[PATCH v4 1/1] HID:hid-multitouch: Add ELAN production request when resume.

Add ELAN production request when resume.

Some Elan legacy devices require SET_IDLE to be set on resume.
It should be safe to send it to other devices too.
Tested on 3M, Stantum, Cypress, Zytronic, eGalax, and Elan panels. 


Signed-off-by: Scott Liu <redacted>
Suggested-off-by: Benjamin Tissoires [off-list ref]
---
 drivers/hid/hid-multitouch.c |   27 +++++++++++++++++++++++++++
 1 file changed, 27 insertions(+)

diff --git a/drivers/hid/hid-multitouch.c b/drivers/hid/hid-multitouch.c
index 59c8b5c..e824c37 100644
--- a/drivers/hid/hid-multitouch.c
+++ b/drivers/hid/hid-multitouch.c

@@ -767,6 +767,32 @@ static int mt_reset_resume(struct hid_device *hdev)
 	mt_set_input_mode(hdev);
 	return 0;
 }
+
+static int mt_resume(struct hid_device *hdev)
+{
+	struct usb_interface *intf;
+	struct usb_host_interface *interface;
+	struct usb_device *dev;
+
+	if (hdev->bus != BUS_USB)
+		return 0;
+
+	intf = to_usb_interface(hdev->dev.parent);
+	interface = intf->cur_altsetting;
+	dev = hid_to_usb_dev(hdev);
+
+	/* Some Elan legacy devices require SET_IDLE to be set on resume.
+	 * It should be safe to send it to other devices too.
+	 * Tested on 3M, Stantum, Cypress, Zytronic, eGalax, and Elan panels. */
+
+	usb_control_msg(dev, usb_sndctrlpipe(dev, 0),
+			HID_REQ_SET_IDLE,
+			USB_TYPE_CLASS | USB_RECIP_INTERFACE,
+			0, interface->desc.bInterfaceNumber,
+			NULL, 0, USB_CTRL_SET_TIMEOUT);
+
+	return 0;
+}
 #endif
 
 static void mt_remove(struct hid_device *hdev)

@@ -1092,6 +1118,7 @@ static struct hid_driver mt_driver = {
 	.event = mt_event,
 #ifdef CONFIG_PM
 	.reset_resume = mt_reset_resume,
+	.resume = mt_resume,
 #endif
 };