1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause
3 *
4 * Copyright (c) 1998 Nicolas Souchu
5 * All rights reserved.
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 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28
29 #include <sys/cdefs.h>
30 #include <sys/param.h>
31 #include <sys/systm.h>
32 #include <sys/lock.h>
33 #include <sys/malloc.h>
34 #include <sys/module.h>
35 #include <sys/mutex.h>
36 #include <sys/bus.h>
37
38 #include <dev/iicbus/iiconf.h>
39 #include <dev/iicbus/iicbus.h>
40 #include "iicbus_if.h"
41
42 /*
43 * Encode a system errno value into the IIC_Exxxxx space by setting the
44 * IIC_ERRNO marker bit, so that iic2errno() can turn it back into a plain
45 * system errno value later. This lets controller- and bus-layer code get
46 * important system errno values (such as EINTR/ERESTART) back to the caller.
47 */
48 int
errno2iic(int errno)49 errno2iic(int errno)
50 {
51 return ((errno == 0) ? 0 : errno | IIC_ERRNO);
52 }
53
54 /*
55 * Translate IIC_Exxxxx status values to vaguely-equivelent errno values.
56 */
57 int
iic2errno(int iic_status)58 iic2errno(int iic_status)
59 {
60 switch (iic_status) {
61 case IIC_NOERR: return (0);
62 case IIC_EBUSERR: return (EALREADY);
63 case IIC_ENOACK: return (EIO);
64 case IIC_ETIMEOUT: return (ETIMEDOUT);
65 case IIC_EBUSBSY: return (EWOULDBLOCK);
66 case IIC_ESTATUS: return (EPROTO);
67 case IIC_EUNDERFLOW: return (EIO);
68 case IIC_EOVERFLOW: return (EOVERFLOW);
69 case IIC_ENOTSUPP: return (EOPNOTSUPP);
70 case IIC_ENOADDR: return (EADDRNOTAVAIL);
71 case IIC_ERESOURCE: return (ENOMEM);
72 default:
73 /*
74 * If the high bit is set, that means it's a system errno value
75 * that was encoded into the IIC_Exxxxxx space by setting the
76 * IIC_ERRNO marker bit. If lots of high-order bits are set,
77 * then it's one of the negative pseudo-errors such as ERESTART
78 * and we return it as-is. Otherwise it's a plain "small
79 * positive integer" errno, so just remove the IIC_ERRNO marker
80 * bit. If it's some unknown number without the high bit set,
81 * there isn't much we can do except call it an I/O error.
82 */
83 if ((iic_status & IIC_ERRNO) == 0)
84 return (EIO);
85 if ((iic_status & 0xFFFF0000) != 0)
86 return (iic_status);
87 return (iic_status & ~IIC_ERRNO);
88 }
89 }
90
91 /*
92 * iicbus_intr()
93 */
94 void
iicbus_intr(device_t bus,int event,char * buf)95 iicbus_intr(device_t bus, int event, char *buf)
96 {
97 struct iicbus_softc *sc = (struct iicbus_softc *)device_get_softc(bus);
98
99 /* call owner's intr routine */
100 if (sc->owner)
101 IICBUS_INTR(sc->owner, event, buf);
102
103 return;
104 }
105
106 static int
iicbus_poll(struct iicbus_softc * sc,int how)107 iicbus_poll(struct iicbus_softc *sc, int how)
108 {
109 int error;
110
111 IICBUS_ASSERT_LOCKED(sc);
112 switch (how & IIC_INTRWAIT) {
113 case IIC_WAIT | IIC_INTR:
114 error = mtx_sleep(sc, &sc->lock, IICPRI|PCATCH, "iicreq", 0);
115 break;
116
117 case IIC_WAIT | IIC_NOINTR:
118 error = mtx_sleep(sc, &sc->lock, IICPRI, "iicreq", 0);
119 break;
120
121 default:
122 return (IIC_EBUSBSY);
123 }
124
125 return (errno2iic(error));
126 }
127
128 /*
129 * iicbus_request_bus()
130 *
131 * Allocate the device to perform transfers.
132 *
133 * how : IIC_WAIT or IIC_DONTWAIT
134 */
135 int
iicbus_request_bus(device_t bus,device_t dev,int how)136 iicbus_request_bus(device_t bus, device_t dev, int how)
137 {
138 struct iic_reqbus_data reqdata;
139 struct iicbus_softc *sc = (struct iicbus_softc *)device_get_softc(bus);
140 int error = 0;
141
142 IICBUS_LOCK(sc);
143
144 for (;;) {
145 if (sc->owner == NULL)
146 break;
147 if ((how & IIC_RECURSIVE) && sc->owner == dev)
148 break;
149 if ((error = iicbus_poll(sc, how)) != 0)
150 break;
151 }
152
153 if (error == 0) {
154 ++sc->owncount;
155 if (sc->owner == NULL) {
156 sc->owner = dev;
157 /*
158 * Mark the device busy while it owns the bus, to
159 * prevent detaching the device, bus, or hardware
160 * controller, until ownership is relinquished. If the
161 * device is doing IO from its probe method before
162 * attaching, it cannot be busied; mark the bus busy.
163 */
164 if (device_get_state(dev) < DS_ATTACHING)
165 sc->busydev = bus;
166 else
167 sc->busydev = dev;
168 device_busy(sc->busydev);
169 /*
170 * Drop the lock around the call to the bus driver, it
171 * should be allowed to sleep in the IIC_WAIT case.
172 * Drivers might also need to grab locks that would
173 * cause a LOR if our lock is held.
174 */
175 IICBUS_UNLOCK(sc);
176 /* Ask the underlying layers if the request is ok */
177 reqdata.dev = dev;
178 reqdata.bus = bus;
179 reqdata.flags = how | IIC_REQBUS_DEV;
180 error = IICBUS_CALLBACK(device_get_parent(bus),
181 IIC_REQUEST_BUS, (caddr_t)&reqdata);
182 IICBUS_LOCK(sc);
183
184 if (error != 0) {
185 sc->owner = NULL;
186 sc->owncount = 0;
187 wakeup_one(sc);
188 device_unbusy(sc->busydev);
189 }
190 }
191 }
192
193 IICBUS_UNLOCK(sc);
194
195 return (error);
196 }
197
198 /*
199 * iicbus_release_bus()
200 *
201 * Release the device allocated with iicbus_request_dev()
202 */
203 int
iicbus_release_bus(device_t bus,device_t dev)204 iicbus_release_bus(device_t bus, device_t dev)
205 {
206 struct iic_reqbus_data reqdata;
207 struct iicbus_softc *sc = (struct iicbus_softc *)device_get_softc(bus);
208
209 IICBUS_LOCK(sc);
210
211 if (sc->owner != dev) {
212 IICBUS_UNLOCK(sc);
213 return (IIC_EBUSBSY);
214 }
215
216 if (--sc->owncount == 0) {
217 /* Drop the lock while informing the low-level driver. */
218 IICBUS_UNLOCK(sc);
219 reqdata.dev = dev;
220 reqdata.bus = bus;
221 reqdata.flags = IIC_REQBUS_DEV;
222 IICBUS_CALLBACK(device_get_parent(bus), IIC_RELEASE_BUS,
223 (caddr_t)&reqdata);
224 IICBUS_LOCK(sc);
225 sc->owner = NULL;
226 wakeup_one(sc);
227 device_unbusy(sc->busydev);
228 }
229 IICBUS_UNLOCK(sc);
230 return (0);
231 }
232
233 /*
234 * iicbus_started()
235 *
236 * Test if the iicbus is started by the controller
237 */
238 int
iicbus_started(device_t bus)239 iicbus_started(device_t bus)
240 {
241 struct iicbus_softc *sc = (struct iicbus_softc *)device_get_softc(bus);
242
243 return (sc->started);
244 }
245
246 /*
247 * iicbus_start()
248 *
249 * Send start condition to the slave addressed by 'slave'
250 */
251 int
iicbus_start(device_t bus,u_char slave,int timeout)252 iicbus_start(device_t bus, u_char slave, int timeout)
253 {
254 struct iicbus_softc *sc = (struct iicbus_softc *)device_get_softc(bus);
255 int error = 0;
256
257 if (sc->started)
258 return (IIC_ESTATUS); /* protocol error, bus already started */
259
260 if (!(error = IICBUS_START(device_get_parent(bus), slave, timeout)))
261 sc->started = slave;
262 else
263 sc->started = 0;
264
265 return (error);
266 }
267
268 /*
269 * iicbus_repeated_start()
270 *
271 * Send start condition to the slave addressed by 'slave'
272 */
273 int
iicbus_repeated_start(device_t bus,u_char slave,int timeout)274 iicbus_repeated_start(device_t bus, u_char slave, int timeout)
275 {
276 struct iicbus_softc *sc = (struct iicbus_softc *)device_get_softc(bus);
277 int error = 0;
278
279 if (!sc->started)
280 return (IIC_ESTATUS); /* protocol error, bus not started */
281
282 if (!(error = IICBUS_REPEATED_START(device_get_parent(bus), slave, timeout)))
283 sc->started = slave;
284 else
285 sc->started = 0;
286
287 return (error);
288 }
289
290 /*
291 * iicbus_stop()
292 *
293 * Send stop condition to the bus
294 */
295 int
iicbus_stop(device_t bus)296 iicbus_stop(device_t bus)
297 {
298 struct iicbus_softc *sc = (struct iicbus_softc *)device_get_softc(bus);
299 int error = 0;
300
301 if (!sc->started)
302 return (IIC_ESTATUS); /* protocol error, bus not started */
303
304 error = IICBUS_STOP(device_get_parent(bus));
305
306 /* refuse any further access */
307 sc->started = 0;
308
309 return (error);
310 }
311
312 /*
313 * iicbus_write()
314 *
315 * Write a block of data to the slave previously started by
316 * iicbus_start() call
317 */
318 int
iicbus_write(device_t bus,const char * buf,int len,int * sent,int timeout)319 iicbus_write(device_t bus, const char *buf, int len, int *sent, int timeout)
320 {
321 struct iicbus_softc *sc = (struct iicbus_softc *)device_get_softc(bus);
322
323 /* a slave must have been started for writing */
324 if (sc->started == 0 || (sc->strict != 0 && (sc->started & LSB) != 0))
325 return (IIC_ESTATUS);
326
327 return (IICBUS_WRITE(device_get_parent(bus), buf, len, sent, timeout));
328 }
329
330 /*
331 * iicbus_read()
332 *
333 * Read a block of data from the slave previously started by
334 * iicbus_read() call
335 */
336 int
iicbus_read(device_t bus,char * buf,int len,int * read,int last,int delay)337 iicbus_read(device_t bus, char *buf, int len, int *read, int last, int delay)
338 {
339 struct iicbus_softc *sc = (struct iicbus_softc *)device_get_softc(bus);
340
341 /* a slave must have been started for reading */
342 if (sc->started == 0 || (sc->strict != 0 && (sc->started & LSB) == 0))
343 return (IIC_ESTATUS);
344
345 return (IICBUS_READ(device_get_parent(bus), buf, len, read, last, delay));
346 }
347
348 /*
349 * iicbus_write_byte()
350 *
351 * Write a byte to the slave previously started by iicbus_start() call
352 */
353 int
iicbus_write_byte(device_t bus,char byte,int timeout)354 iicbus_write_byte(device_t bus, char byte, int timeout)
355 {
356 struct iicbus_softc *sc = device_get_softc(bus);
357 char data = byte;
358 int sent;
359
360 /* a slave must have been started for writing */
361 if (sc->started == 0 || (sc->strict != 0 && (sc->started & LSB) != 0))
362 return (IIC_ESTATUS);
363
364 return (iicbus_write(bus, &data, 1, &sent, timeout));
365 }
366
367 /*
368 * iicbus_read_byte()
369 *
370 * Read a byte from the slave previously started by iicbus_start() call
371 */
372 int
iicbus_read_byte(device_t bus,char * byte,int timeout)373 iicbus_read_byte(device_t bus, char *byte, int timeout)
374 {
375 struct iicbus_softc *sc = device_get_softc(bus);
376 int read;
377
378 /* a slave must have been started for reading */
379 if (sc->started == 0 || (sc->strict != 0 && (sc->started & LSB) == 0))
380 return (IIC_ESTATUS);
381
382 return (iicbus_read(bus, byte, 1, &read, IIC_LAST_READ, timeout));
383 }
384
385 /*
386 * iicbus_block_write()
387 *
388 * Write a block of data to slave ; start/stop protocol managed
389 */
390 int
iicbus_block_write(device_t bus,u_char slave,char * buf,int len,int * sent)391 iicbus_block_write(device_t bus, u_char slave, char *buf, int len, int *sent)
392 {
393 u_char addr = slave & ~LSB;
394 int error;
395
396 if ((error = iicbus_start(bus, addr, 0)))
397 return (error);
398
399 error = iicbus_write(bus, buf, len, sent, 0);
400
401 iicbus_stop(bus);
402
403 return (error);
404 }
405
406 /*
407 * iicbus_block_read()
408 *
409 * Read a block of data from slave ; start/stop protocol managed
410 */
411 int
iicbus_block_read(device_t bus,u_char slave,char * buf,int len,int * read)412 iicbus_block_read(device_t bus, u_char slave, char *buf, int len, int *read)
413 {
414 u_char addr = slave | LSB;
415 int error;
416
417 if ((error = iicbus_start(bus, addr, 0)))
418 return (error);
419
420 error = iicbus_read(bus, buf, len, read, IIC_LAST_READ, 0);
421
422 iicbus_stop(bus);
423
424 return (error);
425 }
426
427 /*
428 * iicbus_transfer()
429 *
430 * Do an aribtrary number of transfers on the iicbus. We pass these
431 * raw requests to the bridge driver. If the bridge driver supports
432 * them directly, then it manages all the details. If not, it can use
433 * the helper function iicbus_transfer_gen() which will do the
434 * transfers at a low level.
435 *
436 * Pointers passed in as part of iic_msg must be kernel pointers.
437 * Callers that have user addresses to manage must do so on their own.
438 */
439 int
iicbus_transfer(device_t bus,struct iic_msg * msgs,uint32_t nmsgs)440 iicbus_transfer(device_t bus, struct iic_msg *msgs, uint32_t nmsgs)
441 {
442
443 return (IICBUS_TRANSFER(device_get_parent(bus), msgs, nmsgs));
444 }
445
446 int
iicbus_transfer_excl(device_t dev,struct iic_msg * msgs,uint32_t nmsgs,int how)447 iicbus_transfer_excl(device_t dev, struct iic_msg *msgs, uint32_t nmsgs,
448 int how)
449 {
450 device_t bus;
451 int error;
452
453 bus = device_get_parent(dev);
454 error = iicbus_request_bus(bus, dev, how);
455 if (error == 0)
456 error = IICBUS_TRANSFER(bus, msgs, nmsgs);
457 iicbus_release_bus(bus, dev);
458 return (error);
459 }
460
461 /*
462 * Generic version of iicbus_transfer that calls the appropriate
463 * routines to accomplish this. See note above about acceptable
464 * buffer addresses.
465 */
466 int
iicbus_transfer_gen(device_t dev,struct iic_msg * msgs,uint32_t nmsgs)467 iicbus_transfer_gen(device_t dev, struct iic_msg *msgs, uint32_t nmsgs)
468 {
469 int i, error, lenread, lenwrote, nkid, rpstart, addr;
470 device_t *children, bus;
471 bool started;
472
473 if ((error = device_get_children(dev, &children, &nkid)) != 0)
474 return (IIC_ERESOURCE);
475 if (nkid != 1) {
476 free(children, M_TEMP);
477 return (IIC_ENOTSUPP);
478 }
479 bus = children[0];
480 rpstart = 0;
481 free(children, M_TEMP);
482 started = false;
483 for (i = 0, error = 0; i < nmsgs && error == 0; i++) {
484 addr = msgs[i].slave;
485 if (msgs[i].flags & IIC_M_RD)
486 addr |= LSB;
487 else
488 addr &= ~LSB;
489
490 if (!(msgs[i].flags & IIC_M_NOSTART)) {
491 if (rpstart)
492 error = iicbus_repeated_start(bus, addr, 0);
493 else
494 error = iicbus_start(bus, addr, 0);
495 if (error != 0)
496 break;
497 started = true;
498 }
499
500 if (msgs[i].flags & IIC_M_RD)
501 error = iicbus_read(bus, msgs[i].buf, msgs[i].len,
502 &lenread, IIC_LAST_READ, 0);
503 else
504 error = iicbus_write(bus, msgs[i].buf, msgs[i].len,
505 &lenwrote, 0);
506 if (error != 0)
507 break;
508
509 if (!(msgs[i].flags & IIC_M_NOSTOP)) {
510 rpstart = 0;
511 iicbus_stop(bus);
512 } else {
513 rpstart = 1; /* Next message gets repeated start */
514 }
515 }
516 if (error != 0 && started)
517 iicbus_stop(bus);
518 return (error);
519 }
520
521 int
iicdev_readfrom(device_t slavedev,uint8_t regaddr,void * buffer,uint16_t buflen,int waithow)522 iicdev_readfrom(device_t slavedev, uint8_t regaddr, void *buffer,
523 uint16_t buflen, int waithow)
524 {
525 struct iic_msg msgs[2];
526 uint8_t slaveaddr;
527
528 /*
529 * Two transfers back to back with a repeat-start between them; first we
530 * write the address-within-device, then we read from the device.
531 */
532 slaveaddr = iicbus_get_addr(slavedev);
533
534 msgs[0].slave = slaveaddr;
535 msgs[0].flags = IIC_M_WR | IIC_M_NOSTOP;
536 msgs[0].len = 1;
537 msgs[0].buf = ®addr;
538
539 msgs[1].slave = slaveaddr;
540 msgs[1].flags = IIC_M_RD;
541 msgs[1].len = buflen;
542 msgs[1].buf = buffer;
543
544 return (iicbus_transfer_excl(slavedev, msgs, nitems(msgs), waithow));
545 }
546
iicdev_writeto(device_t slavedev,uint8_t regaddr,void * buffer,uint16_t buflen,int waithow)547 int iicdev_writeto(device_t slavedev, uint8_t regaddr, void *buffer,
548 uint16_t buflen, int waithow)
549 {
550 struct iic_msg msg;
551 uint8_t local_buffer[32];
552 uint8_t *bufptr;
553 size_t bufsize;
554 int error;
555
556 /*
557 * Ideally, we would do two transfers back to back with no stop or start
558 * between them using an array of 2 iic_msgs; first we'd write the
559 * address byte using the IIC_M_NOSTOP flag, then we write the data
560 * using IIC_M_NOSTART, all in a single transfer. Unfortunately,
561 * several i2c hardware drivers don't support that (perhaps because the
562 * hardware itself can't support it). So instead we gather the
563 * scattered bytes into a single buffer here before writing them using a
564 * single iic_msg. This function is typically used to write a few bytes
565 * at a time, so we try to use a small local buffer on the stack, but
566 * fall back to allocating a temporary buffer when necessary.
567 */
568
569 bufsize = buflen + 1;
570 if (bufsize <= sizeof(local_buffer)) {
571 bufptr = local_buffer;
572 } else {
573 bufptr = malloc(bufsize, M_DEVBUF,
574 (waithow & IIC_WAIT) ? M_WAITOK : M_NOWAIT);
575 if (bufptr == NULL)
576 return (errno2iic(ENOMEM));
577 }
578
579 bufptr[0] = regaddr;
580 memcpy(&bufptr[1], buffer, buflen);
581
582 msg.slave = iicbus_get_addr(slavedev);
583 msg.flags = IIC_M_WR;
584 msg.len = bufsize;
585 msg.buf = bufptr;
586
587 error = iicbus_transfer_excl(slavedev, &msg, 1, waithow);
588
589 if (bufptr != local_buffer)
590 free(bufptr, M_DEVBUF);
591
592 return (error);
593 }
594