linux-kernel - Re: [PATCH v3 2/4] arm64: dts: qcom: sc7180: revert "arm64: dts: qcom: sc7180: Avoid glitching SPI CS at bootup on trogdor"

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <CAD=FV=UriVs4-=KCg5TkzCuQaS=LEZS=CDOH0=69GsYjhPcu_g@mail.gmail.com>
Date:   Wed, 19 Oct 2022 08:48:04 -0700
From:   Doug Anderson <dianders@...omium.org>
To:     Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>
Cc:     Bjorn Andersson <andersson@...nel.org>,
        Andy Gross <agross@...nel.org>,
        Konrad Dybcio <konrad.dybcio@...ainline.org>,
        Linus Walleij <linus.walleij@...aro.org>,
        Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Matthias Kaehlcke <mka@...omium.org>,
        Stephen Boyd <swboyd@...omium.org>,
        linux-arm-msm@...r.kernel.org, linux-gpio@...r.kernel.org,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3 2/4] arm64: dts: qcom: sc7180: revert "arm64: dts:
 qcom: sc7180: Avoid glitching SPI CS at bootup on trogdor"

Hi,

On Tue, Oct 18, 2022 at 5:14 PM Krzysztof Kozlowski
<krzysztof.kozlowski@...aro.org> wrote:
>
> This reverts commit e440e30e26dd6b0424002ad0ddcbbcea783efd85 because it
> is not a reliable way of fixing SPI CS glitch and it depends on specific
> Linux kernel pin controller driver behavior.
>
> This behavior of kernel driver was changed in commit b991f8c3622c
> ("pinctrl: core: Handling pinmux and pinconf separately") thus
> effectively the DTS fix stopped being effective.
>
> Proper solution for the glitching SPI chip select must be implemented in
> the drivers, not via ordering of entries in DTS.
>
> Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>
>
> ---
>
> Changes since v2:
> 1. New patch
>
> Not tested on hardware.
>
> Cc: Doug Anderson <dianders@...omium.org>
> ---
>  arch/arm64/boot/dts/qcom/sc7180-trogdor.dtsi | 27 +++-----------------
>  1 file changed, 3 insertions(+), 24 deletions(-)

It would have been nice for the commit message to mention the fix in
the driver, which has already landed as commit d21f4b7ffc22 ("pinctrl:
qcom: Avoid glitching lines when we first mux to output").

In any case:

Reviewed-by: Douglas Anderson <dianders@...omium.org>

I've confirmed that this patch is fine after taking the pinctrl fix.

Tested-by: Douglas Anderson <dianders@...omium.org>