Adding upstream version 5.10.209.upstream/5.10.209upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 2658 insertions, 0 deletions

diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c
new file mode 100644
index 000000000..476967ab6
--- /dev/null
+++ b/drivers/hid/hid-core.c
@@ -0,0 +1,2658 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *  HID support for Linux
+ *
+ *  Copyright (c) 1999 Andreas Gal
+ *  Copyright (c) 2000-2005 Vojtech Pavlik <vojtech@suse.cz>
+ *  Copyright (c) 2005 Michael Haboustak <mike-@cinci.rr.com> for Concept2, Inc
+ *  Copyright (c) 2006-2012 Jiri Kosina
+ */
+
+/*
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/list.h>
+#include <linux/mm.h>
+#include <linux/spinlock.h>
+#include <asm/unaligned.h>
+#include <asm/byteorder.h>
+#include <linux/input.h>
+#include <linux/wait.h>
+#include <linux/vmalloc.h>
+#include <linux/sched.h>
+#include <linux/semaphore.h>
+
+#include <linux/hid.h>
+#include <linux/hiddev.h>
+#include <linux/hid-debug.h>
+#include <linux/hidraw.h>
+
+#include "hid-ids.h"
+
+/*
+ * Version Information
+ */
+
+#define DRIVER_DESC "HID core driver"
+
+int hid_debug = 0;
+module_param_named(debug, hid_debug, int, 0600);
+MODULE_PARM_DESC(debug, "toggle HID debugging messages");
+EXPORT_SYMBOL_GPL(hid_debug);
+
+static int hid_ignore_special_drivers = 0;
+module_param_named(ignore_special_drivers, hid_ignore_special_drivers, int, 0600);
+MODULE_PARM_DESC(ignore_special_drivers, "Ignore any special drivers and handle all devices by generic driver");
+
+/*
+ * Register a new report for a device.
+ */
+
+struct hid_report *hid_register_report(struct hid_device *device,
+				       unsigned int type, unsigned int id,
+				       unsigned int application)
+{
+	struct hid_report_enum *report_enum = device->report_enum + type;
+	struct hid_report *report;
+
+	if (id >= HID_MAX_IDS)
+		return NULL;
+	if (report_enum->report_id_hash[id])
+		return report_enum->report_id_hash[id];
+
+	report = kzalloc(sizeof(struct hid_report), GFP_KERNEL);
+	if (!report)
+		return NULL;
+
+	if (id != 0)
+		report_enum->numbered = 1;
+
+	report->id = id;
+	report->type = type;
+	report->size = 0;
+	report->device = device;
+	report->application = application;
+	report_enum->report_id_hash[id] = report;
+
+	list_add_tail(&report->list, &report_enum->report_list);
+
+	return report;
+}
+EXPORT_SYMBOL_GPL(hid_register_report);
+
+/*
+ * Register a new field for this report.
+ */
+
+static struct hid_field *hid_register_field(struct hid_report *report, unsigned usages)
+{
+	struct hid_field *field;
+
+	if (report->maxfield == HID_MAX_FIELDS) {
+		hid_err(report->device, "too many fields in report\n");
+		return NULL;
+	}
+
+	field = kzalloc((sizeof(struct hid_field) +
+			 usages * sizeof(struct hid_usage) +
+			 usages * sizeof(unsigned)), GFP_KERNEL);
+	if (!field)
+		return NULL;
+
+	field->index = report->maxfield++;
+	report->field[field->index] = field;
+	field->usage = (struct hid_usage *)(field + 1);
+	field->value = (s32 *)(field->usage + usages);
+	field->report = report;
+
+	return field;
+}
+
+/*
+ * Open a collection. The type/usage is pushed on the stack.
+ */
+
+static int open_collection(struct hid_parser *parser, unsigned type)
+{
+	struct hid_collection *collection;
+	unsigned usage;
+	int collection_index;
+
+	usage = parser->local.usage[0];
+
+	if (parser->collection_stack_ptr == parser->collection_stack_size) {
+		unsigned int *collection_stack;
+		unsigned int new_size = parser->collection_stack_size +
+					HID_COLLECTION_STACK_SIZE;
+
+		collection_stack = krealloc(parser->collection_stack,
+					    new_size * sizeof(unsigned int),
+					    GFP_KERNEL);
+		if (!collection_stack)
+			return -ENOMEM;
+
+		parser->collection_stack = collection_stack;
+		parser->collection_stack_size = new_size;
+	}
+
+	if (parser->device->maxcollection == parser->device->collection_size) {
+		collection = kmalloc(
+				array3_size(sizeof(struct hid_collection),
+					    parser->device->collection_size,
+					    2),
+				GFP_KERNEL);
+		if (collection == NULL) {
+			hid_err(parser->device, "failed to reallocate collection array\n");
+			return -ENOMEM;
+		}
+		memcpy(collection, parser->device->collection,
+			sizeof(struct hid_collection) *
+			parser->device->collection_size);
+		memset(collection + parser->device->collection_size, 0,
+			sizeof(struct hid_collection) *
+			parser->device->collection_size);
+		kfree(parser->device->collection);
+		parser->device->collection = collection;
+		parser->device->collection_size *= 2;
+	}
+
+	parser->collection_stack[parser->collection_stack_ptr++] =
+		parser->device->maxcollection;
+
+	collection_index = parser->device->maxcollection++;
+	collection = parser->device->collection + collection_index;
+	collection->type = type;
+	collection->usage = usage;
+	collection->level = parser->collection_stack_ptr - 1;
+	collection->parent_idx = (collection->level == 0) ? -1 :
+		parser->collection_stack[collection->level - 1];
+
+	if (type == HID_COLLECTION_APPLICATION)
+		parser->device->maxapplication++;
+
+	return 0;
+}
+
+/*
+ * Close a collection.
+ */
+
+static int close_collection(struct hid_parser *parser)
+{
+	if (!parser->collection_stack_ptr) {
+		hid_err(parser->device, "collection stack underflow\n");
+		return -EINVAL;
+	}
+	parser->collection_stack_ptr--;
+	return 0;
+}
+
+/*
+ * Climb up the stack, search for the specified collection type
+ * and return the usage.
+ */
+
+static unsigned hid_lookup_collection(struct hid_parser *parser, unsigned type)
+{
+	struct hid_collection *collection = parser->device->collection;
+	int n;
+
+	for (n = parser->collection_stack_ptr - 1; n >= 0; n--) {
+		unsigned index = parser->collection_stack[n];
+		if (collection[index].type == type)
+			return collection[index].usage;
+	}
+	return 0; /* we know nothing about this usage type */
+}
+
+/*
+ * Concatenate usage which defines 16 bits or less with the
+ * currently defined usage page to form a 32 bit usage
+ */
+
+static void complete_usage(struct hid_parser *parser, unsigned int index)
+{
+	parser->local.usage[index] &= 0xFFFF;
+	parser->local.usage[index] |=
+		(parser->global.usage_page & 0xFFFF) << 16;
+}
+
+/*
+ * Add a usage to the temporary parser table.
+ */
+
+static int hid_add_usage(struct hid_parser *parser, unsigned usage, u8 size)
+{
+	if (parser->local.usage_index >= HID_MAX_USAGES) {
+		hid_err(parser->device, "usage index exceeded\n");
+		return -1;
+	}
+	parser->local.usage[parser->local.usage_index] = usage;
+
+	/*
+	 * If Usage item only includes usage id, concatenate it with
+	 * currently defined usage page
+	 */
+	if (size <= 2)
+		complete_usage(parser, parser->local.usage_index);
+
+	parser->local.usage_size[parser->local.usage_index] = size;
+	parser->local.collection_index[parser->local.usage_index] =
+		parser->collection_stack_ptr ?
+		parser->collection_stack[parser->collection_stack_ptr - 1] : 0;
+	parser->local.usage_index++;
+	return 0;
+}
+
+/*
+ * Register a new field for this report.
+ */
+
+static int hid_add_field(struct hid_parser *parser, unsigned report_type, unsigned flags)
+{
+	struct hid_report *report;
+	struct hid_field *field;
+	unsigned int max_buffer_size = HID_MAX_BUFFER_SIZE;
+	unsigned int usages;
+	unsigned int offset;
+	unsigned int i;
+	unsigned int application;
+
+	application = hid_lookup_collection(parser, HID_COLLECTION_APPLICATION);
+
+	report = hid_register_report(parser->device, report_type,
+				     parser->global.report_id, application);
+	if (!report) {
+		hid_err(parser->device, "hid_register_report failed\n");
+		return -1;
+	}
+
+	/* Handle both signed and unsigned cases properly */
+	if ((parser->global.logical_minimum < 0 &&
+		parser->global.logical_maximum <
+		parser->global.logical_minimum) ||
+		(parser->global.logical_minimum >= 0 &&
+		(__u32)parser->global.logical_maximum <
+		(__u32)parser->global.logical_minimum)) {
+		dbg_hid("logical range invalid 0x%x 0x%x\n",
+			parser->global.logical_minimum,
+			parser->global.logical_maximum);
+		return -1;
+	}
+
+	offset = report->size;
+	report->size += parser->global.report_size * parser->global.report_count;
+
+	if (parser->device->ll_driver->max_buffer_size)
+		max_buffer_size = parser->device->ll_driver->max_buffer_size;
+
+	/* Total size check: Allow for possible report index byte */
+	if (report->size > (max_buffer_size - 1) << 3) {
+		hid_err(parser->device, "report is too long\n");
+		return -1;
+	}
+
+	if (!parser->local.usage_index) /* Ignore padding fields */
+		return 0;
+
+	usages = max_t(unsigned, parser->local.usage_index,
+				 parser->global.report_count);
+
+	field = hid_register_field(report, usages);
+	if (!field)
+		return 0;
+
+	field->physical = hid_lookup_collection(parser, HID_COLLECTION_PHYSICAL);
+	field->logical = hid_lookup_collection(parser, HID_COLLECTION_LOGICAL);
+	field->application = application;
+
+	for (i = 0; i < usages; i++) {
+		unsigned j = i;
+		/* Duplicate the last usage we parsed if we have excess values */
+		if (i >= parser->local.usage_index)
+			j = parser->local.usage_index - 1;
+		field->usage[i].hid = parser->local.usage[j];
+		field->usage[i].collection_index =
+			parser->local.collection_index[j];
+		field->usage[i].usage_index = i;
+		field->usage[i].resolution_multiplier = 1;
+	}
+
+	field->maxusage = usages;
+	field->flags = flags;
+	field->report_offset = offset;
+	field->report_type = report_type;
+	field->report_size = parser->global.report_size;
+	field->report_count = parser->global.report_count;
+	field->logical_minimum = parser->global.logical_minimum;
+	field->logical_maximum = parser->global.logical_maximum;
+	field->physical_minimum = parser->global.physical_minimum;
+	field->physical_maximum = parser->global.physical_maximum;
+	field->unit_exponent = parser->global.unit_exponent;
+	field->unit = parser->global.unit;
+
+	return 0;
+}
+
+/*
+ * Read data value from item.
+ */
+
+static u32 item_udata(struct hid_item *item)
+{
+	switch (item->size) {
+	case 1: return item->data.u8;
+	case 2: return item->data.u16;
+	case 4: return item->data.u32;
+	}
+	return 0;
+}
+
+static s32 item_sdata(struct hid_item *item)
+{
+	switch (item->size) {
+	case 1: return item->data.s8;
+	case 2: return item->data.s16;
+	case 4: return item->data.s32;
+	}
+	return 0;
+}
+
+/*
+ * Process a global item.
+ */
+
+static int hid_parser_global(struct hid_parser *parser, struct hid_item *item)
+{
+	__s32 raw_value;
+	switch (item->tag) {
+	case HID_GLOBAL_ITEM_TAG_PUSH:
+
+		if (parser->global_stack_ptr == HID_GLOBAL_STACK_SIZE) {
+			hid_err(parser->device, "global environment stack overflow\n");
+			return -1;
+		}
+
+		memcpy(parser->global_stack + parser->global_stack_ptr++,
+			&parser->global, sizeof(struct hid_global));
+		return 0;
+
+	case HID_GLOBAL_ITEM_TAG_POP:
+
+		if (!parser->global_stack_ptr) {
+			hid_err(parser->device, "global environment stack underflow\n");
+			return -1;
+		}
+
+		memcpy(&parser->global, parser->global_stack +
+			--parser->global_stack_ptr, sizeof(struct hid_global));
+		return 0;
+
+	case HID_GLOBAL_ITEM_TAG_USAGE_PAGE:
+		parser->global.usage_page = item_udata(item);
+		return 0;
+
+	case HID_GLOBAL_ITEM_TAG_LOGICAL_MINIMUM:
+		parser->global.logical_minimum = item_sdata(item);
+		return 0;
+
+	case HID_GLOBAL_ITEM_TAG_LOGICAL_MAXIMUM:
+		if (parser->global.logical_minimum < 0)
+			parser->global.logical_maximum = item_sdata(item);
+		else
+			parser->global.logical_maximum = item_udata(item);
+		return 0;
+
+	case HID_GLOBAL_ITEM_TAG_PHYSICAL_MINIMUM:
+		parser->global.physical_minimum = item_sdata(item);
+		return 0;
+
+	case HID_GLOBAL_ITEM_TAG_PHYSICAL_MAXIMUM:
+		if (parser->global.physical_minimum < 0)
+			parser->global.physical_maximum = item_sdata(item);
+		else
+			parser->global.physical_maximum = item_udata(item);
+		return 0;
+
+	case HID_GLOBAL_ITEM_TAG_UNIT_EXPONENT:
+		/* Many devices provide unit exponent as a two's complement
+		 * nibble due to the common misunderstanding of HID
+		 * specification 1.11, 6.2.2.7 Global Items. Attempt to handle
+		 * both this and the standard encoding. */
+		raw_value = item_sdata(item);
+		if (!(raw_value & 0xfffffff0))
+			parser->global.unit_exponent = hid_snto32(raw_value, 4);
+		else
+			parser->global.unit_exponent = raw_value;
+		return 0;
+
+	case HID_GLOBAL_ITEM_TAG_UNIT:
+		parser->global.unit = item_udata(item);
+		return 0;
+
+	case HID_GLOBAL_ITEM_TAG_REPORT_SIZE:
+		parser->global.report_size = item_udata(item);
+		if (parser->global.report_size > 256) {
+			hid_err(parser->device, "invalid report_size %d\n",
+					parser->global.report_size);
+			return -1;
+		}
+		return 0;
+
+	case HID_GLOBAL_ITEM_TAG_REPORT_COUNT:
+		parser->global.report_count = item_udata(item);
+		if (parser->global.report_count > HID_MAX_USAGES) {
+			hid_err(parser->device, "invalid report_count %d\n",
+					parser->global.report_count);
+			return -1;
+		}
+		return 0;
+
+	case HID_GLOBAL_ITEM_TAG_REPORT_ID:
+		parser->global.report_id = item_udata(item);
+		if (parser->global.report_id == 0 ||
+		    parser->global.report_id >= HID_MAX_IDS) {
+			hid_err(parser->device, "report_id %u is invalid\n",
+				parser->global.report_id);
+			return -1;
+		}
+		return 0;
+
+	default:
+		hid_err(parser->device, "unknown global tag 0x%x\n", item->tag);
+		return -1;
+	}
+}
+
+/*
+ * Process a local item.
+ */
+
+static int hid_parser_local(struct hid_parser *parser, struct hid_item *item)
+{
+	__u32 data;
+	unsigned n;
+	__u32 count;
+
+	data = item_udata(item);
+
+	switch (item->tag) {
+	case HID_LOCAL_ITEM_TAG_DELIMITER:
+
+		if (data) {
+			/*
+			 * We treat items before the first delimiter
+			 * as global to all usage sets (branch 0).
+			 * In the moment we process only these global
+			 * items and the first delimiter set.
+			 */
+			if (parser->local.delimiter_depth != 0) {
+				hid_err(parser->device, "nested delimiters\n");
+				return -1;
+			}
+			parser->local.delimiter_depth++;
+			parser->local.delimiter_branch++;
+		} else {
+			if (parser->local.delimiter_depth < 1) {
+				hid_err(parser->device, "bogus close delimiter\n");
+				return -1;
+			}
+			parser->local.delimiter_depth--;
+		}
+		return 0;
+
+	case HID_LOCAL_ITEM_TAG_USAGE:
+
+		if (parser->local.delimiter_branch > 1) {
+			dbg_hid("alternative usage ignored\n");
+			return 0;
+		}
+
+		return hid_add_usage(parser, data, item->size);
+
+	case HID_LOCAL_ITEM_TAG_USAGE_MINIMUM:
+
+		if (parser->local.delimiter_branch > 1) {
+			dbg_hid("alternative usage ignored\n");
+			return 0;
+		}
+
+		parser->local.usage_minimum = data;
+		return 0;
+
+	case HID_LOCAL_ITEM_TAG_USAGE_MAXIMUM:
+
+		if (parser->local.delimiter_branch > 1) {
+			dbg_hid("alternative usage ignored\n");
+			return 0;
+		}
+
+		count = data - parser->local.usage_minimum;
+		if (count + parser->local.usage_index >= HID_MAX_USAGES) {
+			/*
+			 * We do not warn if the name is not set, we are
+			 * actually pre-scanning the device.
+			 */
+			if (dev_name(&parser->device->dev))
+				hid_warn(parser->device,
+					 "ignoring exceeding usage max\n");
+			data = HID_MAX_USAGES - parser->local.usage_index +
+				parser->local.usage_minimum - 1;
+			if (data <= 0) {
+				hid_err(parser->device,
+					"no more usage index available\n");
+				return -1;
+			}
+		}
+
+		for (n = parser->local.usage_minimum; n <= data; n++)
+			if (hid_add_usage(parser, n, item->size)) {
+				dbg_hid("hid_add_usage failed\n");
+				return -1;
+			}
+		return 0;
+
+	default:
+
+		dbg_hid("unknown local item tag 0x%x\n", item->tag);
+		return 0;
+	}
+	return 0;
+}
+
+/*
+ * Concatenate Usage Pages into Usages where relevant:
+ * As per specification, 6.2.2.8: "When the parser encounters a main item it
+ * concatenates the last declared Usage Page with a Usage to form a complete
+ * usage value."
+ */
+
+static void hid_concatenate_last_usage_page(struct hid_parser *parser)
+{
+	int i;
+	unsigned int usage_page;
+	unsigned int current_page;
+
+	if (!parser->local.usage_index)
+		return;
+
+	usage_page = parser->global.usage_page;
+
+	/*
+	 * Concatenate usage page again only if last declared Usage Page
+	 * has not been already used in previous usages concatenation
+	 */
+	for (i = parser->local.usage_index - 1; i >= 0; i--) {
+		if (parser->local.usage_size[i] > 2)
+			/* Ignore extended usages */
+			continue;
+
+		current_page = parser->local.usage[i] >> 16;
+		if (current_page == usage_page)
+			break;
+
+		complete_usage(parser, i);
+	}
+}
+
+/*
+ * Process a main item.
+ */
+
+static int hid_parser_main(struct hid_parser *parser, struct hid_item *item)
+{
+	__u32 data;
+	int ret;
+
+	hid_concatenate_last_usage_page(parser);
+
+	data = item_udata(item);
+
+	switch (item->tag) {
+	case HID_MAIN_ITEM_TAG_BEGIN_COLLECTION:
+		ret = open_collection(parser, data & 0xff);
+		break;
+	case HID_MAIN_ITEM_TAG_END_COLLECTION:
+		ret = close_collection(parser);
+		break;
+	case HID_MAIN_ITEM_TAG_INPUT:
+		ret = hid_add_field(parser, HID_INPUT_REPORT, data);
+		break;
+	case HID_MAIN_ITEM_TAG_OUTPUT:
+		ret = hid_add_field(parser, HID_OUTPUT_REPORT, data);
+		break;
+	case HID_MAIN_ITEM_TAG_FEATURE:
+		ret = hid_add_field(parser, HID_FEATURE_REPORT, data);
+		break;
+	default:
+		hid_warn(parser->device, "unknown main item tag 0x%x\n", item->tag);
+		ret = 0;
+	}
+
+	memset(&parser->local, 0, sizeof(parser->local));	/* Reset the local parser environment */
+
+	return ret;
+}
+
+/*
+ * Process a reserved item.
+ */
+
+static int hid_parser_reserved(struct hid_parser *parser, struct hid_item *item)
+{
+	dbg_hid("reserved item type, tag 0x%x\n", item->tag);
+	return 0;
+}
+
+/*
+ * Free a report and all registered fields. The field->usage and
+ * field->value table's are allocated behind the field, so we need
+ * only to free(field) itself.
+ */
+
+static void hid_free_report(struct hid_report *report)
+{
+	unsigned n;
+
+	for (n = 0; n < report->maxfield; n++)
+		kfree(report->field[n]);
+	kfree(report);
+}
+
+/*
+ * Close report. This function returns the device
+ * state to the point prior to hid_open_report().
+ */
+static void hid_close_report(struct hid_device *device)
+{
+	unsigned i, j;
+
+	for (i = 0; i < HID_REPORT_TYPES; i++) {
+		struct hid_report_enum *report_enum = device->report_enum + i;
+
+		for (j = 0; j < HID_MAX_IDS; j++) {
+			struct hid_report *report = report_enum->report_id_hash[j];
+			if (report)
+				hid_free_report(report);
+		}
+		memset(report_enum, 0, sizeof(*report_enum));
+		INIT_LIST_HEAD(&report_enum->report_list);
+	}
+
+	kfree(device->rdesc);
+	device->rdesc = NULL;
+	device->rsize = 0;
+
+	kfree(device->collection);
+	device->collection = NULL;
+	device->collection_size = 0;
+	device->maxcollection = 0;
+	device->maxapplication = 0;
+
+	device->status &= ~HID_STAT_PARSED;
+}
+
+/*
+ * Free a device structure, all reports, and all fields.
+ */
+
+void hiddev_free(struct kref *ref)
+{
+	struct hid_device *hid = container_of(ref, struct hid_device, ref);
+
+	hid_close_report(hid);
+	kfree(hid->dev_rdesc);
+	kfree(hid);
+}
+
+static void hid_device_release(struct device *dev)
+{
+	struct hid_device *hid = to_hid_device(dev);
+
+	kref_put(&hid->ref, hiddev_free);
+}
+
+/*
+ * Fetch a report description item from the data stream. We support long
+ * items, though they are not used yet.
+ */
+
+static u8 *fetch_item(__u8 *start, __u8 *end, struct hid_item *item)
+{
+	u8 b;
+
+	if ((end - start) <= 0)
+		return NULL;
+
+	b = *start++;
+
+	item->type = (b >> 2) & 3;
+	item->tag  = (b >> 4) & 15;
+
+	if (item->tag == HID_ITEM_TAG_LONG) {
+
+		item->format = HID_ITEM_FORMAT_LONG;
+
+		if ((end - start) < 2)
+			return NULL;
+
+		item->size = *start++;
+		item->tag  = *start++;
+
+		if ((end - start) < item->size)
+			return NULL;
+
+		item->data.longdata = start;
+		start += item->size;
+		return start;
+	}
+
+	item->format = HID_ITEM_FORMAT_SHORT;
+	item->size = b & 3;
+
+	switch (item->size) {
+	case 0:
+		return start;
+
+	case 1:
+		if ((end - start) < 1)
+			return NULL;
+		item->data.u8 = *start++;
+		return start;
+
+	case 2:
+		if ((end - start) < 2)
+			return NULL;
+		item->data.u16 = get_unaligned_le16(start);
+		start = (__u8 *)((__le16 *)start + 1);
+		return start;
+
+	case 3:
+		item->size++;
+		if ((end - start) < 4)
+			return NULL;
+		item->data.u32 = get_unaligned_le32(start);
+		start = (__u8 *)((__le32 *)start + 1);
+		return start;
+	}
+
+	return NULL;
+}
+
+static void hid_scan_input_usage(struct hid_parser *parser, u32 usage)
+{
+	struct hid_device *hid = parser->device;
+
+	if (usage == HID_DG_CONTACTID)
+		hid->group = HID_GROUP_MULTITOUCH;
+}
+
+static void hid_scan_feature_usage(struct hid_parser *parser, u32 usage)
+{
+	if (usage == 0xff0000c5 && parser->global.report_count == 256 &&
+	    parser->global.report_size == 8)
+		parser->scan_flags |= HID_SCAN_FLAG_MT_WIN_8;
+
+	if (usage == 0xff0000c6 && parser->global.report_count == 1 &&
+	    parser->global.report_size == 8)
+		parser->scan_flags |= HID_SCAN_FLAG_MT_WIN_8;
+}
+
+static void hid_scan_collection(struct hid_parser *parser, unsigned type)
+{
+	struct hid_device *hid = parser->device;
+	int i;
+
+	if (((parser->global.usage_page << 16) == HID_UP_SENSOR) &&
+	    type == HID_COLLECTION_PHYSICAL)
+		hid->group = HID_GROUP_SENSOR_HUB;
+
+	if (hid->vendor == USB_VENDOR_ID_MICROSOFT &&
+	    hid->product == USB_DEVICE_ID_MS_POWER_COVER &&
+	    hid->group == HID_GROUP_MULTITOUCH)
+		hid->group = HID_GROUP_GENERIC;
+
+	if ((parser->global.usage_page << 16) == HID_UP_GENDESK)
+		for (i = 0; i < parser->local.usage_index; i++)
+			if (parser->local.usage[i] == HID_GD_POINTER)
+				parser->scan_flags |= HID_SCAN_FLAG_GD_POINTER;
+
+	if ((parser->global.usage_page << 16) >= HID_UP_MSVENDOR)
+		parser->scan_flags |= HID_SCAN_FLAG_VENDOR_SPECIFIC;
+
+	if ((parser->global.usage_page << 16) == HID_UP_GOOGLEVENDOR)
+		for (i = 0; i < parser->local.usage_index; i++)
+			if (parser->local.usage[i] ==
+					(HID_UP_GOOGLEVENDOR | 0x0001))
+				parser->device->group =
+					HID_GROUP_VIVALDI;
+}
+
+static int hid_scan_main(struct hid_parser *parser, struct hid_item *item)
+{
+	__u32 data;
+	int i;
+
+	hid_concatenate_last_usage_page(parser);
+
+	data = item_udata(item);
+
+	switch (item->tag) {
+	case HID_MAIN_ITEM_TAG_BEGIN_COLLECTION:
+		hid_scan_collection(parser, data & 0xff);
+		break;
+	case HID_MAIN_ITEM_TAG_END_COLLECTION:
+		break;
+	case HID_MAIN_ITEM_TAG_INPUT:
+		/* ignore constant inputs, they will be ignored by hid-input */
+		if (data & HID_MAIN_ITEM_CONSTANT)
+			break;
+		for (i = 0; i < parser->local.usage_index; i++)
+			hid_scan_input_usage(parser, parser->local.usage[i]);
+		break;
+	case HID_MAIN_ITEM_TAG_OUTPUT:
+		break;
+	case HID_MAIN_ITEM_TAG_FEATURE:
+		for (i = 0; i < parser->local.usage_index; i++)
+			hid_scan_feature_usage(parser, parser->local.usage[i]);
+		break;
+	}
+
+	/* Reset the local parser environment */
+	memset(&parser->local, 0, sizeof(parser->local));
+
+	return 0;
+}
+
+/*
+ * Scan a report descriptor before the device is added to the bus.
+ * Sets device groups and other properties that determine what driver
+ * to load.
+ */
+static int hid_scan_report(struct hid_device *hid)
+{
+	struct hid_parser *parser;
+	struct hid_item item;
+	__u8 *start = hid->dev_rdesc;
+	__u8 *end = start + hid->dev_rsize;
+	static int (*dispatch_type[])(struct hid_parser *parser,
+				      struct hid_item *item) = {
+		hid_scan_main,
+		hid_parser_global,
+		hid_parser_local,
+		hid_parser_reserved
+	};
+
+	parser = vzalloc(sizeof(struct hid_parser));
+	if (!parser)
+		return -ENOMEM;
+
+	parser->device = hid;
+	hid->group = HID_GROUP_GENERIC;
+
+	/*
+	 * The parsing is simpler than the one in hid_open_report() as we should
+	 * be robust against hid errors. Those errors will be raised by
+	 * hid_open_report() anyway.
+	 */
+	while ((start = fetch_item(start, end, &item)) != NULL)
+		dispatch_type[item.type](parser, &item);
+
+	/*
+	 * Handle special flags set during scanning.
+	 */
+	if ((parser->scan_flags & HID_SCAN_FLAG_MT_WIN_8) &&
+	    (hid->group == HID_GROUP_MULTITOUCH))
+		hid->group = HID_GROUP_MULTITOUCH_WIN_8;
+
+	/*
+	 * Vendor specific handlings
+	 */
+	switch (hid->vendor) {
+	case USB_VENDOR_ID_WACOM:
+		hid->group = HID_GROUP_WACOM;
+		break;
+	case USB_VENDOR_ID_SYNAPTICS:
+		if (hid->group == HID_GROUP_GENERIC)
+			if ((parser->scan_flags & HID_SCAN_FLAG_VENDOR_SPECIFIC)
+			    && (parser->scan_flags & HID_SCAN_FLAG_GD_POINTER))
+				/*
+				 * hid-rmi should take care of them,
+				 * not hid-generic
+				 */
+				hid->group = HID_GROUP_RMI;
+		break;
+	}
+
+	kfree(parser->collection_stack);
+	vfree(parser);
+	return 0;
+}
+
+/**
+ * hid_parse_report - parse device report
+ *
+ * @hid: hid device
+ * @start: report start
+ * @size: report size
+ *
+ * Allocate the device report as read by the bus driver. This function should
+ * only be called from parse() in ll drivers.
+ */
+int hid_parse_report(struct hid_device *hid, __u8 *start, unsigned size)
+{
+	hid->dev_rdesc = kmemdup(start, size, GFP_KERNEL);
+	if (!hid->dev_rdesc)
+		return -ENOMEM;
+	hid->dev_rsize = size;
+	return 0;
+}
+EXPORT_SYMBOL_GPL(hid_parse_report);
+
+static const char * const hid_report_names[] = {
+	"HID_INPUT_REPORT",
+	"HID_OUTPUT_REPORT",
+	"HID_FEATURE_REPORT",
+};
+/**
+ * hid_validate_values - validate existing device report's value indexes
+ *
+ * @hid: hid device
+ * @type: which report type to examine
+ * @id: which report ID to examine (0 for first)
+ * @field_index: which report field to examine
+ * @report_counts: expected number of values
+ *
+ * Validate the number of values in a given field of a given report, after
+ * parsing.
+ */
+struct hid_report *hid_validate_values(struct hid_device *hid,
+				       unsigned int type, unsigned int id,
+				       unsigned int field_index,
+				       unsigned int report_counts)
+{
+	struct hid_report *report;
+
+	if (type > HID_FEATURE_REPORT) {
+		hid_err(hid, "invalid HID report type %u\n", type);
+		return NULL;
+	}
+
+	if (id >= HID_MAX_IDS) {
+		hid_err(hid, "invalid HID report id %u\n", id);
+		return NULL;
+	}
+
+	/*
+	 * Explicitly not using hid_get_report() here since it depends on
+	 * ->numbered being checked, which may not always be the case when
+	 * drivers go to access report values.
+	 */
+	if (id == 0) {
+		/*
+		 * Validating on id 0 means we should examine the first
+		 * report in the list.
+		 */
+		report = list_first_entry_or_null(
+				&hid->report_enum[type].report_list,
+				struct hid_report, list);
+	} else {
+		report = hid->report_enum[type].report_id_hash[id];
+	}
+	if (!report) {
+		hid_err(hid, "missing %s %u\n", hid_report_names[type], id);
+		return NULL;
+	}
+	if (report->maxfield <= field_index) {
+		hid_err(hid, "not enough fields in %s %u\n",
+			hid_report_names[type], id);
+		return NULL;
+	}
+	if (report->field[field_index]->report_count < report_counts) {
+		hid_err(hid, "not enough values in %s %u field %u\n",
+			hid_report_names[type], id, field_index);
+		return NULL;
+	}
+	return report;
+}
+EXPORT_SYMBOL_GPL(hid_validate_values);
+
+static int hid_calculate_multiplier(struct hid_device *hid,
+				     struct hid_field *multiplier)
+{
+	int m;
+	__s32 v = *multiplier->value;
+	__s32 lmin = multiplier->logical_minimum;
+	__s32 lmax = multiplier->logical_maximum;
+	__s32 pmin = multiplier->physical_minimum;
+	__s32 pmax = multiplier->physical_maximum;
+
+	/*
+	 * "Because OS implementations will generally divide the control's
+	 * reported count by the Effective Resolution Multiplier, designers
+	 * should take care not to establish a potential Effective
+	 * Resolution Multiplier of zero."
+	 * HID Usage Table, v1.12, Section 4.3.1, p31
+	 */
+	if (lmax - lmin == 0)
+		return 1;
+	/*
+	 * Handling the unit exponent is left as an exercise to whoever
+	 * finds a device where that exponent is not 0.
+	 */
+	m = ((v - lmin)/(lmax - lmin) * (pmax - pmin) + pmin);
+	if (unlikely(multiplier->unit_exponent != 0)) {
+		hid_warn(hid,
+			 "unsupported Resolution Multiplier unit exponent %d\n",
+			 multiplier->unit_exponent);
+	}
+
+	/* There are no devices with an effective multiplier > 255 */
+	if (unlikely(m == 0 || m > 255 || m < -255)) {
+		hid_warn(hid, "unsupported Resolution Multiplier %d\n", m);
+		m = 1;
+	}
+
+	return m;
+}
+
+static void hid_apply_multiplier_to_field(struct hid_device *hid,
+					  struct hid_field *field,
+					  struct hid_collection *multiplier_collection,
+					  int effective_multiplier)
+{
+	struct hid_collection *collection;
+	struct hid_usage *usage;
+	int i;
+
+	/*
+	 * If multiplier_collection is NULL, the multiplier applies
+	 * to all fields in the report.
+	 * Otherwise, it is the Logical Collection the multiplier applies to
+	 * but our field may be in a subcollection of that collection.
+	 */
+	for (i = 0; i < field->maxusage; i++) {
+		usage = &field->usage[i];
+
+		collection = &hid->collection[usage->collection_index];
+		while (collection->parent_idx != -1 &&
+		       collection != multiplier_collection)
+			collection = &hid->collection[collection->parent_idx];
+
+		if (collection->parent_idx != -1 ||
+		    multiplier_collection == NULL)
+			usage->resolution_multiplier = effective_multiplier;
+
+	}
+}
+
+static void hid_apply_multiplier(struct hid_device *hid,
+				 struct hid_field *multiplier)
+{
+	struct hid_report_enum *rep_enum;
+	struct hid_report *rep;
+	struct hid_field *field;
+	struct hid_collection *multiplier_collection;
+	int effective_multiplier;
+	int i;
+
+	/*
+	 * "The Resolution Multiplier control must be contained in the same
+	 * Logical Collection as the control(s) to which it is to be applied.
+	 * If no Resolution Multiplier is defined, then the Resolution
+	 * Multiplier defaults to 1.  If more than one control exists in a
+	 * Logical Collection, the Resolution Multiplier is associated with
+	 * all controls in the collection. If no Logical Collection is
+	 * defined, the Resolution Multiplier is associated with all
+	 * controls in the report."
+	 * HID Usage Table, v1.12, Section 4.3.1, p30
+	 *
+	 * Thus, search from the current collection upwards until we find a
+	 * logical collection. Then search all fields for that same parent
+	 * collection. Those are the fields the multiplier applies to.
+	 *
+	 * If we have more than one multiplier, it will overwrite the
+	 * applicable fields later.
+	 */
+	multiplier_collection = &hid->collection[multiplier->usage->collection_index];
+	while (multiplier_collection->parent_idx != -1 &&
+	       multiplier_collection->type != HID_COLLECTION_LOGICAL)
+		multiplier_collection = &hid->collection[multiplier_collection->parent_idx];
+
+	effective_multiplier = hid_calculate_multiplier(hid, multiplier);
+
+	rep_enum = &hid->report_enum[HID_INPUT_REPORT];
+	list_for_each_entry(rep, &rep_enum->report_list, list) {
+		for (i = 0; i < rep->maxfield; i++) {
+			field = rep->field[i];
+			hid_apply_multiplier_to_field(hid, field,
+						      multiplier_collection,
+						      effective_multiplier);
+		}
+	}
+}
+
+/*
+ * hid_setup_resolution_multiplier - set up all resolution multipliers
+ *
+ * @device: hid device
+ *
+ * Search for all Resolution Multiplier Feature Reports and apply their
+ * value to all matching Input items. This only updates the internal struct
+ * fields.
+ *
+ * The Resolution Multiplier is applied by the hardware. If the multiplier
+ * is anything other than 1, the hardware will send pre-multiplied events
+ * so that the same physical interaction generates an accumulated
+ *	accumulated_value = value * * multiplier
+ * This may be achieved by sending
+ * - "value * multiplier" for each event, or
+ * - "value" but "multiplier" times as frequently, or
+ * - a combination of the above
+ * The only guarantee is that the same physical interaction always generates
+ * an accumulated 'value * multiplier'.
+ *
+ * This function must be called before any event processing and after
+ * any SetRequest to the Resolution Multiplier.
+ */
+void hid_setup_resolution_multiplier(struct hid_device *hid)
+{
+	struct hid_report_enum *rep_enum;
+	struct hid_report *rep;
+	struct hid_usage *usage;
+	int i, j;
+
+	rep_enum = &hid->report_enum[HID_FEATURE_REPORT];
+	list_for_each_entry(rep, &rep_enum->report_list, list) {
+		for (i = 0; i < rep->maxfield; i++) {
+			/* Ignore if report count is out of bounds. */
+			if (rep->field[i]->report_count < 1)
+				continue;
+
+			for (j = 0; j < rep->field[i]->maxusage; j++) {
+				usage = &rep->field[i]->usage[j];
+				if (usage->hid == HID_GD_RESOLUTION_MULTIPLIER)
+					hid_apply_multiplier(hid,
+							     rep->field[i]);
+			}
+		}
+	}
+}
+EXPORT_SYMBOL_GPL(hid_setup_resolution_multiplier);
+
+/**
+ * hid_open_report - open a driver-specific device report
+ *
+ * @device: hid device
+ *
+ * Parse a report description into a hid_device structure. Reports are
+ * enumerated, fields are attached to these reports.
+ * 0 returned on success, otherwise nonzero error value.
+ *
+ * This function (or the equivalent hid_parse() macro) should only be
+ * called from probe() in drivers, before starting the device.
+ */
+int hid_open_report(struct hid_device *device)
+{
+	struct hid_parser *parser;
+	struct hid_item item;
+	unsigned int size;
+	__u8 *start;
+	__u8 *buf;
+	__u8 *end;
+	__u8 *next;
+	int ret;
+	int i;
+	static int (*dispatch_type[])(struct hid_parser *parser,
+				      struct hid_item *item) = {
+		hid_parser_main,
+		hid_parser_global,
+		hid_parser_local,
+		hid_parser_reserved
+	};
+
+	if (WARN_ON(device->status & HID_STAT_PARSED))
+		return -EBUSY;
+
+	start = device->dev_rdesc;
+	if (WARN_ON(!start))
+		return -ENODEV;
+	size = device->dev_rsize;
+
+	buf = kmemdup(start, size, GFP_KERNEL);
+	if (buf == NULL)
+		return -ENOMEM;
+
+	if (device->driver->report_fixup)
+		start = device->driver->report_fixup(device, buf, &size);
+	else
+		start = buf;
+
+	start = kmemdup(start, size, GFP_KERNEL);
+	kfree(buf);
+	if (start == NULL)
+		return -ENOMEM;
+
+	device->rdesc = start;
+	device->rsize = size;
+
+	parser = vzalloc(sizeof(struct hid_parser));
+	if (!parser) {
+		ret = -ENOMEM;
+		goto alloc_err;
+	}
+
+	parser->device = device;
+
+	end = start + size;
+
+	device->collection = kcalloc(HID_DEFAULT_NUM_COLLECTIONS,
+				     sizeof(struct hid_collection), GFP_KERNEL);
+	if (!device->collection) {
+		ret = -ENOMEM;
+		goto err;
+	}
+	device->collection_size = HID_DEFAULT_NUM_COLLECTIONS;
+	for (i = 0; i < HID_DEFAULT_NUM_COLLECTIONS; i++)
+		device->collection[i].parent_idx = -1;
+
+	ret = -EINVAL;
+	while ((next = fetch_item(start, end, &item)) != NULL) {
+		start = next;
+
+		if (item.format != HID_ITEM_FORMAT_SHORT) {
+			hid_err(device, "unexpected long global item\n");
+			goto err;
+		}
+
+		if (dispatch_type[item.type](parser, &item)) {
+			hid_err(device, "item %u %u %u %u parsing failed\n",
+				item.format, (unsigned)item.size,
+				(unsigned)item.type, (unsigned)item.tag);
+			goto err;
+		}
+
+		if (start == end) {
+			if (parser->collection_stack_ptr) {
+				hid_err(device, "unbalanced collection at end of report description\n");
+				goto err;
+			}
+			if (parser->local.delimiter_depth) {
+				hid_err(device, "unbalanced delimiter at end of report description\n");
+				goto err;
+			}
+
+			/*
+			 * fetch initial values in case the device's
+			 * default multiplier isn't the recommended 1
+			 */
+			hid_setup_resolution_multiplier(device);
+
+			kfree(parser->collection_stack);
+			vfree(parser);
+			device->status |= HID_STAT_PARSED;
+
+			return 0;
+		}
+	}
+
+	hid_err(device, "item fetching failed at offset %u/%u\n",
+		size - (unsigned int)(end - start), size);
+err:
+	kfree(parser->collection_stack);
+alloc_err:
+	vfree(parser);
+	hid_close_report(device);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(hid_open_report);
+
+/*
+ * Convert a signed n-bit integer to signed 32-bit integer. Common
+ * cases are done through the compiler, the screwed things has to be
+ * done by hand.
+ */
+
+static s32 snto32(__u32 value, unsigned n)
+{
+	if (!value || !n)
+		return 0;
+
+	if (n > 32)
+		n = 32;
+
+	switch (n) {
+	case 8:  return ((__s8)value);
+	case 16: return ((__s16)value);
+	case 32: return ((__s32)value);
+	}
+	return value & (1 << (n - 1)) ? value | (~0U << n) : value;
+}
+
+s32 hid_snto32(__u32 value, unsigned n)
+{
+	return snto32(value, n);
+}
+EXPORT_SYMBOL_GPL(hid_snto32);
+
+/*
+ * Convert a signed 32-bit integer to a signed n-bit integer.
+ */
+
+static u32 s32ton(__s32 value, unsigned n)
+{
+	s32 a = value >> (n - 1);
+	if (a && a != -1)
+		return value < 0 ? 1 << (n - 1) : (1 << (n - 1)) - 1;
+	return value & ((1 << n) - 1);
+}
+
+/*
+ * Extract/implement a data field from/to a little endian report (bit array).
+ *
+ * Code sort-of follows HID spec:
+ *     http://www.usb.org/developers/hidpage/HID1_11.pdf
+ *
+ * While the USB HID spec allows unlimited length bit fields in "report
+ * descriptors", most devices never use more than 16 bits.
+ * One model of UPS is claimed to report "LINEV" as a 32-bit field.
+ * Search linux-kernel and linux-usb-devel archives for "hid-core extract".
+ */
+
+static u32 __extract(u8 *report, unsigned offset, int n)
+{
+	unsigned int idx = offset / 8;
+	unsigned int bit_nr = 0;
+	unsigned int bit_shift = offset % 8;
+	int bits_to_copy = 8 - bit_shift;
+	u32 value = 0;
+	u32 mask = n < 32 ? (1U << n) - 1 : ~0U;
+
+	while (n > 0) {
+		value |= ((u32)report[idx] >> bit_shift) << bit_nr;
+		n -= bits_to_copy;
+		bit_nr += bits_to_copy;
+		bits_to_copy = 8;
+		bit_shift = 0;
+		idx++;
+	}
+
+	return value & mask;
+}
+
+u32 hid_field_extract(const struct hid_device *hid, u8 *report,
+			unsigned offset, unsigned n)
+{
+	if (n > 32) {
+		hid_warn_once(hid, "%s() called with n (%d) > 32! (%s)\n",
+			      __func__, n, current->comm);
+		n = 32;
+	}
+
+	return __extract(report, offset, n);
+}
+EXPORT_SYMBOL_GPL(hid_field_extract);
+
+/*
+ * "implement" : set bits in a little endian bit stream.
+ * Same concepts as "extract" (see comments above).
+ * The data mangled in the bit stream remains in little endian
+ * order the whole time. It make more sense to talk about
+ * endianness of register values by considering a register
+ * a "cached" copy of the little endian bit stream.
+ */
+
+static void __implement(u8 *report, unsigned offset, int n, u32 value)
+{
+	unsigned int idx = offset / 8;
+	unsigned int bit_shift = offset % 8;
+	int bits_to_set = 8 - bit_shift;
+
+	while (n - bits_to_set >= 0) {
+		report[idx] &= ~(0xff << bit_shift);
+		report[idx] |= value << bit_shift;
+		value >>= bits_to_set;
+		n -= bits_to_set;
+		bits_to_set = 8;
+		bit_shift = 0;
+		idx++;
+	}
+
+	/* last nibble */
+	if (n) {
+		u8 bit_mask = ((1U << n) - 1);
+		report[idx] &= ~(bit_mask << bit_shift);
+		report[idx] |= value << bit_shift;
+	}
+}
+
+static void implement(const struct hid_device *hid, u8 *report,
+		      unsigned offset, unsigned n, u32 value)
+{
+	if (unlikely(n > 32)) {
+		hid_warn(hid, "%s() called with n (%d) > 32! (%s)\n",
+			 __func__, n, current->comm);
+		n = 32;
+	} else if (n < 32) {
+		u32 m = (1U << n) - 1;
+
+		if (unlikely(value > m)) {
+			hid_warn(hid,
+				 "%s() called with too large value %d (n: %d)! (%s)\n",
+				 __func__, value, n, current->comm);
+			WARN_ON(1);
+			value &= m;
+		}
+	}
+
+	__implement(report, offset, n, value);
+}
+
+/*
+ * Search an array for a value.
+ */
+
+static int search(__s32 *array, __s32 value, unsigned n)
+{
+	while (n--) {
+		if (*array++ == value)
+			return 0;
+	}
+	return -1;
+}
+
+/**
+ * hid_match_report - check if driver's raw_event should be called
+ *
+ * @hid: hid device
+ * @report: hid report to match against
+ *
+ * compare hid->driver->report_table->report_type to report->type
+ */
+static int hid_match_report(struct hid_device *hid, struct hid_report *report)
+{
+	const struct hid_report_id *id = hid->driver->report_table;
+
+	if (!id) /* NULL means all */
+		return 1;
+
+	for (; id->report_type != HID_TERMINATOR; id++)
+		if (id->report_type == HID_ANY_ID ||
+				id->report_type == report->type)
+			return 1;
+	return 0;
+}
+
+/**
+ * hid_match_usage - check if driver's event should be called
+ *
+ * @hid: hid device
+ * @usage: usage to match against
+ *
+ * compare hid->driver->usage_table->usage_{type,code} to
+ * usage->usage_{type,code}
+ */
+static int hid_match_usage(struct hid_device *hid, struct hid_usage *usage)
+{
+	const struct hid_usage_id *id = hid->driver->usage_table;
+
+	if (!id) /* NULL means all */
+		return 1;
+
+	for (; id->usage_type != HID_ANY_ID - 1; id++)
+		if ((id->usage_hid == HID_ANY_ID ||
+				id->usage_hid == usage->hid) &&
+				(id->usage_type == HID_ANY_ID ||
+				id->usage_type == usage->type) &&
+				(id->usage_code == HID_ANY_ID ||
+				 id->usage_code == usage->code))
+			return 1;
+	return 0;
+}
+
+static void hid_process_event(struct hid_device *hid, struct hid_field *field,
+		struct hid_usage *usage, __s32 value, int interrupt)
+{
+	struct hid_driver *hdrv = hid->driver;
+	int ret;
+
+	if (!list_empty(&hid->debug_list))
+		hid_dump_input(hid, usage, value);
+
+	if (hdrv && hdrv->event && hid_match_usage(hid, usage)) {
+		ret = hdrv->event(hid, field, usage, value);
+		if (ret != 0) {
+			if (ret < 0)
+				hid_err(hid, "%s's event failed with %d\n",
+						hdrv->name, ret);
+			return;
+		}
+	}
+
+	if (hid->claimed & HID_CLAIMED_INPUT)
+		hidinput_hid_event(hid, field, usage, value);
+	if (hid->claimed & HID_CLAIMED_HIDDEV && interrupt && hid->hiddev_hid_event)
+		hid->hiddev_hid_event(hid, field, usage, value);
+}
+
+/*
+ * Analyse a received field, and fetch the data from it. The field
+ * content is stored for next report processing (we do differential
+ * reporting to the layer).
+ */
+
+static void hid_input_field(struct hid_device *hid, struct hid_field *field,
+			    __u8 *data, int interrupt)
+{
+	unsigned n;
+	unsigned count = field->report_count;
+	unsigned offset = field->report_offset;
+	unsigned size = field->report_size;
+	__s32 min = field->logical_minimum;
+	__s32 max = field->logical_maximum;
+	__s32 *value;
+
+	value = kmalloc_array(count, sizeof(__s32), GFP_ATOMIC);
+	if (!value)
+		return;
+
+	for (n = 0; n < count; n++) {
+
+		value[n] = min < 0 ?
+			snto32(hid_field_extract(hid, data, offset + n * size,
+			       size), size) :
+			hid_field_extract(hid, data, offset + n * size, size);
+
+		/* Ignore report if ErrorRollOver */
+		if (!(field->flags & HID_MAIN_ITEM_VARIABLE) &&
+		    value[n] >= min && value[n] <= max &&
+		    value[n] - min < field->maxusage &&
+		    field->usage[value[n] - min].hid == HID_UP_KEYBOARD + 1)
+			goto exit;
+	}
+
+	for (n = 0; n < count; n++) {
+
+		if (HID_MAIN_ITEM_VARIABLE & field->flags) {
+			hid_process_event(hid, field, &field->usage[n], value[n], interrupt);
+			continue;
+		}
+
+		if (field->value[n] >= min && field->value[n] <= max
+			&& field->value[n] - min < field->maxusage
+			&& field->usage[field->value[n] - min].hid
+			&& search(value, field->value[n], count))
+				hid_process_event(hid, field, &field->usage[field->value[n] - min], 0, interrupt);
+
+		if (value[n] >= min && value[n] <= max
+			&& value[n] - min < field->maxusage
+			&& field->usage[value[n] - min].hid
+			&& search(field->value, value[n], count))
+				hid_process_event(hid, field, &field->usage[value[n] - min], 1, interrupt);
+	}
+
+	memcpy(field->value, value, count * sizeof(__s32));
+exit:
+	kfree(value);
+}
+
+/*
+ * Output the field into the report.
+ */
+
+static void hid_output_field(const struct hid_device *hid,
+			     struct hid_field *field, __u8 *data)
+{
+	unsigned count = field->report_count;
+	unsigned offset = field->report_offset;
+	unsigned size = field->report_size;
+	unsigned n;
+
+	for (n = 0; n < count; n++) {
+		if (field->logical_minimum < 0)	/* signed values */
+			implement(hid, data, offset + n * size, size,
+				  s32ton(field->value[n], size));
+		else				/* unsigned values */
+			implement(hid, data, offset + n * size, size,
+				  field->value[n]);
+	}
+}
+
+/*
+ * Compute the size of a report.
+ */
+static size_t hid_compute_report_size(struct hid_report *report)
+{
+	if (report->size)
+		return ((report->size - 1) >> 3) + 1;
+
+	return 0;
+}
+
+/*
+ * Create a report. 'data' has to be allocated using
+ * hid_alloc_report_buf() so that it has proper size.
+ */
+
+void hid_output_report(struct hid_report *report, __u8 *data)
+{
+	unsigned n;
+
+	if (report->id > 0)
+		*data++ = report->id;
+
+	memset(data, 0, hid_compute_report_size(report));
+	for (n = 0; n < report->maxfield; n++)
+		hid_output_field(report->device, report->field[n], data);
+}
+EXPORT_SYMBOL_GPL(hid_output_report);
+
+/*
+ * Allocator for buffer that is going to be passed to hid_output_report()
+ */
+u8 *hid_alloc_report_buf(struct hid_report *report, gfp_t flags)
+{
+	/*
+	 * 7 extra bytes are necessary to achieve proper functionality
+	 * of implement() working on 8 byte chunks
+	 */
+
+	u32 len = hid_report_len(report) + 7;
+
+	return kmalloc(len, flags);
+}
+EXPORT_SYMBOL_GPL(hid_alloc_report_buf);
+
+/*
+ * Set a field value. The report this field belongs to has to be
+ * created and transferred to the device, to set this value in the
+ * device.
+ */
+
+int hid_set_field(struct hid_field *field, unsigned offset, __s32 value)
+{
+	unsigned size;
+
+	if (!field)
+		return -1;
+
+	size = field->report_size;
+
+	hid_dump_input(field->report->device, field->usage + offset, value);
+
+	if (offset >= field->report_count) {
+		hid_err(field->report->device, "offset (%d) exceeds report_count (%d)\n",
+				offset, field->report_count);
+		return -1;
+	}
+	if (field->logical_minimum < 0) {
+		if (value != snto32(s32ton(value, size), size)) {
+			hid_err(field->report->device, "value %d is out of range\n", value);
+			return -1;
+		}
+	}
+	field->value[offset] = value;
+	return 0;
+}
+EXPORT_SYMBOL_GPL(hid_set_field);
+
+static struct hid_report *hid_get_report(struct hid_report_enum *report_enum,
+		const u8 *data)
+{
+	struct hid_report *report;
+	unsigned int n = 0;	/* Normally report number is 0 */
+
+	/* Device uses numbered reports, data[0] is report number */
+	if (report_enum->numbered)
+		n = *data;
+
+	report = report_enum->report_id_hash[n];
+	if (report == NULL)
+		dbg_hid("undefined report_id %u received\n", n);
+
+	return report;
+}
+
+/*
+ * Implement a generic .request() callback, using .raw_request()
+ * DO NOT USE in hid drivers directly, but through hid_hw_request instead.
+ */
+int __hid_request(struct hid_device *hid, struct hid_report *report,
+		int reqtype)
+{
+	char *buf;
+	int ret;
+	u32 len;
+
+	buf = hid_alloc_report_buf(report, GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+
+	len = hid_report_len(report);
+
+	if (reqtype == HID_REQ_SET_REPORT)
+		hid_output_report(report, buf);
+
+	ret = hid->ll_driver->raw_request(hid, report->id, buf, len,
+					  report->type, reqtype);
+	if (ret < 0) {
+		dbg_hid("unable to complete request: %d\n", ret);
+		goto out;
+	}
+
+	if (reqtype == HID_REQ_GET_REPORT)
+		hid_input_report(hid, report->type, buf, ret, 0);
+
+	ret = 0;
+
+out:
+	kfree(buf);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(__hid_request);
+
+int hid_report_raw_event(struct hid_device *hid, int type, u8 *data, u32 size,
+		int interrupt)
+{
+	struct hid_report_enum *report_enum = hid->report_enum + type;
+	struct hid_report *report;
+	struct hid_driver *hdrv;
+	int max_buffer_size = HID_MAX_BUFFER_SIZE;
+	unsigned int a;
+	u32 rsize, csize = size;
+	u8 *cdata = data;
+	int ret = 0;
+
+	report = hid_get_report(report_enum, data);
+	if (!report)
+		goto out;
+
+	if (report_enum->numbered) {
+		cdata++;
+		csize--;
+	}
+
+	rsize = hid_compute_report_size(report);
+
+	if (hid->ll_driver->max_buffer_size)
+		max_buffer_size = hid->ll_driver->max_buffer_size;
+
+	if (report_enum->numbered && rsize >= max_buffer_size)
+		rsize = max_buffer_size - 1;
+	else if (rsize > max_buffer_size)
+		rsize = max_buffer_size;
+
+	if (csize < rsize) {
+		dbg_hid("report %d is too short, (%d < %d)\n", report->id,
+				csize, rsize);
+		memset(cdata + csize, 0, rsize - csize);
+	}
+
+	if ((hid->claimed & HID_CLAIMED_HIDDEV) && hid->hiddev_report_event)
+		hid->hiddev_report_event(hid, report);
+	if (hid->claimed & HID_CLAIMED_HIDRAW) {
+		ret = hidraw_report_event(hid, data, size);
+		if (ret)
+			goto out;
+	}
+
+	if (hid->claimed != HID_CLAIMED_HIDRAW && report->maxfield) {
+		for (a = 0; a < report->maxfield; a++)
+			hid_input_field(hid, report->field[a], cdata, interrupt);
+		hdrv = hid->driver;
+		if (hdrv && hdrv->report)
+			hdrv->report(hid, report);
+	}
+
+	if (hid->claimed & HID_CLAIMED_INPUT)
+		hidinput_report_event(hid, report);
+out:
+	return ret;
+}
+EXPORT_SYMBOL_GPL(hid_report_raw_event);
+
+/**
+ * hid_input_report - report data from lower layer (usb, bt...)
+ *
+ * @hid: hid device
+ * @type: HID report type (HID_*_REPORT)
+ * @data: report contents
+ * @size: size of data parameter
+ * @interrupt: distinguish between interrupt and control transfers
+ *
+ * This is data entry for lower layers.
+ */
+int hid_input_report(struct hid_device *hid, int type, u8 *data, u32 size, int interrupt)
+{
+	struct hid_report_enum *report_enum;
+	struct hid_driver *hdrv;
+	struct hid_report *report;
+	int ret = 0;
+
+	if (!hid)
+		return -ENODEV;
+
+	if (down_trylock(&hid->driver_input_lock))
+		return -EBUSY;
+
+	if (!hid->driver) {
+		ret = -ENODEV;
+		goto unlock;
+	}
+	report_enum = hid->report_enum + type;
+	hdrv = hid->driver;
+
+	if (!size) {
+		dbg_hid("empty report\n");
+		ret = -1;
+		goto unlock;
+	}
+
+	/* Avoid unnecessary overhead if debugfs is disabled */
+	if (!list_empty(&hid->debug_list))
+		hid_dump_report(hid, type, data, size);
+
+	report = hid_get_report(report_enum, data);
+
+	if (!report) {
+		ret = -1;
+		goto unlock;
+	}
+
+	if (hdrv && hdrv->raw_event && hid_match_report(hid, report)) {
+		ret = hdrv->raw_event(hid, report, data, size);
+		if (ret < 0)
+			goto unlock;
+	}
+
+	ret = hid_report_raw_event(hid, type, data, size, interrupt);
+
+unlock:
+	up(&hid->driver_input_lock);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(hid_input_report);
+
+bool hid_match_one_id(const struct hid_device *hdev,
+		      const struct hid_device_id *id)
+{
+	return (id->bus == HID_BUS_ANY || id->bus == hdev->bus) &&
+		(id->group == HID_GROUP_ANY || id->group == hdev->group) &&
+		(id->vendor == HID_ANY_ID || id->vendor == hdev->vendor) &&
+		(id->product == HID_ANY_ID || id->product == hdev->product);
+}
+
+const struct hid_device_id *hid_match_id(const struct hid_device *hdev,
+		const struct hid_device_id *id)
+{
+	for (; id->bus; id++)
+		if (hid_match_one_id(hdev, id))
+			return id;
+
+	return NULL;
+}
+
+static const struct hid_device_id hid_hiddev_list[] = {
+	{ HID_USB_DEVICE(USB_VENDOR_ID_MGE, USB_DEVICE_ID_MGE_UPS) },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_MGE, USB_DEVICE_ID_MGE_UPS1) },
+	{ }
+};
+
+static bool hid_hiddev(struct hid_device *hdev)
+{
+	return !!hid_match_id(hdev, hid_hiddev_list);
+}
+
+
+static ssize_t
+read_report_descriptor(struct file *filp, struct kobject *kobj,
+		struct bin_attribute *attr,
+		char *buf, loff_t off, size_t count)
+{
+	struct device *dev = kobj_to_dev(kobj);
+	struct hid_device *hdev = to_hid_device(dev);
+
+	if (off >= hdev->rsize)
+		return 0;
+
+	if (off + count > hdev->rsize)
+		count = hdev->rsize - off;
+
+	memcpy(buf, hdev->rdesc + off, count);
+
+	return count;
+}
+
+static ssize_t
+show_country(struct device *dev, struct device_attribute *attr,
+		char *buf)
+{
+	struct hid_device *hdev = to_hid_device(dev);
+
+	return sprintf(buf, "%02x\n", hdev->country & 0xff);
+}
+
+static struct bin_attribute dev_bin_attr_report_desc = {
+	.attr = { .name = "report_descriptor", .mode = 0444 },
+	.read = read_report_descriptor,
+	.size = HID_MAX_DESCRIPTOR_SIZE,
+};
+
+static const struct device_attribute dev_attr_country = {
+	.attr = { .name = "country", .mode = 0444 },
+	.show = show_country,
+};
+
+int hid_connect(struct hid_device *hdev, unsigned int connect_mask)
+{
+	static const char *types[] = { "Device", "Pointer", "Mouse", "Device",
+		"Joystick", "Gamepad", "Keyboard", "Keypad",
+		"Multi-Axis Controller"
+	};
+	const char *type, *bus;
+	char buf[64] = "";
+	unsigned int i;
+	int len;
+	int ret;
+
+	if (hdev->quirks & HID_QUIRK_HIDDEV_FORCE)
+		connect_mask |= (HID_CONNECT_HIDDEV_FORCE | HID_CONNECT_HIDDEV);
+	if (hdev->quirks & HID_QUIRK_HIDINPUT_FORCE)
+		connect_mask |= HID_CONNECT_HIDINPUT_FORCE;
+	if (hdev->bus != BUS_USB)
+		connect_mask &= ~HID_CONNECT_HIDDEV;
+	if (hid_hiddev(hdev))
+		connect_mask |= HID_CONNECT_HIDDEV_FORCE;
+
+	if ((connect_mask & HID_CONNECT_HIDINPUT) && !hidinput_connect(hdev,
+				connect_mask & HID_CONNECT_HIDINPUT_FORCE))
+		hdev->claimed |= HID_CLAIMED_INPUT;
+
+	if ((connect_mask & HID_CONNECT_HIDDEV) && hdev->hiddev_connect &&
+			!hdev->hiddev_connect(hdev,
+				connect_mask & HID_CONNECT_HIDDEV_FORCE))
+		hdev->claimed |= HID_CLAIMED_HIDDEV;
+	if ((connect_mask & HID_CONNECT_HIDRAW) && !hidraw_connect(hdev))
+		hdev->claimed |= HID_CLAIMED_HIDRAW;
+
+	if (connect_mask & HID_CONNECT_DRIVER)
+		hdev->claimed |= HID_CLAIMED_DRIVER;
+
+	/* Drivers with the ->raw_event callback set are not required to connect
+	 * to any other listener. */
+	if (!hdev->claimed && !hdev->driver->raw_event) {
+		hid_err(hdev, "device has no listeners, quitting\n");
+		return -ENODEV;
+	}
+
+	if ((hdev->claimed & HID_CLAIMED_INPUT) &&
+			(connect_mask & HID_CONNECT_FF) && hdev->ff_init)
+		hdev->ff_init(hdev);
+
+	len = 0;
+	if (hdev->claimed & HID_CLAIMED_INPUT)
+		len += sprintf(buf + len, "input");
+	if (hdev->claimed & HID_CLAIMED_HIDDEV)
+		len += sprintf(buf + len, "%shiddev%d", len ? "," : "",
+				((struct hiddev *)hdev->hiddev)->minor);
+	if (hdev->claimed & HID_CLAIMED_HIDRAW)
+		len += sprintf(buf + len, "%shidraw%d", len ? "," : "",
+				((struct hidraw *)hdev->hidraw)->minor);
+
+	type = "Device";
+	for (i = 0; i < hdev->maxcollection; i++) {
+		struct hid_collection *col = &hdev->collection[i];
+		if (col->type == HID_COLLECTION_APPLICATION &&
+		   (col->usage & HID_USAGE_PAGE) == HID_UP_GENDESK &&
+		   (col->usage & 0xffff) < ARRAY_SIZE(types)) {
+			type = types[col->usage & 0xffff];
+			break;
+		}
+	}
+
+	switch (hdev->bus) {
+	case BUS_USB:
+		bus = "USB";
+		break;
+	case BUS_BLUETOOTH:
+		bus = "BLUETOOTH";
+		break;
+	case BUS_I2C:
+		bus = "I2C";
+		break;
+	case BUS_VIRTUAL:
+		bus = "VIRTUAL";
+		break;
+	default:
+		bus = "<UNKNOWN>";
+	}
+
+	ret = device_create_file(&hdev->dev, &dev_attr_country);
+	if (ret)
+		hid_warn(hdev,
+			 "can't create sysfs country code attribute err: %d\n", ret);
+
+	hid_info(hdev, "%s: %s HID v%x.%02x %s [%s] on %s\n",
+		 buf, bus, hdev->version >> 8, hdev->version & 0xff,
+		 type, hdev->name, hdev->phys);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(hid_connect);
+
+void hid_disconnect(struct hid_device *hdev)
+{
+	device_remove_file(&hdev->dev, &dev_attr_country);
+	if (hdev->claimed & HID_CLAIMED_INPUT)
+		hidinput_disconnect(hdev);
+	if (hdev->claimed & HID_CLAIMED_HIDDEV)
+		hdev->hiddev_disconnect(hdev);
+	if (hdev->claimed & HID_CLAIMED_HIDRAW)
+		hidraw_disconnect(hdev);
+	hdev->claimed = 0;
+}
+EXPORT_SYMBOL_GPL(hid_disconnect);
+
+/**
+ * hid_hw_start - start underlying HW
+ * @hdev: hid device
+ * @connect_mask: which outputs to connect, see HID_CONNECT_*
+ *
+ * Call this in probe function *after* hid_parse. This will setup HW
+ * buffers and start the device (if not defeirred to device open).
+ * hid_hw_stop must be called if this was successful.
+ */
+int hid_hw_start(struct hid_device *hdev, unsigned int connect_mask)
+{
+	int error;
+
+	error = hdev->ll_driver->start(hdev);
+	if (error)
+		return error;
+
+	if (connect_mask) {
+		error = hid_connect(hdev, connect_mask);
+		if (error) {
+			hdev->ll_driver->stop(hdev);
+			return error;
+		}
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(hid_hw_start);
+
+/**
+ * hid_hw_stop - stop underlying HW
+ * @hdev: hid device
+ *
+ * This is usually called from remove function or from probe when something
+ * failed and hid_hw_start was called already.
+ */
+void hid_hw_stop(struct hid_device *hdev)
+{
+	hid_disconnect(hdev);
+	hdev->ll_driver->stop(hdev);
+}
+EXPORT_SYMBOL_GPL(hid_hw_stop);
+
+/**
+ * hid_hw_open - signal underlying HW to start delivering events
+ * @hdev: hid device
+ *
+ * Tell underlying HW to start delivering events from the device.
+ * This function should be called sometime after successful call
+ * to hid_hw_start().
+ */
+int hid_hw_open(struct hid_device *hdev)
+{
+	int ret;
+
+	ret = mutex_lock_killable(&hdev->ll_open_lock);
+	if (ret)
+		return ret;
+
+	if (!hdev->ll_open_count++) {
+		ret = hdev->ll_driver->open(hdev);
+		if (ret)
+			hdev->ll_open_count--;
+	}
+
+	mutex_unlock(&hdev->ll_open_lock);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(hid_hw_open);
+
+/**
+ * hid_hw_close - signal underlaying HW to stop delivering events
+ *
+ * @hdev: hid device
+ *
+ * This function indicates that we are not interested in the events
+ * from this device anymore. Delivery of events may or may not stop,
+ * depending on the number of users still outstanding.
+ */
+void hid_hw_close(struct hid_device *hdev)
+{
+	mutex_lock(&hdev->ll_open_lock);
+	if (!--hdev->ll_open_count)
+		hdev->ll_driver->close(hdev);
+	mutex_unlock(&hdev->ll_open_lock);
+}
+EXPORT_SYMBOL_GPL(hid_hw_close);
+
+struct hid_dynid {
+	struct list_head list;
+	struct hid_device_id id;
+};
+
+/**
+ * store_new_id - add a new HID device ID to this driver and re-probe devices
+ * @drv: target device driver
+ * @buf: buffer for scanning device ID data
+ * @count: input size
+ *
+ * Adds a new dynamic hid device ID to this driver,
+ * and causes the driver to probe for all devices again.
+ */
+static ssize_t new_id_store(struct device_driver *drv, const char *buf,
+		size_t count)
+{
+	struct hid_driver *hdrv = to_hid_driver(drv);
+	struct hid_dynid *dynid;
+	__u32 bus, vendor, product;
+	unsigned long driver_data = 0;
+	int ret;
+
+	ret = sscanf(buf, "%x %x %x %lx",
+			&bus, &vendor, &product, &driver_data);
+	if (ret < 3)
+		return -EINVAL;
+
+	dynid = kzalloc(sizeof(*dynid), GFP_KERNEL);
+	if (!dynid)
+		return -ENOMEM;
+
+	dynid->id.bus = bus;
+	dynid->id.group = HID_GROUP_ANY;
+	dynid->id.vendor = vendor;
+	dynid->id.product = product;
+	dynid->id.driver_data = driver_data;
+
+	spin_lock(&hdrv->dyn_lock);
+	list_add_tail(&dynid->list, &hdrv->dyn_list);
+	spin_unlock(&hdrv->dyn_lock);
+
+	ret = driver_attach(&hdrv->driver);
+
+	return ret ? : count;
+}
+static DRIVER_ATTR_WO(new_id);
+
+static struct attribute *hid_drv_attrs[] = {
+	&driver_attr_new_id.attr,
+	NULL,
+};
+ATTRIBUTE_GROUPS(hid_drv);
+
+static void hid_free_dynids(struct hid_driver *hdrv)
+{
+	struct hid_dynid *dynid, *n;
+
+	spin_lock(&hdrv->dyn_lock);
+	list_for_each_entry_safe(dynid, n, &hdrv->dyn_list, list) {
+		list_del(&dynid->list);
+		kfree(dynid);
+	}
+	spin_unlock(&hdrv->dyn_lock);
+}
+
+const struct hid_device_id *hid_match_device(struct hid_device *hdev,
+					     struct hid_driver *hdrv)
+{
+	struct hid_dynid *dynid;
+
+	spin_lock(&hdrv->dyn_lock);
+	list_for_each_entry(dynid, &hdrv->dyn_list, list) {
+		if (hid_match_one_id(hdev, &dynid->id)) {
+			spin_unlock(&hdrv->dyn_lock);
+			return &dynid->id;
+		}
+	}
+	spin_unlock(&hdrv->dyn_lock);
+
+	return hid_match_id(hdev, hdrv->id_table);
+}
+EXPORT_SYMBOL_GPL(hid_match_device);
+
+static int hid_bus_match(struct device *dev, struct device_driver *drv)
+{
+	struct hid_driver *hdrv = to_hid_driver(drv);
+	struct hid_device *hdev = to_hid_device(dev);
+
+	return hid_match_device(hdev, hdrv) != NULL;
+}
+
+/**
+ * hid_compare_device_paths - check if both devices share the same path
+ * @hdev_a: hid device
+ * @hdev_b: hid device
+ * @separator: char to use as separator
+ *
+ * Check if two devices share the same path up to the last occurrence of
+ * the separator char. Both paths must exist (i.e., zero-length paths
+ * don't match).
+ */
+bool hid_compare_device_paths(struct hid_device *hdev_a,
+			      struct hid_device *hdev_b, char separator)
+{
+	int n1 = strrchr(hdev_a->phys, separator) - hdev_a->phys;
+	int n2 = strrchr(hdev_b->phys, separator) - hdev_b->phys;
+
+	if (n1 != n2 || n1 <= 0 || n2 <= 0)
+		return false;
+
+	return !strncmp(hdev_a->phys, hdev_b->phys, n1);
+}
+EXPORT_SYMBOL_GPL(hid_compare_device_paths);
+
+static int hid_device_probe(struct device *dev)
+{
+	struct hid_driver *hdrv = to_hid_driver(dev->driver);
+	struct hid_device *hdev = to_hid_device(dev);
+	const struct hid_device_id *id;
+	int ret = 0;
+
+	if (down_interruptible(&hdev->driver_input_lock)) {
+		ret = -EINTR;
+		goto end;
+	}
+	hdev->io_started = false;
+
+	clear_bit(ffs(HID_STAT_REPROBED), &hdev->status);
+
+	if (!hdev->driver) {
+		id = hid_match_device(hdev, hdrv);
+		if (id == NULL) {
+			ret = -ENODEV;
+			goto unlock;
+		}
+
+		if (hdrv->match) {
+			if (!hdrv->match(hdev, hid_ignore_special_drivers)) {
+				ret = -ENODEV;
+				goto unlock;
+			}
+		} else {
+			/*
+			 * hid-generic implements .match(), so if
+			 * hid_ignore_special_drivers is set, we can safely
+			 * return.
+			 */
+			if (hid_ignore_special_drivers) {
+				ret = -ENODEV;
+				goto unlock;
+			}
+		}
+
+		/* reset the quirks that has been previously set */
+		hdev->quirks = hid_lookup_quirk(hdev);
+		hdev->driver = hdrv;
+		if (hdrv->probe) {
+			ret = hdrv->probe(hdev, id);
+		} else { /* default probe */
+			ret = hid_open_report(hdev);
+			if (!ret)
+				ret = hid_hw_start(hdev, HID_CONNECT_DEFAULT);
+		}
+		if (ret) {
+			hid_close_report(hdev);
+			hdev->driver = NULL;
+		}
+	}
+unlock:
+	if (!hdev->io_started)
+		up(&hdev->driver_input_lock);
+end:
+	return ret;
+}
+
+static int hid_device_remove(struct device *dev)
+{
+	struct hid_device *hdev = to_hid_device(dev);
+	struct hid_driver *hdrv;
+
+	down(&hdev->driver_input_lock);
+	hdev->io_started = false;
+
+	hdrv = hdev->driver;
+	if (hdrv) {
+		if (hdrv->remove)
+			hdrv->remove(hdev);
+		else /* default remove */
+			hid_hw_stop(hdev);
+		hid_close_report(hdev);
+		hdev->driver = NULL;
+	}
+
+	if (!hdev->io_started)
+		up(&hdev->driver_input_lock);
+
+	return 0;
+}
+
+static ssize_t modalias_show(struct device *dev, struct device_attribute *a,
+			     char *buf)
+{
+	struct hid_device *hdev = container_of(dev, struct hid_device, dev);
+
+	return scnprintf(buf, PAGE_SIZE, "hid:b%04Xg%04Xv%08Xp%08X\n",
+			 hdev->bus, hdev->group, hdev->vendor, hdev->product);
+}
+static DEVICE_ATTR_RO(modalias);
+
+static struct attribute *hid_dev_attrs[] = {
+	&dev_attr_modalias.attr,
+	NULL,
+};
+static struct bin_attribute *hid_dev_bin_attrs[] = {
+	&dev_bin_attr_report_desc,
+	NULL
+};
+static const struct attribute_group hid_dev_group = {
+	.attrs = hid_dev_attrs,
+	.bin_attrs = hid_dev_bin_attrs,
+};
+__ATTRIBUTE_GROUPS(hid_dev);
+
+static int hid_uevent(struct device *dev, struct kobj_uevent_env *env)
+{
+	struct hid_device *hdev = to_hid_device(dev);
+
+	if (add_uevent_var(env, "HID_ID=%04X:%08X:%08X",
+			hdev->bus, hdev->vendor, hdev->product))
+		return -ENOMEM;
+
+	if (add_uevent_var(env, "HID_NAME=%s", hdev->name))
+		return -ENOMEM;
+
+	if (add_uevent_var(env, "HID_PHYS=%s", hdev->phys))
+		return -ENOMEM;
+
+	if (add_uevent_var(env, "HID_UNIQ=%s", hdev->uniq))
+		return -ENOMEM;
+
+	if (add_uevent_var(env, "MODALIAS=hid:b%04Xg%04Xv%08Xp%08X",
+			   hdev->bus, hdev->group, hdev->vendor, hdev->product))
+		return -ENOMEM;
+
+	return 0;
+}
+
+struct bus_type hid_bus_type = {
+	.name		= "hid",
+	.dev_groups	= hid_dev_groups,
+	.drv_groups	= hid_drv_groups,
+	.match		= hid_bus_match,
+	.probe		= hid_device_probe,
+	.remove		= hid_device_remove,
+	.uevent		= hid_uevent,
+};
+EXPORT_SYMBOL(hid_bus_type);
+
+int hid_add_device(struct hid_device *hdev)
+{
+	static atomic_t id = ATOMIC_INIT(0);
+	int ret;
+
+	if (WARN_ON(hdev->status & HID_STAT_ADDED))
+		return -EBUSY;
+
+	hdev->quirks = hid_lookup_quirk(hdev);
+
+	/* we need to kill them here, otherwise they will stay allocated to
+	 * wait for coming driver */
+	if (hid_ignore(hdev))
+		return -ENODEV;
+
+	/*
+	 * Check for the mandatory transport channel.
+	 */
+	 if (!hdev->ll_driver->raw_request) {
+		hid_err(hdev, "transport driver missing .raw_request()\n");
+		return -EINVAL;
+	 }
+
+	/*
+	 * Read the device report descriptor once and use as template
+	 * for the driver-specific modifications.
+	 */
+	ret = hdev->ll_driver->parse(hdev);
+	if (ret)
+		return ret;
+	if (!hdev->dev_rdesc)
+		return -ENODEV;
+
+	/*
+	 * Scan generic devices for group information
+	 */
+	if (hid_ignore_special_drivers) {
+		hdev->group = HID_GROUP_GENERIC;
+	} else if (!hdev->group &&
+		   !(hdev->quirks & HID_QUIRK_HAVE_SPECIAL_DRIVER)) {
+		ret = hid_scan_report(hdev);
+		if (ret)
+			hid_warn(hdev, "bad device descriptor (%d)\n", ret);
+	}
+
+	hdev->id = atomic_inc_return(&id);
+
+	/* XXX hack, any other cleaner solution after the driver core
+	 * is converted to allow more than 20 bytes as the device name? */
+	dev_set_name(&hdev->dev, "%04X:%04X:%04X.%04X", hdev->bus,
+		     hdev->vendor, hdev->product, hdev->id);
+
+	hid_debug_register(hdev, dev_name(&hdev->dev));
+	ret = device_add(&hdev->dev);
+	if (!ret)
+		hdev->status |= HID_STAT_ADDED;
+	else
+		hid_debug_unregister(hdev);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(hid_add_device);
+
+/**
+ * hid_allocate_device - allocate new hid device descriptor
+ *
+ * Allocate and initialize hid device, so that hid_destroy_device might be
+ * used to free it.
+ *
+ * New hid_device pointer is returned on success, otherwise ERR_PTR encoded
+ * error value.
+ */
+struct hid_device *hid_allocate_device(void)
+{
+	struct hid_device *hdev;
+	int ret = -ENOMEM;
+
+	hdev = kzalloc(sizeof(*hdev), GFP_KERNEL);
+	if (hdev == NULL)
+		return ERR_PTR(ret);
+
+	device_initialize(&hdev->dev);
+	hdev->dev.release = hid_device_release;
+	hdev->dev.bus = &hid_bus_type;
+	device_enable_async_suspend(&hdev->dev);
+
+	hid_close_report(hdev);
+
+	init_waitqueue_head(&hdev->debug_wait);
+	INIT_LIST_HEAD(&hdev->debug_list);
+	spin_lock_init(&hdev->debug_list_lock);
+	sema_init(&hdev->driver_input_lock, 1);
+	mutex_init(&hdev->ll_open_lock);
+	kref_init(&hdev->ref);
+
+	return hdev;
+}
+EXPORT_SYMBOL_GPL(hid_allocate_device);
+
+static void hid_remove_device(struct hid_device *hdev)
+{
+	if (hdev->status & HID_STAT_ADDED) {
+		device_del(&hdev->dev);
+		hid_debug_unregister(hdev);
+		hdev->status &= ~HID_STAT_ADDED;
+	}
+	kfree(hdev->dev_rdesc);
+	hdev->dev_rdesc = NULL;
+	hdev->dev_rsize = 0;
+}
+
+/**
+ * hid_destroy_device - free previously allocated device
+ *
+ * @hdev: hid device
+ *
+ * If you allocate hid_device through hid_allocate_device, you should ever
+ * free by this function.
+ */
+void hid_destroy_device(struct hid_device *hdev)
+{
+	hid_remove_device(hdev);
+	put_device(&hdev->dev);
+}
+EXPORT_SYMBOL_GPL(hid_destroy_device);
+
+
+static int __hid_bus_reprobe_drivers(struct device *dev, void *data)
+{
+	struct hid_driver *hdrv = data;
+	struct hid_device *hdev = to_hid_device(dev);
+
+	if (hdev->driver == hdrv &&
+	    !hdrv->match(hdev, hid_ignore_special_drivers) &&
+	    !test_and_set_bit(ffs(HID_STAT_REPROBED), &hdev->status))
+		return device_reprobe(dev);
+
+	return 0;
+}
+
+static int __hid_bus_driver_added(struct device_driver *drv, void *data)
+{
+	struct hid_driver *hdrv = to_hid_driver(drv);
+
+	if (hdrv->match) {
+		bus_for_each_dev(&hid_bus_type, NULL, hdrv,
+				 __hid_bus_reprobe_drivers);
+	}
+
+	return 0;
+}
+
+static int __bus_removed_driver(struct device_driver *drv, void *data)
+{
+	return bus_rescan_devices(&hid_bus_type);
+}
+
+int __hid_register_driver(struct hid_driver *hdrv, struct module *owner,
+		const char *mod_name)
+{
+	int ret;
+
+	hdrv->driver.name = hdrv->name;
+	hdrv->driver.bus = &hid_bus_type;
+	hdrv->driver.owner = owner;
+	hdrv->driver.mod_name = mod_name;
+
+	INIT_LIST_HEAD(&hdrv->dyn_list);
+	spin_lock_init(&hdrv->dyn_lock);
+
+	ret = driver_register(&hdrv->driver);
+
+	if (ret == 0)
+		bus_for_each_drv(&hid_bus_type, NULL, NULL,
+				 __hid_bus_driver_added);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(__hid_register_driver);
+
+void hid_unregister_driver(struct hid_driver *hdrv)
+{
+	driver_unregister(&hdrv->driver);
+	hid_free_dynids(hdrv);
+
+	bus_for_each_drv(&hid_bus_type, NULL, hdrv, __bus_removed_driver);
+}
+EXPORT_SYMBOL_GPL(hid_unregister_driver);
+
+int hid_check_keys_pressed(struct hid_device *hid)
+{
+	struct hid_input *hidinput;
+	int i;
+
+	if (!(hid->claimed & HID_CLAIMED_INPUT))
+		return 0;
+
+	list_for_each_entry(hidinput, &hid->inputs, list) {
+		for (i = 0; i < BITS_TO_LONGS(KEY_MAX); i++)
+			if (hidinput->input->key[i])
+				return 1;
+	}
+
+	return 0;
+}
+
+EXPORT_SYMBOL_GPL(hid_check_keys_pressed);
+
+static int __init hid_init(void)
+{
+	int ret;
+
+	if (hid_debug)
+		pr_warn("hid_debug is now used solely for parser and driver debugging.\n"
+			"debugfs is now used for inspecting the device (report descriptor, reports)\n");
+
+	ret = bus_register(&hid_bus_type);
+	if (ret) {
+		pr_err("can't register hid bus\n");
+		goto err;
+	}
+
+	ret = hidraw_init();
+	if (ret)
+		goto err_bus;
+
+	hid_debug_init();
+
+	return 0;
+err_bus:
+	bus_unregister(&hid_bus_type);
+err:
+	return ret;
+}
+
+static void __exit hid_exit(void)
+{
+	hid_debug_exit();
+	hidraw_exit();
+	bus_unregister(&hid_bus_type);
+	hid_quirks_exit(HID_BUS_ANY);
+}
+
+module_init(hid_init);
+module_exit(hid_exit);
+
+MODULE_AUTHOR("Andreas Gal");
+MODULE_AUTHOR("Vojtech Pavlik");
+MODULE_AUTHOR("Jiri Kosina");
+MODULE_LICENSE("GPL");