Annotation of sys/dev/i2c/i2c_exec.c, Revision 1.1
1.1 ! nbrk 1: /* $OpenBSD: i2c_exec.c,v 1.1 2004/05/23 17:33:43 grange Exp $ */
! 2: /* $NetBSD: i2c_exec.c,v 1.3 2003/10/29 00:34:58 mycroft Exp $ */
! 3:
! 4: /*
! 5: * Copyright (c) 2003 Wasabi Systems, Inc.
! 6: * All rights reserved.
! 7: *
! 8: * Written by Jason R. Thorpe for Wasabi Systems, Inc.
! 9: *
! 10: * Redistribution and use in source and binary forms, with or without
! 11: * modification, are permitted provided that the following conditions
! 12: * are met:
! 13: * 1. Redistributions of source code must retain the above copyright
! 14: * notice, this list of conditions and the following disclaimer.
! 15: * 2. Redistributions in binary form must reproduce the above copyright
! 16: * notice, this list of conditions and the following disclaimer in the
! 17: * documentation and/or other materials provided with the distribution.
! 18: * 3. All advertising materials mentioning features or use of this software
! 19: * must display the following acknowledgement:
! 20: * This product includes software developed for the NetBSD Project by
! 21: * Wasabi Systems, Inc.
! 22: * 4. The name of Wasabi Systems, Inc. may not be used to endorse
! 23: * or promote products derived from this software without specific prior
! 24: * written permission.
! 25: *
! 26: * THIS SOFTWARE IS PROVIDED BY WASABI SYSTEMS, INC. ``AS IS'' AND
! 27: * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
! 28: * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
! 29: * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL WASABI SYSTEMS, INC
! 30: * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
! 31: * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
! 32: * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
! 33: * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
! 34: * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
! 35: * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
! 36: * POSSIBILITY OF SUCH DAMAGE.
! 37: */
! 38:
! 39: #include <sys/param.h>
! 40: #include <sys/systm.h>
! 41: #include <sys/device.h>
! 42: #include <sys/event.h>
! 43: #include <sys/conf.h>
! 44:
! 45: #define _I2C_PRIVATE
! 46: #include <dev/i2c/i2cvar.h>
! 47:
! 48: /*
! 49: * iic_exec:
! 50: *
! 51: * Simplified I2C client interface engine.
! 52: *
! 53: * This and the SMBus routines are the preferred interface for
! 54: * client access to I2C/SMBus, since many automated controllers
! 55: * do not provide access to the low-level primitives of the I2C
! 56: * bus protocol.
! 57: */
! 58: int
! 59: iic_exec(i2c_tag_t tag, i2c_op_t op, i2c_addr_t addr, const void *vcmd,
! 60: size_t cmdlen, void *vbuf, size_t buflen, int flags)
! 61: {
! 62: const uint8_t *cmd = vcmd;
! 63: uint8_t *buf = vbuf;
! 64: int error;
! 65: size_t len;
! 66:
! 67: /*
! 68: * Defer to the controller if it provides an exec function. Use
! 69: * it if it does.
! 70: */
! 71: if (tag->ic_exec != NULL)
! 72: return ((*tag->ic_exec)(tag->ic_cookie, op, addr, cmd,
! 73: cmdlen, buf, buflen, flags));
! 74:
! 75: if ((len = cmdlen) != 0) {
! 76: if ((error = iic_initiate_xfer(tag, addr, flags)) != 0)
! 77: goto bad;
! 78: while (len--) {
! 79: if ((error = iic_write_byte(tag, *cmd++, flags)) != 0)
! 80: goto bad;
! 81: }
! 82: }
! 83:
! 84: if (I2C_OP_READ_P(op))
! 85: flags |= I2C_F_READ;
! 86:
! 87: len = buflen;
! 88: while (len--) {
! 89: if (len == 0 && I2C_OP_STOP_P(op))
! 90: flags |= I2C_F_STOP;
! 91: if (I2C_OP_READ_P(op)) {
! 92: /* Send REPEATED START. */
! 93: if ((len + 1) == buflen &&
! 94: (error = iic_initiate_xfer(tag, addr, flags)) != 0)
! 95: goto bad;
! 96: /* NACK on last byte. */
! 97: if (len == 0)
! 98: flags |= I2C_F_LAST;
! 99: if ((error = iic_read_byte(tag, buf++, flags)) != 0)
! 100: goto bad;
! 101: } else {
! 102: /* Maybe send START. */
! 103: if ((len + 1) == buflen && cmdlen == 0 &&
! 104: (error = iic_initiate_xfer(tag, addr, flags)) != 0)
! 105: goto bad;
! 106: if ((error = iic_write_byte(tag, *buf++, flags)) != 0)
! 107: goto bad;
! 108: }
! 109: }
! 110:
! 111: return (0);
! 112: bad:
! 113: iic_send_stop(tag, flags);
! 114: return (error);
! 115: }
! 116:
! 117: /*
! 118: * iic_smbus_write_byte:
! 119: *
! 120: * Perform an SMBus "write byte" operation.
! 121: */
! 122: int
! 123: iic_smbus_write_byte(i2c_tag_t tag, i2c_addr_t addr, uint8_t cmd,
! 124: uint8_t val, int flags)
! 125: {
! 126:
! 127: return (iic_exec(tag, I2C_OP_WRITE_WITH_STOP, addr, &cmd, 1,
! 128: &val, 1, flags));
! 129: }
! 130:
! 131: /*
! 132: * iic_smbus_read_byte:
! 133: *
! 134: * Perform an SMBus "read byte" operation.
! 135: */
! 136: int
! 137: iic_smbus_read_byte(i2c_tag_t tag, i2c_addr_t addr, uint8_t cmd,
! 138: uint8_t *valp, int flags)
! 139: {
! 140:
! 141: return (iic_exec(tag, I2C_OP_READ_WITH_STOP, addr, &cmd, 1,
! 142: valp, 1, flags));
! 143: }
! 144:
! 145: /*
! 146: * iic_smbus_receive_byte:
! 147: *
! 148: * Perform an SMBus "receive byte" operation.
! 149: */
! 150: int
! 151: iic_smbus_receive_byte(i2c_tag_t tag, i2c_addr_t addr, uint8_t *valp,
! 152: int flags)
! 153: {
! 154:
! 155: return (iic_exec(tag, I2C_OP_READ_WITH_STOP, addr, NULL, 0,
! 156: valp, 1, flags));
! 157: }
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