Hi Rob, On Wed, 2016-01-06 at 09:08 -0600, Rob Herring wrote: > On Tue, Jan 05, 2016 at 02:30:18PM +0800, James Liao wrote: > > This patch adds the binding documentation for apmixedsys, bdpsys, > > ethsys, hifsys, imgsys, infracfg, mmsys, pericfg, topckgen and > > vdecsys for Mediatek MT2701. > > > > Signed-off-by: James Liao <jamesjj.liao@xxxxxxxxxxxx> > > [...] > > > diff --git a/Documentation/devicetree/bindings/arm/mediatek/mediatek,bdpsys.txt b/Documentation/devicetree/bindings/arm/mediatek/mediatek,bdpsys.txt > > new file mode 100644 > > index 0000000..4137196 > > --- /dev/null > > +++ b/Documentation/devicetree/bindings/arm/mediatek/mediatek,bdpsys.txt > > @@ -0,0 +1,22 @@ > > +Mediatek bdpsys controller > > +============================ > > + > > +The Mediatek bdpsys controller provides various clocks to the system. > > + > > +Required Properties: > > + > > +- compatible: Should be: > > + - "mediatek,mt2701-bdpsys", "syscon" > > If this block and others only provide clocks, then why do you need > syscon here? If it is more that clocks, then the description is wrong. Sorry for late reply. In bdpsys and other similar subsystems, clock controlling and other feature controlling share the same register space. That means we may have multiple DT nodes with the same reg (register address) property. But it's not a good idea because we may have racing issue when multiple drivers share the same register space. With syscon, drivers that need share the same register base with bdpsys can safely control registers through regmap APIs. These subsystem nodes described in arm/mediatek/ are clock controllers, some of them may be the reset controller at the same time. Other subsystem features will have their own DT nodes and share the same register space by referring to these clock controllers. Best regards, James -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
