Hi Lee, On Tue, Apr 07, 2015 at 07:43:59PM +0100, Lee Jones wrote: > Signed-off-by: Lee Jones <lee.jones@xxxxxxxxxx> > --- > .../devicetree/bindings/clock/clock-bindings.txt | 38 ++++++++++++++++++++++ > 1 file changed, 38 insertions(+) > > diff --git a/Documentation/devicetree/bindings/clock/clock-bindings.txt b/Documentation/devicetree/bindings/clock/clock-bindings.txt > index 06fc6d5..daf3323 100644 > --- a/Documentation/devicetree/bindings/clock/clock-bindings.txt > +++ b/Documentation/devicetree/bindings/clock/clock-bindings.txt > @@ -44,6 +44,44 @@ For example: > clocks by index. The names should reflect the clock output signal > names for the device. > > +clock-always-on: 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. Isn't "clocksource" here way too similar to, I don't know, the clocksource framework? Wouln't clock provider be better? > + > + This property is not to be abused. It is only to be used to > + protect platforms from being crippled by gated clocks, not > + as a convenience function to avoid using the framework > + correctly inside device drivers. Disregarding what's stated here, I'm pretty sure that this will actually happen. Where do you place the cursor? Should we create a new driver for our RAM controller, or do we want to use clock-always-on? Do we really want to enforce this if we ever gain a driver that would actually be able to manage its clock (like do we want the CPU clock to never *ever* be gated just because we don't have a cpuidle/hotplug driver yet?) Have you seen the numerous NAK on such approach Mike did? Maxime -- Maxime Ripard, Free Electrons Embedded Linux, Kernel and Android engineering http://free-electrons.com
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