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 INPUT_MT_REQUEST(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]);
Signed-off-by: Henrik Rydberg <rydberg@xxxxxxxxxxx>
---
Hi Dmitry,
Here is v3 of the EVIOC patch for MT slots. The number of slots if
gone, the struct is simplified, targeting userland, and calling the
ioctl with a smaller struct will return the first set of slots.
Cheers,
Henrik
drivers/input/evdev.c | 27 ++++++++++++++++++++++++++-
include/linux/input.h | 23 +++++++++++++++++++++++
2 files changed, 49 insertions(+), 1 deletions(-)
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 @@ 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);
diff --git a/include/linux/input.h b/include/linux/input.h
index 3862e32..1e7e2e5 100644
--- a/include/linux/input.h
+++ b/include/linux/input.h
@@ -99,6 +99,28 @@ struct input_keymap_entry {
__u8 scancode[32];
};
+/**
+ * struct INPUT_MT_REQUEST(num_slots) - used by EVIOCGMTSLOTS ioctl
+ * @code: ABS_MT code to read
+ * @values: value array, one value per slot
+ *
+ * The struct definition is used to create an appropriate MT slot message
+ * buffer in userland. Before the call, code is set to the wanted ABS_MT
+ * event type. On return, the value array is filled with the slot values
+ * for the specified ABS_MT code.
+ *
+ * The call argument (len) is the size of the return buffer, which should
+ * satisfy len >= sizeof(struct INPUT_MT_REQUEST(num_slots)). If len is
+ * too small to fit all available slots, the first num_slots are returned.
+ *
+ * If the request code is not an ABS_MT value, -EINVAL is returned.
+ */
+#define INPUT_MT_REQUEST(num_slots) \
+ { \
+ __u32 code; \
+ __s32 values[num_slots]; \
+ }
+
#define EVIOCGVERSION _IOR('E', 0x01, int) /* get driver version */
#define EVIOCGID _IOR('E', 0x02, struct input_id) /* get device ID */
#define EVIOCGREP _IOR('E', 0x03, unsigned int[2]) /* get repeat settings */
@@ -113,6 +135,7 @@ struct input_keymap_entry {
#define EVIOCGPHYS(len) _IOC(_IOC_READ, 'E', 0x07, len) /* get physical location */
#define EVIOCGUNIQ(len) _IOC(_IOC_READ, 'E', 0x08, len) /* get unique identifier */
#define EVIOCGPROP(len) _IOC(_IOC_READ, 'E', 0x09, len) /* get device properties */
+#define EVIOCGMTSLOTS(len) _IOC(_IOC_READ, 'E', 0x0a, len) /* get MT slot values */
#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 */
--
1.7.9
--
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