Serial and GPIOs on A1300 Slate Plus

Technical Support for Routers
1

We are using Slate Plus for an upcoming project and one of the requirements is to have GPIO available. The official GL documentation used to be very good and itemizing out GPIOs but these days it seems they gloss over things and you have to go digging through source code to see for real.

We have found through checking the DTS that the serial pins and “i2c” pins are both attached to GPIOs to operate:
serial_pins: serial_pinmux {
mux {
pins = “gpio60”, “gpio61”;
function = “blsp_uart0”;
bias-disable;
};
};

    i2c_0_pins: i2c_0_pinmux {
            pinmux {
                    pins = "gpio58", "gpio59";
                    function = "blsp_i2c0";
                    bias-disable;
            };
    };

I know serial pins are exposed on this board, and we might be able to use those if we sacrifice serial functions. Two questions:

  1. is i2c exposed or used for anything on the a1300? I do not see headers or pins anywhere on the board, but maybe they just are not labelled/documented well? or are those pins not connected to anything?
  2. Anyone ever tried to reduce the serial port to a single pin instead of both RX and TX? in our case having simply TX would be enough that if there is a crash we could see what was going on. Would prefer not to sacrifice the serial port completely but not sure if that is an option.

Any feedback welcome!

2

For first question:
The i2c is used to control the ET6326 to realize the breathing function of the led. which is implemented in /usr/bin/gl_i2c_led and you can refer to this link to learn about its implementation.

For second question:
I think you need to modify the driver to implement it, or you can refer to this patch? I think you should also encounter other difficulties, if you realize, I hope you can share with me.
https://github.com/gl-inet/gl-infra-builder/blob/main/patches-mt798x-7.6.6.1/3008-support-uart1-no-use-cts-and-rts.patch