I2C framework originally written by Steve C. Woodford and Jason R. Thorpe

for NetBSD (r).

This framework supports various i2c master controllers:
- dumb bit-bang controllers
- a few styles of automated controllers that give you control
over sending start/stop conditions on the i2c bus
- automated controllers that are too smart for its own good,
giving software no control over start/stop conditions
- smbus controllers by emulating smbus protocol with i2c commands

i2c slave devices need their addresses to be specified in the kernel
config file, no device discovery presented.

ok deraadt@

8 files changed, 793 insertions, 1 deletions

diff --git a/sys/conf/files b/sys/conf/files
index e4f4645cf41..7ddc5cf233a 100644
--- a/sys/conf/files
+++ b/sys/conf/files
@@ -1,4 +1,4 @@
-#	$OpenBSD: files,v 1.297 2004/05/20 03:04:37 marco Exp $
+#	$OpenBSD: files,v 1.298 2004/05/23 17:33:43 grange Exp $
 #	$NetBSD: files,v 1.87 1996/05/19 17:17:50 jonathan Exp $
 
 #	@(#)files.newconf	7.5 (Berkeley) 5/10/93
@@ -16,6 +16,7 @@ define	mii {[phy = -1]}
 define	midibus { }
 define	midisyn
 define	radiobus {}
+define	i2cbus {}
 
 # audio device attributes
 define	mulaw
@@ -74,6 +75,10 @@ define	wskbddev {[console = -1], [mux = -1]}
 define	wsmousedev {[mux = -1]}
 define	wsrasteremulops
 
+# i2c device attributes
+define	i2cexec
+define	i2c_bitbang
+
 # SMC 93Cx6 Serial EEPROM devices
 define	smc93cx6
 file	dev/ic/smc93cx6.c		smc93cx6
diff --git a/sys/dev/i2c/files.i2c b/sys/dev/i2c/files.i2c
new file mode 100644
index 00000000000..c53863d6ec2
--- /dev/null
+++ b/sys/dev/i2c/files.i2c
@@ -0,0 +1,10 @@
+# $OpenBSD: files.i2c,v 1.1 2004/05/23 17:33:43 grange Exp $
+#	$NetBSD: files.i2c,v 1.3 2003/10/20 16:24:10 briggs Exp $
+
+device	iic { addr, [size = -1] }
+attach	iic at i2cbus
+file	dev/i2c/i2c.c				iic | i2cbus
+file	dev/i2c/i2c_exec.c			iic | i2cbus | i2cexec
+
+# Common module for bit-bang'ing an I2C bus
+file	dev/i2c/i2c_bitbang.c			i2c_bitbang
diff --git a/sys/dev/i2c/i2c.c b/sys/dev/i2c/i2c.c
new file mode 100644
index 00000000000..8cfd6c8cbba
--- /dev/null
+++ b/sys/dev/i2c/i2c.c
@@ -0,0 +1,133 @@
+/*	$OpenBSD: i2c.c,v 1.1 2004/05/23 17:33:43 grange Exp $	*/
+/*	$NetBSD: i2c.c,v 1.1 2003/09/30 00:35:31 thorpej Exp $	*/
+
+/*
+ * Copyright (c) 2003 Wasabi Systems, Inc.
+ * All rights reserved.
+ *
+ * Written by Jason R. Thorpe for Wasabi Systems, Inc.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *      This product includes software developed for the NetBSD Project by
+ *      Wasabi Systems, Inc.
+ * 4. The name of Wasabi Systems, Inc. may not be used to endorse
+ *    or promote products derived from this software without specific prior
+ *    written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY WASABI SYSTEMS, INC. ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
+ * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL WASABI SYSTEMS, INC
+ * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <sys/param.h>
+#include <sys/systm.h>
+#include <sys/device.h>
+#include <sys/event.h>
+#include <sys/conf.h>
+
+#include <dev/i2c/i2cvar.h>
+
+#define IICCF_ADDR	0
+#define IICCF_SIZE	1
+
+struct iic_softc {
+	struct device sc_dev;
+	i2c_tag_t sc_tag;
+};
+
+int	iic_match(struct device *, void *, void *);
+void	iic_attach(struct device *, struct device *, void *);
+int	iic_search(struct device *, void *, void *);
+int	iic_print(void *, const char *);
+
+struct cfattach iic_ca = {
+	sizeof (struct iic_softc),
+	iic_match,
+	iic_attach
+};
+
+struct cfdriver iic_cd = {
+	NULL, "iic", DV_DULL
+};
+
+int
+iicbus_print(void *aux, const char *pnp)
+{
+	struct i2cbus_attach_args *iba = aux;
+
+	if (pnp != NULL)
+		printf("%s at %s", iba->iba_name, pnp);
+
+	return (UNCONF);
+}
+
+int
+iic_print(void *aux, const char *pnp)
+{
+	struct i2c_attach_args *ia = aux;
+
+	printf(" addr 0x%x", ia->ia_addr);
+
+	return (UNCONF);
+}
+
+int
+iic_search(struct device *parent, void *arg, void *aux)
+{
+	struct iic_softc *sc = (void *) parent;
+	struct cfdata *cf = arg;
+	struct i2c_attach_args ia;
+
+	ia.ia_tag = sc->sc_tag;
+	ia.ia_addr = cf->cf_loc[IICCF_ADDR];
+	ia.ia_size = cf->cf_loc[IICCF_SIZE];
+
+	if (cf->cf_attach->ca_match(parent, cf, &ia) > 0)
+		config_attach(parent, cf, &ia, iic_print);
+
+	return (0);
+}
+
+int
+iic_match(struct device *parent, void *arg, void *aux)
+{
+	struct cfdata *cf = arg;
+	struct i2cbus_attach_args *iba = aux;
+
+	/* Just make sure we're looking for i2c. */
+	return (strcmp(iba->iba_name, cf->cf_driver->cd_name) == 0);
+}
+
+void
+iic_attach(struct device *parent, struct device *self, void *aux)
+{
+	struct iic_softc *sc = (void *) self;
+	struct i2cbus_attach_args *iba = aux;
+
+	sc->sc_tag = iba->iba_tag;
+
+	printf("\n");
+
+	/*
+	 * Attach all i2c devices described in the kernel
+	 * configuration file.
+	 */
+	config_search(iic_search, self, NULL);
+}
diff --git a/sys/dev/i2c/i2c_bitbang.c b/sys/dev/i2c/i2c_bitbang.c
new file mode 100644
index 00000000000..ba03967c0e8
--- /dev/null
+++ b/sys/dev/i2c/i2c_bitbang.c
@@ -0,0 +1,179 @@
+/*	$OpenBSD: i2c_bitbang.c,v 1.1 2004/05/23 17:33:43 grange Exp $	*/
+/*	$NetBSD: i2c_bitbang.c,v 1.1 2003/09/30 00:35:31 thorpej Exp $	*/
+
+/*
+ * Copyright (c) 2003 Wasabi Systems, Inc.
+ * All rights reserved.
+ *
+ * Written by Jason R. Thorpe for Wasabi Systems, Inc.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *      This product includes software developed for the NetBSD Project by
+ *      Wasabi Systems, Inc.
+ * 4. The name of Wasabi Systems, Inc. may not be used to endorse
+ *    or promote products derived from this software without specific prior
+ *    written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY WASABI SYSTEMS, INC. ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
+ * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL WASABI SYSTEMS, INC
+ * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+/*
+ * Common module for bit-bang'ing an I2C bus.
+ */
+
+#include <sys/param.h>
+
+#include <dev/i2c/i2cvar.h>
+#include <dev/i2c/i2c_bitbang.h>
+
+#define	BB_SET(x)	ops->ibo_set_bits(v, (x))
+#define	BB_DIR(x)	ops->ibo_set_dir(v, (x))
+#define	BB_READ		ops->ibo_read_bits(v)
+
+#define	SDA		ops->ibo_bits[I2C_BIT_SDA]	/* i2c signal */
+#define	SCL		ops->ibo_bits[I2C_BIT_SCL]	/* i2c signal */
+#define	OUTPUT		ops->ibo_bits[I2C_BIT_OUTPUT]	/* SDA is output */
+#define	INPUT		ops->ibo_bits[I2C_BIT_INPUT]	/* SDA is input */
+
+/*ARGSUSED*/
+int
+i2c_bitbang_send_start(void *v, int flags, i2c_bitbang_ops_t ops)
+{
+
+	BB_DIR(OUTPUT);
+
+	BB_SET(SDA | SCL);
+	delay(5);		/* bus free time (4.7 uS) */
+	BB_SET(      SCL);
+	delay(4);		/* start hold time (4.0 uS) */
+	BB_SET(        0);
+	delay(5);		/* clock low time (4.7 uS) */
+
+	return (0);
+}
+
+/*ARGSUSED*/
+int
+i2c_bitbang_send_stop(void *v, int flags, i2c_bitbang_ops_t ops)
+{
+
+	BB_DIR(OUTPUT);
+
+	BB_SET(      SCL);
+	delay(4);		/* stop setup time (4.0 uS) */
+	BB_SET(SDA | SCL);
+
+	return (0);
+}
+
+int
+i2c_bitbang_initiate_xfer(void *v, i2c_addr_t addr, int flags,
+    i2c_bitbang_ops_t ops)
+{
+	int i2caddr;
+
+	/* XXX Only support 7-bit addressing for now. */
+	if ((addr & 0x78) == 0x78)
+		return (EINVAL);
+
+	i2caddr = (addr << 1) | ((flags & I2C_F_READ) ? 1 : 0);
+
+	(void) i2c_bitbang_send_start(v, flags, ops);
+	return (i2c_bitbang_write_byte(v, i2caddr, flags & ~I2C_F_STOP, ops));
+}
+
+int
+i2c_bitbang_read_byte(void *v, uint8_t *valp, int flags,
+    i2c_bitbang_ops_t ops)
+{
+	int i;
+	uint8_t val = 0;
+	uint32_t bit;
+
+	BB_DIR(INPUT);
+	BB_SET(SDA      );
+
+	for (i = 0; i < 8; i++) {
+		val <<= 1;
+		BB_SET(SDA | SCL);
+		delay(4);	/* clock high time (4.0 uS) */
+		if (BB_READ & SDA)
+			val |= 1;
+		BB_SET(SDA      );
+		delay(5);	/* clock low time (4.7 uS) */
+	}
+
+	bit = (flags & I2C_F_LAST) ? SDA : 0;
+	BB_DIR(OUTPUT);
+	BB_SET(bit      );
+	delay(1);	/* data setup time (250 nS) */
+	BB_SET(bit | SCL);
+	delay(4);	/* clock high time (4.0 uS) */
+	BB_SET(bit      );
+	delay(5);	/* clock low time (4.7 uS) */
+
+	BB_DIR(INPUT);
+	BB_SET(SDA      );
+	delay(5);
+
+	if ((flags & (I2C_F_STOP | I2C_F_LAST)) == (I2C_F_STOP | I2C_F_LAST))
+		(void) i2c_bitbang_send_stop(v, flags, ops);
+
+	*valp = val;
+	return (0);
+}
+
+int
+i2c_bitbang_write_byte(void *v, uint8_t val, int flags,
+    i2c_bitbang_ops_t ops)
+{
+	uint32_t bit;
+	uint8_t mask;
+	int error;
+
+	BB_DIR(OUTPUT);
+
+	for (mask = 0x80; mask != 0; mask >>= 1) {
+		bit = (val & mask) ? SDA : 0;
+		BB_SET(bit      );
+		delay(1);	/* data setup time (250 nS) */
+		BB_SET(bit | SCL);
+		delay(4);	/* clock high time (4.0 uS) */
+		BB_SET(bit      );
+		delay(5);	/* clock low time (4.7 uS) */
+	}
+
+	BB_DIR(INPUT);
+
+	BB_SET(SDA      );
+	delay(5);
+	BB_SET(SDA | SCL);
+	delay(4);
+	error = (BB_READ & SDA) ? EIO : 0;
+	BB_SET(SDA      );
+	delay(5);
+
+	if (flags & I2C_F_STOP)
+		(void) i2c_bitbang_send_stop(v, flags, ops);
+
+	return (error);
+}
diff --git a/sys/dev/i2c/i2c_bitbang.h b/sys/dev/i2c/i2c_bitbang.h
new file mode 100644
index 00000000000..a8311bb9daa
--- /dev/null
+++ b/sys/dev/i2c/i2c_bitbang.h
@@ -0,0 +1,63 @@
+/*	$OpenBSD: i2c_bitbang.h,v 1.1 2004/05/23 17:33:43 grange Exp $	*/
+/*	$NetBSD: i2c_bitbang.h,v 1.1 2003/09/30 00:35:31 thorpej Exp $	*/
+
+/*
+ * Copyright (c) 2003 Wasabi Systems, Inc.
+ * All rights reserved.
+ *
+ * Written by Jason R. Thorpe for Wasabi Systems, Inc.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *      This product includes software developed for the NetBSD Project by
+ *      Wasabi Systems, Inc.
+ * 4. The name of Wasabi Systems, Inc. may not be used to endorse
+ *    or promote products derived from this software without specific prior
+ *    written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY WASABI SYSTEMS, INC. ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
+ * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL WASABI SYSTEMS, INC
+ * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef _DEV_I2C_I2C_BITBANG_H_
+#define	_DEV_I2C_I2C_BITBANG_H_
+
+#define	I2C_BIT_SDA		0	/* SDA signal */
+#define	I2C_BIT_SCL		1	/* SCL signal */
+#define	I2C_BIT_OUTPUT		2	/* controller: SDA is output */
+#define	I2C_BIT_INPUT		3	/* controller: SDA is input */
+#define	I2C_NBITS		4
+
+struct i2c_bitbang_ops {
+	void		(*ibo_set_bits)(void *, uint32_t);
+	void		(*ibo_set_dir)(void *, uint32_t);
+	uint32_t	(*ibo_read_bits)(void *);
+	uint32_t	ibo_bits[I2C_NBITS];
+};
+
+typedef const struct i2c_bitbang_ops *i2c_bitbang_ops_t;
+
+int	i2c_bitbang_send_start(void *, int, i2c_bitbang_ops_t);
+int	i2c_bitbang_send_stop(void *, int, i2c_bitbang_ops_t);
+int	i2c_bitbang_initiate_xfer(void *, i2c_addr_t, int, i2c_bitbang_ops_t);
+int	i2c_bitbang_read_byte(void *, uint8_t *, int, i2c_bitbang_ops_t);
+int	i2c_bitbang_write_byte(void *, uint8_t, int, i2c_bitbang_ops_t);
+
+#endif /* _DEV_I2C_I2C_BITBANG_H_ */
diff --git a/sys/dev/i2c/i2c_exec.c b/sys/dev/i2c/i2c_exec.c
new file mode 100644
index 00000000000..f76d17cf949
--- /dev/null
+++ b/sys/dev/i2c/i2c_exec.c
@@ -0,0 +1,157 @@
+/*	$OpenBSD: i2c_exec.c,v 1.1 2004/05/23 17:33:43 grange Exp $	*/
+/*	$NetBSD: i2c_exec.c,v 1.3 2003/10/29 00:34:58 mycroft Exp $	*/
+
+/*
+ * Copyright (c) 2003 Wasabi Systems, Inc.
+ * All rights reserved.
+ *
+ * Written by Jason R. Thorpe for Wasabi Systems, Inc.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *      This product includes software developed for the NetBSD Project by
+ *      Wasabi Systems, Inc.
+ * 4. The name of Wasabi Systems, Inc. may not be used to endorse
+ *    or promote products derived from this software without specific prior
+ *    written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY WASABI SYSTEMS, INC. ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
+ * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL WASABI SYSTEMS, INC
+ * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <sys/param.h>
+#include <sys/systm.h>
+#include <sys/device.h>
+#include <sys/event.h>
+#include <sys/conf.h>
+
+#define	_I2C_PRIVATE
+#include <dev/i2c/i2cvar.h>
+
+/*
+ * iic_exec:
+ *
+ *	Simplified I2C client interface engine.
+ *
+ *	This and the SMBus routines are the preferred interface for
+ *	client access to I2C/SMBus, since many automated controllers
+ *	do not provide access to the low-level primitives of the I2C
+ *	bus protocol.
+ */
+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)
+{
+	const uint8_t *cmd = vcmd;
+	uint8_t *buf = vbuf;
+	int error;
+	size_t len;
+
+	/*
+	 * Defer to the controller if it provides an exec function.  Use
+	 * it if it does.
+	 */
+	if (tag->ic_exec != NULL)
+		return ((*tag->ic_exec)(tag->ic_cookie, op, addr, cmd,
+					cmdlen, buf, buflen, flags));
+
+	if ((len = cmdlen) != 0) {
+		if ((error = iic_initiate_xfer(tag, addr, flags)) != 0)
+			goto bad;
+		while (len--) {
+			if ((error = iic_write_byte(tag, *cmd++, flags)) != 0)
+				goto bad;
+		}
+	}
+
+	if (I2C_OP_READ_P(op))
+		flags |= I2C_F_READ;
+
+	len = buflen;
+	while (len--) {
+		if (len == 0 && I2C_OP_STOP_P(op))
+			flags |= I2C_F_STOP;
+		if (I2C_OP_READ_P(op)) {
+			/* Send REPEATED START. */
+			if ((len + 1) == buflen &&
+			    (error = iic_initiate_xfer(tag, addr, flags)) != 0)
+				goto bad;
+			/* NACK on last byte. */
+			if (len == 0)
+				flags |= I2C_F_LAST;
+			if ((error = iic_read_byte(tag, buf++, flags)) != 0)
+				goto bad;
+		} else  {
+			/* Maybe send START. */
+			if ((len + 1) == buflen && cmdlen == 0 &&
+			    (error = iic_initiate_xfer(tag, addr, flags)) != 0)
+				goto bad;
+			if ((error = iic_write_byte(tag, *buf++, flags)) != 0)
+				goto bad;
+		}
+	}
+
+	return (0);
+ bad:
+	iic_send_stop(tag, flags);
+	return (error);
+}
+
+/*
+ * iic_smbus_write_byte:
+ *
+ *	Perform an SMBus "write byte" operation.
+ */
+int
+iic_smbus_write_byte(i2c_tag_t tag, i2c_addr_t addr, uint8_t cmd,
+    uint8_t val, int flags)
+{
+
+	return (iic_exec(tag, I2C_OP_WRITE_WITH_STOP, addr, &cmd, 1,
+			 &val, 1, flags));
+}
+
+/*
+ * iic_smbus_read_byte:
+ *
+ *	Perform an SMBus "read byte" operation.
+ */
+int
+iic_smbus_read_byte(i2c_tag_t tag, i2c_addr_t addr, uint8_t cmd,
+    uint8_t *valp, int flags)
+{
+
+	return (iic_exec(tag, I2C_OP_READ_WITH_STOP, addr, &cmd, 1,
+			 valp, 1, flags));
+}
+
+/*
+ * iic_smbus_receive_byte:
+ *
+ *	Perform an SMBus "receive byte" operation.
+ */
+int
+iic_smbus_receive_byte(i2c_tag_t tag, i2c_addr_t addr, uint8_t *valp,
+    int flags)
+{
+
+	return (iic_exec(tag, I2C_OP_READ_WITH_STOP, addr, NULL, 0,
+			 valp, 1, flags));
+}
diff --git a/sys/dev/i2c/i2c_io.h b/sys/dev/i2c/i2c_io.h
new file mode 100644
index 00000000000..8a4aea81e12
--- /dev/null
+++ b/sys/dev/i2c/i2c_io.h
@@ -0,0 +1,101 @@
+/*	$OpenBSD: i2c_io.h,v 1.1 2004/05/23 17:33:43 grange Exp $	*/
+/*	$NetBSD: i2c_io.h,v 1.1 2003/09/30 00:35:31 thorpej Exp $	*/
+
+/*
+ * Copyright (c) 2003 Wasabi Systems, Inc.
+ * All rights reserved.
+ *
+ * Written by Jason R. Thorpe for Wasabi Systems, Inc.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *      This product includes software developed for the NetBSD Project by
+ *      Wasabi Systems, Inc.
+ * 4. The name of Wasabi Systems, Inc. may not be used to endorse
+ *    or promote products derived from this software without specific prior
+ *    written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY WASABI SYSTEMS, INC. ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
+ * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL WASABI SYSTEMS, INC
+ * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef _DEV_I2C_I2C_IO_H_
+#define	_DEV_I2C_I2C_IO_H_
+
+#include <sys/ioccom.h>
+
+/* I2C bus address. */
+typedef uint16_t i2c_addr_t;
+
+/* High-level I2C operations. */
+typedef enum {
+	I2C_OP_READ		= 0,
+	I2C_OP_READ_WITH_STOP	= 1,
+	I2C_OP_WRITE		= 2,
+	I2C_OP_WRITE_WITH_STOP	= 3,
+} i2c_op_t;
+
+#define	I2C_OP_READ_P(x)	(((int)(x) & 2) == 0)
+#define	I2C_OP_WRITE_P(x)	(! I2C_OP_READ_P(x))
+#define	I2C_OP_STOP_P(x)	(((int)(x) & 1) != 0)
+
+/*
+ * This structure describes a single I2C control script fragment.
+ *
+ * Note that use of this scripted API allows for support of automated
+ * SMBus controllers.  The following table maps SMBus operations to
+ * script fragment configuration:
+ *
+ *	SMBus "write byte":		I2C_OP_WRITE_WITH_STOP
+ *					cmdlen = 1
+ *
+ *	SMBus "read byte":		I2C_OP_READ_WITH_STOP
+ *					cmdlen = 1
+ *
+ *	SMBus "receive byte":		I2C_OP_READ_WITH_STOP
+ *					cmdlen = 0
+ *
+ * Note that while each of these 3 SMBus operations implies a STOP
+ * (which an automated controller will likely perform automatically),
+ * non-SMBus clients may continue to function even if they issue
+ * I2C_OP_WRITE and I2C_OP_READ.
+ */
+
+#ifdef notyet
+/*
+ * I2C_IOCTL_EXEC:
+ *
+ *	User ioctl to execute an i2c operation.
+ */
+typedef struct i2c_ioctl_exec {
+	i2c_op_t iie_op;		/* operation to perform */
+	i2c_addr_t iie_addr;		/* address of device */
+	const void *iie_cmd;		/* pointer to command */
+	size_t iie_cmdlen;		/* length of command */
+	void *iie_buf;			/* pointer to data buffer */
+	size_t iie_buflen;		/* length of data buffer */
+} i2c_ioctl_exec_t;
+#define	I2C_EXEC_MAX_CMDLEN	32
+#define	I2C_EXEC_MAX_BUFLEN	32
+
+#define	I2C_IOCTL_EXEC		 _IOW('I', 0, i2c_ioctl_exec_t)
+#endif
+
+#endif /* _DEV_I2C_I2C_IO_H_ */
diff --git a/sys/dev/i2c/i2cvar.h b/sys/dev/i2c/i2cvar.h
new file mode 100644
index 00000000000..7065df99932
--- /dev/null
+++ b/sys/dev/i2c/i2cvar.h
@@ -0,0 +1,144 @@
+/*	$OpenBSD: i2cvar.h,v 1.1 2004/05/23 17:33:43 grange Exp $	*/
+/*	$NetBSD: i2cvar.h,v 1.1 2003/09/30 00:35:31 thorpej Exp $	*/
+
+/*
+ * Copyright (c) 2003 Wasabi Systems, Inc.
+ * All rights reserved.
+ *
+ * Written by Steve C. Woodford and Jason R. Thorpe for Wasabi Systems, Inc.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *      This product includes software developed for the NetBSD Project by
+ *      Wasabi Systems, Inc.
+ * 4. The name of Wasabi Systems, Inc. may not be used to endorse
+ *    or promote products derived from this software without specific prior
+ *    written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY WASABI SYSTEMS, INC. ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
+ * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL WASABI SYSTEMS, INC
+ * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef _DEV_I2C_I2CVAR_H_
+#define	_DEV_I2C_I2CVAR_H_
+
+#include <dev/i2c/i2c_io.h>
+
+/* Flags passed to i2c routines. */
+#define	I2C_F_WRITE		0x00	/* new transfer is a write */
+#define	I2C_F_READ		0x01	/* new transfer is a read */
+#define	I2C_F_LAST		0x02	/* last byte of read */
+#define	I2C_F_STOP		0x04	/* send stop after byte */
+#define	I2C_F_POLL		0x08	/* poll, don't sleep */
+
+/*
+ * This structure provides the interface between the i2c framework
+ * and the underlying i2c controller.
+ *
+ * Note that this structure is designed specifically to allow us
+ * to either use the autoconfiguration framework or not.  This
+ * allows a driver for a board with a private i2c bus use generic
+ * i2c client drivers for chips that might be on that board.
+ */
+typedef struct i2c_controller {
+	void	*ic_cookie;		/* controller private */
+
+	/*
+	 * These provide synchronization in the presence of
+	 * multiple users of the i2c bus.  When a device
+	 * driver wishes to perform transfers on the i2c
+	 * bus, the driver should acquire the bus.  When
+	 * the driver is finished, it should release the
+	 * bus.
+	 *
+	 * This is provided by the back-end since a single
+	 * controller may present e.g. i2c and smbus views
+	 * of the same set of i2c wires.
+	 */
+	int	(*ic_acquire_bus)(void *, int);
+	void	(*ic_release_bus)(void *, int);
+
+	/*
+	 * The preferred API for clients of the i2c interface
+	 * is the scripted API.  This handles i2c controllers
+	 * that do not provide raw access to the i2c signals.
+	 */
+	int	(*ic_exec)(void *, i2c_op_t, i2c_addr_t, const void *, size_t,
+		    void *, size_t, int);
+
+	int	(*ic_send_start)(void *, int);
+	int	(*ic_send_stop)(void *, int);
+	int	(*ic_initiate_xfer)(void *, i2c_addr_t, int);
+	int	(*ic_read_byte)(void *, uint8_t *, int);
+	int	(*ic_write_byte)(void *, uint8_t, int);
+} *i2c_tag_t;
+
+/* Used to attach the i2c framework to the controller. */
+struct i2cbus_attach_args {
+	const char *iba_name;		/* bus name ("iic") */
+	i2c_tag_t iba_tag;		/* the controller */
+};
+
+/* Used to attach devices on the i2c bus. */
+struct i2c_attach_args {
+	i2c_tag_t	ia_tag;		/* our controller */
+	i2c_addr_t	ia_addr;	/* address of device */
+	int		ia_size;	/* size (for EEPROMs) */
+};
+
+/*
+ * API presented to i2c controllers.
+ */
+int	iicbus_print(void *, const char *);
+
+#ifdef _I2C_PRIVATE
+/*
+ * Macros used internally by the i2c framework.
+ */
+#define	iic_send_start(ic, flags)					\
+	(*(ic)->ic_send_start)((ic)->ic_cookie, (flags))
+#define	iic_send_stop(ic, flags)					\
+	(*(ic)->ic_send_stop)((ic)->ic_cookie, (flags))
+#define	iic_initiate_xfer(ic, addr, flags)				\
+	(*(ic)->ic_initiate_xfer)((ic)->ic_cookie, (addr), (flags))
+
+#define	iic_read_byte(ic, bytep, flags)					\
+	(*(ic)->ic_read_byte)((ic)->ic_cookie, (bytep), (flags))
+#define	iic_write_byte(ic, byte, flags)					\
+	(*(ic)->ic_write_byte)((ic)->ic_cookie, (byte), (flags))
+#endif /* _I2C_PRIVATE */
+
+/*
+ * Simplified API for clients of the i2c framework.  Definitions
+ * in <dev/i2c/i2c_io.h>.
+ */
+#define	iic_acquire_bus(ic, flags)					\
+	(*(ic)->ic_acquire_bus)((ic)->ic_cookie, (flags))
+#define	iic_release_bus(ic, flags)					\
+	(*(ic)->ic_release_bus)((ic)->ic_cookie, (flags))
+
+int	iic_exec(i2c_tag_t, i2c_op_t, i2c_addr_t, const void *,
+	    size_t, void *, size_t, int);
+
+int	iic_smbus_write_byte(i2c_tag_t, i2c_addr_t, uint8_t, uint8_t, int);
+int	iic_smbus_read_byte(i2c_tag_t, i2c_addr_t, uint8_t, uint8_t *, int);
+int	iic_smbus_receive_byte(i2c_tag_t, i2c_addr_t, uint8_t *, int);
+
+#endif /* _DEV_I2C_I2CVAR_H_ */