FreeBSD/Linux Kernel Cross Reference
sys/dev/gpio/gpioiic.c

     /*-
      * Copyright (c) 2009 Oleksandr Tymoshenko <gonzo@freebsd.org>
      * Copyright (c) 2010 Luiz Otavio O Souza
      * All rights reserved.
      *
      * Redistribution and use in source and binary forms, with or without
      * modification, are permitted provided that the following conditions
      * are met:
      * 1. Redistributions of source code must retain the above copyright
     *    notice, this list of conditions and the following disclaimer.
     * 2. Redistributions in binary form must reproduce the above copyright
     *    notice, this list of conditions and the following disclaimer in the
     *    documentation and/or other materials provided with the distribution.
     *
     * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
     * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
     * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     * SUCH DAMAGE.
     */
    
    #include <sys/cdefs.h>
    __FBSDID("$FreeBSD: releng/9.0/sys/dev/gpio/gpioiic.c 213277 2010-09-29 20:53:33Z gonzo $");
    
    #include <sys/param.h>
    #include <sys/systm.h>
    #include <sys/bio.h>
    #include <sys/bus.h>
    #include <sys/conf.h>
    #include <sys/kernel.h>
    #include <sys/kthread.h>
    #include <sys/lock.h>
    #include <sys/malloc.h>
    #include <sys/module.h>
    #include <sys/mutex.h>
    
    #include <sys/gpio.h>
    #include "gpiobus_if.h"
    
    #include <dev/iicbus/iiconf.h>
    #include <dev/iicbus/iicbus.h>
    
    #include "iicbb_if.h"
    
    #define SCL_PIN         0       /* gpiobus mapped pin 6 */
    #define SDA_PIN         1       /* gpiobus mapped pin 7 */
    
    struct gpioiic_softc 
    {
            device_t        sc_dev;
            device_t        sc_busdev;
            struct mtx      sc_mtx;
            struct cdev     *sc_leddev;
    };
    
    static int gpioiic_probe(device_t);
    static int gpioiic_attach(device_t);
    
    /* iicbb interface */
    static void gpioiic_reset_bus(device_t);
    static int gpioiic_callback(device_t, int, caddr_t);
    static void gpioiic_setsda(device_t, int);
    static void gpioiic_setscl(device_t, int);
    static int gpioiic_getsda(device_t);
    static int gpioiic_getscl(device_t);
    static int gpioiic_reset(device_t, u_char, u_char, u_char *);
    
    
    static int
    gpioiic_probe(device_t dev)
    {
    
            device_set_desc(dev, "GPIO I2C bit-banging driver");
            return (0);
    }
    
    static int
    gpioiic_attach(device_t dev)
    {
            struct gpioiic_softc    *sc = device_get_softc(dev);
            device_t                bitbang;
    
            sc->sc_dev = dev;
            sc->sc_busdev = device_get_parent(dev);
    
            /* add generic bit-banging code */
            bitbang = device_add_child(dev, "iicbb", -1);
            device_probe_and_attach(bitbang);
    
            return (0);
    }
    
    /*
    * Reset bus by setting SDA first and then SCL. 
    * Must always be called with gpio bus locked.
    */
   static void
   gpioiic_reset_bus(device_t dev)
   {
           struct gpioiic_softc            *sc = device_get_softc(dev);
   
           GPIOBUS_PIN_SETFLAGS(sc->sc_busdev, sc->sc_dev, SDA_PIN,
               GPIO_PIN_INPUT);
           GPIOBUS_PIN_SETFLAGS(sc->sc_busdev, sc->sc_dev, SCL_PIN,
               GPIO_PIN_INPUT);
   }
   
   static int
   gpioiic_callback(device_t dev, int index, caddr_t data)
   {
           struct gpioiic_softc    *sc = device_get_softc(dev);
           int                     error = 0;
   
           switch (index) {
           case IIC_REQUEST_BUS:
                   GPIOBUS_LOCK_BUS(sc->sc_busdev);
                   GPIOBUS_ACQUIRE_BUS(sc->sc_busdev, sc->sc_dev);
                   GPIOBUS_UNLOCK_BUS(sc->sc_busdev);
                   break;
           case IIC_RELEASE_BUS:
                   GPIOBUS_LOCK_BUS(sc->sc_busdev);
                   GPIOBUS_RELEASE_BUS(sc->sc_busdev, sc->sc_dev);
                   GPIOBUS_UNLOCK_BUS(sc->sc_busdev);
                   break;
           default:
                   error = EINVAL;
           }
   
           return(error);
   }
   
   static void
   gpioiic_setsda(device_t dev, int val)
   {
           struct gpioiic_softc            *sc = device_get_softc(dev);
   
           GPIOBUS_LOCK_BUS(sc->sc_busdev);
           if (val == 0) {
                   GPIOBUS_PIN_SET(sc->sc_busdev, sc->sc_dev, SDA_PIN, 0);
                   GPIOBUS_PIN_SETFLAGS(sc->sc_busdev, sc->sc_dev, SDA_PIN,
                       GPIO_PIN_OUTPUT);
           } else {
                   GPIOBUS_PIN_SETFLAGS(sc->sc_busdev, sc->sc_dev, SDA_PIN,
                       GPIO_PIN_INPUT);
           }
           GPIOBUS_UNLOCK_BUS(sc->sc_busdev);
   }
   
   static void
   gpioiic_setscl(device_t dev, int val)
   {
           struct gpioiic_softc            *sc = device_get_softc(dev);
   
           GPIOBUS_LOCK_BUS(sc->sc_busdev);
           if (val == 0) {
                   GPIOBUS_PIN_SET(sc->sc_busdev, sc->sc_dev, SCL_PIN, 0);
                   GPIOBUS_PIN_SETFLAGS(sc->sc_busdev, sc->sc_dev, SCL_PIN,
                       GPIO_PIN_OUTPUT);
           } else {
                   GPIOBUS_PIN_SETFLAGS(sc->sc_busdev, sc->sc_dev, SCL_PIN,
                       GPIO_PIN_INPUT);
           }
           GPIOBUS_UNLOCK_BUS(sc->sc_busdev);
   }
   
   static int
   gpioiic_getscl(device_t dev)
   {
           struct gpioiic_softc            *sc = device_get_softc(dev);
           unsigned int                    val;
   
           GPIOBUS_LOCK_BUS(sc->sc_busdev);
           GPIOBUS_PIN_SETFLAGS(sc->sc_busdev, sc->sc_dev, SCL_PIN,
               GPIO_PIN_INPUT);
           GPIOBUS_PIN_GET(sc->sc_busdev, sc->sc_dev, SCL_PIN, &val);
           GPIOBUS_UNLOCK_BUS(sc->sc_busdev);
   
           return ((int)val);
   }
   
   static int
   gpioiic_getsda(device_t dev)
   {
           struct gpioiic_softc            *sc = device_get_softc(dev);
           unsigned int                    val;
   
           GPIOBUS_LOCK_BUS(sc->sc_busdev);
           GPIOBUS_PIN_SETFLAGS(sc->sc_busdev, sc->sc_dev, SDA_PIN,
               GPIO_PIN_INPUT);
           GPIOBUS_PIN_GET(sc->sc_busdev, sc->sc_dev, SDA_PIN, &val);
           GPIOBUS_UNLOCK_BUS(sc->sc_busdev);
   
           return ((int)val);
   }
   
   static int
   gpioiic_reset(device_t dev, u_char speed, u_char addr, u_char *oldaddr)
   {
           struct gpioiic_softc            *sc = device_get_softc(dev);
   
           GPIOBUS_LOCK_BUS(sc->sc_busdev);
           GPIOBUS_ACQUIRE_BUS(sc->sc_busdev, sc->sc_dev);
   
           gpioiic_reset_bus(sc->sc_dev);
   
           GPIOBUS_RELEASE_BUS(sc->sc_busdev, sc->sc_dev);
           GPIOBUS_UNLOCK_BUS(sc->sc_busdev);
   
           return (IIC_ENOADDR);
   }
   
   static devclass_t gpioiic_devclass;
   
   static device_method_t gpioiic_methods[] = {
           /* Device interface */
           DEVMETHOD(device_probe,         gpioiic_probe),
           DEVMETHOD(device_attach,        gpioiic_attach),
           DEVMETHOD(device_detach,        bus_generic_detach),
   
           /* iicbb interface */
           DEVMETHOD(iicbb_callback,       gpioiic_callback),
           DEVMETHOD(iicbb_setsda,         gpioiic_setsda),
           DEVMETHOD(iicbb_setscl,         gpioiic_setscl),
           DEVMETHOD(iicbb_getsda,         gpioiic_getsda),
           DEVMETHOD(iicbb_getscl,         gpioiic_getscl),
           DEVMETHOD(iicbb_reset,          gpioiic_reset),
   
           { 0, 0 }
   };
   
   static driver_t gpioiic_driver = {
           "gpioiic",
           gpioiic_methods,
           sizeof(struct gpioiic_softc),
   };
   
   DRIVER_MODULE(gpioiic, gpiobus, gpioiic_driver, gpioiic_devclass, 0, 0);
   DRIVER_MODULE(iicbb, gpioiic, iicbb_driver, iicbb_devclass, 0, 0);
   MODULE_DEPEND(gpioiic, iicbb, IICBB_MINVER, IICBB_PREFVER, IICBB_MAXVER);
   MODULE_DEPEND(gpioiic, gpiobus, 1, 1, 1);

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