9c77e81b5d
drivers that implemnt the i2c bit banging bus interface not have to recompile iicbb in order to add an attachment for it. This will mean the bktr and other definitions can go back to their respective drivers.
391 lines
8.6 KiB
C
391 lines
8.6 KiB
C
/*-
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* Copyright (c) 1998, 2001 Nicolas Souchu
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* $FreeBSD$
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*
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*/
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/*
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* Generic I2C bit-banging code
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*
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* Example:
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*
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* iicbus
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* / \
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* iicbb pcf
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* | \
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* bti2c lpbb
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*
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* From Linux I2C generic interface
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* (c) 1998 Gerd Knorr <kraxel@cs.tu-berlin.de>
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*
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*/
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#include <sys/param.h>
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#include <sys/kernel.h>
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#include <sys/systm.h>
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#include <sys/module.h>
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#include <sys/bus.h>
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#include <sys/uio.h>
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#include <dev/iicbus/iiconf.h>
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#include <dev/iicbus/iicbus.h>
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#include <dev/smbus/smbconf.h>
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#include "iicbus_if.h"
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#include "iicbb_if.h"
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struct iicbb_softc {
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device_t iicbus;
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};
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static int iicbb_probe(device_t);
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static int iicbb_attach(device_t);
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static int iicbb_detach(device_t);
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static int iicbb_print_child(device_t, device_t);
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static int iicbb_callback(device_t, int, caddr_t);
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static int iicbb_start(device_t, u_char, int);
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static int iicbb_stop(device_t);
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static int iicbb_write(device_t, char *, int, int *, int);
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static int iicbb_read(device_t, char *, int, int *, int, int);
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static int iicbb_reset(device_t, u_char, u_char, u_char *);
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static device_method_t iicbb_methods[] = {
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/* device interface */
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DEVMETHOD(device_probe, iicbb_probe),
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DEVMETHOD(device_attach, iicbb_attach),
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DEVMETHOD(device_detach, iicbb_detach),
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/* bus interface */
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DEVMETHOD(bus_print_child, iicbb_print_child),
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/* iicbus interface */
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DEVMETHOD(iicbus_callback, iicbb_callback),
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DEVMETHOD(iicbus_start, iicbb_start),
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DEVMETHOD(iicbus_repeated_start, iicbb_start),
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DEVMETHOD(iicbus_stop, iicbb_stop),
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DEVMETHOD(iicbus_write, iicbb_write),
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DEVMETHOD(iicbus_read, iicbb_read),
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DEVMETHOD(iicbus_reset, iicbb_reset),
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{ 0, 0 }
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};
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driver_t iicbb_driver = {
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"iicbb",
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iicbb_methods,
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sizeof(struct iicbb_softc),
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};
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devclass_t iicbb_devclass;
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static int iicbb_probe(device_t dev)
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{
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device_set_desc(dev, "I2C bit-banging driver");
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return (0);
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}
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static int iicbb_attach(device_t dev)
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{
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struct iicbb_softc *sc = (struct iicbb_softc *)device_get_softc(dev);
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bzero(sc, sizeof(struct iicbb_softc));
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sc->iicbus = device_add_child(dev, "iicbus", -1);
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if (!sc->iicbus)
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return (ENXIO);
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bus_generic_attach(dev);
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return (0);
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}
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static int iicbb_detach(device_t dev)
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{
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struct iicbb_softc *sc = (struct iicbb_softc *)device_get_softc(dev);
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if (sc->iicbus) {
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bus_generic_detach(dev);
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device_delete_child(dev, sc->iicbus);
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}
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return (0);
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}
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static int
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iicbb_print_child(device_t bus, device_t dev)
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{
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int error;
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int retval = 0;
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u_char oldaddr;
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retval += bus_print_child_header(bus, dev);
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/* retrieve the interface I2C address */
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error = IICBB_RESET(device_get_parent(bus), IIC_FASTEST, 0, &oldaddr);
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if (error == IIC_ENOADDR) {
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retval += printf(" on %s master-only\n",
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device_get_nameunit(bus));
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} else {
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/* restore the address */
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IICBB_RESET(device_get_parent(bus), IIC_FASTEST, oldaddr, NULL);
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retval += printf(" on %s addr 0x%x\n",
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device_get_nameunit(bus), oldaddr & 0xff);
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}
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return (retval);
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}
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#define IIC_DELAY 10
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#define I2C_SETSDA(dev,val) do { \
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IICBB_SETSDA(device_get_parent(dev), val); \
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DELAY(IIC_DELAY); \
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} while (0)
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#define I2C_SETSCL(dev,val) do { \
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iicbb_setscl(dev, val, 100); \
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} while (0)
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#define I2C_SET(dev,ctrl,data) do { \
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I2C_SETSCL(dev, ctrl); \
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I2C_SETSDA(dev, data); \
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} while (0)
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#define I2C_GETSDA(dev) (IICBB_GETSDA(device_get_parent(dev)))
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#define I2C_GETSCL(dev) (IICBB_GETSCL(device_get_parent(dev)))
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static int i2c_debug = 0;
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#define I2C_DEBUG(x) do { \
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if (i2c_debug) (x); \
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} while (0)
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#define I2C_LOG(format,args...) do { \
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printf(format, args); \
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} while (0)
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static void iicbb_setscl(device_t dev, int val, int timeout)
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{
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int k = 0;
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IICBB_SETSCL(device_get_parent(dev), val);
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DELAY(IIC_DELAY);
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while (val && !I2C_GETSCL(dev) && k++ < timeout) {
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IICBB_SETSCL(device_get_parent(dev), val);
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DELAY(IIC_DELAY);
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}
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return;
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}
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static void iicbb_one(device_t dev, int timeout)
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{
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I2C_SET(dev,0,1);
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I2C_SET(dev,1,1);
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I2C_SET(dev,0,1);
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return;
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}
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static void iicbb_zero(device_t dev, int timeout)
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{
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I2C_SET(dev,0,0);
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I2C_SET(dev,1,0);
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I2C_SET(dev,0,0);
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return;
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}
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/*
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* Waiting for ACKNOWLEDGE.
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*
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* When a chip is being addressed or has received data it will issue an
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* ACKNOWLEDGE pulse. Therefore the MASTER must release the DATA line
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* (set it to high level) and then release the CLOCK line.
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* Now it must wait for the SLAVE to pull the DATA line low.
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* Actually on the bus this looks like a START condition so nothing happens
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* because of the fact that the IC's that have not been addressed are doing
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* nothing.
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*
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* When the SLAVE has pulled this line low the MASTER will take the CLOCK
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* line low and then the SLAVE will release the SDA (data) line.
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*/
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static int iicbb_ack(device_t dev, int timeout)
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{
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int noack;
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int k = 0;
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I2C_SET(dev,0,1);
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I2C_SET(dev,1,1);
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do {
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noack = I2C_GETSDA(dev);
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if (!noack)
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break;
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DELAY(10);
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k += 10;
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} while (k < timeout);
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I2C_SET(dev,0,1);
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I2C_DEBUG(printf("%c ",noack?'-':'+'));
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return (noack);
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}
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static void iicbb_sendbyte(device_t dev, u_char data, int timeout)
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{
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int i;
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for (i=7; i>=0; i--) {
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if (data&(1<<i)) {
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iicbb_one(dev, timeout);
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} else {
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iicbb_zero(dev, timeout);
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}
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}
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I2C_DEBUG(printf("w%02x",(int)data));
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return;
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}
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static u_char iicbb_readbyte(device_t dev, int last, int timeout)
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{
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int i;
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unsigned char data=0;
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I2C_SET(dev,0,1);
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for (i=7; i>=0; i--)
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{
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I2C_SET(dev,1,1);
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if (I2C_GETSDA(dev))
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data |= (1<<i);
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I2C_SET(dev,0,1);
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}
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if (last) {
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iicbb_one(dev, timeout);
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} else {
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iicbb_zero(dev, timeout);
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}
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I2C_DEBUG(printf("r%02x%c ",(int)data,last?'-':'+'));
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return data;
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}
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static int iicbb_callback(device_t dev, int index, caddr_t data)
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{
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return (IICBB_CALLBACK(device_get_parent(dev), index, data));
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}
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static int iicbb_reset(device_t dev, u_char speed, u_char addr, u_char *oldaddr)
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{
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return (IICBB_RESET(device_get_parent(dev), speed, addr, oldaddr));
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}
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static int iicbb_start(device_t dev, u_char slave, int timeout)
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{
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int error;
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I2C_DEBUG(printf("<"));
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I2C_SET(dev,1,1);
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I2C_SET(dev,1,0);
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I2C_SET(dev,0,0);
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/* send address */
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iicbb_sendbyte(dev, slave, timeout);
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/* check for ack */
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if (iicbb_ack(dev, timeout)) {
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error = IIC_ENOACK;
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goto error;
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}
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return(0);
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error:
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iicbb_stop(dev);
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return (error);
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}
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static int iicbb_stop(device_t dev)
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{
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I2C_SET(dev,0,0);
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I2C_SET(dev,1,0);
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I2C_SET(dev,1,1);
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I2C_DEBUG(printf(">"));
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return (0);
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}
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static int iicbb_write(device_t dev, char * buf, int len, int *sent,
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int timeout)
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{
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int bytes, error = 0;
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bytes = 0;
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while (len) {
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/* send byte */
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iicbb_sendbyte(dev,(u_char)*buf++, timeout);
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/* check for ack */
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if (iicbb_ack(dev, timeout)) {
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error = IIC_ENOACK;
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goto error;
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}
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bytes ++;
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len --;
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}
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error:
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*sent = bytes;
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return (error);
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}
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static int iicbb_read(device_t dev, char * buf, int len, int *read,
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int last, int delay)
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{
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int bytes;
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bytes = 0;
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while (len) {
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/* XXX should insert delay here */
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*buf++ = (char)iicbb_readbyte(dev, (len == 1) ? last : 0, delay);
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bytes ++;
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len --;
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}
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*read = bytes;
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return (0);
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}
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DRIVER_MODULE(iicbb, bktr, iicbb_driver, iicbb_devclass, 0, 0);
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DRIVER_MODULE(iicbb, lpbb, iicbb_driver, iicbb_devclass, 0, 0);
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DRIVER_MODULE(iicbb, viapm, iicbb_driver, iicbb_devclass, 0, 0);
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MODULE_DEPEND(iicbb, iicbus, IICBUS_MINVER, IICBUS_PREFVER, IICBUS_MAXVER);
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MODULE_VERSION(iicbb, IICBB_MODVER);
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