7ec74c580d
on i2c devices, where the "register" can be any length. Many (perhaps most) common i2c devices are organized as a collection of (usually 1-byte-wide) registers, and are accessed by first writing a 1-byte register index/offset number, then by reading or writing the data. Generally there is an auto-increment feature so the when multiple bytes are read or written, multiple contiguous registers are accessed. Most existing slave device drivers allocate an array of iic_msg structures, fill in all the transfer info, and invoke iicbus_transfer(). These new functions commonize all that and reduce register access to a simple call with a few arguments.
525 lines
12 KiB
C
525 lines
12 KiB
C
/*-
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* Copyright (c) 1998 Nicolas Souchu
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/lock.h>
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#include <sys/malloc.h>
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#include <sys/module.h>
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#include <sys/mutex.h>
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#include <sys/bus.h>
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#include <dev/iicbus/iiconf.h>
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#include <dev/iicbus/iicbus.h>
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#include "iicbus_if.h"
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/*
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* Translate IIC_Exxxxx status values to vaguely-equivelent errno values.
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*/
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int
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iic2errno(int iic_status)
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{
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switch (iic_status) {
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case IIC_NOERR: return (0);
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case IIC_EBUSERR: return (EALREADY);
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case IIC_ENOACK: return (EIO);
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case IIC_ETIMEOUT: return (ETIMEDOUT);
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case IIC_EBUSBSY: return (EWOULDBLOCK);
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case IIC_ESTATUS: return (EPROTO);
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case IIC_EUNDERFLOW: return (EIO);
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case IIC_EOVERFLOW: return (EOVERFLOW);
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case IIC_ENOTSUPP: return (EOPNOTSUPP);
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case IIC_ENOADDR: return (EADDRNOTAVAIL);
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case IIC_ERESOURCE: return (ENOMEM);
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default: return (EIO);
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}
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}
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/*
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* iicbus_intr()
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*/
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void
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iicbus_intr(device_t bus, int event, char *buf)
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{
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struct iicbus_softc *sc = (struct iicbus_softc *)device_get_softc(bus);
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/* call owner's intr routine */
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if (sc->owner)
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IICBUS_INTR(sc->owner, event, buf);
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return;
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}
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static int
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iicbus_poll(struct iicbus_softc *sc, int how)
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{
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int error;
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IICBUS_ASSERT_LOCKED(sc);
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switch (how) {
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case IIC_WAIT | IIC_INTR:
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error = mtx_sleep(sc, &sc->lock, IICPRI|PCATCH, "iicreq", 0);
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break;
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case IIC_WAIT | IIC_NOINTR:
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error = mtx_sleep(sc, &sc->lock, IICPRI, "iicreq", 0);
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break;
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default:
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return (IIC_EBUSBSY);
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}
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return (error);
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}
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/*
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* iicbus_request_bus()
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*
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* Allocate the device to perform transfers.
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*
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* how : IIC_WAIT or IIC_DONTWAIT
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*/
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int
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iicbus_request_bus(device_t bus, device_t dev, int how)
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{
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struct iicbus_softc *sc = (struct iicbus_softc *)device_get_softc(bus);
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int error = 0;
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IICBUS_LOCK(sc);
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while ((error == 0) && (sc->owner != NULL))
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error = iicbus_poll(sc, how);
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if (error == 0) {
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sc->owner = dev;
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/*
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* Drop the lock around the call to the bus driver.
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* This call should be allowed to sleep in the IIC_WAIT case.
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* Drivers might also need to grab locks that would cause LOR
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* if our lock is held.
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*/
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IICBUS_UNLOCK(sc);
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/* Ask the underlying layers if the request is ok */
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error = IICBUS_CALLBACK(device_get_parent(bus),
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IIC_REQUEST_BUS, (caddr_t)&how);
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IICBUS_LOCK(sc);
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if (error != 0) {
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sc->owner = NULL;
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wakeup_one(sc);
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}
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}
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IICBUS_UNLOCK(sc);
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return (error);
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}
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/*
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* iicbus_release_bus()
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*
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* Release the device allocated with iicbus_request_dev()
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*/
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int
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iicbus_release_bus(device_t bus, device_t dev)
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{
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struct iicbus_softc *sc = (struct iicbus_softc *)device_get_softc(bus);
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int error;
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IICBUS_LOCK(sc);
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if (sc->owner != dev) {
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IICBUS_UNLOCK(sc);
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return (IIC_EBUSBSY);
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}
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/*
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* Drop the lock around the call to the bus driver.
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* This call should be allowed to sleep in the IIC_WAIT case.
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* Drivers might also need to grab locks that would cause LOR
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* if our lock is held.
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*/
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IICBUS_UNLOCK(sc);
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/* Ask the underlying layers if the release is ok */
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error = IICBUS_CALLBACK(device_get_parent(bus), IIC_RELEASE_BUS, NULL);
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if (error == 0) {
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IICBUS_LOCK(sc);
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sc->owner = NULL;
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/* wakeup a waiting thread */
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wakeup_one(sc);
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IICBUS_UNLOCK(sc);
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}
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return (error);
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}
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/*
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* iicbus_started()
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*
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* Test if the iicbus is started by the controller
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*/
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int
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iicbus_started(device_t bus)
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{
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struct iicbus_softc *sc = (struct iicbus_softc *)device_get_softc(bus);
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return (sc->started);
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}
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/*
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* iicbus_start()
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*
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* Send start condition to the slave addressed by 'slave'
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*/
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int
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iicbus_start(device_t bus, u_char slave, int timeout)
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{
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struct iicbus_softc *sc = (struct iicbus_softc *)device_get_softc(bus);
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int error = 0;
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if (sc->started)
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return (IIC_ESTATUS); /* protocol error, bus already started */
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if (!(error = IICBUS_START(device_get_parent(bus), slave, timeout)))
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sc->started = slave;
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else
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sc->started = 0;
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return (error);
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}
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/*
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* iicbus_repeated_start()
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*
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* Send start condition to the slave addressed by 'slave'
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*/
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int
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iicbus_repeated_start(device_t bus, u_char slave, int timeout)
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{
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struct iicbus_softc *sc = (struct iicbus_softc *)device_get_softc(bus);
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int error = 0;
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if (!sc->started)
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return (IIC_ESTATUS); /* protocol error, bus not started */
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if (!(error = IICBUS_REPEATED_START(device_get_parent(bus), slave, timeout)))
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sc->started = slave;
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else
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sc->started = 0;
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return (error);
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}
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/*
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* iicbus_stop()
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*
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* Send stop condition to the bus
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*/
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int
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iicbus_stop(device_t bus)
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{
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struct iicbus_softc *sc = (struct iicbus_softc *)device_get_softc(bus);
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int error = 0;
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if (!sc->started)
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return (IIC_ESTATUS); /* protocol error, bus not started */
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error = IICBUS_STOP(device_get_parent(bus));
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/* refuse any further access */
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sc->started = 0;
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return (error);
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}
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/*
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* iicbus_write()
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*
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* Write a block of data to the slave previously started by
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* iicbus_start() call
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*/
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int
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iicbus_write(device_t bus, const char *buf, int len, int *sent, int timeout)
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{
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struct iicbus_softc *sc = (struct iicbus_softc *)device_get_softc(bus);
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/* a slave must have been started for writing */
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if (sc->started == 0 || (sc->strict != 0 && (sc->started & LSB) != 0))
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return (IIC_ESTATUS);
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return (IICBUS_WRITE(device_get_parent(bus), buf, len, sent, timeout));
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}
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/*
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* iicbus_read()
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*
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* Read a block of data from the slave previously started by
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* iicbus_read() call
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*/
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int
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iicbus_read(device_t bus, char *buf, int len, int *read, int last, int delay)
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{
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struct iicbus_softc *sc = (struct iicbus_softc *)device_get_softc(bus);
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/* a slave must have been started for reading */
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if (sc->started == 0 || (sc->strict != 0 && (sc->started & LSB) == 0))
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return (IIC_ESTATUS);
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return (IICBUS_READ(device_get_parent(bus), buf, len, read, last, delay));
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}
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/*
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* iicbus_write_byte()
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*
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* Write a byte to the slave previously started by iicbus_start() call
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*/
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int
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iicbus_write_byte(device_t bus, char byte, int timeout)
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{
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struct iicbus_softc *sc = device_get_softc(bus);
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char data = byte;
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int sent;
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/* a slave must have been started for writing */
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if (sc->started == 0 || (sc->strict != 0 && (sc->started & LSB) != 0))
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return (IIC_ESTATUS);
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return (iicbus_write(bus, &data, 1, &sent, timeout));
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}
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/*
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* iicbus_read_byte()
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*
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* Read a byte from the slave previously started by iicbus_start() call
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*/
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int
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iicbus_read_byte(device_t bus, char *byte, int timeout)
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{
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struct iicbus_softc *sc = device_get_softc(bus);
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int read;
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/* a slave must have been started for reading */
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if (sc->started == 0 || (sc->strict != 0 && (sc->started & LSB) == 0))
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return (IIC_ESTATUS);
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return (iicbus_read(bus, byte, 1, &read, IIC_LAST_READ, timeout));
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}
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/*
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* iicbus_block_write()
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*
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* Write a block of data to slave ; start/stop protocol managed
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*/
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int
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iicbus_block_write(device_t bus, u_char slave, char *buf, int len, int *sent)
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{
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u_char addr = slave & ~LSB;
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int error;
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if ((error = iicbus_start(bus, addr, 0)))
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return (error);
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error = iicbus_write(bus, buf, len, sent, 0);
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iicbus_stop(bus);
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return (error);
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}
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/*
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* iicbus_block_read()
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*
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* Read a block of data from slave ; start/stop protocol managed
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*/
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int
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iicbus_block_read(device_t bus, u_char slave, char *buf, int len, int *read)
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{
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u_char addr = slave | LSB;
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int error;
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if ((error = iicbus_start(bus, addr, 0)))
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return (error);
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error = iicbus_read(bus, buf, len, read, IIC_LAST_READ, 0);
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iicbus_stop(bus);
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return (error);
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}
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/*
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* iicbus_transfer()
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*
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* Do an aribtrary number of transfers on the iicbus. We pass these
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* raw requests to the bridge driver. If the bridge driver supports
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* them directly, then it manages all the details. If not, it can use
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* the helper function iicbus_transfer_gen() which will do the
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* transfers at a low level.
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*
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* Pointers passed in as part of iic_msg must be kernel pointers.
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* Callers that have user addresses to manage must do so on their own.
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*/
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int
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iicbus_transfer(device_t bus, struct iic_msg *msgs, uint32_t nmsgs)
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{
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return (IICBUS_TRANSFER(device_get_parent(bus), msgs, nmsgs));
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}
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int
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iicbus_transfer_excl(device_t dev, struct iic_msg *msgs, uint32_t nmsgs,
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int how)
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{
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device_t bus;
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int error;
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bus = device_get_parent(dev);
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error = iicbus_request_bus(bus, dev, how);
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if (error == 0)
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error = IICBUS_TRANSFER(bus, msgs, nmsgs);
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iicbus_release_bus(bus, dev);
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return (error);
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}
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/*
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* Generic version of iicbus_transfer that calls the appropriate
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* routines to accomplish this. See note above about acceptable
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* buffer addresses.
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*/
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int
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iicbus_transfer_gen(device_t dev, struct iic_msg *msgs, uint32_t nmsgs)
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{
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int i, error, lenread, lenwrote, nkid, rpstart, addr;
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device_t *children, bus;
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bool nostop, started;
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if ((error = device_get_children(dev, &children, &nkid)) != 0)
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return (IIC_ERESOURCE);
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if (nkid != 1) {
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free(children, M_TEMP);
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return (IIC_ENOTSUPP);
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}
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bus = children[0];
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rpstart = 0;
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free(children, M_TEMP);
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nostop = iicbus_get_nostop(dev);
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started = false;
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for (i = 0, error = 0; i < nmsgs && error == 0; i++) {
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addr = msgs[i].slave;
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if (msgs[i].flags & IIC_M_RD)
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addr |= LSB;
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else
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addr &= ~LSB;
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if (!(msgs[i].flags & IIC_M_NOSTART)) {
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if (rpstart)
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error = iicbus_repeated_start(bus, addr, 0);
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else
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error = iicbus_start(bus, addr, 0);
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if (error != 0)
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break;
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started = true;
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}
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if (msgs[i].flags & IIC_M_RD)
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error = iicbus_read(bus, msgs[i].buf, msgs[i].len,
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&lenread, IIC_LAST_READ, 0);
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else
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error = iicbus_write(bus, msgs[i].buf, msgs[i].len,
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&lenwrote, 0);
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if (error != 0)
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break;
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if ((msgs[i].flags & IIC_M_NOSTOP) != 0 ||
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(nostop && i + 1 < nmsgs)) {
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rpstart = 1; /* Next message gets repeated start */
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} else {
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rpstart = 0;
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iicbus_stop(bus);
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}
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}
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if (error != 0 && started)
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iicbus_stop(bus);
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return (error);
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}
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int
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iicdev_readfrom(device_t slavedev, uint8_t regaddr, void *buffer,
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uint16_t buflen, int waithow)
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{
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struct iic_msg msgs[2];
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uint8_t slaveaddr;
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/*
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* Two transfers back to back with a repeat-start between them; first we
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* write the address-within-device, then we read from the device.
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*/
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slaveaddr = iicbus_get_addr(slavedev);
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msgs[0].slave = slaveaddr;
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msgs[0].flags = IIC_M_WR | IIC_M_NOSTOP;
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msgs[0].len = 1;
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msgs[0].buf = ®addr;
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msgs[1].slave = slaveaddr;
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msgs[1].flags = IIC_M_RD;
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msgs[1].len = buflen;
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msgs[1].buf = buffer;
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return (iicbus_transfer_excl(slavedev, msgs, nitems(msgs), waithow));
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}
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int iicdev_writeto(device_t slavedev, uint8_t regaddr, void *buffer,
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uint16_t buflen, int waithow)
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{
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struct iic_msg msgs[2];
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uint8_t slaveaddr;
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/*
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* Two transfers back to back with no stop or start between them; first
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* we write the address then we write the data to that address, all in a
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* single transfer from two scattered buffers.
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*/
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slaveaddr = iicbus_get_addr(slavedev);
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msgs[0].slave = slaveaddr;
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msgs[0].flags = IIC_M_WR | IIC_M_NOSTOP;
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msgs[0].len = 1;
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msgs[0].buf = ®addr;
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msgs[1].slave = slaveaddr;
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msgs[1].flags = IIC_M_WR | IIC_M_NOSTART;
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msgs[1].len = buflen;
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msgs[1].buf = buffer;
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return (iicbus_transfer_excl(slavedev, msgs, nitems(msgs), waithow));
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}
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