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From: Jingbao Qiu <qiujingbao.dlmu@gmail.com>
Date: Wed, 17 Jan 2024 18:12:17 +0800
Message-ID: <CAJRtX8QJsVGfTTBSsZu0p8Q_TWG6zBK82S5BQQi_Cn7S4dBXVw@mail.gmail.com>
Subject: Re: [PATCH v6 3/3] riscv: dts: sophgo: add rtc dt node for CV1800
To: Alexandre Belloni <alexandre.belloni@bootlin.com>
Cc: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>, robh+dt@kernel.org, 
	krzysztof.kozlowski+dt@linaro.org, conor+dt@kernel.org, chao.wei@sophgo.com, 
	unicorn_wang@outlook.com, paul.walmsley@sifive.com, palmer@dabbelt.com, 
	aou@eecs.berkeley.edu, linux-rtc@vger.kernel.org, devicetree@vger.kernel.org, 
	linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org, 
	dlan@gentoo.org, inochiama@outlook.com
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On Wed, Jan 17, 2024 at 5:01=E2=80=AFPM Alexandre Belloni
<alexandre.belloni@bootlin.com> wrote:
>
> On 17/01/2024 10:54:08+0800, Jingbao Qiu wrote:
> > On Wed, Jan 17, 2024 at 12:53=E2=80=AFAM Alexandre Belloni
> > <alexandre.belloni@bootlin.com> wrote:
> > >
> > > On 17/01/2024 00:29:28+0800, Jingbao Qiu wrote:
> > > > On Wed, Jan 17, 2024 at 12:03=E2=80=AFAM Krzysztof Kozlowski
> > > > <krzysztof.kozlowski@linaro.org> wrote:
> > > > >
> > > > > On 16/01/2024 16:51, Jingbao Qiu wrote:
> > > > > >>> CV1800 is a RISCV based SOC that includes an RTC module. The =
RTC
> > > > > >>> module has an OSC oscillator
> > > > > >>
> > > > > >>
> > > > > >> I am not going to read pages of description. Please write conc=
ise replies.
> > > > > >
> > > > > > Thanks, What I mean is that this hardware includes two function=
s, RTC
> > > > > > and POR. How should I describe their relationship?
> > > > >
> > > > > Your POR does not need to take any resources, so no need to descr=
ibe any
> > > > > relationship.
> > > > >
> > > > > ...
> > > > >
> > > > > >>> Your suggestion is, firstly, the por submodule does not have =
any
> > > > > >>> resources, so it should be deleted.
> > > > > >>
> > > > > >> So where did you delete it? I still see it in this patch.
> > > > > >
> > > > > > Should I completely delete him? How can a por driver obtain dev=
ice information?
> > > > >
> > > > > Delete completely.
> > > > >
> > > > > Device information? What is this? We already agreed you don't hav=
e any
> > > > > resources for POR.
> > > > >
> > > > > ....
> > > > >
> > > > > >> Device is only one thing, not two.
> > > > > >>
> > > > > >>>                     reg =3D <0x5025000 0x2000>;
> > > > > >>>                     interrupts =3D <17 IRQ_TYPE_LEVEL_HIGH>;
> > > > > >>>                     clocks =3D <&osc>;
> > > > > >>> };
> > > > > >>> However, in reality, the POR submodule does not use IRQ and C=
LK.
> > > > > >>> Please do not hesitate to teach. Thanks.
> > > > > >>
> > > > > >> I expect one device node. How many drivers you have does not m=
atter: you
> > > > > >> can instantiate 100 Linux devices in 100 Linux device drivers.
> > > > > >
> > > > > > I understand what you mean. A device node corresponds to multip=
le drivers.
> > > > > > Should I completely delete the POR device tree node and add it =
when
> > > > > > submitting the POR driver?
> > > > >
> > > > > ? I wrote it in previous messages and twice in this thread. Compl=
etely
> > > > > delete. You do not add it back! Because if you ever intended to a=
dd it
> > > > > back, it should be added since beginning. I don't understand what
> > > > > submitting later would solve.
> > > > >
> > > > > > If that's the case, how can I explain that the rtc device tree =
node
> > > > > > uses the syscon tag?
> > > > > > How can I describe a POR device in DTS? POR is a submodule of R=
TC, and
> > > > > > it also has corresponding drivers.
> > > > >
> > > > > I said, there is no need for POR in DTS, because you have nothing=
 there.
> > > > > Why do you insist on putting it on DTS?
> > > > >
> > > > > > It's just that his resources are only shared with RTC's Reg.
> > > > >
> > > > > What resources? Reg? That's not a separate resource.
> > > >
> > > > I'm very sorry about this.
> > > > But I found a binding file that only contains Reg and Compatible.
> > > >
> > > > rtc@80920000 {
> > > > compatible =3D "cirrus,ep9301-rtc";
> > > > reg =3D <0x80920000 0x100>;
> > > > };
> > > >
> > > > Link: Documentation/devicetree/bindings/rtc/cirrus,ep9301-rtc.yaml
> > > >
> > > > >
> > > > > To summarize: Drop POR from DTS and never bring it back, unless y=
ou come
> > > > > with some different arguments, which you did not say already.
> > > > >
> > > >
> > > > You are right, if there is no por device tree node, how can the por
> > > > driver obtain the Reg?
> > >
> > > I guess the question is why don't you register everything from the RT=
C
> > > driver?
> >
> > Thanks, POR provides power off and restart functions as a child node of=
 RTC.
> > So, I think it should be placed in the power/reset directory.
>
> No it doesn't, have a look at the jz4740 rtc driver

Thank you for your suggestion.

Best regards,
Jingbao Qiu