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hid-core.c
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/*
* HID support for Linux
*
* Copyright (c) 1999 Andreas Gal
* Copyright (c) 2000-2005 Vojtech Pavlik <[email protected]>
* Copyright (c) 2005 Michael Haboustak <[email protected]> for Concept2, Inc
* Copyright (c) 2006-2007 Jiri Kosina
*/
/*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the Free
* Software Foundation; either version 2 of the License, or (at your option)
* any later version.
*/
#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/hid.h>
#include <linux/hiddev.h>
#include <linux/hid-debug.h>
#include <linux/hidraw.h>
#include "hid-ids.h"
/*
* Version Information
*/
#define DRIVER_VERSION "v2.6"
#define DRIVER_AUTHOR "Andreas Gal, Vojtech Pavlik, Jiri Kosina"
#define DRIVER_DESC "HID core driver"
#define DRIVER_LICENSE "GPL"
#ifdef CONFIG_HID_DEBUG
int hid_debug = 0;
module_param_named(debug, hid_debug, int, 0600);
MODULE_PARM_DESC(debug, "HID debugging (0=off, 1=probing info, 2=continuous data dumping)");
EXPORT_SYMBOL_GPL(hid_debug);
#endif
/*
* Register a new report for a device.
*/
static struct hid_report *hid_register_report(struct hid_device *device, unsigned type, unsigned id)
{
struct hid_report_enum *report_enum = device->report_enum + type;
struct hid_report *report;
if (report_enum->report_id_hash[id])
return report_enum->report_id_hash[id];
if (!(report = kzalloc(sizeof(struct hid_report), GFP_KERNEL)))
return NULL;
if (id != 0)
report_enum->numbered = 1;
report->id = id;
report->type = type;
report->size = 0;
report->device = device;
report_enum->report_id_hash[id] = report;
list_add_tail(&report->list, &report_enum->report_list);
return report;
}
/*
* Register a new field for this report.
*/
static struct hid_field *hid_register_field(struct hid_report *report, unsigned usages, unsigned values)
{
struct hid_field *field;
if (report->maxfield == HID_MAX_FIELDS) {
dbg_hid("too many fields in report\n");
return NULL;
}
if (!(field = kzalloc(sizeof(struct hid_field) + usages * sizeof(struct hid_usage)
+ values * sizeof(unsigned), GFP_KERNEL))) 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;
usage = parser->local.usage[0];
if (parser->collection_stack_ptr == HID_COLLECTION_STACK_SIZE) {
dbg_hid("collection stack overflow\n");
return -1;
}
if (parser->device->maxcollection == parser->device->collection_size) {
collection = kmalloc(sizeof(struct hid_collection) *
parser->device->collection_size * 2, GFP_KERNEL);
if (collection == NULL) {
dbg_hid("failed to reallocate collection array\n");
return -1;
}
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 = parser->device->collection +
parser->device->maxcollection++;
collection->type = type;
collection->usage = usage;
collection->level = parser->collection_stack_ptr - 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) {
dbg_hid("collection stack underflow\n");
return -1;
}
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)
{
int n;
for (n = parser->collection_stack_ptr - 1; n >= 0; n--)
if (parser->device->collection[parser->collection_stack[n]].type == type)
return parser->device->collection[parser->collection_stack[n]].usage;
return 0; /* we know nothing about this usage type */
}
/*
* Add a usage to the temporary parser table.
*/
static int hid_add_usage(struct hid_parser *parser, unsigned usage)
{
if (parser->local.usage_index >= HID_MAX_USAGES) {
dbg_hid("usage index exceeded\n");
return -1;
}
parser->local.usage[parser->local.usage_index] = usage;
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;
int usages;
unsigned offset;
int i;
if (!(report = hid_register_report(parser->device, report_type, parser->global.report_id))) {
dbg_hid("hid_register_report failed\n");
return -1;
}
if (parser->global.logical_maximum < parser->global.logical_minimum) {
dbg_hid("logical range invalid %d %d\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->local.usage_index) /* Ignore padding fields */
return 0;
usages = max_t(int, parser->local.usage_index, parser->global.report_count);
if ((field = hid_register_field(report, usages, parser->global.report_count)) == NULL)
return 0;
field->physical = hid_lookup_collection(parser, HID_COLLECTION_PHYSICAL);
field->logical = hid_lookup_collection(parser, HID_COLLECTION_LOGICAL);
field->application = hid_lookup_collection(parser, HID_COLLECTION_APPLICATION);
for (i = 0; i < usages; i++) {
int 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->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)
{
switch (item->tag) {
case HID_GLOBAL_ITEM_TAG_PUSH:
if (parser->global_stack_ptr == HID_GLOBAL_STACK_SIZE) {
dbg_hid("global enviroment 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) {
dbg_hid("global enviroment 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:
parser->global.unit_exponent = item_sdata(item);
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 > 32) {
dbg_hid("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) {
dbg_hid("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) {
dbg_hid("report_id 0 is invalid\n");
return -1;
}
return 0;
default:
dbg_hid("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;
if (item->size == 0) {
dbg_hid("item data expected for local item\n");
return -1;
}
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) {
dbg_hid("nested delimiters\n");
return -1;
}
parser->local.delimiter_depth++;
parser->local.delimiter_branch++;
} else {
if (parser->local.delimiter_depth < 1) {
dbg_hid("bogus close delimiter\n");
return -1;
}
parser->local.delimiter_depth--;
}
return 1;
case HID_LOCAL_ITEM_TAG_USAGE:
if (parser->local.delimiter_branch > 1) {
dbg_hid("alternative usage ignored\n");
return 0;
}
if (item->size <= 2)
data = (parser->global.usage_page << 16) + data;
return hid_add_usage(parser, data);
case HID_LOCAL_ITEM_TAG_USAGE_MINIMUM:
if (parser->local.delimiter_branch > 1) {
dbg_hid("alternative usage ignored\n");
return 0;
}
if (item->size <= 2)
data = (parser->global.usage_page << 16) + data;
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;
}
if (item->size <= 2)
data = (parser->global.usage_page << 16) + data;
for (n = parser->local.usage_minimum; n <= data; n++)
if (hid_add_usage(parser, n)) {
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;
}
/*
* Process a main item.
*/
static int hid_parser_main(struct hid_parser *parser, struct hid_item *item)
{
__u32 data;
int ret;
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:
dbg_hid("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);
}
/*
* Free a device structure, all reports, and all fields.
*/
static void hid_device_release(struct device *dev)
{
struct hid_device *device = container_of(dev, struct hid_device, dev);
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 < 256; j++) {
struct hid_report *report = report_enum->report_id_hash[j];
if (report)
hid_free_report(report);
}
}
kfree(device->rdesc);
kfree(device->collection);
kfree(device);
}
/*
* 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;
}
/**
* hid_parse_report - parse device report
*
* @device: hid device
* @start: report start
* @size: report size
*
* 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.
*/
int hid_parse_report(struct hid_device *device, __u8 *start,
unsigned size)
{
struct hid_parser *parser;
struct hid_item item;
__u8 *end;
int ret;
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 (device->driver->report_fixup)
device->driver->report_fixup(device, start, size);
device->rdesc = kmalloc(size, GFP_KERNEL);
if (device->rdesc == NULL)
return -ENOMEM;
memcpy(device->rdesc, start, size);
device->rsize = size;
parser = vmalloc(sizeof(struct hid_parser));
if (!parser) {
ret = -ENOMEM;
goto err;
}
memset(parser, 0, sizeof(struct hid_parser));
parser->device = device;
end = start + size;
ret = -EINVAL;
while ((start = fetch_item(start, end, &item)) != NULL) {
if (item.format != HID_ITEM_FORMAT_SHORT) {
dbg_hid("unexpected long global item\n");
goto err;
}
if (dispatch_type[item.type](parser, &item)) {
dbg_hid("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) {
dbg_hid("unbalanced collection at end of report description\n");
goto err;
}
if (parser->local.delimiter_depth) {
dbg_hid("unbalanced delimiter at end of report description\n");
goto err;
}
vfree(parser);
return 0;
}
}
dbg_hid("item fetching failed at offset %d\n", (int)(end - start));
err:
vfree(parser);
return ret;
}
EXPORT_SYMBOL_GPL(hid_parse_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)
{
switch (n) {
case 8: return ((__s8)value);
case 16: return ((__s16)value);
case 32: return ((__s32)value);
}
return value & (1 << (n - 1)) ? value | (-1 << n) : value;
}
/*
* 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/devclass_docs/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 __inline__ __u32 extract(__u8 *report, unsigned offset, unsigned n)
{
u64 x;
if (n > 32)
printk(KERN_WARNING "HID: extract() called with n (%d) > 32! (%s)\n",
n, current->comm);
report += offset >> 3; /* adjust byte index */
offset &= 7; /* now only need bit offset into one byte */
x = get_unaligned_le64(report);
x = (x >> offset) & ((1ULL << n) - 1); /* extract bit field */
return (u32) x;
}
/*
* "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 endiad bit stream.
*/
static __inline__ void implement(__u8 *report, unsigned offset, unsigned n, __u32 value)
{
u64 x;
u64 m = (1ULL << n) - 1;
if (n > 32)
printk(KERN_WARNING "HID: implement() called with n (%d) > 32! (%s)\n",
n, current->comm);
if (value > m)
printk(KERN_WARNING "HID: implement() called with too large value %d! (%s)\n",
value, current->comm);
WARN_ON(value > m);
value &= m;
report += offset >> 3;
offset &= 7;
x = get_unaligned_le64(report);
x &= ~(m << offset);
x |= ((u64)value) << offset;
put_unaligned_le64(x, report);
}
/*
* Search an array for a value.
*/
static __inline__ 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_type: type 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;
hid_dump_input(usage, value);
if (hdrv && hdrv->event && hid_match_usage(hid, usage)) {
ret = hdrv->event(hid, field, usage, value);
if (ret != 0) {
if (ret < 0)
dbg_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;
if (!(value = kmalloc(sizeof(__s32) * count, GFP_ATOMIC)))
return;
for (n = 0; n < count; n++) {
value[n] = min < 0 ? snto32(extract(data, offset + n * size, size), size) :
extract(data, offset + n * size, size);
if (!(field->flags & HID_MAIN_ITEM_VARIABLE) /* Ignore report if ErrorRollOver */
&& value[n] >= min && value[n] <= max
&& 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->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
&& 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(struct hid_field *field, __u8 *data)
{
unsigned count = field->report_count;
unsigned offset = field->report_offset;
unsigned size = field->report_size;
unsigned bitsused = offset + count * size;
unsigned n;
/* make sure the unused bits in the last byte are zeros */
if (count > 0 && size > 0 && (bitsused % 8) != 0)
data[(bitsused-1)/8] &= (1 << (bitsused % 8)) - 1;
for (n = 0; n < count; n++) {
if (field->logical_minimum < 0) /* signed values */
implement(data, offset + n * size, size, s32ton(field->value[n], size));
else /* unsigned values */
implement(data, offset + n * size, size, field->value[n]);
}
}
/*
* Create a report.
*/
void hid_output_report(struct hid_report *report, __u8 *data)
{
unsigned n;
if (report->id > 0)
*data++ = report->id;
for (n = 0; n < report->maxfield; n++)
hid_output_field(report->field[n], data);
}
EXPORT_SYMBOL_GPL(hid_output_report);
/*
* 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 = field->report_size;
hid_dump_input(field->usage + offset, value);
if (offset >= field->report_count) {
dbg_hid("offset (%d) exceeds report_count (%d)\n", offset, field->report_count);
hid_dump_field(field, 8);
return -1;
}
if (field->logical_minimum < 0) {
if (value != snto32(s32ton(value, size), size)) {
dbg_hid("value %d is out of range\n", value);
return -1;
}
}
field->value[offset] = value;
return 0;