[PATCH 09/15] Input: xpad: handle "present" and "gone" correctly

[Pavel Rojtberg <rojtberg@gmail.com>]

From: "Pierre-Loup A. Griffais" <pgriffais@valvesoftware.com>

Handle the "a new device is present" message properly by dynamically
creating the input device at this point in time. This means we now do
not "preallocate" all 4 devices when a single
wireless base station is seen. This requires a workqueue as we are in
interrupt context when we learn about this.

Also properly disconnect any devices that we are told are removed.

Signed-off-by: "Pierre-Loup A. Griffais" <pgriffais@valvesoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Pavel Rojtberg <rojtberg@gmail.com>
---
 drivers/input/joystick/xpad.c | 52 ++++++++++++++++++++++++++++++++++++++++------------
 1 file changed, 40 insertions(+), 12 deletions(-)

diff --git a/drivers/input/joystick/xpad.c b/drivers/input/joystick/xpad.c
index 7d66d77..31bcd78 100644
--- a/drivers/input/joystick/xpad.c
+++ b/drivers/input/joystick/xpad.c
@@ -344,8 +344,12 @@ struct usb_xpad {
 	int xtype;			/* type of xbox device */
 	unsigned long pad_nr;		/* the order x360 pads were attached */
 	const char *name;		/* name of the device */
+	struct work_struct work;	/* init/remove device from callback */
 };
 
+static int xpad_init_input(struct usb_xpad *xpad);
+static void xpad_deinit_input(struct usb_xpad *xpad);
+
 /*
  *	xpad_process_packet
  *
@@ -496,6 +500,22 @@ static void xpad360_process_packet(struct usb_xpad *xpad,
 
 static void xpad_identify_controller(struct usb_xpad *xpad);
 
+static void presence_work_function(struct work_struct *work)
+{
+	struct usb_xpad *xpad = container_of(work, struct usb_xpad, work);
+	int error;
+
+	if (xpad->pad_present) {
+		error = xpad_init_input(xpad);
+		if (error) {
+			/* complain only, not much else we can do here */
+			dev_err(&xpad->dev->dev, "unable to init device\n");
+		}
+	} else {
+		xpad_deinit_input(xpad);
+	}
+}
+
 /*
  * xpad360w_process_packet
  *
@@ -512,13 +532,16 @@ static void xpad_identify_controller(struct usb_xpad *xpad);
  */
 static void xpad360w_process_packet(struct usb_xpad *xpad, u16 cmd, unsigned char *data)
 {
+	int presence;
+
 	/* Presence change */
 	if (data[0] & 0x08) {
-		if (data[1] & 0x80) {
-			xpad->pad_present = 1;
-			xpad_identify_controller(xpad);
-		} else
-			xpad->pad_present = 0;
+		presence = (data[1] & 0x80) != 0;
+
+		if (xpad->pad_present != presence) {
+			xpad->pad_present = presence;
+			schedule_work(&xpad->work);
+		}
 	}
 
 	/* Valid pad data */
@@ -965,8 +988,6 @@ static int xpad_led_probe(struct usb_xpad *xpad)
 		return error;
 	}
 
-	xpad_identify_controller(xpad);
-
 	return 0;
 }
 
@@ -1123,6 +1144,8 @@ static int xpad_init_input(struct usb_xpad *xpad)
 	if (error)
 		goto fail_input_register;
 
+	xpad_identify_controller(xpad);
+
 	return 0;
 
 fail_input_register:
@@ -1187,6 +1210,7 @@ static int xpad_probe(struct usb_interface *intf, const struct usb_device_id *id
 	xpad->mapping = xpad_device[i].mapping;
 	xpad->xtype = xpad_device[i].xtype;
 	xpad->name = xpad_device[i].name;
+	INIT_WORK(&xpad->work, presence_work_function);
 
 	if (xpad->xtype == XTYPE_UNKNOWN) {
 		if (intf->cur_altsetting->desc.bInterfaceClass == USB_CLASS_VENDOR_SPEC) {
@@ -1260,11 +1284,12 @@ static int xpad_probe(struct usb_interface *intf, const struct usb_device_id *id
 		xpad->irq_out->transfer_buffer_length = 12;
 		usb_submit_urb(xpad->irq_out, GFP_KERNEL);
 		mutex_unlock(&xpad->odata_mutex);
+	} else {
+		xpad->pad_present = 1;
+		error = xpad_init_input(xpad);
+		if (error)
+			goto fail4;
 	}
-	xpad->pad_present = 1;
-	error = xpad_init_input(xpad);
-	if (error)
-		goto fail4;
 
 	return 0;
 
@@ -1286,7 +1311,8 @@ static void xpad_disconnect(struct usb_interface *intf)
 {
 	struct usb_xpad *xpad = usb_get_intfdata (intf);
 
-	xpad_deinit_input(xpad);
+	if (xpad->pad_present)
+		xpad_deinit_input(xpad);
 	xpad_deinit_output(xpad);
 
 	if (xpad->xtype == XTYPE_XBOX360W) {
@@ -1297,6 +1323,8 @@ static void xpad_disconnect(struct usb_interface *intf)
 	usb_free_coherent(xpad->udev, XPAD_PKT_LEN,
 			xpad->idata, xpad->idata_dma);
 
+	cancel_work_sync(&xpad->work);
+
 	kfree(xpad);
 
 	usb_set_intfdata(intf, NULL);
-- 
1.9.1