[RFC PATCH v2] protocol: Extend wayland seat with interfaces for sensor inputs.

[Stefan Schmidt]

Treating some specific sensors as input devices. In particular
adding support for wl_compass, wl_gyroscope and wl_accelerometer here.

Using these sensor as input for apps and games. Not covering any
background apps or services with this protocol.

We have requests to start and stop sensor event receiving as well as
events to receive the different axis values for these sensors.

V2:
o Add units to event arguments
o Define coordinate system
o Be more verbose on security policy in compositor and add error event

Signed-off-by: Stefan Schmidt <s.schmidt at samsung.com>
---
 protocol/wayland.xml |  175 ++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 175 insertions(+)

diff --git a/protocol/wayland.xml b/protocol/wayland.xml
index d7bbbb9..e35413c 100644
--- a/protocol/wayland.xml
+++ b/protocol/wayland.xml
@@ -1251,6 +1251,9 @@
       <entry name="pointer" value="1" summary="The seat has pointer devices"/>
       <entry name="keyboard" value="2" summary="The seat has one or more keyboards"/>
       <entry name="touch" value="4" summary="The seat has touch devices"/>
+      <entry name="compass" value="8" summary="The seat has compass devices"/>
+      <entry name="gyroscope" value="16" summary="The seat has gyroscope devices"/>
+      <entry name="accelerometer" value="32" summary="The seat has accelerometer devices"/>
     </enum>
 
     <event name="capabilities">
@@ -1297,6 +1300,63 @@
 
     <!-- Version 2 of additions -->
 
+    <request name="get_compass" since="2">
+      <description summary="return compass object">
+        The ID provided will be initialized to the wl_compass interface
+	for this seat.
+
+        This request only takes effect if the seat has the compass
+        capability. If the seat has the capability but no object is
+        received it could be that the compositor security policy has
+        denied the sensor access for the client. In case of a security
+        policy error an error event will be send.
+      </description>
+      <arg name="id" type="new_id" interface="wl_compass"/>
+    </request>
+
+    <request name="get_gyroscope" since="2">
+      <description summary="return gyroscope object">
+        The ID provided will be initialized to the wl_gyroscope interface
+	for this seat.
+
+        This request only takes effect if the seat has the gyroscope
+        capability. If the seat has the capability but no object is
+        received it could be that the compositor security policy has
+        denied the sensor access for the client. In case of a security
+        policy error an error event will be send.
+      </description>
+      <arg name="id" type="new_id" interface="wl_gyroscope"/>
+    </request>
+
+    <request name="get_accelerometer" since="2">
+      <description summary="return accelerometer object">
+        The ID provided will be initialized to the wl_accelerometer interface
+	for this seat.
+
+        This request only takes effect if the seat has the accelerometer
+        capability. If the seat has the capability but no object is
+        received it could be that the compositor security policy has
+        denied the sensor access for the client. In case of a security
+        policy error an error event will be send.
+      </description>
+      <arg name="id" type="new_id" interface="wl_accelerometer"/>
+    </request>
+
+    <event name="error">
+      <description summary="fatal error event">
+	The error event is sent out when a fatal (non-recoverable)
+	error has occurred.  The object_id argument is the object
+	where the error occurred, most often in response to a request
+	to that object.  The code identifies the error and is defined
+	by the object interface.  As such, each interface defines its
+	own set of error codes.  The message is an brief description
+	of the error, for (debugging) convenience.
+      </description>
+      <arg name="object_id" type="object"/>
+      <arg name="code" type="uint"/>
+      <arg name="message" type="string"/>
+    </event>
+
     <event name="name" since="2">
       <description summary="unique identifier for this seat">
 	In a multiseat configuration this can be used by the client to help
@@ -1605,6 +1665,121 @@
     </event>
   </interface>
 
+  <interface name="wl_compass" version="2">
+    <description summary="compass sensor device">
+      The wl_compass interface represents a compass
+      associated with a seat.
+    </description>
+
+    <request name="start">
+      <description summary="Start receiving events">
+	Sent to enable event receiving for the compass sensor.
+      </description>
+    </request>
+
+    <request name="stop">
+      <description summary="Stop receiving events">
+	Sent to disable event receiving for the compass sensor.
+
+	It stops event reporting to this client. Other clients might still
+	receive events.
+      </description>
+    </request>
+
+    <event name="motion">
+      <description summary="Motion event coming from the compass sensor">
+	Updated sensor data available from compass
+
+	Measurement of the ambient magnetic field in the X, Y and Z axis.
+
+	Coordinate system (device in portrait mode with screen facing upwards):
+	X axis goes from the left to the right side of the device
+	Y axis goes from the bottom of the screen to the top
+	Z axis goes from the back of the screen to the front of the screen
+     </description>
+      <arg name="x" type="fixed" summary="x-axis in micro Tesla (uT)"/>
+      <arg name="y" type="fixed" summary="y-axis in micro Tesla (uT)"/>
+      <arg name="z" type="fixed" summary="z-axis in micro Tesla (uT)"/>
+    </event>
+  </interface>
+
+  <interface name="wl_gyroscope" version="2">
+    <description summary="gyroscope sensor device">
+      The wl_gyroscope interface represents a gyroscope
+      associated with a seat.
+    </description>
+
+    <request name="start">
+      <description summary="Start receiving events">
+	Sent to enable event receiving for the gyroscope sensor.
+      </description>
+    </request>
+
+    <request name="stop">
+      <description summary="Stop receiving events">
+	Sent to disable event receiving for the gyroscope sensor.
+
+	It stops event reporting to this client. Other clients might still
+	receive events.
+      </description>
+    </request>
+
+    <event name="motion">
+      <description summary="Motion event coming from the gyroscope sensor">
+	Updated sensor data available from gyroscope
+
+	Measurement of the rate of rotation around X, Y and Z axis in degree per second.
+	Values are observed in positive notation in the counter-clockwise direction.
+
+	Coordinate system (device in portrait mode with screen facing upwards):
+	X axis goes from the left to the right side of the device (Pitch)
+	Y axis goes from the bottom of the screen to the top (Roll)
+	Z axis goes from the back of the screen to the front of the screen (Azimuth/Yaw)
+      </description>
+      <arg name="x" type="fixed" summary="x-axis in degree per second"/>
+      <arg name="y" type="fixed" summary="y-axis in degree per second"/>
+      <arg name="z" type="fixed" summary="z-axis in degree per second"/>
+    </event>
+  </interface>
+
+  <interface name="wl_accelerometer" version="2">
+    <description summary="accelerometer sensor device">
+      The wl_accelerometer interface represents a accelerometer
+      associated with a seat.
+    </description>
+
+    <request name="start">
+      <description summary="Start receiving events">
+	Sent to enable event receiving for the accelerometer sensor.
+      </description>
+    </request>
+
+    <request name="stop">
+      <description summary="Stop receiving events">
+	Sent to disable event receiving for the accelerometer sensor.
+
+	It stops event reporting to this client. Other clients might still
+	receive events.
+      </description>
+    </request>
+
+    <event name="motion">
+      <description summary="Motion event coming from the accelerometer sensor">
+	Updated sensor data available from accelerometer
+
+	Measurement of the acceleration of G on the axis in m/s^2.
+
+	Coordinate system (device in portrait mode with screen facing upwards):
+	X axis goes from the left to the right side of the device
+	Y axis goes from the bottom of the screen to the top
+	Z axis goes from the back of the screen to the front of the screen
+      </description>
+      <arg name="x" type="fixed" summary="x-axis G in m/s^2"/>
+      <arg name="y" type="fixed" summary="y-axis G in m/s^2"/>
+      <arg name="z" type="fixed" summary="z-axis G in m/s^2"/>
+    </event>
+  </interface>
+
   <interface name="wl_output" version="2">
     <description summary="compositor output region">
       An output describes part of the compositor geometry.  The
-- 
1.7.9.5