[PATCH 1/3 v3] drm/panel: Add generic DSI panel YAML bindings
linus.walleij at linaro.org
Fri Oct 18 18:24:44 UTC 2019
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 at vger.kernel.org
Suggested-by: Rob Herring <robh at kernel.org>
Signed-off-by: Linus Walleij <linus.walleij at linaro.org>
- 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?
- 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
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
@@ -0,0 +1,58 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+title: Common Properties for DSI Display Panels
+ - Linus Walleij <linus.walleij at linaro.org>
+ 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
+ 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.
+ pattern: "^dsi-controller(@[0-9a-f]+)?$"
+ const: 1
+ const: 0
+ type: object
+ const: 0
+ Only one panel can be connected to each DSI controller, but for
+ historical reasons, the reg property must be specified, as the
+ DSI controller can contain other child nodes, and operating
+ systems will identify which child node is the panel by looking
+ for the reg property. It should however always be set to 0.
+ type: boolean
+ The best option is usually to run a panel in command mode, as this
+ gives better control over the panel hardware. However for different
+ reasons like broken hardware, missing features or testing, it may be
+ useful to be able to force a command mode-capable panel into video
More information about the dri-devel