[PATCH 2/2] Input: xpad - add wired Beitong BTP-KP20D support

[Aaron Ma]

The wired BTP-KP20D resets itself when its interrupt-IN pipe is idle
for a few seconds, causing periodic re-enumeration whenever no
userspace client holds the input device open. Add a FLAG_KEEPALIVE
quirk that keeps the input URB running from probe to disconnect,
mirroring the XTYPE_XBOX360W URB lifecycle.

The device also needs the MS OS descriptor query to stay in Xbox 360
mode.

Signed-off-by: Aaron Ma <mapengyu@xxxxxxxxx>
---
 drivers/input/joystick/xpad.c | 27 ++++++++++++++++++++++++++-
 1 file changed, 26 insertions(+), 1 deletion(-)

diff --git a/drivers/input/joystick/xpad.c b/drivers/input/joystick/xpad.c
index 1616047e65f5e..5369b880c6a08 100644
--- a/drivers/input/joystick/xpad.c
+++ b/drivers/input/joystick/xpad.c
@@ -73,6 +73,7 @@
 
 #define FLAG_DELAY_INIT BIT(0)
 #define FLAG_MS_OS_DESC BIT(1)
+#define FLAG_KEEPALIVE  BIT(2)
 
 static bool dpad_to_buttons;
 module_param(dpad_to_buttons, bool, S_IRUGO);
@@ -335,6 +336,7 @@ static const struct xpad_device {
 	{ 0x1ee9, 0x1590, "ZOTAC Gaming Zone", 0, XTYPE_XBOX360 },
 	{ 0x20bc, 0x5134, "BETOP BTP-KP50B Xinput Dongle", 0, XTYPE_XBOX360 },
 	{ 0x20bc, 0x514a, "BETOP BTP-KP50C Xinput Dongle", 0, XTYPE_XBOX360 },
+	{ 0x20bc, 0x5158, "Beitong BTP-KP20D Controller", 0, XTYPE_XBOX360, FLAG_MS_OS_DESC | FLAG_KEEPALIVE },
 	{ 0x20bc, 0x5159, "Beitong BTP-KP20D Controller", 0, XTYPE_XBOX360, FLAG_MS_OS_DESC },
 	{ 0x20d6, 0x2001, "BDA Xbox Series X Wired Controller", 0, XTYPE_XBOXONE },
 	{ 0x20d6, 0x2009, "PowerA Enhanced Wired Controller for Xbox Series X|S", 0, XTYPE_XBOXONE },
@@ -780,6 +782,7 @@ struct usb_xpad {
 	time64_t mode_btn_down_ts;
 	bool delay_init;		/* init packets should be delayed */
 	bool delayed_init_done;
+	bool keepalive;			/* int URB must run from probe to disconnect */
 };
 
 static int xpad_init_input(struct usb_xpad *xpad);
@@ -1971,7 +1974,7 @@ static int xpad_init_input(struct usb_xpad *xpad)
 
 	input_set_drvdata(input_dev, xpad);
 
-	if (xpad->xtype != XTYPE_XBOX360W) {
+	if (xpad->xtype != XTYPE_XBOX360W && !xpad->keepalive) {
 		input_dev->open = xpad_open;
 		input_dev->close = xpad_close;
 	}
@@ -2105,6 +2108,8 @@ static int xpad_probe(struct usb_interface *intf, const struct usb_device_id *id
 	xpad->name = xpad_device[i].name;
 	if (xpad_device[i].flags & FLAG_DELAY_INIT)
 		xpad->delay_init = true;
+	if (xpad_device[i].flags & FLAG_KEEPALIVE)
+		xpad->keepalive = true;
 
 	xpad->packet_type = PKT_XB;
 	INIT_WORK(&xpad->work, xpad_presence_work);
@@ -2227,9 +2232,22 @@ static int xpad_probe(struct usb_interface *intf, const struct usb_device_id *id
 		error = xpad_init_input(xpad);
 		if (error)
 			goto err_deinit_output;
+
+		if (xpad->keepalive) {
+			/*
+			 * The device resets itself when the interrupt-IN pipe
+			 * is idle for a few seconds, so keep the URB running
+			 * from probe until disconnect.
+			 */
+			error = xpad_start_input(xpad);
+			if (error)
+				goto err_deinit_input;
+		}
 	}
 	return 0;
 
+err_deinit_input:
+	xpad_deinit_input(xpad);
 err_deinit_output:
 	xpad_deinit_output(xpad);
 err_free_in_urb:
@@ -2247,6 +2265,8 @@ static void xpad_disconnect(struct usb_interface *intf)
 
 	if (xpad->xtype == XTYPE_XBOX360W)
 		xpad360w_stop_input(xpad);
+	else if (xpad->keepalive)
+		xpad_stop_input(xpad);
 
 	xpad_deinit_input(xpad);
 
@@ -2288,6 +2308,8 @@ static int xpad_suspend(struct usb_interface *intf, pm_message_t message)
 		 */
 		if (auto_poweroff && xpad->pad_present)
 			xpad360w_poweroff_controller(xpad);
+	} else if (xpad->keepalive) {
+		xpad_stop_input(xpad);
 	} else {
 		guard(mutex)(&input->mutex);
 
@@ -2309,6 +2331,9 @@ static int xpad_resume(struct usb_interface *intf)
 	if (xpad->xtype == XTYPE_XBOX360W)
 		return xpad360w_start_input(xpad);
 
+	if (xpad->keepalive)
+		return xpad_start_input(xpad);
+
 	guard(mutex)(&input->mutex);
 
 	if (input_device_enabled(input))
-- 
2.53.0