From: Doug Anderson <dianders@chromium.org>
To: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Cc: Bjorn Andersson <andersson@kernel.org>,
Andy Gross <agross@kernel.org>,
Konrad Dybcio <konrad.dybcio@somainline.org>,
Linus Walleij <linus.walleij@linaro.org>,
Rob Herring <robh+dt@kernel.org>,
Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
Matthias Kaehlcke <mka@chromium.org>,
Stephen Boyd <swboyd@chromium.org>,
linux-arm-msm@vger.kernel.org, linux-gpio@vger.kernel.org,
devicetree@vger.kernel.org, linux-kernel@vger.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"
Date: Wed, 19 Oct 2022 08:48:04 -0700 [thread overview]
Message-ID: <CAD=FV=UriVs4-=KCg5TkzCuQaS=LEZS=CDOH0=69GsYjhPcu_g@mail.gmail.com> (raw)
In-Reply-To: <20221019001351.1630089-3-krzysztof.kozlowski@linaro.org>
Hi,
On Tue, Oct 18, 2022 at 5:14 PM Krzysztof Kozlowski
<krzysztof.kozlowski@linaro.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@linaro.org>
>
> ---
>
> Changes since v2:
> 1. New patch
>
> Not tested on hardware.
>
> Cc: Doug Anderson <dianders@chromium.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@chromium.org>
I've confirmed that this patch is fine after taking the pinctrl fix.
Tested-by: Douglas Anderson <dianders@chromium.org>
next prev parent reply other threads:[~2022-10-19 15:53 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-10-19 0:13 [PATCH v3 0/4] arm64/pinctrl: dt-bindings: qcom: sc7180: convert to dtschema Krzysztof Kozlowski
2022-10-19 0:13 ` [PATCH v3 1/4] arm64: dts: qcom: sc7180-trogdor-homestar: fully configure secondary I2S pins Krzysztof Kozlowski
2022-10-19 0:13 ` [PATCH v3 2/4] arm64: dts: qcom: sc7180: revert "arm64: dts: qcom: sc7180: Avoid glitching SPI CS at bootup on trogdor" Krzysztof Kozlowski
2022-10-19 15:48 ` Doug Anderson [this message]
2022-10-20 22:44 ` Krzysztof Kozlowski
2022-10-19 0:13 ` [PATCH v3 3/4] arm64: dts: qcom: sc7180: align TLMM pin configuration with DT schema Krzysztof Kozlowski
2022-10-19 15:48 ` Doug Anderson
2022-10-20 22:44 ` Krzysztof Kozlowski
2022-10-19 0:13 ` [PATCH v3 4/4] dt-bindings: pinctrl: qcom,sc7180: convert to dtschema Krzysztof Kozlowski
2022-10-19 15:41 ` (subset) " Krzysztof Kozlowski
2022-10-19 15:48 ` Doug Anderson
2022-10-19 15:57 ` Krzysztof Kozlowski
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