103 lines
3.7 KiB
C
103 lines
3.7 KiB
C
/* $NetBSD: i2c_bus.c,v 1.1 1997/10/17 17:21:14 bouyer Exp $ */
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/*
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* Copyright (c) 1997 Manuel Bouyer. 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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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by Manuel Bouyer.
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* 4. The name of the author may not be used to endorse or promote products
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* derived from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/kernel.h>
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#include <dev/i2c/i2c_bus.h>
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/* Support functions for the i2c serial bus */
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void i2c_send_start(adapter)
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i2c_adapter_t * adapter;
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{
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adapter->set_bit(adapter->adapter_softc, I2C_CLOCK);
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adapter->set_bit(adapter->adapter_softc, I2C_DATA);
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adapter->set_bit(adapter->adapter_softc, I2C_TXEN);
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adapter->clr_bit(adapter->adapter_softc, I2C_DATA);
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adapter->clr_bit(adapter->adapter_softc, I2C_CLOCK);
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}
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void i2c_send_stop(adapter)
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i2c_adapter_t * adapter;
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{
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adapter->set_bit(adapter->adapter_softc, I2C_DATA);
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adapter->set_bit(adapter->adapter_softc, I2C_CLOCK);
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adapter->clr_bit(adapter->adapter_softc, I2C_CLOCK);
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adapter->clr_bit(adapter->adapter_softc, I2C_DATA);
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adapter->set_bit(adapter->adapter_softc, I2C_CLOCK);
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adapter->set_bit(adapter->adapter_softc, I2C_DATA);
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}
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int i2c_write_byte(adapter, byte)
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i2c_adapter_t *adapter;
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u_int8_t byte;
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{
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u_int8_t mask;
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int retval;
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adapter->set_bit(adapter->adapter_softc, I2C_TXEN);
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for (mask = 0x80; mask != 0; mask = mask >> 1) {
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if (byte & mask)
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adapter->set_bit(adapter->adapter_softc, I2C_DATA);
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else
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adapter->clr_bit(adapter->adapter_softc, I2C_DATA);
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adapter->set_bit(adapter->adapter_softc, I2C_CLOCK);
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adapter->clr_bit(adapter->adapter_softc, I2C_CLOCK);
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}
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adapter->clr_bit(adapter->adapter_softc, I2C_TXEN);
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adapter->set_bit(adapter->adapter_softc, I2C_CLOCK);
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retval = adapter->read_bit(adapter->adapter_softc, I2C_DATA);
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adapter->clr_bit(adapter->adapter_softc, I2C_CLOCK);
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/* XXX adapter->set_bit(adapter->adapter_softc, I2C_TXEN); */
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return retval;
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}
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int i2c_read_byte(adapter)
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i2c_adapter_t *adapter;
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{
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int i;
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u_int8_t retval = 0;
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adapter->clr_bit(adapter->adapter_softc, I2C_TXEN);
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for (i=0; i < 8; i++) {
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retval = retval << 1;
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adapter->set_bit(adapter->adapter_softc, I2C_CLOCK);
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if (adapter->read_bit(adapter->adapter_softc, I2C_DATA))
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retval |= 1;
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adapter->clr_bit(adapter->adapter_softc, I2C_CLOCK);
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}
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return retval;
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}
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