649b177fe3
Make it clearer what each one means in the comments that define them. IIC_BUSBSY was used in many places to mean two different things, either "someone else has reserved the bus so you have to wait until they're done" or "the signal level on the bus was not in the state I expected before/after issuing some command". Now IIC_BUSERR is used consistantly to refer to protocol/signaling errors, and IIC_BUSBSY refers to ownership/reservation of the bus.
486 lines
9.8 KiB
C
486 lines
9.8 KiB
C
/*-
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* Copyright (c) 1998 Nicolas Souchu, Marc Bouget
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* Copyright (c) 2004 Joerg Wunsch
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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/bus.h>
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#include <sys/lock.h>
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#include <sys/kernel.h>
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#include <sys/module.h>
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#include <sys/mutex.h>
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#include <sys/systm.h>
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#include <machine/bus.h>
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#include <machine/resource.h>
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#include <sys/rman.h>
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#include <dev/iicbus/iicbus.h>
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#include <dev/iicbus/iiconf.h>
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#include <dev/pcf/pcfvar.h>
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#include "iicbus_if.h"
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/* Not so official debugging option. */
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/* #define PCFDEBUG */
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static int pcf_wait_byte(struct pcf_softc *pcf);
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static int pcf_noack(struct pcf_softc *pcf, int timeout);
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static void pcf_stop_locked(struct pcf_softc *pcf);
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/*
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* Polling mode for master operations wait for a new
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* byte incoming or outgoing
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*/
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static int
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pcf_wait_byte(struct pcf_softc *sc)
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{
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int counter = TIMEOUT;
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PCF_ASSERT_LOCKED(sc);
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while (counter--) {
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if ((pcf_get_S1(sc) & PIN) == 0)
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return (0);
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}
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#ifdef PCFDEBUG
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printf("pcf: timeout!\n");
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#endif
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return (IIC_ETIMEOUT);
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}
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static void
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pcf_stop_locked(struct pcf_softc *sc)
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{
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PCF_ASSERT_LOCKED(sc);
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#ifdef PCFDEBUG
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device_printf(dev, " >> stop\n");
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#endif
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/*
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* Send STOP condition iff the START condition was previously sent.
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* STOP is sent only once even if an iicbus_stop() is called after
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* an iicbus_read()... see pcf_read(): the PCF needs to send the stop
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* before the last char is read.
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*/
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if (sc->pcf_started) {
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/* set stop condition and enable IT */
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pcf_set_S1(sc, PIN|ESO|ENI|STO|ACK);
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sc->pcf_started = 0;
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}
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}
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static int
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pcf_noack(struct pcf_softc *sc, int timeout)
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{
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int noack;
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int k = timeout/10;
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PCF_ASSERT_LOCKED(sc);
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do {
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noack = pcf_get_S1(sc) & LRB;
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if (!noack)
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break;
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DELAY(10); /* XXX wait 10 us */
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} while (k--);
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return (noack);
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}
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int
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pcf_repeated_start(device_t dev, u_char slave, int timeout)
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{
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struct pcf_softc *sc = DEVTOSOFTC(dev);
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int error = 0;
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PCF_LOCK(sc);
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#ifdef PCFDEBUG
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device_printf(dev, " >> repeated start for slave %#x\n",
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(unsigned)slave);
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#endif
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/* repeated start */
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pcf_set_S1(sc, ESO|STA|STO|ACK);
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/* set slave address to PCF. Last bit (LSB) must be set correctly
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* according to transfer direction */
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pcf_set_S0(sc, slave);
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/* wait for address sent, polling */
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if ((error = pcf_wait_byte(sc)))
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goto error;
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/* check for ack */
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if (pcf_noack(sc, timeout)) {
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error = IIC_ENOACK;
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#ifdef PCFDEBUG
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printf("pcf: no ack on repeated_start!\n");
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#endif
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goto error;
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}
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PCF_UNLOCK(sc);
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return (0);
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error:
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pcf_stop_locked(sc);
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PCF_UNLOCK(sc);
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return (error);
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}
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int
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pcf_start(device_t dev, u_char slave, int timeout)
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{
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struct pcf_softc *sc = DEVTOSOFTC(dev);
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int error = 0;
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PCF_LOCK(sc);
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#ifdef PCFDEBUG
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device_printf(dev, " >> start for slave %#x\n", (unsigned)slave);
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#endif
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if ((pcf_get_S1(sc) & nBB) == 0) {
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#ifdef PCFDEBUG
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printf("pcf: busy!\n");
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#endif
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PCF_UNLOCK(sc);
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return (IIC_EBUSERR);
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}
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/* set slave address to PCF. Last bit (LSB) must be set correctly
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* according to transfer direction */
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pcf_set_S0(sc, slave);
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/* START only */
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pcf_set_S1(sc, PIN|ESO|STA|ACK);
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sc->pcf_started = 1;
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/* wait for address sent, polling */
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if ((error = pcf_wait_byte(sc)))
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goto error;
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/* check for ACK */
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if (pcf_noack(sc, timeout)) {
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error = IIC_ENOACK;
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#ifdef PCFDEBUG
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printf("pcf: no ack on start!\n");
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#endif
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goto error;
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}
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PCF_UNLOCK(sc);
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return (0);
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error:
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pcf_stop_locked(sc);
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PCF_UNLOCK(sc);
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return (error);
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}
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int
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pcf_stop(device_t dev)
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{
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struct pcf_softc *sc = DEVTOSOFTC(dev);
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#ifdef PCFDEBUG
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device_printf(dev, " >> stop\n");
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#endif
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PCF_LOCK(sc);
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pcf_stop_locked(sc);
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PCF_UNLOCK(sc);
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return (0);
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}
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void
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pcf_intr(void *arg)
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{
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struct pcf_softc *sc = arg;
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char data, status, addr;
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char error = 0;
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PCF_LOCK(sc);
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status = pcf_get_S1(sc);
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if (status & PIN) {
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printf("pcf: spurious interrupt, status=0x%x\n",
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status & 0xff);
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goto error;
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}
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if (status & LAB)
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printf("pcf: bus arbitration lost!\n");
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if (status & BER) {
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error = IIC_EBUSERR;
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iicbus_intr(sc->iicbus, INTR_ERROR, &error);
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goto error;
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}
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do {
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status = pcf_get_S1(sc);
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switch(sc->pcf_slave_mode) {
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case SLAVE_TRANSMITTER:
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if (status & LRB) {
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/* ack interrupt line */
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dummy_write(sc);
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/* no ack, don't send anymore */
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sc->pcf_slave_mode = SLAVE_RECEIVER;
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iicbus_intr(sc->iicbus, INTR_NOACK, NULL);
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break;
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}
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/* get data from upper code */
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iicbus_intr(sc->iicbus, INTR_TRANSMIT, &data);
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pcf_set_S0(sc, data);
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break;
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case SLAVE_RECEIVER:
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if (status & AAS) {
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addr = pcf_get_S0(sc);
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if (status & AD0)
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iicbus_intr(sc->iicbus, INTR_GENERAL, &addr);
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else
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iicbus_intr(sc->iicbus, INTR_START, &addr);
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if (addr & LSB) {
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sc->pcf_slave_mode = SLAVE_TRANSMITTER;
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/* get the first char from upper code */
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iicbus_intr(sc->iicbus, INTR_TRANSMIT, &data);
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/* send first data byte */
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pcf_set_S0(sc, data);
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}
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break;
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}
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/* stop condition received? */
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if (status & STS) {
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/* ack interrupt line */
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dummy_read(sc);
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/* emulate intr stop condition */
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iicbus_intr(sc->iicbus, INTR_STOP, NULL);
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} else {
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/* get data, ack interrupt line */
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data = pcf_get_S0(sc);
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/* deliver the character */
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iicbus_intr(sc->iicbus, INTR_RECEIVE, &data);
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}
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break;
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default:
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panic("%s: unknown slave mode (%d)!", __func__,
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sc->pcf_slave_mode);
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}
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} while ((pcf_get_S1(sc) & PIN) == 0);
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PCF_UNLOCK(sc);
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return;
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error:
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/* unknown event on bus...reset PCF */
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pcf_set_S1(sc, PIN|ESO|ENI|ACK);
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sc->pcf_slave_mode = SLAVE_RECEIVER;
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PCF_UNLOCK(sc);
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return;
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}
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int
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pcf_rst_card(device_t dev, u_char speed, u_char addr, u_char *oldaddr)
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{
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struct pcf_softc *sc = DEVTOSOFTC(dev);
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PCF_LOCK(sc);
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if (oldaddr)
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*oldaddr = sc->pcf_addr;
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/* retrieve own address from bus level */
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if (!addr)
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sc->pcf_addr = PCF_DEFAULT_ADDR;
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else
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sc->pcf_addr = addr;
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pcf_set_S1(sc, PIN); /* initialize S1 */
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/* own address S'O<>0 */
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pcf_set_S0(sc, sc->pcf_addr >> 1);
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/* select clock register */
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pcf_set_S1(sc, PIN|ES1);
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/* select bus speed : 18=90kb, 19=45kb, 1A=11kb, 1B=1.5kb */
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switch (speed) {
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case IIC_SLOW:
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pcf_set_S0(sc, 0x1b); /* XXX Sun uses 0x1f */
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break;
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case IIC_FAST:
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pcf_set_S0(sc, 0x19); /* XXX Sun: 0x1d */
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break;
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case IIC_UNKNOWN:
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case IIC_FASTEST:
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default:
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pcf_set_S0(sc, 0x18); /* XXX Sun: 0x1c */
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break;
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}
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/* set bus on, ack=yes, INT=yes */
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pcf_set_S1(sc, PIN|ESO|ENI|ACK);
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sc->pcf_slave_mode = SLAVE_RECEIVER;
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PCF_UNLOCK(sc);
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return (0);
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}
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int
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pcf_write(device_t dev, const char *buf, int len, int *sent, int timeout /* us */)
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{
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struct pcf_softc *sc = DEVTOSOFTC(dev);
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int bytes, error = 0;
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#ifdef PCFDEBUG
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device_printf(dev, " >> writing %d bytes: %#x%s\n", len,
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(unsigned)buf[0], len > 1? "...": "");
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#endif
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bytes = 0;
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PCF_LOCK(sc);
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while (len) {
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pcf_set_S0(sc, *buf++);
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/* wait for the byte to be send */
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if ((error = pcf_wait_byte(sc)))
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goto error;
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/* check if ack received */
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if (pcf_noack(sc, timeout)) {
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error = IIC_ENOACK;
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goto error;
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}
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len --;
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bytes ++;
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}
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error:
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*sent = bytes;
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PCF_UNLOCK(sc);
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#ifdef PCFDEBUG
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device_printf(dev, " >> %d bytes written (%d)\n", bytes, error);
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#endif
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return (error);
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}
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int
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pcf_read(device_t dev, char *buf, int len, int *read, int last,
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int delay /* us */)
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{
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struct pcf_softc *sc = DEVTOSOFTC(dev);
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int bytes, error = 0;
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#ifdef PCFDEBUG
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char *obuf = buf;
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device_printf(dev, " << reading %d bytes\n", len);
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#endif
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PCF_LOCK(sc);
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/* trig the bus to get the first data byte in S0 */
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if (len) {
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if (len == 1 && last)
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/* just one byte to read */
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pcf_set_S1(sc, ESO); /* no ack */
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dummy_read(sc);
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}
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bytes = 0;
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while (len) {
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/* XXX delay needed here */
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/* wait for trigged byte */
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if ((error = pcf_wait_byte(sc))) {
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pcf_stop_locked(sc);
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goto error;
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}
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if (len == 1 && last)
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/* ok, last data byte already in S0, no I2C activity
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* on next pcf_get_S0() */
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pcf_stop_locked(sc);
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else if (len == 2 && last)
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/* next trigged byte with no ack */
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pcf_set_S1(sc, ESO);
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/* receive byte, trig next byte */
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*buf++ = pcf_get_S0(sc);
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len --;
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bytes ++;
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};
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error:
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*read = bytes;
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PCF_UNLOCK(sc);
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#ifdef PCFDEBUG
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device_printf(dev, " << %d bytes read (%d): %#x%s\n", bytes, error,
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(unsigned)obuf[0], bytes > 1? "...": "");
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#endif
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return (error);
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}
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DRIVER_MODULE(iicbus, pcf, iicbus_driver, iicbus_devclass, 0, 0);
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MODULE_DEPEND(pcf, iicbus, PCF_MINVER, PCF_PREFVER, PCF_MAXVER);
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MODULE_VERSION(pcf, PCF_MODVER);
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