Re: [PATCH linux] aspeed: pinctrl: Allow disabling Port D and Port E loopback mode

From	Linus Walleij <linus.walleij@linaro.org>
Newsgroups	linux.kernel
Subject	Re: [PATCH linux] aspeed: pinctrl: Allow disabling Port D and Port E loopback mode
Date	2017-02-23 15:50 +0100
Message-ID	<te2Su-2AJ-9@gated-at.bofh.it> (permalink)
References	<tb0WR-4oq-1@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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On Wed, Feb 15, 2017 at 7:09 AM, Rick Altherr <raltherr@google.com> wrote:

> Port D and port E GPIO loopback modes are commonly enabled via hardware
> straps for use with front-panel buttons.  When the BMC is powered
> off or fails to boot, the front-panel buttons are directly connected to
> the host chipset via the loopback to allow direct power-on and reset
> control. Once the BMC has booted, the loopback mode must be disabled for
> the BMC to take over control of host power-on and reset.
>
> Disabling these loopback modes requires writing to the hardware strap
> register which violates the current design of assuming the system
> designer chose the strap settings for a specific reason and they should
> be treated as read-only. Only the two bits of the strap register related
> to these loopback modes are allowed to be written and comments have been
> added to explain why.
>
> Signed-off-by: Rick Altherr <raltherr@google.com>

Patch applied with the ACKs for v4.12.

Yours,
Linus Walleij

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[PATCH linux] aspeed: pinctrl: Allow disabling Port D and Port E loopback mode Rick Altherr <raltherr@google.com> - 2017-02-15 07:10 +0100
  Re: [PATCH linux] aspeed: pinctrl: Allow disabling Port D and Port E  loopback mode Linus Walleij <linus.walleij@linaro.org> - 2017-02-23 15:50 +0100

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