platform/chrome: cros_ec: fix error handling in cros_ec_register()

Fix cros_ec_register() to unregister platform devices if
blocking_notifier_chain_register() fails.

Also use the single exit path to handle the platform device
unregistration.

Fixes: 42cd0ab4 ("platform/chrome: cros_ec: Query EC protocol version if EC transitions between RO/RW")
Reviewed-by: NPrashant Malani <pmalani@chromium.org>
Signed-off-by: NTzung-Bi Shih <tzungbi@kernel.org>

drivers/platform/chrome/cros_ec.c

@@ -189,6 +189,8 @@ int cros_ec_register(struct cros_ec_device *ec_dev)
 	ec_dev->max_request = sizeof(struct ec_params_hello);
 	ec_dev->max_response = sizeof(struct ec_response_get_protocol_info);
 	ec_dev->max_passthru = 0;
+	ec_dev->ec = NULL;
+	ec_dev->pd = NULL;
 
 	ec_dev->din = devm_kzalloc(dev, ec_dev->din_size, GFP_KERNEL);
 	if (!ec_dev->din)
@@ -245,18 +247,16 @@ int cros_ec_register(struct cros_ec_device *ec_dev)
 		if (IS_ERR(ec_dev->pd)) {
 			dev_err(ec_dev->dev,
 				"Failed to create CrOS PD platform device\n");
-			platform_device_unregister(ec_dev->ec);
-			return PTR_ERR(ec_dev->pd);
+			err = PTR_ERR(ec_dev->pd);
+			goto exit;
 		}
 	}
 
 	if (IS_ENABLED(CONFIG_OF) && dev->of_node) {
 		err = devm_of_platform_populate(dev);
 		if (err) {
-			platform_device_unregister(ec_dev->pd);
-			platform_device_unregister(ec_dev->ec);
 			dev_err(dev, "Failed to register sub-devices\n");
-			return err;
+			goto exit;
 		}
 	}
 
@@ -278,7 +278,7 @@ int cros_ec_register(struct cros_ec_device *ec_dev)
 		err = blocking_notifier_chain_register(&ec_dev->event_notifier,
 						      &ec_dev->notifier_ready);
 		if (err)
-			return err;
+			goto exit;
 	}
 
 	dev_info(dev, "Chrome EC device registered\n");
@@ -291,6 +291,10 @@ int cros_ec_register(struct cros_ec_device *ec_dev)
 		cros_ec_irq_thread(0, ec_dev);
 
 	return 0;
+exit:
+	platform_device_unregister(ec_dev->ec);
+	platform_device_unregister(ec_dev->pd);
+	return err;
 }
 EXPORT_SYMBOL(cros_ec_register);