u-boot/doc/device-tree-bindings/i2c/i2c-gpio.txt

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I2C gpio device binding
=======================
Driver:
- drivers/i2c/i2c-gpio.c
Software i2c device-tree node properties:
Required:
* #address-cells = <1>;
* #size-cells = <0>;
* compatible = "i2c-gpio";
* gpios = <sda ...>, <scl ...>;
Optional:
* i2c-gpio,delay-us = <5>;
The resulting transfer speed can be adjusted by setting the delay[us]
between gpio-toggle operations. Speed [Hz] = 1000000 / 4 * udelay[us],
It not defined, then default is 5us (~50KHz).
Example:
i2c-gpio@1 {
#address-cells = <1>;
#size-cells = <0>;
compatible = "i2c-gpio";
gpios = <&gpd1 0 GPIO_ACTIVE_HIGH>, /* SDA */
<&gpd1 1 GPIO_ACTIVE_HIGH>; /* CLK */
i2c-gpio,delay-us = <5>;
some_device@5 {
compatible = "some_device";
reg = <0x5>;
...
};
};