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freebsd/sys/dev/iicbus/iicbus.c
Warner Losh d7fac9732b Allow iic bridges to support a generalized transfer, rather than
forcing all transfers to do the start read/write stop by hand.  Some
smart bridges prefer this sort of operation, and this allows us to
support their features more easily.  When bridges don't support it, we
fall back to using the old-style opertaions.  Expand the ioctl
interface to expose this function.  Unlike the old-style interface,
this interface is thread safe, even on old bridges.
2006-07-14 23:15:06 +00:00

194 lines
4.7 KiB
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/module.h>
#include <sys/bus.h>
#include <dev/iicbus/iiconf.h>
#include <dev/iicbus/iicbus.h>
#include "iicbus_if.h"
#define DEVTOIICBUS(dev) ((struct iicbus_device*)device_get_ivars(dev))
devclass_t iicbus_devclass;
/* See comments below for why auto-scanning is a bad idea. */
#define SCAN_IICBUS 0
/*
* Device methods
*/
static int iicbus_probe(device_t);
static int iicbus_attach(device_t);
static int iicbus_detach(device_t);
static int iicbus_add_child(device_t dev, int order, const char *name, int unit);
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_driver_added, bus_generic_driver_added),
DEVMETHOD(bus_print_child, bus_generic_print_child),
{ 0, 0 }
};
driver_t iicbus_driver = {
"iicbus",
iicbus_methods,
sizeof(struct iicbus_softc),
};
static int
iicbus_probe(device_t dev)
{
device_set_desc(dev, "Philips I2C bus");
return (0);
}
#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
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
device_add_child(dev, "ic", -1);
device_add_child(dev, "iicsmb", -1);
#if 0
/* attach any known device */
device_add_child(dev, "iic", -1);
#endif
bus_generic_attach(dev);
return (0);
}
static int
iicbus_detach(device_t dev)
{
iicbus_reset(dev, IIC_FASTEST, 0, NULL);
bus_generic_detach(dev);
return (0);
}
static int
iicbus_add_child(device_t dev, int order, const char *name, int unit)
{
device_add_child_ordered(dev, order, name, unit);
bus_generic_attach(dev);
return (0);
}
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);
}
DRIVER_MODULE(iicbus, envctrl, iicbus_driver, iicbus_devclass, 0, 0);
DRIVER_MODULE(iicbus, iicbb, iicbus_driver, iicbus_devclass, 0, 0);
MODULE_VERSION(iicbus, IICBUS_MODVER);