[dev] add primitive keys state management (keys device)
diff --git a/dev/keys/keys.c b/dev/keys/keys.c
new file mode 100644
index 0000000..3e7c452
--- /dev/null
+++ b/dev/keys/keys.c
@@ -0,0 +1,67 @@
+/*
+ * Copyright (c) 2008, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *  * Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ *  * Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ *  * Neither the name of Google, Inc. nor the names of its contributors
+ *    may be used to endorse or promote products derived from this
+ *    software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+ * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <bits.h>
+#include <debug.h>
+#include <string.h>
+#include <dev/keys.h>
+
+static unsigned long key_bitmap[BITMAP_NUM_WORDS(MAX_KEYS)];
+
+void keys_init(void)
+{
+	memset(key_bitmap, 0, sizeof(key_bitmap));
+}
+
+void keys_post_event(uint16_t code, int16_t value)
+{
+	if (code >= MAX_KEYS) {
+		dprintf(INFO, "Invalid keycode posted: %d\n", code);
+		return;
+	}
+
+	/* TODO: Implement an actual event queue if it becomes necessary */
+	if (value)
+		bitmap_set(key_bitmap, code);
+	else
+		bitmap_clear(key_bitmap, code);
+
+//	dprintf(INFO, "key state change: %d %d\n", code, value);
+}
+
+int keys_get_state(uint16_t code)
+{
+	if (code >= MAX_KEYS) {
+		dprintf(INFO, "Invalid keycode requested: %d\n", code);
+		return -1;
+	}
+	return bitmap_test(key_bitmap, code);
+}