Merge branch 'for-2.6.28' of git://linux-nfs.org/~bfields/linux
[linux-2.6] / 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                 if (real_pos >= 0)
322                         pd->msg->buf[real_pos] = data;
323         } while (0);
324
325         pd->pos++;
326         return pd->pos == (pd->msg->len + 2);
327 }
328
329 static irqreturn_t sh_mobile_i2c_isr(int irq, void *dev_id)
330 {
331         struct platform_device *dev = dev_id;
332         struct sh_mobile_i2c_data *pd = platform_get_drvdata(dev);
333         unsigned char sr;
334         int wakeup;
335
336         sr = ioread8(ICSR(pd));
337         pd->sr |= sr; /* remember state */
338
339         dev_dbg(pd->dev, "i2c_isr 0x%02x 0x%02x %s %d %d!\n", sr, pd->sr,
340                (pd->msg->flags & I2C_M_RD) ? "read" : "write",
341                pd->pos, pd->msg->len);
342
343         if (sr & (ICSR_AL | ICSR_TACK)) {
344                 /* don't interrupt transaction - continue to issue stop */
345                 iowrite8(sr & ~(ICSR_AL | ICSR_TACK), ICSR(pd));
346                 wakeup = 0;
347         } else if (pd->msg->flags & I2C_M_RD)
348                 wakeup = sh_mobile_i2c_isr_rx(pd);
349         else
350                 wakeup = sh_mobile_i2c_isr_tx(pd);
351
352         if (sr & ICSR_WAIT) /* TODO: add delay here to support slow acks */
353                 iowrite8(sr & ~ICSR_WAIT, ICSR(pd));
354
355         if (wakeup) {
356                 pd->sr |= SW_DONE;
357                 wake_up(&pd->wait);
358         }
359
360         return IRQ_HANDLED;
361 }
362
363 static int start_ch(struct sh_mobile_i2c_data *pd, struct i2c_msg *usr_msg)
364 {
365         if (usr_msg->len == 0 && (usr_msg->flags & I2C_M_RD)) {
366                 dev_err(pd->dev, "Unsupported zero length i2c read\n");
367                 return -EIO;
368         }
369
370         /* Initialize channel registers */
371         iowrite8(ioread8(ICCR(pd)) & ~ICCR_ICE, ICCR(pd));
372
373         /* Enable channel and configure rx ack */
374         iowrite8(ioread8(ICCR(pd)) | ICCR_ICE, ICCR(pd));
375
376         /* Set the clock */
377         iowrite8(pd->iccl, ICCL(pd));
378         iowrite8(pd->icch, ICCH(pd));
379
380         pd->msg = usr_msg;
381         pd->pos = -1;
382         pd->sr = 0;
383
384         /* Enable all interrupts to begin with */
385         iowrite8(ICIC_WAITE | ICIC_ALE | ICIC_TACKE | ICIC_DTEE, ICIC(pd));
386         return 0;
387 }
388
389 static int sh_mobile_i2c_xfer(struct i2c_adapter *adapter,
390                               struct i2c_msg *msgs,
391                               int num)
392 {
393         struct sh_mobile_i2c_data *pd = i2c_get_adapdata(adapter);
394         struct i2c_msg  *msg;
395         int err = 0;
396         u_int8_t val;
397         int i, k, retry_count;
398
399         activate_ch(pd);
400
401         /* Process all messages */
402         for (i = 0; i < num; i++) {
403                 msg = &msgs[i];
404
405                 err = start_ch(pd, msg);
406                 if (err)
407                         break;
408
409                 i2c_op(pd, OP_START, 0);
410
411                 /* The interrupt handler takes care of the rest... */
412                 k = wait_event_timeout(pd->wait,
413                                        pd->sr & (ICSR_TACK | SW_DONE),
414                                        5 * HZ);
415                 if (!k)
416                         dev_err(pd->dev, "Transfer request timed out\n");
417
418                 retry_count = 1000;
419 again:
420                 val = ioread8(ICSR(pd));
421
422                 dev_dbg(pd->dev, "val 0x%02x pd->sr 0x%02x\n", val, pd->sr);
423
424                 /* the interrupt handler may wake us up before the
425                  * transfer is finished, so poll the hardware
426                  * until we're done.
427                  */
428                 if (val & ICSR_BUSY) {
429                         udelay(10);
430                         if (retry_count--)
431                                 goto again;
432
433                         err = -EIO;
434                         dev_err(pd->dev, "Polling timed out\n");
435                         break;
436                 }
437
438                 /* handle missing acknowledge and arbitration lost */
439                 if ((val | pd->sr) & (ICSR_TACK | ICSR_AL)) {
440                         err = -EIO;
441                         break;
442                 }
443         }
444
445         deactivate_ch(pd);
446
447         if (!err)
448                 err = num;
449         return err;
450 }
451
452 static u32 sh_mobile_i2c_func(struct i2c_adapter *adapter)
453 {
454         return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
455 }
456
457 static struct i2c_algorithm sh_mobile_i2c_algorithm = {
458         .functionality  = sh_mobile_i2c_func,
459         .master_xfer    = sh_mobile_i2c_xfer,
460 };
461
462 static void sh_mobile_i2c_setup_channel(struct platform_device *dev)
463 {
464         struct sh_mobile_i2c_data *pd = platform_get_drvdata(dev);
465         unsigned long peripheral_clk = clk_get_rate(pd->clk);
466         u_int32_t num;
467         u_int32_t denom;
468         u_int32_t tmp;
469
470         spin_lock_init(&pd->lock);
471         init_waitqueue_head(&pd->wait);
472
473         /* Calculate the value for iccl. From the data sheet:
474          * iccl = (p clock / transfer rate) * (L / (L + H))
475          * where L and H are the SCL low/high ratio (5/4 in this case).
476          * We also round off the result.
477          */
478         num = peripheral_clk * 5;
479         denom = NORMAL_SPEED * 9;
480         tmp = num * 10 / denom;
481         if (tmp % 10 >= 5)
482                 pd->iccl = (u_int8_t)((num/denom) + 1);
483         else
484                 pd->iccl = (u_int8_t)(num/denom);
485
486         /* Calculate the value for icch. From the data sheet:
487            icch = (p clock / transfer rate) * (H / (L + H)) */
488         num = peripheral_clk * 4;
489         tmp = num * 10 / denom;
490         if (tmp % 10 >= 5)
491                 pd->icch = (u_int8_t)((num/denom) + 1);
492         else
493                 pd->icch = (u_int8_t)(num/denom);
494 }
495
496 static int sh_mobile_i2c_hook_irqs(struct platform_device *dev, int hook)
497 {
498         struct resource *res;
499         int ret = -ENXIO;
500         int q, m;
501         int k = 0;
502         int n = 0;
503
504         while ((res = platform_get_resource(dev, IORESOURCE_IRQ, k))) {
505                 for (n = res->start; hook && n <= res->end; n++) {
506                         if (request_irq(n, sh_mobile_i2c_isr, IRQF_DISABLED,
507                                         dev->dev.bus_id, dev))
508                                 goto rollback;
509                 }
510                 k++;
511         }
512
513         if (hook)
514                 return k > 0 ? 0 : -ENOENT;
515
516         k--;
517         ret = 0;
518
519  rollback:
520         for (q = k; k >= 0; k--) {
521                 for (m = n; m >= res->start; m--)
522                         free_irq(m, dev);
523
524                 res = platform_get_resource(dev, IORESOURCE_IRQ, k - 1);
525                 m = res->end;
526         }
527
528         return ret;
529 }
530
531 static int sh_mobile_i2c_probe(struct platform_device *dev)
532 {
533         struct sh_mobile_i2c_data *pd;
534         struct i2c_adapter *adap;
535         struct resource *res;
536         int size;
537         int ret;
538
539         pd = kzalloc(sizeof(struct sh_mobile_i2c_data), GFP_KERNEL);
540         if (pd == NULL) {
541                 dev_err(&dev->dev, "cannot allocate private data\n");
542                 return -ENOMEM;
543         }
544
545         pd->clk = clk_get(&dev->dev, "peripheral_clk");
546         if (IS_ERR(pd->clk)) {
547                 dev_err(&dev->dev, "cannot get peripheral clock\n");
548                 ret = PTR_ERR(pd->clk);
549                 goto err;
550         }
551
552         ret = sh_mobile_i2c_hook_irqs(dev, 1);
553         if (ret) {
554                 dev_err(&dev->dev, "cannot request IRQ\n");
555                 goto err_clk;
556         }
557
558         pd->dev = &dev->dev;
559         platform_set_drvdata(dev, pd);
560
561         res = platform_get_resource(dev, IORESOURCE_MEM, 0);
562         if (res == NULL) {
563                 dev_err(&dev->dev, "cannot find IO resource\n");
564                 ret = -ENOENT;
565                 goto err_irq;
566         }
567
568         size = (res->end - res->start) + 1;
569
570         pd->reg = ioremap(res->start, size);
571         if (pd->reg == NULL) {
572                 dev_err(&dev->dev, "cannot map IO\n");
573                 ret = -ENXIO;
574                 goto err_irq;
575         }
576
577         /* setup the private data */
578         adap = &pd->adap;
579         i2c_set_adapdata(adap, pd);
580
581         adap->owner = THIS_MODULE;
582         adap->algo = &sh_mobile_i2c_algorithm;
583         adap->dev.parent = &dev->dev;
584         adap->retries = 5;
585         adap->nr = dev->id;
586
587         strlcpy(adap->name, dev->name, sizeof(adap->name));
588
589         sh_mobile_i2c_setup_channel(dev);
590
591         ret = i2c_add_numbered_adapter(adap);
592         if (ret < 0) {
593                 dev_err(&dev->dev, "cannot add numbered adapter\n");
594                 goto err_all;
595         }
596
597         return 0;
598
599  err_all:
600         iounmap(pd->reg);
601  err_irq:
602         sh_mobile_i2c_hook_irqs(dev, 0);
603  err_clk:
604         clk_put(pd->clk);
605  err:
606         kfree(pd);
607         return ret;
608 }
609
610 static int sh_mobile_i2c_remove(struct platform_device *dev)
611 {
612         struct sh_mobile_i2c_data *pd = platform_get_drvdata(dev);
613
614         i2c_del_adapter(&pd->adap);
615         iounmap(pd->reg);
616         sh_mobile_i2c_hook_irqs(dev, 0);
617         clk_put(pd->clk);
618         kfree(pd);
619         return 0;
620 }
621
622 static struct platform_driver sh_mobile_i2c_driver = {
623         .driver         = {
624                 .name           = "i2c-sh_mobile",
625                 .owner          = THIS_MODULE,
626         },
627         .probe          = sh_mobile_i2c_probe,
628         .remove         = sh_mobile_i2c_remove,
629 };
630
631 static int __init sh_mobile_i2c_adap_init(void)
632 {
633         return platform_driver_register(&sh_mobile_i2c_driver);
634 }
635
636 static void __exit sh_mobile_i2c_adap_exit(void)
637 {
638         platform_driver_unregister(&sh_mobile_i2c_driver);
639 }
640
641 module_init(sh_mobile_i2c_adap_init);
642 module_exit(sh_mobile_i2c_adap_exit);
643
644 MODULE_DESCRIPTION("SuperH Mobile I2C Bus Controller driver");
645 MODULE_AUTHOR("Magnus Damm");
646 MODULE_LICENSE("GPL v2");