sys/bus/iicbus/iicbus.c

   1 /*-
   2  * Copyright (c) 1998, 2001 Nicolas Souchu
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  *
  14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  24  * SUCH DAMAGE.
  25  *
  26  * $FreeBSD: src/sys/dev/iicbus/iicbus.c,v 1.29 2009/02/10 22:50:23 imp Exp $
  27  */
  28
  29 /*
  30  * Autoconfiguration and support routines for the Philips serial I2C bus
  31  */
  32
  33 #include <sys/param.h>
  34 #include <sys/systm.h>
  35 #include <sys/kernel.h>
  36 #include <sys/module.h>
  37 #include <sys/bus.h>
  38
  39 #include <bus/iicbus/iiconf.h>
  40 #include <bus/iicbus/iicbus.h>
  41
  42 #include "iicbus_if.h"
  43
  44 #define DEVTOIICBUS(dev) ((struct iicbus_device*)device_get_ivars(dev))
  45
  46 devclass_t iicbus_devclass;
  47
  48 /* See comments below for why auto-scanning is a bad idea. */
  49 #define SCAN_IICBUS 0
  50
  51 /*
  52  * Device methods
  53  */
  54 static int iicbus_probe(device_t);
  55 static int iicbus_attach(device_t);
  56 static int iicbus_detach(device_t);
  57 static int iicbus_add_child(device_t dev, int order, const char *name, int unit);
  58
  59 static device_method_t iicbus_methods[] = {
  60         /* device interface */
  61         DEVMETHOD(device_probe,         iicbus_probe),
  62         DEVMETHOD(device_attach,        iicbus_attach),
  63         DEVMETHOD(device_detach,        iicbus_detach),
  64
  65         /* bus interface */
  66         DEVMETHOD(bus_add_child,        iicbus_add_child),
  67         DEVMETHOD(bus_driver_added,     bus_generic_driver_added),
  68         DEVMETHOD(bus_print_child,      bus_generic_print_child),
  69
  70         DEVMETHOD(iicbus_transfer,      iicbus_transfer_gen),
  71
  72         DEVMETHOD_END
  73 };
  74
  75 driver_t iicbus_driver = {
  76         "iicbus",
  77         iicbus_methods,
  78         sizeof(struct iicbus_softc),
  79 };
  80
  81 static int
  82 iicbus_probe(device_t dev)
  83 {
  84
  85         device_set_desc(dev, "Philips I2C bus");
  86
  87         /* Allow other subclasses to override this driver. */
  88         return (BUS_PROBE_GENERIC);
  89 }
  90
  91 #if SCAN_IICBUS
  92 static int
  93 iic_probe_device(device_t dev, u_char addr)
  94 {
  95         int count;
  96         char byte;
  97
  98         if ((addr & 1) == 0) {
  99                 /* is device writable? */
 100                 if (!iicbus_start(dev, addr, 0)) {
 101                         iicbus_stop(dev);
 102                         return (1);
 103                 }
 104         } else {
 105                 /* is device readable? */
 106                 if (!iicbus_block_read(dev, addr, &byte, 1, &count))
 107                         return (1);
 108         }
 109
 110         return (0);
 111 }
 112 #endif
 113
 114 /*
 115  * We add all the devices which we know about.
 116  * The generic attach routine will attach them if they are alive.
 117  */
 118 static int
 119 iicbus_attach(device_t dev)
 120 {
 121 #if SCAN_IICBUS
 122         unsigned char addr;
 123 #endif
 124
 125         iicbus_reset(dev, IIC_FASTEST, 0, NULL);
 126
 127         /* device probing is meaningless since the bus is supposed to be
 128          * hot-plug. Moreover, some I2C chips do not appreciate random
 129          * accesses like stop after start to fast, reads for less than
 130          * x bytes...
 131          */
 132 #if SCAN_IICBUS
 133         kprintf("Probing for devices on iicbus%d:", device_get_unit(dev));
 134
 135         /* probe any devices */
 136         for (addr = 16; addr < 240; addr++) {
 137                 if (iic_probe_device(dev, (u_char)addr)) {
 138                         kprintf(" <%x>", addr);
 139                 }
 140         }
 141         kprintf("\n");
 142 #endif
 143
 144         device_add_child(dev, "ic", -1);
 145         device_add_child(dev, "iic", -1);
 146         device_add_child(dev, "iicsmb", -1);
 147 #if 0
 148         /* attach any known device */
 149         device_add_child(dev, "iic", -1);
 150 #endif
 151         bus_generic_attach(dev);
 152
 153         return (0);
 154 }
 155
 156 static int
 157 iicbus_detach(device_t dev)
 158 {
 159         iicbus_reset(dev, IIC_FASTEST, 0, NULL);
 160         bus_generic_detach(dev);
 161         return (0);
 162 }
 163
 164 static int
 165 iicbus_add_child(device_t dev, int order, const char *name, int unit)
 166 {
 167
 168         device_add_child_ordered(dev, order, name, unit);
 169         bus_generic_attach(dev);
 170         return (0);
 171 }
 172
 173 int
 174 iicbus_generic_intr(device_t dev, int event, char *buf)
 175 {
 176
 177         return (0);
 178 }
 179
 180 int
 181 iicbus_null_callback(device_t dev, int index, caddr_t data)
 182 {
 183
 184         return (0);
 185 }
 186
 187 int
 188 iicbus_null_repeated_start(device_t dev, u_char addr)
 189 {
 190
 191         return (IIC_ENOTSUPP);
 192 }
 193
 194 DRIVER_MODULE(iicbus, iicbb, iicbus_driver, iicbus_devclass, NULL, NULL);
 195 MODULE_VERSION(iicbus, IICBUS_MODVER);