linux-kernel - Re: [PATCH v1 0/7] imx-gpcv2 improvements

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Message-ID: <CAHCN7xK=mjvgrMGXfFwN6520rhtdZu9YRiSn6mi6-+9sVA-LWg@mail.gmail.com>
Date:   Fri, 9 Apr 2021 08:36:29 -0500
From:   Adam Ford <aford173@...il.com>
To:     "Peng Fan (OSS)" <peng.fan@....nxp.com>
Cc:     Lucas Stach <l.stach@...gutronix.de>,
        Adrien Grassein <adrien.grassein@...il.com>,
        Rob Herring <robh+dt@...nel.org>,
        Shawn Guo <shawnguo@...nel.org>,
        Sascha Hauer <s.hauer@...gutronix.de>,
        Sascha Hauer <kernel@...gutronix.de>,
        Fabio Estevam <festevam@...il.com>,
        NXP Linux Team <linux-imx@....com>,
        Anson Huang <Anson.Huang@....com>,
        Krzysztof Kozlowski <krzk@...nel.org>,
        Peng Fan <peng.fan@....com>,
        Aisheng Dong <aisheng.dong@....com>, qiangqing.zhang@....com,
        Alice Guo <alice.guo@....com>,
        Guido Günther <agx@...xcpu.org>,
        Andrey Smirnov <andrew.smirnov@...il.com>,
        devicetree <devicetree@...r.kernel.org>,
        arm-soc <linux-arm-kernel@...ts.infradead.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v1 0/7] imx-gpcv2 improvements

On Wed, Apr 7, 2021 at 8:27 PM Peng Fan (OSS) <peng.fan@....nxp.com> wrote:
>
> Hi Lucas,
>
> On 2021/4/8 6:13, Lucas Stach wrote:
> > Hi Adrien,
> >
> > I feel like I already mentioned to you some time ago that there is
> > already a much more complete patch series to add this functionality on
> > the list [1].
> >
> > If you want this functionality to go upstream, please help test and
> > extend this patch series.
> >
> > Regards,
> > Lucas
> >
> > [1] https://lore.kernel.org/linux-arm-kernel/20201105174434.1817539-1-l.stach@pengutronix.de/
>
> Would you share what's the issue that block this going forward?

Peng,

I know of a few.  One of them is mentioned in [1] above.  From what I
can tell, the dt-bindings have halted being able to enable the GPU and
USB power domains.  See [2] for some of that dialog.

The second part that I am aware is the blk-ctl being dependent on the
power domain and the power domain being dependent on the blk-ctl [3]
There was some discussion of using syscon to let the power-domain
finish coming up and then referencing the the power-domain from the
blk-ctl, but there was some disagreement [4] on that approach

I think Abel tried to create an IRC, but by the time I was able to
join the IRC, there was no activity.

[2] - https://lore.kernel.org/linux-arm-kernel/CAHCN7xLdkEd0G3fa9gAp-xvKZ-bYmvcyn-8OEbgNjBJyCCOs9g@mail.gmail.com/
[3] - https://lkml.org/lkml/2020/11/9/17
[4] - https://www.spinics.net/lists/arm-kernel/msg849032.html

>
> Thanks,
> Peng.
>
> >
> > Am Mittwoch, dem 07.04.2021 um 23:21 +0200 schrieb Adrien Grassein:
> >> Hi,
> >>
> >> This patch set aims is to add the support of the i.MX8 MM power domains
> >> on the mainline kernel.
> >>
> >> To achieve this, I do several patches
> >>    - Check errors when reading or writing registers (concerns i.MX8M base
> >>      implementation);
> >>    - Fix power up/down sequence. Handshake was not checked and it was
> >>      not called at the appropriate time (concerns i.MX8M base
> >> implementaions);
> >>    - Allow domains without power sequence control like the HSIOMIX of the
> >>      i.MX8MM.
> >>    - Add some i.MX8MM domains (HSIO and OTGS);
> >>    - Introduce quirks. For example, i.MX8MM OTG domains should not be
> >>      powered off (seen n the source code of th i.MX ATF). Quirks are
> >> easily upgrable for other cases.
> >>    - Finally I defined power domains into the imx8mm.dtb file.
> >>
> >> I know that this kind of patch is rejected by NXP ut the other way
> >> (callin ATF directly) was also rejected.
> >>
> >> I also know that NXP is concerned abou adding hundred lines of codes for
> >> each new SOC but it' the way it works on Linux. And the "added code"
> >> mainly consist of adding structures, defines and generic methods for
> >> regmap.
> >>
> >> If it's a real problem, maybe we can introduc a new "gpcv3" driver for
> >> i.MX8MM, i.MX8MN and i.MX8MP.
> >>
> >> Thanks,
> >>
> >> Adrien Grassein (7):
> >>    soc: imx: gpcv2: check for errors when r/w registers
> >>    soc: imx: gpcv2: Fix power up/down sequence
> >>    soc: imx: gpcv2: allow domains without power sequence control
> >>    dt-bindings: power: fsl,imx-gpcv2: add definitions for i.MX8MM
> >>    soc: imx: gpcv2: add HSIOMIX and USB domains for i.MX8MM
> >>    soc: imx: gpcv2: add quirks to domains
> >>    arm64: dts: imx8mm: add power-domains
> >>
> >>   .../bindings/power/fsl,imx-gpcv2.yaml         |   7 +-
> >>   arch/arm64/boot/dts/freescale/imx8mm.dtsi     |  35 ++
> >>   drivers/soc/imx/gpcv2.c                       | 336 ++++++++++++++----
> >>   include/dt-bindings/power/imx8mm-power.h      |  21 ++
> >>   4 files changed, 333 insertions(+), 66 deletions(-)
> >>   create mode 100644 include/dt-bindings/power/imx8mm-power.h
> >>
> >
> >