Input: add generic support for sparse keymaps

More and more devices choose to reimplement support for sparse keymaps
first introduced by wistron driver. Move it into a library module so it
can be easily used by interested parties.

Reviewed-by: Anisse Astier <anisse@astier.eu>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>

1 files changed, 62 insertions, 0 deletions

diff --git a/include/linux/input/sparse-keymap.h b/include/linux/input/sparse-keymap.h
new file mode 100644
index 0000000..52db620
--- /dev/null
+++ b/include/linux/input/sparse-keymap.h
@@ -0,0 +1,62 @@
+#ifndef _SPARSE_KEYMAP_H
+#define _SPARSE_KEYMAP_H
+
+/*
+ * Copyright (c) 2009 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.
+ */
+
+#define KE_END		0	/* Indicates end of keymap */
+#define KE_KEY		1	/* Ordinary key/button */
+#define KE_SW		2	/* Switch (predetermined value) */
+#define KE_VSW		3	/* Switch (value supplied at runtime) */
+#define KE_IGNORE	4	/* Known entry that should be ignored */
+#define KE_LAST		KE_IGNORE
+
+/**
+ * struct key_entry - keymap entry for use in sparse keymap
+ * @type: Type of the key entry (KE_KEY, KE_SW, KE_VSW, KE_END);
+ *	drivers are allowed to extend the list with their own
+ *	private definitions.
+ * @code: Device-specific data identifying the button/switch
+ * @keycode: KEY_* code assigned to a key/button
+ * @sw.code: SW_* code assigned to a switch
+ * @sw.value: Value that should be sent in an input even when KE_SW
+ *	switch is toggled. KE_VSW switches ignore this field and
+ *	expect driver to supply value for the event.
+ *
+ * This structure defines an entry in a sparse keymap used by some
+ * input devices for which traditional table-based approach is not
+ * suitable.
+ */
+struct key_entry {
+	int type;		/* See KE_* above */
+	u32 code;
+	union {
+		u16 keycode;		/* For KE_KEY */
+		struct {		/* For KE_SW, KE_VSW */
+			u8 code;
+			u8 value;	/* For KE_SW, ignored by KE_VSW */
+		} sw;
+	};
+};
+
+struct key_entry *sparse_keymap_entry_from_scancode(struct input_dev *dev,
+						    unsigned int code);
+struct key_entry *sparse_keymap_entry_from_keycode(struct input_dev *dev,
+						   unsigned int code);
+int sparse_keymap_setup(struct input_dev *dev,
+			const struct key_entry *keymap,
+			int (*setup)(struct input_dev *, struct key_entry *));
+void sparse_keymap_free(struct input_dev *dev);
+
+void sparse_keymap_report_entry(struct input_dev *dev, const struct key_entry *ke,
+				unsigned int value, bool autorelease);
+
+bool sparse_keymap_report_event(struct input_dev *dev, unsigned int code,
+				unsigned int value, bool autorelease);
+
+#endif /* _SPARSE_KEYMAP_H */