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/[email protected]/
[2]: https://lore.kernel.org/all/[email protected]/
[3]: https://github.com/rockchip-linux/kernel/blob/develop-4.4/drivers/phy/rockchip/phy-rockchip-emmc.c#L310
Signed-off-by: Folker Schwesinger <[email protected]>
---
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 <[email protected]>