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[1/6] dt-bindings: display: add Unisoc's drm master bindings

Message ID 1606746513-30909-2-git-send-email-kevin3.tang@gmail.com (mailing list archive)
State New, archived
Headers show
Series Add Unisoc's drm kms module | expand

Commit Message

Kevin Tang Nov. 30, 2020, 2:28 p.m. UTC 
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: Chunyan Zhang <zhang.lyra@gmail.com>
Signed-off-by: Kevin Tang <kevin.tang@unisoc.com>
---
 .../display/sprd/sprd,display-subsystem.yaml       | 39 ++++++++++++++++++++++
 1 file changed, 39 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/display/sprd/sprd,display-subsystem.yaml

Comments

Kevin Tang Dec. 1, 2020, 7:36 a.m. UTC | #1 
Hi Rob

Rob Herring <robh+dt@kernel.org> 于2020年12月1日周二 上午4:29写道：
>
> On Mon, Nov 30, 2020 at 7:28 AM Kevin Tang <kevin3.tang@gmail.com> wrote:
> >
> > From: Kevin Tang <kevin.tang@unisoc.com>
>
> Once again, DT patches must Cc the DT list if you want them reviewed.
Ok, i will add DT list to my Cc list.
>
> >
> > 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: Chunyan Zhang <zhang.lyra@gmail.com>
> > Signed-off-by: Kevin Tang <kevin.tang@unisoc.com>
> > ---
> >  .../display/sprd/sprd,display-subsystem.yaml       | 39
++++++++++++++++++++++
> >  1 file changed, 39 insertions(+)
> >  create mode 100644
Documentation/devicetree/bindings/display/sprd/sprd,display-subsystem.yaml
> >
> > diff --git
a/Documentation/devicetree/bindings/display/sprd/sprd,display-subsystem.yaml
b/Documentation/devicetree/bindings/display/sprd/sprd,display-subsystem.yaml
> > new file mode 100644
> > index 0000000..9487a39
> > --- /dev/null
> > +++
b/Documentation/devicetree/bindings/display/sprd/sprd,display-subsystem.yaml
> > @@ -0,0 +1,39 @@
> > +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> > +%YAML 1.2
> > +---
> > +$id:
http://devicetree.org/schemas/display/sprd/sprd,display-subsystem.yaml#
> > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > +
> > +title: Unisoc DRM master device
> > +
> > +maintainers:
> > +  - Kevin Tang <kevin.tang@unisoc.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
>
> As I said before, we try to avoid these virtual nodes. Make the DRM
> driver bind to the DPU node.
>
> The case where this might be needed is if you have h/w that's a
> mixture of shared and discrete blocks. I don't see anything here
> matching that.

This is how I understand this sentence: "h/w that's a mixture of shared and
discrete blocks"
We have multiple display controllers and corresponding physical interfaces,
typical dual-screen display scenario
E.g:
1. dpu0 and dpu1 both binding to DSI for dual mipi-dsi display;
2. dpu0 binding to DSI for primary display, and dpu1 binding to DP for
external display;

It looks like this:
dpu0------>MIPI-DSI------>DPHY/CPHY Combo------>Panel0
                        ^
    ----------------|
    |
dpu1------>DisplayPort------>PHY------>Panel1

For DTS like this:
display-subsystem {
compatible = "sprd,display-subsystem";
ports = <&dpu0_out>, <&dpu1_out>;
};

But this is our first time submitting code to the community, following the
suggestions of other reviewers, we only submitted a basic version. Other
virtual nodes and corresponding drivers will be submitted later.
>
> Rob
Rob Herring Dec. 1, 2020, 5:36 p.m. UTC | #2 
On Tue, Dec 1, 2020 at 12:36 AM Kevin Tang <kevin3.tang@gmail.com> wrote:
>
> Hi Rob
>
> Rob Herring <robh+dt@kernel.org> 于2020年12月1日周二 上午4:29写道：
> >
> > On Mon, Nov 30, 2020 at 7:28 AM Kevin Tang <kevin3.tang@gmail.com> wrote:
> > >
> > > From: Kevin Tang <kevin.tang@unisoc.com>
> >
> > Once again, DT patches must Cc the DT list if you want them reviewed.
> Ok, i will add DT list to my Cc list.
> >
> > >
> > > 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: Chunyan Zhang <zhang.lyra@gmail.com>
> > > Signed-off-by: Kevin Tang <kevin.tang@unisoc.com>
> > > ---
> > >  .../display/sprd/sprd,display-subsystem.yaml       | 39 ++++++++++++++++++++++
> > >  1 file changed, 39 insertions(+)
> > >  create mode 100644 Documentation/devicetree/bindings/display/sprd/sprd,display-subsystem.yaml
> > >
> > > diff --git a/Documentation/devicetree/bindings/display/sprd/sprd,display-subsystem.yaml b/Documentation/devicetree/bindings/display/sprd/sprd,display-subsystem.yaml
> > > new file mode 100644
> > > index 0000000..9487a39
> > > --- /dev/null
> > > +++ b/Documentation/devicetree/bindings/display/sprd/sprd,display-subsystem.yaml
> > > @@ -0,0 +1,39 @@
> > > +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> > > +%YAML 1.2
> > > +---
> > > +$id: http://devicetree.org/schemas/display/sprd/sprd,display-subsystem.yaml#
> > > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > > +
> > > +title: Unisoc DRM master device
> > > +
> > > +maintainers:
> > > +  - Kevin Tang <kevin.tang@unisoc.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
> >
> > As I said before, we try to avoid these virtual nodes. Make the DRM
> > driver bind to the DPU node.
> >
> > The case where this might be needed is if you have h/w that's a
> > mixture of shared and discrete blocks. I don't see anything here
> > matching that.
>
> This is how I understand this sentence: "h/w that's a mixture of shared and discrete blocks"
> We have multiple display controllers and corresponding physical interfaces, typical dual-screen display scenario
> E.g:
> 1. dpu0 and dpu1 both binding to DSI for dual mipi-dsi display;
> 2. dpu0 binding to DSI for primary display, and dpu1 binding to DP for external display;
>
> It looks like this:
> dpu0------>MIPI-DSI------>DPHY/CPHY Combo------>Panel0
>                         ^
>     ----------------|
>     |
> dpu1------>DisplayPort------>PHY------>Panel1
>
> For DTS like this:
> display-subsystem {
> compatible = "sprd,display-subsystem";
> ports = <&dpu0_out>, <&dpu1_out>;
> };

Yeah, this would be one such case. Just make this scenario clear in
commit message.

Rob
diff mbox series

Patch

diff --git a/Documentation/devicetree/bindings/display/sprd/sprd,display-subsystem.yaml b/Documentation/devicetree/bindings/display/sprd/sprd,display-subsystem.yaml
new file mode 100644
index 0000000..9487a39
--- /dev/null
+++ b/Documentation/devicetree/bindings/display/sprd/sprd,display-subsystem.yaml
@@ -0,0 +1,39 @@ 
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/display/sprd/sprd,display-subsystem.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Unisoc DRM master device
+
+maintainers:
+  - Kevin Tang <kevin.tang@unisoc.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:
+    $ref: /schemas/types.yaml#/definitions/phandle-array
+    description:
+      Should contain a list of phandles pointing to display interface port
+      of DPU devices.
+
+required:
+  - compatible
+  - ports
+
+additionalProperties: false
+
+examples:
+  - |
+    display-subsystem {
+        compatible = "sprd,display-subsystem";
+        ports = <&dpu_out>;
+    };
+