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Message-Id: <20240326-rk-default-enable-strobe-pulldown-v1-0-f410c71605c0@folker-schwesinger.de>
Date: Tue, 26 Mar 2024 19:54:34 +0100
From: Folker Schwesinger via B4 Relay <devnull+dev.folker-schwesinger.de@...nel.org>
To: Vinod Koul <vkoul@...nel.org>,
Kishon Vijay Abraham I <kishon@...nel.org>,
Heiko Stuebner <heiko@...ech.de>, Chris Ruehl <chris.ruehl@...ys.com.hk>,
Rob Herring <robh@...nel.org>,
Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
Conor Dooley <conor+dt@...nel.org>
Cc: Christopher Obbard <chris.obbard@...labora.com>,
Alban Browaeys <alban.browaeys@...il.com>,
Doug Anderson <dianders@...omium.org>,
Brian Norris <briannorris@...omium.org>,
Jensen Huang <jensenhuang@...endlyarm.com>, linux-phy@...ts.infradead.org,
linux-arm-kernel@...ts.infradead.org, linux-rockchip@...ts.infradead.org,
linux-kernel@...r.kernel.org, devicetree@...r.kernel.org,
Folker Schwesinger <dev@...ker-schwesinger.de>
Subject: [PATCH 0/3] phy: rockchip: emmc: Enable internal strobe pull-down
by default
Various RK3399 boards, including the Rock Pi 4 series, the NanoPi 4
series and possibly others showed instabilities with some eMMC modules
when operating in HS400 mode [1]. Later, a missing pull-down resistor on
the eMMC strobe line was identified as the root cause of these
instabilities [2].
This series changes the Rockchip eMMC PHY driver to enable the
internal pull-down for the strobe line by default, effectively
restoring the behavior of the vendor kernel [3].
Addressing the problem in the driver avoids fix-ups in individual
board DTs.
As this change makes the optional DT property enable-strobe-pulldown
obsolete, it is replaced by a new property disable-strobe-pulldown,
that, when used, allows to disable the internal pull-down.
While at it, the enable-strobe-pulldown property was removed from the
NanoPi4 series DTS (which was the only user of the property in the kernel).
[1]: https://lore.kernel.org/all/20230705144255.115299-1-chris.obbard@collabora.com/
[2]: https://lore.kernel.org/all/20220822074139.3810-1-jensenhuang@friendlyarm.com/
[3]: https://github.com/rockchip-linux/kernel/blob/develop-4.4/drivers/phy/rockchip/phy-rockchip-emmc.c#L310
Signed-off-by: Folker Schwesinger <dev@...ker-schwesinger.de>
---
Folker Schwesinger (3):
phy: rockchip: emmc: Enable pulldown for strobe line
devicetree: phy: rockchip-emmc: Document changed strobe-pulldown property
arm64: dts: rockchip: Remove enable-strobe-pulldown for NanoPi4 boards
Documentation/devicetree/bindings/phy/rockchip-emmc-phy.txt | 4 ++--
arch/arm64/boot/dts/rockchip/rk3399-nanopi4.dtsi | 1 -
drivers/phy/rockchip/phy-rockchip-emmc.c | 6 +++---
3 files changed, 5 insertions(+), 6 deletions(-)
---
base-commit: 4cece764965020c22cff7665b18a012006359095
change-id: 20240326-rk-default-enable-strobe-pulldown-3356c8cf1b4f
Best regards,
--
Folker Schwesinger <dev@...ker-schwesinger.de>
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