linux-kernel - Re: [PATCH v7] regulator: fixed: Convert to use GPIO descriptor only

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Message-ID: <c2726f18-f0cd-0d3d-c950-3e7212efd34d@nvidia.com>
Date:   Thu, 11 Oct 2018 16:00:20 +0100
From:   Jon Hunter <jonathanh@...dia.com>
To:     Linus Walleij <linus.walleij@...aro.org>,
        Marek Szyprowski <m.szyprowski@...sung.com>
CC:     Liam Girdwood <lgirdwood@...il.com>,
        Mark Brown <broonie@...nel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        Janusz Krzysztofik <jmkrzyszt@...il.com>,
        Alexander Shiyan <shc_work@...l.ru>,
        Haojian Zhuang <haojian.zhuang@...il.com>,
        Aaro Koskinen <aaro.koskinen@....fi>,
        Mike Rapoport <rppt@...ux.vnet.ibm.com>,
        Robert Jarzmik <robert.jarzmik@...e.fr>,
        Philipp Zabel <philipp.zabel@...il.com>,
        Daniel Mack <zonque@...il.com>,
        Marc Zyngier <marc.zyngier@....com>,
        jacopo <jacopo@...ndi.org>,
        Geert Uytterhoeven <geert+renesas@...der.be>,
        Russell King <rmk+kernel@...linux.org.uk>,
        linux-tegra <linux-tegra@...r.kernel.org>
Subject: Re: [PATCH v7] regulator: fixed: Convert to use GPIO descriptor only

Hi Linus,

On 11/10/18 10:29, Linus Walleij wrote:
> On Thu, Oct 11, 2018 at 11:01 AM Marek Szyprowski
> <m.szyprowski@...sung.com> wrote:
> 
>> I've just noticed that this patch causes regression on Samsung
>> Exynos4412-based Trats2 board. Conversion to GPIO descriptor breaks
>> operation when regulators used shared GPIO:  sii9234 i2c driver
>> is not able to get vcc33mhl regulator (it uses shared GPIO enable
>> line with vsil12 regulator).
> 
> So I guess this means that this physical GPIO line will enable the
> vcc33mhl and the vsil12 regulators at the same time?
> 
>> This issue has been already pointed in case of commits:
>> 37fa23dbccbd97663acc085bd79246f427e603a1
>> d1dae72fab2c377ff463742eefd8ac0f9e99b7b9
>> ab4d11e2c2329cf7cb7be31ff22489aae4dee5dc
> 
> A big sorry for my ignorance, I guess the information overload
> on the mailing list just makes me miss the important points.
> I'll try to be better, sadly I constantly fail to keep everything
> in mind and constantly break things like this.
> 
>> Maybe it would be better to first solve the handling of shared enable
>> GPIO in the descriptor-based interface before converting more regulators
>> and stepping into this issue again?
> 
> I am trying to solve it, but I just don't have systems to reproduce all
> kinds of things. It's a bit stressful since this is one of those runtime
> things that is hard to test when devising a patch for systems I don't
> have.

This also appears to be causing a regression on the Tegra124 Jetson TK1
that also uses a shared GPIO for two regulators. The 2nd regulator that
uses the GPIO now fails to probe [0] ...

[    0.680021] +5V_SATA: supplied by +5V_SYS
[    0.683964] reg-fixed-voltage: probe of regulators:regulator@14 failed with error -16

Not sure if you have one of these, but otherwise I can help test.

Cheers
Jon

[0] https://storage.kernelci.org/next/master/next-20181011/arm/tegra_defconfig/lab-baylibre-seattle/boot-tegra124-jetson-tk1.html 

-- 
nvpublic