Acivate I2C on AML-S805X-AC (La Frite)

Software
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I am able to get I2C to work on pin 27 and 28 (on La Frite) by using and modifying i2c-b.dts. According to the spreadsheet pins 27 and 28 are GPIODV 24 and 25. And these two are i2c_A instead of i2c_B.

Open i2c-b.dts for aml-s805 (path: libretech-wiring-tool/libre-computer/aml-s805x-ac/dt/i2c-b.dts).
Modify these:

  • replace &i2c_b_pins to &i2c_a_pins.
  • replace “GPIODV_26”,“GPIODV_27” with “GPIODV_24”,“GPIODV_25”
  • replace <&i2c_B> in target of fragment@2 with <&i2c_A>.
  • save changes
  • delete i2c-b.dtbo if it is already generated
  • compile the entire library by executing: sudo make. This should only generate a new i2c-b.dtbo since we delete this in earlier step.
  • merge it: sudo ./ldto merge i2c-b
  • reboot the computer
  • once rebooted, issue i2cdetect -y 2. You should see your I2C device/s there.
    Hope I am not forgetting anything.

/*

  • Copyright (c) 2017 BayLibre, SAS.
  • Author: Neil Armstrong narmstrong@baylibre.com
  • SPDX-License-Identifier: (GPL-2.0+ OR MIT)
    */

/*

  • Overlay aimed to enable I2C_B on Header 7J1 :
  • Pins 27 (SDA), 28 (SCL)
    */

/dts-v1/;
/plugin/;

/ {
compatible = “libretech,aml-s805x-ac”, “amlogic,s805x”, “amlogic,meson-gxl”;

fragment@0 {
	target-path = "/aliases";

	__overlay__ {
		i2c2 = "/soc/cbus@c1100000/i2c@87c0";
	};
};

fragment@1 {
	target = <&i2c_a_pins>;

	__overlay__ {
		cfg {
			pins = "GPIODV_24", "GPIODV_25";
			bias-pull-up;
		};
	};
};

fragment@2 {
	target = <&i2c_A>;
	
	__overlay__ {
		status = "okay";
		pinctrl-0 = <&i2c_a_pins>;
		pinctrl-names = "default";
	};
};

};

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