Input: allow drivers specify timestamp for input events

Currently, evdev stamps events with timestamps acquired in evdev_events()
However, this timestamping may not be accurate in terms of measuring
when the actual event happened.

Let's allow individual drivers specify timestamp in order to provide a more
accurate sense of time for the event. It is expected that drivers will set the
timestamp in their hard interrupt routine.

Signed-off-by: Atif Niyaz <atifniyaz@google.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

1 files changed, 14 insertions, 0 deletions

diff --git a/include/linux/input.h b/include/linux/input.h
index 510e78558c10..e95a439d8bd5 100644
--- a/include/linux/input.h
+++ b/include/linux/input.h
@@ -33,6 +33,13 @@ struct input_value {
 	__s32 value;
 };
 
+enum input_clock_type {
+	INPUT_CLK_REAL = 0,
+	INPUT_CLK_MONO,
+	INPUT_CLK_BOOT,
+	INPUT_CLK_MAX
+};
+
 /**
  * struct input_dev - represents an input device
  * @name: name of the device
@@ -114,6 +121,8 @@ struct input_value {
  * @vals: array of values queued in the current frame
  * @devres_managed: indicates that devices is managed with devres framework
  *	and needs not be explicitly unregistered or freed.
+ * @timestamp: storage for a timestamp set by input_set_timestamp called
+ *  by a driver
  */
 struct input_dev {
 	const char *name;
@@ -184,6 +193,8 @@ struct input_dev {
 	struct input_value *vals;
 
 	bool devres_managed;
+
+	ktime_t timestamp[INPUT_CLK_MAX];
 };
 #define to_input_dev(d) container_of(d, struct input_dev, dev)
 
@@ -382,6 +393,9 @@ void input_close_device(struct input_handle *);
 
 int input_flush_device(struct input_handle *handle, struct file *file);
 
+void input_set_timestamp(struct input_dev *dev, ktime_t timestamp);
+ktime_t *input_get_timestamp(struct input_dev *dev);
+
 void input_event(struct input_dev *dev, unsigned int type, unsigned int code, int value);
 void input_inject_event(struct input_handle *handle, unsigned int type, unsigned int code, int value);