Re: [RFCv1 2/3] ARM: dts: meson8b: odroidc1: fix USB power supplies for phy

[Anand Moon <linux.amoon@gmail.com>]

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Hi Martin,

On Wed, 6 Feb 2019 at 16:58, Martin Blumenstingl
<martin.blumenstingl@googlemail.com> wrote:
>
> Hi Anand,
>
> On Tue, Feb 5, 2019 at 8:53 PM Anand Moon <linux.amoon@gmail.com> wrote:
> [...]
> > > my interpretationfor the Amlogic SoCs is:
> > > - vusb_a and vusb_d are generated internally, not sure if there's an
> > > external fixed regulator
> > > - there is no phy-supply (the PHY itself is powered by clock-gating
> > > using the CLKID_USB clock)
> > > - usb0 VBUS is controlled by GPIOAO_5
> > >
> >
> > But as per the device tree binding
> >
> > [0] https://elixir.bootlin.com/linux/v5.0-rc5/source/Documentation/devicetree/bindings/phy/meson8b-usb2-phy.txt
> > [1] https://elixir.bootlin.com/linux/v5.0-rc5/source/Documentation/devicetree/bindings/phy/phy-bindings.txt
> >
> > its uses phy-supply to enable power to usb phy which seem to be correct option.
> phy-bindings.txt states that "phy-supply" is a "Phandle to a regulator
> that provides power to the PHY".
> I have written the example in meson8b-usb2-phy.txt and I think it's
> wrong (back when I wrote it I didn't know about the "vbus-supply"
> property on the controller and I didn't know about the VBUS
> constraints).
>
> I believe that the phy-supply property is intended for PHYs which need
> an external power supply (for example because they are not embedded
> into a SoC or if the SoC has separate voltage inputs for the PHY).
> I'm not aware of any PHY supply voltage on the Amlogic SoCs (I believe
> this is done internally within the SoC). instead they use clock gating
> to power down the PHY.
>
> as far as I understand the VBUS signal it depends on the USB mode:
> - host provides VBUS
> - peripheral devices are powered using this voltage
> - with OTG VBUS needs to be turned on or off depending on the current
> mode (host or peripheral)
> with the "phy-supply" property there's no way to manage the regulator
> depending on the USB mode (host or peripheral), it will always be
> "on".
>
>
> Regards
> Martin

Thanks for the clarification.
But this dose not work setting the usb1_phy to use vbus-supply.

 &usb1_phy {
        status = "okay";
+       vbus-supply = <&usb_vbus>;
 };

I am attaching a small patch for testing.
[0] usbvbus.patch

Here is the summary of the above patch.

1. hot-plugins of usb device is not working.
2. only cold/warm boot let the device come up.
3. not power is supplied to the usb ports.
4. no power module is registered with the regulator summary.

# cat /sys/kernel/debug/regulator/regulator_summary
 regulator                      use open bypass  opmode voltage
current     min     max
---------------------------------------------------------------------------------------
 regulator-dummy                  4    3      0 unknown     0mV
0mA     0mV     0mV
    c90c0000.usb                  1
0mA     0mV     0mV
    c90c0000.usb                  1
0mA     0mV     0mV
    VCCK                          1    1      0 unknown   860mV
0mA   860mV  1140mV
       cpu0                       0
0mA   860mV   860mV
 P5V0                             2    4      0 unknown  5000mV
0mA  5000mV  5000mV
    VCC1V8                        1    1      0 unknown  1800mV
0mA  1800mV  1800mV
       c1108680.adc               1
0mA     0mV     0mV
    VCC3V3                        1    2      0 unknown  3300mV
0mA  3300mV  3300mV
       VDD_RTC                    0    0      0 unknown   900mV
0mA   900mV   900mV
       TFLASH_VDD                 1    1      0 unknown  3300mV
0mA  3300mV  3300mV
          c1108c20.mmc:slot@1     1
0mA  3300mV  3400mV
    DDR_VDDC                      0    0      0 unknown  1500mV
0mA  1500mV  1500mV
    USB_VBUS                      0    0      0 unknown  5000mV
0mA  5000mV  5000mV
 TF_IO                            0    1      0 unknown  3300mV
0mA  1800mV  3300mV
    c1108c20.mmc:slot@1           0
0mA     0mV     0mV

*So from my side phy-supply is the correct option.*

Best Regards
-Anand

[-- Attachment #2: usbvbus.patch --]
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diff --git a/arch/arm/boot/dts/meson8b-odroidc1.dts b/arch/arm/boot/dts/meson8b-odroidc1.dts
index 58669abda259..a04f5633adcf 100644
--- a/arch/arm/boot/dts/meson8b-odroidc1.dts
+++ b/arch/arm/boot/dts/meson8b-odroidc1.dts
@@ -83,6 +83,20 @@
 		regulator-max-microvolt = <5000000>;
 	};
 
+	usb_vbus: regulator-usb-vbus {
+		compatible = "regulator-fixed";
+
+		regulator-name = "USB_VBUS";
+		regulator-min-microvolt = <5000000>;
+		regulator-max-microvolt = <5000000>;
+		/*
+		 * signal name from schematics: PWREN
+		 */
+		gpio = <&gpio_ao GPIOAO_5 GPIO_ACTIVE_HIGH>;
+		enable-active-high;
+		vin-supply = <&p5v0>;
+	};
+
 	tflash_vdd: regulator-tflash_vdd {
 		/*
 		 * signal name from schematics: TFLASH_VDD_EN
@@ -297,6 +311,7 @@
 
 &usb1_phy {
 	status = "okay";
+	vbus-supply = <&usb_vbus>;
 };
 
 &usb1 {

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