE, ICIC(pd));
206 iowrite8(data, ICDR(pd));
207 break;
208 case OP_TX: /* write data */
209 iowrite8(data, ICDR(pd));
210 break;
211 case OP_TX_STOP: /* write data and issue a stop afterwards */
212 iowrite8(data, ICDR(pd));
213 iowrite8(0x90, ICCR(pd));
214 break;
215 case OP_TX_TO_RX: /* select read mode */
216 iowrite8(0x81, ICCR(pd));
217 break;
218 case OP_RX: /* just read data */
219 ret = ioread8(ICDR(pd));
220 break;
221 case OP_RX_STOP: /* enable DTE interrupt, issue stop */
222 iowrite8(ICIC_DTEE | ICIC_WAITE | ICIC_ALE | ICIC_TACKE,
223 ICIC(pd));
224 iowrite8(0xc0, ICCR(pd));
225 break;
226 case OP_RX_STOP_DATA: /* enable DTE interrupt, read data, issue stop */
227 iowrite8(ICIC_DTEE | ICIC_WAITE | ICIC_ALE | ICIC_TACKE,
228 ICIC(pd));
229 ret = ioread8(ICDR(pd));
230 iowrite8(0xc0, ICCR(pd));
231 break;
232 }
233
234 spin_unlock_irqrestore(&pd->lock, flags);
235
236 dev_dbg(pd->dev, "op %d, data out 0x%02x\n", op, ret);
237 return ret;
238 }
239
240 static int sh_mobile_i2c_is_first_byte(struct sh_mobile_i2c_data *pd)
241 {
242 if (pd->pos == -1)
243 return 1;
244
245 return 0;
246 }
247
248 static int sh_mobile_i2c_is_last_byte(struct sh_mobile_i2c_data *pd)
249 {
250 if (pd->pos == (pd->msg->len - 1))
251 return 1;
252
253 return 0;
254 }
255
256 static void sh_mobile_i2c_get_data(struct sh_mobile_i2c_data *pd,
257 unsigned char *buf)
258 {
259 switch (pd->pos) {
260 case -1:
261 *buf = (pd->msg->addr & 0x7f) << 1;
262 *buf |= (pd->msg->flags & I2C_M_RD) ? 1 : 0;
263 break;
264 default:
265 *buf = pd->msg->buf[pd->pos];
266 }
267 }
268
269 static int sh_mobile_i2c_isr_tx(struct sh_mobile_i2c_data *pd)
270 {
271 unsigned char data;
272
273 if (pd->pos == pd->msg->len)
274 return 1;
275
276 sh_mobile_i2c_get_data(pd, &data);
277
278 if (sh_mobile_i2c_is_last_byte(pd))
279 i2c_op(pd, OP_TX_STOP, data);
280 else if (sh_mobile_i2c_is_first_byte(pd))
281 i2c_op(pd, OP_TX_FIRST, data);
282 else
283 i2c_op(pd, OP_TX, data);
284
285 pd->pos++;
286 return 0;
287 }
288
289 static int sh_mobile_i2c_isr_rx(struct sh_mobile_i2c_data *pd)
290 {
291 unsigned char data;
292 int real_pos;
293
294 do {
295 if (pd->pos <= -1) {
296 sh_mobile_i2c_get_data(pd, &data);
297
298 if (sh_mobile_i2c_is_first_byte(pd))
299 i2c_op(pd, OP_TX_FIRST, data);
300 else
301 i2c_op(pd, OP_TX, data);
302 break;
303 }
304
305 if (pd->pos == 0) {
306 i2c_op(pd, OP_TX_TO_RX, 0);
307 break;
308 }
309
310 real_pos = pd->pos - 2;
311
312 if (pd->pos == pd->msg->len) {
313 if (real_pos < 0) {
314 i2c_op(pd, OP_RX_STOP, 0);
315 break;
316 }
317 data = i2c_op(pd, OP_RX_STOP_DATA, 0);
318 } else
319 data = i2c_op(pd, OP_RX, 0);
320
321 pd->msg->buf[real_pos] = data;
322 } while (0);
323
324 pd->pos++;
325 return pd->pos == (pd->msg->len + 2);
326 }
327
328 static irqreturn_t sh_mobile_i2c_isr(int irq, void *dev_id)
329 {
330 struct platform_device *dev = dev_id;
331 struct sh_mobile_i2c_data *pd = platform_get_drvdata(dev);
332 unsigned char sr;
333 int wakeup;
334
335 sr = ioread8(ICSR(pd));
336 pd->sr |= sr; /* remember state */
337
338 dev_dbg(pd->dev, "i2c_isr 0x%02x 0x%02x %s %d %d!\n", sr, pd->sr,
339 (pd->msg->flags & I2C_M_RD) ? "read" : "write",
340 pd->pos, pd->msg->len);
341
342 if (sr & (ICSR_AL | ICSR_TACK)) {
343 /* don't interrupt transaction - continue to issue stop */
344 iowrite8(sr & ~(ICSR_AL | ICSR_TACK), ICSR(pd));
345 wakeup = 0;
346 } else if (pd->msg->flags & I2C_M_RD)
347 wakeup = sh_mobile_i2c_isr_rx(pd);
348 else
349 wakeup = sh_mobile_i2c_isr_tx(pd);
350
351 if (sr & ICSR_WAIT) /* TODO: add delay here to support slow acks */
352 iowrite8(sr & ~ICSR_WAIT, ICSR(pd));
353
354 if (wakeup) {
355 pd->sr |= SW_DONE;
356 wake_up(&pd->wait);
357 }
358
359 return IRQ_HANDLED;
360 }
361
362 static int start_ch(struct sh_mobile_i2c_data *pd, struct i2c_msg *usr_msg)
363 {
364 if (usr_msg->len == 0 && (usr_msg->flags & I2C_M_RD)) {
365 dev_err(pd->dev, "Unsupported zero length i2c read\n");
366 return -EIO;
367 }
368
369 /* Initialize channel registers */
370 iowrite8(ioread8(ICCR(pd)) & ~ICCR_ICE, ICCR(pd));
371
372 /* Enable channel and configure rx ack */
373 iowrite8(ioread8(ICCR(pd)) | ICCR_ICE, ICCR(pd));
374
375 /* Set the clock */
376 iowrite8(pd->iccl, ICCL(pd));
377 iowrite8(pd->icch, ICCH(pd));
378
379 pd->msg = usr_msg;
380 pd->pos = -1;
381 pd->sr = 0;
382
383 /* Enable all interrupts to begin with */
384 iowrite8(ICIC_WAITE | ICIC_ALE | ICIC_TACKE | ICIC_DTEE, ICIC(pd));
385 return 0;
386 }
387
388 static int sh_mobile_i2c_xfer(struct i2c_adapter *adapter,
389 struct i2c_msg *msgs,
390 int num)
391 {
392 struct sh_mobile_i2c_data *pd = i2c_get_adapdata(adapter);
393 struct i2c_msg *msg;
394 int err = 0;
395 u_int8_t val;
396 int i, k, retry_count;
397
398 activate_ch(pd);
399
400 /* Process all messages */
401 for (i = 0; i < num; i++) {
402 msg = &msgs[i];
403
404 err = start_ch(pd, msg);
405 if (err)
406 break;
407
408 i2c_op(pd, OP_START, 0);
409
410 /* The interrupt handler takes care of the rest... */
411 k = wait_event_timeout(pd->wait,
412 pd->sr & (ICSR_TACK | SW_DONE),
413 5 * HZ);
414 if (!k)
415 dev_err(pd->dev, "Transfer request timed out\n");
416
417 retry_count = 1000;
418 again:
419 val = ioread8(ICSR(pd));
420
421 dev_dbg(pd->dev, "val 0x%02x pd->sr 0x%02x\n", val, pd->sr);
422
423 /* the interrupt handler may wake us up before the
424 * transfer is finished, so poll the hardware
425 * until we're done.
426 */
427 if (val & ICSR_BUSY) {
428 udelay(10);
429 if (retry_count--)
430 goto again;
431
432 err = -EIO;
433 dev_err(pd->dev, "Polling timed out\n");
434 break;
435 }
436
437 /* handle missing acknowledge and arbitration lost */
438 if ((val | pd->sr) & (ICSR_TACK | ICSR_AL)) {
439 err = -EIO;
440 break;
441 }
442 }
443
444 deactivate_ch(pd);
445
446 if (!err)
447 err = num;
448 return err;
449 }
450
451 static u32 sh_mobile_i2c_func(struct i2c_adapter *adapter)
452 {
453 return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
454 }
455
456 static struct i2c_algorithm sh_mobile_i2c_algorithm = {
457 .functionality = sh_mobile_i2c_func,
458 .master_xfer = sh_mobile_i2c_xfer,
459 };
460
461 static void sh_mobile_i2c_setup_channel(struct platform_device *dev)
462 {
463 struct sh_mobile_i2c_data *pd = platform_get_drvdata(dev);
464 unsigned long peripheral_clk = clk_get_rate(pd->clk);
465 u_int32_t num;
466 u_int32_t denom;
467 u_int32_t tmp;
468
469 spin_lock_init(&pd->lock);
470 init_waitqueue_head(&pd->wait);
471
472 /* Calculate the value for iccl. From the data sheet:
473 * iccl = (p clock / transfer rate) * (L / (L + H))
474 * where L and H are the SCL low/high ratio (5/4 in this case).
475 * We also round off the result.
476 */
477 num = peripheral_clk * 5;
478 denom = NORMAL_SPEED * 9;
479 tmp = num * 10 / denom;
480 if (tmp % 10 >= 5)
481 pd->iccl = (u_int8_t)((num/denom) + 1);
482 else
483 pd->iccl = (u_int8_t)(num/denom);
484
485 /* Calculate the value for icch. From the data sheet:
486 icch = (p clock / transfer rate) * (H / (L + H)) */
487 num = peripheral_clk * 4;
488 tmp = num * 10 / denom;
489 if (tmp % 10 >= 5)
490 pd->icch = (u_int8_t)((num/denom) + 1);
491 else
492 pd->icch = (u_int8_t)(num/denom);
493 }
494
495 static int sh_mobile_i2c_hook_irqs(struct platform_device *dev, int hook)
496 {
497 struct resource *res;
498 int ret = -ENXIO;
499 int q, m;
500 int k = 0;
501 int n = 0;
502
503 while ((res = platform_get_resource(dev, IORESOURCE_IRQ, k))) {
504 for (n = res->start; hook && n <= res->end; n++) {
505 if (request_irq(n, sh_mobile_i2c_isr, IRQF_DISABLED,
506 dev->dev.bus_id, dev))
507 goto rollback;
508 }
509 k++;
510 }
511
512 if (hook)
513 return k > 0 ? 0 : -ENOENT;
514
515 k--;
516 ret = 0;
517
518 rollback:
519 for (q = k; k >= 0; k--) {
520 for (m = n; m >= res->start; m--)
521 free_irq(m, dev);
522
523 res = platform_get_resource(dev, IORESOURCE_IRQ, k - 1);
524 m = res->end;
525 }
526
527 return ret;
528 }
529
530 static int sh_mobile_i2c_probe(struct platform_device *dev)
531 {
532 struct sh_mobile_i2c_data *pd;
533 struct i2c_adapter *adap;
534 struct resource *res;
535 int size;
536 int ret;
537
538 pd = kzalloc(sizeof(struct sh_mobile_i2c_data), GFP_KERNEL);
539 if (pd == NULL) {
540 dev_err(&dev->dev, "cannot allocate private data\n");
541 return -ENOMEM;
542 }
543
544 pd->clk = clk_get(&dev->dev, "peripheral_clk");
545 if (IS_ERR(pd->clk)) {
546 dev_err(&dev->dev, "cannot get peripheral clock\n");
547 ret = PTR_ERR(pd->clk);
548 goto err;
549 }
550
551 ret = sh_mobile_i2c_hook_irqs(dev, 1);
552 if (ret) {
553 dev_err(&dev->dev, "cannot request IRQ\n");
554 goto err_clk;
555 }
556
557 pd->dev = &dev->dev;
558 platform_set_drvdata(dev, pd);
559
560 res = platform_get_resource(dev, IORESOURCE_MEM, 0);
561 if (res == NULL) {
562 dev_err(&dev->dev, "cannot find IO resource\n");
563 ret = -ENOENT;
564 goto err_irq;
565 }
566
567 size = (res->end - res->start) + 1;
568
569 pd->reg = ioremap(res->start, size);
570 if (pd->reg == NULL) {
571 dev_err(&dev->dev, "cannot map IO\n");
572 ret = -ENXIO;
573 goto err_irq;
574 }
575
576 /* setup the private data */
577 adap = &pd->adap;
578 i2c_set_adapdata(adap, pd);
579
580 adap->owner = THIS_MODULE;
581 adap->algo = &sh_mobile_i2c_algorithm;
582 adap->dev.parent = &dev->dev;
583 adap->retries = 5;
584 adap->nr = dev->id;
585
586 strlcpy(adap->name, dev->name, sizeof(adap->name));
587
588 sh_mobile_i2c_setup_channel(dev);
589
590 ret = i2c_add_numbered_adapter(adap);
591 if (ret < 0) {
592 dev_err(&dev->dev, "cannot add numbered adapter\n");
593 goto err_all;
594 }
595
596 return 0;
597
598 err_all:
599 iounmap(pd->reg);
600 err_irq:
601 sh_mobile_i2c_hook_irqs(dev, 0);
602 err_clk:
603 clk_put(pd->clk);
604 err:
605 kfree(pd);
606 return ret;
607 }
608
609 static int sh_mobile_i2c_remove(struct platform_device *dev)
610 {
611 struct sh_mobile_i2c_data *pd = platform_get_drvdata(dev);
612
613 i2c_del_adapter(&pd->adap);
614 iounmap(pd->reg);
615 sh_mobile_i2c_hook_irqs(dev, 0);
616 clk_put(pd->clk);
617 kfree(pd);
618 return 0;
619 }
620
621 static struct platform_driver sh_mobile_i2c_driver = {
622 .driver = {
623 .name = "i2c-sh_mobile",
624 .owner = THIS_MODULE,
625 },
626 .probe = sh_mobile_i2c_probe,
627 .remove = sh_mobile_i2c_remove,
628 };
629
630 static int __init sh_mobile_i2c_adap_init(void)
631 {
632 return platform_driver_register(&sh_mobile_i2c_driver);
633 }
634
635 static void __exit sh_mobile_i2c_adap_exit(void)
636 {
637 platform_driver_unregister(&sh_mobile_i2c_driver);
638 }
639
640 module_init(sh_mobile_i2c_adap_init);
641 module_exit(sh_mobile_i2c_adap_exit);
642
643 MODULE_DESCRIPTION("SuperH Mobile I2C Bus Controller driver");
644 MODULE_AUTHOR("Magnus Damm");
645 MODULE_LICENSE("GPL v2");
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