1/*-
2 * Copyright (C) 2008 MARVELL INTERNATIONAL LTD.
3 * All rights reserved.
4 *
5 * Developed by Semihalf.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 * 3. Neither the name of MARVELL nor the names of contributors
16 * may be used to endorse or promote products derived from this software
17 * without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY AUTHOR AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED. IN NO EVENT SHALL AUTHOR OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 */
31
32/*
33 * Driver for the TWSI (aka I2C, aka IIC) bus controller found on Marvell
34 * SoCs. Supports master operation only, and works in polling mode.
35 *
36 * Calls to DELAY() are needed per Application Note AN-179 "TWSI Software
37 * Guidelines for Discovery(TM), Horizon (TM) and Feroceon(TM) Devices".
38 */
39
40#include <sys/cdefs.h>
|
41__FBSDID("$FreeBSD: stable/10/sys/arm/mv/twsi.c 239508 2012-08-21 17:49:20Z hrs $");
|
| 41__FBSDID("$FreeBSD: stable/10/sys/arm/mv/twsi.c 266152 2014-05-15 16:11:06Z ian $"); |
42
43#include <sys/param.h>
44#include <sys/systm.h>
45#include <sys/bus.h>
46#include <sys/kernel.h>
47#include <sys/module.h>
48#include <sys/resource.h>
49
50#include <machine/_inttypes.h>
51#include <machine/bus.h>
52#include <machine/resource.h>
53
54#include <sys/rman.h>
55
56#include <sys/lock.h>
57#include <sys/mutex.h>
58
59#include <dev/iicbus/iiconf.h>
60#include <dev/iicbus/iicbus.h>
61#include <dev/fdt/fdt_common.h>
62#include <dev/ofw/ofw_bus.h>
63#include <dev/ofw/ofw_bus_subr.h>
64
65#include <arm/mv/mvreg.h>
66#include <arm/mv/mvvar.h>
67
68#include "iicbus_if.h"
69
70#define MV_TWSI_NAME "twsi"
71#define IICBUS_DEVNAME "iicbus"
72
73#define TWSI_SLAVE_ADDR 0x00
74#define TWSI_EXT_SLAVE_ADDR 0x10
75#define TWSI_DATA 0x04
76
77#define TWSI_CONTROL 0x08
78#define TWSI_CONTROL_ACK (1 << 2)
79#define TWSI_CONTROL_IFLG (1 << 3)
80#define TWSI_CONTROL_STOP (1 << 4)
81#define TWSI_CONTROL_START (1 << 5)
82#define TWSI_CONTROL_TWSIEN (1 << 6)
83#define TWSI_CONTROL_INTEN (1 << 7)
84
85#define TWSI_STATUS 0x0c
86#define TWSI_STATUS_START 0x08
87#define TWSI_STATUS_RPTD_START 0x10
88#define TWSI_STATUS_ADDR_W_ACK 0x18
89#define TWSI_STATUS_DATA_WR_ACK 0x28
90#define TWSI_STATUS_ADDR_R_ACK 0x40
91#define TWSI_STATUS_DATA_RD_ACK 0x50
92#define TWSI_STATUS_DATA_RD_NOACK 0x58
93
94#define TWSI_BAUD_RATE 0x0c
95#define TWSI_BAUD_RATE_PARAM(M,N) ((((M) << 3) | ((N) & 0x7)) & 0x7f)
96#define TWSI_BAUD_RATE_RAW(C,M,N) ((C)/((10*(M+1))<<(N+1)))
97#define TWSI_BAUD_RATE_SLOW 50000 /* 50kHz */
98#define TWSI_BAUD_RATE_FAST 100000 /* 100kHz */
99
100#define TWSI_SOFT_RESET 0x1c
101
102#define TWSI_DEBUG
103#undef TWSI_DEBUG
104
105#ifdef TWSI_DEBUG
106#define debugf(fmt, args...) do { printf("%s(): ", __func__); printf(fmt,##args); } while (0)
107#else
108#define debugf(fmt, args...)
109#endif
110
111struct mv_twsi_softc {
112 device_t dev;
113 struct resource *res[1]; /* SYS_RES_MEMORY */
114 struct mtx mutex;
115 device_t iicbus;
116};
117
118static struct mv_twsi_baud_rate {
119 uint32_t raw;
120 int param;
121 int m;
122 int n;
123} baud_rate[IIC_FASTEST + 1];
124
125static int mv_twsi_probe(device_t);
126static int mv_twsi_attach(device_t);
127static int mv_twsi_detach(device_t);
128
129static int mv_twsi_reset(device_t dev, u_char speed, u_char addr,
130 u_char *oldaddr);
131static int mv_twsi_repeated_start(device_t dev, u_char slave, int timeout);
132static int mv_twsi_start(device_t dev, u_char slave, int timeout);
133static int mv_twsi_stop(device_t dev);
134static int mv_twsi_read(device_t dev, char *buf, int len, int *read, int last,
135 int delay);
136static int mv_twsi_write(device_t dev, const char *buf, int len, int *sent,
137 int timeout);
138
139static struct resource_spec res_spec[] = {
140 { SYS_RES_MEMORY, 0, RF_ACTIVE },
141 { -1, 0 }
142};
143
144static device_method_t mv_twsi_methods[] = {
145 /* device interface */
146 DEVMETHOD(device_probe, mv_twsi_probe),
147 DEVMETHOD(device_attach, mv_twsi_attach),
148 DEVMETHOD(device_detach, mv_twsi_detach),
149
150 /* iicbus interface */
151 DEVMETHOD(iicbus_callback, iicbus_null_callback),
152 DEVMETHOD(iicbus_repeated_start, mv_twsi_repeated_start),
153 DEVMETHOD(iicbus_start, mv_twsi_start),
154 DEVMETHOD(iicbus_stop, mv_twsi_stop),
155 DEVMETHOD(iicbus_write, mv_twsi_write),
156 DEVMETHOD(iicbus_read, mv_twsi_read),
157 DEVMETHOD(iicbus_reset, mv_twsi_reset),
158 DEVMETHOD(iicbus_transfer, iicbus_transfer_gen),
159 { 0, 0 }
160};
161
162static devclass_t mv_twsi_devclass;
163
164static driver_t mv_twsi_driver = {
165 MV_TWSI_NAME,
166 mv_twsi_methods,
167 sizeof(struct mv_twsi_softc),
168};
169
170DRIVER_MODULE(twsi, simplebus, mv_twsi_driver, mv_twsi_devclass, 0, 0);
171DRIVER_MODULE(iicbus, twsi, iicbus_driver, iicbus_devclass, 0, 0);
172MODULE_DEPEND(twsi, iicbus, 1, 1, 1);
173
174static __inline uint32_t
175TWSI_READ(struct mv_twsi_softc *sc, bus_size_t off)
176{
177
178 return (bus_read_4(sc->res[0], off));
179}
180
181static __inline void
182TWSI_WRITE(struct mv_twsi_softc *sc, bus_size_t off, uint32_t val)
183{
184
185 bus_write_4(sc->res[0], off, val);
186}
187
188static __inline void
189twsi_control_clear(struct mv_twsi_softc *sc, uint32_t mask)
190{
191 uint32_t val;
192
193 val = TWSI_READ(sc, TWSI_CONTROL);
194 val &= ~mask;
195 TWSI_WRITE(sc, TWSI_CONTROL, val);
196}
197
198static __inline void
199twsi_control_set(struct mv_twsi_softc *sc, uint32_t mask)
200{
201 uint32_t val;
202
203 val = TWSI_READ(sc, TWSI_CONTROL);
204 val |= mask;
205 TWSI_WRITE(sc, TWSI_CONTROL, val);
206}
207
208static __inline void
209twsi_clear_iflg(struct mv_twsi_softc *sc)
210{
211
212 DELAY(1000);
213 twsi_control_clear(sc, TWSI_CONTROL_IFLG);
214 DELAY(1000);
215}
216
217
218/*
219 * timeout given in us
220 * returns
221 * 0 on sucessfull mask change
222 * non-zero on timeout
223 */
224static int
225twsi_poll_ctrl(struct mv_twsi_softc *sc, int timeout, uint32_t mask)
226{
227
228 timeout /= 10;
229 while (!(TWSI_READ(sc, TWSI_CONTROL) & mask)) {
230 DELAY(10);
231 if (--timeout < 0)
232 return (timeout);
233 }
234 return (0);
235}
236
237
238/*
239 * 'timeout' is given in us. Note also that timeout handling is not exact --
240 * twsi_locked_start() total wait can be more than 2 x timeout
241 * (twsi_poll_ctrl() is called twice). 'mask' can be either TWSI_STATUS_START
242 * or TWSI_STATUS_RPTD_START
243 */
244static int
245twsi_locked_start(device_t dev, struct mv_twsi_softc *sc, int32_t mask,
246 u_char slave, int timeout)
247{
248 int read_access, iflg_set = 0;
249 uint32_t status;
250
251 mtx_assert(&sc->mutex, MA_OWNED);
252
253 if (mask == TWSI_STATUS_RPTD_START)
254 /* read IFLG to know if it should be cleared later; from NBSD */
255 iflg_set = TWSI_READ(sc, TWSI_CONTROL) & TWSI_CONTROL_IFLG;
256
257 twsi_control_set(sc, TWSI_CONTROL_START);
258
259 if (mask == TWSI_STATUS_RPTD_START && iflg_set) {
260 debugf("IFLG set, clearing\n");
261 twsi_clear_iflg(sc);
262 }
263
264 /*
265 * Without this delay we timeout checking IFLG if the timeout is 0.
266 * NBSD driver always waits here too.
267 */
268 DELAY(1000);
269
270 if (twsi_poll_ctrl(sc, timeout, TWSI_CONTROL_IFLG)) {
271 debugf("timeout sending %sSTART condition\n",
272 mask == TWSI_STATUS_START ? "" : "repeated ");
273 return (IIC_ETIMEOUT);
274 }
275
276 status = TWSI_READ(sc, TWSI_STATUS);
277 if (status != mask) {
278 debugf("wrong status (%02x) after sending %sSTART condition\n",
279 status, mask == TWSI_STATUS_START ? "" : "repeated ");
280 return (IIC_ESTATUS);
281 }
282
283 TWSI_WRITE(sc, TWSI_DATA, slave);
284 DELAY(1000);
285 twsi_clear_iflg(sc);
286
287 if (twsi_poll_ctrl(sc, timeout, TWSI_CONTROL_IFLG)) {
288 debugf("timeout sending slave address\n");
289 return (IIC_ETIMEOUT);
290 }
291
292 read_access = (slave & 0x1) ? 1 : 0;
293 status = TWSI_READ(sc, TWSI_STATUS);
294 if (status != (read_access ?
295 TWSI_STATUS_ADDR_R_ACK : TWSI_STATUS_ADDR_W_ACK)) {
296 debugf("no ACK (status: %02x) after sending slave address\n",
297 status);
298 return (IIC_ENOACK);
299 }
300
301 return (IIC_NOERR);
302}
303
304static int
305mv_twsi_probe(device_t dev)
306{
307
|
308 if (!ofw_bus_status_okay(dev))
309 return (ENXIO);
310 |
311 if (!ofw_bus_is_compatible(dev, "mrvl,twsi"))
312 return (ENXIO);
313
314 device_set_desc(dev, "Marvell Integrated I2C Bus Controller");
315 return (BUS_PROBE_DEFAULT);
316}
317
318#define ABSSUB(a,b) (((a) > (b)) ? (a) - (b) : (b) - (a))
319static void
320mv_twsi_cal_baud_rate(const uint32_t target, struct mv_twsi_baud_rate *rate)
321{
322 uint32_t clk, cur, diff, diff0;
323 int m, n, m0, n0;
324
325 /* Calculate baud rate. */
326 m0 = n0 = 4; /* Default values on reset */
327 diff0 = 0xffffffff;
328 clk = get_tclk();
329
330 for (n = 0; n < 8; n++) {
331 for (m = 0; m < 16; m++) {
332 cur = TWSI_BAUD_RATE_RAW(clk,m,n);
333 diff = ABSSUB(target, cur);
334 if (diff < diff0) {
335 m0 = m;
336 n0 = n;
337 diff0 = diff;
338 }
339 }
340 }
341 rate->raw = TWSI_BAUD_RATE_RAW(clk, m0, n0);
342 rate->param = TWSI_BAUD_RATE_PARAM(m0, n0);
343 rate->m = m0;
344 rate->n = n0;
345}
346
347static int
348mv_twsi_attach(device_t dev)
349{
350 struct mv_twsi_softc *sc;
351 phandle_t child, iicbusnode;
352 device_t childdev;
353 struct iicbus_ivar *devi;
354 char dname[32]; /* 32 is taken from struct u_device */
355 uint32_t paddr;
356 int len, error;
357
358 sc = device_get_softc(dev);
359 sc->dev = dev;
360 bzero(baud_rate, sizeof(baud_rate));
361
362 mtx_init(&sc->mutex, device_get_nameunit(dev), MV_TWSI_NAME, MTX_DEF);
363
364 /* Allocate IO resources */
365 if (bus_alloc_resources(dev, res_spec, sc->res)) {
366 device_printf(dev, "could not allocate resources\n");
367 mv_twsi_detach(dev);
368 return (ENXIO);
369 }
370
371 mv_twsi_cal_baud_rate(TWSI_BAUD_RATE_SLOW, &baud_rate[IIC_SLOW]);
372 mv_twsi_cal_baud_rate(TWSI_BAUD_RATE_FAST, &baud_rate[IIC_FAST]);
373 if (bootverbose)
374 device_printf(dev, "calculated baud rates are:\n"
375 " %" PRIu32 " kHz (M=%d, N=%d) for slow,\n"
376 " %" PRIu32 " kHz (M=%d, N=%d) for fast.\n",
377 baud_rate[IIC_SLOW].raw / 1000,
378 baud_rate[IIC_SLOW].m,
379 baud_rate[IIC_SLOW].n,
380 baud_rate[IIC_FAST].raw / 1000,
381 baud_rate[IIC_FAST].m,
382 baud_rate[IIC_FAST].n);
383
384 sc->iicbus = device_add_child(dev, IICBUS_DEVNAME, -1);
385 if (sc->iicbus == NULL) {
386 device_printf(dev, "could not add iicbus child\n");
387 mv_twsi_detach(dev);
388 return (ENXIO);
389 }
390 /* Attach iicbus. */
391 bus_generic_attach(dev);
392
393 iicbusnode = 0;
394 /* Find iicbus as the child devices in the device tree. */
395 for (child = OF_child(ofw_bus_get_node(dev)); child != 0;
396 child = OF_peer(child)) {
397 len = OF_getproplen(child, "model");
398 if (len <= 0 || len > sizeof(dname) - 1)
399 continue;
400 error = OF_getprop(child, "model", &dname, len);
401 dname[len + 1] = '\0';
402 if (error == -1)
403 continue;
404 len = strlen(dname);
405 if (len == strlen(IICBUS_DEVNAME) &&
406 strncasecmp(dname, IICBUS_DEVNAME, len) == 0) {
407 iicbusnode = child;
408 break;
409 }
410 }
411 if (iicbusnode == 0)
412 goto attach_end;
413
414 /* Attach child devices onto iicbus. */
415 for (child = OF_child(iicbusnode); child != 0; child = OF_peer(child)) {
416 /* Get slave address. */
417 error = OF_getprop(child, "i2c-address", &paddr, sizeof(paddr));
418 if (error == -1)
419 error = OF_getprop(child, "reg", &paddr, sizeof(paddr));
420 if (error == -1)
421 continue;
422
423 /* Get device driver name. */
424 len = OF_getproplen(child, "model");
425 if (len <= 0 || len > sizeof(dname) - 1)
426 continue;
427 OF_getprop(child, "model", &dname, len);
428 dname[len + 1] = '\0';
429
430 if (bootverbose)
431 device_printf(dev, "adding a device %s at %d.\n",
432 dname, fdt32_to_cpu(paddr));
433 childdev = BUS_ADD_CHILD(sc->iicbus, 0, dname, -1);
434 devi = IICBUS_IVAR(childdev);
435 devi->addr = fdt32_to_cpu(paddr);
436 }
437
438attach_end:
439 bus_generic_attach(sc->iicbus);
440
441 return (0);
442}
443
444static int
445mv_twsi_detach(device_t dev)
446{
447 struct mv_twsi_softc *sc;
448 int rv;
449
450 sc = device_get_softc(dev);
451
452 if ((rv = bus_generic_detach(dev)) != 0)
453 return (rv);
454
455 if (sc->iicbus != NULL)
456 if ((rv = device_delete_child(dev, sc->iicbus)) != 0)
457 return (rv);
458
459 bus_release_resources(dev, res_spec, sc->res);
460
461 mtx_destroy(&sc->mutex);
462 return (0);
463}
464
465/*
466 * Only slave mode supported, disregard [old]addr
467 */
468static int
469mv_twsi_reset(device_t dev, u_char speed, u_char addr, u_char *oldaddr)
470{
471 struct mv_twsi_softc *sc;
472 uint32_t param;
473
474 sc = device_get_softc(dev);
475
476 switch (speed) {
477 case IIC_SLOW:
478 case IIC_FAST:
479 param = baud_rate[speed].param;
480 break;
481 case IIC_FASTEST:
482 case IIC_UNKNOWN:
483 default:
484 param = baud_rate[IIC_FAST].param;
485 break;
486 }
487
488 mtx_lock(&sc->mutex);
489 TWSI_WRITE(sc, TWSI_SOFT_RESET, 0x0);
490 DELAY(2000);
491 TWSI_WRITE(sc, TWSI_BAUD_RATE, param);
492 TWSI_WRITE(sc, TWSI_CONTROL, TWSI_CONTROL_TWSIEN | TWSI_CONTROL_ACK);
493 DELAY(1000);
494 mtx_unlock(&sc->mutex);
495
496 return (0);
497}
498
499/*
500 * timeout is given in us
501 */
502static int
503mv_twsi_repeated_start(device_t dev, u_char slave, int timeout)
504{
505 struct mv_twsi_softc *sc;
506 int rv;
507
508 sc = device_get_softc(dev);
509
510 mtx_lock(&sc->mutex);
511 rv = twsi_locked_start(dev, sc, TWSI_STATUS_RPTD_START, slave,
512 timeout);
513 mtx_unlock(&sc->mutex);
514
515 if (rv) {
516 mv_twsi_stop(dev);
517 return (rv);
518 } else
519 return (IIC_NOERR);
520}
521
522/*
523 * timeout is given in us
524 */
525static int
526mv_twsi_start(device_t dev, u_char slave, int timeout)
527{
528 struct mv_twsi_softc *sc;
529 int rv;
530
531 sc = device_get_softc(dev);
532
533 mtx_lock(&sc->mutex);
534 rv = twsi_locked_start(dev, sc, TWSI_STATUS_START, slave, timeout);
535 mtx_unlock(&sc->mutex);
536
537 if (rv) {
538 mv_twsi_stop(dev);
539 return (rv);
540 } else
541 return (IIC_NOERR);
542}
543
544static int
545mv_twsi_stop(device_t dev)
546{
547 struct mv_twsi_softc *sc;
548
549 sc = device_get_softc(dev);
550
551 mtx_lock(&sc->mutex);
552 twsi_control_set(sc, TWSI_CONTROL_STOP);
553 DELAY(1000);
554 twsi_clear_iflg(sc);
555 mtx_unlock(&sc->mutex);
556
557 return (IIC_NOERR);
558}
559
560static int
561mv_twsi_read(device_t dev, char *buf, int len, int *read, int last, int delay)
562{
563 struct mv_twsi_softc *sc;
564 uint32_t status;
565 int last_byte, rv;
566
567 sc = device_get_softc(dev);
568
569 mtx_lock(&sc->mutex);
570 *read = 0;
571 while (*read < len) {
572 /*
573 * Check if we are reading last byte of the last buffer,
574 * do not send ACK then, per I2C specs
575 */
576 last_byte = ((*read == len - 1) && last) ? 1 : 0;
577 if (last_byte)
578 twsi_control_clear(sc, TWSI_CONTROL_ACK);
579 else
580 twsi_control_set(sc, TWSI_CONTROL_ACK);
581
582 DELAY (1000);
583 twsi_clear_iflg(sc);
584
585 if (twsi_poll_ctrl(sc, delay, TWSI_CONTROL_IFLG)) {
586 debugf("timeout reading data\n");
587 rv = IIC_ETIMEOUT;
588 goto out;
589 }
590
591 status = TWSI_READ(sc, TWSI_STATUS);
592 if (status != (last_byte ?
593 TWSI_STATUS_DATA_RD_NOACK : TWSI_STATUS_DATA_RD_ACK)) {
594 debugf("wrong status (%02x) while reading\n", status);
595 rv = IIC_ESTATUS;
596 goto out;
597 }
598
599 *buf++ = TWSI_READ(sc, TWSI_DATA);
600 (*read)++;
601 }
602 rv = IIC_NOERR;
603out:
604 mtx_unlock(&sc->mutex);
605 return (rv);
606}
607
608static int
609mv_twsi_write(device_t dev, const char *buf, int len, int *sent, int timeout)
610{
611 struct mv_twsi_softc *sc;
612 uint32_t status;
613 int rv;
614
615 sc = device_get_softc(dev);
616
617 mtx_lock(&sc->mutex);
618 *sent = 0;
619 while (*sent < len) {
620 TWSI_WRITE(sc, TWSI_DATA, *buf++);
621
622 twsi_clear_iflg(sc);
623 if (twsi_poll_ctrl(sc, timeout, TWSI_CONTROL_IFLG)) {
624 debugf("timeout writing data\n");
625 rv = IIC_ETIMEOUT;
626 goto out;
627 }
628
629 status = TWSI_READ(sc, TWSI_STATUS);
630 if (status != TWSI_STATUS_DATA_WR_ACK) {
631 debugf("wrong status (%02x) while writing\n", status);
632 rv = IIC_ESTATUS;
633 goto out;
634 }
635 (*sent)++;
636 }
637 rv = IIC_NOERR;
638out:
639 mtx_unlock(&sc->mutex);
640 return (rv);
641}
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