Subject: Re: [PATCH] [RFC] qcom_scm: hide Kconfig symbol

From: Bjorn Andersson <[email-masked]>
Date: Mon, 27 Sep 2021 13:42:22 -0700

On Mon 27 Sep 13:15 PDT 2021, Arnd Bergmann wrote:

> On Mon, Sep 27, 2021 at 9:52 PM Bjorn Andersson
> <[email-masked]> wrote:
> > On Mon 27 Sep 08:22 PDT 2021, Arnd Bergmann wrote:
> > > From: Arnd Bergmann <[email-masked]>
> > >
> > >  - To avoid a circular dependency chain involving RESET_CONTROLLER
> > >    and PINCTRL_SUNXI, change the 'depends on RESET_CONTROLLER' in
> > >    the latter one to 'select'.
> >
> > Can you please help me understand why this is part of the same patch?
> 
> This can be done as a preparatory patch if we decide to do it this way,
> for the review it seemed better to spell out that this is required.
> 
> I still hope that we can avoid adding another 'select RESET_CONTROLLER'
> if someone can figure out what to do instead.
> 

Okay, thanks.

> The problem here is that QCOM_SCM selects RESET_CONTROLLER,
> and turning that into 'depends on' would in turn mean that any driver that
> wants to select QCOM_SCM would have to have the same RESET_CONTROLLER
> dependency.
> 

Right, and that will just be another thing we'll get wrong across the
tree.

> An easier option might be to find a way to build QCOM_SCM without
> RESET_CONTROLLER for compile testing purposes. I don't know
> what would break from that.
> 

Afaict the reset API is properly stubbed and RESET_CONTROLLER is a bool,
so I think we can simply drop the "select" and the kernel will still
compile fine in all combinations.

When it comes to runtime, we currently select RESET_CONTROLLER from the
Qualcomm common clocks. If that is dropped (why would it...) it seems
possible to build a custom kernel for msm8916 that we can boot and miss
the stubbed out "mss restart" reset line from the SCM.

So, let's just drop the select RESET_CONTROLLER from SCM for now.

Regards,
Bjorn