Annotation of sys/dev/i2c/i2c_exec.c, Revision 1.1.1.1
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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