i2c: add diagnostic utility

Change-Id: I7e87457ff6e4210e256f9e41e5555e2d0e1ba20d
Reviewed-on: https://review.haiku-os.org/c/haiku/+/2459
Reviewed-by: Jérôme Duval <jerome.duval@gmail.com>
Reviewed-by: Adrien Destugues <pulkomandy@gmail.com>

src/bin/Jamfile

@@ -251,6 +251,7 @@ SubInclude HAIKU_TOP src bin consoled ;
 SubInclude HAIKU_TOP src bin desklink ;
 SubInclude HAIKU_TOP src bin fwcontrol ;
 SubInclude HAIKU_TOP src bin hid_decode ;
+SubInclude HAIKU_TOP src bin i2c ;
 SubInclude HAIKU_TOP src bin keymap ;
 SubInclude HAIKU_TOP src bin keystore ;
 SubInclude HAIKU_TOP src bin listdev ;

src/bin/i2c/Jamfile

@@ -0,0 +1,7 @@
+SubDir HAIKU_TOP src bin i2c ;
+
+UsePrivateHeaders i2c shared ;
+
+BinCommand <bin>i2c :
+	i2c.cpp
+;

src/bin/i2c/i2c.cpp

@@ -0,0 +1,105 @@
+/*
+ * Copyright 2020, Jérôme Duval, jerome.duval@gmail.com.
+ * Distributed under the terms of the MIT license.
+ */
+
+
+#include <errno.h>
+#include <fcntl.h>
+#include <getopt.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include <Drivers.h>
+
+#include <AutoDeleter.h>
+
+#include "i2c.h"
+
+
+static struct option const kLongOptions[] = {
+	{"help", no_argument, 0, 'h'},
+	{NULL}
+};
+
+
+extern const char *__progname;
+static const char *kProgramName = __progname;
+
+
+void
+usage(int returnValue)
+{
+	fprintf(stderr, "Usage: %s <path-to-i2c-bus-device>\n", kProgramName);
+	exit(returnValue);
+}
+
+
+static int
+scan_bus(const char *path)
+{
+	int err = EXIT_SUCCESS;
+	int fd = open(path, O_RDONLY);
+	if (fd < 0) {
+		fprintf(stderr, "%s: Could not access path: %s\n", kProgramName,
+			strerror(errno));
+		return EXIT_FAILURE;
+	}
+
+	setbuf(stdout, NULL);
+	printf("Scanning I2C bus: %s\n", path);
+	FileDescriptorCloser closer(fd);
+
+	printf("     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f\n");
+	for (int i = 0; i < 128; i+=16) {
+		printf("%02x: ", i);
+		for (int j = 0; j < 16; j++) {
+			uint16 addr = i + j;
+			uint8 cmd = 0;
+			uint8 data = 0;
+			i2c_ioctl_exec exec;
+			exec.addr = addr;
+			exec.op = I2C_OP_READ_STOP;
+			exec.cmdBuffer = &cmd;
+			exec.cmdLength = sizeof(cmd);
+			exec.buffer = &data;
+			exec.bufferLength = sizeof(data);
+			if (ioctl(fd, I2CEXEC, &exec, sizeof(exec)) == 0)
+				printf("%02x ", addr);
+			else
+				printf("-- ");
+		}
+		printf("\n");
+	}
+
+	close(fd);
+
+	return err;
+}
+
+
+int
+main(int argc, char** argv)
+{
+	int c;
+	while ((c = getopt_long(argc, argv, "h", kLongOptions, NULL)) != -1) {
+		switch (c) {
+			case 0:
+				break;
+			case 'h':
+				usage(0);
+				break;
+			default:
+				usage(1);
+				break;
+		}
+	}
+
+	if (argc - optind < 1)
+		usage(1);
+	const char* path = argv[optind++];
+
+	exit(scan_bus(path));
+}