Some hardware contains bunches of clocks which must never be turned off. If drivers a) fail to obtain a reference to any of these or b) give up a previously obtained reference during suspend, the common clk framework will attempt to disable them and a platform can fail irrecoverably as a result. Usually the only way to recover from these failures is to reboot.
To avoid either of these two scenarios from catastrophically disabling an otherwise perfectly healthy running system, clocks can be identified as always-on using this property from inside a clocksource's node. The CLK_IGNORE_UNUSED flag will be applied to each clock instance named in this property, thus preventing them from being shut down by the framework. Lee Jones (4): ARM: sti: stih407-family: Supply defines for CLOCKGEN A0 ARM: sti: stih410-clocks: Identify critical clocks as always-on clk: Provide always-on clock support clk: dt: Introduce binding for always-on clock support .../devicetree/bindings/clock/clock-bindings.txt | 34 ++++++++++++++++++++++ arch/arm/boot/dts/stih410-clock.dtsi | 10 +++++++ drivers/clk/clk.c | 11 +++++++ include/dt-bindings/clock/stih407-clks.h | 4 +++ 4 files changed, 59 insertions(+) -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
