[PATCH 00/16] Add initial USB support for the Renesas RZ/G3S SoC

[Ulf Hansson]

On Thu, 22 Aug 2024 at 17:28, Claudiu <claudiu.beznea at tuxon.dev> wrote:
>
> From: Claudiu Beznea <claudiu.beznea.uj at bp.renesas.com>
>
> Hi,
>
> Series adds initial USB support for the Renesas RZ/G3S SoC.
>
> Series is split as follows:
>
> - patch 01/16           - add clock reset and power domain support for USB
> - patch 02-04/16        - add reset control support for a USB signal
>                           that need to be controlled before/after
>                           the power to USB area is turned on/off.
>
>                           Philipp, Ulf, Geert, all,
>
>                           I detailed my approach for this in patch
>                           04/16, please have a look and let me know
>                           your input.

I have looked briefly. Your suggested approach may work, but I have a
few thoughts, see below.

If I understand correctly, it is the consumer driver for the device
that is attached to the USB power domain that becomes responsible for
asserting/de-asserting this new signal. Right?

In this regard, please note that the consumer driver doesn't really
know when the power domain really gets powered-on/off. Calling
pm_runtime_get|put*() is dealing with the reference counting. For
example, a call to pm_runtime_get*() just makes sure that the PM
domain gets-or-remains powered-on. Could this be a problem from the
reset-signal point of view?

[...]

Kind regards
Uffe