On Fri, Oct 18, 2019 at 1:24 PM Linus Walleij linus.walleij@linaro.org wrote:
This adds a starting point for processing and defining generic bindings used by DSI panels. We just define one single bool property to force the panel into video mode for now.
Cc: devicetree@vger.kernel.org Suggested-by: Rob Herring robh@kernel.org Signed-off-by: Linus Walleij linus.walleij@linaro.org
ChangeLog v2->v3:
- Make a more complete DSI panel binding including the controller and its address-cells and size-cells and a pattern for the panel nodes. The panel is one per DSI master, the reg property is compulsory but should always be 0 (as far as I can tell) as only one panel can be connected. The bus doesn't really have any addresses for the panel, the address/reg notation seems to be cargo-culted from the port graphs and is not necessary to parse some device trees, it is used to tell whether the node is a panel or not rather than any addressing.
- I have no idea how many displays you can daisychain on a single DSI master, I just guess 15 will be enough. The MIPI-specs are memberwalled. Someone who knows can tell perhaps?
ChangeLog v1->v2:
- New patch after feedback.
.../display/panel/panel-dsi-common.yaml | 58 +++++++++++++++++++ 1 file changed, 58 insertions(+) create mode 100644 Documentation/devicetree/bindings/display/panel/panel-dsi-common.yaml
Perhaps should be display/dsi-controller.yaml now?
diff --git a/Documentation/devicetree/bindings/display/panel/panel-dsi-common.yaml b/Documentation/devicetree/bindings/display/panel/panel-dsi-common.yaml new file mode 100644 index 000000000000..d63f597eff9c --- /dev/null +++ b/Documentation/devicetree/bindings/display/panel/panel-dsi-common.yaml @@ -0,0 +1,58 @@ +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) +%YAML 1.2 +--- +$id: http://devicetree.org/schemas/display/panel/panel-dsi-common.yaml# +$schema: http://devicetree.org/meta-schemas/core.yaml#
+title: Common Properties for DSI Display Panels
+maintainers:
- Linus Walleij linus.walleij@linaro.org
+description: |
- This document defines device tree properties common to DSI, Display
- Serial Interface panels. It doesn't constitute a device tree binding
- specification by itself but is meant to be referenced by device tree
- bindings.
- When referenced from panel device tree bindings the properties defined in
- this document are defined as follows. The panel device tree bindings are
- responsible for defining whether each property is required or optional.
- Notice: this binding concerns DSI panels connected directly to a master
- without any intermediate port graph to the panel. Each DSI master
- can control exactly one panel. They should all just have a node "panel"
- for their panel with their reg-property set to 0.
+properties:
- $nodename:
- pattern: "^dsi-controller(@[0-9a-f]+)?$"
You're assuming a certain unit-address format when a dsi-controller could be on any bus. So use '^dsi-controller(@.*)?$
- "#address-cells":
- const: 1
- "#size-cells":
- const: 0
+patternProperties:
- "^panel$":
But here we want to define the unit-address format. The address is the virtual channel # which can be 0-3:
^panel@[0-3]$
- type: object
- properties:
reg:const: 0
minimum: 0 maximum: 3
description:Only one panel can be connected to each DSI controller, but for
I thought it was up to 4 virtual channels?
historical reasons, the reg property must be specified, as theDSI controller can contain other child nodes, and operatingsystems will identify which child node is the panel by lookingfor the reg property. It should however always be set to 0.enforce-video-mode:type: booleandescription:The best option is usually to run a panel in command mode, as thisgives better control over the panel hardware. However for differentreasons like broken hardware, missing features or testing, it may beuseful to be able to force a command mode-capable panel into videomode.
'reg' should be required?
Rob