On Tue, May 27, 2014 at 8:55 AM, Philipp Zabel <p.zabel@xxxxxxxxxxxxxx> wrote: > For devices which have a complete register for themselves, it is possible to > place them next to the syscon device with overlapping reg ranges. The same is We want to avoid overlapping ranges. > not possible for devices which only occupy bitfields in registers shared with > other users. You are addressing the latter case here? > For devices that are completely controlled by bitfields in the syscon address > range, such as multiplexers or voltage regulators, allow to put child devices > into the syscon device node. > > Signed-off-by: Philipp Zabel <p.zabel@xxxxxxxxxxxxxx> > --- > Documentation/devicetree/bindings/mfd/syscon.txt | 11 +++++++++++ > drivers/mfd/syscon.c | 2 ++ > 2 files changed, 13 insertions(+) > > diff --git a/Documentation/devicetree/bindings/mfd/syscon.txt b/Documentation/devicetree/bindings/mfd/syscon.txt > index fe8150b..a7e11d5 100644 > --- a/Documentation/devicetree/bindings/mfd/syscon.txt > +++ b/Documentation/devicetree/bindings/mfd/syscon.txt > @@ -9,10 +9,21 @@ using a specific compatible value), interrogate the node (or associated > OS driver) to determine the location of the registers, and access the > registers directly. > > +Optionally, devices that are only controlled through single syscon > +registers or bitfields can also be added as child nodes to the syscon > +device node. These devices can implicitly assume their parent node > +as syscon provider without referencing it explicitly via phandle. > +In this case, the syscon node should have #address-cells = <1> and > +#size-cells = <0> and no ranges property. > + I'd like to see an example. What does reg in the child contain? The register address? What if the child device needs 3 bitfields from 3 different registers? It seems to me that you could then want to describe every single bitfield of a block in the DT. That seems like too much information in DT much like trying to describe every single clock in DT. 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
