Re: [PATCH] clk: Add fault tolerance to of_clk_hw_onecell_get()

[Chuan Liu]

Hi Stephen:

    After reviewing all CCF drivers referencing of_clk_hw_onecell_get(),
I confirmed their corresponding binding *.yaml files define
'#clock-cells' as 'const: 1'.

Therefore, the case I previously described is currently disallowed.
Please ignore this patch. Thanks.


On 8/1/2025 12:45 AM, Stephen Boyd wrote:
> [ EXTERNAL EMAIL ]
>
> Quoting Chuan Liu via B4 Relay (2025-07-31 05:39:58)
> > From: Chuan Liu <chuan.liu@xxxxxxxxxxx>
> >
> > In specific cases, even a clk_provider managing only a single clock may
> > reference of_clk_hw_onecell_get() to access its member clocks, as seen
> > in implementations like clk-scmi.
> >
> > For a clk_provider with only one clock, when calling
> > of_parse_phandle_with_args(), the phandle_args->args[] members are not
> > assigned. In this case, the reference to phandle_args->args[0] in
> > of_clk_hw_onecell_get() becomes invalid. If phandle_args->args[0]
> > initially contains a non-zero value, this will trigger an error.
> >
> > Signed-off-by: Chuan Liu <chuan.liu@xxxxxxxxxxx>
> > ---
> > Error conditions observed:
> >
> > scmi_clk: protocol@14 {
> >          reg = <0x14>;
> >          #clock-cells = <0>;
> > };
> >
> > phandle1: clock-controller@1 {
> >          #clock-cells = <1>;
> > }
> >
> > clock-consumer@2 {
> >          assigned-clocks = <&phandle1 1>,
> >                            <&scmi_clk>;
> >          assigned-clock-rates = <xxx>,
> >                                 <xxx>;
> > }
> >
> > Under these conditions, executing of_clk_set_defaults() triggers the
> > error: 'of_clk_hw_onecell_get: invalid index 1'.
> Please write a KUnit test.