Hi Morimoto-san,
On Wed, Nov 29, 2023 at 12:13 AM Kuninori Morimoto
<kuninori.morimoto.gx@xxxxxxxxxxx> wrote:
> > > +static int __init cpg_mssr_reserved_init(struct cpg_mssr_priv *priv,
> > > + const struct cpg_mssr_info *info)
> > > +{
> > > + struct device_node *root = of_find_node_by_path("/soc");
> >
> > 'root' is '/', so I find this slightly confusing.
> (snip)
> > > + * scif5: serial@e6f30000 {
> > > + * ...
> > > + * => clocks = <&cpg CPG_MOD 202>,
> > > + * <&cpg CPG_CORE R8A7795_CLK_S3D1>,
> > > + * <&scif_clk>;
> > > + * ...
> > > + * status = "reserved";
> > > + * };
> > > + */
> > > + for_each_reserved_child_of_node(root, node) {
> >
> > Don't you really want to find all reserved nodes in the DT rather than
> > just child nodes of a single node?
>
> The all devices which we need to check (and ignore the clock) in this
> driver is defined under /soc for now.
"For now" is the right clause: all module clocks are inputs to on-SoC
devices under the "soc" node.
However, once the clock drivers become aware[1]* of programmable (core)
clocks driving the real-time CPU cores not running Linux, you may need
special handling for these, too.
[1] On R-Car V3U, the clock driver already supports R8A779A0_CLK_ZR,
but it is a fixed clock that cannot be disabled nor changed.
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
