test/avocado/machine_aspeed.py: Add I2C tests to ast2500-evb

Create a named I2C temperature sensor device on the command line,
instantiate device from Linux since it is not part of the device tree,
and check the temperature is correctly reported under sysfs.

Signed-off-by: Cédric Le Goater <clg@kaod.org>

tests/avocado/machine_aspeed.py

@@ -119,7 +119,20 @@ class AST2x00Machine(QemuSystemTest):
         image_path = self.fetch_asset(image_url, asset_hash=image_hash,
                                       algorithm='sha256')
 
+        self.vm.add_args('-device',
+                         'tmp105,bus=aspeed.i2c.bus.3,address=0x4d,id=tmp-test');
         self.do_test_arm_aspeed_buidroot_start(image_path, '0x0')
+
+        exec_command_and_wait_for_pattern(self,
+             'echo lm75 0x4d > /sys/class/i2c-dev/i2c-3/device/new_device',
+             'i2c i2c-3: new_device: Instantiated device lm75 at 0x4d');
+        exec_command_and_wait_for_pattern(self,
+                             'cat /sys/class/hwmon/hwmon1/temp1_input', '0')
+        self.vm.command('qom-set', path='/machine/peripheral/tmp-test',
+                        property='temperature', value=18000);
+        exec_command_and_wait_for_pattern(self,
+                             'cat /sys/class/hwmon/hwmon1/temp1_input', '18000')
+
         self.do_test_arm_aspeed_buidroot_poweroff()
 
     def test_arm_ast2600_evb_builroot(self):