[PATCH 3/4] ARM: dts: imx6ul: phycore: Change USB LDO voltage for usb compliance

Andrej Picej andrej.picej at norik.com
Wed Dec 1 04:53:26 PST 2021


From: Yunus Bas <y.bas at phytec.de>

According to the NXP usb compliance reference, the USB data lines for
Full/Low speed are connected to the ARM USB LDO, which is set to
minimum-voltage = 2.6V and maximum-voltage = 3.4 V. When the regulator
is deactivated, the data lines are defaulty driven with 2.6V, which is
not USB Full-Speed compliant. To be compliant, we need to activate the
USB LDO regulator and set it to the value of 3V, which is the specified
value in the USB specification.

Signed-off-by: Yunus Bas <y.bas at phytec.de>
Signed-off-by: Andrej Picej <andrej.picej at norik.com>
---
 arch/arm/boot/dts/imx6ul-phytec-phycore-som.dtsi | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/arch/arm/boot/dts/imx6ul-phytec-phycore-som.dtsi b/arch/arm/boot/dts/imx6ul-phytec-phycore-som.dtsi
index 3cddc68917a0..2e03be3d43ec 100644
--- a/arch/arm/boot/dts/imx6ul-phytec-phycore-som.dtsi
+++ b/arch/arm/boot/dts/imx6ul-phytec-phycore-som.dtsi
@@ -83,6 +83,11 @@ eeprom at 52 {
 	};
 };
 
+&reg_3p0 {
+	regulator-min-microvolt = <3000000>;
+	regulator-always-on;
+};
+
 &snvs_poweroff {
 	status = "okay";
 };
-- 
2.25.1




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