linux-kernel - Re: [PATCH v5 0/1] dt-bindings: riscv: sophgo: add RTC for CV1800

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Date: Mon, 8 Jan 2024 17:00:47 +0800
From: Jingbao Qiu <qiujingbao.dlmu@...il.com>
To: Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>
Cc: a.zummo@...ertech.it, 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
Subject: Re: [PATCH v5 0/1] dt-bindings: riscv: sophgo: add RTC for CV1800

On Mon, Jan 8, 2024 at 4:02 PM Krzysztof Kozlowski
<krzysztof.kozlowski@...aro.org> wrote:
>
> On 08/01/2024 08:22, Jingbao Qiu wrote:
> > Real Time Clock (RTC) is an independently powered module
> > within the chip, which includes a 32KHz oscillator and
> > a Power On Reset/POR submodule. It can be used for time
> > display and timed alarm generation.
> >
> > Power On Reset/POR submodule only using register resources
> > so it should be empty. The 32KHz oscillator only provides
> > pulses for RTC in hardware.
> >
> >
> > Changes since v4:
> > - remove POR dt-bindings because it empty
> > - remove MFD dt-bindings because SoC does
> >   not have MFDs
> > - add syscon attribute to share registers
> >   with POR
> >
> > v4: https://lore.kernel.org/all/20231229090643.116575-1-qiujingbao.dlmu@gmail.com/
> >
> > Changes since v3:
> > - temporarily not submitting RTC driver code
> >   waiting for communication with IC designer
>
> Hm, why?
>
> We do not need bindings if nothing matches to them. If this binding is
> for other upstream open-source project, please provide references.
>
> See also:
> https://elixir.bootlin.com/linux/v6.7-rc8/source/Documentation/devicetree/bindings/submitting-patches.rst#L61
>

Hi!

There is a function in the RTC driver code used to calibrate the
clock, which is define in the datasheet.
However, Alexandre Belloni raised concerns that clock calibration
should be done using GPS or similar
methods, rather than using other clock sources. I think what he said
makes sense. So it is necessary
to communicate with IC designers.

link: https://lore.kernel.org/all/202312271350242a208426@mail.local/

Best regards,
Jingbao Qiu