extres: add clk_get_by_ofw_node_index

[jmcneill]

Summary

This diff adds clk_get_by_ofw_node_index, which is like clk_get_by_ofw_index but operates on a specific OF node instead of the passed in device's OF node.

I'm using this in my Allwinner A64 branch for a clock node that looks like this:

bus_gates {
    #clock-cells = <1>;
    compatible = "allwinner,sunxi-multi-bus-gates-clk";
    ...
    ahb1_parent {
        clocks = <&ahb1>;
        ...
    }
    ahb2_parent {
        clocks = <&ahb2>;
        ...
    }
}

[mmel]

Because this is not that uncommon situation, i think that missing OFW node argument is clear issue in <foo>_get_by_ofw_<bar> interface design. Due to this,
i prefer to add node as argument to existing functions.

@@ -1196,7 +1196,7 @@ clk_get_by_id(device_t dev, struct clkdom *clkdom, intptr_t id, clk_t *clk)
 #ifdef FDT

 int
-clk_get_by_ofw_index(device_t dev, int idx, clk_t *clk)
+clk_get_by_ofw_index(device_t dev, phandle_t cnode, int idx, clk_t *clk)
 {
        phandle_t cnode, parent, *cells;
        device_t clockdev;
@@ -1206,7 +1206,8 @@ clk_get_by_ofw_index(device_t dev, int idx, clk_t *clk)

        *clk = NULL;

-       cnode = ofw_bus_get_node(dev);
+       if (cnode <= 0)
+               cnode = ofw_bus_get_node(dev);
        if (cnode <= 0) {
                device_printf(dev, "%s called on not ofw based device\n",
                 __func__);

[andrew]

In D6957#146073, @meloun-miracle-cz wrote:

Because this is not that uncommon situation, i think that missing OFW node argument is clear issue in <foo>_get_by_ofw_<bar> interface design. Due to this,
i prefer to add node as argument to existing functions.

I don't think you'll get this past re@. It changes KBI so for now we would need to create a second function. This can then be fixed in 12.

[mmel]

Hmm, right, i agree. I forget that we are in KBI freeze state. So feel free to commit this, i will change all all <foo>_get_by_ofw_<bar>() functions later in 12.