Input Services is the core system that operates the PKB and Touch Screen on the Passport.
When you have the device idle, make sure nothing is touching the screen or keys as that will cause the BlackBerry to ramp up CPU usage for Input Services.
It can also get glitched and "stuck on", a Soft Reset will normally fix that, see: http://forums.crackberry.com/blackbe.../#post12573902
Also, on your Battery Usage Device Monitor screen, if you tap the entries shown, you get a new screen with all usage data and graphs for the service or app you tapped.
That will provide a much clearer picture of what is going on with a high usage service or app.
So, tap your Input Services icon and see what exactly is happening.