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Input: Add EVIOC mechanism for MT slots

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This patch adds the ability to extract MT slot data via a new ioctl,
EVIOCGMTSLOTS. The function returns an array of slot values for the
specified ABS_MT event type.

Example of user space usage:

struct { unsigned code; int values[64]; } req;
req.code = ABS_MT_POSITION_X;
if (ioctl(fd, EVIOCGMTSLOTS(sizeof(req)), &req) < 0)
	return -1;
for (i = 0; i < 64; i++)
	printf("slot %d: %d\n", i, req.values[i]);

Reviewed-by: Chase Douglas <chase.douglas@canonical.com>
Signed-off-by: Henrik Rydberg <rydberg@euromail.se>
This commit is contained in:
Henrik Rydberg
2012-02-06 08:49:25 +01:00
parent b89529a10c
commit 1cf0c6e69e
2 changed files with 51 additions and 1 deletions
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25
include/linux/input.h
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@ -114,6 +114,31 @@ struct input_keymap_entry {
#define EVIOCGUNIQ(len) _IOC(_IOC_READ, 'E', 0x08, len) /* get unique identifier */
#define EVIOCGPROP(len) _IOC(_IOC_READ, 'E', 0x09, len) /* get device properties */
/**
* EVIOCGMTSLOTS(len) - get MT slot values
*
* The ioctl buffer argument should be binary equivalent to
*
* struct input_mt_request_layout {
* __u32 code;
* __s32 values[num_slots];
* };
*
* where num_slots is the (arbitrary) number of MT slots to extract.
*
* The ioctl size argument (len) is the size of the buffer, which
* should satisfy len = (num_slots + 1) * sizeof(__s32). If len is
* too small to fit all available slots, the first num_slots are
* returned.
*
* Before the call, code is set to the wanted ABS_MT event type. On
* return, values[] is filled with the slot values for the specified
* ABS_MT code.
*
* If the request code is not an ABS_MT value, -EINVAL is returned.
*/
#define EVIOCGMTSLOTS(len) _IOC(_IOC_READ, 'E', 0x0a, len)
#define EVIOCGKEY(len) _IOC(_IOC_READ, 'E', 0x18, len) /* get global key state */
#define EVIOCGLED(len) _IOC(_IOC_READ, 'E', 0x19, len) /* get all LEDs */
#define EVIOCGSND(len) _IOC(_IOC_READ, 'E', 0x1a, len) /* get all sounds status */