[PATCH v2 1/5] arm64: dts: imx8mq-phanbell: Keep the GPU rail on

[Rudi Heitbaum]

BUCK3 feeds the GPU rail, and unlike every other regulator on this board
it is marked neither regulator-always-on nor referenced by any consumer.
Once a driver for the BD71837 is present the regulator core finds it
unused and switches it off when it completes initialisation:

  buck3: disabling

which takes the board out about thirty seconds into the boot.

Mark it always-on, matching the other seven bucks and all seven LDOs.

Handing it to the GPU power domain instead, the way imx8mq-librem5.dtsi
does, describes the hardware better but does not work here: the board
dies silently the moment anything first uses the GPU, in roughly half of
boots. With that link removed the same image boots reliably. Whatever
goes wrong in the domain to regulator sequencing on this platform, a
rail that is simply never switched avoids it.

Signed-off-by: Rudi Heitbaum <rudi at heitbaum.com>
---
 arch/arm64/boot/dts/freescale/imx8mq-phanbell.dts | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/arm64/boot/dts/freescale/imx8mq-phanbell.dts b/arch/arm64/boot/dts/freescale/imx8mq-phanbell.dts
index e34045d10a12..c06a787a4013 100644
--- a/arch/arm64/boot/dts/freescale/imx8mq-phanbell.dts
+++ b/arch/arm64/boot/dts/freescale/imx8mq-phanbell.dts
@@ -156,6 +156,7 @@ buck3: BUCK3 {
 				regulator-min-microvolt = <700000>;
 				regulator-max-microvolt = <1300000>;
 				regulator-boot-on;
+				regulator-always-on;
 				rohm,dvs-run-voltage = <900000>;
 			};
 
-- 
2.53.0