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232 lines
5.1 KiB
C
232 lines
5.1 KiB
C
/*-
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* Copyright (c) 1998 Nicolas Souchu, Marc Bouget
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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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* I2C Bit-Banging over parallel port
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*
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* See the Official Philips interface description in lpbb(4)
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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/ppbus/ppbconf.h>
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#include "ppbus_if.h"
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#include <dev/ppbus/ppbio.h>
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#include <dev/iicbus/iiconf.h>
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#include <dev/iicbus/iicbus.h>
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#include "iicbb_if.h"
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static int lpbb_detect(device_t dev);
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static void
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lpbb_identify(driver_t *driver, device_t parent)
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{
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BUS_ADD_CHILD(parent, 0, "lpbb", 0);
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}
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static int
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lpbb_probe(device_t dev)
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{
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/* Perhaps call this during identify instead? */
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if (!lpbb_detect(dev))
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return (ENXIO);
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device_set_desc(dev, "Parallel I2C bit-banging interface");
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return (0);
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}
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static int
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lpbb_attach(device_t dev)
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{
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device_t bitbang, iicbus;
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/* add generic bit-banging code */
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bitbang = device_add_child(dev, "iicbb", -1);
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/* add the iicbus to the tree */
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iicbus = iicbus_alloc_bus(bitbang);
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device_probe_and_attach(bitbang);
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/* XXX should be in iicbb_attach! */
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device_probe_and_attach(iicbus);
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return (0);
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}
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static int
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lpbb_callback(device_t dev, int index, caddr_t *data)
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{
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device_t ppbus = device_get_parent(dev);
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int error = 0;
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int how;
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switch (index) {
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case IIC_REQUEST_BUS:
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/* request the ppbus */
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how = *(int *)data;
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error = ppb_request_bus(ppbus, dev, how);
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break;
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case IIC_RELEASE_BUS:
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/* release the ppbus */
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error = ppb_release_bus(ppbus, dev);
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break;
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default:
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error = EINVAL;
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}
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return (error);
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}
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#define SDA_out 0x80
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#define SCL_out 0x08
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#define SDA_in 0x80
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#define SCL_in 0x08
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#define ALIM 0x20
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#define I2CKEY 0x50
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static int getSDA(device_t ppbus)
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{
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if((ppb_rstr(ppbus)&SDA_in)==SDA_in)
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return 1;
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else
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return 0;
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}
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static void setSDA(device_t ppbus, char val)
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{
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if(val==0)
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ppb_wdtr(ppbus, (u_char)SDA_out);
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else
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ppb_wdtr(ppbus, (u_char)~SDA_out);
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}
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static void setSCL(device_t ppbus, unsigned char val)
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{
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if(val==0)
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ppb_wctr(ppbus, (u_char)(ppb_rctr(ppbus)&~SCL_out));
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else
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ppb_wctr(ppbus, (u_char)(ppb_rctr(ppbus)|SCL_out));
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}
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static int lpbb_detect(device_t dev)
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{
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device_t ppbus = device_get_parent(dev);
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if (ppb_request_bus(ppbus, dev, PPB_DONTWAIT)) {
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device_printf(dev, "can't allocate ppbus\n");
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return (0);
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}
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/* reset bus */
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setSDA(ppbus, 1);
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setSCL(ppbus, 1);
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if ((ppb_rstr(ppbus) & I2CKEY) ||
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((ppb_rstr(ppbus) & ALIM) != ALIM)) {
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ppb_release_bus(ppbus, dev);
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return (0);
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}
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ppb_release_bus(ppbus, dev);
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return (1);
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}
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static int
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lpbb_reset(device_t dev, u_char speed, u_char addr, u_char * oldaddr)
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{
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device_t ppbus = device_get_parent(dev);
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/* reset bus */
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setSDA(ppbus, 1);
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setSCL(ppbus, 1);
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return (IIC_ENOADDR);
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}
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static void
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lpbb_setlines(device_t dev, int ctrl, int data)
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{
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device_t ppbus = device_get_parent(dev);
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setSCL(ppbus, ctrl);
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setSDA(ppbus, data);
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}
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static int
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lpbb_getdataline(device_t dev)
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{
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device_t ppbus = device_get_parent(dev);
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return (getSDA(ppbus));
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}
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static devclass_t lpbb_devclass;
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static device_method_t lpbb_methods[] = {
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/* device interface */
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DEVMETHOD(device_identify, lpbb_identify),
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DEVMETHOD(device_probe, lpbb_probe),
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DEVMETHOD(device_attach, lpbb_attach),
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/* bus interface */
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DEVMETHOD(bus_print_child, bus_generic_print_child),
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/* iicbb interface */
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DEVMETHOD(iicbb_callback, lpbb_callback),
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DEVMETHOD(iicbb_setlines, lpbb_setlines),
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DEVMETHOD(iicbb_getdataline, lpbb_getdataline),
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DEVMETHOD(iicbb_reset, lpbb_reset),
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{ 0, 0 }
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};
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static driver_t lpbb_driver = {
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"lpbb",
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lpbb_methods,
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1,
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};
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DRIVER_MODULE(lpbb, ppbus, lpbb_driver, lpbb_devclass, 0, 0);
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