RE: [PATCH v6 4/4] mmc: sdhci-of-arasan: Enable UHS-1 support for Keem Bay SOC

[Zulkifli, Muhammad Husaini]

Hi Linus,

>-----Original Message-----
>From: Linus Walleij <linus.walleij@xxxxxxxxxx>
>Sent: Sunday, December 6, 2020 7:02 AM
>To: Zulkifli, Muhammad Husaini <muhammad.husaini.zulkifli@xxxxxxxxx>
>Cc: Ulf Hansson <ulf.hansson@xxxxxxxxxx>; Hunter, Adrian
><adrian.hunter@xxxxxxxxx>; Michal Simek <michal.simek@xxxxxxxxxx>; linux-
>mmc <linux-mmc@xxxxxxxxxxxxxxx>; Linux ARM <linux-arm-
>kernel@xxxxxxxxxxxxxxxxxxx>; linux-kernel@xxxxxxxxxxxxxxx; Shevchenko,
>Andriy <andriy.shevchenko@xxxxxxxxx>; Raja Subramanian, Lakshmi Bai
><lakshmi.bai.raja.subramanian@xxxxxxxxx>; Wan Mohamad, Wan Ahmad
>Zainie <wan.ahmad.zainie.wan.mohamad@xxxxxxxxx>; Mark Gross
><mgross@xxxxxxxxxxxxxxx>
>Subject: Re: [PATCH v6 4/4] mmc: sdhci-of-arasan: Enable UHS-1 support for
>Keem Bay SOC
>
>On Thu, Dec 3, 2020 at 8:10 AM Zulkifli, Muhammad Husaini
><muhammad.husaini.zulkifli@xxxxxxxxx> wrote:
>
>> >Yeah it has to be called from somewhere, if you want an abstraction
>> >to make the driver neutral to any machine, then use a selector
>> >regulator. It can be placed anywhere in the kernel as long as you can
>reference it.
>>
>> Sorry. I am not really aware of selector regulator. Can you point me
>> to any references for this?
>
>It is part of the regulator subsystem and the standard framework there to
>handle regulators with an enumerable number of specific voltage levels.
>
>> IMHO, we do not need to overengineered it to add custom selector
>> regulator just to suit this Keem Bay HW design.
>
>That can be said about a lot of things we model with vqmmc.
>Using standard abstractions makes things easier for maintainers.
>We mostly design abstractions for maintenance not for the simplest way to
>set bits in registers.

Thanks for your input. I will try model it similar to current regulator implementation
specific for keem bay SoC where this keem bay regulator will encapsulated the 
Secure Monitor Calling Convention (SMCCC) during voltage operations.

>
>Yours,
>Linus Walleij