--- /dev/null
+.\" $NetBSD: i2cscan.8,v 1.3 2013/07/10 15:18:54 tcort Exp $
+.\"
+.\" Copyright (c) 2011, 2013 The NetBSD Foundation, Inc.
+.\" All rights reserved.
+.\"
+.\" This code is derived from software contributed to The NetBSD Foundation
+.\" by Thomas Klausner.
+.\"
+.\" 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.
+.\"
+.\" THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
+.\" ``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 THE FOUNDATION OR CONTRIBUTORS
+.\" 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.
+.\"
+.Dd July 10, 2013
+.Dt I2CSCAN 8
+.Os
+.Sh NAME
+.Nm i2cscan
+.Nd scan an IIC bus for devices
+.Sh SYNOPSIS
+.Nm
+.Op Fl r
+.Ar i2cdev
+.Sh DESCRIPTION
+The
+.Nm
+utility scans the IIC bus
+.Pq Xr iic 4
+specified by
+.Ar i2cdev
+to determine which addresses respond.
+.Pp
+Available options:
+.Bl -tag -width Ds
+.It Fl r
+scan using 1 byte reads instead of quick writes.
+.El
+.Pp
+.Em WARNING !
+Using this utility can access some devices in such a
+manner as to leave them in an unstable or unusable state.
+It can also lock up the entire
+.Xr iic 4
+bus.
+Don't use this utility unless you know what you're doing and can
+accept all sorts of unforeseen consequences.
+.Sh EXIT STATUS
+.Ex -std i2cscan
+.Sh SEE ALSO
+.Xr iic 4
--- /dev/null
+/* $NetBSD: i2cscan.c,v 1.4 2013/07/10 15:18:54 tcort Exp $ */
+
+/*-
+ * Copyright (c) 2011, 2013 The NetBSD Foundation, Inc.
+ * All rights reserved.
+ *
+ * This code is derived from software contributed to The NetBSD Foundation
+ * by Paul Goyette and Jared McNeill
+ *
+ * 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.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
+ * ``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 THE FOUNDATION OR CONTRIBUTORS
+ * 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/cdefs.h>
+__RCSID("$NetBSD: i2cscan.c,v 1.4 2013/07/10 15:18:54 tcort Exp $");
+
+#include <sys/types.h>
+#include <sys/ioctl.h>
+
+#include <err.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+#include <dev/i2c/i2c_io.h>
+
+#define MODE_DEFAULT 0
+#define MODE_READ 1
+
+__dead static void
+usage(void)
+{
+ fprintf(stderr, "usage: %s [-r] <i2cdev>\n", getprogname());
+ exit(EXIT_FAILURE);
+}
+
+static int
+iic_smbus_quick_write(int fd, i2c_addr_t addr, int flags)
+{
+ i2c_ioctl_exec_t iie;
+
+ iie.iie_op = I2C_OP_WRITE_WITH_STOP;
+ iie.iie_addr = addr;
+ iie.iie_cmd = NULL;
+ iie.iie_cmdlen = 0;
+ iie.iie_buf = NULL;
+ iie.iie_buflen = 0;
+
+ if (ioctl(fd, I2C_IOCTL_EXEC, &iie) == -1)
+ return errno;
+ return 0;
+}
+
+static int
+iic_smbus_receive_byte(int fd, i2c_addr_t addr, uint8_t *valp, int flags)
+{
+ i2c_ioctl_exec_t iie;
+
+ iie.iie_op = I2C_OP_READ_WITH_STOP;
+ iie.iie_addr = addr;
+ iie.iie_cmd = NULL;
+ iie.iie_cmdlen = 0;
+ iie.iie_buf = valp;
+ iie.iie_buflen = 1;
+
+ if (ioctl(fd, I2C_IOCTL_EXEC, &iie) == -1)
+ return errno;
+ return 0;
+
+}
+
+static void
+do_i2c_scan(const char *dname, int fd, int mode)
+{
+ int error;
+ int found = 0;
+ i2c_addr_t addr;
+ uint8_t val;
+
+ for (addr = 0x09; addr < 0x78; addr++) {
+ /*
+ * Skip certain i2c addresses:
+ * 0x00 General Call / START
+ * 0x01 CBUS Address
+ * 0x02 Different Bus format
+ * 0x03 - 0x07 Reserved
+ * 0x08 Host Address
+ * 0x0c Alert Response Address
+ * 0x28 ACCESS.Bus host
+ * 0x37 ACCESS.Bus default address
+ * 0x48 - 0x4b Prototypes
+ * 0x61 Device Default Address
+ * 0x78 - 0x7b 10-bit addresses
+ * 0x7c - 0x7f Reserved
+ *
+ * Some of these are skipped by judicious selection
+ * of the range of the above for (;;) statement.
+ *
+ * if (addr <= 0x08 || addr >= 0x78)
+ * continue;
+ */
+ if (addr == 0x0c || addr == 0x28 || addr == 0x37 ||
+ addr == 0x61 || (addr & 0x7c) == 0x48)
+ continue;
+
+ /*
+ * Use SMBus quick_write command to detect most
+ * addresses; should avoid hanging the bus on
+ * some write-only devices (like clocks that show
+ * up at address 0x69)
+ *
+ * XXX The quick_write() is allegedly known to
+ * XXX corrupt the Atmel AT24RF08 EEPROM found
+ * XXX on some IBM Thinkpads!
+ */
+ printf("\r%s: scanning 0x%02x", dname, addr);
+ fflush(stdout);
+ if ((addr & 0xf8) == 0x30 ||
+ (addr & 0xf0) == 0x50 ||
+ mode == MODE_READ)
+ error = iic_smbus_receive_byte(fd, addr, &val, 0);
+ else
+ error = iic_smbus_quick_write(fd, addr, 0);
+ if (error == 0) {
+ printf("\r%s: found device at 0x%02x\n",
+ dname, addr);
+ ++found;
+ }
+ }
+ if (found == 0)
+ printf("\r%s: no devices found\n", dname);
+ else
+ printf("\r%s: %d devices found\n", dname, found);
+}
+
+int
+main(int argc, char *argv[])
+{
+ int fd;
+ int ch, rflag;
+ int mode;
+
+ setprogname(*argv);
+
+ rflag = 0;
+
+ while ((ch = getopt(argc, argv, "r")) != -1)
+ switch (ch) {
+ case 'r':
+ rflag = 1;
+ break;
+ default:
+ break;
+ }
+ argv += optind;
+ argc -= optind;
+
+ if (rflag)
+ mode = MODE_READ;
+ else
+ mode = MODE_DEFAULT;
+
+ if (*argv == NULL)
+ usage();
+
+ fd = open(*argv, O_RDWR);
+ if (fd == -1)
+ err(EXIT_FAILURE, "couldn't open %s", *argv);
+
+ do_i2c_scan(*argv, fd, mode);
+
+ close(fd);
+
+ return EXIT_SUCCESS;
+}