Add description for assigned-clocks properties from clock-binding.txt in
the Linux kernel.
This is relicensed from GPL-2.0 (the default) to BSD-2-Clause. The Cc list
are the original authors.
Cc: Sylwester Nawrocki <s.nawrocki@xxxxxxxxxxx>
Cc: Stephen Boyd <swboyd@xxxxxxxxxxxx>
Signed-off-by: Rob Herring <robh@xxxxxxxxxx>
---
Please ack for the license change.
dtschema/schemas/clock/clock.yaml | 38 +++++++++++++++++++++++++++++++
1 file changed, 38 insertions(+)
diff --git a/dtschema/schemas/clock/clock.yaml b/dtschema/schemas/clock/clock.yaml
index 2416d046087c..5299653b80b6 100644
--- a/dtschema/schemas/clock/clock.yaml
+++ b/dtschema/schemas/clock/clock.yaml
@@ -19,6 +19,44 @@ description: |
output on a device. The length of a clock specifier is defined by the
value of a #clock-cells property in the clock provider node.
+ Assigned clock parents and rates
+ --------------------------------
+
+ Some platforms may require initial configuration of default parent clocks
+ and clock frequencies. Such a configuration can be specified in a device tree
+ node through assigned-clocks, assigned-clock-parents and assigned-clock-rates
+ properties. The assigned-clock-parents property should contain a list of parent
+ clocks in the form of a phandle and clock specifier pair and the
+ assigned-clock-rates property should contain a list of frequencies in Hz. Both
+ these properties should correspond to the clocks listed in the assigned-clocks
+ property.
+
+ To skip setting parent or rate of a clock its corresponding entry should be
+ set to 0, or can be omitted if it is not followed by any non-zero entry.
+
+ serial@a000 {
+ compatible = "fsl,imx-uart";
+ reg = <0xa000 0x1000>;
+ ...
+ clocks = <&osc 0>, <&pll 1>;
+ clock-names = "baud", "register";
+
+ assigned-clocks = <&clkcon 0>, <&pll 2>;
+ assigned-clock-parents = <&pll 2>;
+ assigned-clock-rates = <0>, <460800>;
+ };
+
+ In this example the <&pll 2> clock is set as parent of clock <&clkcon 0> and
+ the <&pll 2> clock is assigned a frequency value of 460800 Hz.
+
+ Configuring a clock's parent and rate through the device node that consumes
+ the clock can be done only for clocks that have a single user. Specifying
+ conflicting parent or rate configuration in multiple consumer nodes for
+ a shared clock is forbidden.
+
+ Configuration of common clocks, which affect multiple consumer devices can
+ be similarly specified in the clock provider node.
+
# always select the core schema
select: true
--
2.34.1
