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1/*
2 * (C) Copyright 2009-2010
3 * Nokia Siemens Networks, michael.lawnick.ext@nsn.com
4 *
5 * Portions Copyright (C) 2010 - 2016 Cavium, Inc.
6 *
7 * This file contains the shared part of the driver for the i2c adapter in
8 * Cavium Networks' OCTEON processors and ThunderX SOCs.
9 *
10 * This file is licensed under the terms of the GNU General Public
11 * License version 2. This program is licensed "as is" without any
12 * warranty of any kind, whether express or implied.
13 */
14
15#include <linux/delay.h>
16#include <linux/i2c.h>
17#include <linux/interrupt.h>
18#include <linux/kernel.h>
19#include <linux/module.h>
20#include <linux/pci.h>
21
22#include "i2c-octeon-core.h"
23
24#define INITIAL_DELTA_HZ 1000000
25#define TWSI_MASTER_CLK_REG_DEF_VAL 0x18
26#define TWSI_MASTER_CLK_REG_OTX2_VAL 0x3
27
28/* interrupt service routine */
29irqreturn_t octeon_i2c_isr(int irq, void *dev_id)
30{
31 struct octeon_i2c *i2c = dev_id;
32
33 i2c->int_disable(i2c);
34 wake_up(&i2c->queue);
35
36 return IRQ_HANDLED;
37}
38
39static bool octeon_i2c_test_iflg(struct octeon_i2c *i2c)
40{
41 return (octeon_i2c_ctl_read(i2c) & TWSI_CTL_IFLG);
42}
43
44/**
45 * octeon_i2c_wait - wait for the IFLG to be set
46 * @i2c: The struct octeon_i2c
47 *
48 * Returns 0 on success, otherwise a negative errno.
49 */
50static int octeon_i2c_wait(struct octeon_i2c *i2c)
51{
52 long time_left;
53
54 /*
55 * Some chip revisions don't assert the irq in the interrupt
56 * controller. So we must poll for the IFLG change.
57 */
58 if (i2c->broken_irq_mode) {
59 u64 end = get_jiffies_64() + i2c->adap.timeout;
60
61 while (!octeon_i2c_test_iflg(i2c) &&
62 time_before64(get_jiffies_64(), end))
63 usleep_range(I2C_OCTEON_EVENT_WAIT / 2, I2C_OCTEON_EVENT_WAIT);
64
65 return octeon_i2c_test_iflg(i2c) ? 0 : -ETIMEDOUT;
66 }
67
68 i2c->int_enable(i2c);
69 time_left = wait_event_timeout(i2c->queue, octeon_i2c_test_iflg(i2c),
70 i2c->adap.timeout);
71 i2c->int_disable(i2c);
72
73 if (i2c->broken_irq_check && !time_left &&
74 octeon_i2c_test_iflg(i2c)) {
75 dev_err(i2c->dev, "broken irq connection detected, switching to polling mode.\n");
76 i2c->broken_irq_mode = true;
77 return 0;
78 }
79
80 if (!time_left)
81 return -ETIMEDOUT;
82
83 return 0;
84}
85
86static bool octeon_i2c_hlc_test_valid(struct octeon_i2c *i2c)
87{
88 return (__raw_readq(i2c->twsi_base + OCTEON_REG_SW_TWSI(i2c)) & SW_TWSI_V) == 0;
89}
90
91static void octeon_i2c_hlc_int_clear(struct octeon_i2c *i2c)
92{
93 /* clear ST/TS events, listen for neither */
94 octeon_i2c_write_int(i2c, TWSI_INT_ST_INT | TWSI_INT_TS_INT);
95}
96
97/*
98 * Cleanup low-level state & enable high-level controller.
99 */
100static void octeon_i2c_hlc_enable(struct octeon_i2c *i2c)
101{
102 int try = 0;
103 u64 val;
104
105 if (i2c->hlc_enabled)
106 return;
107 i2c->hlc_enabled = true;
108
109 while (1) {
110 val = octeon_i2c_ctl_read(i2c);
111 if (!(val & (TWSI_CTL_STA | TWSI_CTL_STP)))
112 break;
113
114 /* clear IFLG event */
115 if (val & TWSI_CTL_IFLG)
116 octeon_i2c_ctl_write(i2c, TWSI_CTL_ENAB);
117
118 if (try++ > 100) {
119 pr_err("%s: giving up\n", __func__);
120 break;
121 }
122
123 /* spin until any start/stop has finished */
124 udelay(10);
125 }
126 octeon_i2c_ctl_write(i2c, TWSI_CTL_CE | TWSI_CTL_AAK | TWSI_CTL_ENAB);
127}
128
129static void octeon_i2c_hlc_disable(struct octeon_i2c *i2c)
130{
131 if (!i2c->hlc_enabled)
132 return;
133
134 i2c->hlc_enabled = false;
135 octeon_i2c_ctl_write(i2c, TWSI_CTL_ENAB);
136}
137
138/**
139 * octeon_i2c_hlc_wait - wait for an HLC operation to complete
140 * @i2c: The struct octeon_i2c
141 *
142 * Returns 0 on success, otherwise -ETIMEDOUT.
143 */
144static int octeon_i2c_hlc_wait(struct octeon_i2c *i2c)
145{
146 int time_left;
147
148 /*
149 * Some cn38xx boards don't assert the irq in the interrupt
150 * controller. So we must poll for the valid bit change.
151 */
152 if (i2c->broken_irq_mode) {
153 u64 end = get_jiffies_64() + i2c->adap.timeout;
154
155 while (!octeon_i2c_hlc_test_valid(i2c) &&
156 time_before64(get_jiffies_64(), end))
157 usleep_range(I2C_OCTEON_EVENT_WAIT / 2, I2C_OCTEON_EVENT_WAIT);
158
159 return octeon_i2c_hlc_test_valid(i2c) ? 0 : -ETIMEDOUT;
160 }
161
162 i2c->hlc_int_enable(i2c);
163 time_left = wait_event_timeout(i2c->queue,
164 octeon_i2c_hlc_test_valid(i2c),
165 i2c->adap.timeout);
166 i2c->hlc_int_disable(i2c);
167 if (!time_left)
168 octeon_i2c_hlc_int_clear(i2c);
169
170 if (i2c->broken_irq_check && !time_left &&
171 octeon_i2c_hlc_test_valid(i2c)) {
172 dev_err(i2c->dev, "broken irq connection detected, switching to polling mode.\n");
173 i2c->broken_irq_mode = true;
174 return 0;
175 }
176
177 if (!time_left)
178 return -ETIMEDOUT;
179 return 0;
180}
181
182static int octeon_i2c_check_status(struct octeon_i2c *i2c, int final_read)
183{
184 u8 stat;
185 u64 mode;
186
187 /*
188 * This is ugly... in HLC mode the status is not in the status register
189 * but in the lower 8 bits of OCTEON_REG_SW_TWSI.
190 */
191 if (i2c->hlc_enabled)
192 stat = __raw_readq(i2c->twsi_base + OCTEON_REG_SW_TWSI(i2c));
193 else
194 stat = octeon_i2c_stat_read(i2c);
195
196 switch (stat) {
197 /* Everything is fine */
198 case STAT_IDLE:
199 case STAT_AD2W_ACK:
200 case STAT_RXADDR_ACK:
201 case STAT_TXADDR_ACK:
202 case STAT_TXDATA_ACK:
203 return 0;
204
205 /* ACK allowed on pre-terminal bytes only */
206 case STAT_RXDATA_ACK:
207 if (!final_read)
208 return 0;
209 return -EIO;
210
211 /* NAK allowed on terminal byte only */
212 case STAT_RXDATA_NAK:
213 if (final_read)
214 return 0;
215 return -EIO;
216
217 /* Arbitration lost */
218 case STAT_LOST_ARB_38:
219 case STAT_LOST_ARB_68:
220 case STAT_LOST_ARB_78:
221 case STAT_LOST_ARB_B0:
222 return -EAGAIN;
223
224 /* Being addressed as local target, should back off & listen */
225 case STAT_SLAVE_60:
226 case STAT_SLAVE_70:
227 case STAT_GENDATA_ACK:
228 case STAT_GENDATA_NAK:
229 return -EOPNOTSUPP;
230
231 /* Core busy as local target */
232 case STAT_SLAVE_80:
233 case STAT_SLAVE_88:
234 case STAT_SLAVE_A0:
235 case STAT_SLAVE_A8:
236 case STAT_SLAVE_LOST:
237 case STAT_SLAVE_NAK:
238 case STAT_SLAVE_ACK:
239 return -EOPNOTSUPP;
240
241 case STAT_TXDATA_NAK:
242 case STAT_BUS_ERROR:
243 return -EIO;
244 case STAT_TXADDR_NAK:
245 case STAT_RXADDR_NAK:
246 case STAT_AD2W_NAK:
247 return -ENXIO;
248
249 case STAT_WDOG_TOUT:
250 mode = __raw_readq(i2c->twsi_base + OCTEON_REG_MODE(i2c));
251 /* Set BUS_MON_RST to reset bus monitor */
252 mode |= BUS_MON_RST_MASK;
253 octeon_i2c_writeq_flush(mode, i2c->twsi_base + OCTEON_REG_MODE(i2c));
254 return -EIO;
255 default:
256 dev_err(i2c->dev, "unhandled state: %d\n", stat);
257 return -EIO;
258 }
259}
260
261static int octeon_i2c_recovery(struct octeon_i2c *i2c)
262{
263 int ret;
264
265 ret = i2c_recover_bus(&i2c->adap);
266 if (ret)
267 /* recover failed, try hardware re-init */
268 ret = octeon_i2c_init_lowlevel(i2c);
269 return ret;
270}
271
272/**
273 * octeon_i2c_start - send START to the bus
274 * @i2c: The struct octeon_i2c
275 *
276 * Returns 0 on success, otherwise a negative errno.
277 */
278static int octeon_i2c_start(struct octeon_i2c *i2c)
279{
280 int ret;
281 u8 stat;
282
283 octeon_i2c_hlc_disable(i2c);
284
285 octeon_i2c_ctl_write(i2c, TWSI_CTL_ENAB | TWSI_CTL_STA);
286 ret = octeon_i2c_wait(i2c);
287 if (ret)
288 goto error;
289
290 stat = octeon_i2c_stat_read(i2c);
291 if (stat == STAT_START || stat == STAT_REP_START)
292 /* START successful, bail out */
293 return 0;
294
295error:
296 /* START failed, try to recover */
297 ret = octeon_i2c_recovery(i2c);
298 return (ret) ? ret : -EAGAIN;
299}
300
301/* send STOP to the bus */
302static void octeon_i2c_stop(struct octeon_i2c *i2c)
303{
304 octeon_i2c_ctl_write(i2c, TWSI_CTL_ENAB | TWSI_CTL_STP);
305}
306
307/**
308 * octeon_i2c_read - receive data from the bus via low-level controller
309 * @i2c: The struct octeon_i2c
310 * @target: Target address
311 * @data: Pointer to the location to store the data
312 * @rlength: Length of the data
313 * @recv_len: flag for length byte
314 *
315 * The address is sent over the bus, then the data is read.
316 *
317 * Returns 0 on success, otherwise a negative errno.
318 */
319static int octeon_i2c_read(struct octeon_i2c *i2c, int target,
320 u8 *data, u16 *rlength, bool recv_len)
321{
322 int i, result, length = *rlength;
323 bool final_read = false;
324
325 octeon_i2c_data_write(i2c, (target << 1) | 1);
326 octeon_i2c_ctl_write(i2c, TWSI_CTL_ENAB);
327
328 result = octeon_i2c_wait(i2c);
329 if (result)
330 return result;
331
332 /* address OK ? */
333 result = octeon_i2c_check_status(i2c, false);
334 if (result)
335 return result;
336
337 for (i = 0; i < length; i++) {
338 /*
339 * For the last byte to receive TWSI_CTL_AAK must not be set.
340 *
341 * A special case is I2C_M_RECV_LEN where we don't know the
342 * additional length yet. If recv_len is set we assume we're
343 * not reading the final byte and therefore need to set
344 * TWSI_CTL_AAK.
345 */
346 if ((i + 1 == length) && !(recv_len && i == 0))
347 final_read = true;
348
349 /* clear iflg to allow next event */
350 if (final_read)
351 octeon_i2c_ctl_write(i2c, TWSI_CTL_ENAB);
352 else
353 octeon_i2c_ctl_write(i2c, TWSI_CTL_ENAB | TWSI_CTL_AAK);
354
355 result = octeon_i2c_wait(i2c);
356 if (result)
357 return result;
358
359 data[i] = octeon_i2c_data_read(i2c, &result);
360 if (result)
361 return result;
362 if (recv_len && i == 0) {
363 if (data[i] > I2C_SMBUS_BLOCK_MAX)
364 return -EPROTO;
365 length += data[i];
366 }
367
368 result = octeon_i2c_check_status(i2c, final_read);
369 if (result)
370 return result;
371 }
372 *rlength = length;
373 return 0;
374}
375
376/**
377 * octeon_i2c_write - send data to the bus via low-level controller
378 * @i2c: The struct octeon_i2c
379 * @target: Target address
380 * @data: Pointer to the data to be sent
381 * @length: Length of the data
382 *
383 * The address is sent over the bus, then the data.
384 *
385 * Returns 0 on success, otherwise a negative errno.
386 */
387static int octeon_i2c_write(struct octeon_i2c *i2c, int target,
388 const u8 *data, int length)
389{
390 int i, result;
391
392 octeon_i2c_data_write(i2c, target << 1);
393 octeon_i2c_ctl_write(i2c, TWSI_CTL_ENAB);
394
395 result = octeon_i2c_wait(i2c);
396 if (result)
397 return result;
398
399 for (i = 0; i < length; i++) {
400 result = octeon_i2c_check_status(i2c, false);
401 if (result)
402 return result;
403
404 octeon_i2c_data_write(i2c, data[i]);
405 octeon_i2c_ctl_write(i2c, TWSI_CTL_ENAB);
406
407 result = octeon_i2c_wait(i2c);
408 if (result)
409 return result;
410 }
411
412 return 0;
413}
414
415/* high-level-controller pure read of up to 8 bytes */
416static int octeon_i2c_hlc_read(struct octeon_i2c *i2c, struct i2c_msg *msgs)
417{
418 int i, j, ret = 0;
419 u64 cmd;
420
421 octeon_i2c_hlc_enable(i2c);
422 octeon_i2c_hlc_int_clear(i2c);
423
424 cmd = SW_TWSI_V | SW_TWSI_R | SW_TWSI_SOVR;
425 /* SIZE */
426 cmd |= (u64)(msgs[0].len - 1) << SW_TWSI_SIZE_SHIFT;
427 /* A */
428 cmd |= (u64)(msgs[0].addr & 0x7full) << SW_TWSI_ADDR_SHIFT;
429
430 if (msgs[0].flags & I2C_M_TEN)
431 cmd |= SW_TWSI_OP_10;
432 else
433 cmd |= SW_TWSI_OP_7;
434
435 octeon_i2c_writeq_flush(cmd, i2c->twsi_base + OCTEON_REG_SW_TWSI(i2c));
436 ret = octeon_i2c_hlc_wait(i2c);
437 if (ret)
438 goto err;
439
440 cmd = __raw_readq(i2c->twsi_base + OCTEON_REG_SW_TWSI(i2c));
441 if ((cmd & SW_TWSI_R) == 0)
442 return octeon_i2c_check_status(i2c, false);
443
444 for (i = 0, j = msgs[0].len - 1; i < msgs[0].len && i < 4; i++, j--)
445 msgs[0].buf[j] = (cmd >> (8 * i)) & 0xff;
446
447 if (msgs[0].len > 4) {
448 cmd = __raw_readq(i2c->twsi_base + OCTEON_REG_SW_TWSI_EXT(i2c));
449 for (i = 0; i < msgs[0].len - 4 && i < 4; i++, j--)
450 msgs[0].buf[j] = (cmd >> (8 * i)) & 0xff;
451 }
452
453err:
454 return ret;
455}
456
457/* high-level-controller pure write of up to 8 bytes */
458static int octeon_i2c_hlc_write(struct octeon_i2c *i2c, struct i2c_msg *msgs)
459{
460 int i, j, ret = 0;
461 u64 cmd;
462
463 octeon_i2c_hlc_enable(i2c);
464 octeon_i2c_hlc_int_clear(i2c);
465
466 cmd = SW_TWSI_V | SW_TWSI_SOVR;
467 /* SIZE */
468 cmd |= (u64)(msgs[0].len - 1) << SW_TWSI_SIZE_SHIFT;
469 /* A */
470 cmd |= (u64)(msgs[0].addr & 0x7full) << SW_TWSI_ADDR_SHIFT;
471
472 if (msgs[0].flags & I2C_M_TEN)
473 cmd |= SW_TWSI_OP_10;
474 else
475 cmd |= SW_TWSI_OP_7;
476
477 for (i = 0, j = msgs[0].len - 1; i < msgs[0].len && i < 4; i++, j--)
478 cmd |= (u64)msgs[0].buf[j] << (8 * i);
479
480 if (msgs[0].len > 4) {
481 u64 ext = 0;
482
483 for (i = 0; i < msgs[0].len - 4 && i < 4; i++, j--)
484 ext |= (u64)msgs[0].buf[j] << (8 * i);
485 octeon_i2c_writeq_flush(ext, i2c->twsi_base + OCTEON_REG_SW_TWSI_EXT(i2c));
486 }
487
488 octeon_i2c_writeq_flush(cmd, i2c->twsi_base + OCTEON_REG_SW_TWSI(i2c));
489 ret = octeon_i2c_hlc_wait(i2c);
490 if (ret)
491 goto err;
492
493 cmd = __raw_readq(i2c->twsi_base + OCTEON_REG_SW_TWSI(i2c));
494 if ((cmd & SW_TWSI_R) == 0)
495 return octeon_i2c_check_status(i2c, false);
496
497err:
498 return ret;
499}
500
501/* high-level-controller composite write+read, msg0=addr, msg1=data */
502static int octeon_i2c_hlc_comp_read(struct octeon_i2c *i2c, struct i2c_msg *msgs)
503{
504 int i, j, ret = 0;
505 u64 cmd;
506
507 octeon_i2c_hlc_enable(i2c);
508
509 cmd = SW_TWSI_V | SW_TWSI_R | SW_TWSI_SOVR;
510 /* SIZE */
511 cmd |= (u64)(msgs[1].len - 1) << SW_TWSI_SIZE_SHIFT;
512 /* A */
513 cmd |= (u64)(msgs[0].addr & 0x7full) << SW_TWSI_ADDR_SHIFT;
514
515 if (msgs[0].flags & I2C_M_TEN)
516 cmd |= SW_TWSI_OP_10_IA;
517 else
518 cmd |= SW_TWSI_OP_7_IA;
519
520 if (msgs[0].len == 2) {
521 u64 ext = 0;
522
523 cmd |= SW_TWSI_EIA;
524 ext = (u64)msgs[0].buf[0] << SW_TWSI_IA_SHIFT;
525 cmd |= (u64)msgs[0].buf[1] << SW_TWSI_IA_SHIFT;
526 octeon_i2c_writeq_flush(ext, i2c->twsi_base + OCTEON_REG_SW_TWSI_EXT(i2c));
527 } else {
528 cmd |= (u64)msgs[0].buf[0] << SW_TWSI_IA_SHIFT;
529 }
530
531 octeon_i2c_hlc_int_clear(i2c);
532 octeon_i2c_writeq_flush(cmd, i2c->twsi_base + OCTEON_REG_SW_TWSI(i2c));
533
534 ret = octeon_i2c_hlc_wait(i2c);
535 if (ret)
536 goto err;
537
538 cmd = __raw_readq(i2c->twsi_base + OCTEON_REG_SW_TWSI(i2c));
539 if ((cmd & SW_TWSI_R) == 0)
540 return octeon_i2c_check_status(i2c, false);
541
542 for (i = 0, j = msgs[1].len - 1; i < msgs[1].len && i < 4; i++, j--)
543 msgs[1].buf[j] = (cmd >> (8 * i)) & 0xff;
544
545 if (msgs[1].len > 4) {
546 cmd = __raw_readq(i2c->twsi_base + OCTEON_REG_SW_TWSI_EXT(i2c));
547 for (i = 0; i < msgs[1].len - 4 && i < 4; i++, j--)
548 msgs[1].buf[j] = (cmd >> (8 * i)) & 0xff;
549 }
550
551err:
552 return ret;
553}
554
555/* high-level-controller composite write+write, m[0]len<=2, m[1]len<=8 */
556static int octeon_i2c_hlc_comp_write(struct octeon_i2c *i2c, struct i2c_msg *msgs)
557{
558 bool set_ext = false;
559 int i, j, ret = 0;
560 u64 cmd, ext = 0;
561
562 octeon_i2c_hlc_enable(i2c);
563
564 cmd = SW_TWSI_V | SW_TWSI_SOVR;
565 /* SIZE */
566 cmd |= (u64)(msgs[1].len - 1) << SW_TWSI_SIZE_SHIFT;
567 /* A */
568 cmd |= (u64)(msgs[0].addr & 0x7full) << SW_TWSI_ADDR_SHIFT;
569
570 if (msgs[0].flags & I2C_M_TEN)
571 cmd |= SW_TWSI_OP_10_IA;
572 else
573 cmd |= SW_TWSI_OP_7_IA;
574
575 if (msgs[0].len == 2) {
576 cmd |= SW_TWSI_EIA;
577 ext |= (u64)msgs[0].buf[0] << SW_TWSI_IA_SHIFT;
578 set_ext = true;
579 cmd |= (u64)msgs[0].buf[1] << SW_TWSI_IA_SHIFT;
580 } else {
581 cmd |= (u64)msgs[0].buf[0] << SW_TWSI_IA_SHIFT;
582 }
583
584 for (i = 0, j = msgs[1].len - 1; i < msgs[1].len && i < 4; i++, j--)
585 cmd |= (u64)msgs[1].buf[j] << (8 * i);
586
587 if (msgs[1].len > 4) {
588 for (i = 0; i < msgs[1].len - 4 && i < 4; i++, j--)
589 ext |= (u64)msgs[1].buf[j] << (8 * i);
590 set_ext = true;
591 }
592 if (set_ext)
593 octeon_i2c_writeq_flush(ext, i2c->twsi_base + OCTEON_REG_SW_TWSI_EXT(i2c));
594
595 octeon_i2c_hlc_int_clear(i2c);
596 octeon_i2c_writeq_flush(cmd, i2c->twsi_base + OCTEON_REG_SW_TWSI(i2c));
597
598 ret = octeon_i2c_hlc_wait(i2c);
599 if (ret)
600 goto err;
601
602 cmd = __raw_readq(i2c->twsi_base + OCTEON_REG_SW_TWSI(i2c));
603 if ((cmd & SW_TWSI_R) == 0)
604 return octeon_i2c_check_status(i2c, false);
605
606err:
607 return ret;
608}
609
610/**
611 * octeon_i2c_xfer - The driver's xfer function
612 * @adap: Pointer to the i2c_adapter structure
613 * @msgs: Pointer to the messages to be processed
614 * @num: Length of the MSGS array
615 *
616 * Returns the number of messages processed, or a negative errno on failure.
617 */
618int octeon_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
619{
620 struct octeon_i2c *i2c = i2c_get_adapdata(adap);
621 int i, ret = 0;
622
623 if (IS_LS_FREQ(i2c->twsi_freq)) {
624 if (num == 1) {
625 if (msgs[0].len > 0 && msgs[0].len <= 8) {
626 if (msgs[0].flags & I2C_M_RD)
627 ret = octeon_i2c_hlc_read(i2c, msgs);
628 else
629 ret = octeon_i2c_hlc_write(i2c, msgs);
630 goto out;
631 }
632 } else if (num == 2) {
633 if ((msgs[0].flags & I2C_M_RD) == 0 &&
634 (msgs[1].flags & I2C_M_RECV_LEN) == 0 &&
635 msgs[0].len > 0 && msgs[0].len <= 2 &&
636 msgs[1].len > 0 && msgs[1].len <= 8 &&
637 msgs[0].addr == msgs[1].addr) {
638 if (msgs[1].flags & I2C_M_RD)
639 ret = octeon_i2c_hlc_comp_read(i2c, msgs);
640 else
641 ret = octeon_i2c_hlc_comp_write(i2c, msgs);
642 goto out;
643 }
644 }
645 }
646
647 for (i = 0; ret == 0 && i < num; i++) {
648 struct i2c_msg *pmsg = &msgs[i];
649
650 /* zero-length messages are not supported */
651 if (!pmsg->len) {
652 ret = -EOPNOTSUPP;
653 break;
654 }
655
656 ret = octeon_i2c_start(i2c);
657 if (ret)
658 return ret;
659
660 if (pmsg->flags & I2C_M_RD)
661 ret = octeon_i2c_read(i2c, pmsg->addr, pmsg->buf,
662 &pmsg->len, pmsg->flags & I2C_M_RECV_LEN);
663 else
664 ret = octeon_i2c_write(i2c, pmsg->addr, pmsg->buf,
665 pmsg->len);
666 }
667 octeon_i2c_stop(i2c);
668out:
669 return (ret != 0) ? ret : num;
670}
671
672/* calculate and set clock divisors */
673void octeon_i2c_set_clock(struct octeon_i2c *i2c)
674{
675 int tclk, thp_base, inc, thp_idx, mdiv_idx, ndiv_idx, foscl, diff;
676 bool is_plat_otx2;
677 /*
678 * Find divisors to produce target frequency, start with large delta
679 * to cover wider range of divisors, note thp = TCLK half period and
680 * ds is OSCL output frequency divisor.
681 */
682 unsigned int thp, mdiv_min, mdiv = 2, ndiv = 0, ds = 10;
683 unsigned int delta_hz = INITIAL_DELTA_HZ;
684
685 is_plat_otx2 = octeon_i2c_is_otx2(to_pci_dev(i2c->dev));
686
687 if (is_plat_otx2) {
688 thp = TWSI_MASTER_CLK_REG_OTX2_VAL;
689 mdiv_min = 0;
690 if (!IS_LS_FREQ(i2c->twsi_freq))
691 ds = 15;
692 } else {
693 thp = TWSI_MASTER_CLK_REG_DEF_VAL;
694 mdiv_min = 2;
695 }
696
697 for (ndiv_idx = 0; ndiv_idx < 8 && delta_hz != 0; ndiv_idx++) {
698 /*
699 * An mdiv value of less than 2 seems to not work well
700 * with ds1337 RTCs, so we constrain it to larger values.
701 */
702 for (mdiv_idx = 15; mdiv_idx >= mdiv_min && delta_hz != 0; mdiv_idx--) {
703 /*
704 * For given ndiv and mdiv values check the
705 * two closest thp values.
706 */
707 tclk = i2c->twsi_freq * (mdiv_idx + 1) * ds;
708 tclk *= (1 << ndiv_idx);
709 if (is_plat_otx2)
710 thp_base = (i2c->sys_freq / tclk) - 2;
711 else
712 thp_base = (i2c->sys_freq / (tclk * 2)) - 1;
713
714 for (inc = 0; inc <= 1; inc++) {
715 thp_idx = thp_base + inc;
716 if (thp_idx < 5 || thp_idx > 0xff)
717 continue;
718
719 if (is_plat_otx2)
720 foscl = i2c->sys_freq / (thp_idx + 2);
721 else
722 foscl = i2c->sys_freq /
723 (2 * (thp_idx + 1));
724 foscl = foscl / (1 << ndiv_idx);
725 foscl = foscl / (mdiv_idx + 1) / ds;
726 if (foscl > i2c->twsi_freq)
727 continue;
728 diff = abs(foscl - i2c->twsi_freq);
729 /*
730 * Diff holds difference between calculated frequency
731 * value vs desired frequency.
732 * Delta_hz is updated with last minimum diff.
733 */
734 if (diff < delta_hz) {
735 delta_hz = diff;
736 thp = thp_idx;
737 mdiv = mdiv_idx;
738 ndiv = ndiv_idx;
739 }
740 }
741 }
742 }
743 octeon_i2c_reg_write(i2c, SW_TWSI_OP_TWSI_CLK, thp);
744 octeon_i2c_reg_write(i2c, SW_TWSI_EOP_TWSI_CLKCTL, (mdiv << 3) | ndiv);
745 if (is_plat_otx2) {
746 u64 mode;
747
748 mode = __raw_readq(i2c->twsi_base + OCTEON_REG_MODE(i2c));
749 /* Set REFCLK_SRC and HS_MODE in TWSX_MODE register */
750 if (!IS_LS_FREQ(i2c->twsi_freq))
751 mode |= TWSX_MODE_HS_MASK;
752 else
753 mode &= ~TWSX_MODE_HS_MASK;
754 octeon_i2c_writeq_flush(mode, i2c->twsi_base + OCTEON_REG_MODE(i2c));
755 }
756}
757
758int octeon_i2c_init_lowlevel(struct octeon_i2c *i2c)
759{
760 u8 status = 0;
761 int tries;
762
763 /* reset controller */
764 octeon_i2c_reg_write(i2c, SW_TWSI_EOP_TWSI_RST, 0);
765
766 for (tries = 10; tries && status != STAT_IDLE; tries--) {
767 udelay(1);
768 status = octeon_i2c_stat_read(i2c);
769 if (status == STAT_IDLE)
770 break;
771 }
772
773 if (status != STAT_IDLE) {
774 dev_err(i2c->dev, "%s: TWSI_RST failed! (0x%x)\n",
775 __func__, status);
776 return -EIO;
777 }
778
779 /* toggle twice to force both teardowns */
780 octeon_i2c_hlc_enable(i2c);
781 octeon_i2c_hlc_disable(i2c);
782 return 0;
783}
784
785static int octeon_i2c_get_scl(struct i2c_adapter *adap)
786{
787 struct octeon_i2c *i2c = i2c_get_adapdata(adap);
788 u64 state;
789
790 state = octeon_i2c_read_int(i2c);
791 return state & TWSI_INT_SCL;
792}
793
794static void octeon_i2c_set_scl(struct i2c_adapter *adap, int val)
795{
796 struct octeon_i2c *i2c = i2c_get_adapdata(adap);
797
798 octeon_i2c_write_int(i2c, val ? 0 : TWSI_INT_SCL_OVR);
799}
800
801static int octeon_i2c_get_sda(struct i2c_adapter *adap)
802{
803 struct octeon_i2c *i2c = i2c_get_adapdata(adap);
804 u64 state;
805
806 state = octeon_i2c_read_int(i2c);
807 return state & TWSI_INT_SDA;
808}
809
810static void octeon_i2c_prepare_recovery(struct i2c_adapter *adap)
811{
812 struct octeon_i2c *i2c = i2c_get_adapdata(adap);
813
814 octeon_i2c_hlc_disable(i2c);
815 octeon_i2c_reg_write(i2c, SW_TWSI_EOP_TWSI_RST, 0);
816 /* wait for software reset to settle */
817 udelay(5);
818
819 /*
820 * Bring control register to a good state regardless
821 * of HLC state.
822 */
823 octeon_i2c_ctl_write(i2c, TWSI_CTL_ENAB);
824
825 octeon_i2c_write_int(i2c, 0);
826}
827
828static void octeon_i2c_unprepare_recovery(struct i2c_adapter *adap)
829{
830 struct octeon_i2c *i2c = i2c_get_adapdata(adap);
831
832 /*
833 * Generate STOP to finish the unfinished transaction.
834 * Can't generate STOP via the TWSI CTL register
835 * since it could bring the TWSI controller into an inoperable state.
836 */
837 octeon_i2c_write_int(i2c, TWSI_INT_SDA_OVR | TWSI_INT_SCL_OVR);
838 udelay(5);
839 octeon_i2c_write_int(i2c, TWSI_INT_SDA_OVR);
840 udelay(5);
841 octeon_i2c_write_int(i2c, 0);
842}
843
844struct i2c_bus_recovery_info octeon_i2c_recovery_info = {
845 .recover_bus = i2c_generic_scl_recovery,
846 .get_scl = octeon_i2c_get_scl,
847 .set_scl = octeon_i2c_set_scl,
848 .get_sda = octeon_i2c_get_sda,
849 .prepare_recovery = octeon_i2c_prepare_recovery,
850 .unprepare_recovery = octeon_i2c_unprepare_recovery,
851};