Merge master.kernel.org:/pub/scm/linux/kernel/git/lethal/genesis-2.6 into devel-stable
[pandora-kernel.git] / drivers / i2c / busses / i2c-octeon.c
1 /*
2  * (C) Copyright 2009-2010
3  * Nokia Siemens Networks, michael.lawnick.ext@nsn.com
4  *
5  * Portions Copyright (C) 2010 Cavium Networks, Inc.
6  *
7  * This is a driver for the i2c adapter in Cavium Networks' OCTEON processors.
8  *
9  * This file is licensed under the terms of the GNU General Public
10  * License version 2. This program is licensed "as is" without any
11  * warranty of any kind, whether express or implied.
12  */
13
14 #include <linux/kernel.h>
15 #include <linux/module.h>
16 #include <linux/sched.h>
17 #include <linux/slab.h>
18 #include <linux/init.h>
19
20 #include <linux/io.h>
21 #include <linux/i2c.h>
22 #include <linux/interrupt.h>
23 #include <linux/delay.h>
24 #include <linux/platform_device.h>
25
26 #include <asm/octeon/octeon.h>
27
28 #define DRV_NAME "i2c-octeon"
29
30 /* The previous out-of-tree version was implicitly version 1.0. */
31 #define DRV_VERSION     "2.0"
32
33 /* register offsets */
34 #define SW_TWSI  0x00
35 #define TWSI_INT 0x10
36
37 /* Controller command patterns */
38 #define SW_TWSI_V               0x8000000000000000ull
39 #define SW_TWSI_EOP_TWSI_DATA   0x0C00000100000000ull
40 #define SW_TWSI_EOP_TWSI_CTL    0x0C00000200000000ull
41 #define SW_TWSI_EOP_TWSI_CLKCTL 0x0C00000300000000ull
42 #define SW_TWSI_EOP_TWSI_STAT   0x0C00000300000000ull
43 #define SW_TWSI_EOP_TWSI_RST    0x0C00000700000000ull
44 #define SW_TWSI_OP_TWSI_CLK     0x0800000000000000ull
45 #define SW_TWSI_R               0x0100000000000000ull
46
47 /* Controller command and status bits */
48 #define TWSI_CTL_CE   0x80
49 #define TWSI_CTL_ENAB 0x40
50 #define TWSI_CTL_STA  0x20
51 #define TWSI_CTL_STP  0x10
52 #define TWSI_CTL_IFLG 0x08
53 #define TWSI_CTL_AAK  0x04
54
55 /* Some status values */
56 #define STAT_START      0x08
57 #define STAT_RSTART     0x10
58 #define STAT_TXADDR_ACK 0x18
59 #define STAT_TXDATA_ACK 0x28
60 #define STAT_RXADDR_ACK 0x40
61 #define STAT_RXDATA_ACK 0x50
62 #define STAT_IDLE       0xF8
63
64 struct octeon_i2c {
65         wait_queue_head_t queue;
66         struct i2c_adapter adap;
67         int irq;
68         int twsi_freq;
69         int sys_freq;
70         resource_size_t twsi_phys;
71         void __iomem *twsi_base;
72         resource_size_t regsize;
73         struct device *dev;
74 };
75
76 /**
77  * octeon_i2c_write_sw - write an I2C core register.
78  * @i2c: The struct octeon_i2c.
79  * @eop_reg: Register selector.
80  * @data: Value to be written.
81  *
82  * The I2C core registers are accessed indirectly via the SW_TWSI CSR.
83  */
84 static void octeon_i2c_write_sw(struct octeon_i2c *i2c,
85                                 u64 eop_reg,
86                                 u8 data)
87 {
88         u64 tmp;
89
90         __raw_writeq(SW_TWSI_V | eop_reg | data, i2c->twsi_base + SW_TWSI);
91         do {
92                 tmp = __raw_readq(i2c->twsi_base + SW_TWSI);
93         } while ((tmp & SW_TWSI_V) != 0);
94 }
95
96 /**
97  * octeon_i2c_read_sw - write an I2C core register.
98  * @i2c: The struct octeon_i2c.
99  * @eop_reg: Register selector.
100  *
101  * Returns the data.
102  *
103  * The I2C core registers are accessed indirectly via the SW_TWSI CSR.
104  */
105 static u8 octeon_i2c_read_sw(struct octeon_i2c *i2c, u64 eop_reg)
106 {
107         u64 tmp;
108
109         __raw_writeq(SW_TWSI_V | eop_reg | SW_TWSI_R, i2c->twsi_base + SW_TWSI);
110         do {
111                 tmp = __raw_readq(i2c->twsi_base + SW_TWSI);
112         } while ((tmp & SW_TWSI_V) != 0);
113
114         return tmp & 0xFF;
115 }
116
117 /**
118  * octeon_i2c_write_int - write the TWSI_INT register
119  * @i2c: The struct octeon_i2c.
120  * @data: Value to be written.
121  */
122 static void octeon_i2c_write_int(struct octeon_i2c *i2c, u64 data)
123 {
124         u64 tmp;
125
126         __raw_writeq(data, i2c->twsi_base + TWSI_INT);
127         tmp = __raw_readq(i2c->twsi_base + TWSI_INT);
128 }
129
130 /**
131  * octeon_i2c_int_enable - enable the TS interrupt.
132  * @i2c: The struct octeon_i2c.
133  *
134  * The interrupt will be asserted when there is non-STAT_IDLE state in
135  * the SW_TWSI_EOP_TWSI_STAT register.
136  */
137 static void octeon_i2c_int_enable(struct octeon_i2c *i2c)
138 {
139         octeon_i2c_write_int(i2c, 0x40);
140 }
141
142 /**
143  * octeon_i2c_int_disable - disable the TS interrupt.
144  * @i2c: The struct octeon_i2c.
145  */
146 static void octeon_i2c_int_disable(struct octeon_i2c *i2c)
147 {
148         octeon_i2c_write_int(i2c, 0);
149 }
150
151 /**
152  * octeon_i2c_unblock - unblock the bus.
153  * @i2c: The struct octeon_i2c.
154  *
155  * If there was a reset while a device was driving 0 to bus,
156  * bus is blocked. We toggle it free manually by some clock
157  * cycles and send a stop.
158  */
159 static void octeon_i2c_unblock(struct octeon_i2c *i2c)
160 {
161         int i;
162
163         dev_dbg(i2c->dev, "%s\n", __func__);
164         for (i = 0; i < 9; i++) {
165                 octeon_i2c_write_int(i2c, 0x0);
166                 udelay(5);
167                 octeon_i2c_write_int(i2c, 0x200);
168                 udelay(5);
169         }
170         octeon_i2c_write_int(i2c, 0x300);
171         udelay(5);
172         octeon_i2c_write_int(i2c, 0x100);
173         udelay(5);
174         octeon_i2c_write_int(i2c, 0x0);
175 }
176
177 /**
178  * octeon_i2c_isr - the interrupt service routine.
179  * @int: The irq, unused.
180  * @dev_id: Our struct octeon_i2c.
181  */
182 static irqreturn_t octeon_i2c_isr(int irq, void *dev_id)
183 {
184         struct octeon_i2c *i2c = dev_id;
185
186         octeon_i2c_int_disable(i2c);
187         wake_up_interruptible(&i2c->queue);
188
189         return IRQ_HANDLED;
190 }
191
192
193 static int octeon_i2c_test_iflg(struct octeon_i2c *i2c)
194 {
195         return (octeon_i2c_read_sw(i2c, SW_TWSI_EOP_TWSI_CTL) & TWSI_CTL_IFLG) != 0;
196 }
197
198 /**
199  * octeon_i2c_wait - wait for the IFLG to be set.
200  * @i2c: The struct octeon_i2c.
201  *
202  * Returns 0 on success, otherwise a negative errno.
203  */
204 static int octeon_i2c_wait(struct octeon_i2c *i2c)
205 {
206         int result;
207
208         octeon_i2c_int_enable(i2c);
209
210         result = wait_event_interruptible_timeout(i2c->queue,
211                                                   octeon_i2c_test_iflg(i2c),
212                                                   i2c->adap.timeout);
213
214         octeon_i2c_int_disable(i2c);
215
216         if (result < 0) {
217                 dev_dbg(i2c->dev, "%s: wait interrupted\n", __func__);
218                 return result;
219         } else if (result == 0) {
220                 dev_dbg(i2c->dev, "%s: timeout\n", __func__);
221                 return -ETIMEDOUT;
222         }
223
224         return 0;
225 }
226
227 /**
228  * octeon_i2c_start - send START to the bus.
229  * @i2c: The struct octeon_i2c.
230  *
231  * Returns 0 on success, otherwise a negative errno.
232  */
233 static int octeon_i2c_start(struct octeon_i2c *i2c)
234 {
235         u8 data;
236         int result;
237
238         octeon_i2c_write_sw(i2c, SW_TWSI_EOP_TWSI_CTL,
239                                 TWSI_CTL_ENAB | TWSI_CTL_STA);
240
241         result = octeon_i2c_wait(i2c);
242         if (result) {
243                 if (octeon_i2c_read_sw(i2c, SW_TWSI_EOP_TWSI_STAT) == STAT_IDLE) {
244                         /*
245                          * Controller refused to send start flag May
246                          * be a client is holding SDA low - let's try
247                          * to free it.
248                          */
249                         octeon_i2c_unblock(i2c);
250                         octeon_i2c_write_sw(i2c, SW_TWSI_EOP_TWSI_CTL,
251                                             TWSI_CTL_ENAB | TWSI_CTL_STA);
252
253                         result = octeon_i2c_wait(i2c);
254                 }
255                 if (result)
256                         return result;
257         }
258
259         data = octeon_i2c_read_sw(i2c, SW_TWSI_EOP_TWSI_STAT);
260         if ((data != STAT_START) && (data != STAT_RSTART)) {
261                 dev_err(i2c->dev, "%s: bad status (0x%x)\n", __func__, data);
262                 return -EIO;
263         }
264
265         return 0;
266 }
267
268 /**
269  * octeon_i2c_stop - send STOP to the bus.
270  * @i2c: The struct octeon_i2c.
271  *
272  * Returns 0 on success, otherwise a negative errno.
273  */
274 static int octeon_i2c_stop(struct octeon_i2c *i2c)
275 {
276         u8 data;
277
278         octeon_i2c_write_sw(i2c, SW_TWSI_EOP_TWSI_CTL,
279                             TWSI_CTL_ENAB | TWSI_CTL_STP);
280
281         data = octeon_i2c_read_sw(i2c, SW_TWSI_EOP_TWSI_STAT);
282
283         if (data != STAT_IDLE) {
284                 dev_err(i2c->dev, "%s: bad status(0x%x)\n", __func__, data);
285                 return -EIO;
286         }
287         return 0;
288 }
289
290 /**
291  * octeon_i2c_write - send data to the bus.
292  * @i2c: The struct octeon_i2c.
293  * @target: Target address.
294  * @data: Pointer to the data to be sent.
295  * @length: Length of the data.
296  *
297  * The address is sent over the bus, then the data.
298  *
299  * Returns 0 on success, otherwise a negative errno.
300  */
301 static int octeon_i2c_write(struct octeon_i2c *i2c, int target,
302                             const u8 *data, int length)
303 {
304         int i, result;
305         u8 tmp;
306
307         result = octeon_i2c_start(i2c);
308         if (result)
309                 return result;
310
311         octeon_i2c_write_sw(i2c, SW_TWSI_EOP_TWSI_DATA, target << 1);
312         octeon_i2c_write_sw(i2c, SW_TWSI_EOP_TWSI_CTL, TWSI_CTL_ENAB);
313
314         result = octeon_i2c_wait(i2c);
315         if (result)
316                 return result;
317
318         for (i = 0; i < length; i++) {
319                 tmp = octeon_i2c_read_sw(i2c, SW_TWSI_EOP_TWSI_STAT);
320                 if ((tmp != STAT_TXADDR_ACK) && (tmp != STAT_TXDATA_ACK)) {
321                         dev_err(i2c->dev,
322                                 "%s: bad status before write (0x%x)\n",
323                                 __func__, tmp);
324                         return -EIO;
325                 }
326
327                 octeon_i2c_write_sw(i2c, SW_TWSI_EOP_TWSI_DATA, data[i]);
328                 octeon_i2c_write_sw(i2c, SW_TWSI_EOP_TWSI_CTL, TWSI_CTL_ENAB);
329
330                 result = octeon_i2c_wait(i2c);
331                 if (result)
332                         return result;
333         }
334
335         return 0;
336 }
337
338 /**
339  * octeon_i2c_read - receive data from the bus.
340  * @i2c: The struct octeon_i2c.
341  * @target: Target address.
342  * @data: Pointer to the location to store the datae .
343  * @length: Length of the data.
344  *
345  * The address is sent over the bus, then the data is read.
346  *
347  * Returns 0 on success, otherwise a negative errno.
348  */
349 static int octeon_i2c_read(struct octeon_i2c *i2c, int target,
350                            u8 *data, int length)
351 {
352         int i, result;
353         u8 tmp;
354
355         if (length < 1)
356                 return -EINVAL;
357
358         result = octeon_i2c_start(i2c);
359         if (result)
360                 return result;
361
362         octeon_i2c_write_sw(i2c, SW_TWSI_EOP_TWSI_DATA, (target<<1) | 1);
363         octeon_i2c_write_sw(i2c, SW_TWSI_EOP_TWSI_CTL, TWSI_CTL_ENAB);
364
365         result = octeon_i2c_wait(i2c);
366         if (result)
367                 return result;
368
369         for (i = 0; i < length; i++) {
370                 tmp = octeon_i2c_read_sw(i2c, SW_TWSI_EOP_TWSI_STAT);
371                 if ((tmp != STAT_RXDATA_ACK) && (tmp != STAT_RXADDR_ACK)) {
372                         dev_err(i2c->dev,
373                                 "%s: bad status before read (0x%x)\n",
374                                 __func__, tmp);
375                         return -EIO;
376                 }
377
378                 if (i+1 < length)
379                         octeon_i2c_write_sw(i2c, SW_TWSI_EOP_TWSI_CTL,
380                                                 TWSI_CTL_ENAB | TWSI_CTL_AAK);
381                 else
382                         octeon_i2c_write_sw(i2c, SW_TWSI_EOP_TWSI_CTL,
383                                                 TWSI_CTL_ENAB);
384
385                 result = octeon_i2c_wait(i2c);
386                 if (result)
387                         return result;
388
389                 data[i] = octeon_i2c_read_sw(i2c, SW_TWSI_EOP_TWSI_DATA);
390         }
391         return 0;
392 }
393
394 /**
395  * octeon_i2c_xfer - The driver's master_xfer function.
396  * @adap: Pointer to the i2c_adapter structure.
397  * @msgs: Pointer to the messages to be processed.
398  * @num: Length of the MSGS array.
399  *
400  * Returns the number of messages processed, or a negative errno on
401  * failure.
402  */
403 static int octeon_i2c_xfer(struct i2c_adapter *adap,
404                            struct i2c_msg *msgs,
405                            int num)
406 {
407         struct i2c_msg *pmsg;
408         int i;
409         int ret = 0;
410         struct octeon_i2c *i2c = i2c_get_adapdata(adap);
411
412         for (i = 0; ret == 0 && i < num; i++) {
413                 pmsg = &msgs[i];
414                 dev_dbg(i2c->dev,
415                         "Doing %s %d byte(s) to/from 0x%02x - %d of %d messages\n",
416                          pmsg->flags & I2C_M_RD ? "read" : "write",
417                          pmsg->len, pmsg->addr, i + 1, num);
418                 if (pmsg->flags & I2C_M_RD)
419                         ret = octeon_i2c_read(i2c, pmsg->addr, pmsg->buf,
420                                                 pmsg->len);
421                 else
422                         ret = octeon_i2c_write(i2c, pmsg->addr, pmsg->buf,
423                                                 pmsg->len);
424         }
425         octeon_i2c_stop(i2c);
426
427         return (ret != 0) ? ret : num;
428 }
429
430 static u32 octeon_i2c_functionality(struct i2c_adapter *adap)
431 {
432         return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
433 }
434
435 static const struct i2c_algorithm octeon_i2c_algo = {
436         .master_xfer = octeon_i2c_xfer,
437         .functionality = octeon_i2c_functionality,
438 };
439
440 static struct i2c_adapter octeon_i2c_ops = {
441         .owner = THIS_MODULE,
442         .name = "OCTEON adapter",
443         .algo = &octeon_i2c_algo,
444         .timeout = 2,
445 };
446
447 /**
448  * octeon_i2c_setclock - Calculate and set clock divisors.
449  */
450 static int __devinit octeon_i2c_setclock(struct octeon_i2c *i2c)
451 {
452         int tclk, thp_base, inc, thp_idx, mdiv_idx, ndiv_idx, foscl, diff;
453         int thp = 0x18, mdiv = 2, ndiv = 0, delta_hz = 1000000;
454
455         for (ndiv_idx = 0; ndiv_idx < 8 && delta_hz != 0; ndiv_idx++) {
456                 /*
457                  * An mdiv value of less than 2 seems to not work well
458                  * with ds1337 RTCs, so we constrain it to larger
459                  * values.
460                  */
461                 for (mdiv_idx = 15; mdiv_idx >= 2 && delta_hz != 0; mdiv_idx--) {
462                         /*
463                          * For given ndiv and mdiv values check the
464                          * two closest thp values.
465                          */
466                         tclk = i2c->twsi_freq * (mdiv_idx + 1) * 10;
467                         tclk *= (1 << ndiv_idx);
468                         thp_base = (i2c->sys_freq / (tclk * 2)) - 1;
469                         for (inc = 0; inc <= 1; inc++) {
470                                 thp_idx = thp_base + inc;
471                                 if (thp_idx < 5 || thp_idx > 0xff)
472                                         continue;
473
474                                 foscl = i2c->sys_freq / (2 * (thp_idx + 1));
475                                 foscl = foscl / (1 << ndiv_idx);
476                                 foscl = foscl / (mdiv_idx + 1) / 10;
477                                 diff = abs(foscl - i2c->twsi_freq);
478                                 if (diff < delta_hz) {
479                                         delta_hz = diff;
480                                         thp = thp_idx;
481                                         mdiv = mdiv_idx;
482                                         ndiv = ndiv_idx;
483                                 }
484                         }
485                 }
486         }
487         octeon_i2c_write_sw(i2c, SW_TWSI_OP_TWSI_CLK, thp);
488         octeon_i2c_write_sw(i2c, SW_TWSI_EOP_TWSI_CLKCTL, (mdiv << 3) | ndiv);
489
490         return 0;
491 }
492
493 static int __devinit octeon_i2c_initlowlevel(struct octeon_i2c *i2c)
494 {
495         u8 status;
496         int tries;
497
498         /* disable high level controller, enable bus access */
499         octeon_i2c_write_sw(i2c, SW_TWSI_EOP_TWSI_CTL, TWSI_CTL_ENAB);
500
501         /* reset controller */
502         octeon_i2c_write_sw(i2c, SW_TWSI_EOP_TWSI_RST, 0);
503
504         for (tries = 10; tries; tries--) {
505                 udelay(1);
506                 status = octeon_i2c_read_sw(i2c, SW_TWSI_EOP_TWSI_STAT);
507                 if (status == STAT_IDLE)
508                         return 0;
509         }
510         dev_err(i2c->dev, "%s: TWSI_RST failed! (0x%x)\n", __func__, status);
511         return -EIO;
512 }
513
514 static int __devinit octeon_i2c_probe(struct platform_device *pdev)
515 {
516         int irq, result = 0;
517         struct octeon_i2c *i2c;
518         struct octeon_i2c_data *i2c_data;
519         struct resource *res_mem;
520
521         /* All adaptors have an irq.  */
522         irq = platform_get_irq(pdev, 0);
523         if (irq < 0)
524                 return irq;
525
526         i2c = kzalloc(sizeof(*i2c), GFP_KERNEL);
527         if (!i2c) {
528                 dev_err(&pdev->dev, "kzalloc failed\n");
529                 result = -ENOMEM;
530                 goto out;
531         }
532         i2c->dev = &pdev->dev;
533         i2c_data = pdev->dev.platform_data;
534
535         res_mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
536
537         if (res_mem == NULL) {
538                 dev_err(i2c->dev, "found no memory resource\n");
539                 result = -ENXIO;
540                 goto fail_region;
541         }
542
543         if (i2c_data == NULL) {
544                 dev_err(i2c->dev, "no I2C frequency data\n");
545                 result = -ENXIO;
546                 goto fail_region;
547         }
548
549         i2c->twsi_phys = res_mem->start;
550         i2c->regsize = resource_size(res_mem);
551         i2c->twsi_freq = i2c_data->i2c_freq;
552         i2c->sys_freq = i2c_data->sys_freq;
553
554         if (!request_mem_region(i2c->twsi_phys, i2c->regsize, res_mem->name)) {
555                 dev_err(i2c->dev, "request_mem_region failed\n");
556                 goto fail_region;
557         }
558         i2c->twsi_base = ioremap(i2c->twsi_phys, i2c->regsize);
559
560         init_waitqueue_head(&i2c->queue);
561
562         i2c->irq = irq;
563
564         result = request_irq(i2c->irq, octeon_i2c_isr, 0, DRV_NAME, i2c);
565         if (result < 0) {
566                 dev_err(i2c->dev, "failed to attach interrupt\n");
567                 goto fail_irq;
568         }
569
570         result = octeon_i2c_initlowlevel(i2c);
571         if (result) {
572                 dev_err(i2c->dev, "init low level failed\n");
573                 goto  fail_add;
574         }
575
576         result = octeon_i2c_setclock(i2c);
577         if (result) {
578                 dev_err(i2c->dev, "clock init failed\n");
579                 goto  fail_add;
580         }
581
582         i2c->adap = octeon_i2c_ops;
583         i2c->adap.dev.parent = &pdev->dev;
584         i2c->adap.nr = pdev->id >= 0 ? pdev->id : 0;
585         i2c_set_adapdata(&i2c->adap, i2c);
586         platform_set_drvdata(pdev, i2c);
587
588         result = i2c_add_numbered_adapter(&i2c->adap);
589         if (result < 0) {
590                 dev_err(i2c->dev, "failed to add adapter\n");
591                 goto fail_add;
592         }
593
594         dev_info(i2c->dev, "version %s\n", DRV_VERSION);
595
596         return result;
597
598 fail_add:
599         platform_set_drvdata(pdev, NULL);
600         free_irq(i2c->irq, i2c);
601 fail_irq:
602         iounmap(i2c->twsi_base);
603         release_mem_region(i2c->twsi_phys, i2c->regsize);
604 fail_region:
605         kfree(i2c);
606 out:
607         return result;
608 };
609
610 static int __devexit octeon_i2c_remove(struct platform_device *pdev)
611 {
612         struct octeon_i2c *i2c = platform_get_drvdata(pdev);
613
614         i2c_del_adapter(&i2c->adap);
615         platform_set_drvdata(pdev, NULL);
616         free_irq(i2c->irq, i2c);
617         iounmap(i2c->twsi_base);
618         release_mem_region(i2c->twsi_phys, i2c->regsize);
619         kfree(i2c);
620         return 0;
621 };
622
623 static struct platform_driver octeon_i2c_driver = {
624         .probe          = octeon_i2c_probe,
625         .remove         = __devexit_p(octeon_i2c_remove),
626         .driver         = {
627                 .owner  = THIS_MODULE,
628                 .name   = DRV_NAME,
629         },
630 };
631
632 static int __init octeon_i2c_init(void)
633 {
634         int rv;
635
636         rv = platform_driver_register(&octeon_i2c_driver);
637         return rv;
638 }
639
640 static void __exit octeon_i2c_exit(void)
641 {
642         platform_driver_unregister(&octeon_i2c_driver);
643 }
644
645 MODULE_AUTHOR("Michael Lawnick <michael.lawnick.ext@nsn.com>");
646 MODULE_DESCRIPTION("I2C-Bus adapter for Cavium OCTEON processors");
647 MODULE_LICENSE("GPL");
648 MODULE_VERSION(DRV_VERSION);
649 MODULE_ALIAS("platform:" DRV_NAME);
650
651 module_init(octeon_i2c_init);
652 module_exit(octeon_i2c_exit);