From: Douglas Anderson <dianders@chromium.org>
To: Bjorn Andersson <andersson@kernel.org>
Cc: amstan@chromium.org, swboyd@chromium.org, mka@chromium.org,
Douglas Anderson <dianders@chromium.org>,
Andy Gross <agross@kernel.org>,
Konrad Dybcio <konrad.dybcio@linaro.org>,
Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
Rob Herring <robh+dt@kernel.org>,
devicetree@vger.kernel.org, linux-arm-msm@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: [PATCH 2/2] arm64: dts: qcom: sc7280: Fix herobrine qspi pull direction
Date: Mon, 13 Feb 2023 16:57:52 -0800 [thread overview]
Message-ID: <20230213165743.2.I06f9e461a85fcd5d6fb1e977aa253f6523096b6f@changeid> (raw)
In-Reply-To: <20230213165743.1.I6f03f86546e6ce9abb1d24fd9ece663c3a5b950c@changeid>
Though it shouldn't matter very much, we've decided that it's slightly
better to park the qspi lines for herobrine with an internal pulldown
instead of an internal pullup. There is an external pulldown on one of
the data lines on the board and we don't want to have fighting pulls.
This also means that if the pulls somehow get left powered in S3
(which I'm uncertain about) that they won't be pulling up lines on an
unpowered SPI part.
Originally the pullup was picked because SPI transfers are active low
and thus the high state is somewhat more "idle", but that really isn't
that important because the chip select won't be asserted when the bus
is idle. The chip select has a nice external pullup on it that's
powered by the same power rail as the SPI flash.
This shouldn't have any functionality impact w/ reading/writing the
SPI since the lines are always push-pull when SPI transfers are
actually taking place.
Fixes: 116f7cc43d28 ("arm64: dts: qcom: sc7280: Add herobrine-r1")
Signed-off-by: Douglas Anderson <dianders@chromium.org>
---
arch/arm64/boot/dts/qcom/sc7280-herobrine.dtsi | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/arm64/boot/dts/qcom/sc7280-herobrine.dtsi b/arch/arm64/boot/dts/qcom/sc7280-herobrine.dtsi
index b6137816f2f3..7d787b12c10f 100644
--- a/arch/arm64/boot/dts/qcom/sc7280-herobrine.dtsi
+++ b/arch/arm64/boot/dts/qcom/sc7280-herobrine.dtsi
@@ -703,7 +703,7 @@ &qspi_clk {
&qspi_data01 {
/* High-Z when no transfers; nice to park the lines */
- bias-pull-up;
+ bias-pull-down;
drive-strength = <8>;
};
--
2.39.1.581.gbfd45094c4-goog
next prev parent reply other threads:[~2023-02-14 1:00 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-02-14 0:57 [PATCH 1/2] arm64: dts: qcom: sc7180: Fix trogdor qspi pull direction Douglas Anderson
2023-02-14 0:57 ` Douglas Anderson [this message]
2023-02-16 5:46 ` Stephen Boyd
2023-02-16 18:47 ` Stephen Boyd
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20230213165743.2.I06f9e461a85fcd5d6fb1e977aa253f6523096b6f@changeid \
--to=dianders@chromium.org \
--cc=agross@kernel.org \
--cc=amstan@chromium.org \
--cc=andersson@kernel.org \
--cc=devicetree@vger.kernel.org \
--cc=konrad.dybcio@linaro.org \
--cc=krzysztof.kozlowski+dt@linaro.org \
--cc=linux-arm-msm@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=mka@chromium.org \
--cc=robh+dt@kernel.org \
--cc=swboyd@chromium.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).