Add the rt linux 4.1.3-rt3 as base
[kvmfornfv.git] / kernel / 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/delay.h>
19 #include <linux/sched.h>
20 #include <linux/slab.h>
21 #include <linux/i2c.h>
22 #include <linux/io.h>
23 #include <linux/of.h>
24
25 #include <asm/octeon/octeon.h>
26
27 #define DRV_NAME "i2c-octeon"
28
29 /* The previous out-of-tree version was implicitly version 1.0. */
30 #define DRV_VERSION     "2.0"
31
32 /* register offsets */
33 #define SW_TWSI  0x00
34 #define TWSI_INT 0x10
35
36 /* Controller command patterns */
37 #define SW_TWSI_V               0x8000000000000000ull
38 #define SW_TWSI_EOP_TWSI_DATA   0x0C00000100000000ull
39 #define SW_TWSI_EOP_TWSI_CTL    0x0C00000200000000ull
40 #define SW_TWSI_EOP_TWSI_CLKCTL 0x0C00000300000000ull
41 #define SW_TWSI_EOP_TWSI_STAT   0x0C00000300000000ull
42 #define SW_TWSI_EOP_TWSI_RST    0x0C00000700000000ull
43 #define SW_TWSI_OP_TWSI_CLK     0x0800000000000000ull
44 #define SW_TWSI_R               0x0100000000000000ull
45
46 /* Controller command and status bits */
47 #define TWSI_CTL_CE   0x80
48 #define TWSI_CTL_ENAB 0x40
49 #define TWSI_CTL_STA  0x20
50 #define TWSI_CTL_STP  0x10
51 #define TWSI_CTL_IFLG 0x08
52 #define TWSI_CTL_AAK  0x04
53
54 /* Some status values */
55 #define STAT_START      0x08
56 #define STAT_RSTART     0x10
57 #define STAT_TXADDR_ACK 0x18
58 #define STAT_TXDATA_ACK 0x28
59 #define STAT_RXADDR_ACK 0x40
60 #define STAT_RXDATA_ACK 0x50
61 #define STAT_IDLE       0xF8
62
63 struct octeon_i2c {
64         wait_queue_head_t queue;
65         struct i2c_adapter adap;
66         int irq;
67         u32 twsi_freq;
68         int sys_freq;
69         resource_size_t twsi_phys;
70         void __iomem *twsi_base;
71         resource_size_t regsize;
72         struct device *dev;
73 };
74
75 /**
76  * octeon_i2c_write_sw - write an I2C core register.
77  * @i2c: The struct octeon_i2c.
78  * @eop_reg: Register selector.
79  * @data: Value to be written.
80  *
81  * The I2C core registers are accessed indirectly via the SW_TWSI CSR.
82  */
83 static void octeon_i2c_write_sw(struct octeon_i2c *i2c,
84                                 u64 eop_reg,
85                                 u8 data)
86 {
87         u64 tmp;
88
89         __raw_writeq(SW_TWSI_V | eop_reg | data, i2c->twsi_base + SW_TWSI);
90         do {
91                 tmp = __raw_readq(i2c->twsi_base + SW_TWSI);
92         } while ((tmp & SW_TWSI_V) != 0);
93 }
94
95 /**
96  * octeon_i2c_read_sw - write an I2C core register.
97  * @i2c: The struct octeon_i2c.
98  * @eop_reg: Register selector.
99  *
100  * Returns the data.
101  *
102  * The I2C core registers are accessed indirectly via the SW_TWSI CSR.
103  */
104 static u8 octeon_i2c_read_sw(struct octeon_i2c *i2c, u64 eop_reg)
105 {
106         u64 tmp;
107
108         __raw_writeq(SW_TWSI_V | eop_reg | SW_TWSI_R, i2c->twsi_base + SW_TWSI);
109         do {
110                 tmp = __raw_readq(i2c->twsi_base + SW_TWSI);
111         } while ((tmp & SW_TWSI_V) != 0);
112
113         return tmp & 0xFF;
114 }
115
116 /**
117  * octeon_i2c_write_int - write the TWSI_INT register
118  * @i2c: The struct octeon_i2c.
119  * @data: Value to be written.
120  */
121 static void octeon_i2c_write_int(struct octeon_i2c *i2c, u64 data)
122 {
123         __raw_writeq(data, i2c->twsi_base + TWSI_INT);
124         __raw_readq(i2c->twsi_base + TWSI_INT);
125 }
126
127 /**
128  * octeon_i2c_int_enable - enable the TS interrupt.
129  * @i2c: The struct octeon_i2c.
130  *
131  * The interrupt will be asserted when there is non-STAT_IDLE state in
132  * the SW_TWSI_EOP_TWSI_STAT register.
133  */
134 static void octeon_i2c_int_enable(struct octeon_i2c *i2c)
135 {
136         octeon_i2c_write_int(i2c, 0x40);
137 }
138
139 /**
140  * octeon_i2c_int_disable - disable the TS interrupt.
141  * @i2c: The struct octeon_i2c.
142  */
143 static void octeon_i2c_int_disable(struct octeon_i2c *i2c)
144 {
145         octeon_i2c_write_int(i2c, 0);
146 }
147
148 /**
149  * octeon_i2c_unblock - unblock the bus.
150  * @i2c: The struct octeon_i2c.
151  *
152  * If there was a reset while a device was driving 0 to bus,
153  * bus is blocked. We toggle it free manually by some clock
154  * cycles and send a stop.
155  */
156 static void octeon_i2c_unblock(struct octeon_i2c *i2c)
157 {
158         int i;
159
160         dev_dbg(i2c->dev, "%s\n", __func__);
161         for (i = 0; i < 9; i++) {
162                 octeon_i2c_write_int(i2c, 0x0);
163                 udelay(5);
164                 octeon_i2c_write_int(i2c, 0x200);
165                 udelay(5);
166         }
167         octeon_i2c_write_int(i2c, 0x300);
168         udelay(5);
169         octeon_i2c_write_int(i2c, 0x100);
170         udelay(5);
171         octeon_i2c_write_int(i2c, 0x0);
172 }
173
174 /**
175  * octeon_i2c_isr - the interrupt service routine.
176  * @int: The irq, unused.
177  * @dev_id: Our struct octeon_i2c.
178  */
179 static irqreturn_t octeon_i2c_isr(int irq, void *dev_id)
180 {
181         struct octeon_i2c *i2c = dev_id;
182
183         octeon_i2c_int_disable(i2c);
184         wake_up(&i2c->queue);
185
186         return IRQ_HANDLED;
187 }
188
189
190 static int octeon_i2c_test_iflg(struct octeon_i2c *i2c)
191 {
192         return (octeon_i2c_read_sw(i2c, SW_TWSI_EOP_TWSI_CTL) & TWSI_CTL_IFLG) != 0;
193 }
194
195 /**
196  * octeon_i2c_wait - wait for the IFLG to be set.
197  * @i2c: The struct octeon_i2c.
198  *
199  * Returns 0 on success, otherwise a negative errno.
200  */
201 static int octeon_i2c_wait(struct octeon_i2c *i2c)
202 {
203         int result;
204
205         octeon_i2c_int_enable(i2c);
206
207         result = wait_event_timeout(i2c->queue,
208                                         octeon_i2c_test_iflg(i2c),
209                                         i2c->adap.timeout);
210
211         octeon_i2c_int_disable(i2c);
212
213         if (result < 0) {
214                 dev_dbg(i2c->dev, "%s: wait interrupted\n", __func__);
215                 return result;
216         } else if (result == 0) {
217                 dev_dbg(i2c->dev, "%s: timeout\n", __func__);
218                 return -ETIMEDOUT;
219         }
220
221         return 0;
222 }
223
224 /**
225  * octeon_i2c_start - send START to the bus.
226  * @i2c: The struct octeon_i2c.
227  *
228  * Returns 0 on success, otherwise a negative errno.
229  */
230 static int octeon_i2c_start(struct octeon_i2c *i2c)
231 {
232         u8 data;
233         int result;
234
235         octeon_i2c_write_sw(i2c, SW_TWSI_EOP_TWSI_CTL,
236                                 TWSI_CTL_ENAB | TWSI_CTL_STA);
237
238         result = octeon_i2c_wait(i2c);
239         if (result) {
240                 if (octeon_i2c_read_sw(i2c, SW_TWSI_EOP_TWSI_STAT) == STAT_IDLE) {
241                         /*
242                          * Controller refused to send start flag May
243                          * be a client is holding SDA low - let's try
244                          * to free it.
245                          */
246                         octeon_i2c_unblock(i2c);
247                         octeon_i2c_write_sw(i2c, SW_TWSI_EOP_TWSI_CTL,
248                                             TWSI_CTL_ENAB | TWSI_CTL_STA);
249
250                         result = octeon_i2c_wait(i2c);
251                 }
252                 if (result)
253                         return result;
254         }
255
256         data = octeon_i2c_read_sw(i2c, SW_TWSI_EOP_TWSI_STAT);
257         if ((data != STAT_START) && (data != STAT_RSTART)) {
258                 dev_err(i2c->dev, "%s: bad status (0x%x)\n", __func__, data);
259                 return -EIO;
260         }
261
262         return 0;
263 }
264
265 /**
266  * octeon_i2c_stop - send STOP to the bus.
267  * @i2c: The struct octeon_i2c.
268  *
269  * Returns 0 on success, otherwise a negative errno.
270  */
271 static int octeon_i2c_stop(struct octeon_i2c *i2c)
272 {
273         u8 data;
274
275         octeon_i2c_write_sw(i2c, SW_TWSI_EOP_TWSI_CTL,
276                             TWSI_CTL_ENAB | TWSI_CTL_STP);
277
278         data = octeon_i2c_read_sw(i2c, SW_TWSI_EOP_TWSI_STAT);
279
280         if (data != STAT_IDLE) {
281                 dev_err(i2c->dev, "%s: bad status(0x%x)\n", __func__, data);
282                 return -EIO;
283         }
284         return 0;
285 }
286
287 /**
288  * octeon_i2c_write - send data to the bus.
289  * @i2c: The struct octeon_i2c.
290  * @target: Target address.
291  * @data: Pointer to the data to be sent.
292  * @length: Length of the data.
293  *
294  * The address is sent over the bus, then the data.
295  *
296  * Returns 0 on success, otherwise a negative errno.
297  */
298 static int octeon_i2c_write(struct octeon_i2c *i2c, int target,
299                             const u8 *data, int length)
300 {
301         int i, result;
302         u8 tmp;
303
304         result = octeon_i2c_start(i2c);
305         if (result)
306                 return result;
307
308         octeon_i2c_write_sw(i2c, SW_TWSI_EOP_TWSI_DATA, target << 1);
309         octeon_i2c_write_sw(i2c, SW_TWSI_EOP_TWSI_CTL, TWSI_CTL_ENAB);
310
311         result = octeon_i2c_wait(i2c);
312         if (result)
313                 return result;
314
315         for (i = 0; i < length; i++) {
316                 tmp = octeon_i2c_read_sw(i2c, SW_TWSI_EOP_TWSI_STAT);
317                 if ((tmp != STAT_TXADDR_ACK) && (tmp != STAT_TXDATA_ACK)) {
318                         dev_err(i2c->dev,
319                                 "%s: bad status before write (0x%x)\n",
320                                 __func__, tmp);
321                         return -EIO;
322                 }
323
324                 octeon_i2c_write_sw(i2c, SW_TWSI_EOP_TWSI_DATA, data[i]);
325                 octeon_i2c_write_sw(i2c, SW_TWSI_EOP_TWSI_CTL, TWSI_CTL_ENAB);
326
327                 result = octeon_i2c_wait(i2c);
328                 if (result)
329                         return result;
330         }
331
332         return 0;
333 }
334
335 /**
336  * octeon_i2c_read - receive data from the bus.
337  * @i2c: The struct octeon_i2c.
338  * @target: Target address.
339  * @data: Pointer to the location to store the datae .
340  * @length: Length of the data.
341  *
342  * The address is sent over the bus, then the data is read.
343  *
344  * Returns 0 on success, otherwise a negative errno.
345  */
346 static int octeon_i2c_read(struct octeon_i2c *i2c, int target,
347                            u8 *data, int length)
348 {
349         int i, result;
350         u8 tmp;
351
352         if (length < 1)
353                 return -EINVAL;
354
355         result = octeon_i2c_start(i2c);
356         if (result)
357                 return result;
358
359         octeon_i2c_write_sw(i2c, SW_TWSI_EOP_TWSI_DATA, (target<<1) | 1);
360         octeon_i2c_write_sw(i2c, SW_TWSI_EOP_TWSI_CTL, TWSI_CTL_ENAB);
361
362         result = octeon_i2c_wait(i2c);
363         if (result)
364                 return result;
365
366         for (i = 0; i < length; i++) {
367                 tmp = octeon_i2c_read_sw(i2c, SW_TWSI_EOP_TWSI_STAT);
368                 if ((tmp != STAT_RXDATA_ACK) && (tmp != STAT_RXADDR_ACK)) {
369                         dev_err(i2c->dev,
370                                 "%s: bad status before read (0x%x)\n",
371                                 __func__, tmp);
372                         return -EIO;
373                 }
374
375                 if (i+1 < length)
376                         octeon_i2c_write_sw(i2c, SW_TWSI_EOP_TWSI_CTL,
377                                                 TWSI_CTL_ENAB | TWSI_CTL_AAK);
378                 else
379                         octeon_i2c_write_sw(i2c, SW_TWSI_EOP_TWSI_CTL,
380                                                 TWSI_CTL_ENAB);
381
382                 result = octeon_i2c_wait(i2c);
383                 if (result)
384                         return result;
385
386                 data[i] = octeon_i2c_read_sw(i2c, SW_TWSI_EOP_TWSI_DATA);
387         }
388         return 0;
389 }
390
391 /**
392  * octeon_i2c_xfer - The driver's master_xfer function.
393  * @adap: Pointer to the i2c_adapter structure.
394  * @msgs: Pointer to the messages to be processed.
395  * @num: Length of the MSGS array.
396  *
397  * Returns the number of messages processed, or a negative errno on
398  * failure.
399  */
400 static int octeon_i2c_xfer(struct i2c_adapter *adap,
401                            struct i2c_msg *msgs,
402                            int num)
403 {
404         struct i2c_msg *pmsg;
405         int i;
406         int ret = 0;
407         struct octeon_i2c *i2c = i2c_get_adapdata(adap);
408
409         for (i = 0; ret == 0 && i < num; i++) {
410                 pmsg = &msgs[i];
411                 dev_dbg(i2c->dev,
412                         "Doing %s %d byte(s) to/from 0x%02x - %d of %d messages\n",
413                          pmsg->flags & I2C_M_RD ? "read" : "write",
414                          pmsg->len, pmsg->addr, i + 1, num);
415                 if (pmsg->flags & I2C_M_RD)
416                         ret = octeon_i2c_read(i2c, pmsg->addr, pmsg->buf,
417                                                 pmsg->len);
418                 else
419                         ret = octeon_i2c_write(i2c, pmsg->addr, pmsg->buf,
420                                                 pmsg->len);
421         }
422         octeon_i2c_stop(i2c);
423
424         return (ret != 0) ? ret : num;
425 }
426
427 static u32 octeon_i2c_functionality(struct i2c_adapter *adap)
428 {
429         return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
430 }
431
432 static const struct i2c_algorithm octeon_i2c_algo = {
433         .master_xfer = octeon_i2c_xfer,
434         .functionality = octeon_i2c_functionality,
435 };
436
437 static struct i2c_adapter octeon_i2c_ops = {
438         .owner = THIS_MODULE,
439         .name = "OCTEON adapter",
440         .algo = &octeon_i2c_algo,
441         .timeout = HZ / 50,
442 };
443
444 /**
445  * octeon_i2c_setclock - Calculate and set clock divisors.
446  */
447 static int octeon_i2c_setclock(struct octeon_i2c *i2c)
448 {
449         int tclk, thp_base, inc, thp_idx, mdiv_idx, ndiv_idx, foscl, diff;
450         int thp = 0x18, mdiv = 2, ndiv = 0, delta_hz = 1000000;
451
452         for (ndiv_idx = 0; ndiv_idx < 8 && delta_hz != 0; ndiv_idx++) {
453                 /*
454                  * An mdiv value of less than 2 seems to not work well
455                  * with ds1337 RTCs, so we constrain it to larger
456                  * values.
457                  */
458                 for (mdiv_idx = 15; mdiv_idx >= 2 && delta_hz != 0; mdiv_idx--) {
459                         /*
460                          * For given ndiv and mdiv values check the
461                          * two closest thp values.
462                          */
463                         tclk = i2c->twsi_freq * (mdiv_idx + 1) * 10;
464                         tclk *= (1 << ndiv_idx);
465                         thp_base = (i2c->sys_freq / (tclk * 2)) - 1;
466                         for (inc = 0; inc <= 1; inc++) {
467                                 thp_idx = thp_base + inc;
468                                 if (thp_idx < 5 || thp_idx > 0xff)
469                                         continue;
470
471                                 foscl = i2c->sys_freq / (2 * (thp_idx + 1));
472                                 foscl = foscl / (1 << ndiv_idx);
473                                 foscl = foscl / (mdiv_idx + 1) / 10;
474                                 diff = abs(foscl - i2c->twsi_freq);
475                                 if (diff < delta_hz) {
476                                         delta_hz = diff;
477                                         thp = thp_idx;
478                                         mdiv = mdiv_idx;
479                                         ndiv = ndiv_idx;
480                                 }
481                         }
482                 }
483         }
484         octeon_i2c_write_sw(i2c, SW_TWSI_OP_TWSI_CLK, thp);
485         octeon_i2c_write_sw(i2c, SW_TWSI_EOP_TWSI_CLKCTL, (mdiv << 3) | ndiv);
486
487         return 0;
488 }
489
490 static int octeon_i2c_initlowlevel(struct octeon_i2c *i2c)
491 {
492         u8 status;
493         int tries;
494
495         /* disable high level controller, enable bus access */
496         octeon_i2c_write_sw(i2c, SW_TWSI_EOP_TWSI_CTL, TWSI_CTL_ENAB);
497
498         /* reset controller */
499         octeon_i2c_write_sw(i2c, SW_TWSI_EOP_TWSI_RST, 0);
500
501         for (tries = 10; tries; tries--) {
502                 udelay(1);
503                 status = octeon_i2c_read_sw(i2c, SW_TWSI_EOP_TWSI_STAT);
504                 if (status == STAT_IDLE)
505                         return 0;
506         }
507         dev_err(i2c->dev, "%s: TWSI_RST failed! (0x%x)\n", __func__, status);
508         return -EIO;
509 }
510
511 static int octeon_i2c_probe(struct platform_device *pdev)
512 {
513         int irq, result = 0;
514         struct octeon_i2c *i2c;
515         struct resource *res_mem;
516
517         /* All adaptors have an irq.  */
518         irq = platform_get_irq(pdev, 0);
519         if (irq < 0)
520                 return irq;
521
522         i2c = devm_kzalloc(&pdev->dev, sizeof(*i2c), GFP_KERNEL);
523         if (!i2c) {
524                 dev_err(&pdev->dev, "kzalloc failed\n");
525                 result = -ENOMEM;
526                 goto out;
527         }
528         i2c->dev = &pdev->dev;
529
530         res_mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
531
532         if (res_mem == NULL) {
533                 dev_err(i2c->dev, "found no memory resource\n");
534                 result = -ENXIO;
535                 goto out;
536         }
537         i2c->twsi_phys = res_mem->start;
538         i2c->regsize = resource_size(res_mem);
539
540         /*
541          * "clock-rate" is a legacy binding, the official binding is
542          * "clock-frequency".  Try the official one first and then
543          * fall back if it doesn't exist.
544          */
545         if (of_property_read_u32(pdev->dev.of_node,
546                                  "clock-frequency", &i2c->twsi_freq) &&
547             of_property_read_u32(pdev->dev.of_node,
548                                  "clock-rate", &i2c->twsi_freq)) {
549                 dev_err(i2c->dev,
550                         "no I2C 'clock-rate' or 'clock-frequency' property\n");
551                 result = -ENXIO;
552                 goto out;
553         }
554
555         i2c->sys_freq = octeon_get_io_clock_rate();
556
557         if (!devm_request_mem_region(&pdev->dev, i2c->twsi_phys, i2c->regsize,
558                                       res_mem->name)) {
559                 dev_err(i2c->dev, "request_mem_region failed\n");
560                 goto out;
561         }
562         i2c->twsi_base = devm_ioremap(&pdev->dev, i2c->twsi_phys, i2c->regsize);
563
564         init_waitqueue_head(&i2c->queue);
565
566         i2c->irq = irq;
567
568         result = devm_request_irq(&pdev->dev, i2c->irq,
569                                   octeon_i2c_isr, 0, DRV_NAME, i2c);
570         if (result < 0) {
571                 dev_err(i2c->dev, "failed to attach interrupt\n");
572                 goto out;
573         }
574
575         result = octeon_i2c_initlowlevel(i2c);
576         if (result) {
577                 dev_err(i2c->dev, "init low level failed\n");
578                 goto  out;
579         }
580
581         result = octeon_i2c_setclock(i2c);
582         if (result) {
583                 dev_err(i2c->dev, "clock init failed\n");
584                 goto  out;
585         }
586
587         i2c->adap = octeon_i2c_ops;
588         i2c->adap.dev.parent = &pdev->dev;
589         i2c->adap.dev.of_node = pdev->dev.of_node;
590         i2c_set_adapdata(&i2c->adap, i2c);
591         platform_set_drvdata(pdev, i2c);
592
593         result = i2c_add_adapter(&i2c->adap);
594         if (result < 0) {
595                 dev_err(i2c->dev, "failed to add adapter\n");
596                 goto out;
597         }
598         dev_info(i2c->dev, "version %s\n", DRV_VERSION);
599
600         return 0;
601
602 out:
603         return result;
604 };
605
606 static int octeon_i2c_remove(struct platform_device *pdev)
607 {
608         struct octeon_i2c *i2c = platform_get_drvdata(pdev);
609
610         i2c_del_adapter(&i2c->adap);
611         return 0;
612 };
613
614 static struct of_device_id octeon_i2c_match[] = {
615         {
616                 .compatible = "cavium,octeon-3860-twsi",
617         },
618         {},
619 };
620 MODULE_DEVICE_TABLE(of, octeon_i2c_match);
621
622 static struct platform_driver octeon_i2c_driver = {
623         .probe          = octeon_i2c_probe,
624         .remove         = octeon_i2c_remove,
625         .driver         = {
626                 .name   = DRV_NAME,
627                 .of_match_table = octeon_i2c_match,
628         },
629 };
630
631 module_platform_driver(octeon_i2c_driver);
632
633 MODULE_AUTHOR("Michael Lawnick <michael.lawnick.ext@nsn.com>");
634 MODULE_DESCRIPTION("I2C-Bus adapter for Cavium OCTEON processors");
635 MODULE_LICENSE("GPL");
636 MODULE_VERSION(DRV_VERSION);