Device tree configuration for the I2C busses on the AST24XX and AST25XX SoCs.
Required Properties:
- #address-cells : should be 1
- #size-cells : should be 0
- reg : address offset and range of bus
- compatible : should be “aspeed,ast2400-i2c-bus”
or "aspeed,ast2500-i2c-bus"
- clocks : root clock of bus, should reference the APB
clock in the second cell
- resets : phandle to reset controller with the reset number in
the second cell
- interrupts : interrupt number
- interrupt-parent : interrupt controller for bus, should reference a
aspeed,ast2400-i2c-ic or aspeed,ast2500-i2c-ic interrupt controller
Optional Properties:
- bus-frequency : frequency of the bus clock in Hz defaults to 100 kHz when not
specified
- multi-master : states that there is another master active on this bus.
Example:
i2c {
compatible = “simple-bus”;
#address-cells = <1>;
#size-cells = <1>;
ranges = <0 0x1e78a000 0x1000>;
i2c_ic: interrupt-controller@0 {
#interrupt-cells = <1>;
compatible = "aspeed,ast2400-i2c-ic";
reg = <0x0 0x40>;
interrupts = <12>;
interrupt-controller;
};
i2c0: i2c-bus@40 {
#address-cells = <1>;
#size-cells = <0>;
#interrupt-cells = <1>;
reg = <0x40 0x40>;
compatible = "aspeed,ast2400-i2c-bus";
clocks = <&syscon ASPEED_CLK_APB>;
resets = <&syscon ASPEED_RESET_I2C>;
bus-frequency = <100000>;
interrupts = <0>;
interrupt-parent = <&i2c_ic>;
};
};