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Linux 3.3-rc6
[linux/fpc-iii.git] / drivers / i2c / busses / i2c-sh7760.c
blobc0c9dffbdb12faa38fded2cfdae970dc941c91c5
1 /*
2 * I2C bus driver for the SH7760 I2C Interfaces.
3 *
4 * (c) 2005-2008 MSC Vertriebsges.m.b.H, Manuel Lauss <mlau@msc-ge.com>
5 *
6 * licensed under the terms outlined in the file COPYING.
7 *
8 */
9
10 #include <linux/completion.h>
11 #include <linux/delay.h>
12 #include <linux/err.h>
13 #include <linux/i2c.h>
14 #include <linux/init.h>
15 #include <linux/interrupt.h>
16 #include <linux/ioport.h>
17 #include <linux/platform_device.h>
18 #include <linux/slab.h>
19 #include <linux/io.h>
20 #include <linux/module.h>
21
22 #include <asm/clock.h>
23 #include <asm/i2c-sh7760.h>
24
25 /* register offsets */
26 #define I2CSCR 0x0 /* slave ctrl */
27 #define I2CMCR 0x4 /* master ctrl */
28 #define I2CSSR 0x8 /* slave status */
29 #define I2CMSR 0xC /* master status */
30 #define I2CSIER 0x10 /* slave irq enable */
31 #define I2CMIER 0x14 /* master irq enable */
32 #define I2CCCR 0x18 /* clock dividers */
33 #define I2CSAR 0x1c /* slave address */
34 #define I2CMAR 0x20 /* master address */
35 #define I2CRXTX 0x24 /* data port */
36 #define I2CFCR 0x28 /* fifo control */
37 #define I2CFSR 0x2C /* fifo status */
38 #define I2CFIER 0x30 /* fifo irq enable */
39 #define I2CRFDR 0x34 /* rx fifo count */
40 #define I2CTFDR 0x38 /* tx fifo count */
41
42 #define REGSIZE 0x3C
43
44 #define MCR_MDBS 0x80 /* non-fifo mode switch */
45 #define MCR_FSCL 0x40 /* override SCL pin */
46 #define MCR_FSDA 0x20 /* override SDA pin */
47 #define MCR_OBPC 0x10 /* override pins */
48 #define MCR_MIE 0x08 /* master if enable */
49 #define MCR_TSBE 0x04
50 #define MCR_FSB 0x02 /* force stop bit */
51 #define MCR_ESG 0x01 /* en startbit gen. */
52
53 #define MSR_MNR 0x40 /* nack received */
54 #define MSR_MAL 0x20 /* arbitration lost */
55 #define MSR_MST 0x10 /* sent a stop */
56 #define MSR_MDE 0x08
57 #define MSR_MDT 0x04
58 #define MSR_MDR 0x02
59 #define MSR_MAT 0x01 /* slave addr xfer done */
60
61 #define MIE_MNRE 0x40 /* nack irq en */
62 #define MIE_MALE 0x20 /* arblos irq en */
63 #define MIE_MSTE 0x10 /* stop irq en */
64 #define MIE_MDEE 0x08
65 #define MIE_MDTE 0x04
66 #define MIE_MDRE 0x02
67 #define MIE_MATE 0x01 /* address sent irq en */
68
69 #define FCR_RFRST 0x02 /* reset rx fifo */
70 #define FCR_TFRST 0x01 /* reset tx fifo */
71
72 #define FSR_TEND 0x04 /* last byte sent */
73 #define FSR_RDF 0x02 /* rx fifo trigger */
74 #define FSR_TDFE 0x01 /* tx fifo empty */
75
76 #define FIER_TEIE 0x04 /* tx fifo empty irq en */
77 #define FIER_RXIE 0x02 /* rx fifo trig irq en */
78 #define FIER_TXIE 0x01 /* tx fifo trig irq en */
79
80 #define FIFO_SIZE 16
81
82 struct cami2c {
83 void __iomem *iobase;
84 struct i2c_adapter adap;
85
86 /* message processing */
87 struct i2c_msg *msg;
88 #define IDF_SEND 1
89 #define IDF_RECV 2
90 #define IDF_STOP 4
91 int flags;
92
93 #define IDS_DONE 1
94 #define IDS_ARBLOST 2
95 #define IDS_NACK 4
96 int status;
97 struct completion xfer_done;
98
99 int irq;
100 struct resource *ioarea;
101 };
102
103 static inline void OUT32(struct cami2c *cam, int reg, unsigned long val)
104 {
105 __raw_writel(val, (unsigned long)cam->iobase + reg);
106 }
107
108 static inline unsigned long IN32(struct cami2c *cam, int reg)
109 {
110 return __raw_readl((unsigned long)cam->iobase + reg);
111 }
112
113 static irqreturn_t sh7760_i2c_irq(int irq, void *ptr)
114 {
115 struct cami2c *id = ptr;
116 struct i2c_msg *msg = id->msg;
117 char *data = msg->buf;
118 unsigned long msr, fsr, fier, len;
119
120 msr = IN32(id, I2CMSR);
121 fsr = IN32(id, I2CFSR);
122
123 /* arbitration lost */
124 if (msr & MSR_MAL) {
125 OUT32(id, I2CMCR, 0);
126 OUT32(id, I2CSCR, 0);
127 OUT32(id, I2CSAR, 0);
128 id->status |= IDS_DONE | IDS_ARBLOST;
129 goto out;
130 }
131
132 if (msr & MSR_MNR) {
133 /* NACK handling is very screwed up. After receiving a
134 * NAK IRQ one has to wait a bit before writing to any
135 * registers, or the ctl will lock up. After that delay
136 * do a normal i2c stop. Then wait at least 1 ms before
137 * attempting another transfer or ctl will stop working
138 */
139 udelay(100); /* wait or risk ctl hang */
140 OUT32(id, I2CFCR, FCR_RFRST | FCR_TFRST);
141 OUT32(id, I2CMCR, MCR_MIE | MCR_FSB);
142 OUT32(id, I2CFIER, 0);
143 OUT32(id, I2CMIER, MIE_MSTE);
144 OUT32(id, I2CSCR, 0);
145 OUT32(id, I2CSAR, 0);
146 id->status |= IDS_NACK;
147 msr &= ~MSR_MAT;
148 fsr = 0;
149 /* In some cases the MST bit is also set. */
150 }
151
152 /* i2c-stop was sent */
153 if (msr & MSR_MST) {
154 id->status |= IDS_DONE;
155 goto out;
156 }
157
158 /* i2c slave addr was sent; set to "normal" operation */
159 if (msr & MSR_MAT)
160 OUT32(id, I2CMCR, MCR_MIE);
161
162 fier = IN32(id, I2CFIER);
163
164 if (fsr & FSR_RDF) {
165 len = IN32(id, I2CRFDR);
166 if (msg->len <= len) {
167 if (id->flags & IDF_STOP) {
168 OUT32(id, I2CMCR, MCR_MIE | MCR_FSB);
169 OUT32(id, I2CFIER, 0);
170 /* manual says: wait >= 0.5 SCL times */
171 udelay(5);
172 /* next int should be MST */
173 } else {
174 id->status |= IDS_DONE;
175 /* keep the RDF bit: ctrl holds SCL low
176 * until the setup for the next i2c_msg
177 * clears this bit.
178 */
179 fsr &= ~FSR_RDF;
180 }
181 }
182 while (msg->len && len) {
183 *data++ = IN32(id, I2CRXTX);
184 msg->len--;
185 len--;
186 }
187
188 if (msg->len) {
189 len = (msg->len >= FIFO_SIZE) ? FIFO_SIZE - 1
190 : msg->len - 1;
191
192 OUT32(id, I2CFCR, FCR_TFRST | ((len & 0xf) << 4));
193 }
194
195 } else if (id->flags & IDF_SEND) {
196 if ((fsr & FSR_TEND) && (msg->len < 1)) {
197 if (id->flags & IDF_STOP) {
198 OUT32(id, I2CMCR, MCR_MIE | MCR_FSB);
199 } else {
200 id->status |= IDS_DONE;
201 /* keep the TEND bit: ctl holds SCL low
202 * until the setup for the next i2c_msg
203 * clears this bit.
204 */
205 fsr &= ~FSR_TEND;
206 }
207 }
208 if (fsr & FSR_TDFE) {
209 while (msg->len && (IN32(id, I2CTFDR) < FIFO_SIZE)) {
210 OUT32(id, I2CRXTX, *data++);
211 msg->len--;
212 }
213
214 if (msg->len < 1) {
215 fier &= ~FIER_TXIE;
216 OUT32(id, I2CFIER, fier);
217 } else {
218 len = (msg->len >= FIFO_SIZE) ? 2 : 0;
219 OUT32(id, I2CFCR,
220 FCR_RFRST | ((len & 3) << 2));
221 }
222 }
223 }
224 out:
225 if (id->status & IDS_DONE) {
226 OUT32(id, I2CMIER, 0);
227 OUT32(id, I2CFIER, 0);
228 id->msg = NULL;
229 complete(&id->xfer_done);
230 }
231 /* clear status flags and ctrl resumes work */
232 OUT32(id, I2CMSR, ~msr);
233 OUT32(id, I2CFSR, ~fsr);
234 OUT32(id, I2CSSR, 0);
235
236 return IRQ_HANDLED;
237 }
238
239
240 /* prepare and start a master receive operation */
241 static void sh7760_i2c_mrecv(struct cami2c *id)
242 {
243 int len;
244
245 id->flags |= IDF_RECV;
246
247 /* set the slave addr reg; otherwise rcv wont work! */
248 OUT32(id, I2CSAR, 0xfe);
249 OUT32(id, I2CMAR, (id->msg->addr << 1) | 1);
250
251 /* adjust rx fifo trigger */
252 if (id->msg->len >= FIFO_SIZE)
253 len = FIFO_SIZE - 1; /* trigger at fifo full */
254 else
255 len = id->msg->len - 1; /* trigger before all received */
256
257 OUT32(id, I2CFCR, FCR_RFRST | FCR_TFRST);
258 OUT32(id, I2CFCR, FCR_TFRST | ((len & 0xF) << 4));
259
260 OUT32(id, I2CMSR, 0);
261 OUT32(id, I2CMCR, MCR_MIE | MCR_ESG);
262 OUT32(id, I2CMIER, MIE_MNRE | MIE_MALE | MIE_MSTE | MIE_MATE);
263 OUT32(id, I2CFIER, FIER_RXIE);
264 }
265
266 /* prepare and start a master send operation */
267 static void sh7760_i2c_msend(struct cami2c *id)
268 {
269 int len;
270
271 id->flags |= IDF_SEND;
272
273 /* set the slave addr reg; otherwise xmit wont work! */
274 OUT32(id, I2CSAR, 0xfe);
275 OUT32(id, I2CMAR, (id->msg->addr << 1) | 0);
276
277 /* adjust tx fifo trigger */
278 if (id->msg->len >= FIFO_SIZE)
279 len = 2; /* trig: 2 bytes left in TX fifo */
280 else
281 len = 0; /* trig: 8 bytes left in TX fifo */
282
283 OUT32(id, I2CFCR, FCR_RFRST | FCR_TFRST);
284 OUT32(id, I2CFCR, FCR_RFRST | ((len & 3) << 2));
285
286 while (id->msg->len && IN32(id, I2CTFDR) < FIFO_SIZE) {
287 OUT32(id, I2CRXTX, *(id->msg->buf));
288 (id->msg->len)--;
289 (id->msg->buf)++;
290 }
291
292 OUT32(id, I2CMSR, 0);
293 OUT32(id, I2CMCR, MCR_MIE | MCR_ESG);
294 OUT32(id, I2CFSR, 0);
295 OUT32(id, I2CMIER, MIE_MNRE | MIE_MALE | MIE_MSTE | MIE_MATE);
296 OUT32(id, I2CFIER, FIER_TEIE | (id->msg->len ? FIER_TXIE : 0));
297 }
298
299 static inline int sh7760_i2c_busy_check(struct cami2c *id)
300 {
301 return (IN32(id, I2CMCR) & MCR_FSDA);
302 }
303
304 static int sh7760_i2c_master_xfer(struct i2c_adapter *adap,
305 struct i2c_msg *msgs,
306 int num)
307 {
308 struct cami2c *id = adap->algo_data;
309 int i, retr;
310
311 if (sh7760_i2c_busy_check(id)) {
312 dev_err(&adap->dev, "sh7760-i2c%d: bus busy!\n", adap->nr);
313 return -EBUSY;
314 }
315
316 i = 0;
317 while (i < num) {
318 retr = adap->retries;
319 retry:
320 id->flags = ((i == (num-1)) ? IDF_STOP : 0);
321 id->status = 0;
322 id->msg = msgs;
323 init_completion(&id->xfer_done);
324
325 if (msgs->flags & I2C_M_RD)
326 sh7760_i2c_mrecv(id);
327 else
328 sh7760_i2c_msend(id);
329
330 wait_for_completion(&id->xfer_done);
331
332 if (id->status == 0) {
333 num = -EIO;
334 break;
335 }
336
337 if (id->status & IDS_NACK) {
338 /* wait a bit or i2c module stops working */
339 mdelay(1);
340 num = -EREMOTEIO;
341 break;
342 }
343
344 if (id->status & IDS_ARBLOST) {
345 if (retr--) {
346 mdelay(2);
347 goto retry;
348 }
349 num = -EREMOTEIO;
350 break;
351 }
352
353 msgs++;
354 i++;
355 }
356
357 id->msg = NULL;
358 id->flags = 0;
359 id->status = 0;
360
361 OUT32(id, I2CMCR, 0);
362 OUT32(id, I2CMSR, 0);
363 OUT32(id, I2CMIER, 0);
364 OUT32(id, I2CFIER, 0);
365
366 /* reset slave module registers too: master mode enables slave
367 * module for receive ops (ack, data). Without this reset,
368 * eternal bus activity might be reported after NACK / ARBLOST.
369 */
370 OUT32(id, I2CSCR, 0);
371 OUT32(id, I2CSAR, 0);
372 OUT32(id, I2CSSR, 0);
373
374 return num;
375 }
376
377 static u32 sh7760_i2c_func(struct i2c_adapter *adap)
378 {
379 return I2C_FUNC_I2C | (I2C_FUNC_SMBUS_EMUL & ~I2C_FUNC_SMBUS_QUICK);
380 }
381
382 static const struct i2c_algorithm sh7760_i2c_algo = {
383 .master_xfer = sh7760_i2c_master_xfer,
384 .functionality = sh7760_i2c_func,
385 };
386
387 /* calculate CCR register setting for a desired scl clock. SCL clock is
388 * derived from I2C module clock (iclk) which in turn is derived from
389 * peripheral module clock (mclk, usually around 33MHz):
390 * iclk = mclk/(CDF + 1). iclk must be < 20MHz.
391 * scl = iclk/(SCGD*8 + 20).
392 */
393 static int __devinit calc_CCR(unsigned long scl_hz)
394 {
395 struct clk *mclk;
396 unsigned long mck, m1, dff, odff, iclk;
397 signed char cdf, cdfm;
398 int scgd, scgdm, scgds;
399
400 mclk = clk_get(NULL, "peripheral_clk");
401 if (IS_ERR(mclk)) {
402 return PTR_ERR(mclk);
403 } else {
404 mck = mclk->rate;
405 clk_put(mclk);
406 }
407
408 odff = scl_hz;
409 scgdm = cdfm = m1 = 0;
410 for (cdf = 3; cdf >= 0; cdf--) {
411 iclk = mck / (1 + cdf);
412 if (iclk >= 20000000)
413 continue;
414 scgds = ((iclk / scl_hz) - 20) >> 3;
415 for (scgd = scgds; (scgd < 63) && scgd <= scgds + 1; scgd++) {
416 m1 = iclk / (20 + (scgd << 3));
417 dff = abs(scl_hz - m1);
418 if (dff < odff) {
419 odff = dff;
420 cdfm = cdf;
421 scgdm = scgd;
422 }
423 }
424 }
425 /* fail if more than 25% off of requested SCL */
426 if (odff > (scl_hz >> 2))
427 return -EINVAL;
428
429 /* create a CCR register value */
430 return ((scgdm << 2) | cdfm);
431 }
432
433 static int __devinit sh7760_i2c_probe(struct platform_device *pdev)
434 {
435 struct sh7760_i2c_platdata *pd;
436 struct resource *res;
437 struct cami2c *id;
438 int ret;
439
440 pd = pdev->dev.platform_data;
441 if (!pd) {
442 dev_err(&pdev->dev, "no platform_data!\n");
443 ret = -ENODEV;
444 goto out0;
445 }
446
447 id = kzalloc(sizeof(struct cami2c), GFP_KERNEL);
448 if (!id) {
449 dev_err(&pdev->dev, "no mem for private data\n");
450 ret = -ENOMEM;
451 goto out0;
452 }
453
454 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
455 if (!res) {
456 dev_err(&pdev->dev, "no mmio resources\n");
457 ret = -ENODEV;
458 goto out1;
459 }
460
461 id->ioarea = request_mem_region(res->start, REGSIZE, pdev->name);
462 if (!id->ioarea) {
463 dev_err(&pdev->dev, "mmio already reserved\n");
464 ret = -EBUSY;
465 goto out1;
466 }
467
468 id->iobase = ioremap(res->start, REGSIZE);
469 if (!id->iobase) {
470 dev_err(&pdev->dev, "cannot ioremap\n");
471 ret = -ENODEV;
472 goto out2;
473 }
474
475 id->irq = platform_get_irq(pdev, 0);
476
477 id->adap.nr = pdev->id;
478 id->adap.algo = &sh7760_i2c_algo;
479 id->adap.class = I2C_CLASS_HWMON | I2C_CLASS_SPD;
480 id->adap.retries = 3;
481 id->adap.algo_data = id;
482 id->adap.dev.parent = &pdev->dev;
483 snprintf(id->adap.name, sizeof(id->adap.name),
484 "SH7760 I2C at %08lx", (unsigned long)res->start);
485
486 OUT32(id, I2CMCR, 0);
487 OUT32(id, I2CMSR, 0);
488 OUT32(id, I2CMIER, 0);
489 OUT32(id, I2CMAR, 0);
490 OUT32(id, I2CSIER, 0);
491 OUT32(id, I2CSAR, 0);
492 OUT32(id, I2CSCR, 0);
493 OUT32(id, I2CSSR, 0);
494 OUT32(id, I2CFIER, 0);
495 OUT32(id, I2CFCR, FCR_RFRST | FCR_TFRST);
496 OUT32(id, I2CFSR, 0);
497
498 ret = calc_CCR(pd->speed_khz * 1000);
499 if (ret < 0) {
500 dev_err(&pdev->dev, "invalid SCL clock: %dkHz\n",
501 pd->speed_khz);
502 goto out3;
503 }
504 OUT32(id, I2CCCR, ret);
505
506 if (request_irq(id->irq, sh7760_i2c_irq, 0,
507 SH7760_I2C_DEVNAME, id)) {
508 dev_err(&pdev->dev, "cannot get irq %d\n", id->irq);
509 ret = -EBUSY;
510 goto out3;
511 }
512
513 ret = i2c_add_numbered_adapter(&id->adap);
514 if (ret < 0) {
515 dev_err(&pdev->dev, "reg adap failed: %d\n", ret);
516 goto out4;
517 }
518
519 platform_set_drvdata(pdev, id);
520
521 dev_info(&pdev->dev, "%d kHz mmio %08x irq %d\n",
522 pd->speed_khz, res->start, id->irq);
523
524 return 0;
525
526 out4:
527 free_irq(id->irq, id);
528 out3:
529 iounmap(id->iobase);
530 out2:
531 release_resource(id->ioarea);
532 kfree(id->ioarea);
533 out1:
534 kfree(id);
535 out0:
536 return ret;
537 }
538
539 static int __devexit sh7760_i2c_remove(struct platform_device *pdev)
540 {
541 struct cami2c *id = platform_get_drvdata(pdev);
542
543 i2c_del_adapter(&id->adap);
544 free_irq(id->irq, id);
545 iounmap(id->iobase);
546 release_resource(id->ioarea);
547 kfree(id->ioarea);
548 kfree(id);
549 platform_set_drvdata(pdev, NULL);
550
551 return 0;
552 }
553
554 static struct platform_driver sh7760_i2c_drv = {
555 .driver = {
556 .name = SH7760_I2C_DEVNAME,
557 .owner = THIS_MODULE,
558 },
559 .probe = sh7760_i2c_probe,
560 .remove = __devexit_p(sh7760_i2c_remove),
561 };
562
563 module_platform_driver(sh7760_i2c_drv);
564
565 MODULE_LICENSE("GPL");
566 MODULE_DESCRIPTION("SH7760 I2C bus driver");
567 MODULE_AUTHOR("Manuel Lauss <mano@roarinelk.homelinux.net>");
Linux with added FPC-III support