Re: [PATCH 00/12] soc: mediatek: pm-domains: Add new driver for SCPSYS power domains controller

From: Weiyi Lu <weiyi.lu@mediatek.com>
To: Matthias Brugger <matthias.bgg@gmail.com>
Cc: devicetree@vger.kernel.org, drinkcat@chromium.org,
	linux-kernel@vger.kernel.org, fparent@baylibre.com,
	Rob Herring <robh+dt@kernel.org>,
	linux-mediatek@lists.infradead.org, hsinyi@chromium.org,
	Enric Balletbo i Serra <enric.balletbo@collabora.com>,
	Collabora Kernel ML <kernel@collabora.com>,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH 00/12] soc: mediatek: pm-domains: Add new driver for SCPSYS power domains controller
Date: Tue, 6 Oct 2020 14:53:27 +0800	[thread overview]
Message-ID: <1601967207.8638.4.camel@mtksdaap41> (raw)
In-Reply-To: <19678952-e354-2067-e619-ffac28b347be@gmail.com>

On Fri, 2020-09-25 at 16:04 +0200, Matthias Brugger wrote:
> 
> On 25/09/2020 12:06, Weiyi Lu wrote:
> > On Thu, 2020-09-10 at 19:28 +0200, Enric Balletbo i Serra wrote:
> >> Dear all,
> >>
> >> This is a new driver with the aim to deprecate the mtk-scpsys driver.
> >> The problem with that driver is that, in order to support more Mediatek
> >> SoCs you need to add some logic to handle properly the power-up
> >> sequence of newer Mediatek SoCs, doesn't handle parent-child power
> >> domains and need to hardcode all the clocks in the driver itself. The
> >> result is that the driver is getting bigger and bigger every time a
> >> new SoC needs to be supported.
> >>
> > 
> > Hi Enric and Matthias,
> > 
> > First of all, thank you for the patch. But I'm worried the problem you
> > mentioned won't be solved even if we work on this new driver in the
> > future. My work on the MT8183 scpsys(now v17) is to implement the new
> > hardware logic. Here, I also see related patches, which means that these
> > new logics are necessary. Why can't we work on the original driver?
> 
> Well the decision was to change the driver in a not compatible way to make 
> device tree entries better. If we work on the old driver, we would need to find 
> some creative ways to handle old bindings vs new bindings.
> 
> So I thought it would be better doing a fresh start implementing mt1873 support 
> for reference and add mt8183 as new SoC. From what I have seen mt8192 and others 
> fit the driver structure too.
> 
> > Meanwhile, I thought maybe we should separate the driver into general
> > control and platform data for each SoC, otherwise it'll keep getting
> > bigger and bigger if it need to be support new SoC.
> > 
> 
> We could in a later series split the SoC depended data structures and put them 
> in drivers/soc/mediatek/pm-domains-mt8183.h or something like this. Is that what 
> you mean?
> 

Yes, that is what I want. And I guess it could avoid the collisions in
the different defines to the control registers and power status bits you
mentioned. Hope this will happen in this series.

> > And consider DVFSRC
> > (dynamic voltage and frequency scaling resource collector), should we
> > keep the original driver name "scpsys" instead of "pm-domains" because
> > it may provide more functions than power domains?
> > 
> 
> It's on my list to look deeper into this series. The thing with the new driver 
> is, that the binding takes into account, that scpsys has several hardware block, 
> which are represented as child nodes in DTS. The pm-domains is just one of these 
> functionalities and I think DVFSRC should be a new driver with a child node of 
> scpsys in DTS. Does this make sense?
> 
> Regards,
> Matthias
> 
> >> All this information can be getted from a properly defined binding, so
> >> can be cleaner and smaller, hence, we implemented a new driver. For
> >> now, only MT8173 and MT8183 is supported but should be fairly easy to
> >> add support for new SoCs.
> >>
> >> Best regards,
> >>    Enric
> >>
> >> Enric Balletbo i Serra (4):
> >>    dt-bindings: power: Add bindings for the Mediatek SCPSYS power domains
> >>      controller
> >>    soc: mediatek: Add MediaTek SCPSYS power domains
> >>    arm64: dts: mediatek: Add mt8173 power domain controller
> >>    dt-bindings: power: Add MT8183 power domains
> >>
> >> Matthias Brugger (8):
> >>    soc: mediatek: pm-domains: Add bus protection protocol
> >>    soc: mediatek: pm_domains: Make bus protection generic
> >>    soc: mediatek: pm-domains: Add SMI block as bus protection block
> >>    soc: mediatek: pm-domains: Add extra sram control
> >>    soc: mediatek: pm-domains: Add subsystem clocks
> >>    soc: mediatek: pm-domains: Allow bus protection to ignore clear ack
> >>    soc: mediatek: pm-domains: Add support for mt8183
> >>    arm64: dts: mediatek: Add mt8183 power domains controller
> >>
> >>   .../power/mediatek,power-controller.yaml      | 173 ++++
> >>   arch/arm64/boot/dts/mediatek/mt8173.dtsi      |  78 +-
> >>   arch/arm64/boot/dts/mediatek/mt8183.dtsi      | 160 +++
> >>   drivers/soc/mediatek/Kconfig                  |  13 +
> >>   drivers/soc/mediatek/Makefile                 |   1 +
> >>   drivers/soc/mediatek/mtk-infracfg.c           |   5 -
> >>   drivers/soc/mediatek/mtk-pm-domains.c         | 952 ++++++++++++++++++
> >>   include/dt-bindings/power/mt8183-power.h      |  26 +
> >>   include/linux/soc/mediatek/infracfg.h         |  39 +
> >>   9 files changed, 1433 insertions(+), 14 deletions(-)
> >>   create mode 100644 Documentation/devicetree/bindings/power/mediatek,power-controller.yaml
> >>   create mode 100644 drivers/soc/mediatek/mtk-pm-domains.c
> >>   create mode 100644 include/dt-bindings/power/mt8183-power.h
> >>
> > 
> 
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