[PATCH v2 2/2] Input: xpad - add wired Beitong BTP-KP20D support

[Aaron Ma <mapengyu@gmail.com>]

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.

Stop any active output URB on probe failure before freeing its URB and
DMA buffer. LED setup may submit the output URB before input
initialization completes.

Signed-off-by: Aaron Ma <mapengyu@gmail.com>
---
Changes in v2:
- Stop the output URB before freeing it on probe failure.

 drivers/input/joystick/xpad.c | 28 +++++++++++++++++++++++++++-
 1 file changed, 27 insertions(+), 1 deletion(-)

diff --git a/drivers/input/joystick/xpad.c b/drivers/input/joystick/xpad.c
index 1616047e65f5e..9adc419066353 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);
@@ -2227,10 +2232,24 @@ 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_stop_output(xpad);
 	xpad_deinit_output(xpad);
 err_free_in_urb:
 	usb_free_urb(xpad->irq_in);
@@ -2247,6 +2266,8 @@ 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 +2309,8 @@ 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 +2332,9 @@ 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