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: Chase Douglas <chase.douglas@canonical.com>
Signed-off-by: Henrik Rydberg <rydberg@euromail.se>
diff --git a/drivers/input/evdev.c b/drivers/input/evdev.c
index 76457d5..e4cad16 100644
--- a/drivers/input/evdev.c
+++ b/drivers/input/evdev.c
@@ -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 @@
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 @@
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);
