Add input HAL header.

Change-Id: Ia959dd1d1adf024459d2423fc9d59a811466e53c
diff --git a/include/hardware/input.h b/include/hardware/input.h
new file mode 100644
index 0000000..dad1bc0
--- /dev/null
+++ b/include/hardware/input.h
@@ -0,0 +1,176 @@
+/*
+ * Copyright (C) 2015 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef ANDROID_INCLUDE_HARDWARE_INPUT_H
+#define ANDROID_INCLUDE_HARDWARE_INPUT_H
+
+#include <hardware/hardware.h>
+#include <stdint.h>
+
+__BEGIN_DECLS
+
+#define INPUT_MODULE_API_VERSION_1_0 HARDWARE_MODULE_API_VERSION(1, 0)
+#define INPUT_HARDWARE_MODULE_ID "input"
+
+#define INPUT_INSTANCE_EVDEV "evdev"
+
+typedef enum input_bus {
+    INPUT_BUS_BT,
+    INPUT_BUS_USB,
+    INPUT_BUS_SERIAL,
+    INPUT_BUS_BUILTIN
+} input_bus_t;
+
+typedef struct input_host input_host_t;
+
+typedef struct input_device_handle input_device_handle_t;
+
+typedef struct input_device_identifier input_device_identifier_t;
+
+typedef struct input_device_definition input_device_definition_t;
+
+typedef struct input_report_definition input_report_definition_t;
+
+typedef struct input_report input_report_t;
+
+typedef struct input_collection input_collection_t;
+
+typedef enum {
+    INPUT_USAGE_TOUCHPAD_X,
+    INPUT_USAGE_TOUCHPAD_Y,
+    // etc
+} input_usage_t;
+
+typedef enum {
+    INPUT_COLLECTION_ID_TOUCH,
+    INPUT_COLLECTION_ID_KEYBOARD,
+    INPUT_COLLECTION_ID_MOUSE,
+    INPUT_COLLECTION_ID_TOUCHPAD,
+    // etc
+} input_collection_id_t;
+
+typedef struct input_message input_message_t;
+
+typedef struct input_host_callbacks {
+
+    /**
+     * Creates a device identifier with the given properties.
+     * The unique ID should be a string that precisely identifies a given piece of hardware. For
+     * example, an input device connected via Bluetooth could use its MAC address as its unique ID.
+     */
+    input_device_identifier_t* (*create_device_identifier)(input_host_t* host,
+            const char* name, int32_t product_id, int32_t vendor_id,
+            input_bus_t bus, const char* unique_id);
+
+    /**
+     * Allocates the device definition which will describe the input capabilities of a device. A
+     * device definition may be used to register as many devices as desired.
+     */
+    input_device_definition_t* (*create_device_definition)(input_host_t* host);
+
+    /**
+     * Allocate either an input report, which the HAL will use to tell the host of incoming input
+     * events, or an output report, which the host will use to tell the HAL of desired state
+     * changes (e.g. setting an LED).
+     */
+    input_report_definition_t* (*create_input_report_definition)(input_host_t* host);
+    input_report_definition_t* (*create_output_report_definition)(input_host_t* host);
+
+    /**
+     * Append the report to the given input device.
+     */
+    void (*input_device_definition_add_report)(input_host_t* host,
+            input_device_definition_t* d, input_report_definition_t* r);
+
+    /**
+     * Add a collection with the given arity and ID. A collection describes a set
+     * of logically grouped properties such as the X and Y coordinates of a single finger touch or
+     * the set of keys on a keyboard. The arity declares how many repeated instances of this
+     * collection will appear in whatever report it is attached to. The ID describes the type of
+     * grouping being represented by the collection. For example, a touchscreen capable of
+     * reporting up to 2 fingers simultaneously might have a collection with the X and Y
+     * coordinates, an arity of 2, and an ID of INPUT_COLLECTION_USAGE_TOUCHSCREEN. Any given ID
+     * may only be present once for a given report.
+     */
+    void (*input_report_definition_add_collection)(input_host_t* host,
+            input_report_definition_t* report, input_collection_id_t id, int32_t arity);
+
+    /**
+     * Declare an int usage with the given properties. The report and collection defines where the
+     * usage is being declared.
+     */
+    void (*input_report_definition_declare_usage_int)(input_host_t* host,
+            input_report_definition_t* report, input_collection_id_t id,
+            input_usage_t usage, int32_t min, int32_t max, float resolution);
+
+    /**
+     * Declare a set of boolean usages with the given properties.  The report and collection
+     * defines where the usages are being declared.
+     */
+    void (*input_report_definition_declare_usages_bool)(input_host_t* host,
+            input_report_definition_t* report, input_collection_id_t id,
+            input_usage_t* usage, size_t usage_count);
+
+
+    /**
+     * Register a given input device definition. This notifies the host that an input device has
+     * been connected and gives a description of all its capabilities.
+     */
+    input_device_handle_t* (*register_device)(input_host_t* host,
+            input_device_identifier_t* id, input_device_definition_t* d);
+
+    /** Unregister the given device */
+    void (*unregister_device)(input_host_t* host, input_device_handle_t* handle);
+
+    /**
+     * Allocate a report that will contain all of the state as described by the given report.
+     */
+    input_report_t* (*input_allocate_report)(input_host_t* host, input_report_definition_t* r);
+
+    void (*report_event)(input_host_t* host, input_device_handle_t* d, input_report_t* report);
+} input_host_callbacks_t;
+
+typedef struct input_module input_module_t;
+
+struct input_module {
+    /**
+     * Common methods of the input module. This *must* be the first member
+     * of input_module as users of this structure will cast a hw_module_t
+     * to input_module pointer in contexts where it's known
+     * the hw_module_t references a input_module.
+     */
+    struct hw_module_t common;
+
+    /**
+     * Initialize the module with host callbacks. At this point the HAL should start up whatever
+     * infrastructure it needs to in order to process input events.
+     */
+    void (*init)(const input_module_t* module, input_host_t* host, input_host_callbacks_t cb);
+
+    /**
+     * Sends an output report with a new set of state the host would like the given device to
+     * assume.
+     */
+    void (*notify_report)(input_report_t* report);
+};
+
+static inline int input_open(const struct hw_module_t** module, const char* type) {
+    return hw_get_module_by_class(INPUT_HARDWARE_MODULE_ID, type, module);
+}
+
+__END_DECLS
+
+#endif  /* ANDROID_INCLUDE_HARDWARE_INPUT_H */