USBHID(3) | Library Functions Manual | USBHID(3) |
usbhid
, hid_get_report_desc
,
hid_use_report_desc
,
hid_dispose_report_desc
,
hid_start_parse
,
hid_end_parse
, hid_get_item
,
hid_report_size
, hid_locate
,
hid_usage_page
,
hid_usage_in_page
,
hid_parse_usage_page
,
hid_parse_usage_in_page
,
hid_init
, hid_get_data
,
hid_set_data
—
#include <usbhid.h>
report_desc_t
hid_get_report_desc
(int
file);
report_desc_t
hid_use_report_desc
(const
uint8_t *data, unsigned
int size);
void
hid_dispose_report_desc
(report_desc_t
d);
hid_data_t
hid_start_parse
(report_desc_t
d, int kindset,
int id);
void
hid_end_parse
(hid_data_t
s);
int
hid_get_item
(hid_data_t
s, hid_item_t
*h);
int
hid_report_size
(report_desc_t
d, hid_kind_t k,
int id);
int
hid_locate
(report_desc_t
d, u_int usage,
hid_kind_t k,
hid_item_t *h,
int id);
char *
hid_usage_page
(int
i);
char *
hid_usage_in_page
(u_int
u);
int
hid_parse_usage_page
(const
char *);
char *
hid_parse_usage_in_page
(const
char *);
void
hid_init
(const
char *file);
int
hid_get_data
(const
void *data, const
hid_item_t *h);
void
hid_set_data
(void
*data, const hid_item_t
*h, u_int
data);
usbhid
library provides routines to extract data
from USB Human Interface Devices.
usbhid
library contains routines to extract the
report descriptor which contains the data layout information
and then use this information.
The routines can be divided into four parts: extraction of the descriptor, parsing of the descriptor, translating to/from symbolic names, and data manipulation.
hid_get_report_desc
() with a file descriptor obtained
by opening a uhid(4) device.
Alternatively a data buffer containing the report descriptor can be passed
into hid_use_report_desc
(). The data is copied into an
internal structure. When the report descriptor is no longer needed it should
be freed by calling hid_dispose_report_desc
(). The
type report_desc_t is opaque and should be used when
calling the parsing functions. If
hid_dispose_report_desc
() fails it will return
NULL.
hid_start_parse
()
function should be called with a report descriptor and a set that describes
which items that are interesting. The set is obtained by or-ing together
values (1 << k) where k is
an item of type hid_kind_t. The report ID (if present)
is given by id. The function returns
NULL if the initialization fails, otherwise an opaque
value to be used in subsequent calls. After parsing the
hid_end_parse
() function should be called to free
internal data structures.
To iterate through all the items in the report descriptor,
hid_get_item
() should be called while it returns a
value greater than 0. When the report descriptor ends it will return 0; a
syntax error within the report descriptor will cause a return value less
than 0. The struct pointed to by h will be filled with
the relevant data for the item. The definition of
hid_item_t can be found in
<usbhid.h>
and the meaning
of the components in the USB HID documentation.
Data should be read/written to the device in the size of the
report. The size of a report (of a certain kind) can be computed by the
hid_report_size
() function. If the report is
prefixed by an ID byte it is given by id.
To locate a single item the hid_locate
()
function can be used. It should be given the usage code of the item and its
kind and it will fill the item and return non-zero if the item was
found.
hid_usage_page
() will return the symbolic
name of a usage page, and the function
hid_usage_in_page
() will return the symbolic name of
the usage within the page. Both these functions may return a pointer to static
data.
The functions hid_parse_usage_page
() and
hid_parse_usage_in_page
() are the inverses of
hid_usage_page
() and
hid_usage_in_page
(). They take a usage string and
return the number of the usage, or -1 if it cannot be found.
Before any of these functions can be called the usage table must
be parsed, this is done by calling hid_init
() with
the name of the table. Passing NULL to this function
will cause it to use the default table.
hid_get_data
() function extracts the value of the
item. Conversely hid_set_data
() can be used to put
data into a report (which must be zeroed first).
usbhid
library first appeared in
NetBSD 1.5 as usb
library and
was renamed to usbhid
for NetBSD
1.6.
May 12, 2010 | NetBSD 9.2 |