FreeBSD/Linux Kernel Cross Reference
sys/arm/xscale/ixp425/ixp425_iic.c

     /*
      * Copyright (c) 2006 Kevin Lo. 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 WASABI SYSTEMS, INC. ``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 WASABI SYSTEMS, INC
     * 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("$FreeBSD$");
    
    #include <sys/param.h>
    #include <sys/systm.h>
    #include <sys/kernel.h>
    #include <sys/module.h>
    #include <sys/bus.h>
    #include <sys/uio.h>
    
    #include <arm/xscale/ixp425/ixp425reg.h>
    #include <arm/xscale/ixp425/ixp425var.h>
    #include <arm/xscale/ixp425/ixdp425reg.h>
    
    #include <dev/iicbus/iiconf.h>
    #include <dev/iicbus/iicbus.h>
    
    #include "iicbb_if.h"
    
    #define I2C_DELAY       10
    
    /* bit clr/set shorthands */
    #define GPIO_CONF_CLR(sc, reg, mask)    \
            GPIO_CONF_WRITE_4(sc, reg, GPIO_CONF_READ_4(sc, reg) &~ (mask))
    #define GPIO_CONF_SET(sc, reg, mask)    \
            GPIO_CONF_WRITE_4(sc, reg, GPIO_CONF_READ_4(sc, reg) | (mask))
    
    struct ixpiic_softc {
            device_t                sc_dev;
            bus_space_tag_t         sc_iot;
            bus_space_handle_t      sc_gpio_ioh;
    
            device_t                iicbb;
    };
    
    static struct ixpiic_softc *ixpiic_sc = NULL;
    
    static int
    ixpiic_probe(device_t dev)
    {
            device_set_desc(dev, "IXP425 GPIO-Based I2C Interface");
            return (0);
    }
    
    static int
    ixpiic_attach(device_t dev)
    {
            struct ixpiic_softc *sc = device_get_softc(dev);
            struct ixp425_softc *sa = device_get_softc(device_get_parent(dev));
    
            ixpiic_sc = sc;
    
            sc->sc_dev = dev;
            sc->sc_iot = sa->sc_iot;
            sc->sc_gpio_ioh = sa->sc_gpio_ioh;
    
            GPIO_CONF_SET(sc, IXP425_GPIO_GPOER,
                    GPIO_I2C_SCL_BIT | GPIO_I2C_SDA_BIT);
            GPIO_CONF_CLR(sc, IXP425_GPIO_GPOUTR,
                    GPIO_I2C_SCL_BIT | GPIO_I2C_SDA_BIT);
    
            /* add generic bit-banging code */      
            if ((sc->iicbb = device_add_child(dev, "iicbb", -1)) == NULL)
                    device_printf(dev, "could not add iicbb\n");
    
            /* probe and attach the bit-banging code */
            device_probe_and_attach(sc->iicbb);
    
            return (0);
    }
    
    static int
    ixpiic_callback(device_t dev, int index, caddr_t *data)
    {
           return (0);
   }
   
   static int 
   ixpiic_getscl(device_t dev)
   {
           struct ixpiic_softc *sc = ixpiic_sc;
           uint32_t reg;
   
           GPIO_CONF_SET(sc, IXP425_GPIO_GPOER, GPIO_I2C_SCL_BIT);
   
           reg = GPIO_CONF_READ_4(sc, IXP425_GPIO_GPINR);
           return (reg & GPIO_I2C_SCL_BIT);
   }
   
   static int 
   ixpiic_getsda(device_t dev)
   {
           struct ixpiic_softc *sc = ixpiic_sc;
           uint32_t reg;
   
           GPIO_CONF_SET(sc, IXP425_GPIO_GPOER, GPIO_I2C_SDA_BIT);
   
           reg = GPIO_CONF_READ_4(sc, IXP425_GPIO_GPINR);
           return (reg & GPIO_I2C_SDA_BIT);
   }
   
   static void 
   ixpiic_setsda(device_t dev, char val)
   {
           struct ixpiic_softc *sc = ixpiic_sc;
   
           GPIO_CONF_CLR(sc, IXP425_GPIO_GPOUTR, GPIO_I2C_SDA_BIT);
           if (val)
                   GPIO_CONF_SET(sc, IXP425_GPIO_GPOER, GPIO_I2C_SDA_BIT);
           else
                   GPIO_CONF_CLR(sc, IXP425_GPIO_GPOER, GPIO_I2C_SDA_BIT);
           DELAY(I2C_DELAY);
   }
   
   static void 
   ixpiic_setscl(device_t dev, char val)
   {
           struct ixpiic_softc *sc = ixpiic_sc;
   
           GPIO_CONF_CLR(sc, IXP425_GPIO_GPOUTR, GPIO_I2C_SCL_BIT);
           if (val)
                   GPIO_CONF_SET(sc, IXP425_GPIO_GPOER, GPIO_I2C_SCL_BIT);
           else
                   GPIO_CONF_CLR(sc, IXP425_GPIO_GPOER, GPIO_I2C_SCL_BIT);
           DELAY(I2C_DELAY);
   }
   
   static int
   ixpiic_reset(device_t dev, u_char speed, u_char addr, u_char *oldaddr)
   {
           /* reset bus */
           ixpiic_setsda(dev, 1);
           ixpiic_setscl(dev, 1);
   
           return (IIC_ENOADDR);
   }
   
   static device_method_t ixpiic_methods[] = {
           /* device interface */
           DEVMETHOD(device_probe,         ixpiic_probe),
           DEVMETHOD(device_attach,        ixpiic_attach),
   
           /* iicbb interface */
           DEVMETHOD(iicbb_callback,       ixpiic_callback),
           DEVMETHOD(iicbb_setsda,         ixpiic_setsda),
           DEVMETHOD(iicbb_setscl,         ixpiic_setscl),
           DEVMETHOD(iicbb_getsda,         ixpiic_getsda),
           DEVMETHOD(iicbb_getscl,         ixpiic_getscl),
           DEVMETHOD(iicbb_reset,          ixpiic_reset),
   
           { 0, 0 }
   };
   
   static driver_t ixpiic_driver = {
           "ixpiic",
           ixpiic_methods,
           sizeof(struct ixpiic_softc),
   };
   static devclass_t ixpiic_devclass;
   
   DRIVER_MODULE(ixpiic, ixp, ixpiic_driver, ixpiic_devclass, 0, 0);

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