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simple-pm-bus driver
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Authored by oskar.holmlund_ohdata.se on Jul 26 2021, 6:53 PM.
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manu
mmel
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ARM
arm64
Summary

Add a simple-pm-bus driver to get AM335x to boot.
If the DTS node contains a clock it will be enabled later in the boot process.

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rG FreeBSD src repository
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oskar.holmlund_ohdata.se created this revision.

D27889 are required to get AM335x to boot.

Any reason the clock are enabled after interrupts ? I suspect that some stuff will rely on the clock being activated at attach.
The bindings have this comment :

Hence, the bus controller's PM domain and/or
clock must be enabled for child devices connected to the bus (either
on-SoC or externally) to function.

It also seems that some TI nodes doesn't respect the bindings as they have no clocks or power-domain property, are we relying on u-boot for those to work ?

sys/dev/fdt/simplepmbus.c
105

Doesn't seems to be true, I think we can have multiple clocks.

sys/dev/fdt/simplepmbus.c
113

I've missed that the first time, any reason we don't enable the clock directly ?

So, apparently the goal of simple-pm-bus is only to enable runtime pm in the Linux kernel for the whole child tree, while simple-bus doesn't do that.
Apparently the bindings are wrong suggesting that either power-domain or clock is required and the Linux code seems to indicate this ...