| Message ID | 20220131080526.1171072-4-andrej.picej@norik.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | PHYTEC i.MX 6UL/ULL devicetree patches | expand |
On Mon, Jan 31, 2022 at 09:05:25AM +0100, Andrej Picej wrote: > From: Yunus Bas <y.bas@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@phytec.de> > Signed-off-by: Andrej Picej <andrej.picej@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@52 { > }; > }; > > +®_3p0 { > + regulator-min-microvolt = <3000000>; > + regulator-always-on; Rather than setting it always-on, shouldn't the consumer of the regulator turn it on/off as needed? Shawn > +}; > + > &snvs_poweroff { > status = "okay"; > }; > -- > 2.25.1 >
On 12. 02. 22 06:46, Shawn Guo wrote: > On Mon, Jan 31, 2022 at 09:05:25AM +0100, Andrej Picej wrote: >> From: Yunus Bas <y.bas@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@phytec.de> >> Signed-off-by: Andrej Picej <andrej.picej@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@52 { >> }; >> }; >> >> +®_3p0 { >> + regulator-min-microvolt = <3000000>; >> + regulator-always-on; > > Rather than setting it always-on, shouldn't the consumer of the > regulator turn it on/off as needed? Sorry for late response, but I had to look into this a bit to see the reason for using always-on. The consumer should turn the regulator on/off, but the consumer doesn't do that. If regulator is not specified as always-on the regulator stays in disabled state, even when usb device is used. That's why this was added here. This should probably be fixed on consumer side. If you want I can drop the patch from this series and submit the fixed version when the stuff gets resolved. BR, Andrej
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@52 { }; }; +®_3p0 { + regulator-min-microvolt = <3000000>; + regulator-always-on; +}; + &snvs_poweroff { status = "okay"; };