@@ -169,6 +169,22 @@ a shared clock is forbidden.
Configuration of common clocks, which affect multiple consumer devices can
be similarly specified in the clock provider node.
+==Critical clocks==
+
+Some platforms require clock to be always running, e.g. because those clock
+supply devices which are not otherwise attached to the system. One example
+is a system where the SoC serves as a crystal oscillator replacement for a
+programmable logic device. The critical-clock property of a clock controller
+allows listing clock which must never be turned off.
+
+ clock-controller@a000f000 {
+ compatible = "vendor,clk95;
+ reg = <0xa000f000 0x1000>
+ #clocks-cells = <1>;
+ ...
+ critical-clocks = <UART3_CLK>, <SPI5_CLK>;
+ };
+
==Protected clocks==
Some platforms or firmwares may not fully expose all the clocks to the OS, such
Some platforms require clock to be always running, e.g. because those clock supply devices which are not otherwise attached to the system. One example is a system where the SoC serves as a crystal oscillator replacement for a programmable logic device. The critical-clock property of a clock controller allows listing clock which must never be turned off. The implementation here is similar to "protected-clock". Signed-off-by: Marek Vasut <marex@denx.de> Cc: Matti Vaittinen <matti.vaittinen@fi.rohmeurope.com> Cc: Michael Turquette <mturquette@baylibre.com> Cc: Rob Herring <robh+dt@kernel.org> Cc: Stephen Boyd <sboyd@kernel.org> Cc: devicetree@vger.kernel.org Cc: linux-power@fi.rohmeurope.com To: linux-clk@vger.kernel.org --- .../devicetree/bindings/clock/clock-bindings.txt | 16 ++++++++++++++++ 1 file changed, 16 insertions(+)