Accelerometer: Use motionsense HC to get number of sensors

If no sensors available, abort AccelerometerClient.
Next step is to find which sensor is at which index.

Signed-off-by: Daniel Schaefer <dhs@frame.work>

Author: JohnAZoidberg

FrameworkSensors/AccelerometerClient.cpp

@@ -38,6 +38,29 @@ typedef enum
     ACCELEROMETER_DATA_COUNT
 } ACCELEROMETER_DATA_INDEX;
 
+UINT8 CrosEcGetMotionSensorCount(HANDLE Handle)
+{
+    EC_REQUEST_MOTION_SENSE_DUMP req{};
+    EC_RESPONSE_MOTION_SENSE_DUMP res{};
+
+    req.MaxSensorCount = 0;
+    if (0 == CrosEcSendCommand(
+        Handle,
+        EC_CMD_MOTION_SENSE,
+        0,
+        &req,
+        sizeof(req),
+        &res,
+        sizeof(res)
+    )) {
+        TraceError("%!FUNC! EC_CMD_MOTION_SENSE_DUMP failed");
+        return 0;
+    }
+
+    return res.SensorCount;
+}
+
+
 //------------------------------------------------------------------------------
 // Function: Initialize
 //
@@ -57,6 +80,8 @@ AccelerometerDevice::Initialize(
     )
 {
     NTSTATUS Status = STATUS_SUCCESS;
+    UINT8 SensorCount = 0;
+    PComboDevice Context = GetContextFromSensorInstance(SensorInstance);
 
     SENSOR_FunctionEnter();
 
@@ -67,6 +92,15 @@ AccelerometerDevice::Initialize(
     m_SensorInstance = SensorInstance;
     m_Started = FALSE;
 
+    SensorCount = CrosEcGetMotionSensorCount(Context->m_CrosEcHandle);
+    TraceInformation("%!FUNC! Found %d Sensors on this device", SensorCount);
+    if (SensorCount == 0)
+    {
+        TraceError("%!FUNC! No Sensors available. Not initializing AccelerometerClient");
+        Status = STATUS_NOT_FOUND;
+        goto Exit;
+    }
+
     //
     // Create Lock
     //

FrameworkSensors/EcCommunication.h

@@ -49,6 +49,7 @@ NTSTATUS ConnectToEc(
 	_Inout_ HANDLE* Handle
 );
 
+#define EC_CMD_MOTION_SENSE     0x002B
 #define EC_CMD_RGBKBD_SET_COLOR 0x013A
 #define EC_CMD_RGBKBD           0x013B
 
@@ -93,6 +94,19 @@ typedef struct {
 	Rgb Colors[CROS_EC_CMD_MAX_KEY_COUNT];
 } EC_REQUEST_RGB_KBD_SET_COLOR;
 
+typedef struct {
+	UINT8 MaxSensorCount;
+} EC_REQUEST_MOTION_SENSE_DUMP;
+
+typedef struct {
+	UINT8 MaxSensorCount;
+	UINT8 SensorCount;
+	// Need to allocate extra data if you care about this field.
+	// Right now I only care about the count.
+	// If this field is not there, the EC just truncates the response.
+	// UINT8 Sensors[];
+} EC_RESPONSE_MOTION_SENSE_DUMP;
+
 #include <poppack.h>
 
 int CrosEcSendCommand(