Input: introduce managed input devices (add devres support)

There is a demand from driver's writers to use managed devices framework
for their drivers. Unfortunately up to this moment input devices did not
provide support for managed devices and that lead to mixing two styles
of resource management which usually introduced more bugs, such as
manually unregistering input device but relying in devres to free
interrupt handler which (unless device is properly shut off) can cause
ISR to reference already freed memory.

This change introduces devm_input_allocate_device() that will allocate
managed instance of input device so that driver writers who prefer
using devm_* framework do not have to mix 2 styles.

Reviewed-by: Henrik Rydberg <rydberg@euromail.se>
Reviewed-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

1 files changed, 6 insertions, 1 deletions

diff --git a/include/linux/input.h b/include/linux/input.h
index cab994ba6d91..5538cc09a4f5 100644
--- a/include/linux/input.h
+++ b/include/linux/input.h
@@ -112,6 +112,8 @@ struct input_value {
  * @h_list: list of input handles associated with the device. When
  *      accessing the list dev->mutex must be held
  * @node: used to place the device onto input_dev_list
+ * @devres_managed: indicates that devices is managed with devres framework
+ *      and needs not be explicitly unregistered or freed.
  */
 struct input_dev {
         const char *name;
@@ -180,6 +182,8 @@ struct input_dev {
         unsigned int num_vals;
         unsigned int max_vals;
         struct input_value *vals;
+
+        bool devres_managed;
 };
 #define to_input_dev(d) container_of(d, struct input_dev, dev)
 
@@ -323,7 +327,8 @@ struct input_handle {
         struct list_head        h_node;
 };
 
-struct input_dev *input_allocate_device(void);
+struct input_dev __must_check *input_allocate_device(void);
+struct input_dev __must_check *devm_input_allocate_device(struct device *);
 void input_free_device(struct input_dev *dev);
 
 static inline struct input_dev *input_get_device(struct input_dev *dev)