On your W-2, the Box 12 code W
amount includes both the employer and employee pre-tax
contributions, including incentives. If you contributed to your
HSA only through payroll deductions, do not enter them
anywhere else in TurboTax. Payroll contributions reduce your wages and you wouldn't be taxed on the amounts.
Also, be certain to indicate that you
were enrolled in a HDHP. This is a requirement for the
participation in an HSA. If you miss entering this information, the
program will calculate a contribution penalty.