[new driver] allwinner/ac100: rtc and audio codec for a83t

[kevans]

Summary

The X-Powers AC100 provides an RTC and an audio codec to at least the Banana Pi-M3 (a83t). Driver is ported from NetBSD, currently only supports the RTC bits.

[kevans]

Spacing nits

[kevans]

Sorry, should be the last correction for now- simplified the ofw compat bits.

[manu]

sys/arm/allwinner/files.allwinner

16

This should by optional ac100

[andrew]

It feels like this should be 2 drivers. One to talk with the ac100, and a second jsut for the rtc bits.

[manu]

In D13136#273671, @andrew wrote:

It feels like this should be 2 drivers. One to talk with the ac100, and a second jsut for the rtc bits.

You never talk to the ac100, only to the rtc bits or the coded bits.
This is what DT calls MFD (Multi Function Device) and I never knew what is the best way to represent it in our drivers.

[kevans]

standard -> optional ac100, add ac100 to the arm/GENERIC config near rsb and axp209/axp81x.

[emaste]

This is what DT calls MFD (Multi Function Device) and I never knew what is the best way to represent it in our drivers.

How would an eventual codec driver interact with this one?

[kevans]

In D13136#283192, @emaste wrote:

This is what DT calls MFD (Multi Function Device) and I never knew what is the best way to represent it in our drivers.

How would an eventual codec driver interact with this one?

AFAICT, it's intended that the AC100 bits should be an all-in-one kind of driver, thus the codec driver would "attach" like the RTC does here; not actually having its own resources or anything to that effect, and sharing a context with the RTC.