Merge commit 'origin/master' into next
[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         unsigned long i2c_clk;
164         u_int32_t num;
165         u_int32_t denom;
166         u_int32_t tmp;
167
168         /* Make sure the clock is enabled */
169         clk_enable(pd->clk);
170
171         /* Get clock rate after clock is enabled */
172         i2c_clk = clk_get_rate(pd->clk);
173
174         /* Calculate the value for iccl. From the data sheet:
175          * iccl = (p clock / transfer rate) * (L / (L + H))
176          * where L and H are the SCL low/high ratio (5/4 in this case).
177          * We also round off the result.
178          */
179         num = i2c_clk * 5;
180         denom = NORMAL_SPEED * 9;
181         tmp = num * 10 / denom;
182         if (tmp % 10 >= 5)
183                 pd->iccl = (u_int8_t)((num/denom) + 1);
184         else
185                 pd->iccl = (u_int8_t)(num/denom);
186
187         /* Calculate the value for icch. From the data sheet:
188            icch = (p clock / transfer rate) * (H / (L + H)) */
189         num = i2c_clk * 4;
190         tmp = num * 10 / denom;
191         if (tmp % 10 >= 5)
192                 pd->icch = (u_int8_t)((num/denom) + 1);
193         else
194                 pd->icch = (u_int8_t)(num/denom);
195
196         /* Enable channel and configure rx ack */
197         iowrite8(ioread8(ICCR(pd)) | ICCR_ICE, ICCR(pd));
198
199         /* Mask all interrupts */
200         iowrite8(0, ICIC(pd));
201
202         /* Set the clock */
203         iowrite8(pd->iccl, ICCL(pd));
204         iowrite8(pd->icch, ICCH(pd));
205 }
206
207 static void deactivate_ch(struct sh_mobile_i2c_data *pd)
208 {
209         /* Clear/disable interrupts */
210         iowrite8(0, ICSR(pd));
211         iowrite8(0, ICIC(pd));
212
213         /* Disable channel */
214         iowrite8(ioread8(ICCR(pd)) & ~ICCR_ICE, ICCR(pd));
215
216         /* Disable clock */
217         clk_disable(pd->clk);
218 }
219
220 static unsigned char i2c_op(struct sh_mobile_i2c_data *pd,
221                             enum sh_mobile_i2c_op op, unsigned char data)
222 {
223         unsigned char ret = 0;
224         unsigned long flags;
225
226         dev_dbg(pd->dev, "op %d, data in 0x%02x\n", op, data);
227
228         spin_lock_irqsave(&pd->lock, flags);
229
230         switch (op) {
231         case OP_START: /* issue start and trigger DTE interrupt */
232                 iowrite8(0x94, ICCR(pd));
233                 break;
234         case OP_TX_FIRST: /* disable DTE interrupt and write data */
235                 iowrite8(ICIC_WAITE | ICIC_ALE | ICIC_TACKE, ICIC(pd));
236                 iowrite8(data, ICDR(pd));
237                 break;
238         case OP_TX: /* write data */
239                 iowrite8(data, ICDR(pd));
240                 break;
241         case OP_TX_STOP: /* write data and issue a stop afterwards */
242                 iowrite8(data, ICDR(pd));
243                 iowrite8(0x90, ICCR(pd));
244                 break;
245         case OP_TX_TO_RX: /* select read mode */
246                 iowrite8(0x81, ICCR(pd));
247                 break;
248         case OP_RX: /* just read data */
249                 ret = ioread8(ICDR(pd));
250                 break;
251         case OP_RX_STOP: /* enable DTE interrupt, issue stop */
252                 iowrite8(ICIC_DTEE | ICIC_WAITE | ICIC_ALE | ICIC_TACKE,
253                          ICIC(pd));
254                 iowrite8(0xc0, ICCR(pd));
255                 break;
256         case OP_RX_STOP_DATA: /* enable DTE interrupt, read data, issue stop */
257                 iowrite8(ICIC_DTEE | ICIC_WAITE | ICIC_ALE | ICIC_TACKE,
258                          ICIC(pd));
259                 ret = ioread8(ICDR(pd));
260                 iowrite8(0xc0, ICCR(pd));
261                 break;
262         }
263
264         spin_unlock_irqrestore(&pd->lock, flags);
265
266         dev_dbg(pd->dev, "op %d, data out 0x%02x\n", op, ret);
267         return ret;
268 }
269
270 static int sh_mobile_i2c_is_first_byte(struct sh_mobile_i2c_data *pd)
271 {
272         if (pd->pos == -1)
273                 return 1;
274
275         return 0;
276 }
277
278 static int sh_mobile_i2c_is_last_byte(struct sh_mobile_i2c_data *pd)
279 {
280         if (pd->pos == (pd->msg->len - 1))
281                 return 1;
282
283         return 0;
284 }
285
286 static void sh_mobile_i2c_get_data(struct sh_mobile_i2c_data *pd,
287                                    unsigned char *buf)
288 {
289         switch (pd->pos) {
290         case -1:
291                 *buf = (pd->msg->addr & 0x7f) << 1;
292                 *buf |= (pd->msg->flags & I2C_M_RD) ? 1 : 0;
293                 break;
294         default:
295                 *buf = pd->msg->buf[pd->pos];
296         }
297 }
298
299 static int sh_mobile_i2c_isr_tx(struct sh_mobile_i2c_data *pd)
300 {
301         unsigned char data;
302
303         if (pd->pos == pd->msg->len)
304                 return 1;
305
306         sh_mobile_i2c_get_data(pd, &data);
307
308         if (sh_mobile_i2c_is_last_byte(pd))
309                 i2c_op(pd, OP_TX_STOP, data);
310         else if (sh_mobile_i2c_is_first_byte(pd))
311                 i2c_op(pd, OP_TX_FIRST, data);
312         else
313                 i2c_op(pd, OP_TX, data);
314
315         pd->pos++;
316         return 0;
317 }
318
319 static int sh_mobile_i2c_isr_rx(struct sh_mobile_i2c_data *pd)
320 {
321         unsigned char data;
322         int real_pos;
323
324         do {
325                 if (pd->pos <= -1) {
326                         sh_mobile_i2c_get_data(pd, &data);
327
328                         if (sh_mobile_i2c_is_first_byte(pd))
329                                 i2c_op(pd, OP_TX_FIRST, data);
330                         else
331                                 i2c_op(pd, OP_TX, data);
332                         break;
333                 }
334
335                 if (pd->pos == 0) {
336                         i2c_op(pd, OP_TX_TO_RX, 0);
337                         break;
338                 }
339
340                 real_pos = pd->pos - 2;
341
342                 if (pd->pos == pd->msg->len) {
343                         if (real_pos < 0) {
344                                 i2c_op(pd, OP_RX_STOP, 0);
345                                 break;
346                         }
347                         data = i2c_op(pd, OP_RX_STOP_DATA, 0);
348                 } else
349                         data = i2c_op(pd, OP_RX, 0);
350
351                 if (real_pos >= 0)
352                         pd->msg->buf[real_pos] = data;
353         } while (0);
354
355         pd->pos++;
356         return pd->pos == (pd->msg->len + 2);
357 }
358
359 static irqreturn_t sh_mobile_i2c_isr(int irq, void *dev_id)
360 {
361         struct platform_device *dev = dev_id;
362         struct sh_mobile_i2c_data *pd = platform_get_drvdata(dev);
363         unsigned char sr;
364         int wakeup;
365
366         sr = ioread8(ICSR(pd));
367         pd->sr |= sr; /* remember state */
368
369         dev_dbg(pd->dev, "i2c_isr 0x%02x 0x%02x %s %d %d!\n", sr, pd->sr,
370                (pd->msg->flags & I2C_M_RD) ? "read" : "write",
371                pd->pos, pd->msg->len);
372
373         if (sr & (ICSR_AL | ICSR_TACK)) {
374                 /* don't interrupt transaction - continue to issue stop */
375                 iowrite8(sr & ~(ICSR_AL | ICSR_TACK), ICSR(pd));
376                 wakeup = 0;
377         } else if (pd->msg->flags & I2C_M_RD)
378                 wakeup = sh_mobile_i2c_isr_rx(pd);
379         else
380                 wakeup = sh_mobile_i2c_isr_tx(pd);
381
382         if (sr & ICSR_WAIT) /* TODO: add delay here to support slow acks */
383                 iowrite8(sr & ~ICSR_WAIT, ICSR(pd));
384
385         if (wakeup) {
386                 pd->sr |= SW_DONE;
387                 wake_up(&pd->wait);
388         }
389
390         return IRQ_HANDLED;
391 }
392
393 static int start_ch(struct sh_mobile_i2c_data *pd, struct i2c_msg *usr_msg)
394 {
395         if (usr_msg->len == 0 && (usr_msg->flags & I2C_M_RD)) {
396                 dev_err(pd->dev, "Unsupported zero length i2c read\n");
397                 return -EIO;
398         }
399
400         /* Initialize channel registers */
401         iowrite8(ioread8(ICCR(pd)) & ~ICCR_ICE, ICCR(pd));
402
403         /* Enable channel and configure rx ack */
404         iowrite8(ioread8(ICCR(pd)) | ICCR_ICE, ICCR(pd));
405
406         /* Set the clock */
407         iowrite8(pd->iccl, ICCL(pd));
408         iowrite8(pd->icch, ICCH(pd));
409
410         pd->msg = usr_msg;
411         pd->pos = -1;
412         pd->sr = 0;
413
414         /* Enable all interrupts to begin with */
415         iowrite8(ICIC_WAITE | ICIC_ALE | ICIC_TACKE | ICIC_DTEE, ICIC(pd));
416         return 0;
417 }
418
419 static int sh_mobile_i2c_xfer(struct i2c_adapter *adapter,
420                               struct i2c_msg *msgs,
421                               int num)
422 {
423         struct sh_mobile_i2c_data *pd = i2c_get_adapdata(adapter);
424         struct i2c_msg  *msg;
425         int err = 0;
426         u_int8_t val;
427         int i, k, retry_count;
428
429         activate_ch(pd);
430
431         /* Process all messages */
432         for (i = 0; i < num; i++) {
433                 msg = &msgs[i];
434
435                 err = start_ch(pd, msg);
436                 if (err)
437                         break;
438
439                 i2c_op(pd, OP_START, 0);
440
441                 /* The interrupt handler takes care of the rest... */
442                 k = wait_event_timeout(pd->wait,
443                                        pd->sr & (ICSR_TACK | SW_DONE),
444                                        5 * HZ);
445                 if (!k)
446                         dev_err(pd->dev, "Transfer request timed out\n");
447
448                 retry_count = 1000;
449 again:
450                 val = ioread8(ICSR(pd));
451
452                 dev_dbg(pd->dev, "val 0x%02x pd->sr 0x%02x\n", val, pd->sr);
453
454                 /* the interrupt handler may wake us up before the
455                  * transfer is finished, so poll the hardware
456                  * until we're done.
457                  */
458                 if (val & ICSR_BUSY) {
459                         udelay(10);
460                         if (retry_count--)
461                                 goto again;
462
463                         err = -EIO;
464                         dev_err(pd->dev, "Polling timed out\n");
465                         break;
466                 }
467
468                 /* handle missing acknowledge and arbitration lost */
469                 if ((val | pd->sr) & (ICSR_TACK | ICSR_AL)) {
470                         err = -EIO;
471                         break;
472                 }
473         }
474
475         deactivate_ch(pd);
476
477         if (!err)
478                 err = num;
479         return err;
480 }
481
482 static u32 sh_mobile_i2c_func(struct i2c_adapter *adapter)
483 {
484         return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
485 }
486
487 static struct i2c_algorithm sh_mobile_i2c_algorithm = {
488         .functionality  = sh_mobile_i2c_func,
489         .master_xfer    = sh_mobile_i2c_xfer,
490 };
491
492 static int sh_mobile_i2c_hook_irqs(struct platform_device *dev, int hook)
493 {
494         struct resource *res;
495         int ret = -ENXIO;
496         int q, m;
497         int k = 0;
498         int n = 0;
499
500         while ((res = platform_get_resource(dev, IORESOURCE_IRQ, k))) {
501                 for (n = res->start; hook && n <= res->end; n++) {
502                         if (request_irq(n, sh_mobile_i2c_isr, IRQF_DISABLED,
503                                         dev_name(&dev->dev), dev))
504                                 goto rollback;
505                 }
506                 k++;
507         }
508
509         if (hook)
510                 return k > 0 ? 0 : -ENOENT;
511
512         k--;
513         ret = 0;
514
515  rollback:
516         for (q = k; k >= 0; k--) {
517                 for (m = n; m >= res->start; m--)
518                         free_irq(m, dev);
519
520                 res = platform_get_resource(dev, IORESOURCE_IRQ, k - 1);
521                 m = res->end;
522         }
523
524         return ret;
525 }
526
527 static int sh_mobile_i2c_probe(struct platform_device *dev)
528 {
529         struct sh_mobile_i2c_data *pd;
530         struct i2c_adapter *adap;
531         struct resource *res;
532         char clk_name[8];
533         int size;
534         int ret;
535
536         pd = kzalloc(sizeof(struct sh_mobile_i2c_data), GFP_KERNEL);
537         if (pd == NULL) {
538                 dev_err(&dev->dev, "cannot allocate private data\n");
539                 return -ENOMEM;
540         }
541
542         snprintf(clk_name, sizeof(clk_name), "i2c%d", dev->id);
543         pd->clk = clk_get(&dev->dev, clk_name);
544         if (IS_ERR(pd->clk)) {
545                 dev_err(&dev->dev, "cannot get clock \"%s\"\n", clk_name);
546                 ret = PTR_ERR(pd->clk);
547                 goto err;
548         }
549
550         ret = sh_mobile_i2c_hook_irqs(dev, 1);
551         if (ret) {
552                 dev_err(&dev->dev, "cannot request IRQ\n");
553                 goto err_clk;
554         }
555
556         pd->dev = &dev->dev;
557         platform_set_drvdata(dev, pd);
558
559         res = platform_get_resource(dev, IORESOURCE_MEM, 0);
560         if (res == NULL) {
561                 dev_err(&dev->dev, "cannot find IO resource\n");
562                 ret = -ENOENT;
563                 goto err_irq;
564         }
565
566         size = (res->end - res->start) + 1;
567
568         pd->reg = ioremap(res->start, size);
569         if (pd->reg == NULL) {
570                 dev_err(&dev->dev, "cannot map IO\n");
571                 ret = -ENXIO;
572                 goto err_irq;
573         }
574
575         /* setup the private data */
576         adap = &pd->adap;
577         i2c_set_adapdata(adap, pd);
578
579         adap->owner = THIS_MODULE;
580         adap->algo = &sh_mobile_i2c_algorithm;
581         adap->dev.parent = &dev->dev;
582         adap->retries = 5;
583         adap->nr = dev->id;
584
585         strlcpy(adap->name, dev->name, sizeof(adap->name));
586
587         spin_lock_init(&pd->lock);
588         init_waitqueue_head(&pd->wait);
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");