tests: drivers: i2c: twim_instances: add scan i2c test.

Extend twim_instance tests with i2c scan of each bus.
Test checks if there are no unexpected devices detected.

Based on 'scan' command from i2c shell.

Signed-off-by: Bartlomiej Buczek <[email protected]>

Author: nordic-babu

tests/drivers/i2c/twim_instances/src/twim_instances.c

@@ -78,6 +78,32 @@ static void test_configure_instance(const struct device *dev)
 	zassert_equal(-EIO, ret, "%s: i2c_write() failed (%d)", dev->name, ret);
 }
 
+
+/**
+ * Test if any unexpected device can be detected on instance bus.
+ * SMBus and i2c scan shell command based.
+ */
+static void test_scan_instance(const struct device *dev)
+{
+	uint8_t first_addr = 0x00, last_addr = 0x7F;
+	uint8_t dev_cnt = 0;
+
+	struct i2c_msg msg = {
+		.buf   = NULL,
+		.len   = 0U,
+		.flags = I2C_MSG_WRITE | I2C_MSG_STOP
+	};
+
+	for (uint8_t addr = first_addr; addr <= last_addr; addr += 1) {
+		if (i2c_transfer(dev, &msg, 1, addr) == 0) {
+			dev_cnt = dev_cnt + 1;
+		}
+	}
+	zassert_equal(dev_cnt, 0,
+		"i2c scan found %d unexpected devices on %s bus\n",
+		dev_cnt, dev->name);
+}
+
 static bool test_configure_capable(const struct device *dev)
 {
 	return true;
@@ -88,6 +114,11 @@ ZTEST(twim_instances, test_configure)
 	test_all_instances(test_configure_instance, test_configure_capable);
 }
 
+ZTEST(twim_instances, test_scan)
+{
+	test_all_instances(test_scan_instance, test_configure_capable);
+}
+
 static void *suite_setup(void)
 {
 	int i;