In CA, can you use an entire 529 withdrawal for private high school tuition? Or just the contribution and the earnings are taxable?Federally, neither are taxable correct?

No the 529 isn't eligible in CA with possible penalties. The federal allows the 529 for high school. 

Using 529 Savings Plans for Private School Tuition - Saving for College states:

Although California residents can access the same federal tax benefits of using a 529 for high school, their state tax will be adversely affected. California considers 529 withdrawals for secondary school tuition a non-qualified distribution and even imposes a penalty.

Can you please provide details on how penalties are calculated, to both contributions and earnings in the state of CA if a 529 is used for private high school tuition.

Can you please provide details on how penalties are calculated, to both contributions and earnings in the state of CA if a 529 is used for private high school tuition.

From Frequently Asked Questions - ScholarShare 529:

How are withdrawals for nonqualified expenses taxed?

The earnings portion of a non-qualified withdrawal is subject to federal income taxation, and an additional 10% federal tax. For California taxpayers, the earnings portion of a non-qualified withdrawal may also be subject to California income tax and an additional 2.5% tax. See the Plan Description for details.