linux-kernel - Re: [PATCH v8 2/2] rtc: sophgo: add rtc support for Sophgo CV1800 SoC

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Message-ID: <CAJRtX8Ruh4BethYcGM2RueNBDioXpn8dJ3yvUD4iW_1cmiVFqg@mail.gmail.com>
Date: Wed, 1 May 2024 17:14:43 +0800
From: Jingbao Qiu <qiujingbao.dlmu@...il.com>
To: Inochi Amaoto <inochiama@...look.com>
Cc: alexandre.belloni@...tlin.com, robh+dt@...nel.org, 
	krzysztof.kozlowski+dt@...aro.org, conor+dt@...nel.org, 
	paul.walmsley@...ive.com, palmer@...belt.com, aou@...s.berkeley.edu, 
	linux-rtc@...r.kernel.org, devicetree@...r.kernel.org, 
	linux-kernel@...r.kernel.org, dlan@...too.org
Subject: Re: [PATCH v8 2/2] rtc: sophgo: add rtc support for Sophgo CV1800 SoC

On Wed, May 1, 2024 at 3:43 PM Inochi Amaoto <inochiama@...look.com> wrote:
>
> On Wed, May 01, 2024 at 01:03:58PM GMT, Jingbao Qiu wrote:
> > Hi, Inochi
> >
> > On Wed, May 1, 2024 at 10:19 AM Inochi Amaoto <inochiama@...look.com> wrote:

> > > Another thing is that I do not think is a good way to let the
> > > rtc driver access RTC_CTRL area directly. You have already
> > > know there is a 8051 device in the 0x05025000. It is necessary
> > > to make some room for this device. Maybe you want to implement
> > > them all in the rtc driver? If so, I do think it is a bad idea.
> >
> >
> > Do you mean that RTC drivers should not directly access the 0x05025000 address?
> > Because there is an 8051 subsystem on this address.
>
> Yes. At least we need some mechanism to share these address between
> this devices.
>
> > Firstly, I do not intend to implement 8051 in the RTC driver,
> > but the 8051 subsystem is located within a module independently
> > powered by the RTC.
> > So if we want to implement the 8051 subsystem in the future, it can be
> > used as a node in RTC? I'm not sure.
>
> Yes, this is what I care about.
>
> > Then, Alexandre told me that there are operations related to PM in
> > RTC, such as the following files.
> > This matches the description of address 0x05025000.
> >
> > drivers/rtc/rtc jz4740. c
> >
>
> I do not think this is something related to the PM. 8051 is more
> like remoteproc. So it is necessary to arrange them carefully.
>

You are right.
I learned from official documents that 8051 works in the RTC domain.
Linux does not provide relevant interfaces to operate 8051,
Just providing a mailbox for communication between them, or through
interruptions.
I don't understand how 8051 works, so I shouldn't write to the
corresponding registers in RTC.

https://milkv.io/docs/duo/getting-started/8051core


> > > > 2.25.1
> > > >