On Fri, Jul 17, 2026 at 05:59:22PM +0200, Miquel Raynal (Schneider Electric) wrote: > A nexus node is some kind of parent device abstracting the outer > connections. They are particularly useful for describing connectors-like > interfaces but not only. Certain IP blocks will typically include inner > blocks and distribute resources to them. > > In the case of clocks, there is already the concept of clock controller, > but this usually indicates some kind of control over the said clock, > ie. gate or rate control. When there is none of this, an existing > approach is to reference the upper clock, which is wrong from a hardware > point of view. > > Nexus nodes are already part of the device-tree specification and clocks > are already mentioned: > https://github.com/devicetree-org/devicetree-specification/blob/v0.4/source/chapter2-devicetree-basics.rst#nexus-nodes-and-specifier-mapping > > Following the introductions of nexus nodes support for interrupts, gpios > and pwms, here is the same logic applied again to the clk subsystem, > just by transitioning from of_parse_phandle_with_args() to > of_parse_phandle_with_args_map(): > > * Nexus OF support: > commit bd6f2fd5a1d5 ("of: Support parsing phandle argument lists through a > nexus node") > * GPIO adoption: > commit c11e6f0f04db ("gpio: Support gpio nexus dt bindings") > * PWM adoption: > commit e71e46a6f19c ("pwm: Add support for pwm nexus dt bindings") > > Only expected Nexus property: > - clock-map: maps inner clocks to inlet clocks > (the other properties have been judged not relevant for clocks) > > Here is an example: > > Example: > soc_clk: clock-controller { > #clock-cells = <1>; > }; > > container: container { > #clock-cells = <1>; > clock-map = <0 &soc_clk 2>, > <1 &soc_clk 6>; > > child-device { > clocks = <&container 1>; > /* This is equivalent to <&soc_clk 6> */ > }; > }; > > The child device does not need to know about the outer implementation, > and only knows about what the nexus provides. The nexus acts as a > pass-through, with no extra control. > > Signed-off-by: Miquel Raynal (Schneider Electric) <[email protected]> > Reviewed-by: Herve Codina <[email protected]> > Reviewed-by: Brian Masney <[email protected]> > ---
Reviewed-by: Frank Li <[email protected]> > drivers/clk/clk-conf.c | 12 ++++++------ > drivers/clk/clk.c | 4 ++-- > 2 files changed, 8 insertions(+), 8 deletions(-) > > diff --git a/drivers/clk/clk-conf.c b/drivers/clk/clk-conf.c > index 303a0bb26e54..5380d43b56a4 100644 > --- a/drivers/clk/clk-conf.c > +++ b/drivers/clk/clk-conf.c > @@ -25,8 +25,8 @@ static int __set_clk_parents(struct device_node *node, bool > clk_supplier) > node); > > for (index = 0; index < num_parents; index++) { > - rc = of_parse_phandle_with_args(node, "assigned-clock-parents", > - "#clock-cells", index, &clkspec); > + rc = of_parse_phandle_with_args_map(node, > "assigned-clock-parents", > + "clock", index, &clkspec); > if (rc < 0) { > /* skip empty (null) phandles */ > if (rc == -ENOENT) > @@ -47,8 +47,8 @@ static int __set_clk_parents(struct device_node *node, bool > clk_supplier) > return PTR_ERR(pclk); > } > > - rc = of_parse_phandle_with_args(node, "assigned-clocks", > - "#clock-cells", index, &clkspec); > + rc = of_parse_phandle_with_args_map(node, "assigned-clocks", > + "clock", index, &clkspec); > if (rc < 0) > goto err; > if (clkspec.np == node && !clk_supplier) { > @@ -121,8 +121,8 @@ static int __set_clk_rates(struct device_node *node, bool > clk_supplier) > rate = rates[index]; > > if (rate) { > - rc = of_parse_phandle_with_args(node, "assigned-clocks", > - "#clock-cells", index, &clkspec); > + rc = of_parse_phandle_with_args_map(node, > "assigned-clocks", > + "clock", index, > &clkspec); > if (rc < 0) { > /* skip empty (null) phandles */ > if (rc == -ENOENT) > diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c > index 45f5d7a4ccc1..6acf042673c3 100644 > --- a/drivers/clk/clk.c > +++ b/drivers/clk/clk.c > @@ -5207,8 +5207,8 @@ static int of_parse_clkspec(const struct device_node > *np, int index, > */ > if (name) > index = of_property_match_string(np, "clock-names", > name); > - ret = of_parse_phandle_with_args(np, "clocks", "#clock-cells", > - index, out_args); > + ret = of_parse_phandle_with_args_map(np, "clocks", "clock", > + index, out_args); > if (!ret) > break; > if (name && index >= 0) > > -- > 2.54.0 >
