From 0d40497d054194768b3ddbf3a676d481b38b96eb Mon Sep 17 00:00:00 2001 From: Douglas Anderson Date: Thu, 10 Mar 2022 13:04:34 -0800 Subject: [PATCH] arm64: dts: qcom: sc7280-herobrine: Fix PCIe regulator glitch at bootup While scoping signals, we found that the PCIe signals weren't compliant at bootup. Specifically, the bootloader was setting up PCIe and leaving it configured, then jumping to the kernel. The kernel was turning off the regulator while leaving the PCIe clock running, which was a violation. In the regulator bindings (and the Linux kernel driver that uses them), there's currently no way to specify that a GPIO-controlled regulator should keep its state at bootup. You've got to pick either "on" or "off". Let's switch it so that the PCIe regulator defaults to "on" instead of "off". This should be a much safer way to go and avoids the timing violation. The regulator will still be turned off later if there are no users. Signed-off-by: Douglas Anderson Reviewed-by: Stephen Boyd Reviewed-by: Matthias Kaehlcke Signed-off-by: Bjorn Andersson Link: https://lore.kernel.org/r/20220310130429.1.Id41fda1d7f5d9230bc45c1b85b06b0fb0ddd29af@changeid --- arch/arm64/boot/dts/qcom/sc7280-herobrine.dtsi | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/arch/arm64/boot/dts/qcom/sc7280-herobrine.dtsi b/arch/arm64/boot/dts/qcom/sc7280-herobrine.dtsi index d57ea4881fa1..3d9b870d440b 100644 --- a/arch/arm64/boot/dts/qcom/sc7280-herobrine.dtsi +++ b/arch/arm64/boot/dts/qcom/sc7280-herobrine.dtsi @@ -180,6 +180,13 @@ pinctrl-names = "default"; pinctrl-0 = <&ssd_en>; + /* + * The bootloaer may have left PCIe configured. Powering this + * off while the PCIe clocks are still running isn't great, + * so it's better to default to this regulator being on. + */ + regulator-boot-on; + vin-supply = <&pp3300_z1>; }; -- 2.34.1