Merge tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted

Pull tracing fixes from Steven Rostedt:

 - Fix error output of boot instance creation failure

   Currently if a boot instance creation fails, instead of printing out
   the name of the instance that failed, it prints "(null)". That is
   because it prints "cur_str" that had already been processed by
   strsep(). Print the saved name instead.

   While at it, print the error code of the failure.

 - Fix use-after-free for same named historgrams

   Histograms can be named so that they can be used in multiple events.
   But if the named histogram has a variable attached, the second event
   that uses the named histogram which duplicates it and needs to free
   the original after duplication leaves the old variable in place and
   still visible. If another histogram uses than variable, it will use
   the stale one which will try to reference the freed duplicate
   histogram and crash the kernel.

   Free the duplicate variables along with the duplicated histogram
   data.

 - Check return value of kthread_run() in event self test

   The events self tests uses a kthread for testing but does not check
   if it succeeded in creating a kthread. If the kthread creation were
   to fail, the code will still try to call kthread_stop() on the error
   returned.

 - Fix race between reading trace_pipe and updating subbuffer size

   If a user is reading the trace_pipe file at the same time they update
   the ring buffer sub-buffer size, can cause the trace_pipe read to
   read stale data. Add trace_access_lock() around updating the ring
   buffer sub-buffer size.

 - Fix eventfs_inode on failure path in creation of the events directory

   In the creation of the "events" directory, if after allocating the
   eventfs_inode a failure is detected, it calls cleanup_ei() which
   calls free_ei(). The free_ei() will test if eventfs_inode being freed
   has no children. It is a bug if it does. But on the failure case of
   the creation of the "events" directory, the children lists have not
   yet been initialized and the free will trigger a warning because
   list_empty() on an uninitialized list returns false.

   Move the initialization into init_ei() where it makes more sense and
   makes sure that a created eventfs_inode has its lists initialized
   upon creation.

 - Check return value of kthread_run() in ftrace direct sample code

   The sample code that shows how to use the ftrace direct calls does
   not test the return of kthread_run() to see if it succeeds. Return a
   failure if the kthread_run() doesn't succeed.

 - Clear user events state on fork in case of alloc failure

   On fork, the child gets a pointer to the parent's user events state.
   It makes a copy of it then updates the child's pointer to it. But if
   the allocation fails, the duplication function leaves the child with
   a pointer to its parent's descriptor. When the child cleans up its
   data, it will free the parent's descriptor while the parent is still
   using it.

   In the duplication function, set the child's user_event_mm to NULL
   before testing if the allocation succeeded, and when it exits it will
   not free the parent's descriptor.

 - Fix retry exhaustion in simple ring buffer reader swap

   simple_ring_buffer_swap_reader_page() starts with retry set to 8 and
   post-decrements it only after a failed link replacement. On the final
   attempt, a successful replacement leaves retry at zero, while a
   failed replacement leaves it at -1.

   But the check for success expects the retry value to be non-zero and
   exits with an error on zero. This is the opposite result. Fix it.

 - Fail nicely when the remote swap_reader_page() returns an error

   Currently, if the swap_reader_page() of a remote buffer fails, it
   triggers a WARN_ON_ONCE() and continues normally. Instead, have it
   exit with an error and a pr_warn() print instead of a full WARNING.

* tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  ring-buffer: Stop remote reader update when page swap fails
  tracing: Fix retry exhaustion in simple ring buffer reader swap
  tracing/user_events: Clear copied tracing state before fork duplication
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-multi-modify
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-modify
  eventfs: Initialize ei->children and ei->list in init_ei()
  tracing: Fix use-after-free in trace_pipe read on sub-buffer order change
  tracing: Fix crash passing ERR_PTR to kthread_stop()
  tracing: Fix use-after-free with same-name named triggers
  tracing: Fix logged instance name on creation failure

1 files changed, 1033 insertions, 0 deletions

diff --git a/drivers/hid/hid-ntrig.c b/drivers/hid/hid-ntrig.c
new file mode 100644
index 000000000..2b31756b5
--- /dev/null
+++ b/drivers/hid/hid-ntrig.c
@@ -0,0 +1,1033 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *  HID driver for N-Trig touchscreens
+ *
+ *  Copyright (c) 2008-2010 Rafi Rubin
+ *  Copyright (c) 2009-2010 Stephane Chatty
+ */
+
+/*
+ */
+
+#include <linux/device.h>
+#include <linux/hid.h>
+#include <linux/usb.h>
+#include "usbhid/usbhid.h"
+#include <linux/module.h>
+#include <linux/slab.h>
+
+#include "hid-ids.h"
+
+#define NTRIG_DUPLICATE_USAGES	0x001
+
+static unsigned int min_width;
+module_param(min_width, uint, 0644);
+MODULE_PARM_DESC(min_width, "Minimum touch contact width to accept.");
+
+static unsigned int min_height;
+module_param(min_height, uint, 0644);
+MODULE_PARM_DESC(min_height, "Minimum touch contact height to accept.");
+
+static unsigned int activate_slack = 1;
+module_param(activate_slack, uint, 0644);
+MODULE_PARM_DESC(activate_slack, "Number of touch frames to ignore at "
+		 "the start of touch input.");
+
+static unsigned int deactivate_slack = 4;
+module_param(deactivate_slack, uint, 0644);
+MODULE_PARM_DESC(deactivate_slack, "Number of empty frames to ignore before "
+		 "deactivating touch.");
+
+static unsigned int activation_width = 64;
+module_param(activation_width, uint, 0644);
+MODULE_PARM_DESC(activation_width, "Width threshold to immediately start "
+		 "processing touch events.");
+
+static unsigned int activation_height = 32;
+module_param(activation_height, uint, 0644);
+MODULE_PARM_DESC(activation_height, "Height threshold to immediately start "
+		 "processing touch events.");
+
+struct ntrig_data {
+	/* Incoming raw values for a single contact */
+	__u16 x, y, w, h;
+	__u16 id;
+
+	bool tipswitch;
+	bool confidence;
+	bool first_contact_touch;
+
+	bool reading_mt;
+
+	__u8 mt_footer[4];
+	__u8 mt_foot_count;
+
+	/* The current activation state. */
+	__s8 act_state;
+
+	/* Empty frames to ignore before recognizing the end of activity */
+	__s8 deactivate_slack;
+
+	/* Frames to ignore before acknowledging the start of activity */
+	__s8 activate_slack;
+
+	/* Minimum size contact to accept */
+	__u16 min_width;
+	__u16 min_height;
+
+	/* Threshold to override activation slack */
+	__u16 activation_width;
+	__u16 activation_height;
+
+	__u16 sensor_logical_width;
+	__u16 sensor_logical_height;
+	__u16 sensor_physical_width;
+	__u16 sensor_physical_height;
+};
+
+
+/*
+ * This function converts the 4 byte raw firmware code into
+ * a string containing 5 comma separated numbers.
+ */
+static int ntrig_version_string(unsigned char *raw, char *buf)
+{
+	__u8 a =  (raw[1] & 0x0e) >> 1;
+	__u8 b =  (raw[0] & 0x3c) >> 2;
+	__u8 c = ((raw[0] & 0x03) << 3) | ((raw[3] & 0xe0) >> 5);
+	__u8 d = ((raw[3] & 0x07) << 3) | ((raw[2] & 0xe0) >> 5);
+	__u8 e =   raw[2] & 0x07;
+
+	/*
+	 * As yet unmapped bits:
+	 * 0b11000000 0b11110001 0b00011000 0b00011000
+	 */
+
+	return sprintf(buf, "%u.%u.%u.%u.%u", a, b, c, d, e);
+}
+
+static inline int ntrig_get_mode(struct hid_device *hdev)
+{
+	struct hid_report *report = hdev->report_enum[HID_FEATURE_REPORT].
+				    report_id_hash[0x0d];
+
+	if (!report || report->maxfield < 1 ||
+	    report->field[0]->report_count < 1)
+		return -EINVAL;
+
+	hid_hw_request(hdev, report, HID_REQ_GET_REPORT);
+	hid_hw_wait(hdev);
+	return (int)report->field[0]->value[0];
+}
+
+static inline void ntrig_set_mode(struct hid_device *hdev, const int mode)
+{
+	struct hid_report *report;
+	__u8 mode_commands[4] = { 0xe, 0xf, 0x1b, 0x10 };
+
+	if (mode < 0 || mode > 3)
+		return;
+
+	report = hdev->report_enum[HID_FEATURE_REPORT].
+		 report_id_hash[mode_commands[mode]];
+
+	if (!report)
+		return;
+
+	hid_hw_request(hdev, report, HID_REQ_GET_REPORT);
+}
+
+static void ntrig_report_version(struct hid_device *hdev)
+{
+	int ret;
+	char buf[20];
+	struct usb_device *usb_dev = hid_to_usb_dev(hdev);
+	unsigned char *data __free(kfree) = kmalloc(8, GFP_KERNEL);
+
+	if (!hid_is_usb(hdev))
+		return;
+
+	if (!data)
+		return;
+
+	ret = usb_control_msg(usb_dev, usb_rcvctrlpipe(usb_dev, 0),
+			      USB_REQ_CLEAR_FEATURE,
+			      USB_TYPE_CLASS | USB_RECIP_INTERFACE |
+			      USB_DIR_IN,
+			      0x30c, 1, data, 8,
+			      USB_CTRL_SET_TIMEOUT);
+
+	if (ret == 8) {
+		ret = ntrig_version_string(&data[2], buf);
+
+		hid_info(hdev, "Firmware version: %s (%02x%02x %02x%02x)\n",
+			 buf, data[2], data[3], data[4], data[5]);
+	}
+}
+
+static ssize_t show_phys_width(struct device *dev,
+			       struct device_attribute *attr,
+			       char *buf)
+{
+	struct hid_device *hdev = to_hid_device(dev);
+	struct ntrig_data *nd = hid_get_drvdata(hdev);
+
+	return sprintf(buf, "%d\n", nd->sensor_physical_width);
+}
+
+static DEVICE_ATTR(sensor_physical_width, S_IRUGO, show_phys_width, NULL);
+
+static ssize_t show_phys_height(struct device *dev,
+				struct device_attribute *attr,
+				char *buf)
+{
+	struct hid_device *hdev = to_hid_device(dev);
+	struct ntrig_data *nd = hid_get_drvdata(hdev);
+
+	return sprintf(buf, "%d\n", nd->sensor_physical_height);
+}
+
+static DEVICE_ATTR(sensor_physical_height, S_IRUGO, show_phys_height, NULL);
+
+static ssize_t show_log_width(struct device *dev,
+			      struct device_attribute *attr,
+			      char *buf)
+{
+	struct hid_device *hdev = to_hid_device(dev);
+	struct ntrig_data *nd = hid_get_drvdata(hdev);
+
+	return sprintf(buf, "%d\n", nd->sensor_logical_width);
+}
+
+static DEVICE_ATTR(sensor_logical_width, S_IRUGO, show_log_width, NULL);
+
+static ssize_t show_log_height(struct device *dev,
+			       struct device_attribute *attr,
+			       char *buf)
+{
+	struct hid_device *hdev = to_hid_device(dev);
+	struct ntrig_data *nd = hid_get_drvdata(hdev);
+
+	return sprintf(buf, "%d\n", nd->sensor_logical_height);
+}
+
+static DEVICE_ATTR(sensor_logical_height, S_IRUGO, show_log_height, NULL);
+
+static ssize_t show_min_width(struct device *dev,
+			      struct device_attribute *attr,
+			      char *buf)
+{
+	struct hid_device *hdev = to_hid_device(dev);
+	struct ntrig_data *nd = hid_get_drvdata(hdev);
+
+	return sprintf(buf, "%d\n", nd->min_width *
+				    nd->sensor_physical_width /
+				    nd->sensor_logical_width);
+}
+
+static ssize_t set_min_width(struct device *dev,
+			     struct device_attribute *attr,
+			     const char *buf, size_t count)
+{
+	struct hid_device *hdev = to_hid_device(dev);
+	struct ntrig_data *nd = hid_get_drvdata(hdev);
+
+	unsigned long val;
+
+	if (kstrtoul(buf, 0, &val))
+		return -EINVAL;
+
+	if (val > nd->sensor_physical_width)
+		return -EINVAL;
+
+	nd->min_width = val * nd->sensor_logical_width /
+			      nd->sensor_physical_width;
+
+	return count;
+}
+
+static DEVICE_ATTR(min_width, S_IWUSR | S_IRUGO, show_min_width, set_min_width);
+
+static ssize_t show_min_height(struct device *dev,
+			       struct device_attribute *attr,
+			       char *buf)
+{
+	struct hid_device *hdev = to_hid_device(dev);
+	struct ntrig_data *nd = hid_get_drvdata(hdev);
+
+	return sprintf(buf, "%d\n", nd->min_height *
+				    nd->sensor_physical_height /
+				    nd->sensor_logical_height);
+}
+
+static ssize_t set_min_height(struct device *dev,
+			      struct device_attribute *attr,
+			      const char *buf, size_t count)
+{
+	struct hid_device *hdev = to_hid_device(dev);
+	struct ntrig_data *nd = hid_get_drvdata(hdev);
+
+	unsigned long val;
+
+	if (kstrtoul(buf, 0, &val))
+		return -EINVAL;
+
+	if (val > nd->sensor_physical_height)
+		return -EINVAL;
+
+	nd->min_height = val * nd->sensor_logical_height /
+			       nd->sensor_physical_height;
+
+	return count;
+}
+
+static DEVICE_ATTR(min_height, S_IWUSR | S_IRUGO, show_min_height,
+		   set_min_height);
+
+static ssize_t show_activate_slack(struct device *dev,
+				   struct device_attribute *attr,
+				   char *buf)
+{
+	struct hid_device *hdev = to_hid_device(dev);
+	struct ntrig_data *nd = hid_get_drvdata(hdev);
+
+	return sprintf(buf, "%d\n", nd->activate_slack);
+}
+
+static ssize_t set_activate_slack(struct device *dev,
+				  struct device_attribute *attr,
+				  const char *buf, size_t count)
+{
+	struct hid_device *hdev = to_hid_device(dev);
+	struct ntrig_data *nd = hid_get_drvdata(hdev);
+
+	unsigned long val;
+
+	if (kstrtoul(buf, 0, &val))
+		return -EINVAL;
+
+	if (val > 0x7f)
+		return -EINVAL;
+
+	nd->activate_slack = val;
+
+	return count;
+}
+
+static DEVICE_ATTR(activate_slack, S_IWUSR | S_IRUGO, show_activate_slack,
+		   set_activate_slack);
+
+static ssize_t show_activation_width(struct device *dev,
+				     struct device_attribute *attr,
+				     char *buf)
+{
+	struct hid_device *hdev = to_hid_device(dev);
+	struct ntrig_data *nd = hid_get_drvdata(hdev);
+
+	return sprintf(buf, "%d\n", nd->activation_width *
+				    nd->sensor_physical_width /
+				    nd->sensor_logical_width);
+}
+
+static ssize_t set_activation_width(struct device *dev,
+				    struct device_attribute *attr,
+				    const char *buf, size_t count)
+{
+	struct hid_device *hdev = to_hid_device(dev);
+	struct ntrig_data *nd = hid_get_drvdata(hdev);
+
+	unsigned long val;
+
+	if (kstrtoul(buf, 0, &val))
+		return -EINVAL;
+
+	if (val > nd->sensor_physical_width)
+		return -EINVAL;
+
+	nd->activation_width = val * nd->sensor_logical_width /
+				     nd->sensor_physical_width;
+
+	return count;
+}
+
+static DEVICE_ATTR(activation_width, S_IWUSR | S_IRUGO, show_activation_width,
+		   set_activation_width);
+
+static ssize_t show_activation_height(struct device *dev,
+				      struct device_attribute *attr,
+				      char *buf)
+{
+	struct hid_device *hdev = to_hid_device(dev);
+	struct ntrig_data *nd = hid_get_drvdata(hdev);
+
+	return sprintf(buf, "%d\n", nd->activation_height *
+				    nd->sensor_physical_height /
+				    nd->sensor_logical_height);
+}
+
+static ssize_t set_activation_height(struct device *dev,
+				     struct device_attribute *attr,
+				     const char *buf, size_t count)
+{
+	struct hid_device *hdev = to_hid_device(dev);
+	struct ntrig_data *nd = hid_get_drvdata(hdev);
+
+	unsigned long val;
+
+	if (kstrtoul(buf, 0, &val))
+		return -EINVAL;
+
+	if (val > nd->sensor_physical_height)
+		return -EINVAL;
+
+	nd->activation_height = val * nd->sensor_logical_height /
+				      nd->sensor_physical_height;
+
+	return count;
+}
+
+static DEVICE_ATTR(activation_height, S_IWUSR | S_IRUGO,
+		   show_activation_height, set_activation_height);
+
+static ssize_t show_deactivate_slack(struct device *dev,
+				     struct device_attribute *attr,
+				     char *buf)
+{
+	struct hid_device *hdev = to_hid_device(dev);
+	struct ntrig_data *nd = hid_get_drvdata(hdev);
+
+	return sprintf(buf, "%d\n", -nd->deactivate_slack);
+}
+
+static ssize_t set_deactivate_slack(struct device *dev,
+				    struct device_attribute *attr,
+				    const char *buf, size_t count)
+{
+	struct hid_device *hdev = to_hid_device(dev);
+	struct ntrig_data *nd = hid_get_drvdata(hdev);
+
+	unsigned long val;
+
+	if (kstrtoul(buf, 0, &val))
+		return -EINVAL;
+
+	/*
+	 * No more than 8 terminal frames have been observed so far
+	 * and higher slack is highly likely to leave the single
+	 * touch emulation stuck down.
+	 */
+	if (val > 7)
+		return -EINVAL;
+
+	nd->deactivate_slack = -val;
+
+	return count;
+}
+
+static DEVICE_ATTR(deactivate_slack, S_IWUSR | S_IRUGO, show_deactivate_slack,
+		   set_deactivate_slack);
+
+static struct attribute *sysfs_attrs[] = {
+	&dev_attr_sensor_physical_width.attr,
+	&dev_attr_sensor_physical_height.attr,
+	&dev_attr_sensor_logical_width.attr,
+	&dev_attr_sensor_logical_height.attr,
+	&dev_attr_min_height.attr,
+	&dev_attr_min_width.attr,
+	&dev_attr_activate_slack.attr,
+	&dev_attr_activation_width.attr,
+	&dev_attr_activation_height.attr,
+	&dev_attr_deactivate_slack.attr,
+	NULL
+};
+
+static const struct attribute_group ntrig_attribute_group = {
+	.attrs = sysfs_attrs
+};
+
+/*
+ * this driver is aimed at two firmware versions in circulation:
+ *  - dual pen/finger single touch
+ *  - finger multitouch, pen not working
+ */
+
+static int ntrig_input_mapping(struct hid_device *hdev, struct hid_input *hi,
+			       struct hid_field *field, struct hid_usage *usage,
+			       unsigned long **bit, int *max)
+{
+	struct ntrig_data *nd = hid_get_drvdata(hdev);
+
+	/* No special mappings needed for the pen and single touch */
+	if (field->physical)
+		return 0;
+
+	switch (usage->hid & HID_USAGE_PAGE) {
+	case HID_UP_GENDESK:
+		switch (usage->hid) {
+		case HID_GD_X:
+			hid_map_usage(hi, usage, bit, max,
+					EV_ABS, ABS_MT_POSITION_X);
+			input_set_abs_params(hi->input, ABS_X,
+					field->logical_minimum,
+					field->logical_maximum, 0, 0);
+
+			if (!nd->sensor_logical_width) {
+				nd->sensor_logical_width =
+					field->logical_maximum -
+					field->logical_minimum;
+				nd->sensor_physical_width =
+					field->physical_maximum -
+					field->physical_minimum;
+				nd->activation_width = activation_width *
+					nd->sensor_logical_width /
+					nd->sensor_physical_width;
+				nd->min_width = min_width *
+					nd->sensor_logical_width /
+					nd->sensor_physical_width;
+			}
+			return 1;
+		case HID_GD_Y:
+			hid_map_usage(hi, usage, bit, max,
+					EV_ABS, ABS_MT_POSITION_Y);
+			input_set_abs_params(hi->input, ABS_Y,
+					field->logical_minimum,
+					field->logical_maximum, 0, 0);
+
+			if (!nd->sensor_logical_height) {
+				nd->sensor_logical_height =
+					field->logical_maximum -
+					field->logical_minimum;
+				nd->sensor_physical_height =
+					field->physical_maximum -
+					field->physical_minimum;
+				nd->activation_height = activation_height *
+					nd->sensor_logical_height /
+					nd->sensor_physical_height;
+				nd->min_height = min_height *
+					nd->sensor_logical_height /
+					nd->sensor_physical_height;
+			}
+			return 1;
+		}
+		return 0;
+
+	case HID_UP_DIGITIZER:
+		switch (usage->hid) {
+		/* we do not want to map these for now */
+		case HID_DG_CONTACTID: /* Not trustworthy, squelch for now */
+		case HID_DG_INPUTMODE:
+		case HID_DG_DEVICEINDEX:
+		case HID_DG_CONTACTMAX:
+			return -1;
+
+		/* width/height mapped on TouchMajor/TouchMinor/Orientation */
+		case HID_DG_WIDTH:
+			hid_map_usage(hi, usage, bit, max,
+				      EV_ABS, ABS_MT_TOUCH_MAJOR);
+			return 1;
+		case HID_DG_HEIGHT:
+			hid_map_usage(hi, usage, bit, max,
+				      EV_ABS, ABS_MT_TOUCH_MINOR);
+			input_set_abs_params(hi->input, ABS_MT_ORIENTATION,
+					     0, 1, 0, 0);
+			return 1;
+		}
+		return 0;
+
+	case 0xff000000:
+		/* we do not want to map these: no input-oriented meaning */
+		return -1;
+	}
+
+	return 0;
+}
+
+static int ntrig_input_mapped(struct hid_device *hdev, struct hid_input *hi,
+			      struct hid_field *field, struct hid_usage *usage,
+			      unsigned long **bit, int *max)
+{
+	/* No special mappings needed for the pen and single touch */
+	if (field->physical)
+		return 0;
+
+	if (usage->type == EV_KEY || usage->type == EV_REL
+			|| usage->type == EV_ABS)
+		clear_bit(usage->code, *bit);
+
+	return 0;
+}
+
+/*
+ * this function is called upon all reports
+ * so that we can filter contact point information,
+ * decide whether we are in multi or single touch mode
+ * and call input_mt_sync after each point if necessary
+ */
+static int ntrig_event (struct hid_device *hid, struct hid_field *field,
+			struct hid_usage *usage, __s32 value)
+{
+	struct ntrig_data *nd = hid_get_drvdata(hid);
+	struct input_dev *input;
+
+	/* Skip processing if not a claimed input */
+	if (!(hid->claimed & HID_CLAIMED_INPUT))
+		goto not_claimed_input;
+
+	/* This function is being called before the structures are fully
+	 * initialized */
+	if(!(field->hidinput && field->hidinput->input))
+		return -EINVAL;
+
+	input = field->hidinput->input;
+
+	/* No special handling needed for the pen */
+	if (field->application == HID_DG_PEN)
+		return 0;
+
+	switch (usage->hid) {
+	case 0xff000001:
+		/* Tag indicating the start of a multitouch group */
+		nd->reading_mt = true;
+		nd->first_contact_touch = false;
+		break;
+	case HID_DG_TIPSWITCH:
+		nd->tipswitch = value;
+		/* Prevent emission of touch until validated */
+		return 1;
+	case HID_DG_CONFIDENCE:
+		nd->confidence = value;
+		break;
+	case HID_GD_X:
+		nd->x = value;
+		/* Clear the contact footer */
+		nd->mt_foot_count = 0;
+		break;
+	case HID_GD_Y:
+		nd->y = value;
+		break;
+	case HID_DG_CONTACTID:
+		nd->id = value;
+		break;
+	case HID_DG_WIDTH:
+		nd->w = value;
+		break;
+	case HID_DG_HEIGHT:
+		nd->h = value;
+		/*
+		 * when in single touch mode, this is the last
+		 * report received in a finger event. We want
+		 * to emit a normal (X, Y) position
+		 */
+		if (!nd->reading_mt) {
+			/*
+			 * TipSwitch indicates the presence of a
+			 * finger in single touch mode.
+			 */
+			input_report_key(input, BTN_TOUCH,
+					 nd->tipswitch);
+			input_report_key(input, BTN_TOOL_DOUBLETAP,
+					 nd->tipswitch);
+			input_event(input, EV_ABS, ABS_X, nd->x);
+			input_event(input, EV_ABS, ABS_Y, nd->y);
+		}
+		break;
+	case 0xff000002:
+		/*
+		 * we receive this when the device is in multitouch
+		 * mode. The first of the three values tagged with
+		 * this usage tells if the contact point is real
+		 * or a placeholder
+		 */
+
+		/* Shouldn't get more than 4 footer packets, so skip */
+		if (nd->mt_foot_count >= 4)
+			break;
+
+		nd->mt_footer[nd->mt_foot_count++] = value;
+
+		/* if the footer isn't complete break */
+		if (nd->mt_foot_count != 4)
+			break;
+
+		/* Pen activity signal. */
+		if (nd->mt_footer[2]) {
+			/*
+			 * When the pen deactivates touch, we see a
+			 * bogus frame with ContactCount > 0.
+			 * We can
+			 * save a bit of work by ensuring act_state < 0
+			 * even if deactivation slack is turned off.
+			 */
+			nd->act_state = deactivate_slack - 1;
+			nd->confidence = false;
+			break;
+		}
+
+		/*
+		 * The first footer value indicates the presence of a
+		 * finger.
+		 */
+		if (nd->mt_footer[0]) {
+			/*
+			 * We do not want to process contacts under
+			 * the size threshold, but do not want to
+			 * ignore them for activation state
+			 */
+			if (nd->w < nd->min_width ||
+			    nd->h < nd->min_height)
+				nd->confidence = false;
+		} else
+			break;
+
+		if (nd->act_state > 0) {
+			/*
+			 * Contact meets the activation size threshold
+			 */
+			if (nd->w >= nd->activation_width &&
+			    nd->h >= nd->activation_height) {
+				if (nd->id)
+					/*
+					 * first contact, activate now
+					 */
+					nd->act_state = 0;
+				else {
+					/*
+					 * avoid corrupting this frame
+					 * but ensure next frame will
+					 * be active
+					 */
+					nd->act_state = 1;
+					break;
+				}
+			} else
+				/*
+				 * Defer adjusting the activation state
+				 * until the end of the frame.
+				 */
+				break;
+		}
+
+		/* Discarding this contact */
+		if (!nd->confidence)
+			break;
+
+		/* emit a normal (X, Y) for the first point only */
+		if (nd->id == 0) {
+			/*
+			 * TipSwitch is superfluous in multitouch
+			 * mode.  The footer events tell us
+			 * if there is a finger on the screen or
+			 * not.
+			 */
+			nd->first_contact_touch = nd->confidence;
+			input_event(input, EV_ABS, ABS_X, nd->x);
+			input_event(input, EV_ABS, ABS_Y, nd->y);
+		}
+
+		/* Emit MT events */
+		input_event(input, EV_ABS, ABS_MT_POSITION_X, nd->x);
+		input_event(input, EV_ABS, ABS_MT_POSITION_Y, nd->y);
+
+		/*
+		 * Translate from height and width to size
+		 * and orientation.
+		 */
+		if (nd->w > nd->h) {
+			input_event(input, EV_ABS,
+					ABS_MT_ORIENTATION, 1);
+			input_event(input, EV_ABS,
+					ABS_MT_TOUCH_MAJOR, nd->w);
+			input_event(input, EV_ABS,
+					ABS_MT_TOUCH_MINOR, nd->h);
+		} else {
+			input_event(input, EV_ABS,
+					ABS_MT_ORIENTATION, 0);
+			input_event(input, EV_ABS,
+					ABS_MT_TOUCH_MAJOR, nd->h);
+			input_event(input, EV_ABS,
+					ABS_MT_TOUCH_MINOR, nd->w);
+		}
+		input_mt_sync(field->hidinput->input);
+		break;
+
+	case HID_DG_CONTACTCOUNT: /* End of a multitouch group */
+		if (!nd->reading_mt) /* Just to be sure */
+			break;
+
+		nd->reading_mt = false;
+
+
+		/*
+		 * Activation state machine logic:
+		 *
+		 * Fundamental states:
+		 *	state >  0: Inactive
+		 *	state <= 0: Active
+		 *	state <  -deactivate_slack:
+		 *		 Pen termination of touch
+		 *
+		 * Specific values of interest
+		 *	state == activate_slack
+		 *		 no valid input since the last reset
+		 *
+		 *	state == 0
+		 *		 general operational state
+		 *
+		 *	state == -deactivate_slack
+		 *		 read sufficient empty frames to accept
+		 *		 the end of input and reset
+		 */
+
+		if (nd->act_state > 0) { /* Currently inactive */
+			if (value)
+				/*
+				 * Consider each live contact as
+				 * evidence of intentional activity.
+				 */
+				nd->act_state = (nd->act_state > value)
+						? nd->act_state - value
+						: 0;
+			else
+				/*
+				 * Empty frame before we hit the
+				 * activity threshold, reset.
+				 */
+				nd->act_state = nd->activate_slack;
+
+			/*
+			 * Entered this block inactive and no
+			 * coordinates sent this frame, so hold off
+			 * on button state.
+			 */
+			break;
+		} else { /* Currently active */
+			if (value && nd->act_state >=
+				     nd->deactivate_slack)
+				/*
+				 * Live point: clear accumulated
+				 * deactivation count.
+				 */
+				nd->act_state = 0;
+			else if (nd->act_state <= nd->deactivate_slack)
+				/*
+				 * We've consumed the deactivation
+				 * slack, time to deactivate and reset.
+				 */
+				nd->act_state =
+					nd->activate_slack;
+			else { /* Move towards deactivation */
+				nd->act_state--;
+				break;
+			}
+		}
+
+		if (nd->first_contact_touch && nd->act_state <= 0) {
+			/*
+			 * Check to see if we're ready to start
+			 * emitting touch events.
+			 *
+			 * Note: activation slack will decrease over
+			 * the course of the frame, and it will be
+			 * inconsistent from the start to the end of
+			 * the frame.  However if the frame starts
+			 * with slack, first_contact_touch will still
+			 * be 0 and we will not get to this point.
+			 */
+			input_report_key(input, BTN_TOOL_DOUBLETAP, 1);
+			input_report_key(input, BTN_TOUCH, 1);
+		} else {
+			input_report_key(input, BTN_TOOL_DOUBLETAP, 0);
+			input_report_key(input, BTN_TOUCH, 0);
+		}
+		break;
+
+	default:
+		/* fall-back to the generic hidinput handling */
+		return 0;
+	}
+
+not_claimed_input:
+
+	/* we have handled the hidinput part, now remains hiddev */
+	if ((hid->claimed & HID_CLAIMED_HIDDEV) && hid->hiddev_hid_event)
+		hid->hiddev_hid_event(hid, field, usage, value);
+
+	return 1;
+}
+
+static int ntrig_input_configured(struct hid_device *hid,
+		struct hid_input *hidinput)
+
+{
+	struct input_dev *input = hidinput->input;
+
+	if (hidinput->report->maxfield < 1)
+		return 0;
+
+	switch (hidinput->report->field[0]->application) {
+	case HID_DG_PEN:
+		input->name = "N-Trig Pen";
+		break;
+	case HID_DG_TOUCHSCREEN:
+		/* These keys are redundant for fingers, clear them
+		 * to prevent incorrect identification */
+		__clear_bit(BTN_TOOL_PEN, input->keybit);
+		__clear_bit(BTN_TOOL_FINGER, input->keybit);
+		__clear_bit(BTN_0, input->keybit);
+		__set_bit(BTN_TOOL_DOUBLETAP, input->keybit);
+		/*
+		 * The physical touchscreen (single touch)
+		 * input has a value for physical, whereas
+		 * the multitouch only has logical input
+		 * fields.
+		 */
+		input->name = (hidinput->report->field[0]->physical) ?
+							"N-Trig Touchscreen" :
+							"N-Trig MultiTouch";
+		break;
+	}
+
+	return 0;
+}
+
+static int ntrig_probe(struct hid_device *hdev, const struct hid_device_id *id)
+{
+	int ret;
+	struct ntrig_data *nd;
+	struct hid_report *report;
+
+	if (id->driver_data)
+		hdev->quirks |= HID_QUIRK_MULTI_INPUT
+				| HID_QUIRK_NO_INIT_REPORTS;
+
+	nd = kmalloc_obj(struct ntrig_data);
+	if (!nd) {
+		hid_err(hdev, "cannot allocate N-Trig data\n");
+		return -ENOMEM;
+	}
+
+	nd->reading_mt = false;
+	nd->min_width = 0;
+	nd->min_height = 0;
+	nd->activate_slack = activate_slack;
+	nd->act_state = activate_slack;
+	nd->deactivate_slack = -deactivate_slack;
+	nd->sensor_logical_width = 1;
+	nd->sensor_logical_height = 1;
+	nd->sensor_physical_width = 1;
+	nd->sensor_physical_height = 1;
+
+	hid_set_drvdata(hdev, nd);
+
+	ret = hid_parse(hdev);
+	if (ret) {
+		hid_err(hdev, "parse failed\n");
+		goto err_free;
+	}
+
+	ret = hid_hw_start(hdev, HID_CONNECT_DEFAULT & ~HID_CONNECT_FF);
+	if (ret) {
+		hid_err(hdev, "hw start failed\n");
+		goto err_free;
+	}
+
+	/* This is needed for devices with more recent firmware versions */
+	report = hdev->report_enum[HID_FEATURE_REPORT].report_id_hash[0x0a];
+	if (report) {
+		/* Let the device settle to ensure the wakeup message gets
+		 * through */
+		hid_hw_wait(hdev);
+		hid_hw_request(hdev, report, HID_REQ_GET_REPORT);
+
+		/*
+		 * Sanity check: if the current mode is invalid reset it to
+		 * something reasonable.
+		 */
+		if (ntrig_get_mode(hdev) >= 4)
+			ntrig_set_mode(hdev, 3);
+	}
+
+	ntrig_report_version(hdev);
+
+	ret = sysfs_create_group(&hdev->dev.kobj,
+			&ntrig_attribute_group);
+	if (ret)
+		hid_err(hdev, "cannot create sysfs group\n");
+
+	return 0;
+err_free:
+	kfree(nd);
+	return ret;
+}
+
+static void ntrig_remove(struct hid_device *hdev)
+{
+	sysfs_remove_group(&hdev->dev.kobj,
+			   &ntrig_attribute_group);
+	hid_hw_stop(hdev);
+	kfree(hid_get_drvdata(hdev));
+}
+
+static const struct hid_device_id ntrig_devices[] = {
+	{ HID_USB_DEVICE(USB_VENDOR_ID_NTRIG, USB_DEVICE_ID_NTRIG_TOUCH_SCREEN),
+		.driver_data = NTRIG_DUPLICATE_USAGES },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_NTRIG, USB_DEVICE_ID_NTRIG_TOUCH_SCREEN_1),
+		.driver_data = NTRIG_DUPLICATE_USAGES },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_NTRIG, USB_DEVICE_ID_NTRIG_TOUCH_SCREEN_2),
+		.driver_data = NTRIG_DUPLICATE_USAGES },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_NTRIG, USB_DEVICE_ID_NTRIG_TOUCH_SCREEN_3),
+		.driver_data = NTRIG_DUPLICATE_USAGES },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_NTRIG, USB_DEVICE_ID_NTRIG_TOUCH_SCREEN_4),
+		.driver_data = NTRIG_DUPLICATE_USAGES },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_NTRIG, USB_DEVICE_ID_NTRIG_TOUCH_SCREEN_5),
+		.driver_data = NTRIG_DUPLICATE_USAGES },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_NTRIG, USB_DEVICE_ID_NTRIG_TOUCH_SCREEN_6),
+		.driver_data = NTRIG_DUPLICATE_USAGES },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_NTRIG, USB_DEVICE_ID_NTRIG_TOUCH_SCREEN_7),
+		.driver_data = NTRIG_DUPLICATE_USAGES },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_NTRIG, USB_DEVICE_ID_NTRIG_TOUCH_SCREEN_8),
+		.driver_data = NTRIG_DUPLICATE_USAGES },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_NTRIG, USB_DEVICE_ID_NTRIG_TOUCH_SCREEN_9),
+		.driver_data = NTRIG_DUPLICATE_USAGES },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_NTRIG, USB_DEVICE_ID_NTRIG_TOUCH_SCREEN_10),
+		.driver_data = NTRIG_DUPLICATE_USAGES },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_NTRIG, USB_DEVICE_ID_NTRIG_TOUCH_SCREEN_11),
+		.driver_data = NTRIG_DUPLICATE_USAGES },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_NTRIG, USB_DEVICE_ID_NTRIG_TOUCH_SCREEN_12),
+		.driver_data = NTRIG_DUPLICATE_USAGES },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_NTRIG, USB_DEVICE_ID_NTRIG_TOUCH_SCREEN_13),
+		.driver_data = NTRIG_DUPLICATE_USAGES },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_NTRIG, USB_DEVICE_ID_NTRIG_TOUCH_SCREEN_14),
+		.driver_data = NTRIG_DUPLICATE_USAGES },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_NTRIG, USB_DEVICE_ID_NTRIG_TOUCH_SCREEN_15),
+		.driver_data = NTRIG_DUPLICATE_USAGES },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_NTRIG, USB_DEVICE_ID_NTRIG_TOUCH_SCREEN_16),
+		.driver_data = NTRIG_DUPLICATE_USAGES },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_NTRIG, USB_DEVICE_ID_NTRIG_TOUCH_SCREEN_17),
+		.driver_data = NTRIG_DUPLICATE_USAGES },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_NTRIG, USB_DEVICE_ID_NTRIG_TOUCH_SCREEN_18),
+		.driver_data = NTRIG_DUPLICATE_USAGES },
+	{ }
+};
+MODULE_DEVICE_TABLE(hid, ntrig_devices);
+
+static const struct hid_usage_id ntrig_grabbed_usages[] = {
+	{ HID_ANY_ID, HID_ANY_ID, HID_ANY_ID },
+	{ HID_ANY_ID - 1, HID_ANY_ID - 1, HID_ANY_ID - 1 }
+};
+
+static struct hid_driver ntrig_driver = {
+	.name = "ntrig",
+	.id_table = ntrig_devices,
+	.probe = ntrig_probe,
+	.remove = ntrig_remove,
+	.input_mapping = ntrig_input_mapping,
+	.input_mapped = ntrig_input_mapped,
+	.input_configured = ntrig_input_configured,
+	.usage_table = ntrig_grabbed_usages,
+	.event = ntrig_event,
+};
+module_hid_driver(ntrig_driver);
+
+MODULE_DESCRIPTION("HID driver for N-Trig touchscreens");
+MODULE_LICENSE("GPL");