From mboxrd@z Thu Jan 1 00:00:00 1970 From: robh+dt@kernel.org (Rob Herring) Date: Wed, 20 Apr 2016 09:04:39 -0500 Subject: [PATCH v2 2/2] Documentation: devicetree: Add PL310 PM bindings In-Reply-To: <20160419224122.GE19428@n2100.arm.linux.org.uk> References: <1456265019-23900-1-git-send-email-brad.mouring@ni.com> <1461015411-14000-1-git-send-email-brad.mouring@ni.com> <1461015411-14000-3-git-send-email-brad.mouring@ni.com> <20160419224122.GE19428@n2100.arm.linux.org.uk> Message-ID: To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Tue, Apr 19, 2016 at 5:41 PM, Russell King - ARM Linux wrote: > On Tue, Apr 19, 2016 at 04:38:14PM -0500, Rob Herring wrote: >> On Mon, Apr 18, 2016 at 4:36 PM, Brad Mouring wrote: >> > Document the DT bindings for controlling ARM PL310 Power Control >> > settings. >> > >> > Signed-off-by: Brad Mouring >> >> What happened to Josh's ack? >> >> > --- >> > Documentation/devicetree/bindings/arm/l2c2x0.txt | 4 ++++ >> > 1 file changed, 4 insertions(+) >> > >> > diff --git a/Documentation/devicetree/bindings/arm/l2c2x0.txt b/Documentation/devicetree/bindings/arm/l2c2x0.txt >> > index fe0398c..c1c756e 100644 >> > --- a/Documentation/devicetree/bindings/arm/l2c2x0.txt >> > +++ b/Documentation/devicetree/bindings/arm/l2c2x0.txt >> > @@ -84,6 +84,10 @@ Optional properties: >> > - prefetch-instr : Instruction prefetch. Value: <0> (forcibly disable), >> > <1> (forcibly enable), property absent (retain settings set by >> > firmware) >> > +- arm,dynamic-clock-gating : L2 dynamic clock gating. Value: <0> (forcibly >> > + disable), <1> or property absent (forcibly enable) >> > +- arm,standby-mode: L2 standby mode enable. Value <0> (forcibly disable), >> > + <1> or property absent (forcibly enable) >> >> What happened to "retain settings set by firmware"? > > I said we shouldn't. Current behaviour is that we enable these features, > and moving to missing-means-retain means that everything today ends up > with these features disabled. IOW, it's yet another change of actual > behaviour that every platform would see. Right, but then the properties are different from prefetch-instr and others IIRC. We're letting the OS define the binding. If BSD doesn't enable these settings currently, then there is a mismatch between the binding and actual behavior. Saying "retain firmware settings" also defines specific OS behavior. I think absent should mean OS is free to do whatever it wants which could be retain firmware settings, enable or disable. In other words, it is undefined as this ship has already sailed. Rob