xref: /freebsd/sys/dev/iicbus/iiconf.c (revision f1951fd745b894fe6586c298874af98544a5e272)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
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 __FBSDID("$FreeBSD$");
31 
32 #include <sys/param.h>
33 #include <sys/systm.h>
34 #include <sys/lock.h>
35 #include <sys/malloc.h>
36 #include <sys/module.h>
37 #include <sys/mutex.h>
38 #include <sys/bus.h>
39 
40 #include <dev/iicbus/iiconf.h>
41 #include <dev/iicbus/iicbus.h>
42 #include "iicbus_if.h"
43 
44 /*
45  * Translate IIC_Exxxxx status values to vaguely-equivelent errno values.
46  */
47 int
48 iic2errno(int iic_status)
49 {
50 	switch (iic_status) {
51 	case IIC_NOERR:         return (0);
52 	case IIC_EBUSERR:       return (EALREADY);
53 	case IIC_ENOACK:        return (EIO);
54 	case IIC_ETIMEOUT:      return (ETIMEDOUT);
55 	case IIC_EBUSBSY:       return (EWOULDBLOCK);
56 	case IIC_ESTATUS:       return (EPROTO);
57 	case IIC_EUNDERFLOW:    return (EIO);
58 	case IIC_EOVERFLOW:     return (EOVERFLOW);
59 	case IIC_ENOTSUPP:      return (EOPNOTSUPP);
60 	case IIC_ENOADDR:       return (EADDRNOTAVAIL);
61 	case IIC_ERESOURCE:     return (ENOMEM);
62 	default:                return (EIO);
63 	}
64 }
65 
66 /*
67  * iicbus_intr()
68  */
69 void
70 iicbus_intr(device_t bus, int event, char *buf)
71 {
72 	struct iicbus_softc *sc = (struct iicbus_softc *)device_get_softc(bus);
73 
74 	/* call owner's intr routine */
75 	if (sc->owner)
76 		IICBUS_INTR(sc->owner, event, buf);
77 
78 	return;
79 }
80 
81 static int
82 iicbus_poll(struct iicbus_softc *sc, int how)
83 {
84 	int error;
85 
86 	IICBUS_ASSERT_LOCKED(sc);
87 	switch (how & IIC_INTRWAIT) {
88 	case IIC_WAIT | IIC_INTR:
89 		error = mtx_sleep(sc, &sc->lock, IICPRI|PCATCH, "iicreq", 0);
90 		break;
91 
92 	case IIC_WAIT | IIC_NOINTR:
93 		error = mtx_sleep(sc, &sc->lock, IICPRI, "iicreq", 0);
94 		break;
95 
96 	default:
97 		return (IIC_EBUSBSY);
98 	}
99 
100 	return (error);
101 }
102 
103 /*
104  * iicbus_request_bus()
105  *
106  * Allocate the device to perform transfers.
107  *
108  * how	: IIC_WAIT or IIC_DONTWAIT
109  */
110 int
111 iicbus_request_bus(device_t bus, device_t dev, int how)
112 {
113 	struct iicbus_softc *sc = (struct iicbus_softc *)device_get_softc(bus);
114 	int error = 0;
115 
116 	IICBUS_LOCK(sc);
117 
118 	for (;;) {
119 		if (sc->owner == NULL)
120 			break;
121 		if ((how & IIC_RECURSIVE) && sc->owner == dev)
122 			break;
123 		if ((error = iicbus_poll(sc, how)) != 0)
124 			break;
125 	}
126 
127 	if (error == 0) {
128 		++sc->owncount;
129 		if (sc->owner == NULL) {
130 			sc->owner = dev;
131 			/*
132 			 * Drop the lock around the call to the bus driver, it
133 			 * should be allowed to sleep in the IIC_WAIT case.
134 			 * Drivers might also need to grab locks that would
135 			 * cause a LOR if our lock is held.
136 			 */
137 			IICBUS_UNLOCK(sc);
138 			/* Ask the underlying layers if the request is ok */
139 			error = IICBUS_CALLBACK(device_get_parent(bus),
140 			    IIC_REQUEST_BUS, (caddr_t)&how);
141 			IICBUS_LOCK(sc);
142 
143 			if (error != 0) {
144 				sc->owner = NULL;
145 				sc->owncount = 0;
146 				wakeup_one(sc);
147 			}
148 		}
149 	}
150 
151 	IICBUS_UNLOCK(sc);
152 
153 	return (error);
154 }
155 
156 /*
157  * iicbus_release_bus()
158  *
159  * Release the device allocated with iicbus_request_dev()
160  */
161 int
162 iicbus_release_bus(device_t bus, device_t dev)
163 {
164 	struct iicbus_softc *sc = (struct iicbus_softc *)device_get_softc(bus);
165 
166 	IICBUS_LOCK(sc);
167 
168 	if (sc->owner != dev) {
169 		IICBUS_UNLOCK(sc);
170 		return (IIC_EBUSBSY);
171 	}
172 
173 	if (--sc->owncount == 0) {
174 		/* Drop the lock while informing the low-level driver. */
175 		IICBUS_UNLOCK(sc);
176 		IICBUS_CALLBACK(device_get_parent(bus), IIC_RELEASE_BUS, NULL);
177 		IICBUS_LOCK(sc);
178 		sc->owner = NULL;
179 		wakeup_one(sc);
180 	}
181 	IICBUS_UNLOCK(sc);
182 	return (0);
183 }
184 
185 /*
186  * iicbus_started()
187  *
188  * Test if the iicbus is started by the controller
189  */
190 int
191 iicbus_started(device_t bus)
192 {
193 	struct iicbus_softc *sc = (struct iicbus_softc *)device_get_softc(bus);
194 
195 	return (sc->started);
196 }
197 
198 /*
199  * iicbus_start()
200  *
201  * Send start condition to the slave addressed by 'slave'
202  */
203 int
204 iicbus_start(device_t bus, u_char slave, int timeout)
205 {
206 	struct iicbus_softc *sc = (struct iicbus_softc *)device_get_softc(bus);
207 	int error = 0;
208 
209 	if (sc->started)
210 		return (IIC_ESTATUS); /* protocol error, bus already started */
211 
212 	if (!(error = IICBUS_START(device_get_parent(bus), slave, timeout)))
213 		sc->started = slave;
214 	else
215 		sc->started = 0;
216 
217 	return (error);
218 }
219 
220 /*
221  * iicbus_repeated_start()
222  *
223  * Send start condition to the slave addressed by 'slave'
224  */
225 int
226 iicbus_repeated_start(device_t bus, u_char slave, int timeout)
227 {
228 	struct iicbus_softc *sc = (struct iicbus_softc *)device_get_softc(bus);
229 	int error = 0;
230 
231 	if (!sc->started)
232 		return (IIC_ESTATUS); /* protocol error, bus not started */
233 
234 	if (!(error = IICBUS_REPEATED_START(device_get_parent(bus), slave, timeout)))
235 		sc->started = slave;
236 	else
237 		sc->started = 0;
238 
239 	return (error);
240 }
241 
242 /*
243  * iicbus_stop()
244  *
245  * Send stop condition to the bus
246  */
247 int
248 iicbus_stop(device_t bus)
249 {
250 	struct iicbus_softc *sc = (struct iicbus_softc *)device_get_softc(bus);
251 	int error = 0;
252 
253 	if (!sc->started)
254 		return (IIC_ESTATUS); /* protocol error, bus not started */
255 
256 	error = IICBUS_STOP(device_get_parent(bus));
257 
258 	/* refuse any further access */
259 	sc->started = 0;
260 
261 	return (error);
262 }
263 
264 /*
265  * iicbus_write()
266  *
267  * Write a block of data to the slave previously started by
268  * iicbus_start() call
269  */
270 int
271 iicbus_write(device_t bus, const char *buf, int len, int *sent, int timeout)
272 {
273 	struct iicbus_softc *sc = (struct iicbus_softc *)device_get_softc(bus);
274 
275 	/* a slave must have been started for writing */
276 	if (sc->started == 0 || (sc->strict != 0 && (sc->started & LSB) != 0))
277 		return (IIC_ESTATUS);
278 
279 	return (IICBUS_WRITE(device_get_parent(bus), buf, len, sent, timeout));
280 }
281 
282 /*
283  * iicbus_read()
284  *
285  * Read a block of data from the slave previously started by
286  * iicbus_read() call
287  */
288 int
289 iicbus_read(device_t bus, char *buf, int len, int *read, int last, int delay)
290 {
291 	struct iicbus_softc *sc = (struct iicbus_softc *)device_get_softc(bus);
292 
293 	/* a slave must have been started for reading */
294 	if (sc->started == 0 || (sc->strict != 0 && (sc->started & LSB) == 0))
295 		return (IIC_ESTATUS);
296 
297 	return (IICBUS_READ(device_get_parent(bus), buf, len, read, last, delay));
298 }
299 
300 /*
301  * iicbus_write_byte()
302  *
303  * Write a byte to the slave previously started by iicbus_start() call
304  */
305 int
306 iicbus_write_byte(device_t bus, char byte, int timeout)
307 {
308 	struct iicbus_softc *sc = device_get_softc(bus);
309 	char data = byte;
310 	int sent;
311 
312 	/* a slave must have been started for writing */
313 	if (sc->started == 0 || (sc->strict != 0 && (sc->started & LSB) != 0))
314 		return (IIC_ESTATUS);
315 
316 	return (iicbus_write(bus, &data, 1, &sent, timeout));
317 }
318 
319 /*
320  * iicbus_read_byte()
321  *
322  * Read a byte from the slave previously started by iicbus_start() call
323  */
324 int
325 iicbus_read_byte(device_t bus, char *byte, int timeout)
326 {
327 	struct iicbus_softc *sc = device_get_softc(bus);
328 	int read;
329 
330 	/* a slave must have been started for reading */
331 	if (sc->started == 0 || (sc->strict != 0 && (sc->started & LSB) == 0))
332 		return (IIC_ESTATUS);
333 
334 	return (iicbus_read(bus, byte, 1, &read, IIC_LAST_READ, timeout));
335 }
336 
337 /*
338  * iicbus_block_write()
339  *
340  * Write a block of data to slave ; start/stop protocol managed
341  */
342 int
343 iicbus_block_write(device_t bus, u_char slave, char *buf, int len, int *sent)
344 {
345 	u_char addr = slave & ~LSB;
346 	int error;
347 
348 	if ((error = iicbus_start(bus, addr, 0)))
349 		return (error);
350 
351 	error = iicbus_write(bus, buf, len, sent, 0);
352 
353 	iicbus_stop(bus);
354 
355 	return (error);
356 }
357 
358 /*
359  * iicbus_block_read()
360  *
361  * Read a block of data from slave ; start/stop protocol managed
362  */
363 int
364 iicbus_block_read(device_t bus, u_char slave, char *buf, int len, int *read)
365 {
366 	u_char addr = slave | LSB;
367 	int error;
368 
369 	if ((error = iicbus_start(bus, addr, 0)))
370 		return (error);
371 
372 	error = iicbus_read(bus, buf, len, read, IIC_LAST_READ, 0);
373 
374 	iicbus_stop(bus);
375 
376 	return (error);
377 }
378 
379 /*
380  * iicbus_transfer()
381  *
382  * Do an aribtrary number of transfers on the iicbus.  We pass these
383  * raw requests to the bridge driver.  If the bridge driver supports
384  * them directly, then it manages all the details.  If not, it can use
385  * the helper function iicbus_transfer_gen() which will do the
386  * transfers at a low level.
387  *
388  * Pointers passed in as part of iic_msg must be kernel pointers.
389  * Callers that have user addresses to manage must do so on their own.
390  */
391 int
392 iicbus_transfer(device_t bus, struct iic_msg *msgs, uint32_t nmsgs)
393 {
394 
395 	return (IICBUS_TRANSFER(device_get_parent(bus), msgs, nmsgs));
396 }
397 
398 int
399 iicbus_transfer_excl(device_t dev, struct iic_msg *msgs, uint32_t nmsgs,
400     int how)
401 {
402 	device_t bus;
403 	int error;
404 
405 	bus = device_get_parent(dev);
406 	error = iicbus_request_bus(bus, dev, how);
407 	if (error == 0)
408 		error = IICBUS_TRANSFER(bus, msgs, nmsgs);
409 	iicbus_release_bus(bus, dev);
410 	return (error);
411 }
412 
413 /*
414  * Generic version of iicbus_transfer that calls the appropriate
415  * routines to accomplish this.  See note above about acceptable
416  * buffer addresses.
417  */
418 int
419 iicbus_transfer_gen(device_t dev, struct iic_msg *msgs, uint32_t nmsgs)
420 {
421 	int i, error, lenread, lenwrote, nkid, rpstart, addr;
422 	device_t *children, bus;
423 	bool nostop, started;
424 
425 	if ((error = device_get_children(dev, &children, &nkid)) != 0)
426 		return (IIC_ERESOURCE);
427 	if (nkid != 1) {
428 		free(children, M_TEMP);
429 		return (IIC_ENOTSUPP);
430 	}
431 	bus = children[0];
432 	rpstart = 0;
433 	free(children, M_TEMP);
434 	nostop = iicbus_get_nostop(dev);
435 	started = false;
436 	for (i = 0, error = 0; i < nmsgs && error == 0; i++) {
437 		addr = msgs[i].slave;
438 		if (msgs[i].flags & IIC_M_RD)
439 			addr |= LSB;
440 		else
441 			addr &= ~LSB;
442 
443 		if (!(msgs[i].flags & IIC_M_NOSTART)) {
444 			if (rpstart)
445 				error = iicbus_repeated_start(bus, addr, 0);
446 			else
447 				error = iicbus_start(bus, addr, 0);
448 			if (error != 0)
449 				break;
450 			started = true;
451 		}
452 
453 		if (msgs[i].flags & IIC_M_RD)
454 			error = iicbus_read(bus, msgs[i].buf, msgs[i].len,
455 			    &lenread, IIC_LAST_READ, 0);
456 		else
457 			error = iicbus_write(bus, msgs[i].buf, msgs[i].len,
458 			    &lenwrote, 0);
459 		if (error != 0)
460 			break;
461 
462 		if ((msgs[i].flags & IIC_M_NOSTOP) != 0 ||
463 		    (nostop && i + 1 < nmsgs)) {
464 			rpstart = 1;	/* Next message gets repeated start */
465 		} else {
466 			rpstart = 0;
467 			iicbus_stop(bus);
468 		}
469 	}
470 	if (error != 0 && started)
471 		iicbus_stop(bus);
472 	return (error);
473 }
474 
475 int
476 iicdev_readfrom(device_t slavedev, uint8_t regaddr, void *buffer,
477     uint16_t buflen, int waithow)
478 {
479 	struct iic_msg msgs[2];
480 	uint8_t slaveaddr;
481 
482 	/*
483 	 * Two transfers back to back with a repeat-start between them; first we
484 	 * write the address-within-device, then we read from the device.
485 	 */
486 	slaveaddr = iicbus_get_addr(slavedev);
487 
488 	msgs[0].slave = slaveaddr;
489 	msgs[0].flags = IIC_M_WR | IIC_M_NOSTOP;
490 	msgs[0].len   = 1;
491 	msgs[0].buf   = &regaddr;
492 
493 	msgs[1].slave = slaveaddr;
494 	msgs[1].flags = IIC_M_RD;
495 	msgs[1].len   = buflen;
496 	msgs[1].buf   = buffer;
497 
498 	return (iicbus_transfer_excl(slavedev, msgs, nitems(msgs), waithow));
499 }
500 
501 int iicdev_writeto(device_t slavedev, uint8_t regaddr, void *buffer,
502     uint16_t buflen, int waithow)
503 {
504 	struct iic_msg msgs[2];
505 	uint8_t slaveaddr;
506 
507 	/*
508 	 * Two transfers back to back with no stop or start between them; first
509 	 * we write the address then we write the data to that address, all in a
510 	 * single transfer from two scattered buffers.
511 	 */
512 	slaveaddr = iicbus_get_addr(slavedev);
513 
514 	msgs[0].slave = slaveaddr;
515 	msgs[0].flags = IIC_M_WR | IIC_M_NOSTOP;
516 	msgs[0].len   = 1;
517 	msgs[0].buf   = &regaddr;
518 
519 	msgs[1].slave = slaveaddr;
520 	msgs[1].flags = IIC_M_WR | IIC_M_NOSTART;
521 	msgs[1].len   = buflen;
522 	msgs[1].buf   = buffer;
523 
524 	return (iicbus_transfer_excl(slavedev, msgs, nitems(msgs), waithow));
525 }
526