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Commit 1cf0c6e6 authored by Henrik Rydberg's avatar Henrik Rydberg
Browse files

Input: Add EVIOC mechanism for MT slots 



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: default avatarChase Douglas <chase.douglas@canonical.com>
Signed-off-by: default avatarHenrik Rydberg <rydberg@euromail.se>
parent b89529a1

drivers/input/evdev.c

+26 −1
Original line number Diff line number Diff line
@@ -20,7 +20,7 @@ 
#include <linux/slab.h>

#include <linux/module.h>

#include <linux/init.h>

#include <linux/input.h>

#include <linux/input/mt.h>

#include <linux/major.h>

#include <linux/device.h>

#include "input-compat.h"
@@ -623,6 +623,28 @@ static int evdev_handle_set_keycode_v2(struct input_dev *dev, void __user *p) 
	return input_set_keycode(dev, &ke);

}



static int evdev_handle_mt_request(struct input_dev *dev,

				   unsigned int size,

				   int __user *ip)

{

	const struct input_mt_slot *mt = dev->mt;

	unsigned int code;

	int max_slots;

	int i;



	if (get_user(code, &ip[0]))

		return -EFAULT;

	if (!input_is_mt_value(code))

		return -EINVAL;



	max_slots = (size - sizeof(__u32)) / sizeof(__s32);

	for (i = 0; i < dev->mtsize && i < max_slots; i++)

		if (put_user(input_mt_get_value(&mt[i], code), &ip[1 + i]))

			return -EFAULT;



	return 0;

}



static long evdev_do_ioctl(struct file *file, unsigned int cmd,

			   void __user *p, int compat_mode)

{
@@ -708,6 +730,9 @@ static long evdev_do_ioctl(struct file *file, unsigned int cmd, 
		return bits_to_user(dev->propbit, INPUT_PROP_MAX,

				    size, p, compat_mode);



	case EVIOCGMTSLOTS(0):

		return evdev_handle_mt_request(dev, size, ip);



	case EVIOCGKEY(0):

		return bits_to_user(dev->key, KEY_MAX, size, p, compat_mode);

include/linux/input.h

+25 −0
Original line number Diff line number Diff line
@@ -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 */