So I figured it out by now. It didn't really work with overlay but using the main .dtsi file worked.
pca9635.dtsi

&i2c {
    pca9635@8 {
        compatible = "nxp,pca9635";
        reg = <0x08>;
        #address-cells = <1>;
        #size-cells = <0>;
        status = "okay";

        led@0 {
            label = "led0";
            reg = <0>;
            default-state = "off";
        };

        led@1 {
            label = "led1";
            reg = <1>;
            default-state = "off";
        };

        led@2 {
            label = "led2";
            reg = <2>;
            default-state = "off";
        };

        led@3 {
            label = "led3";
            reg = <3>;
            default-state = "off";
        };

        led@4 {
            label = "led4";
            reg = <4>;
            default-state = "off";
        };

        led@5 {
            label = "led5";
            reg = <5>;
            default-state = "off";
        };

        led@6 {
            label = "led6";
            reg = <6>;
            default-state = "off";
        };

        led@7 {
            label = "led7";
            reg = <7>;
            default-state = "off";
        };

        led@8 {
            label = "led8";
            reg = <8>;
            default-state = "off";
        };

        led@9 {
            label = "led9";
            reg = <9>;
            default-state = "off";
        };

        led@10 {
            label = "led10";
            reg = <10>;
            default-state = "off";
        };

        led@11 {
            label = "led11";
            reg = <11>;
            default-state = "off";
        };

        led@12 {
            label = "led12";
            reg = <12>;
            default-state = "off";
        };

        led@13 {
            label = "led13";
            reg = <13>;
            default-state = "off";
        };

        led@14 {
            label = "led14";
            reg = <14>;
            default-state = "off";
        };

        led@15 {
            label = "led15";
            reg = <15>;
            default-state = "off";
        };
    };
};

placed in the build folder

/home/thomas/openwrt-wallcontroller/target/linux/ramips/dts

and lastly adding an include to the omega .dtsi

mt7628an_onion_omega2.dtsi

#include "mt7628an.dtsi"
#include "pca9635.dtsi"
#include <dt-bindings/gpio/gpio.h>
#include <dt-bindings/input/input.h>

Hi Onioneers!
I am building a project with stacked PCB's. The first PCB contains the Omega2S+ and a CP2102 for Serial Connection. Second PCB contains RJ45, PoE and PSU Components.
When Connecting only the second PCB to my Switch with PoE the 3V3 LED lights up and I can see in my switch that PoE is detected correctly and it's pulling about 0.9W.
I then combined the two PCB's together and used USB to my PC to create a Serial Connection (No Ethernet connected). In this case the 5V of the USB goes to the 5V Rail on the PSU PCB and gets regulated down to 3V3 to supply the omega.
I then connected Ethernet with a non PoE port. It gets detected and I could ssh into the omega and worked for 20 minutes on it. I then unplugged the USB Cable and plugged the Ethernet into a PoE Port. This led to the board shorting all components. I had to replace CP2101, Omega and both Voltage Regulators. What I'm not sure is why this doesn't happen on the USB but with the PoE.
I attached the two schematics. The boards are connected via the 10pin connector.
Any Hint or Idea what could cause this would be greatly appreciated.

So I figured it out by now. It didn't really work with overlay but using the main .dtsi file worked.
pca9635.dtsi

&i2c {
    pca9635@8 {
        compatible = "nxp,pca9635";
        reg = <0x08>;
        #address-cells = <1>;
        #size-cells = <0>;
        status = "okay";

        led@0 {
            label = "led0";
            reg = <0>;
            default-state = "off";
        };

        led@1 {
            label = "led1";
            reg = <1>;
            default-state = "off";
        };

        led@2 {
            label = "led2";
            reg = <2>;
            default-state = "off";
        };

        led@3 {
            label = "led3";
            reg = <3>;
            default-state = "off";
        };

        led@4 {
            label = "led4";
            reg = <4>;
            default-state = "off";
        };

        led@5 {
            label = "led5";
            reg = <5>;
            default-state = "off";
        };

        led@6 {
            label = "led6";
            reg = <6>;
            default-state = "off";
        };

        led@7 {
            label = "led7";
            reg = <7>;
            default-state = "off";
        };

        led@8 {
            label = "led8";
            reg = <8>;
            default-state = "off";
        };

        led@9 {
            label = "led9";
            reg = <9>;
            default-state = "off";
        };

        led@10 {
            label = "led10";
            reg = <10>;
            default-state = "off";
        };

        led@11 {
            label = "led11";
            reg = <11>;
            default-state = "off";
        };

        led@12 {
            label = "led12";
            reg = <12>;
            default-state = "off";
        };

        led@13 {
            label = "led13";
            reg = <13>;
            default-state = "off";
        };

        led@14 {
            label = "led14";
            reg = <14>;
            default-state = "off";
        };

        led@15 {
            label = "led15";
            reg = <15>;
            default-state = "off";
        };
    };
};

placed in the build folder

/home/thomas/openwrt-wallcontroller/target/linux/ramips/dts

and lastly adding an include to the omega .dtsi

mt7628an_onion_omega2.dtsi

#include "mt7628an.dtsi"
#include "pca9635.dtsi"
#include <dt-bindings/gpio/gpio.h>
#include <dt-bindings/input/input.h>

Hi All,

for my custom hardware i need to drive some LED's and since the Software PWM wasn't stable enough I opted for an LED driver. I compiled a custom firmware (24.10) with the leds-pca963x kernel module and I can confirm that it's loaded. I have my PCA9635 connect to I2C on address 0x8 and can see it with i2cdetect.
I try adding the device via sys/class like:

echo pca9635 0x08 > /sys/class/i2c-dev/i2c-0/device/new_device

running desmg afterwards shows that it tried to load the driver:

[  949.521145] leds-pca963x 0-0008: Node (null) must define between 1 and 16 LEDs
[  949.528588] leds-pca963x: probe of 0-0008 failed with error -22
[  949.534638] i2c i2c-0: new_device: Instantiated device pca9635 at 0x08

However it looks like it needs the LED's defined via DTS. I never used that so I forked the onion-dts-overlay and tried to add my own but that didn't work either.

/dts-v1/;
/plugin/;

/ {
    compatible = "onion,omega2";

    fragment@0 {
        target = <&i2c0>;  // adapt to your bus if needed

        __overlay__ {
            pca9635: pca9635@08 {
                compatible = "nxp,pca9635";
                reg = <0x08>;
                #address-cells = <1>;
                #size-cells = <0>;

                led@0 {
                    label = "user:led0";
                    reg = <0>;
                };

                led@1 {
                    label = "user:led1";
                    reg = <1>;
                };
                // Add more as needed
            };
        };
    };
};

I'm not sure where to start. Ideally I'd add everything into one package for the firmware compilation but I'm lost where that should happen.

Hi Onioneers!
I am building a project with stacked PCB's. The first PCB contains the Omega2S+ and a CP2102 for Serial Connection. Second PCB contains RJ45, PoE and PSU Components.
When Connecting only the second PCB to my Switch with PoE the 3V3 LED lights up and I can see in my switch that PoE is detected correctly and it's pulling about 0.9W.
I then combined the two PCB's together and used USB to my PC to create a Serial Connection (No Ethernet connected). In this case the 5V of the USB goes to the 5V Rail on the PSU PCB and gets regulated down to 3V3 to supply the omega.
I then connected Ethernet with a non PoE port. It gets detected and I could ssh into the omega and worked for 20 minutes on it. I then unplugged the USB Cable and plugged the Ethernet into a PoE Port. This led to the board shorting all components. I had to replace CP2101, Omega and both Voltage Regulators. What I'm not sure is why this doesn't happen on the USB but with the PoE.
I attached the two schematics. The boards are connected via the 10pin connector.
Any Hint or Idea what could cause this would be greatly appreciated.

That makes Sense, so my Power Wiring should be correct. I see that in your schematic and in the datasheet the HW Reset and VDD_FLASH are connected via transistors. Any Benefit to that compared to just pulling them to GND via a Switch? CPU_RST_SWITCH simply bridges to GND.

Interestingly in this Schematic they use the CP2102-GMT which seems to be the older model compared to the CP2102N Series. It does not have a VIO pin. However i rechecked the datasheet again and you are right that the VIO should be to 3.3V and RST then be bound to that 3.3V with a 1K resistor.
I also implemented a resistor divider to VBUS as recommended in the data sheet althought not scrictly needed. What I found odd in the schematic that you linked though is that the Omega is only connected to VDD_Flash but not to 3.3V. Any Idea why?

Hi All,

I am currently designing a multi PCB project with the Omega2S.
My issue is that I'm not able to get a Serial Connection to the Omega via the CP2102. The COM Port is detected and I can open a Session with Putty but it stays blank.
I also noticed that the Omega is consuming 800mA of current with occasional Spikes to 1.2A. That sounds like I fried it somehow.
Is there something fundamentally wrong with how I wired up the Omega or the CP2102?