2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
4 * Copyright (c) 1998 Nicolas Souchu
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
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.
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
29 #include <sys/cdefs.h>
30 __FBSDID("$FreeBSD$");
32 #include <sys/param.h>
33 #include <sys/systm.h>
35 #include <sys/malloc.h>
36 #include <sys/module.h>
37 #include <sys/mutex.h>
40 #include <dev/iicbus/iiconf.h>
41 #include <dev/iicbus/iicbus.h>
42 #include "iicbus_if.h"
45 * Encode a system errno value into the IIC_Exxxxx space by setting the
46 * IIC_ERRNO marker bit, so that iic2errno() can turn it back into a plain
47 * system errno value later. This lets controller- and bus-layer code get
48 * important system errno values (such as EINTR/ERESTART) back to the caller.
53 return ((errno == 0) ? 0 : errno | IIC_ERRNO);
57 * Translate IIC_Exxxxx status values to vaguely-equivelent errno values.
60 iic2errno(int iic_status)
63 case IIC_NOERR: return (0);
64 case IIC_EBUSERR: return (EALREADY);
65 case IIC_ENOACK: return (EIO);
66 case IIC_ETIMEOUT: return (ETIMEDOUT);
67 case IIC_EBUSBSY: return (EWOULDBLOCK);
68 case IIC_ESTATUS: return (EPROTO);
69 case IIC_EUNDERFLOW: return (EIO);
70 case IIC_EOVERFLOW: return (EOVERFLOW);
71 case IIC_ENOTSUPP: return (EOPNOTSUPP);
72 case IIC_ENOADDR: return (EADDRNOTAVAIL);
73 case IIC_ERESOURCE: return (ENOMEM);
76 * If the high bit is set, that means it's a system errno value
77 * that was encoded into the IIC_Exxxxxx space by setting the
78 * IIC_ERRNO marker bit. If lots of high-order bits are set,
79 * then it's one of the negative pseudo-errors such as ERESTART
80 * and we return it as-is. Otherwise it's a plain "small
81 * positive integer" errno, so just remove the IIC_ERRNO marker
82 * bit. If it's some unknown number without the high bit set,
83 * there isn't much we can do except call it an I/O error.
85 if ((iic_status & IIC_ERRNO) == 0)
87 if ((iic_status & 0xFFFF0000) != 0)
89 return (iic_status & ~IIC_ERRNO);
97 iicbus_intr(device_t bus, int event, char *buf)
99 struct iicbus_softc *sc = (struct iicbus_softc *)device_get_softc(bus);
101 /* call owner's intr routine */
103 IICBUS_INTR(sc->owner, event, buf);
109 iicbus_poll(struct iicbus_softc *sc, int how)
113 IICBUS_ASSERT_LOCKED(sc);
114 switch (how & IIC_INTRWAIT) {
115 case IIC_WAIT | IIC_INTR:
116 error = mtx_sleep(sc, &sc->lock, IICPRI|PCATCH, "iicreq", 0);
119 case IIC_WAIT | IIC_NOINTR:
120 error = mtx_sleep(sc, &sc->lock, IICPRI, "iicreq", 0);
124 return (IIC_EBUSBSY);
127 return (errno2iic(error));
131 * iicbus_request_bus()
133 * Allocate the device to perform transfers.
135 * how : IIC_WAIT or IIC_DONTWAIT
138 iicbus_request_bus(device_t bus, device_t dev, int how)
140 struct iicbus_softc *sc = (struct iicbus_softc *)device_get_softc(bus);
146 if (sc->owner == NULL)
148 if ((how & IIC_RECURSIVE) && sc->owner == dev)
150 if ((error = iicbus_poll(sc, how)) != 0)
156 if (sc->owner == NULL) {
159 * Mark the device busy while it owns the bus, to
160 * prevent detaching the device, bus, or hardware
161 * controller, until ownership is relinquished. If the
162 * device is doing IO from its probe method before
163 * attaching, it cannot be busied; mark the bus busy.
165 if (device_get_state(dev) < DS_ATTACHING)
169 device_busy(sc->busydev);
171 * Drop the lock around the call to the bus driver, it
172 * should be allowed to sleep in the IIC_WAIT case.
173 * Drivers might also need to grab locks that would
174 * cause a LOR if our lock is held.
177 /* Ask the underlying layers if the request is ok */
178 error = IICBUS_CALLBACK(device_get_parent(bus),
179 IIC_REQUEST_BUS, (caddr_t)&how);
186 device_unbusy(sc->busydev);
197 * iicbus_release_bus()
199 * Release the device allocated with iicbus_request_dev()
202 iicbus_release_bus(device_t bus, device_t dev)
204 struct iicbus_softc *sc = (struct iicbus_softc *)device_get_softc(bus);
208 if (sc->owner != dev) {
210 return (IIC_EBUSBSY);
213 if (--sc->owncount == 0) {
214 /* Drop the lock while informing the low-level driver. */
216 IICBUS_CALLBACK(device_get_parent(bus), IIC_RELEASE_BUS, NULL);
220 device_unbusy(sc->busydev);
229 * Test if the iicbus is started by the controller
232 iicbus_started(device_t bus)
234 struct iicbus_softc *sc = (struct iicbus_softc *)device_get_softc(bus);
236 return (sc->started);
242 * Send start condition to the slave addressed by 'slave'
245 iicbus_start(device_t bus, u_char slave, int timeout)
247 struct iicbus_softc *sc = (struct iicbus_softc *)device_get_softc(bus);
251 return (IIC_ESTATUS); /* protocol error, bus already started */
253 if (!(error = IICBUS_START(device_get_parent(bus), slave, timeout)))
262 * iicbus_repeated_start()
264 * Send start condition to the slave addressed by 'slave'
267 iicbus_repeated_start(device_t bus, u_char slave, int timeout)
269 struct iicbus_softc *sc = (struct iicbus_softc *)device_get_softc(bus);
273 return (IIC_ESTATUS); /* protocol error, bus not started */
275 if (!(error = IICBUS_REPEATED_START(device_get_parent(bus), slave, timeout)))
286 * Send stop condition to the bus
289 iicbus_stop(device_t bus)
291 struct iicbus_softc *sc = (struct iicbus_softc *)device_get_softc(bus);
295 return (IIC_ESTATUS); /* protocol error, bus not started */
297 error = IICBUS_STOP(device_get_parent(bus));
299 /* refuse any further access */
308 * Write a block of data to the slave previously started by
309 * iicbus_start() call
312 iicbus_write(device_t bus, const char *buf, int len, int *sent, int timeout)
314 struct iicbus_softc *sc = (struct iicbus_softc *)device_get_softc(bus);
316 /* a slave must have been started for writing */
317 if (sc->started == 0 || (sc->strict != 0 && (sc->started & LSB) != 0))
318 return (IIC_ESTATUS);
320 return (IICBUS_WRITE(device_get_parent(bus), buf, len, sent, timeout));
326 * Read a block of data from the slave previously started by
330 iicbus_read(device_t bus, char *buf, int len, int *read, int last, int delay)
332 struct iicbus_softc *sc = (struct iicbus_softc *)device_get_softc(bus);
334 /* a slave must have been started for reading */
335 if (sc->started == 0 || (sc->strict != 0 && (sc->started & LSB) == 0))
336 return (IIC_ESTATUS);
338 return (IICBUS_READ(device_get_parent(bus), buf, len, read, last, delay));
342 * iicbus_write_byte()
344 * Write a byte to the slave previously started by iicbus_start() call
347 iicbus_write_byte(device_t bus, char byte, int timeout)
349 struct iicbus_softc *sc = device_get_softc(bus);
353 /* a slave must have been started for writing */
354 if (sc->started == 0 || (sc->strict != 0 && (sc->started & LSB) != 0))
355 return (IIC_ESTATUS);
357 return (iicbus_write(bus, &data, 1, &sent, timeout));
363 * Read a byte from the slave previously started by iicbus_start() call
366 iicbus_read_byte(device_t bus, char *byte, int timeout)
368 struct iicbus_softc *sc = device_get_softc(bus);
371 /* a slave must have been started for reading */
372 if (sc->started == 0 || (sc->strict != 0 && (sc->started & LSB) == 0))
373 return (IIC_ESTATUS);
375 return (iicbus_read(bus, byte, 1, &read, IIC_LAST_READ, timeout));
379 * iicbus_block_write()
381 * Write a block of data to slave ; start/stop protocol managed
384 iicbus_block_write(device_t bus, u_char slave, char *buf, int len, int *sent)
386 u_char addr = slave & ~LSB;
389 if ((error = iicbus_start(bus, addr, 0)))
392 error = iicbus_write(bus, buf, len, sent, 0);
400 * iicbus_block_read()
402 * Read a block of data from slave ; start/stop protocol managed
405 iicbus_block_read(device_t bus, u_char slave, char *buf, int len, int *read)
407 u_char addr = slave | LSB;
410 if ((error = iicbus_start(bus, addr, 0)))
413 error = iicbus_read(bus, buf, len, read, IIC_LAST_READ, 0);
423 * Do an aribtrary number of transfers on the iicbus. We pass these
424 * raw requests to the bridge driver. If the bridge driver supports
425 * them directly, then it manages all the details. If not, it can use
426 * the helper function iicbus_transfer_gen() which will do the
427 * transfers at a low level.
429 * Pointers passed in as part of iic_msg must be kernel pointers.
430 * Callers that have user addresses to manage must do so on their own.
433 iicbus_transfer(device_t bus, struct iic_msg *msgs, uint32_t nmsgs)
436 return (IICBUS_TRANSFER(device_get_parent(bus), msgs, nmsgs));
440 iicbus_transfer_excl(device_t dev, struct iic_msg *msgs, uint32_t nmsgs,
446 bus = device_get_parent(dev);
447 error = iicbus_request_bus(bus, dev, how);
449 error = IICBUS_TRANSFER(bus, msgs, nmsgs);
450 iicbus_release_bus(bus, dev);
455 * Generic version of iicbus_transfer that calls the appropriate
456 * routines to accomplish this. See note above about acceptable
460 iicbus_transfer_gen(device_t dev, struct iic_msg *msgs, uint32_t nmsgs)
462 int i, error, lenread, lenwrote, nkid, rpstart, addr;
463 device_t *children, bus;
466 if ((error = device_get_children(dev, &children, &nkid)) != 0)
467 return (IIC_ERESOURCE);
469 free(children, M_TEMP);
470 return (IIC_ENOTSUPP);
474 free(children, M_TEMP);
476 for (i = 0, error = 0; i < nmsgs && error == 0; i++) {
477 addr = msgs[i].slave;
478 if (msgs[i].flags & IIC_M_RD)
483 if (!(msgs[i].flags & IIC_M_NOSTART)) {
485 error = iicbus_repeated_start(bus, addr, 0);
487 error = iicbus_start(bus, addr, 0);
493 if (msgs[i].flags & IIC_M_RD)
494 error = iicbus_read(bus, msgs[i].buf, msgs[i].len,
495 &lenread, IIC_LAST_READ, 0);
497 error = iicbus_write(bus, msgs[i].buf, msgs[i].len,
502 if (!(msgs[i].flags & IIC_M_NOSTOP)) {
506 rpstart = 1; /* Next message gets repeated start */
509 if (error != 0 && started)
515 iicdev_readfrom(device_t slavedev, uint8_t regaddr, void *buffer,
516 uint16_t buflen, int waithow)
518 struct iic_msg msgs[2];
522 * Two transfers back to back with a repeat-start between them; first we
523 * write the address-within-device, then we read from the device.
525 slaveaddr = iicbus_get_addr(slavedev);
527 msgs[0].slave = slaveaddr;
528 msgs[0].flags = IIC_M_WR | IIC_M_NOSTOP;
530 msgs[0].buf = ®addr;
532 msgs[1].slave = slaveaddr;
533 msgs[1].flags = IIC_M_RD;
534 msgs[1].len = buflen;
535 msgs[1].buf = buffer;
537 return (iicbus_transfer_excl(slavedev, msgs, nitems(msgs), waithow));
540 int iicdev_writeto(device_t slavedev, uint8_t regaddr, void *buffer,
541 uint16_t buflen, int waithow)
544 uint8_t local_buffer[32];
550 * Ideally, we would do two transfers back to back with no stop or start
551 * between them using an array of 2 iic_msgs; first we'd write the
552 * address byte using the IIC_M_NOSTOP flag, then we write the data
553 * using IIC_M_NOSTART, all in a single transfer. Unfortunately,
554 * several i2c hardware drivers don't support that (perhaps because the
555 * hardware itself can't support it). So instead we gather the
556 * scattered bytes into a single buffer here before writing them using a
557 * single iic_msg. This function is typically used to write a few bytes
558 * at a time, so we try to use a small local buffer on the stack, but
559 * fall back to allocating a temporary buffer when necessary.
562 bufsize = buflen + 1;
563 if (bufsize <= sizeof(local_buffer)) {
564 bufptr = local_buffer;
566 bufptr = malloc(bufsize, M_DEVBUF,
567 (waithow & IIC_WAIT) ? M_WAITOK : M_NOWAIT);
569 return (errno2iic(ENOMEM));
573 memcpy(&bufptr[1], buffer, buflen);
575 msg.slave = iicbus_get_addr(slavedev);
576 msg.flags = IIC_M_WR;
580 error = iicbus_transfer_excl(slavedev, &msg, 1, waithow);
582 if (bufptr != local_buffer)
583 free(bufptr, M_DEVBUF);