On 06/15, Ricardo Ribalda Delgado wrote:

Hi Stephen

Assume this device tree overlay:


&bus0{

axi_clk: axi_clk {
compatible = "fixed-clock";
#clock-cells = <0x0>;
clock-frequency = <125000000>;
};

iic_0: iic {
#address-cells = <1>;
#size-cells = <1>;
compatible = "xlnx,xps-iic-2.00.a";
reg = < 0x00030000 0x10000 >;
interrupt-parent = <&xps_intc_0>;
interrupts = < 2 2 >;
clocks = <&axi_clk>;
 } ;

}

Which is basically a new i2c master and a fixed clock definition.

The fixed clock driver will only be probed to the driver at arch
initialization, when of_clk_init is called.  The device overlay can be
added at any point, usually after arch init. Which will result in ii_0
failing to probe,  because it is missing its clock.

This changeset allows fixed clocks to be added after of_clk_init is
called, by converting the driver into a platform driver.

Ok, so this is about supporting clks in overlays. I2C only comes
into the picture here because it's a consumer and happens to also
be on the same overlay.

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