On Mon, Nov 07, 2016 at 02:39:12AM +0000, Bard Liao wrote:

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No, that's something the regulator API will handle for you - individual drivers should be written with sensible error handling, the regulator API will handle stubbing out things that are needed.

Sorry, maybe I didn't describe it clear. What I mean is all power pins needed by rt5665 codec can be connected by hardware directly without SW control. There is no specific power sequence for these power pins. So, we don't need to control them by driver. That's why we think they are optional.

That's exactly what I understood you to mean. The regulator API will hide this for you.