From ba4e9a61ad54c438d4c7b655e94e31f23a6fe13f Mon Sep 17 00:00:00 2001
From: David Herrmann <dh.herrmann@gmail.com>
Date: Sun, 20 Jul 2014 17:27:09 -0700
Subject: [PATCH] Input: uinput - add UI_GET_VERSION ioctl

This ioctl is the counterpart to EVIOCGVERSION and returns the
uinput-version the kernel was compiled with.

Reviewed-by: Peter Hutterer <peter.hutterer@who-t.net>
Signed-off-by: David Herrmann <dh.herrmann@gmail.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
---
 drivers/input/misc/uinput.c | 6 ++++++
 include/uapi/linux/uinput.h | 9 +++++++++
 2 files changed, 15 insertions(+)

diff --git a/drivers/input/misc/uinput.c b/drivers/input/misc/uinput.c
index 883f045f37df..421e29e4cd81 100644
--- a/drivers/input/misc/uinput.c
+++ b/drivers/input/misc/uinput.c
@@ -723,6 +723,12 @@ static long uinput_ioctl_handler(struct file *file, unsigned int cmd,
 	}
 
 	switch (cmd) {
+		case UI_GET_VERSION:
+			if (put_user(UINPUT_VERSION,
+				     (unsigned int __user *)p))
+				retval = -EFAULT;
+			goto out;
+
 		case UI_DEV_CREATE:
 			retval = uinput_create_device(udev);
 			goto out;
diff --git a/include/uapi/linux/uinput.h b/include/uapi/linux/uinput.h
index 0389b489bbba..baeab83deb64 100644
--- a/include/uapi/linux/uinput.h
+++ b/include/uapi/linux/uinput.h
@@ -84,6 +84,15 @@ struct uinput_ff_erase {
  */
 #define UI_GET_SYSNAME(len)	_IOC(_IOC_READ, UINPUT_IOCTL_BASE, 300, len)
 
+/**
+ * UI_GET_VERSION - Return version of uinput protocol
+ *
+ * This writes uinput protocol version implemented by the kernel into
+ * the integer pointed to by the ioctl argument. The protocol version
+ * is hard-coded in the kernel and is independent of the uinput device.
+ */
+#define UI_GET_VERSION		_IOR(UINPUT_IOCTL_BASE, 301, unsigned int)
+
 /*
  * To write a force-feedback-capable driver, the upload_effect
  * and erase_effect callbacks in input_dev must be implemented.
-- 
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