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, 250 insertions, 0 deletions

diff --git a/drivers/input/sparse-keymap.c b/drivers/input/sparse-keymap.c
new file mode 100644
index 00000000000..fbd3987af57
--- /dev/null
+++ b/drivers/input/sparse-keymap.c
@@ -0,0 +1,250 @@
+/*
+ * Generic support for sparse keymaps
+ *
+ * Copyright (c) 2009 Dmitry Torokhov
+ *
+ * Derived from wistron button driver:
+ * Copyright (C) 2005 Miloslav Trmac <mitr@volny.cz>
+ * Copyright (C) 2005 Bernhard Rosenkraenzer <bero@arklinux.org>
+ * Copyright (C) 2005 Dmitry Torokhov <dtor@mail.ru>
+ *
+ * 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/input/sparse-keymap.h>
+
+MODULE_AUTHOR("Dmitry Torokhov <dtor@mail.ru>");
+MODULE_DESCRIPTION("Generic support for sparse keymaps");
+MODULE_LICENSE("GPL v2");
+MODULE_VERSION("0.1");
+
+/**
+ * sparse_keymap_entry_from_scancode - perform sparse keymap lookup
+ * @dev: Input device using sparse keymap
+ * @code: Scan code
+ *
+ * This function is used to perform &struct key_entry lookup in an
+ * input device using sparse keymap.
+ */
+struct key_entry *sparse_keymap_entry_from_scancode(struct input_dev *dev,
+						    unsigned int code)
+{
+	struct key_entry *key;
+
+	for (key = dev->keycode; key->type != KE_END; key++)
+		if (code == key->code)
+			return key;
+
+	return NULL;
+}
+EXPORT_SYMBOL(sparse_keymap_entry_from_scancode);
+
+/**
+ * sparse_keymap_entry_from_keycode - perform sparse keymap lookup
+ * @dev: Input device using sparse keymap
+ * @keycode: Key code
+ *
+ * This function is used to perform &struct key_entry lookup in an
+ * input device using sparse keymap.
+ */
+struct key_entry *sparse_keymap_entry_from_keycode(struct input_dev *dev,
+						   unsigned int keycode)
+{
+	struct key_entry *key;
+
+	for (key = dev->keycode; key->type != KE_END; key++)
+		if (key->type == KE_KEY && keycode == key->keycode)
+			return key;
+
+	return NULL;
+}
+EXPORT_SYMBOL(sparse_keymap_entry_from_keycode);
+
+static int sparse_keymap_getkeycode(struct input_dev *dev,
+				    int scancode, int *keycode)
+{
+	const struct key_entry *key =
+			sparse_keymap_entry_from_scancode(dev, scancode);
+
+	if (key && key->type == KE_KEY) {
+		*keycode = key->keycode;
+		return 0;
+	}
+
+	return -EINVAL;
+}
+
+static int sparse_keymap_setkeycode(struct input_dev *dev,
+				    int scancode, int keycode)
+{
+	struct key_entry *key;
+	int old_keycode;
+
+	if (keycode < 0 || keycode > KEY_MAX)
+		return -EINVAL;
+
+	key = sparse_keymap_entry_from_scancode(dev, scancode);
+	if (key && key->type == KE_KEY) {
+		old_keycode = key->keycode;
+		key->keycode = keycode;
+		set_bit(keycode, dev->keybit);
+		if (!sparse_keymap_entry_from_keycode(dev, old_keycode))
+			clear_bit(old_keycode, dev->keybit);
+		return 0;
+	}
+
+	return -EINVAL;
+}
+
+/**
+ * sparse_keymap_setup - set up sparse keymap for an input device
+ * @dev: Input device
+ * @keymap: Keymap in form of array of &key_entry structures ending
+ *	with %KE_END type entry
+ * @setup: Function that can be used to adjust keymap entries
+ *	depending on device's deeds, may be %NULL
+ *
+ * The function calculates size and allocates copy of the original
+ * keymap after which sets up input device event bits appropriately.
+ * Before destroying input device allocated keymap should be freed
+ * with a call to sparse_keymap_free().
+ */
+int sparse_keymap_setup(struct input_dev *dev,
+			const struct key_entry *keymap,
+			int (*setup)(struct input_dev *, struct key_entry *))
+{
+	size_t map_size = 1; /* to account for the last KE_END entry */
+	const struct key_entry *e;
+	struct key_entry *map, *entry;
+	int i;
+	int error;
+
+	for (e = keymap; e->type != KE_END; e++)
+		map_size++;
+
+	map = kcalloc(map_size, sizeof (struct key_entry), GFP_KERNEL);
+	if (!map)
+		return -ENOMEM;
+
+	memcpy(map, keymap, map_size * sizeof (struct key_entry));
+
+	for (i = 0; i < map_size; i++) {
+		entry = &map[i];
+
+		if (setup) {
+			error = setup(dev, entry);
+			if (error)
+				goto err_out;
+		}
+
+		switch (entry->type) {
+		case KE_KEY:
+			__set_bit(EV_KEY, dev->evbit);
+			__set_bit(entry->keycode, dev->keybit);
+			break;
+
+		case KE_SW:
+			__set_bit(EV_SW, dev->evbit);
+			__set_bit(entry->sw.code, dev->swbit);
+			break;
+		}
+	}
+
+	dev->keycode = map;
+	dev->keycodemax = map_size;
+	dev->getkeycode = sparse_keymap_getkeycode;
+	dev->setkeycode = sparse_keymap_setkeycode;
+
+	return 0;
+
+ err_out:
+	kfree(keymap);
+	return error;
+
+}
+EXPORT_SYMBOL(sparse_keymap_setup);
+
+/**
+ * sparse_keymap_free - free memory allocated for sparse keymap
+ * @dev: Input device using sparse keymap
+ *
+ * This function is used to free memory allocated by sparse keymap
+ * in an input device that was set up by sparse_keymap_setup().
+ */
+void sparse_keymap_free(struct input_dev *dev)
+{
+	kfree(dev->keycode);
+	dev->keycode = NULL;
+	dev->keycodemax = 0;
+	dev->getkeycode = NULL;
+	dev->setkeycode = NULL;
+}
+EXPORT_SYMBOL(sparse_keymap_free);
+
+/**
+ * sparse_keymap_report_entry - report event corresponding to given key entry
+ * @dev: Input device for which event should be reported
+ * @ke: key entry describing event
+ * @value: Value that should be reported (ignored by %KE_SW entries)
+ * @autorelease: Signals whether release event should be emitted for %KE_KEY
+ *	entries right after reporting press event, ignored by all other
+ *	entries
+ *
+ * This function is used to report input event described by given
+ * &struct key_entry.
+ */
+void sparse_keymap_report_entry(struct input_dev *dev, const struct key_entry *ke,
+				unsigned int value, bool autorelease)
+{
+	switch (ke->type) {
+	case KE_KEY:
+		input_report_key(dev, ke->keycode, value);
+		input_sync(dev);
+		if (value && autorelease) {
+			input_report_key(dev, ke->keycode, 0);
+			input_sync(dev);
+		}
+		break;
+
+	case KE_SW:
+		value = ke->sw.value;
+		/* fall through */
+
+	case KE_VSW:
+		input_report_switch(dev, ke->sw.code, value);
+		break;
+	}
+}
+EXPORT_SYMBOL(sparse_keymap_report_entry);
+
+/**
+ * sparse_keymap_report_event - report event corresponding to given scancode
+ * @dev: Input device using sparse keymap
+ * @code: Scan code
+ * @value: Value that should be reported (ignored by %KE_SW entries)
+ * @autorelease: Signals whether release event should be emitted for %KE_KEY
+ *	entries right after reporting press event, ignored by all other
+ *	entries
+ *
+ * This function is used to perform lookup in an input device using sparse
+ * keymap and report corresponding event. Returns %true if lookup was
+ * successful and %false otherwise.
+ */
+bool sparse_keymap_report_event(struct input_dev *dev, unsigned int code,
+				unsigned int value, bool autorelease)
+{
+	const struct key_entry *ke =
+		sparse_keymap_entry_from_scancode(dev, code);
+
+	if (ke) {
+		sparse_keymap_report_entry(dev, ke, value, autorelease);
+		return true;
+	}
+
+	return false;
+}
+EXPORT_SYMBOL(sparse_keymap_report_event);
+