[PATCH v1] xen/input: add multi-touch support

[Oleksandr Andrushchenko <andr2000@gmail.com>]

From: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>

Extend xen_kbdfront to provide multi-touch support
to unprivileged domains.

Signed-off-by: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>

---
Changes since initial:
 - use input_set_capability instead of setting flags directly
 - input_mt_init_slots: let userspace better chance of figuring
   how to handle the device: use INPUT_MT_DIRECT,
   drop INPUT_MT_DROP_UNUSED
 - add error handling for input_mt_init_slots
 - remove module paramters
 - remove odd unlikely
---
 drivers/input/misc/xen-kbdfront.c | 135 +++++++++++++++++++++++++++++++++++++-
 1 file changed, 133 insertions(+), 2 deletions(-)

diff --git a/drivers/input/misc/xen-kbdfront.c b/drivers/input/misc/xen-kbdfront.c
index eb770613a9bd..9fa005038773 100644
--- a/drivers/input/misc/xen-kbdfront.c
+++ b/drivers/input/misc/xen-kbdfront.c
@@ -17,6 +17,7 @@
 #include <linux/errno.h>
 #include <linux/module.h>
 #include <linux/input.h>
+#include <linux/input/mt.h>
 #include <linux/slab.h>
 
 #include <asm/xen/hypervisor.h>
@@ -34,11 +35,14 @@
 struct xenkbd_info {
 	struct input_dev *kbd;
 	struct input_dev *ptr;
+	struct input_dev *mtouch;
 	struct xenkbd_page *page;
 	int gref;
 	int irq;
 	struct xenbus_device *xbdev;
 	char phys[32];
+	/* current MT slot/contact ID we are injecting events in */
+	int mtouch_cur_contact_id;
 };
 
 enum { KPARAM_X, KPARAM_Y, KPARAM_CNT };
@@ -100,6 +104,60 @@ static irqreturn_t input_handler(int rq, void *dev_id)
 				input_report_rel(dev, REL_WHEEL,
 						 -event->pos.rel_z);
 			break;
+		case XENKBD_TYPE_MTOUCH:
+			dev = info->mtouch;
+			if (unlikely(!dev))
+				break;
+			if (event->mtouch.contact_id !=
+					info->mtouch_cur_contact_id) {
+				info->mtouch_cur_contact_id =
+					event->mtouch.contact_id;
+				input_mt_slot(dev, event->mtouch.contact_id);
+			}
+			switch (event->mtouch.event_type) {
+			case XENKBD_MT_EV_DOWN:
+				input_mt_report_slot_state(dev, MT_TOOL_FINGER,
+							   true);
+				input_event(dev, EV_ABS, ABS_MT_POSITION_X,
+					    event->mtouch.u.pos.abs_x);
+				input_event(dev, EV_ABS, ABS_MT_POSITION_Y,
+					    event->mtouch.u.pos.abs_y);
+				input_event(dev, EV_ABS, ABS_X,
+					    event->mtouch.u.pos.abs_x);
+				input_event(dev, EV_ABS, ABS_Y,
+					    event->mtouch.u.pos.abs_y);
+				break;
+			case XENKBD_MT_EV_UP:
+				input_mt_report_slot_state(dev, MT_TOOL_FINGER,
+							   false);
+				break;
+			case XENKBD_MT_EV_MOTION:
+				input_event(dev, EV_ABS, ABS_MT_POSITION_X,
+					    event->mtouch.u.pos.abs_x);
+				input_event(dev, EV_ABS, ABS_MT_POSITION_Y,
+					    event->mtouch.u.pos.abs_y);
+				input_event(dev, EV_ABS, ABS_X,
+					    event->mtouch.u.pos.abs_x);
+				input_event(dev, EV_ABS, ABS_Y,
+					    event->mtouch.u.pos.abs_y);
+				break;
+			case XENKBD_MT_EV_SYN:
+				input_mt_sync_frame(dev);
+				break;
+			case XENKBD_MT_EV_SHAPE:
+				input_event(dev, EV_ABS, ABS_MT_TOUCH_MAJOR,
+					    event->mtouch.u.shape.major);
+				input_event(dev, EV_ABS, ABS_MT_TOUCH_MINOR,
+					    event->mtouch.u.shape.minor);
+				break;
+			case XENKBD_MT_EV_ORIENT:
+				input_event(dev, EV_ABS, ABS_MT_ORIENTATION,
+					    event->mtouch.u.orientation);
+				break;
+			}
+			/* only report syn when requested */
+			if (event->mtouch.event_type != XENKBD_MT_EV_SYN)
+				dev = NULL;
 		}
 		if (dev)
 			input_sync(dev);
@@ -115,9 +173,9 @@ static int xenkbd_probe(struct xenbus_device *dev,
 				  const struct xenbus_device_id *id)
 {
 	int ret, i;
-	unsigned int abs;
+	unsigned int abs, touch;
 	struct xenkbd_info *info;
-	struct input_dev *kbd, *ptr;
+	struct input_dev *kbd, *ptr, *mtouch;
 
 	info = kzalloc(sizeof(*info), GFP_KERNEL);
 	if (!info) {
@@ -152,6 +210,17 @@ static int xenkbd_probe(struct xenbus_device *dev,
 		}
 	}
 
+	touch = xenbus_read_unsigned(dev->nodename,
+				     XENKBD_FIELD_FEAT_MTOUCH, 0);
+	if (touch) {
+		ret = xenbus_write(XBT_NIL, dev->nodename,
+				   XENKBD_FIELD_REQ_MTOUCH, "1");
+		if (ret) {
+			pr_warning("xenkbd: can't request multi-touch");
+			touch = 0;
+		}
+	}
+
 	/* keyboard */
 	kbd = input_allocate_device();
 	if (!kbd)
@@ -208,6 +277,66 @@ static int xenkbd_probe(struct xenbus_device *dev,
 	}
 	info->ptr = ptr;
 
+	/* multi-touch device */
+	if (touch) {
+		int num_cont, width, height;
+
+		mtouch = input_allocate_device();
+		if (!mtouch)
+			goto error_nomem;
+
+		num_cont = xenbus_read_unsigned(info->xbdev->nodename,
+						XENKBD_FIELD_MT_NUM_CONTACTS,
+						1);
+		width = xenbus_read_unsigned(info->xbdev->nodename,
+					     XENKBD_FIELD_MT_WIDTH,
+					     XENFB_WIDTH);
+		height = xenbus_read_unsigned(info->xbdev->nodename,
+					      XENKBD_FIELD_MT_HEIGHT,
+					      XENFB_HEIGHT);
+
+		mtouch->name = "Xen Virtual Multi-touch";
+		mtouch->phys = info->phys;
+		mtouch->id.bustype = BUS_PCI;
+		mtouch->id.vendor = 0x5853;
+		mtouch->id.product = 0xfffd;
+
+		input_set_capability(mtouch, EV_KEY, BTN_TOUCH);
+		input_set_abs_params(mtouch, ABS_X,
+				     0, width, 0, 0);
+		input_set_abs_params(mtouch, ABS_Y,
+				     0, height, 0, 0);
+		input_set_abs_params(mtouch, ABS_PRESSURE,
+				     0, 255, 0, 0);
+
+		input_set_abs_params(mtouch, ABS_MT_TOUCH_MAJOR,
+				     0, 255, 0, 0);
+		input_set_abs_params(mtouch, ABS_MT_POSITION_X,
+				     0, width, 0, 0);
+		input_set_abs_params(mtouch, ABS_MT_POSITION_Y,
+				     0, height, 0, 0);
+		input_set_abs_params(mtouch, ABS_MT_PRESSURE,
+				     0, 255, 0, 0);
+
+		ret = input_mt_init_slots(mtouch, num_cont, INPUT_MT_DIRECT);
+		if (ret) {
+			input_free_device(mtouch);
+			xenbus_dev_fatal(info->xbdev, ret,
+					 "input_mt_init_slots");
+			goto error;
+		}
+
+		ret = input_register_device(mtouch);
+		if (ret) {
+			input_free_device(mtouch);
+			xenbus_dev_fatal(info->xbdev, ret,
+					 "input_register_device(mtouch)");
+			goto error;
+		}
+		info->mtouch_cur_contact_id = -1;
+		info->mtouch = mtouch;
+	}
+
 	ret = xenkbd_connect_backend(dev, info);
 	if (ret < 0)
 		goto error;
@@ -240,6 +369,8 @@ static int xenkbd_remove(struct xenbus_device *dev)
 		input_unregister_device(info->kbd);
 	if (info->ptr)
 		input_unregister_device(info->ptr);
+	if (info->mtouch)
+		input_unregister_device(info->mtouch);
 	free_page((unsigned long)info->page);
 	kfree(info);
 	return 0;
-- 
2.7.4