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 }