On Thu, Jan 15, 2015 at 7:55 AM, Mark Rutland <mark.rutland@xxxxxxx> wrote: > On Thu, Jan 15, 2015 at 01:52:01PM +0000, Mark Rutland wrote: >> On Wed, Jan 14, 2015 at 08:58:18PM +0000, Suman Anna wrote: >> > This patch adds the generic common bindings used to represent >> > a hwlock device and use/request locks in a device-tree build. >> > >> > All the platform-specific hwlock driver implementations need the >> > number of locks and associated base id for registering the locks >> > present within the device with the driver core. This base id >> > needs to be unique across multiple IP instances of a hwspinlock >> > device, so that each hwlock can be represented uniquely in a >> > system. >> > >> > The number of locks is represented by 'hwlock-num-locks' property, >> > and the base id is represented by the 'hwlock-base-id' property. >> > The args specifier length is dependent on each vendor-specific >> > implementation and is represented through the '#hwlock-cells' >> > property. Client users need to use the property 'hwlocks' for >> > requesting specific lock(s). >> > >> > Note that the document is named hwlock.txt deliberately to keep >> > it a bit more generic. >> > >> > Cc: Rob Herring <robh+dt@xxxxxxxxxx> >> > Signed-off-by: Suman Anna <s-anna@xxxxxx> >> > --- >> > v7: Revised binding info for hwlock-base-id, it is mandatory now >> > >> > .../devicetree/bindings/hwlock/hwlock.txt | 55 ++++++++++++++++++++++ >> > 1 file changed, 55 insertions(+) >> > create mode 100644 Documentation/devicetree/bindings/hwlock/hwlock.txt >> > >> > diff --git a/Documentation/devicetree/bindings/hwlock/hwlock.txt b/Documentation/devicetree/bindings/hwlock/hwlock.txt >> > new file mode 100644 >> > index 000000000000..8de7aaf878f9 >> > --- /dev/null >> > +++ b/Documentation/devicetree/bindings/hwlock/hwlock.txt >> > @@ -0,0 +1,55 @@ >> > +Generic hwlock bindings >> > +======================= >> > + >> > +Generic bindings that are common to all the hwlock platform specific driver >> > +implementations. >> > + >> > +The validity and need of these common properties may vary from one platform >> > +implementation to another. The platform specific bindings should explicitly >> > +state if an optional property is used. Please also look through the individual >> > +platform specific hwlock binding documentations for identifying the applicable >> > +properties. >> > + >> > +Common properties: >> > +- #hwlock-cells: Specifies the number of cells needed to represent a >> > + specific lock. This property is mandatory for all >> > + platform implementations. >> > +- hwlock-num-locks: Number of locks present in a hwlock device. This >> > + property is needed on hwlock devices, where the number >> > + of supported locks within a hwlock device cannot be >> > + read from a register. >> > +- hwlock-base-id: An unique base Id for the locks for a particular hwlock >> > + device. This property is mandatory for all platform >> > + implementations. >> >> This property makes no sense. The ID encoded in the hwlock cells is >> relative to the instance (identified by phandle), not global. So the DT >> has no global ID space. >> >> Why do you think you need this? > > Having looked at the way this proeprty is used, NAK. > > If you need to carve up a Linux-internal ID space, do that dynamically. > There is no need for this property. Better yet, don't create a Linux ID space for this. Everywhere we have one, we want to get rid of it. Rob -- 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
