Input: add skeleton for simple polled devices

input-polldev provides a skeleton for supporting simple input
devices that need to be periodically scanned or polled to
detect changes in their state.

Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
diff --git a/include/linux/input-polldev.h b/include/linux/input-polldev.h
new file mode 100644
index 0000000..597a007
--- /dev/null
+++ b/include/linux/input-polldev.h
@@ -0,0 +1,46 @@
+#ifndef _INPUT_POLLDEV_H
+#define _INPUT_POLLDEV_H
+
+/*
+ * Copyright (c) 2007 Dmitry Torokhov
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published by
+ * the Free Software Foundation.
+ */
+
+#include <linux/input.h>
+#include <linux/workqueue.h>
+
+/**
+ * struct input_polled_dev - simple polled input device
+ * @private: private driver data
+ * @flush: driver-supplied method that flushes device's state upon
+ *	opening (optional)
+ * @poll: driver-supplied method that polls the device and posts
+ *	input events (mandatory).
+ * @poll_interval: specifies how often the poll() method shoudl be called.
+ * @input: input device structire associated with the polled device.
+ *	Must be properly initialized by the driver (id, name, phys, bits).
+ *
+ * Polled input device provides a skeleton for supporting simple input
+ * devices that do not raise interrupts but have to be periodically
+ * scanned or polled to detect changes in their state.
+ */
+struct input_polled_dev {
+	void *private;
+
+	void (*flush)(struct input_polled_dev *dev);
+	void (*poll)(struct input_polled_dev *dev);
+	unsigned int poll_interval; /* msec */
+
+	struct input_dev *input;
+	struct delayed_work work;
+};
+
+struct input_polled_dev *input_allocate_polled_device(void);
+void input_free_polled_device(struct input_polled_dev *dev);
+int input_register_polled_device(struct input_polled_dev *dev);
+void input_unregister_polled_device(struct input_polled_dev *dev);
+
+#endif