FreeBSD/Linux Kernel Cross Reference
sys/dev/iicbus/iicbus.c

     /*-
      * Copyright (c) 1998, 2001 Nicolas Souchu
      * 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("$FreeBSD$");
    
    /*
     * Autoconfiguration and support routines for the Philips serial I2C bus
     */
    
    #include <sys/param.h>
    #include <sys/systm.h>
    #include <sys/kernel.h>
    #include <sys/lock.h>
    #include <sys/malloc.h>
    #include <sys/module.h>
    #include <sys/mutex.h>
    #include <sys/bus.h> 
    
    #include <dev/iicbus/iiconf.h>
    #include <dev/iicbus/iicbus.h>
    
    #include "iicbus_if.h"
    
    /* See comments below for why auto-scanning is a bad idea. */
    #define SCAN_IICBUS 0
    
    static int
    iicbus_probe(device_t dev)
    {
    
            device_set_desc(dev, "Philips I2C bus");
    
            /* Allow other subclasses to override this driver. */
            return (BUS_PROBE_GENERIC);
    }
    
    #if SCAN_IICBUS
    static int 
    iic_probe_device(device_t dev, u_char addr)
    {
            int count;
            char byte;
    
            if ((addr & 1) == 0) {
                    /* is device writable? */
                    if (!iicbus_start(dev, (u_char)addr, 0)) {
                            iicbus_stop(dev);
                            return (1);
                    }
            } else {
                    /* is device readable? */
                    if (!iicbus_block_read(dev, (u_char)addr, &byte, 1, &count))
                            return (1);
            }
    
            return (0);
    }
    #endif
    
    /*
     * We add all the devices which we know about.
     * The generic attach routine will attach them if they are alive.
     */
    static int
    iicbus_attach(device_t dev)
    {
    #if SCAN_IICBUS
            unsigned char addr;
    #endif
            struct iicbus_softc *sc = IICBUS_SOFTC(dev);
    
            sc->dev = dev;
            mtx_init(&sc->lock, "iicbus", NULL, MTX_DEF);
            iicbus_reset(dev, IIC_FASTEST, 0, NULL);
    
           /* device probing is meaningless since the bus is supposed to be
            * hot-plug. Moreover, some I2C chips do not appreciate random
            * accesses like stop after start to fast, reads for less than
            * x bytes...
            */
   #if SCAN_IICBUS
           printf("Probing for devices on iicbus%d:", device_get_unit(dev));
   
           /* probe any devices */
           for (addr = 16; addr < 240; addr++) {
                   if (iic_probe_device(dev, (u_char)addr)) {
                           printf(" <%x>", addr);
                   }
           }
           printf("\n");
   #endif
           bus_generic_probe(dev);
           bus_enumerate_hinted_children(dev);
           bus_generic_attach(dev);
           return (0);
   }
     
   static int
   iicbus_detach(device_t dev)
   {
           struct iicbus_softc *sc = IICBUS_SOFTC(dev);
   
           iicbus_reset(dev, IIC_FASTEST, 0, NULL);
           bus_generic_detach(dev);
           mtx_destroy(&sc->lock);
           return (0);
   }
     
   static int
   iicbus_print_child(device_t dev, device_t child)
   {
           struct iicbus_ivar *devi = IICBUS_IVAR(child);
           int retval = 0;
   
           retval += bus_print_child_header(dev, child);
           if (devi->addr != 0)
                   retval += printf(" at addr %#x", devi->addr);
           retval += bus_print_child_footer(dev, child);
   
           return (retval);
   }
   
   static void
   iicbus_probe_nomatch(device_t bus, device_t child)
   {
           struct iicbus_ivar *devi = IICBUS_IVAR(child);
   
           device_printf(bus, "<unknown card>");
           printf(" at addr %#x\n", devi->addr);
           return;
   }
   
   static int
   iicbus_child_location_str(device_t bus, device_t child, char *buf,
       size_t buflen)
   {
           struct iicbus_ivar *devi = IICBUS_IVAR(child);
   
           snprintf(buf, buflen, "addr=%#x", devi->addr);
           return (0);
   }
   
   static int
   iicbus_child_pnpinfo_str(device_t bus, device_t child, char *buf,
       size_t buflen)
   {
           *buf = '\0';
           return (0);
   }
   
   static int
   iicbus_read_ivar(device_t bus, device_t child, int which, uintptr_t *result)
   {
           struct iicbus_ivar *devi = IICBUS_IVAR(child);
   
           switch (which) {
           default:
                   return (EINVAL);
           case IICBUS_IVAR_ADDR:
                   *result = devi->addr;
                   break;
           }
           return (0);
   }
   
   static device_t
   iicbus_add_child(device_t dev, u_int order, const char *name, int unit)
   {
           device_t child;
           struct iicbus_ivar *devi;
   
           child = device_add_child_ordered(dev, order, name, unit);
           if (child == NULL)
                   return (child);
           devi = malloc(sizeof(struct iicbus_ivar), M_DEVBUF, M_NOWAIT | M_ZERO);
           if (devi == NULL) {
                   device_delete_child(dev, child);
                   return (0);
           }
           device_set_ivars(child, devi);
           return (child);
   }
   
   static void
   iicbus_hinted_child(device_t bus, const char *dname, int dunit)
   {
           device_t child;
           struct iicbus_ivar *devi;
   
           child = BUS_ADD_CHILD(bus, 0, dname, dunit);
           devi = IICBUS_IVAR(child);
           resource_int_value(dname, dunit, "addr", &devi->addr);
   }
   
   int
   iicbus_generic_intr(device_t dev, int event, char *buf)
   {
   
           return (0);
   }
   
   int
   iicbus_null_callback(device_t dev, int index, caddr_t data)
   {
   
           return (0);
   }
   
   int
   iicbus_null_repeated_start(device_t dev, u_char addr)
   {
   
           return (IIC_ENOTSUPP);
   }
   
   static device_method_t iicbus_methods[] = {
           /* device interface */
           DEVMETHOD(device_probe,         iicbus_probe),
           DEVMETHOD(device_attach,        iicbus_attach),
           DEVMETHOD(device_detach,        iicbus_detach),
   
           /* bus interface */
           DEVMETHOD(bus_add_child,        iicbus_add_child),
           DEVMETHOD(bus_print_child,      iicbus_print_child),
           DEVMETHOD(bus_probe_nomatch,    iicbus_probe_nomatch),
           DEVMETHOD(bus_read_ivar,        iicbus_read_ivar),
           DEVMETHOD(bus_child_pnpinfo_str, iicbus_child_pnpinfo_str),
           DEVMETHOD(bus_child_location_str, iicbus_child_location_str),
           DEVMETHOD(bus_hinted_child,     iicbus_hinted_child),
   
           /* iicbus interface */
           DEVMETHOD(iicbus_transfer,      iicbus_transfer),
   
           DEVMETHOD_END
   };
   
   driver_t iicbus_driver = {
           "iicbus",
           iicbus_methods,
           sizeof(struct iicbus_softc),
   };
   
   devclass_t iicbus_devclass;
   
   MODULE_VERSION(iicbus, IICBUS_MODVER);
   DRIVER_MODULE(iicbus, iichb, iicbus_driver, iicbus_devclass, 0, 0);
   

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