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Date:   Thu, 29 Jul 2021 12:32:28 +0200
From:   Maxime Ripard <maxime@cerno.tech>
To:     Icenowy Zheng <icenowy@aosc.io>
Cc:     Andre Przywara <andre.przywara@arm.com>,
        Chen-Yu Tsai <wens@csie.org>,
        Jernej Skrabec <jernej.skrabec@gmail.com>,
        Rob Herring <robh@kernel.org>,
        Samuel Holland <samuel@sholland.org>,
        linux-arm-kernel@lists.infradead.org, linux-sunxi@googlegroups.com,
        linux-sunxi@lists.linux.dev, linux-kernel@vger.kernel.org,
        Ondrej Jirman <megous@megous.com>,
        Alessandro Zummo <a.zummo@towertech.it>,
        Alexandre Belloni <alexandre.belloni@bootlin.com>,
        linux-rtc@vger.kernel.org
Subject: Re: [PATCH v7 06/19] rtc: sun6i: Add support for RTCs without
 external LOSCs
Message-ID: <20210729103228.prdav7eobi52y3ny@gilmour>
References: <20210615110636.23403-1-andre.przywara@arm.com>
 <20210615110636.23403-7-andre.przywara@arm.com>
 <20210616091431.6tm3zdf77p2x3upc@gilmour>
 <1e49692a2f4548ae942e170bc1ae9431a6eb512e.camel@aosc.io>
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On Thu, Jul 29, 2021 at 04:04:10PM +0800, Icenowy Zheng wrote:
> =E5=9C=A8 2021-06-16=E6=98=9F=E6=9C=9F=E4=B8=89=E7=9A=84 11:14 +0200=EF=
=BC=8CMaxime Ripard=E5=86=99=E9=81=93=EF=BC=9A
> > Hi,
> >=20
> > On Tue, Jun 15, 2021 at 12:06:23PM +0100, Andre Przywara wrote:
> > > Some newer Allwinner RTCs (for instance the one in the H616 SoC)
> > > lack
> > > a pin for an external 32768 Hz oscillator. As a consequence, this
> > > LOSC
> > > can't be selected as the RTC clock source, and we must rely on the
> > > internal RC oscillator.
> > > To allow additions of clocks to the RTC node, add a feature bit to
> > > ignore
> > > any provided clocks for now (the current code would think this is
> > > the
> > > external LOSC). Later DTs and code can then for instance add the
> > > PLL
> > > based clock input, and older kernel won't get confused.
> > >=20
> > > Signed-off-by: Andre Przywara <andre.przywara@arm.com>
> >=20
> > Honestly, I don't really know if it's worth it at this point.
> >=20
> > If we sums this up:
> >=20
> > =C2=A0- The RTC has 2 features that we use, mostly centered around 2
> > =C2=A0=C2=A0 registers set plus a global one
> >=20
> > =C2=A0- Those 2 features are programmed in a completely different way
> >=20
> > =C2=A0- Even the common part is different, given the discussion around =
the
> > =C2=A0=C2=A0 clocks that we have.
> >=20
> > What is there to share in that driver aside from the probe, and maybe
> > the interrupt handling? Instead of complicating this further with
> > more
> > special case that you were (rightfully) complaining about, shouldn't
> > we
> > just acknowledge the fact that it's a completely separate design and
> > should be treated as such, with a completely separate driver?
>=20
> I think our problem is just that we're having a single driver for both
> functionalities (clock manager and RTC).
>=20
> Personally I don't think we should have seperated driver for clock
> managers, although I am fine with seperated RTC driver for linear days.

Why do you think it's a bad idea to have the RTC and clocks in the same
driver?

Maxime