Input: wacom - create inputs when wireless connect

When a tablet connect or disconnect is detected, schedule
work queue to register or unregister related input devices.

When a wireless tablet connects, it reports same USB PID
used if tablet is connected with USB cable. Use this to
update features values, set input capabilities, and then
register device. From there, the Pen and Touch interfaces
will reuse the existing tablet's IRQ routines.

Its possible that 1 receiver is shared with 2 tablets with
different PID (small and medium Bamboo for example) so the
input is unregister at disconnect to better support this case.

Signed-off-by: Chris Bagwell <[e-mail]>
Tested-by: Jason Gerecke <[e-mail]>
Acked-by: Ping Cheng <[e-mail]>
Signed-off-by: Dmitry Torokhov <[e-mail]>

drivers/input/tablet/wacom.h

···
 	struct urb *irq;
 	struct wacom_wac wacom_wac;
 	struct mutex lock;
+	struct work_struct work;
 	bool open;
 	char phys[32];
 	struct wacom_led {
···
 		u8 img_lum;   /* OLED matrix display brightness */
 	} led;
 };
+
+static inline void wacom_schedule_work(struct wacom_wac *wacom_wac)
+{
+	struct wacom *wacom = container_of(wacom_wac, struct wacom, wacom_wac);
+	schedule_work(&wacom->work);
+}
 
 extern const struct usb_device_id wacom_ids[];
 

drivers/input/tablet/wacom_sys.c

···
 		usb_autopm_put_interface(wacom->intf);
 }
 
+/*
+ * Static values for max X/Y and resolution of Pen interface is stored in
+ * features. This mean physical size of active area can be computed.
+ * This is useful to do when Pen and Touch have same active area of tablet.
+ * This means for Touch device, we only need to find max X/Y value and we
+ * have enough information to compute resolution of touch.
+ */
+static void wacom_set_phy_from_res(struct wacom_features *features)
+{
+	features->x_phy = (features->x_max * 100) / features->x_resolution;
+	features->y_phy = (features->y_max * 100) / features->y_resolution;
+}
+
 static int wacom_parse_logical_collection(unsigned char *report,
 					  struct wacom_features *features)
 {
···
 		features->pktlen = WACOM_PKGLEN_BBTOUCH3;
 		features->device_type = BTN_TOOL_FINGER;
 
-		/*
-		 * Stylus and Touch have same active area
-		 * so compute physical size based on stylus
-		 * data before its overwritten.
-		 */
-		features->x_phy =
-			(features->x_max * features->x_resolution) / 100;
-		features->y_phy =
-			(features->y_max * features->y_resolution) / 100;
+		wacom_set_phy_from_res(features);
 
 		features->x_max = features->y_max =
 			get_unaligned_le16(&report[10]);
···
 	return error;
 }
 
+static void wacom_wireless_work(struct work_struct *work)
+{
+	struct wacom *wacom = container_of(work, struct wacom, work);
+	struct usb_device *usbdev = wacom->usbdev;
+	struct wacom_wac *wacom_wac = &wacom->wacom_wac;
+
+	/*
+	 * Regardless if this is a disconnect or a new tablet,
+	 * remove any existing input devices.
+	 */
+
+	/* Stylus interface */
+	wacom = usb_get_intfdata(usbdev->config->interface[1]);
+	if (wacom->wacom_wac.input)
+		input_unregister_device(wacom->wacom_wac.input);
+	wacom->wacom_wac.input = 0;
+
+	/* Touch interface */
+	wacom = usb_get_intfdata(usbdev->config->interface[2]);
+	if (wacom->wacom_wac.input)
+		input_unregister_device(wacom->wacom_wac.input);
+	wacom->wacom_wac.input = 0;
+
+	if (wacom_wac->pid == 0) {
+		printk(KERN_INFO "wacom: wireless tablet disconnected\n");
+	} else {
+		const struct usb_device_id *id = wacom_ids;
+
+		printk(KERN_INFO
+		       "wacom: wireless tablet connected with PID %x\n",
+		       wacom_wac->pid);
+
+		while (id->match_flags) {
+			if (id->idVendor == USB_VENDOR_ID_WACOM &&
+			    id->idProduct == wacom_wac->pid)
+				break;
+			id++;
+		}
+
+		if (!id->match_flags) {
+			printk(KERN_INFO
+			       "wacom: ignorning unknown PID.\n");
+			return;
+		}
+
+		/* Stylus interface */
+		wacom = usb_get_intfdata(usbdev->config->interface[1]);
+		wacom_wac = &wacom->wacom_wac;
+		wacom_wac->features =
+			*((struct wacom_features *)id->driver_info);
+		wacom_wac->features.device_type = BTN_TOOL_PEN;
+		wacom_register_input(wacom);
+
+		/* Touch interface */
+		wacom = usb_get_intfdata(usbdev->config->interface[2]);
+		wacom_wac = &wacom->wacom_wac;
+		wacom_wac->features =
+			*((struct wacom_features *)id->driver_info);
+		wacom_wac->features.pktlen = WACOM_PKGLEN_BBTOUCH3;
+		wacom_wac->features.device_type = BTN_TOOL_FINGER;
+		wacom_set_phy_from_res(&wacom_wac->features);
+		wacom_wac->features.x_max = wacom_wac->features.y_max = 4096;
+		wacom_register_input(wacom);
+	}
+}
+
 static int wacom_probe(struct usb_interface *intf, const struct usb_device_id *id)
 {
 	struct usb_device *dev = interface_to_usbdev(intf);
···
 	wacom->usbdev = dev;
 	wacom->intf = intf;
 	mutex_init(&wacom->lock);
+	INIT_WORK(&wacom->work, wacom_wireless_work);
 	usb_make_path(dev, wacom->phys, sizeof(wacom->phys));
 	strlcat(wacom->phys, "/input0", sizeof(wacom->phys));
 
···
 	usb_set_intfdata(intf, NULL);
 
 	usb_kill_urb(wacom->irq);
+	cancel_work_sync(&wacom->work);
 	if (wacom->wacom_wac.input)
 		input_unregister_device(wacom->wacom_wac.input);
 	wacom_destroy_leds(wacom);

drivers/input/tablet/wacom_wac.c

···
 
 static int wacom_wireless_irq(struct wacom_wac *wacom, size_t len)
 {
-	if (len != WACOM_PKGLEN_WIRELESS)
+	unsigned char *data = wacom->data;
+	int connected;
+
+	if (len != WACOM_PKGLEN_WIRELESS || data[0] != 0x80)
 		return 0;
+
+	connected = data[1] & 0x01;
+	if (connected) {
+		int pid;
+
+		pid = get_unaligned_be16(&data[6]);
+		if (wacom->pid != pid) {
+			wacom->pid = pid;
+			wacom_schedule_work(wacom);
+		}
+	} else if (wacom->pid != 0) {
+		/* disconnected while previously connected */
+		wacom->pid = 0;
+		wacom_schedule_work(wacom);
+	}
 
 	return 0;
 }

drivers/input/tablet/wacom_wac.h

···
 	struct wacom_features features;
 	struct wacom_shared *shared;
 	struct input_dev *input;
+	int pid;
 };
 
 #endif