[v3,1/7] Input: add input_device_enabled()

Commit Message

Andrzej Pietrasiewicz June 5, 2020, 5:33 p.m. UTC

A helper function for drivers to decide if the device is used or not.
A lockdep check is introduced as inspecting ->users should be done under
input device's mutex.

Signed-off-by: Andrzej Pietrasiewicz <[e-mail]>
---
 drivers/input/input.c | 8 ++++++++
 include/linux/input.h | 2 ++
 2 files changed, 10 insertions(+)

Patch

diff --git a/drivers/input/input.c b/drivers/input/input.c
index 3cfd2c18eebd..41377bfa142d 100644
--- a/drivers/input/input.c
+++ b/drivers/input/input.c
@@ -2127,6 +2127,14 @@  void input_enable_softrepeat(struct input_dev *dev, int delay, int period)
 }
 EXPORT_SYMBOL(input_enable_softrepeat);
 
+bool input_device_enabled(struct input_dev *dev)
+{
+	lockdep_assert_held(&dev->mutex);
+
+	return dev->users > 0;
+}
+EXPORT_SYMBOL_GPL(input_device_enabled);
+
 /**
  * input_register_device - register device with input core
  * @dev: device to be registered
diff --git a/include/linux/input.h b/include/linux/input.h
index 56f2fd32e609..eda4587dba67 100644
--- a/include/linux/input.h
+++ b/include/linux/input.h
@@ -502,6 +502,8 @@  bool input_match_device_id(const struct input_dev *dev,
 
 void input_enable_softrepeat(struct input_dev *dev, int delay, int period);
 
+bool input_device_enabled(struct input_dev *dev);
+
 extern struct class input_class;
 
 /**