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/* $OpenBSD: i2c_exec.c,v 1.2 2008/04/17 16:48:40 deraadt Exp $ */
/* $NetBSD: i2c_exec.c,v 1.3 2003/10/29 00:34:58 mycroft Exp $ */
/*
* Copyright (c) 2003 Wasabi Systems, Inc.
* All rights reserved.
*
* Written by Jason R. Thorpe for Wasabi Systems, Inc.
*
* 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 for the NetBSD Project by
* Wasabi Systems, Inc.
* 4. The name of Wasabi Systems, Inc. may not be used to endorse
* or promote products derived from this software without specific prior
* written permission.
*
* THIS SOFTWARE IS PROVIDED BY WASABI SYSTEMS, INC. ``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 WASABI SYSTEMS, INC
* 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/param.h>
#include <sys/systm.h>
#include <sys/device.h>
#include <sys/event.h>
#include <sys/conf.h>
#define _I2C_PRIVATE
#include <dev/i2c/i2cvar.h>
/*
* iic_exec:
*
* Simplified I2C client interface engine.
*
* This and the SMBus routines are the preferred interface for
* client access to I2C/SMBus, since many automated controllers
* do not provide access to the low-level primitives of the I2C
* bus protocol.
*/
int
iic_exec(i2c_tag_t tag, i2c_op_t op, i2c_addr_t addr, const void *vcmd,
size_t cmdlen, void *vbuf, size_t buflen, int flags)
{
const uint8_t *cmd = vcmd;
uint8_t *buf = vbuf;
int error;
size_t len;
/*
* Defer to the controller if it provides an exec function. Use
* it if it does.
*/
if (tag->ic_exec != NULL)
return ((*tag->ic_exec)(tag->ic_cookie, op, addr, cmd,
cmdlen, buf, buflen, flags));
if ((len = cmdlen) != 0) {
if ((error = iic_initiate_xfer(tag, addr, flags)) != 0)
goto bad;
while (len--) {
if ((error = iic_write_byte(tag, *cmd++, flags)) != 0)
goto bad;
}
}
if (I2C_OP_READ_P(op))
flags |= I2C_F_READ;
len = buflen;
while (len--) {
if (len == 0 && I2C_OP_STOP_P(op))
flags |= I2C_F_STOP;
if (I2C_OP_READ_P(op)) {
/* Send REPEATED START. */
if ((len + 1) == buflen &&
(error = iic_initiate_xfer(tag, addr, flags)) != 0)
goto bad;
/* NACK on last byte. */
if (len == 0)
flags |= I2C_F_LAST;
if ((error = iic_read_byte(tag, buf++, flags)) != 0)
goto bad;
} else {
/* Maybe send START. */
if ((len + 1) == buflen && cmdlen == 0 &&
(error = iic_initiate_xfer(tag, addr, flags)) != 0)
goto bad;
if ((error = iic_write_byte(tag, *buf++, flags)) != 0)
goto bad;
}
}
return (0);
bad:
iic_send_stop(tag, flags);
return (error);
}
/*
* iic_smbus_write_byte:
*
* Perform an SMBus "write byte" operation.
*/
int
iic_smbus_write_byte(i2c_tag_t tag, i2c_addr_t addr, uint8_t cmd,
uint8_t val, int flags)
{
return (iic_exec(tag, I2C_OP_WRITE_WITH_STOP, addr,
&cmd, sizeof cmd, &val, sizeof val, flags));
}
/*
* iic_smbus_read_byte:
*
* Perform an SMBus "read byte" operation.
*/
int
iic_smbus_read_byte(i2c_tag_t tag, i2c_addr_t addr, uint8_t cmd,
uint8_t *valp, int flags)
{
return (iic_exec(tag, I2C_OP_READ_WITH_STOP, addr,
&cmd, sizeof cmd, valp, sizeof (*valp), flags));
}
/*
* iic_smbus_receive_byte:
*
* Perform an SMBus "receive byte" operation.
*/
int
iic_smbus_receive_byte(i2c_tag_t tag, i2c_addr_t addr, uint8_t *valp,
int flags)
{
return (iic_exec(tag, I2C_OP_READ_WITH_STOP, addr,
NULL, 0, valp, sizeof (*valp), flags));
}
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