On Fri, Feb 28, 2020 at 12:50 AM Rob Herring <robh+dt@kernel.org> wrote:

> On Wed, Feb 26, 2020 at 3:46 AM Kevin Tang <kevin3.tang@gmail.com> wrote:
> >
> > From: Kevin Tang <kevin.tang@unisoc.com>
> >
> > The Unisoc DRM master device is a virtual device needed to list all
> > DPU devices or other display interface nodes that comprise the
> > graphics subsystem
> >
> > Cc: Orson Zhai <orsonzhai@gmail.com>
> > Cc: Baolin Wang <baolin.wang@linaro.org>
> > Cc: Chunyan Zhang <zhang.lyra@gmail.com>
> > Signed-off-by: Kevin Tang <kevin.tang@unisoc.com>
> > ---
> >  .../devicetree/bindings/display/sprd/drm.yaml      | 36
> ++++++++++++++++++++++
> >  1 file changed, 36 insertions(+)
> >  create mode 100644
> Documentation/devicetree/bindings/display/sprd/drm.yaml
> >
> > diff --git a/Documentation/devicetree/bindings/display/sprd/drm.yaml
> b/Documentation/devicetree/bindings/display/sprd/drm.yaml
> > new file mode 100644
> > index 0000000..b5792c0
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/display/sprd/drm.yaml
> > @@ -0,0 +1,36 @@
> > +# SPDX-License-Identifier: GPL-2.0
> > +%YAML 1.2
> > +---
> > +$id: http://devicetree.org/schemas/display/sprd/drm.yaml#
> > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > +
> > +title: Unisoc DRM master device
> > +
> > +maintainers:
> > +  - Mark Rutland <mark.rutland@arm.com>
> > +
> > +description: |
> > +  The Unisoc DRM master device is a virtual device needed to list all
> > +  DPU devices or other display interface nodes that comprise the
> > +  graphics subsystem.
> > +
> > +properties:
> > +  compatible:
> > +    const: sprd,display-subsystem
> > +
> > +  ports:
> > +    description:
> > +      Should contain a list of phandles pointing to display interface
> port
> > +      of DPU devices.
> > +
> > +required:
> > +  - compatible
> > +  - ports
> > +
> > +examples:
> > +  - |
> > +    display-subsystem {
> > +        compatible = "sprd,display-subsystem";
> > +        ports = <&dpu_out>;
>
> We try to avoid these virtual nodes and bind with actual h/w nodes.
> Can you have more than one DPU and if so does it need to be a single
> DRM driver instance?
>
I don't really understand what you mean, so reply as I understand...
"dpu_out" node is the real h/w node, defined on dpu.yaml
Yeah, we will be have multi DPU

>
> Rob
>