linux-kernel - Re: [PATCH v1 1/2] mfd: mt6397: Add new bit definitions for RTC

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Message-ID: <272b601e803474ad1048f1957142a234f03892af.camel@mediatek.com>
Date: Tue, 19 Aug 2025 07:53:34 +0000
From: Shunxi Zhang (章顺喜)
	<ot_shunxi.zhang@...iatek.com>
To: "giorgitchankvetadze1997@...il.com" <giorgitchankvetadze1997@...il.com>,
	"krzk@...nel.org" <krzk@...nel.org>
CC: "linux-mediatek@...ts.infradead.org" <linux-mediatek@...ts.infradead.org>,
	Eddie Huang (黃智傑) <eddie.huang@...iatek.com>,
	"alexandre.belloni@...tlin.com" <alexandre.belloni@...tlin.com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	Jh Hsu (許希孜) <Jh.Hsu@...iatek.com>,
	Vince-WL Liu (劉文龍) <Vince-WL.Liu@...iatek.com>,
	Sean Wang <Sean.Wang@...iatek.com>, "linux-arm-kernel@...ts.infradead.org"
	<linux-arm-kernel@...ts.infradead.org>, "lee@...nel.org" <lee@...nel.org>,
	"matthias.bgg@...il.com" <matthias.bgg@...il.com>,
	"linux-rtc@...r.kernel.org" <linux-rtc@...r.kernel.org>,
	Sirius Wang (王皓昱) <Sirius.Wang@...iatek.com>
Subject: Re: [PATCH v1 1/2] mfd: mt6397: Add new bit definitions for RTC_BBPU
 register

On Mon, 2025-08-11 at 15:21 +0400, Giorgi Tchankvetadze wrote:
> External email : Please do not click links or open attachments until
> you have verified the sender or the content.
> 
> 
> Cc: Krzysztof Kozlowski <krzk@...nel.org>,
>     linux-mediatek@...ts.infradead.org,
>     linux-rtc@...r.kernel.org,
>     linux-kernel@...r.kernel.org
> 
> Shunxi,
> 
> Can you confirm whether `RTC_BBPU_PWREN` (bit 0),
> `RTC_BBPU_CLR` (bit 1) and `RTC_BBPU_RESET_AL` (bit 3) are documented
> in the MT6397 datasheet (please cite section/page)? They look like
> standard RTC controls (power enable, clear/reset, alarm reset) and
> might be useful to include, but I agree with Krzysztof that adding
> definitions with no users can accumulate technical debt.
> 
> Suggestion: either
> - add the definitions when a driver actually needs them, or
> - keep them now but add a short rationale in the commit message
>   (datasheet reference + intended use) so future reviewers understand
>   why they exist.
> 
> Also: please split cosmetic whitespace fixes (RTC_BBPU_KEY) into a
> separate patch to make review/merge easier.
> 
> Thanks for the patch; I’m following the thread.
> 
> — Giorgi

Dear sir,
The MT6397 is an integration of several ICs and does not have a
separate IC specification. I will check the relevant IC datasheets
again. I will remove the useless define in next version.

Thanks for your commnets.

Best regards
Shunxi Zhangus
> 
> 
> On Mon, Aug 11, 2025 at 3:03 PM Krzysztof Kozlowski <krzk@...nel.org>
> wrote:
> > 
> > On 11/08/2025 10:15, ot_shunxi.zhang@...iatek.com wrote:
> > > From: Shunxi Zhang <ot_shunxi.zhang@...iatek.com>
> > > 
> > > This patch adds new bit definitions for the RTC_BBPU register in
> > > the
> > 
> > Why? There is no user of these. Don't add useless defines.
> > 
> > > mt6397 RTC header file. The following bit definitions are
> > > introduced:
> > 
> > Hm?
> > 
> > > 
> > > Signed-off-by: Shunxi Zhang <ot_shunxi.zhang@...iatek.com>
> > > ---
> > >  include/linux/mfd/mt6397/rtc.h | 5 ++++-
> > >  1 file changed, 4 insertions(+), 1 deletion(-)
> > > 
> > > diff --git a/include/linux/mfd/mt6397/rtc.h
> > > b/include/linux/mfd/mt6397/rtc.h
> > > index 27883af44f87..001cef6b7302 100644
> > > --- a/include/linux/mfd/mt6397/rtc.h
> > > +++ b/include/linux/mfd/mt6397/rtc.h
> > > @@ -15,8 +15,11 @@
> > >  #include <linux/rtc.h>
> > > 
> > >  #define RTC_BBPU               0x0000
> > > +#define RTC_BBPU_PWREN         BIT(0)
> > > +#define RTC_BBPU_CLR           BIT(1)
> > > +#define RTC_BBPU_RESET_AL      BIT(3)
> > >  #define RTC_BBPU_CBUSY         BIT(6)
> > > -#define RTC_BBPU_KEY            (0x43 << 8)
> > > +#define RTC_BBPU_KEY           (0x43 << 8)
> > 
> > 
> > Why?
> > 
> > 
> > 
> > Best regards,
> > Krzysztof
> >