NetBSD/sys/dev/i2c/i2c_bus.c

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2001-11-13 15:24:11 +03:00
/* $NetBSD: i2c_bus.c,v 1.2 2001/11/13 12:25:27 lukem Exp $ */
/*
* Copyright (c) 1997 Manuel Bouyer. 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.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by Manuel Bouyer.
* 4. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 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.
*/
2001-11-13 15:24:11 +03:00
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: i2c_bus.c,v 1.2 2001/11/13 12:25:27 lukem Exp $");
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <dev/i2c/i2c_bus.h>
/* Support functions for the i2c serial bus */
void i2c_send_start(adapter)
i2c_adapter_t * adapter;
{
adapter->set_bit(adapter->adapter_softc, I2C_CLOCK);
adapter->set_bit(adapter->adapter_softc, I2C_DATA);
adapter->set_bit(adapter->adapter_softc, I2C_TXEN);
adapter->clr_bit(adapter->adapter_softc, I2C_DATA);
adapter->clr_bit(adapter->adapter_softc, I2C_CLOCK);
}
void i2c_send_stop(adapter)
i2c_adapter_t * adapter;
{
adapter->set_bit(adapter->adapter_softc, I2C_DATA);
adapter->set_bit(adapter->adapter_softc, I2C_CLOCK);
adapter->clr_bit(adapter->adapter_softc, I2C_CLOCK);
adapter->clr_bit(adapter->adapter_softc, I2C_DATA);
adapter->set_bit(adapter->adapter_softc, I2C_CLOCK);
adapter->set_bit(adapter->adapter_softc, I2C_DATA);
}
int i2c_write_byte(adapter, byte)
i2c_adapter_t *adapter;
u_int8_t byte;
{
u_int8_t mask;
int retval;
adapter->set_bit(adapter->adapter_softc, I2C_TXEN);
for (mask = 0x80; mask != 0; mask = mask >> 1) {
if (byte & mask)
adapter->set_bit(adapter->adapter_softc, I2C_DATA);
else
adapter->clr_bit(adapter->adapter_softc, I2C_DATA);
adapter->set_bit(adapter->adapter_softc, I2C_CLOCK);
adapter->clr_bit(adapter->adapter_softc, I2C_CLOCK);
}
adapter->clr_bit(adapter->adapter_softc, I2C_TXEN);
adapter->set_bit(adapter->adapter_softc, I2C_CLOCK);
retval = adapter->read_bit(adapter->adapter_softc, I2C_DATA);
adapter->clr_bit(adapter->adapter_softc, I2C_CLOCK);
/* XXX adapter->set_bit(adapter->adapter_softc, I2C_TXEN); */
return retval;
}
int i2c_read_byte(adapter)
i2c_adapter_t *adapter;
{
int i;
u_int8_t retval = 0;
adapter->clr_bit(adapter->adapter_softc, I2C_TXEN);
for (i=0; i < 8; i++) {
retval = retval << 1;
adapter->set_bit(adapter->adapter_softc, I2C_CLOCK);
if (adapter->read_bit(adapter->adapter_softc, I2C_DATA))
retval |= 1;
adapter->clr_bit(adapter->adapter_softc, I2C_CLOCK);
}
return retval;
}