1 /* $OpenBSD: i2c_exec.c,v 1.3 2015/03/14 03:38:47 jsg 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
44 #define _I2C_PRIVATE
45 #include <dev/i2c/i2cvar.h>
46
47 /*
48 * iic_exec:
49 *
50 * Simplified I2C client interface engine.
51 *
52 * This and the SMBus routines are the preferred interface for
53 * client access to I2C/SMBus, since many automated controllers
54 * do not provide access to the low-level primitives of the I2C
55 * bus protocol.
56 */
57 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)58 iic_exec(i2c_tag_t tag, i2c_op_t op, i2c_addr_t addr, const void *vcmd,
59 size_t cmdlen, void *vbuf, size_t buflen, int flags)
60 {
61 const uint8_t *cmd = vcmd;
62 uint8_t *buf = vbuf;
63 int error;
64 size_t len;
65
66 /*
67 * Defer to the controller if it provides an exec function. Use
68 * it if it does.
69 */
70 if (tag->ic_exec != NULL)
71 return ((*tag->ic_exec)(tag->ic_cookie, op, addr, cmd,
72 cmdlen, buf, buflen, flags));
73
74 if ((len = cmdlen) != 0) {
75 if ((error = iic_initiate_xfer(tag, addr, flags)) != 0)
76 goto bad;
77 while (len--) {
78 if ((error = iic_write_byte(tag, *cmd++, flags)) != 0)
79 goto bad;
80 }
81 }
82
83 if (I2C_OP_READ_P(op))
84 flags |= I2C_F_READ;
85
86 len = buflen;
87 while (len--) {
88 if (len == 0 && I2C_OP_STOP_P(op))
89 flags |= I2C_F_STOP;
90 if (I2C_OP_READ_P(op)) {
91 /* Send REPEATED START. */
92 if ((len + 1) == buflen &&
93 (error = iic_initiate_xfer(tag, addr, flags)) != 0)
94 goto bad;
95 /* NACK on last byte. */
96 if (len == 0)
97 flags |= I2C_F_LAST;
98 if ((error = iic_read_byte(tag, buf++, flags)) != 0)
99 goto bad;
100 } else {
101 /* Maybe send START. */
102 if ((len + 1) == buflen && cmdlen == 0 &&
103 (error = iic_initiate_xfer(tag, addr, flags)) != 0)
104 goto bad;
105 if ((error = iic_write_byte(tag, *buf++, flags)) != 0)
106 goto bad;
107 }
108 }
109
110 return (0);
111 bad:
112 iic_send_stop(tag, flags);
113 return (error);
114 }
115
116 /*
117 * iic_smbus_write_byte:
118 *
119 * Perform an SMBus "write byte" operation.
120 */
121 int
iic_smbus_write_byte(i2c_tag_t tag,i2c_addr_t addr,uint8_t cmd,uint8_t val,int flags)122 iic_smbus_write_byte(i2c_tag_t tag, i2c_addr_t addr, uint8_t cmd,
123 uint8_t val, int flags)
124 {
125
126 return (iic_exec(tag, I2C_OP_WRITE_WITH_STOP, addr,
127 &cmd, sizeof cmd, &val, sizeof val, flags));
128 }
129
130 /*
131 * iic_smbus_read_byte:
132 *
133 * Perform an SMBus "read byte" operation.
134 */
135 int
iic_smbus_read_byte(i2c_tag_t tag,i2c_addr_t addr,uint8_t cmd,uint8_t * valp,int flags)136 iic_smbus_read_byte(i2c_tag_t tag, i2c_addr_t addr, uint8_t cmd,
137 uint8_t *valp, int flags)
138 {
139
140 return (iic_exec(tag, I2C_OP_READ_WITH_STOP, addr,
141 &cmd, sizeof cmd, valp, sizeof (*valp), flags));
142 }
143
144 /*
145 * iic_smbus_receive_byte:
146 *
147 * Perform an SMBus "receive byte" operation.
148 */
149 int
iic_smbus_receive_byte(i2c_tag_t tag,i2c_addr_t addr,uint8_t * valp,int flags)150 iic_smbus_receive_byte(i2c_tag_t tag, i2c_addr_t addr, uint8_t *valp,
151 int flags)
152 {
153
154 return (iic_exec(tag, I2C_OP_READ_WITH_STOP, addr,
155 NULL, 0, valp, sizeof (*valp), flags));
156 }
157