Re: [PATCH 2/3] clk: let of_clk_get_parent_name() fail for invalid clock-indices

Stephen Boyd
2015-11-20T17:45:14Z

On 11/20, Masahiro Yamada wrote:
> Currently, of_clk_get_parent_name() returns a wrong parent clock name
> when "clock-indices" property exists and the given index is not found
> in the property. In this case, NULL should be returned.
>
> For example,
>
> oscillator {
> compatible = "myclocktype";
> #clock-cells = <1>;
> clock-indices = <1>, <3>;
> clock-output-names = "clka", "clkb";
> };
>
> Currently, of_clk_get_parent_name(np, 0) returns "clka", but should
> return NULL because "clock-indices" does not contain <0>.

What is np pointing at? Something like:

consumer {
clocks = <&oscillator 0>;
};

Which would be invalid DT because oscillator doesn't have an
output for index 0?

>
> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
> @@ -3068,17 +3065,20 @@ const char *of_clk_get_parent_name(struct device_node *np, int index)
> return NULL;
>
> index = clkspec.args_count ? clkspec.args[0] : 0;
> - count = 0;
>
> /* if there is an indices property, use it to transfer the index
> * specified into an array offset for the clock-output-names property.
> */
> - of_property_for_each_u32(clkspec.np, "clock-indices", prop, vp, pv) {
> - if (index == pv) {
> - index = count;
> - break;
> - }
> - count++;
> + list = of_get_property(clkspec.np, "clock-indices", &len);
> + if (list) {
> + len /= sizeof(*list);
> + for (i = 0; i < len; i++)
> + if (index == be32_to_cpup(list++)) {
> + index = i;
> + break;
> + }
> + if (i == len)
> + return NULL;
> }

Why can't we leave everything in place and check count == len at
the end? i.e.

of_property_for_each_u32(clkspec.np, "clock-indices", prop, vp, pv) {
if (index == pv) {
index = count;
break;
}
count++;
}

if (count == of_property_count_u32_elems(clkspec.np, "clock-indices"))
return NULL

?

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