1 files changed, 89 insertions, 0 deletions

diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c
index 04cee65531d7..f93dd6f48a79 100644
--- a/drivers/hid/hid-core.c
+++ b/drivers/hid/hid-core.c
@@ -1750,6 +1750,94 @@ void hid_disconnect(struct hid_device *hdev)
 }
 EXPORT_SYMBOL_GPL(hid_disconnect);
 
+/**
+ * hid_hw_start - start underlying HW
+ * @hdev: hid device
+ * @connect_mask: which outputs to connect, see HID_CONNECT_*
+ *
+ * Call this in probe function *after* hid_parse. This will setup HW
+ * buffers and start the device (if not defeirred to device open).
+ * hid_hw_stop must be called if this was successful.
+ */
+int hid_hw_start(struct hid_device *hdev, unsigned int connect_mask)
+{
+	int error;
+
+	error = hdev->ll_driver->start(hdev);
+	if (error)
+		return error;
+
+	if (connect_mask) {
+		error = hid_connect(hdev, connect_mask);
+		if (error) {
+			hdev->ll_driver->stop(hdev);
+			return error;
+		}
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(hid_hw_start);
+
+/**
+ * hid_hw_stop - stop underlying HW
+ * @hdev: hid device
+ *
+ * This is usually called from remove function or from probe when something
+ * failed and hid_hw_start was called already.
+ */
+void hid_hw_stop(struct hid_device *hdev)
+{
+	hid_disconnect(hdev);
+	hdev->ll_driver->stop(hdev);
+}
+EXPORT_SYMBOL_GPL(hid_hw_stop);
+
+/**
+ * hid_hw_open - signal underlying HW to start delivering events
+ * @hdev: hid device
+ *
+ * Tell underlying HW to start delivering events from the device.
+ * This function should be called sometime after successful call
+ * to hid_hiw_start().
+ */
+int hid_hw_open(struct hid_device *hdev)
+{
+	int ret;
+
+	ret = mutex_lock_killable(&hdev->ll_open_lock);
+	if (ret)
+		return ret;
+
+	if (!hdev->ll_open_count++) {
+		ret = hdev->ll_driver->open(hdev);
+		if (ret)
+			hdev->ll_open_count--;
+	}
+
+	mutex_unlock(&hdev->ll_open_lock);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(hid_hw_open);
+
+/**
+ * hid_hw_close - signal underlaying HW to stop delivering events
+ *
+ * @hdev: hid device
+ *
+ * This function indicates that we are not interested in the events
+ * from this device anymore. Delivery of events may or may not stop,
+ * depending on the number of users still outstanding.
+ */
+void hid_hw_close(struct hid_device *hdev)
+{
+	mutex_lock(&hdev->ll_open_lock);
+	if (!--hdev->ll_open_count)
+		hdev->ll_driver->close(hdev);
+	mutex_unlock(&hdev->ll_open_lock);
+}
+EXPORT_SYMBOL_GPL(hid_hw_close);
+
 /*
  * A list of devices for which there is a specialized driver on HID bus.
  *
@@ -2747,6 +2835,7 @@ struct hid_device *hid_allocate_device(void)
 	spin_lock_init(&hdev->debug_list_lock);
 	sema_init(&hdev->driver_lock, 1);
 	sema_init(&hdev->driver_input_lock, 1);
+	mutex_init(&hdev->ll_open_lock);
 
 	return hdev;
 }