1 /* $OpenBSD: i2c_exec.c,v 1.2 2008/04/17 16:48:40 deraadt 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, 128 &cmd, sizeof cmd, &val, sizeof val, 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, 142 &cmd, sizeof cmd, valp, sizeof (*valp), 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, 156 NULL, 0, valp, sizeof (*valp), flags)); 157 } 158