Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/linville/wirel...
[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, 2011 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/platform_device.h>
15 #include <linux/interrupt.h>
16 #include <linux/kernel.h>
17 #include <linux/module.h>
18 #include <linux/of_i2c.h>
19 #include <linux/delay.h>
20 #include <linux/sched.h>
21 #include <linux/slab.h>
22 #include <linux/init.h>
23 #include <linux/i2c.h>
24 #include <linux/io.h>
25 #include <linux/of.h>
26
27 #include <asm/octeon/octeon.h>
28
29 #define DRV_NAME "i2c-octeon"
30
31 /* The previous out-of-tree version was implicitly version 1.0. */
32 #define DRV_VERSION     "2.0"
33
34 /* register offsets */
35 #define SW_TWSI  0x00
36 #define TWSI_INT 0x10
37
38 /* Controller command patterns */
39 #define SW_TWSI_V               0x8000000000000000ull
40 #define SW_TWSI_EOP_TWSI_DATA   0x0C00000100000000ull
41 #define SW_TWSI_EOP_TWSI_CTL    0x0C00000200000000ull
42 #define SW_TWSI_EOP_TWSI_CLKCTL 0x0C00000300000000ull
43 #define SW_TWSI_EOP_TWSI_STAT   0x0C00000300000000ull
44 #define SW_TWSI_EOP_TWSI_RST    0x0C00000700000000ull
45 #define SW_TWSI_OP_TWSI_CLK     0x0800000000000000ull
46 #define SW_TWSI_R               0x0100000000000000ull
47
48 /* Controller command and status bits */
49 #define TWSI_CTL_CE   0x80
50 #define TWSI_CTL_ENAB 0x40
51 #define TWSI_CTL_STA  0x20
52 #define TWSI_CTL_STP  0x10
53 #define TWSI_CTL_IFLG 0x08
54 #define TWSI_CTL_AAK  0x04
55
56 /* Some status values */
57 #define STAT_START      0x08
58 #define STAT_RSTART     0x10
59 #define STAT_TXADDR_ACK 0x18
60 #define STAT_TXDATA_ACK 0x28
61 #define STAT_RXADDR_ACK 0x40
62 #define STAT_RXDATA_ACK 0x50
63 #define STAT_IDLE       0xF8
64
65 struct octeon_i2c {
66         wait_queue_head_t queue;
67         struct i2c_adapter adap;
68         int irq;
69         u32 twsi_freq;
70         int sys_freq;
71         resource_size_t twsi_phys;
72         void __iomem *twsi_base;
73         resource_size_t regsize;
74         struct device *dev;
75 };
76
77 /**
78  * octeon_i2c_write_sw - write an I2C core register.
79  * @i2c: The struct octeon_i2c.
80  * @eop_reg: Register selector.
81  * @data: Value to be written.
82  *
83  * The I2C core registers are accessed indirectly via the SW_TWSI CSR.
84  */
85 static void octeon_i2c_write_sw(struct octeon_i2c *i2c,
86                                 u64 eop_reg,
87                                 u8 data)
88 {
89         u64 tmp;
90
91         __raw_writeq(SW_TWSI_V | eop_reg | data, i2c->twsi_base + SW_TWSI);
92         do {
93                 tmp = __raw_readq(i2c->twsi_base + SW_TWSI);
94         } while ((tmp & SW_TWSI_V) != 0);
95 }
96
97 /**
98  * octeon_i2c_read_sw - write an I2C core register.
99  * @i2c: The struct octeon_i2c.
100  * @eop_reg: Register selector.
101  *
102  * Returns the data.
103  *
104  * The I2C core registers are accessed indirectly via the SW_TWSI CSR.
105  */
106 static u8 octeon_i2c_read_sw(struct octeon_i2c *i2c, u64 eop_reg)
107 {
108         u64 tmp;
109
110         __raw_writeq(SW_TWSI_V | eop_reg | SW_TWSI_R, i2c->twsi_base + SW_TWSI);
111         do {
112                 tmp = __raw_readq(i2c->twsi_base + SW_TWSI);
113         } while ((tmp & SW_TWSI_V) != 0);
114
115         return tmp & 0xFF;
116 }
117
118 /**
119  * octeon_i2c_write_int - write the TWSI_INT register
120  * @i2c: The struct octeon_i2c.
121  * @data: Value to be written.
122  */
123 static void octeon_i2c_write_int(struct octeon_i2c *i2c, u64 data)
124 {
125         __raw_writeq(data, i2c->twsi_base + TWSI_INT);
126         __raw_readq(i2c->twsi_base + TWSI_INT);
127 }
128
129 /**
130  * octeon_i2c_int_enable - enable the TS interrupt.
131  * @i2c: The struct octeon_i2c.
132  *
133  * The interrupt will be asserted when there is non-STAT_IDLE state in
134  * the SW_TWSI_EOP_TWSI_STAT register.
135  */
136 static void octeon_i2c_int_enable(struct octeon_i2c *i2c)
137 {
138         octeon_i2c_write_int(i2c, 0x40);
139 }
140
141 /**
142  * octeon_i2c_int_disable - disable the TS interrupt.
143  * @i2c: The struct octeon_i2c.
144  */
145 static void octeon_i2c_int_disable(struct octeon_i2c *i2c)
146 {
147         octeon_i2c_write_int(i2c, 0);
148 }
149
150 /**
151  * octeon_i2c_unblock - unblock the bus.
152  * @i2c: The struct octeon_i2c.
153  *
154  * If there was a reset while a device was driving 0 to bus,
155  * bus is blocked. We toggle it free manually by some clock
156  * cycles and send a stop.
157  */
158 static void octeon_i2c_unblock(struct octeon_i2c *i2c)
159 {
160         int i;
161
162         dev_dbg(i2c->dev, "%s\n", __func__);
163         for (i = 0; i < 9; i++) {
164                 octeon_i2c_write_int(i2c, 0x0);
165                 udelay(5);
166                 octeon_i2c_write_int(i2c, 0x200);
167                 udelay(5);
168         }
169         octeon_i2c_write_int(i2c, 0x300);
170         udelay(5);
171         octeon_i2c_write_int(i2c, 0x100);
172         udelay(5);
173         octeon_i2c_write_int(i2c, 0x0);
174 }
175
176 /**
177  * octeon_i2c_isr - the interrupt service routine.
178  * @int: The irq, unused.
179  * @dev_id: Our struct octeon_i2c.
180  */
181 static irqreturn_t octeon_i2c_isr(int irq, void *dev_id)
182 {
183         struct octeon_i2c *i2c = dev_id;
184
185         octeon_i2c_int_disable(i2c);
186         wake_up_interruptible(&i2c->queue);
187
188         return IRQ_HANDLED;
189 }
190
191
192 static int octeon_i2c_test_iflg(struct octeon_i2c *i2c)
193 {
194         return (octeon_i2c_read_sw(i2c, SW_TWSI_EOP_TWSI_CTL) & TWSI_CTL_IFLG) != 0;
195 }
196
197 /**
198  * octeon_i2c_wait - wait for the IFLG to be set.
199  * @i2c: The struct octeon_i2c.
200  *
201  * Returns 0 on success, otherwise a negative errno.
202  */
203 static int octeon_i2c_wait(struct octeon_i2c *i2c)
204 {
205         int result;
206
207         octeon_i2c_int_enable(i2c);
208
209         result = wait_event_interruptible_timeout(i2c->queue,
210                                                   octeon_i2c_test_iflg(i2c),
211                                                   i2c->adap.timeout);
212
213         octeon_i2c_int_disable(i2c);
214
215         if (result < 0) {
216                 dev_dbg(i2c->dev, "%s: wait interrupted\n", __func__);
217                 return result;
218         } else if (result == 0) {
219                 dev_dbg(i2c->dev, "%s: timeout\n", __func__);
220                 return -ETIMEDOUT;
221         }
222
223         return 0;
224 }
225
226 /**
227  * octeon_i2c_start - send START to the bus.
228  * @i2c: The struct octeon_i2c.
229  *
230  * Returns 0 on success, otherwise a negative errno.
231  */
232 static int octeon_i2c_start(struct octeon_i2c *i2c)
233 {
234         u8 data;
235         int result;
236
237         octeon_i2c_write_sw(i2c, SW_TWSI_EOP_TWSI_CTL,
238                                 TWSI_CTL_ENAB | TWSI_CTL_STA);
239
240         result = octeon_i2c_wait(i2c);
241         if (result) {
242                 if (octeon_i2c_read_sw(i2c, SW_TWSI_EOP_TWSI_STAT) == STAT_IDLE) {
243                         /*
244                          * Controller refused to send start flag May
245                          * be a client is holding SDA low - let's try
246                          * to free it.
247                          */
248                         octeon_i2c_unblock(i2c);
249                         octeon_i2c_write_sw(i2c, SW_TWSI_EOP_TWSI_CTL,
250                                             TWSI_CTL_ENAB | TWSI_CTL_STA);
251
252                         result = octeon_i2c_wait(i2c);
253                 }
254                 if (result)
255                         return result;
256         }
257
258         data = octeon_i2c_read_sw(i2c, SW_TWSI_EOP_TWSI_STAT);
259         if ((data != STAT_START) && (data != STAT_RSTART)) {
260                 dev_err(i2c->dev, "%s: bad status (0x%x)\n", __func__, data);
261                 return -EIO;
262         }
263
264         return 0;
265 }
266
267 /**
268  * octeon_i2c_stop - send STOP to the bus.
269  * @i2c: The struct octeon_i2c.
270  *
271  * Returns 0 on success, otherwise a negative errno.
272  */
273 static int octeon_i2c_stop(struct octeon_i2c *i2c)
274 {
275         u8 data;
276
277         octeon_i2c_write_sw(i2c, SW_TWSI_EOP_TWSI_CTL,
278                             TWSI_CTL_ENAB | TWSI_CTL_STP);
279
280         data = octeon_i2c_read_sw(i2c, SW_TWSI_EOP_TWSI_STAT);
281
282         if (data != STAT_IDLE) {
283                 dev_err(i2c->dev, "%s: bad status(0x%x)\n", __func__, data);
284                 return -EIO;
285         }
286         return 0;
287 }
288
289 /**
290  * octeon_i2c_write - send data to the bus.
291  * @i2c: The struct octeon_i2c.
292  * @target: Target address.
293  * @data: Pointer to the data to be sent.
294  * @length: Length of the data.
295  *
296  * The address is sent over the bus, then the data.
297  *
298  * Returns 0 on success, otherwise a negative errno.
299  */
300 static int octeon_i2c_write(struct octeon_i2c *i2c, int target,
301                             const u8 *data, int length)
302 {
303         int i, result;
304         u8 tmp;
305
306         result = octeon_i2c_start(i2c);
307         if (result)
308                 return result;
309
310         octeon_i2c_write_sw(i2c, SW_TWSI_EOP_TWSI_DATA, target << 1);
311         octeon_i2c_write_sw(i2c, SW_TWSI_EOP_TWSI_CTL, TWSI_CTL_ENAB);
312
313         result = octeon_i2c_wait(i2c);
314         if (result)
315                 return result;
316
317         for (i = 0; i < length; i++) {
318                 tmp = octeon_i2c_read_sw(i2c, SW_TWSI_EOP_TWSI_STAT);
319                 if ((tmp != STAT_TXADDR_ACK) && (tmp != STAT_TXDATA_ACK)) {
320                         dev_err(i2c->dev,
321                                 "%s: bad status before write (0x%x)\n",
322                                 __func__, tmp);
323                         return -EIO;
324                 }
325
326                 octeon_i2c_write_sw(i2c, SW_TWSI_EOP_TWSI_DATA, data[i]);
327                 octeon_i2c_write_sw(i2c, SW_TWSI_EOP_TWSI_CTL, TWSI_CTL_ENAB);
328
329                 result = octeon_i2c_wait(i2c);
330                 if (result)
331                         return result;
332         }
333
334         return 0;
335 }
336
337 /**
338  * octeon_i2c_read - receive data from the bus.
339  * @i2c: The struct octeon_i2c.
340  * @target: Target address.
341  * @data: Pointer to the location to store the datae .
342  * @length: Length of the data.
343  *
344  * The address is sent over the bus, then the data is read.
345  *
346  * Returns 0 on success, otherwise a negative errno.
347  */
348 static int octeon_i2c_read(struct octeon_i2c *i2c, int target,
349                            u8 *data, int length)
350 {
351         int i, result;
352         u8 tmp;
353
354         if (length < 1)
355                 return -EINVAL;
356
357         result = octeon_i2c_start(i2c);
358         if (result)
359                 return result;
360
361         octeon_i2c_write_sw(i2c, SW_TWSI_EOP_TWSI_DATA, (target<<1) | 1);
362         octeon_i2c_write_sw(i2c, SW_TWSI_EOP_TWSI_CTL, TWSI_CTL_ENAB);
363
364         result = octeon_i2c_wait(i2c);
365         if (result)
366                 return result;
367
368         for (i = 0; i < length; i++) {
369                 tmp = octeon_i2c_read_sw(i2c, SW_TWSI_EOP_TWSI_STAT);
370                 if ((tmp != STAT_RXDATA_ACK) && (tmp != STAT_RXADDR_ACK)) {
371                         dev_err(i2c->dev,
372                                 "%s: bad status before read (0x%x)\n",
373                                 __func__, tmp);
374                         return -EIO;
375                 }
376
377                 if (i+1 < length)
378                         octeon_i2c_write_sw(i2c, SW_TWSI_EOP_TWSI_CTL,
379                                                 TWSI_CTL_ENAB | TWSI_CTL_AAK);
380                 else
381                         octeon_i2c_write_sw(i2c, SW_TWSI_EOP_TWSI_CTL,
382                                                 TWSI_CTL_ENAB);
383
384                 result = octeon_i2c_wait(i2c);
385                 if (result)
386                         return result;
387
388                 data[i] = octeon_i2c_read_sw(i2c, SW_TWSI_EOP_TWSI_DATA);
389         }
390         return 0;
391 }
392
393 /**
394  * octeon_i2c_xfer - The driver's master_xfer function.
395  * @adap: Pointer to the i2c_adapter structure.
396  * @msgs: Pointer to the messages to be processed.
397  * @num: Length of the MSGS array.
398  *
399  * Returns the number of messages processed, or a negative errno on
400  * failure.
401  */
402 static int octeon_i2c_xfer(struct i2c_adapter *adap,
403                            struct i2c_msg *msgs,
404                            int num)
405 {
406         struct i2c_msg *pmsg;
407         int i;
408         int ret = 0;
409         struct octeon_i2c *i2c = i2c_get_adapdata(adap);
410
411         for (i = 0; ret == 0 && i < num; i++) {
412                 pmsg = &msgs[i];
413                 dev_dbg(i2c->dev,
414                         "Doing %s %d byte(s) to/from 0x%02x - %d of %d messages\n",
415                          pmsg->flags & I2C_M_RD ? "read" : "write",
416                          pmsg->len, pmsg->addr, i + 1, num);
417                 if (pmsg->flags & I2C_M_RD)
418                         ret = octeon_i2c_read(i2c, pmsg->addr, pmsg->buf,
419                                                 pmsg->len);
420                 else
421                         ret = octeon_i2c_write(i2c, pmsg->addr, pmsg->buf,
422                                                 pmsg->len);
423         }
424         octeon_i2c_stop(i2c);
425
426         return (ret != 0) ? ret : num;
427 }
428
429 static u32 octeon_i2c_functionality(struct i2c_adapter *adap)
430 {
431         return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
432 }
433
434 static const struct i2c_algorithm octeon_i2c_algo = {
435         .master_xfer = octeon_i2c_xfer,
436         .functionality = octeon_i2c_functionality,
437 };
438
439 static struct i2c_adapter octeon_i2c_ops = {
440         .owner = THIS_MODULE,
441         .name = "OCTEON adapter",
442         .algo = &octeon_i2c_algo,
443         .timeout = 2,
444 };
445
446 /**
447  * octeon_i2c_setclock - Calculate and set clock divisors.
448  */
449 static int octeon_i2c_setclock(struct octeon_i2c *i2c)
450 {
451         int tclk, thp_base, inc, thp_idx, mdiv_idx, ndiv_idx, foscl, diff;
452         int thp = 0x18, mdiv = 2, ndiv = 0, delta_hz = 1000000;
453
454         for (ndiv_idx = 0; ndiv_idx < 8 && delta_hz != 0; ndiv_idx++) {
455                 /*
456                  * An mdiv value of less than 2 seems to not work well
457                  * with ds1337 RTCs, so we constrain it to larger
458                  * values.
459                  */
460                 for (mdiv_idx = 15; mdiv_idx >= 2 && delta_hz != 0; mdiv_idx--) {
461                         /*
462                          * For given ndiv and mdiv values check the
463                          * two closest thp values.
464                          */
465                         tclk = i2c->twsi_freq * (mdiv_idx + 1) * 10;
466                         tclk *= (1 << ndiv_idx);
467                         thp_base = (i2c->sys_freq / (tclk * 2)) - 1;
468                         for (inc = 0; inc <= 1; inc++) {
469                                 thp_idx = thp_base + inc;
470                                 if (thp_idx < 5 || thp_idx > 0xff)
471                                         continue;
472
473                                 foscl = i2c->sys_freq / (2 * (thp_idx + 1));
474                                 foscl = foscl / (1 << ndiv_idx);
475                                 foscl = foscl / (mdiv_idx + 1) / 10;
476                                 diff = abs(foscl - i2c->twsi_freq);
477                                 if (diff < delta_hz) {
478                                         delta_hz = diff;
479                                         thp = thp_idx;
480                                         mdiv = mdiv_idx;
481                                         ndiv = ndiv_idx;
482                                 }
483                         }
484                 }
485         }
486         octeon_i2c_write_sw(i2c, SW_TWSI_OP_TWSI_CLK, thp);
487         octeon_i2c_write_sw(i2c, SW_TWSI_EOP_TWSI_CLKCTL, (mdiv << 3) | ndiv);
488
489         return 0;
490 }
491
492 static int octeon_i2c_initlowlevel(struct octeon_i2c *i2c)
493 {
494         u8 status;
495         int tries;
496
497         /* disable high level controller, enable bus access */
498         octeon_i2c_write_sw(i2c, SW_TWSI_EOP_TWSI_CTL, TWSI_CTL_ENAB);
499
500         /* reset controller */
501         octeon_i2c_write_sw(i2c, SW_TWSI_EOP_TWSI_RST, 0);
502
503         for (tries = 10; tries; tries--) {
504                 udelay(1);
505                 status = octeon_i2c_read_sw(i2c, SW_TWSI_EOP_TWSI_STAT);
506                 if (status == STAT_IDLE)
507                         return 0;
508         }
509         dev_err(i2c->dev, "%s: TWSI_RST failed! (0x%x)\n", __func__, status);
510         return -EIO;
511 }
512
513 static int octeon_i2c_probe(struct platform_device *pdev)
514 {
515         int irq, result = 0;
516         struct octeon_i2c *i2c;
517         struct resource *res_mem;
518
519         /* All adaptors have an irq.  */
520         irq = platform_get_irq(pdev, 0);
521         if (irq < 0)
522                 return irq;
523
524         i2c = devm_kzalloc(&pdev->dev, sizeof(*i2c), GFP_KERNEL);
525         if (!i2c) {
526                 dev_err(&pdev->dev, "kzalloc failed\n");
527                 result = -ENOMEM;
528                 goto out;
529         }
530         i2c->dev = &pdev->dev;
531
532         res_mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
533
534         if (res_mem == NULL) {
535                 dev_err(i2c->dev, "found no memory resource\n");
536                 result = -ENXIO;
537                 goto out;
538         }
539         i2c->twsi_phys = res_mem->start;
540         i2c->regsize = resource_size(res_mem);
541
542         /*
543          * "clock-rate" is a legacy binding, the official binding is
544          * "clock-frequency".  Try the official one first and then
545          * fall back if it doesn't exist.
546          */
547         if (of_property_read_u32(pdev->dev.of_node,
548                                  "clock-frequency", &i2c->twsi_freq) &&
549             of_property_read_u32(pdev->dev.of_node,
550                                  "clock-rate", &i2c->twsi_freq)) {
551                 dev_err(i2c->dev,
552                         "no I2C 'clock-rate' or 'clock-frequency' property\n");
553                 result = -ENXIO;
554                 goto out;
555         }
556
557         i2c->sys_freq = octeon_get_io_clock_rate();
558
559         if (!devm_request_mem_region(&pdev->dev, i2c->twsi_phys, i2c->regsize,
560                                       res_mem->name)) {
561                 dev_err(i2c->dev, "request_mem_region failed\n");
562                 goto out;
563         }
564         i2c->twsi_base = devm_ioremap(&pdev->dev, i2c->twsi_phys, i2c->regsize);
565
566         init_waitqueue_head(&i2c->queue);
567
568         i2c->irq = irq;
569
570         result = devm_request_irq(&pdev->dev, i2c->irq,
571                                   octeon_i2c_isr, 0, DRV_NAME, i2c);
572         if (result < 0) {
573                 dev_err(i2c->dev, "failed to attach interrupt\n");
574                 goto out;
575         }
576
577         result = octeon_i2c_initlowlevel(i2c);
578         if (result) {
579                 dev_err(i2c->dev, "init low level failed\n");
580                 goto  out;
581         }
582
583         result = octeon_i2c_setclock(i2c);
584         if (result) {
585                 dev_err(i2c->dev, "clock init failed\n");
586                 goto  out;
587         }
588
589         i2c->adap = octeon_i2c_ops;
590         i2c->adap.dev.parent = &pdev->dev;
591         i2c->adap.dev.of_node = pdev->dev.of_node;
592         i2c_set_adapdata(&i2c->adap, i2c);
593         platform_set_drvdata(pdev, i2c);
594
595         result = i2c_add_adapter(&i2c->adap);
596         if (result < 0) {
597                 dev_err(i2c->dev, "failed to add adapter\n");
598                 goto fail_add;
599         }
600         dev_info(i2c->dev, "version %s\n", DRV_VERSION);
601
602         of_i2c_register_devices(&i2c->adap);
603
604         return 0;
605
606 fail_add:
607         platform_set_drvdata(pdev, NULL);
608 out:
609         return result;
610 };
611
612 static int octeon_i2c_remove(struct platform_device *pdev)
613 {
614         struct octeon_i2c *i2c = platform_get_drvdata(pdev);
615
616         i2c_del_adapter(&i2c->adap);
617         platform_set_drvdata(pdev, NULL);
618         return 0;
619 };
620
621 static struct of_device_id octeon_i2c_match[] = {
622         {
623                 .compatible = "cavium,octeon-3860-twsi",
624         },
625         {},
626 };
627 MODULE_DEVICE_TABLE(of, octeon_i2c_match);
628
629 static struct platform_driver octeon_i2c_driver = {
630         .probe          = octeon_i2c_probe,
631         .remove         = octeon_i2c_remove,
632         .driver         = {
633                 .owner  = THIS_MODULE,
634                 .name   = DRV_NAME,
635                 .of_match_table = octeon_i2c_match,
636         },
637 };
638
639 module_platform_driver(octeon_i2c_driver);
640
641 MODULE_AUTHOR("Michael Lawnick <michael.lawnick.ext@nsn.com>");
642 MODULE_DESCRIPTION("I2C-Bus adapter for Cavium OCTEON processors");
643 MODULE_LICENSE("GPL");
644 MODULE_VERSION(DRV_VERSION);