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

From: Jon Hunter
Date: Thu Oct 11 2018 - 11:00:29 EST

Hi Linus,

On 11/10/18 10:29, Linus Walleij wrote:
> On Thu, Oct 11, 2018 at 11:01 AM Marek Szyprowski
> <m.szyprowski@xxxxxxxxxxx> 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.