9d35acacd3
hold the gpiobus lock between the gpio calls. gpiobus_acquire_lock() now accepts a third parameter which tells gpiobus what to do when the bus is already busy. When GPIOBUS_WAIT wait is used, the calling thread will be put to sleep until the bus became free. With GPIOBUS_DONTWAIT the calling thread will receive EWOULDBLOCK right away and then it can act upon. This fixes the gpioiic(4) locking issues that arises when doing multiple concurrent access on the bus.
288 lines
7.3 KiB
C
288 lines
7.3 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 "opt_platform.h"
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#include <sys/param.h>
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#include <sys/systm.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/module.h>
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#include <sys/gpio.h>
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#include "gpiobus_if.h"
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#ifdef FDT
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#include <dev/ofw/ofw_bus.h>
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#include <dev/ofw/ofw_bus_subr.h>
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#include <dev/fdt/fdt_common.h>
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#endif
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#include <dev/gpio/gpiobusvar.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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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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#ifdef FDT
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if (!ofw_bus_is_compatible(dev, "gpioiic"))
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return (ENXIO);
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#endif
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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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device_t bitbang;
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#ifdef FDT
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phandle_t node;
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pcell_t pin;
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#endif
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struct gpiobus_ivar *devi;
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struct gpioiic_softc *sc;
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sc = device_get_softc(dev);
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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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#ifdef FDT
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if ((node = ofw_bus_get_node(dev)) == -1)
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return (ENXIO);
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if (OF_getencprop(node, "scl", &pin, sizeof(pin)) > 0)
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sc->scl_pin = (int)pin;
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if (OF_getencprop(node, "sda", &pin, sizeof(pin)) > 0)
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sc->sda_pin = (int)pin;
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#endif
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if (sc->scl_pin < 0 || sc->scl_pin > 1)
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sc->scl_pin = SCL_PIN_DEFAULT;
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if (sc->sda_pin < 0 || sc->sda_pin > 1)
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sc->sda_pin = SDA_PIN_DEFAULT;
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devi = GPIOBUS_IVAR(dev);
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device_printf(dev, "SCL pin: %d, SDA pin: %d\n",
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devi->pins[sc->scl_pin], devi->pins[sc->sda_pin]);
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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, how;
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how = GPIOBUS_DONTWAIT;
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if (data != NULL && (int)*data == IIC_WAIT)
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how = GPIOBUS_WAIT;
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error = 0;
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switch (index) {
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case IIC_REQUEST_BUS:
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error = GPIOBUS_ACQUIRE_BUS(sc->sc_busdev, sc->sc_dev, how);
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break;
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case IIC_RELEASE_BUS:
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GPIOBUS_RELEASE_BUS(sc->sc_busdev, sc->sc_dev);
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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;
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sc = device_get_softc(dev);
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gpioiic_reset_bus(sc->sc_dev);
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return (IIC_ENOADDR);
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}
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#ifdef FDT
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static phandle_t
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gpioiic_get_node(device_t bus, device_t dev)
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{
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/* We only have one child, the iicbb, which needs our own node. */
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return (ofw_bus_get_node(bus));
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}
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#endif
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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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#ifdef FDT
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/* OFW bus interface */
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DEVMETHOD(ofw_bus_get_node, gpioiic_get_node),
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#endif
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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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