[RESEND] HID: i2c-hid: fix handling of unpopulated devices

diff --git a/drivers/hid/i2c-hid/i2c-hid-core.c b/drivers/hid/i2c-hid/i2c-hid-core.c
index 9601c0605fd9..e66c058a4b00 100644
--- a/drivers/hid/i2c-hid/i2c-hid-core.c
+++ b/drivers/hid/i2c-hid/i2c-hid-core.c
@@ -998,45 +998,29 @@  static int i2c_hid_core_resume(struct i2c_hid *ihid)
 	return hid_driver_reset_resume(hid);
 }
 
-/**
- * __do_i2c_hid_core_initial_power_up() - First time power up of the i2c-hid device.
- * @ihid: The ihid object created during probe.
- *
- * This function is called at probe time.
- *
- * The initial power on is where we do some basic validation that the device
- * exists, where we fetch the HID descriptor, and where we create the actual
- * HID devices.
- *
- * Return: 0 or error code.
+/*
+ * Check that the device exists and parse the HID descriptor.
  */
-static int __do_i2c_hid_core_initial_power_up(struct i2c_hid *ihid)
+static int __i2c_hid_core_probe(struct i2c_hid *ihid)
 {
 	struct i2c_client *client = ihid->client;
 	struct hid_device *hid = ihid->hid;
 	int ret;
 
-	ret = i2c_hid_core_power_up(ihid);
-	if (ret)
-		return ret;
-
 	/* Make sure there is something at this address */
 	ret = i2c_smbus_read_byte(client);
 	if (ret < 0) {
 		i2c_hid_dbg(ihid, "nothing at this address: %d\n", ret);
-		ret = -ENXIO;
-		goto err;
+		return -ENXIO;
 	}
 
 	ret = i2c_hid_fetch_hid_descriptor(ihid);
 	if (ret < 0) {
 		dev_err(&client->dev,
 			"Failed to fetch the HID Descriptor\n");
-		goto err;
+		return ret;
 	}
 
-	enable_irq(client->irq);
-
 	hid->version = le16_to_cpu(ihid->hdesc.bcdVersion);
 	hid->vendor = le16_to_cpu(ihid->hdesc.wVendorID);
 	hid->product = le16_to_cpu(ihid->hdesc.wProductID);
@@ -1050,17 +1034,49 @@  static int __do_i2c_hid_core_initial_power_up(struct i2c_hid *ihid)
 
 	ihid->quirks = i2c_hid_lookup_quirk(hid->vendor, hid->product);
 
+	return 0;
+}
+
+static int i2c_hid_core_register_hid(struct i2c_hid *ihid)
+{
+	struct i2c_client *client = ihid->client;
+	struct hid_device *hid = ihid->hid;
+	int ret;
+
+	enable_irq(client->irq);
+
 	ret = hid_add_device(hid);
 	if (ret) {
 		if (ret != -ENODEV)
 			hid_err(client, "can't add hid device: %d\n", ret);
-		goto err;
+		disable_irq(client->irq);
+		return ret;
 	}
 
 	return 0;
+}
+
+static int i2c_hid_core_probe_panel_follower(struct i2c_hid *ihid)
+{
+	int ret;
 
-err:
+	ret = i2c_hid_core_power_up(ihid);
+	if (ret)
+		return ret;
+
+	ret = __i2c_hid_core_probe(ihid);
+	if (ret)
+		goto err_power_down;
+
+	ret = i2c_hid_core_register_hid(ihid);
+	if (ret)
+		goto err_power_down;
+
+	return 0;
+
+err_power_down:
 	i2c_hid_core_power_down(ihid);
+
 	return ret;
 }
 
@@ -1077,7 +1093,7 @@  static void ihid_core_panel_prepare_work(struct work_struct *work)
 	 * steps.
 	 */
 	if (!hid->version)
-		ret = __do_i2c_hid_core_initial_power_up(ihid);
+		ret = i2c_hid_core_probe_panel_follower(ihid);
 	else
 		ret = i2c_hid_core_resume(ihid);
 
@@ -1156,30 +1172,6 @@  static int i2c_hid_core_register_panel_follower(struct i2c_hid *ihid)
 	return 0;
 }
 
-static int i2c_hid_core_initial_power_up(struct i2c_hid *ihid)
-{
-	/*
-	 * If we're a panel follower, we'll register and do our initial power
-	 * up when the panel turns on; otherwise we do it right away.
-	 */
-	if (drm_is_panel_follower(&ihid->client->dev))
-		return i2c_hid_core_register_panel_follower(ihid);
-	else
-		return __do_i2c_hid_core_initial_power_up(ihid);
-}
-
-static void i2c_hid_core_final_power_down(struct i2c_hid *ihid)
-{
-	/*
-	 * If we're a follower, the act of unfollowing will cause us to be
-	 * powered down. Otherwise we need to manually do it.
-	 */
-	if (ihid->is_panel_follower)
-		drm_panel_remove_follower(&ihid->panel_follower);
-	else
-		i2c_hid_core_suspend(ihid, true);
-}
-
 int i2c_hid_core_probe(struct i2c_client *client, struct i2chid_ops *ops,
 		       u16 hid_descriptor_address, u32 quirks)
 {
@@ -1224,14 +1216,10 @@  int i2c_hid_core_probe(struct i2c_client *client, struct i2chid_ops *ops,
 		return ret;
 	device_enable_async_suspend(&client->dev);
 
-	ret = i2c_hid_init_irq(client);
-	if (ret < 0)
-		goto err_buffers_allocated;
-
 	hid = hid_allocate_device();
 	if (IS_ERR(hid)) {
 		ret = PTR_ERR(hid);
-		goto err_irq;
+		goto err_free_buffers;
 	}
 
 	ihid->hid = hid;
@@ -1242,19 +1230,42 @@  int i2c_hid_core_probe(struct i2c_client *client, struct i2chid_ops *ops,
 	hid->bus = BUS_I2C;
 	hid->initial_quirks = quirks;
 
-	ret = i2c_hid_core_initial_power_up(ihid);
+	/* Power on and probe unless device is a panel follower. */
+	if (!drm_is_panel_follower(&ihid->client->dev)) {
+		ret = i2c_hid_core_power_up(ihid);
+		if (ret < 0)
+			goto err_destroy_device;
+
+		ret = __i2c_hid_core_probe(ihid);
+		if (ret < 0)
+			goto err_power_down;
+	}
+
+	ret = i2c_hid_init_irq(client);
+	if (ret < 0)
+		goto err_power_down;
+
+	/*
+	 * If we're a panel follower, we'll register when the panel turns on;
+	 * otherwise we do it right away.
+	 */
+	if (drm_is_panel_follower(&ihid->client->dev))
+		ret = i2c_hid_core_register_panel_follower(ihid);
+	else
+		ret = i2c_hid_core_register_hid(ihid);
 	if (ret)
-		goto err_mem_free;
+		goto err_free_irq;
 
 	return 0;
 
-err_mem_free:
-	hid_destroy_device(hid);
-
-err_irq:
+err_free_irq:
 	free_irq(client->irq, ihid);
-
-err_buffers_allocated:
+err_power_down:
+	if (!drm_is_panel_follower(&ihid->client->dev))
+		i2c_hid_core_power_down(ihid);
+err_destroy_device:
+	hid_destroy_device(hid);
+err_free_buffers:
 	i2c_hid_free_buffers(ihid);
 
 	return ret;
@@ -1266,7 +1277,14 @@  void i2c_hid_core_remove(struct i2c_client *client)
 	struct i2c_hid *ihid = i2c_get_clientdata(client);
 	struct hid_device *hid;
 
-	i2c_hid_core_final_power_down(ihid);
+	/*
+	 * If we're a follower, the act of unfollowing will cause us to be
+	 * powered down. Otherwise we need to manually do it.
+	 */
+	if (ihid->is_panel_follower)
+		drm_panel_remove_follower(&ihid->panel_follower);
+	else
+		i2c_hid_core_suspend(ihid, true);
 
 	hid = ihid->hid;
 	hid_destroy_device(hid);