157 lines
4.4 KiB
C
157 lines
4.4 KiB
C
/* $NetBSD: i2c_exec.c,v 1.4 2005/12/11 12:21:22 christos Exp $ */
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/*
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* Copyright (c) 2003 Wasabi Systems, Inc.
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* All rights reserved.
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*
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* Written by Jason R. Thorpe for Wasabi Systems, Inc.
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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 for the NetBSD Project by
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* Wasabi Systems, Inc.
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* 4. The name of Wasabi Systems, Inc. may not be used to endorse
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* or promote products derived from this software without specific prior
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* written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY WASABI SYSTEMS, INC. ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
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* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL WASABI SYSTEMS, INC
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* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* 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/device.h>
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#include <sys/event.h>
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#include <sys/conf.h>
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#define _I2C_PRIVATE
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#include <dev/i2c/i2cvar.h>
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/*
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* iic_exec:
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*
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* Simplified I2C client interface engine.
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*
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* This and the SMBus routines are the preferred interface for
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* client access to I2C/SMBus, since many automated controllers
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* do not provide access to the low-level primitives of the I2C
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* bus protocol.
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*/
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int
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iic_exec(i2c_tag_t tag, i2c_op_t op, i2c_addr_t addr, const void *vcmd,
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size_t cmdlen, void *vbuf, size_t buflen, int flags)
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{
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const uint8_t *cmd = vcmd;
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uint8_t *buf = vbuf;
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int error;
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size_t len;
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/*
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* Defer to the controller if it provides an exec function. Use
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* it if it does.
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*/
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if (tag->ic_exec != NULL)
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return ((*tag->ic_exec)(tag->ic_cookie, op, addr, cmd,
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cmdlen, buf, buflen, flags));
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if ((len = cmdlen) != 0) {
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if ((error = iic_initiate_xfer(tag, addr, flags)) != 0)
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goto bad;
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while (len--) {
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if ((error = iic_write_byte(tag, *cmd++, flags)) != 0)
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goto bad;
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}
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}
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if (I2C_OP_READ_P(op))
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flags |= I2C_F_READ;
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len = buflen;
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while (len--) {
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if (len == 0 && I2C_OP_STOP_P(op))
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flags |= I2C_F_STOP;
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if (I2C_OP_READ_P(op)) {
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/* Send REPEATED START. */
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if ((len + 1) == buflen &&
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(error = iic_initiate_xfer(tag, addr, flags)) != 0)
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goto bad;
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/* NACK on last byte. */
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if (len == 0)
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flags |= I2C_F_LAST;
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if ((error = iic_read_byte(tag, buf++, flags)) != 0)
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goto bad;
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} else {
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/* Maybe send START. */
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if ((len + 1) == buflen && cmdlen == 0 &&
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(error = iic_initiate_xfer(tag, addr, flags)) != 0)
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goto bad;
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if ((error = iic_write_byte(tag, *buf++, flags)) != 0)
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goto bad;
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}
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}
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return (0);
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bad:
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iic_send_stop(tag, flags);
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return (error);
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}
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/*
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* iic_smbus_write_byte:
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*
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* Perform an SMBus "write byte" operation.
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*/
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int
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iic_smbus_write_byte(i2c_tag_t tag, i2c_addr_t addr, uint8_t cmd,
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uint8_t val, int flags)
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{
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return (iic_exec(tag, I2C_OP_WRITE_WITH_STOP, addr, &cmd, 1,
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&val, 1, flags));
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}
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/*
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* iic_smbus_read_byte:
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*
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* Perform an SMBus "read byte" operation.
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*/
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int
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iic_smbus_read_byte(i2c_tag_t tag, i2c_addr_t addr, uint8_t cmd,
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uint8_t *valp, int flags)
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{
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return (iic_exec(tag, I2C_OP_READ_WITH_STOP, addr, &cmd, 1,
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valp, 1, flags));
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}
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/*
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* iic_smbus_receive_byte:
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*
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* Perform an SMBus "receive byte" operation.
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*/
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int
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iic_smbus_receive_byte(i2c_tag_t tag, i2c_addr_t addr, uint8_t *valp,
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int flags)
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{
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return (iic_exec(tag, I2C_OP_READ_WITH_STOP, addr, NULL, 0,
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valp, 1, flags));
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}
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