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 iic_reqbus_data reqdata;
141 struct iicbus_softc *sc = (struct iicbus_softc *)device_get_softc(bus);
147 if (sc->owner == NULL)
149 if ((how & IIC_RECURSIVE) && sc->owner == dev)
151 if ((error = iicbus_poll(sc, how)) != 0)
157 if (sc->owner == NULL) {
160 * Mark the device busy while it owns the bus, to
161 * prevent detaching the device, bus, or hardware
162 * controller, until ownership is relinquished. If the
163 * device is doing IO from its probe method before
164 * attaching, it cannot be busied; mark the bus busy.
166 if (device_get_state(dev) < DS_ATTACHING)
170 device_busy(sc->busydev);
172 * Drop the lock around the call to the bus driver, it
173 * should be allowed to sleep in the IIC_WAIT case.
174 * Drivers might also need to grab locks that would
175 * cause a LOR if our lock is held.
178 /* Ask the underlying layers if the request is ok */
181 reqdata.flags = how | IIC_REQBUS_DEV;
182 error = IICBUS_CALLBACK(device_get_parent(bus),
183 IIC_REQUEST_BUS, (caddr_t)&reqdata);
190 device_unbusy(sc->busydev);
201 * iicbus_release_bus()
203 * Release the device allocated with iicbus_request_dev()
206 iicbus_release_bus(device_t bus, device_t dev)
208 struct iic_reqbus_data reqdata;
209 struct iicbus_softc *sc = (struct iicbus_softc *)device_get_softc(bus);
213 if (sc->owner != dev) {
215 return (IIC_EBUSBSY);
218 if (--sc->owncount == 0) {
219 /* Drop the lock while informing the low-level driver. */
223 reqdata.flags = IIC_REQBUS_DEV;
224 IICBUS_CALLBACK(device_get_parent(bus), IIC_RELEASE_BUS,
229 device_unbusy(sc->busydev);
238 * Test if the iicbus is started by the controller
241 iicbus_started(device_t bus)
243 struct iicbus_softc *sc = (struct iicbus_softc *)device_get_softc(bus);
245 return (sc->started);
251 * Send start condition to the slave addressed by 'slave'
254 iicbus_start(device_t bus, u_char slave, int timeout)
256 struct iicbus_softc *sc = (struct iicbus_softc *)device_get_softc(bus);
260 return (IIC_ESTATUS); /* protocol error, bus already started */
262 if (!(error = IICBUS_START(device_get_parent(bus), slave, timeout)))
271 * iicbus_repeated_start()
273 * Send start condition to the slave addressed by 'slave'
276 iicbus_repeated_start(device_t bus, u_char slave, int timeout)
278 struct iicbus_softc *sc = (struct iicbus_softc *)device_get_softc(bus);
282 return (IIC_ESTATUS); /* protocol error, bus not started */
284 if (!(error = IICBUS_REPEATED_START(device_get_parent(bus), slave, timeout)))
295 * Send stop condition to the bus
298 iicbus_stop(device_t bus)
300 struct iicbus_softc *sc = (struct iicbus_softc *)device_get_softc(bus);
304 return (IIC_ESTATUS); /* protocol error, bus not started */
306 error = IICBUS_STOP(device_get_parent(bus));
308 /* refuse any further access */
317 * Write a block of data to the slave previously started by
318 * iicbus_start() call
321 iicbus_write(device_t bus, const char *buf, int len, int *sent, int timeout)
323 struct iicbus_softc *sc = (struct iicbus_softc *)device_get_softc(bus);
325 /* a slave must have been started for writing */
326 if (sc->started == 0 || (sc->strict != 0 && (sc->started & LSB) != 0))
327 return (IIC_ESTATUS);
329 return (IICBUS_WRITE(device_get_parent(bus), buf, len, sent, timeout));
335 * Read a block of data from the slave previously started by
339 iicbus_read(device_t bus, char *buf, int len, int *read, int last, int delay)
341 struct iicbus_softc *sc = (struct iicbus_softc *)device_get_softc(bus);
343 /* a slave must have been started for reading */
344 if (sc->started == 0 || (sc->strict != 0 && (sc->started & LSB) == 0))
345 return (IIC_ESTATUS);
347 return (IICBUS_READ(device_get_parent(bus), buf, len, read, last, delay));
351 * iicbus_write_byte()
353 * Write a byte to the slave previously started by iicbus_start() call
356 iicbus_write_byte(device_t bus, char byte, int timeout)
358 struct iicbus_softc *sc = device_get_softc(bus);
362 /* a slave must have been started for writing */
363 if (sc->started == 0 || (sc->strict != 0 && (sc->started & LSB) != 0))
364 return (IIC_ESTATUS);
366 return (iicbus_write(bus, &data, 1, &sent, timeout));
372 * Read a byte from the slave previously started by iicbus_start() call
375 iicbus_read_byte(device_t bus, char *byte, int timeout)
377 struct iicbus_softc *sc = device_get_softc(bus);
380 /* a slave must have been started for reading */
381 if (sc->started == 0 || (sc->strict != 0 && (sc->started & LSB) == 0))
382 return (IIC_ESTATUS);
384 return (iicbus_read(bus, byte, 1, &read, IIC_LAST_READ, timeout));
388 * iicbus_block_write()
390 * Write a block of data to slave ; start/stop protocol managed
393 iicbus_block_write(device_t bus, u_char slave, char *buf, int len, int *sent)
395 u_char addr = slave & ~LSB;
398 if ((error = iicbus_start(bus, addr, 0)))
401 error = iicbus_write(bus, buf, len, sent, 0);
409 * iicbus_block_read()
411 * Read a block of data from slave ; start/stop protocol managed
414 iicbus_block_read(device_t bus, u_char slave, char *buf, int len, int *read)
416 u_char addr = slave | LSB;
419 if ((error = iicbus_start(bus, addr, 0)))
422 error = iicbus_read(bus, buf, len, read, IIC_LAST_READ, 0);
432 * Do an aribtrary number of transfers on the iicbus. We pass these
433 * raw requests to the bridge driver. If the bridge driver supports
434 * them directly, then it manages all the details. If not, it can use
435 * the helper function iicbus_transfer_gen() which will do the
436 * transfers at a low level.
438 * Pointers passed in as part of iic_msg must be kernel pointers.
439 * Callers that have user addresses to manage must do so on their own.
442 iicbus_transfer(device_t bus, struct iic_msg *msgs, uint32_t nmsgs)
445 return (IICBUS_TRANSFER(device_get_parent(bus), msgs, nmsgs));
449 iicbus_transfer_excl(device_t dev, struct iic_msg *msgs, uint32_t nmsgs,
455 bus = device_get_parent(dev);
456 error = iicbus_request_bus(bus, dev, how);
458 error = IICBUS_TRANSFER(bus, msgs, nmsgs);
459 iicbus_release_bus(bus, dev);
464 * Generic version of iicbus_transfer that calls the appropriate
465 * routines to accomplish this. See note above about acceptable
469 iicbus_transfer_gen(device_t dev, struct iic_msg *msgs, uint32_t nmsgs)
471 int i, error, lenread, lenwrote, nkid, rpstart, addr;
472 device_t *children, bus;
475 if ((error = device_get_children(dev, &children, &nkid)) != 0)
476 return (IIC_ERESOURCE);
478 free(children, M_TEMP);
479 return (IIC_ENOTSUPP);
483 free(children, M_TEMP);
485 for (i = 0, error = 0; i < nmsgs && error == 0; i++) {
486 addr = msgs[i].slave;
487 if (msgs[i].flags & IIC_M_RD)
492 if (!(msgs[i].flags & IIC_M_NOSTART)) {
494 error = iicbus_repeated_start(bus, addr, 0);
496 error = iicbus_start(bus, addr, 0);
502 if (msgs[i].flags & IIC_M_RD)
503 error = iicbus_read(bus, msgs[i].buf, msgs[i].len,
504 &lenread, IIC_LAST_READ, 0);
506 error = iicbus_write(bus, msgs[i].buf, msgs[i].len,
511 if (!(msgs[i].flags & IIC_M_NOSTOP)) {
515 rpstart = 1; /* Next message gets repeated start */
518 if (error != 0 && started)
524 iicdev_readfrom(device_t slavedev, uint8_t regaddr, void *buffer,
525 uint16_t buflen, int waithow)
527 struct iic_msg msgs[2];
531 * Two transfers back to back with a repeat-start between them; first we
532 * write the address-within-device, then we read from the device.
534 slaveaddr = iicbus_get_addr(slavedev);
536 msgs[0].slave = slaveaddr;
537 msgs[0].flags = IIC_M_WR | IIC_M_NOSTOP;
539 msgs[0].buf = ®addr;
541 msgs[1].slave = slaveaddr;
542 msgs[1].flags = IIC_M_RD;
543 msgs[1].len = buflen;
544 msgs[1].buf = buffer;
546 return (iicbus_transfer_excl(slavedev, msgs, nitems(msgs), waithow));
549 int iicdev_writeto(device_t slavedev, uint8_t regaddr, void *buffer,
550 uint16_t buflen, int waithow)
553 uint8_t local_buffer[32];
559 * Ideally, we would do two transfers back to back with no stop or start
560 * between them using an array of 2 iic_msgs; first we'd write the
561 * address byte using the IIC_M_NOSTOP flag, then we write the data
562 * using IIC_M_NOSTART, all in a single transfer. Unfortunately,
563 * several i2c hardware drivers don't support that (perhaps because the
564 * hardware itself can't support it). So instead we gather the
565 * scattered bytes into a single buffer here before writing them using a
566 * single iic_msg. This function is typically used to write a few bytes
567 * at a time, so we try to use a small local buffer on the stack, but
568 * fall back to allocating a temporary buffer when necessary.
571 bufsize = buflen + 1;
572 if (bufsize <= sizeof(local_buffer)) {
573 bufptr = local_buffer;
575 bufptr = malloc(bufsize, M_DEVBUF,
576 (waithow & IIC_WAIT) ? M_WAITOK : M_NOWAIT);
578 return (errno2iic(ENOMEM));
582 memcpy(&bufptr[1], buffer, buflen);
584 msg.slave = iicbus_get_addr(slavedev);
585 msg.flags = IIC_M_WR;
589 error = iicbus_transfer_excl(slavedev, &msg, 1, waithow);
591 if (bufptr != local_buffer)
592 free(bufptr, M_DEVBUF);