Merge master.kernel.org:/home/rmk/linux-2.6-arm
[linux-2.6] / drivers / i2c / busses / i2c-s3c2410.c
1 /* linux/drivers/i2c/busses/i2c-s3c2410.c
2  *
3  * Copyright (C) 2004,2005 Simtec Electronics
4  *      Ben Dooks <ben@simtec.co.uk>
5  *
6  * S3C2410 I2C Controller
7  *
8  * This program is free software; you can redistribute it and/or modify
9  * it under the terms of the GNU General Public License as published by
10  * the Free Software Foundation; either version 2 of the License, or
11  * (at your option) any later version.
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/config.h>
24 #include <linux/kernel.h>
25 #include <linux/module.h>
26
27 #include <linux/i2c.h>
28 #include <linux/i2c-id.h>
29 #include <linux/init.h>
30 #include <linux/time.h>
31 #include <linux/interrupt.h>
32 #include <linux/sched.h>
33 #include <linux/delay.h>
34 #include <linux/errno.h>
35 #include <linux/err.h>
36 #include <linux/device.h>
37
38 #include <asm/hardware.h>
39 #include <asm/irq.h>
40 #include <asm/io.h>
41
42 #include <asm/hardware/clock.h>
43 #include <asm/arch/regs-gpio.h>
44 #include <asm/arch/regs-iic.h>
45 #include <asm/arch/iic.h>
46
47 /* i2c controller state */
48
49 enum s3c24xx_i2c_state {
50         STATE_IDLE,
51         STATE_START,
52         STATE_READ,
53         STATE_WRITE,
54         STATE_STOP
55 };
56
57 struct s3c24xx_i2c {
58         spinlock_t              lock;
59         wait_queue_head_t       wait;
60
61         struct i2c_msg          *msg;
62         unsigned int            msg_num;
63         unsigned int            msg_idx;
64         unsigned int            msg_ptr;
65
66         enum s3c24xx_i2c_state  state;
67
68         void __iomem            *regs;
69         struct clk              *clk;
70         struct device           *dev;
71         struct resource         *irq;
72         struct resource         *ioarea;
73         struct i2c_adapter      adap;
74 };
75
76 /* default platform data to use if not supplied in the platform_device
77 */
78
79 static struct s3c2410_platform_i2c s3c24xx_i2c_default_platform = {
80         .flags          = 0,
81         .slave_addr     = 0x10,
82         .bus_freq       = 100*1000,
83         .max_freq       = 400*1000,
84         .sda_delay      = S3C2410_IICLC_SDA_DELAY5 | S3C2410_IICLC_FILTER_ON,
85 };
86
87 /* s3c24xx_i2c_is2440()
88  *
89  * return true is this is an s3c2440
90 */
91
92 static inline int s3c24xx_i2c_is2440(struct s3c24xx_i2c *i2c)
93 {
94         struct platform_device *pdev = to_platform_device(i2c->dev);
95
96         return !strcmp(pdev->name, "s3c2440-i2c");
97 }
98
99
100 /* s3c24xx_i2c_get_platformdata
101  *
102  * get the platform data associated with the given device, or return
103  * the default if there is none
104 */
105
106 static inline struct s3c2410_platform_i2c *s3c24xx_i2c_get_platformdata(struct device *dev)
107 {
108         if (dev->platform_data != NULL)
109                 return (struct s3c2410_platform_i2c *)dev->platform_data;
110
111         return &s3c24xx_i2c_default_platform;
112 }
113
114 /* s3c24xx_i2c_master_complete
115  *
116  * complete the message and wake up the caller, using the given return code,
117  * or zero to mean ok.
118 */
119
120 static inline void s3c24xx_i2c_master_complete(struct s3c24xx_i2c *i2c, int ret)
121 {
122         dev_dbg(i2c->dev, "master_complete %d\n", ret);
123
124         i2c->msg_ptr = 0;
125         i2c->msg = NULL;
126         i2c->msg_idx ++;
127         i2c->msg_num = 0;
128         if (ret)
129                 i2c->msg_idx = ret;
130
131         wake_up(&i2c->wait);
132 }
133
134 static inline void s3c24xx_i2c_disable_ack(struct s3c24xx_i2c *i2c)
135 {
136         unsigned long tmp;
137         
138         tmp = readl(i2c->regs + S3C2410_IICCON);
139         writel(tmp & ~S3C2410_IICCON_ACKEN, i2c->regs + S3C2410_IICCON);
140
141 }
142
143 static inline void s3c24xx_i2c_enable_ack(struct s3c24xx_i2c *i2c)
144 {
145         unsigned long tmp;
146         
147         tmp = readl(i2c->regs + S3C2410_IICCON);
148         writel(tmp | S3C2410_IICCON_ACKEN, i2c->regs + S3C2410_IICCON);
149
150 }
151
152 /* irq enable/disable functions */
153
154 static inline void s3c24xx_i2c_disable_irq(struct s3c24xx_i2c *i2c)
155 {
156         unsigned long tmp;
157         
158         tmp = readl(i2c->regs + S3C2410_IICCON);
159         writel(tmp & ~S3C2410_IICCON_IRQEN, i2c->regs + S3C2410_IICCON);
160 }
161
162 static inline void s3c24xx_i2c_enable_irq(struct s3c24xx_i2c *i2c)
163 {
164         unsigned long tmp;
165         
166         tmp = readl(i2c->regs + S3C2410_IICCON);
167         writel(tmp | S3C2410_IICCON_IRQEN, i2c->regs + S3C2410_IICCON);
168 }
169
170
171 /* s3c24xx_i2c_message_start
172  *
173  * put the start of a message onto the bus 
174 */
175
176 static void s3c24xx_i2c_message_start(struct s3c24xx_i2c *i2c, 
177                                       struct i2c_msg *msg)
178 {
179         unsigned int addr = (msg->addr & 0x7f) << 1;
180         unsigned long stat;
181         unsigned long iiccon;
182
183         stat = 0;
184         stat |=  S3C2410_IICSTAT_TXRXEN;
185
186         if (msg->flags & I2C_M_RD) {
187                 stat |= S3C2410_IICSTAT_MASTER_RX;
188                 addr |= 1;
189         } else
190                 stat |= S3C2410_IICSTAT_MASTER_TX;
191
192         if (msg->flags & I2C_M_REV_DIR_ADDR)
193                 addr ^= 1;
194
195         // todo - check for wether ack wanted or not
196         s3c24xx_i2c_enable_ack(i2c);
197
198         iiccon = readl(i2c->regs + S3C2410_IICCON);
199         writel(stat, i2c->regs + S3C2410_IICSTAT);
200         
201         dev_dbg(i2c->dev, "START: %08lx to IICSTAT, %02x to DS\n", stat, addr);
202         writeb(addr, i2c->regs + S3C2410_IICDS);
203         
204         // delay a bit and reset iiccon before setting start (per samsung)
205         udelay(1);
206         dev_dbg(i2c->dev, "iiccon, %08lx\n", iiccon);
207         writel(iiccon, i2c->regs + S3C2410_IICCON);
208         
209         stat |=  S3C2410_IICSTAT_START;
210         writel(stat, i2c->regs + S3C2410_IICSTAT);
211 }
212
213 static inline void s3c24xx_i2c_stop(struct s3c24xx_i2c *i2c, int ret)
214 {
215         unsigned long iicstat = readl(i2c->regs + S3C2410_IICSTAT);
216
217         dev_dbg(i2c->dev, "STOP\n");
218
219         /* stop the transfer */
220         iicstat &= ~ S3C2410_IICSTAT_START;
221         writel(iicstat, i2c->regs + S3C2410_IICSTAT);
222         
223         i2c->state = STATE_STOP;
224         
225         s3c24xx_i2c_master_complete(i2c, ret);
226         s3c24xx_i2c_disable_irq(i2c);
227 }
228
229 /* helper functions to determine the current state in the set of
230  * messages we are sending */
231
232 /* is_lastmsg()
233  *
234  * returns TRUE if the current message is the last in the set 
235 */
236
237 static inline int is_lastmsg(struct s3c24xx_i2c *i2c)
238 {
239         return i2c->msg_idx >= (i2c->msg_num - 1);
240 }
241
242 /* is_msglast
243  *
244  * returns TRUE if we this is the last byte in the current message
245 */
246
247 static inline int is_msglast(struct s3c24xx_i2c *i2c)
248 {
249         return i2c->msg_ptr == i2c->msg->len-1;
250 }
251
252 /* is_msgend
253  *
254  * returns TRUE if we reached the end of the current message
255 */
256
257 static inline int is_msgend(struct s3c24xx_i2c *i2c)
258 {
259         return i2c->msg_ptr >= i2c->msg->len;
260 }
261
262 /* i2s_s3c_irq_nextbyte
263  *
264  * process an interrupt and work out what to do
265  */
266
267 static int i2s_s3c_irq_nextbyte(struct s3c24xx_i2c *i2c, unsigned long iicstat)
268 {
269         unsigned long tmp;
270         unsigned char byte;
271         int ret = 0;
272
273         switch (i2c->state) {
274
275         case STATE_IDLE:
276                 dev_err(i2c->dev, "%s: called in STATE_IDLE\n", __FUNCTION__);
277                 goto out;
278                 break;
279
280         case STATE_STOP:
281                 dev_err(i2c->dev, "%s: called in STATE_STOP\n", __FUNCTION__);
282                 s3c24xx_i2c_disable_irq(i2c);           
283                 goto out_ack;
284
285         case STATE_START:
286                 /* last thing we did was send a start condition on the
287                  * bus, or started a new i2c message
288                  */
289                 
290                 if (iicstat  & S3C2410_IICSTAT_LASTBIT &&
291                     !(i2c->msg->flags & I2C_M_IGNORE_NAK)) {
292                         /* ack was not received... */
293
294                         dev_dbg(i2c->dev, "ack was not received\n");
295                         s3c24xx_i2c_stop(i2c, -EREMOTEIO);
296                         goto out_ack;
297                 }
298
299                 if (i2c->msg->flags & I2C_M_RD)
300                         i2c->state = STATE_READ;
301                 else
302                         i2c->state = STATE_WRITE;
303
304                 /* terminate the transfer if there is nothing to do
305                  * (used by the i2c probe to find devices */
306
307                 if (is_lastmsg(i2c) && i2c->msg->len == 0) {
308                         s3c24xx_i2c_stop(i2c, 0);
309                         goto out_ack;
310                 }
311
312                 if (i2c->state == STATE_READ)
313                         goto prepare_read;
314
315                 /* fall through to the write state, as we will need to 
316                  * send a byte as well */
317
318         case STATE_WRITE:
319                 /* we are writing data to the device... check for the
320                  * end of the message, and if so, work out what to do
321                  */
322
323         retry_write:
324                 if (!is_msgend(i2c)) {
325                         byte = i2c->msg->buf[i2c->msg_ptr++];
326                         writeb(byte, i2c->regs + S3C2410_IICDS);
327                         
328                 } else if (!is_lastmsg(i2c)) {
329                         /* we need to go to the next i2c message */
330
331                         dev_dbg(i2c->dev, "WRITE: Next Message\n");
332
333                         i2c->msg_ptr = 0;
334                         i2c->msg_idx ++;
335                         i2c->msg++;
336                         
337                         /* check to see if we need to do another message */
338                         if (i2c->msg->flags & I2C_M_NOSTART) {
339
340                                 if (i2c->msg->flags & I2C_M_RD) {
341                                         /* cannot do this, the controller
342                                          * forces us to send a new START
343                                          * when we change direction */
344
345                                         s3c24xx_i2c_stop(i2c, -EINVAL);
346                                 }
347
348                                 goto retry_write;
349                         } else {
350                         
351                                 /* send the new start */
352                                 s3c24xx_i2c_message_start(i2c, i2c->msg);
353                                 i2c->state = STATE_START;
354                         }
355
356                 } else {
357                         /* send stop */
358
359                         s3c24xx_i2c_stop(i2c, 0);
360                 }
361                 break;
362
363         case STATE_READ:
364                 /* we have a byte of data in the data register, do 
365                  * something with it, and then work out wether we are
366                  * going to do any more read/write
367                  */
368
369                 if (!(i2c->msg->flags & I2C_M_IGNORE_NAK) &&
370                     !(is_msglast(i2c) && is_lastmsg(i2c))) {
371
372                         if (iicstat & S3C2410_IICSTAT_LASTBIT) {
373                                 dev_dbg(i2c->dev, "READ: No Ack\n");
374
375                                 s3c24xx_i2c_stop(i2c, -ECONNREFUSED);
376                                 goto out_ack;
377                         }
378                 }
379
380                 byte = readb(i2c->regs + S3C2410_IICDS);
381                 i2c->msg->buf[i2c->msg_ptr++] = byte;
382
383         prepare_read:
384                 if (is_msglast(i2c)) {
385                         /* last byte of buffer */
386
387                         if (is_lastmsg(i2c))
388                                 s3c24xx_i2c_disable_ack(i2c);
389                         
390                 } else if (is_msgend(i2c)) {
391                         /* ok, we've read the entire buffer, see if there
392                          * is anything else we need to do */
393
394                         if (is_lastmsg(i2c)) {
395                                 /* last message, send stop and complete */
396                                 dev_dbg(i2c->dev, "READ: Send Stop\n");
397
398                                 s3c24xx_i2c_stop(i2c, 0);
399                         } else {
400                                 /* go to the next transfer */
401                                 dev_dbg(i2c->dev, "READ: Next Transfer\n");
402
403                                 i2c->msg_ptr = 0;
404                                 i2c->msg_idx++;
405                                 i2c->msg++;
406                         }
407                 }
408
409                 break;
410         }
411
412         /* acknowlegde the IRQ and get back on with the work */
413
414  out_ack:
415         tmp = readl(i2c->regs + S3C2410_IICCON);        
416         tmp &= ~S3C2410_IICCON_IRQPEND;
417         writel(tmp, i2c->regs + S3C2410_IICCON);
418  out:
419         return ret;
420 }
421
422 /* s3c24xx_i2c_irq
423  *
424  * top level IRQ servicing routine
425 */
426
427 static irqreturn_t s3c24xx_i2c_irq(int irqno, void *dev_id,
428                                    struct pt_regs *regs)
429 {
430         struct s3c24xx_i2c *i2c = dev_id;
431         unsigned long status;
432         unsigned long tmp;
433
434         status = readl(i2c->regs + S3C2410_IICSTAT);
435
436         if (status & S3C2410_IICSTAT_ARBITR) {
437                 // deal with arbitration loss
438                 dev_err(i2c->dev, "deal with arbitration loss\n");
439         }
440
441         if (i2c->state == STATE_IDLE) {
442                 dev_dbg(i2c->dev, "IRQ: error i2c->state == IDLE\n");
443
444                 tmp = readl(i2c->regs + S3C2410_IICCON);        
445                 tmp &= ~S3C2410_IICCON_IRQPEND;
446                 writel(tmp, i2c->regs +  S3C2410_IICCON);
447                 goto out;
448         }
449         
450         /* pretty much this leaves us with the fact that we've
451          * transmitted or received whatever byte we last sent */
452
453         i2s_s3c_irq_nextbyte(i2c, status);
454
455  out:
456         return IRQ_HANDLED;
457 }
458
459
460 /* s3c24xx_i2c_set_master
461  *
462  * get the i2c bus for a master transaction
463 */
464
465 static int s3c24xx_i2c_set_master(struct s3c24xx_i2c *i2c)
466 {
467         unsigned long iicstat;
468         int timeout = 400;
469
470         while (timeout-- > 0) {
471                 iicstat = readl(i2c->regs + S3C2410_IICSTAT);
472                 
473                 if (!(iicstat & S3C2410_IICSTAT_BUSBUSY))
474                         return 0;
475
476                 msleep(1);
477         }
478
479         dev_dbg(i2c->dev, "timeout: GPEDAT is %08x\n",
480                 __raw_readl(S3C2410_GPEDAT));
481
482         return -ETIMEDOUT;
483 }
484
485 /* s3c24xx_i2c_doxfer
486  *
487  * this starts an i2c transfer
488 */
489
490 static int s3c24xx_i2c_doxfer(struct s3c24xx_i2c *i2c, struct i2c_msg *msgs, int num)
491 {
492         unsigned long timeout;
493         int ret;
494
495         ret = s3c24xx_i2c_set_master(i2c);
496         if (ret != 0) {
497                 dev_err(i2c->dev, "cannot get bus (error %d)\n", ret);
498                 ret = -EAGAIN;
499                 goto out;
500         }
501
502         spin_lock_irq(&i2c->lock);
503
504         i2c->msg     = msgs;
505         i2c->msg_num = num;
506         i2c->msg_ptr = 0;
507         i2c->msg_idx = 0;
508         i2c->state   = STATE_START;
509
510         s3c24xx_i2c_enable_irq(i2c);
511         s3c24xx_i2c_message_start(i2c, msgs);
512         spin_unlock_irq(&i2c->lock);
513         
514         timeout = wait_event_timeout(i2c->wait, i2c->msg_num == 0, HZ * 5);
515
516         ret = i2c->msg_idx;
517
518         /* having these next two as dev_err() makes life very 
519          * noisy when doing an i2cdetect */
520
521         if (timeout == 0)
522                 dev_dbg(i2c->dev, "timeout\n");
523         else if (ret != num)
524                 dev_dbg(i2c->dev, "incomplete xfer (%d)\n", ret);
525
526         /* ensure the stop has been through the bus */
527
528         msleep(1);
529
530  out:
531         return ret;
532 }
533
534 /* s3c24xx_i2c_xfer
535  *
536  * first port of call from the i2c bus code when an message needs
537  * transferring across the i2c bus.
538 */
539
540 static int s3c24xx_i2c_xfer(struct i2c_adapter *adap,
541                         struct i2c_msg *msgs, int num)
542 {
543         struct s3c24xx_i2c *i2c = (struct s3c24xx_i2c *)adap->algo_data;
544         int retry;
545         int ret;
546
547         for (retry = 0; retry < adap->retries; retry++) {
548
549                 ret = s3c24xx_i2c_doxfer(i2c, msgs, num);
550
551                 if (ret != -EAGAIN)
552                         return ret;
553
554                 dev_dbg(i2c->dev, "Retrying transmission (%d)\n", retry);
555
556                 udelay(100);
557         }
558
559         return -EREMOTEIO;
560 }
561
562 /* declare our i2c functionality */
563 static u32 s3c24xx_i2c_func(struct i2c_adapter *adap)
564 {
565         return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_PROTOCOL_MANGLING;
566 }
567
568 /* i2c bus registration info */
569
570 static struct i2c_algorithm s3c24xx_i2c_algorithm = {
571         .name                   = "S3C2410-I2C-Algorithm",
572         .master_xfer            = s3c24xx_i2c_xfer,
573         .functionality          = s3c24xx_i2c_func,
574 };
575
576 static struct s3c24xx_i2c s3c24xx_i2c = {
577         .lock   = SPIN_LOCK_UNLOCKED,
578         .wait   = __WAIT_QUEUE_HEAD_INITIALIZER(s3c24xx_i2c.wait),
579         .adap   = {
580                 .name                   = "s3c2410-i2c",
581                 .owner                  = THIS_MODULE,
582                 .algo                   = &s3c24xx_i2c_algorithm,
583                 .retries                = 2,
584                 .class                  = I2C_CLASS_HWMON,
585         },
586 };
587
588 /* s3c24xx_i2c_calcdivisor
589  *
590  * return the divisor settings for a given frequency
591 */
592
593 static int s3c24xx_i2c_calcdivisor(unsigned long clkin, unsigned int wanted,
594                                    unsigned int *div1, unsigned int *divs)
595 {
596         unsigned int calc_divs = clkin / wanted;
597         unsigned int calc_div1;
598
599         if (calc_divs > (16*16))
600                 calc_div1 = 512;
601         else
602                 calc_div1 = 16;
603
604         calc_divs += calc_div1-1;
605         calc_divs /= calc_div1;
606
607         if (calc_divs == 0)
608                 calc_divs = 1;
609         if (calc_divs > 17)
610                 calc_divs = 17;
611
612         *divs = calc_divs;
613         *div1 = calc_div1;
614
615         return clkin / (calc_divs * calc_div1);
616 }
617
618 /* freq_acceptable
619  *
620  * test wether a frequency is within the acceptable range of error
621 */
622
623 static inline int freq_acceptable(unsigned int freq, unsigned int wanted)
624 {
625         int diff = freq - wanted;
626
627         return (diff >= -2 && diff <= 2);
628 }
629
630 /* s3c24xx_i2c_getdivisor
631  *
632  * work out a divisor for the user requested frequency setting,
633  * either by the requested frequency, or scanning the acceptable
634  * range of frequencies until something is found
635 */
636
637 static int s3c24xx_i2c_getdivisor(struct s3c24xx_i2c *i2c,
638                                   struct s3c2410_platform_i2c *pdata,
639                                   unsigned long *iicon,
640                                   unsigned int *got)
641 {
642         unsigned long clkin = clk_get_rate(i2c->clk);
643         
644         unsigned int divs, div1;
645         int freq;
646         int start, end;
647
648         clkin /= 1000;          /* clkin now in KHz */
649      
650         dev_dbg(i2c->dev,  "pdata %p, freq %lu %lu..%lu\n",
651                  pdata, pdata->bus_freq, pdata->min_freq, pdata->max_freq);
652
653         if (pdata->bus_freq != 0) {
654                 freq = s3c24xx_i2c_calcdivisor(clkin, pdata->bus_freq/1000,
655                                                &div1, &divs);
656                 if (freq_acceptable(freq, pdata->bus_freq/1000))
657                         goto found;
658         }
659
660         /* ok, we may have to search for something suitable... */
661
662         start = (pdata->max_freq == 0) ? pdata->bus_freq : pdata->max_freq;
663         end = pdata->min_freq;
664
665         start /= 1000;
666         end /= 1000;
667
668         /* search loop... */
669
670         for (; start > end; start--) {
671                 freq = s3c24xx_i2c_calcdivisor(clkin, start, &div1, &divs);
672                 if (freq_acceptable(freq, start))
673                         goto found;
674         }
675
676         /* cannot find frequency spec */
677
678         return -EINVAL;
679
680  found:
681         *got = freq;
682         *iicon |= (divs-1);
683         *iicon |= (div1 == 512) ? S3C2410_IICCON_TXDIV_512 : 0;
684         return 0;
685 }
686
687 /* s3c24xx_i2c_init
688  *
689  * initialise the controller, set the IO lines and frequency 
690 */
691
692 static int s3c24xx_i2c_init(struct s3c24xx_i2c *i2c)
693 {
694         unsigned long iicon = S3C2410_IICCON_IRQEN | S3C2410_IICCON_ACKEN;
695         struct s3c2410_platform_i2c *pdata;
696         unsigned int freq;
697
698         /* get the plafrom data */
699
700         pdata = s3c24xx_i2c_get_platformdata(i2c->adap.dev.parent);
701
702         /* inititalise the gpio */
703
704         s3c2410_gpio_cfgpin(S3C2410_GPE15, S3C2410_GPE15_IICSDA);
705         s3c2410_gpio_cfgpin(S3C2410_GPE14, S3C2410_GPE14_IICSCL);
706
707         /* write slave address */
708         
709         writeb(pdata->slave_addr, i2c->regs + S3C2410_IICADD);
710
711         dev_info(i2c->dev, "slave address 0x%02x\n", pdata->slave_addr);
712
713         /* we need to work out the divisors for the clock... */
714
715         if (s3c24xx_i2c_getdivisor(i2c, pdata, &iicon, &freq) != 0) {
716                 dev_err(i2c->dev, "cannot meet bus frequency required\n");
717                 return -EINVAL;
718         }
719
720         /* todo - check that the i2c lines aren't being dragged anywhere */
721
722         dev_info(i2c->dev, "bus frequency set to %d KHz\n", freq);
723         dev_dbg(i2c->dev, "S3C2410_IICCON=0x%02lx\n", iicon);
724         
725         writel(iicon, i2c->regs + S3C2410_IICCON);
726
727         /* check for s3c2440 i2c controller  */
728
729         if (s3c24xx_i2c_is2440(i2c)) {
730                 dev_dbg(i2c->dev, "S3C2440_IICLC=%08x\n", pdata->sda_delay);
731
732                 writel(pdata->sda_delay, i2c->regs + S3C2440_IICLC);
733         }
734
735         return 0;
736 }
737
738 static void s3c24xx_i2c_free(struct s3c24xx_i2c *i2c)
739 {
740         if (i2c->clk != NULL && !IS_ERR(i2c->clk)) {
741                 clk_disable(i2c->clk);
742                 clk_unuse(i2c->clk);
743                 clk_put(i2c->clk);
744                 i2c->clk = NULL;
745         }
746
747         if (i2c->regs != NULL) {
748                 iounmap(i2c->regs);
749                 i2c->regs = NULL;
750         }
751
752         if (i2c->ioarea != NULL) {
753                 release_resource(i2c->ioarea);
754                 kfree(i2c->ioarea);
755                 i2c->ioarea = NULL;
756         }
757 }
758
759 /* s3c24xx_i2c_probe
760  *
761  * called by the bus driver when a suitable device is found
762 */
763
764 static int s3c24xx_i2c_probe(struct device *dev)
765 {
766         struct platform_device *pdev = to_platform_device(dev);
767         struct s3c24xx_i2c *i2c = &s3c24xx_i2c;
768         struct resource *res;
769         int ret;
770
771         /* find the clock and enable it */
772
773         i2c->dev = dev;
774         i2c->clk = clk_get(dev, "i2c");
775         if (IS_ERR(i2c->clk)) {
776                 dev_err(dev, "cannot get clock\n");
777                 ret = -ENOENT;
778                 goto out;
779         }
780
781         dev_dbg(dev, "clock source %p\n", i2c->clk);
782
783         clk_use(i2c->clk);
784         clk_enable(i2c->clk);
785
786         /* map the registers */
787
788         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
789         if (res == NULL) {
790                 dev_err(dev, "cannot find IO resource\n");
791                 ret = -ENOENT;
792                 goto out;
793         }
794
795         i2c->ioarea = request_mem_region(res->start, (res->end-res->start)+1,
796                                          pdev->name);
797
798         if (i2c->ioarea == NULL) {
799                 dev_err(dev, "cannot request IO\n");
800                 ret = -ENXIO;
801                 goto out;
802         }
803
804         i2c->regs = ioremap(res->start, (res->end-res->start)+1);
805
806         if (i2c->regs == NULL) {
807                 dev_err(dev, "cannot map IO\n");
808                 ret = -ENXIO;
809                 goto out;
810         }
811
812         dev_dbg(dev, "registers %p (%p, %p)\n", i2c->regs, i2c->ioarea, res);
813
814         /* setup info block for the i2c core */
815
816         i2c->adap.algo_data = i2c;
817         i2c->adap.dev.parent = dev;
818
819         /* initialise the i2c controller */
820
821         ret = s3c24xx_i2c_init(i2c);
822         if (ret != 0)
823                 goto out;
824
825         /* find the IRQ for this unit (note, this relies on the init call to
826          * ensure no current IRQs pending 
827          */
828
829         res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
830         if (res == NULL) {
831                 dev_err(dev, "cannot find IRQ\n");
832                 ret = -ENOENT;
833                 goto out;
834         }
835
836         ret = request_irq(res->start, s3c24xx_i2c_irq, SA_INTERRUPT,
837                           pdev->name, i2c);
838
839         if (ret != 0) {
840                 dev_err(dev, "cannot claim IRQ\n");
841                 goto out;
842         }
843
844         i2c->irq = res;
845                 
846         dev_dbg(dev, "irq resource %p (%ld)\n", res, res->start);
847
848         ret = i2c_add_adapter(&i2c->adap);
849         if (ret < 0) {
850                 dev_err(dev, "failed to add bus to i2c core\n");
851                 goto out;
852         }
853
854         dev_set_drvdata(dev, i2c);
855
856         dev_info(dev, "%s: S3C I2C adapter\n", i2c->adap.dev.bus_id);
857
858  out:
859         if (ret < 0)
860                 s3c24xx_i2c_free(i2c);
861
862         return ret;
863 }
864
865 /* s3c24xx_i2c_remove
866  *
867  * called when device is removed from the bus
868 */
869
870 static int s3c24xx_i2c_remove(struct device *dev)
871 {
872         struct s3c24xx_i2c *i2c = dev_get_drvdata(dev);
873         
874         if (i2c != NULL) {
875                 s3c24xx_i2c_free(i2c);
876                 dev_set_drvdata(dev, NULL);
877         }
878
879         return 0;
880 }
881
882 #ifdef CONFIG_PM
883 static int s3c24xx_i2c_resume(struct device *dev, u32 level)
884 {
885         struct s3c24xx_i2c *i2c = dev_get_drvdata(dev);
886         
887         if (i2c != NULL && level == RESUME_ENABLE) {
888                 dev_dbg(dev, "resume: level %d\n", level);
889                 s3c24xx_i2c_init(i2c);
890         }
891
892         return 0;
893 }
894
895 #else
896 #define s3c24xx_i2c_resume NULL
897 #endif
898
899 /* device driver for platform bus bits */
900
901 static struct device_driver s3c2410_i2c_driver = {
902         .name           = "s3c2410-i2c",
903         .bus            = &platform_bus_type,
904         .probe          = s3c24xx_i2c_probe,
905         .remove         = s3c24xx_i2c_remove,
906         .resume         = s3c24xx_i2c_resume,
907 };
908
909 static struct device_driver s3c2440_i2c_driver = {
910         .name           = "s3c2440-i2c",
911         .bus            = &platform_bus_type,
912         .probe          = s3c24xx_i2c_probe,
913         .remove         = s3c24xx_i2c_remove,
914         .resume         = s3c24xx_i2c_resume,
915 };
916
917 static int __init i2c_adap_s3c_init(void)
918 {
919         int ret;
920
921         ret = driver_register(&s3c2410_i2c_driver);
922         if (ret == 0)
923                 ret = driver_register(&s3c2440_i2c_driver); 
924
925         return ret;
926 }
927
928 static void __exit i2c_adap_s3c_exit(void)
929 {
930         driver_unregister(&s3c2410_i2c_driver);
931         driver_unregister(&s3c2440_i2c_driver);
932 }
933
934 module_init(i2c_adap_s3c_init);
935 module_exit(i2c_adap_s3c_exit);
936
937 MODULE_DESCRIPTION("S3C24XX I2C Bus driver");
938 MODULE_AUTHOR("Ben Dooks, <ben@simtec.co.uk>");
939 MODULE_LICENSE("GPL");