ddd7699151
performance issues. * Access to the GPIO bus is already locked by requesting and releasing the bus - thus the lock isn't really needed for each GPIO pin change. * Don't lock and unlock the GPIO bus for -each- i2c access - the i2c bus code is already doing this by calling the upper layer callback to request/release the bus. This thus locks the bus for the entirety of the transaction. TODO: * Further verify that everything is correctly requesting/ releasing the GPIO bus. * Look at how to lock the GPIO pin configuration stuff, potentially by locking/unlocking the bus at the gpiobus layer.
244 lines
6.4 KiB
C
244 lines
6.4 KiB
C
/*-
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* Copyright (c) 2009 Oleksandr Tymoshenko <gonzo@freebsd.org>
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* Copyright (c) 2010 Luiz Otavio O Souza
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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/bio.h>
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#include <sys/bus.h>
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#include <sys/conf.h>
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#include <sys/kernel.h>
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#include <sys/kthread.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/gpio.h>
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#include "gpiobus_if.h"
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#include <dev/iicbus/iiconf.h>
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#include <dev/iicbus/iicbus.h>
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#include "iicbb_if.h"
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#define SCL_PIN_DEFAULT 0 /* default index of SCL pin on gpiobus */
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#define SDA_PIN_DEFAULT 1
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struct gpioiic_softc
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{
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device_t sc_dev;
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device_t sc_busdev;
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struct cdev *sc_leddev;
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int scl_pin;
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int sda_pin;
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};
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static int gpioiic_probe(device_t);
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static int gpioiic_attach(device_t);
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/* iicbb interface */
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static void gpioiic_reset_bus(device_t);
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static int gpioiic_callback(device_t, int, caddr_t);
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static void gpioiic_setsda(device_t, int);
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static void gpioiic_setscl(device_t, int);
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static int gpioiic_getsda(device_t);
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static int gpioiic_getscl(device_t);
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static int gpioiic_reset(device_t, u_char, u_char, u_char *);
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static int
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gpioiic_probe(device_t dev)
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{
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device_set_desc(dev, "GPIO I2C bit-banging driver");
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return (0);
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}
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static int
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gpioiic_attach(device_t dev)
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{
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struct gpioiic_softc *sc = device_get_softc(dev);
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device_t bitbang;
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sc->sc_dev = dev;
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sc->sc_busdev = device_get_parent(dev);
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if (resource_int_value(device_get_name(dev),
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device_get_unit(dev), "scl", &sc->scl_pin))
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sc->scl_pin = SCL_PIN_DEFAULT;
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if (resource_int_value(device_get_name(dev),
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device_get_unit(dev), "sda", &sc->sda_pin))
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sc->sda_pin = SDA_PIN_DEFAULT;
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/* add generic bit-banging code */
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bitbang = device_add_child(dev, "iicbb", -1);
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device_probe_and_attach(bitbang);
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return (0);
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}
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/*
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* Reset bus by setting SDA first and then SCL.
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* Must always be called with gpio bus locked.
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*/
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static void
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gpioiic_reset_bus(device_t dev)
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{
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struct gpioiic_softc *sc = device_get_softc(dev);
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GPIOBUS_PIN_SETFLAGS(sc->sc_busdev, sc->sc_dev, sc->sda_pin,
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GPIO_PIN_INPUT);
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GPIOBUS_PIN_SETFLAGS(sc->sc_busdev, sc->sc_dev, sc->scl_pin,
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GPIO_PIN_INPUT);
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}
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static int
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gpioiic_callback(device_t dev, int index, caddr_t data)
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{
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struct gpioiic_softc *sc = device_get_softc(dev);
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int error = 0;
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switch (index) {
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case IIC_REQUEST_BUS:
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GPIOBUS_LOCK_BUS(sc->sc_busdev);
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GPIOBUS_ACQUIRE_BUS(sc->sc_busdev, sc->sc_dev);
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GPIOBUS_UNLOCK_BUS(sc->sc_busdev);
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break;
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case IIC_RELEASE_BUS:
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GPIOBUS_LOCK_BUS(sc->sc_busdev);
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GPIOBUS_RELEASE_BUS(sc->sc_busdev, sc->sc_dev);
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GPIOBUS_UNLOCK_BUS(sc->sc_busdev);
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break;
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default:
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error = EINVAL;
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}
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return(error);
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}
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static void
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gpioiic_setsda(device_t dev, int val)
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{
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struct gpioiic_softc *sc = device_get_softc(dev);
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if (val == 0) {
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GPIOBUS_PIN_SET(sc->sc_busdev, sc->sc_dev, sc->sda_pin, 0);
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GPIOBUS_PIN_SETFLAGS(sc->sc_busdev, sc->sc_dev, sc->sda_pin,
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GPIO_PIN_OUTPUT);
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} else {
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GPIOBUS_PIN_SETFLAGS(sc->sc_busdev, sc->sc_dev, sc->sda_pin,
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GPIO_PIN_INPUT);
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}
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}
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static void
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gpioiic_setscl(device_t dev, int val)
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{
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struct gpioiic_softc *sc = device_get_softc(dev);
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if (val == 0) {
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GPIOBUS_PIN_SET(sc->sc_busdev, sc->sc_dev, sc->scl_pin, 0);
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GPIOBUS_PIN_SETFLAGS(sc->sc_busdev, sc->sc_dev, sc->scl_pin,
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GPIO_PIN_OUTPUT);
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} else {
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GPIOBUS_PIN_SETFLAGS(sc->sc_busdev, sc->sc_dev, sc->scl_pin,
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GPIO_PIN_INPUT);
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}
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}
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static int
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gpioiic_getscl(device_t dev)
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{
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struct gpioiic_softc *sc = device_get_softc(dev);
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unsigned int val;
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GPIOBUS_PIN_SETFLAGS(sc->sc_busdev, sc->sc_dev, sc->scl_pin,
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GPIO_PIN_INPUT);
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GPIOBUS_PIN_GET(sc->sc_busdev, sc->sc_dev, sc->scl_pin, &val);
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return ((int)val);
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}
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static int
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gpioiic_getsda(device_t dev)
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{
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struct gpioiic_softc *sc = device_get_softc(dev);
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unsigned int val;
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GPIOBUS_PIN_SETFLAGS(sc->sc_busdev, sc->sc_dev, sc->sda_pin,
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GPIO_PIN_INPUT);
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GPIOBUS_PIN_GET(sc->sc_busdev, sc->sc_dev, sc->sda_pin, &val);
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return ((int)val);
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}
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static int
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gpioiic_reset(device_t dev, u_char speed, u_char addr, u_char *oldaddr)
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{
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struct gpioiic_softc *sc = device_get_softc(dev);
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GPIOBUS_ACQUIRE_BUS(sc->sc_busdev, sc->sc_dev);
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gpioiic_reset_bus(sc->sc_dev);
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GPIOBUS_RELEASE_BUS(sc->sc_busdev, sc->sc_dev);
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return (IIC_ENOADDR);
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}
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static devclass_t gpioiic_devclass;
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static device_method_t gpioiic_methods[] = {
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/* Device interface */
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DEVMETHOD(device_probe, gpioiic_probe),
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DEVMETHOD(device_attach, gpioiic_attach),
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DEVMETHOD(device_detach, bus_generic_detach),
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/* iicbb interface */
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DEVMETHOD(iicbb_callback, gpioiic_callback),
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DEVMETHOD(iicbb_setsda, gpioiic_setsda),
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DEVMETHOD(iicbb_setscl, gpioiic_setscl),
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DEVMETHOD(iicbb_getsda, gpioiic_getsda),
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DEVMETHOD(iicbb_getscl, gpioiic_getscl),
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DEVMETHOD(iicbb_reset, gpioiic_reset),
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{ 0, 0 }
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};
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static driver_t gpioiic_driver = {
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"gpioiic",
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gpioiic_methods,
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sizeof(struct gpioiic_softc),
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};
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DRIVER_MODULE(gpioiic, gpiobus, gpioiic_driver, gpioiic_devclass, 0, 0);
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DRIVER_MODULE(iicbb, gpioiic, iicbb_driver, iicbb_devclass, 0, 0);
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MODULE_DEPEND(gpioiic, iicbb, IICBB_MINVER, IICBB_PREFVER, IICBB_MAXVER);
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MODULE_DEPEND(gpioiic, gpiobus, 1, 1, 1);
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