From: Andy Shevchenko <andy.shevchenko@gmail.com>
To: Ulf Hansson <ulf.hansson@linaro.org>
Cc: "Shevchenko, Andriy" <andriy.shevchenko@intel.com>,
Linus Walleij <linus.walleij@linaro.org>,
"Zulkifli,
Muhammad Husaini" <muhammad.husaini.zulkifli@intel.com>,
Adrian Hunter <adrian.hunter@intel.com>,
Michal Simek <michal.simek@xilinx.com>,
"linux-mmc@vger.kernel.org" <linux-mmc@vger.kernel.org>,
Linux ARM <linux-arm-kernel@lists.infradead.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
"Raja Subramanian,
Lakshmi Bai" <lakshmi.bai.raja.subramanian@intel.com>,
Wan Ahmad Zainie <wan.ahmad.zainie.wan.mohamad@intel.com>,
Mark Gross <mgross@linux.intel.com>
Subject: Re: [PATCH v6 0/4] mmc: sdhci-of-arasan: Enable UHS-1 support for Keem Bay SOC
Date: Wed, 2 Dec 2020 16:34:44 +0200 [thread overview]
Message-ID: <CAHp75Vf66eWnJFom66oZZnZ4Rcw0VF0QkGWgM5Mm40mTVt6i4A@mail.gmail.com> (raw)
In-Reply-To: <CAPDyKFpfadG2-JPA1PC5Sx1_eM39AQUQTVj=m26Gu_=GQmjicA@mail.gmail.com>
On Wed, Dec 2, 2020 at 4:10 PM Ulf Hansson <ulf.hansson@linaro.org> wrote:
> On Wed, 2 Dec 2020 at 14:09, Andy Shevchenko <andy.shevchenko@gmail.com> wrote:
> > On Wed, Dec 2, 2020 at 2:44 PM Ulf Hansson <ulf.hansson@linaro.org> wrote:
...
> > My point is that it may be *not* a pin control at all.
>
> Sorry, but I don't quite follow, what is *not* a pinctrl?
>
> According to the information I have received from the previous
> discussions [1], it's clear to me that the ARM SMC call ends up
> changing settings for the I/O-pads. Or did I get that wrong?
I'm discussing the possible implication of the solution (faking pin
control) you are proposing.
In this case we know that it's a pin control *under the hood of IPC*
(!) but in another hardware generation it may be, for example,custom
voltage regulator.
What you are proposing seems to me suboptimal and actually lying about
hardware. Because we do not have direct access to control this pad.
What we have is an IPC to firmware. And it's not our business what is
under the hood.
It seems it was a mistake to talk about these details in the first
place because it brings more confusion about hardware. So, consider
that it's not a pin control from OS perspective, but a firmware magic.
--
With Best Regards,
Andy Shevchenko
WARNING: multiple messages have this Message-ID (diff)
From: Andy Shevchenko <andy.shevchenko@gmail.com>
To: Ulf Hansson <ulf.hansson@linaro.org>
Cc: Mark Gross <mgross@linux.intel.com>,
"Shevchenko, Andriy" <andriy.shevchenko@intel.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Linus Walleij <linus.walleij@linaro.org>,
"linux-mmc@vger.kernel.org" <linux-mmc@vger.kernel.org>,
Michal Simek <michal.simek@xilinx.com>,
Adrian Hunter <adrian.hunter@intel.com>,
Wan Ahmad Zainie <wan.ahmad.zainie.wan.mohamad@intel.com>,
"Raja Subramanian,
Lakshmi Bai" <lakshmi.bai.raja.subramanian@intel.com>,
"Zulkifli,
Muhammad Husaini" <muhammad.husaini.zulkifli@intel.com>,
Linux ARM <linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH v6 0/4] mmc: sdhci-of-arasan: Enable UHS-1 support for Keem Bay SOC
Date: Wed, 2 Dec 2020 16:34:44 +0200 [thread overview]
Message-ID: <CAHp75Vf66eWnJFom66oZZnZ4Rcw0VF0QkGWgM5Mm40mTVt6i4A@mail.gmail.com> (raw)
In-Reply-To: <CAPDyKFpfadG2-JPA1PC5Sx1_eM39AQUQTVj=m26Gu_=GQmjicA@mail.gmail.com>
On Wed, Dec 2, 2020 at 4:10 PM Ulf Hansson <ulf.hansson@linaro.org> wrote:
> On Wed, 2 Dec 2020 at 14:09, Andy Shevchenko <andy.shevchenko@gmail.com> wrote:
> > On Wed, Dec 2, 2020 at 2:44 PM Ulf Hansson <ulf.hansson@linaro.org> wrote:
...
> > My point is that it may be *not* a pin control at all.
>
> Sorry, but I don't quite follow, what is *not* a pinctrl?
>
> According to the information I have received from the previous
> discussions [1], it's clear to me that the ARM SMC call ends up
> changing settings for the I/O-pads. Or did I get that wrong?
I'm discussing the possible implication of the solution (faking pin
control) you are proposing.
In this case we know that it's a pin control *under the hood of IPC*
(!) but in another hardware generation it may be, for example,custom
voltage regulator.
What you are proposing seems to me suboptimal and actually lying about
hardware. Because we do not have direct access to control this pad.
What we have is an IPC to firmware. And it's not our business what is
under the hood.
It seems it was a mistake to talk about these details in the first
place because it brings more confusion about hardware. So, consider
that it's not a pin control from OS perspective, but a firmware magic.
--
With Best Regards,
Andy Shevchenko
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2020-12-02 14:34 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-02 15:02 [PATCH v6 0/4] mmc: sdhci-of-arasan: Enable UHS-1 support for Keem Bay SOC muhammad.husaini.zulkifli
2020-12-02 15:02 ` muhammad.husaini.zulkifli
2020-12-02 10:53 ` Ulf Hansson
2020-12-02 10:53 ` Ulf Hansson
2020-12-02 12:25 ` Shevchenko, Andriy
2020-12-02 12:25 ` Shevchenko, Andriy
2020-12-02 12:41 ` Ulf Hansson
2020-12-02 12:41 ` Ulf Hansson
2020-12-02 13:10 ` Andy Shevchenko
2020-12-02 13:10 ` Andy Shevchenko
2020-12-02 14:10 ` Ulf Hansson
2020-12-02 14:10 ` Ulf Hansson
2020-12-02 14:34 ` Andy Shevchenko [this message]
2020-12-02 14:34 ` Andy Shevchenko
2020-12-02 14:38 ` Zulkifli, Muhammad Husaini
2020-12-02 14:38 ` Zulkifli, Muhammad Husaini
2020-12-02 15:02 ` [PATCH v6 1/4] mmc: sdhci-of-arasan: Add structure device pointer in probe func muhammad.husaini.zulkifli
2020-12-02 15:02 ` muhammad.husaini.zulkifli
2020-12-02 15:02 ` [PATCH v6 2/4] firmware: keembay: Add support for Trusted Firmware Service call muhammad.husaini.zulkifli
2020-12-02 15:02 ` muhammad.husaini.zulkifli
2020-12-02 15:02 ` [PATCH v6 3/4] dt-bindings: mmc: Add phys, vmmc and vqmmc supplies for Keem Bay SOC muhammad.husaini.zulkifli
2020-12-02 15:02 ` muhammad.husaini.zulkifli
2020-12-02 15:02 ` [PATCH v6 4/4] mmc: sdhci-of-arasan: Enable UHS-1 support " muhammad.husaini.zulkifli
2020-12-02 15:02 ` muhammad.husaini.zulkifli
2020-12-02 18:54 ` Linus Walleij
2020-12-02 18:54 ` Linus Walleij
2020-12-03 7:10 ` Zulkifli, Muhammad Husaini
2020-12-03 7:10 ` Zulkifli, Muhammad Husaini
2020-12-03 8:12 ` Shevchenko, Andriy
2020-12-03 8:12 ` Shevchenko, Andriy
2020-12-05 23:01 ` Linus Walleij
2020-12-05 23:01 ` Linus Walleij
2020-12-12 14:06 ` Zulkifli, Muhammad Husaini
2020-12-12 14:06 ` Zulkifli, Muhammad Husaini
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