Hi Chunyan, On Wed, Jun 14, 2017 at 11:21 AM, Chunyan Zhang <zhang.chunyan@xxxxxxxxxx> wrote: > The value of property 'clock-cells' is not determined only by the number > of clock outputs in one clock node, it is determined by whether the clock > output in this node can be referenced directly without index. If the > output clock has to be referenced by a index, the clock-cell of this > clock node can't be defined 0. > > Signed-off-by: Chunyan Zhang <zhang.chunyan@xxxxxxxxxx> > --- > Documentation/devicetree/bindings/clock/clock-bindings.txt | 10 ++++++++++ > 1 file changed, 10 insertions(+) > > diff --git a/Documentation/devicetree/bindings/clock/clock-bindings.txt b/Documentation/devicetree/bindings/clock/clock-bindings.txt > index 2ec489e..e2b76b4 100644 > --- a/Documentation/devicetree/bindings/clock/clock-bindings.txt > +++ b/Documentation/devicetree/bindings/clock/clock-bindings.txt > @@ -18,6 +18,9 @@ Required properties: > with a single clock output and 1 for nodes with multiple > clock outputs. > > + There's one exception, please see the description for > + clock-indices below. > + > Optional properties: > clock-output-names: Recommended to be a list of strings of clock output signal > names indexed by the first cell in the clock specifier. > @@ -48,6 +51,13 @@ clock-indices: If the identifying number for the clocks in the node > is not linear from zero, then this allows the mapping of > identifiers into the clock-output-names array. > > + This property not only servers for clocks with multiple serves > + clock outputs, but also for clocks with a single clock > + output whose identifying number is not zero. Why would you want a single clock and a non-zero identifying number? > + So long as clock-indices is set, clock-cells cannot be > + set zero. Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html