On Thu, Oct 24, 2019 at 01:43:03PM +0200, Linus Walleij 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@xxxxxxxxxxxxxxx > Suggested-by: Rob Herring <robh@xxxxxxxxxx> > Signed-off-by: Linus Walleij <linus.walleij@xxxxxxxxxx> > --- > ChangeLog v3->v4: > - Rename into display/dsi-controller.yaml > - Require a virtual channel number for the DSI panel, as > DSI have this 2-bit virtual address field. > - Bring in some but not all properties from the existing MIPI > DSI bindings. This schema can be used with simpler panels but > not complex panels with multiple virtual channels for the > moment. Let's handle it when we get there. > - Add an example. A broken example... > 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. > --- > .../bindings/display/dsi-controller.yaml | 88 +++++++++++++++++++ > 1 file changed, 88 insertions(+) > create mode 100644 Documentation/devicetree/bindings/display/dsi-controller.yaml > > diff --git a/Documentation/devicetree/bindings/display/dsi-controller.yaml b/Documentation/devicetree/bindings/display/dsi-controller.yaml > new file mode 100644 > index 000000000000..2a6d872a40c5 > --- /dev/null > +++ b/Documentation/devicetree/bindings/display/dsi-controller.yaml > @@ -0,0 +1,88 @@ > +# 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@xxxxxxxxxx> > + > +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: > + $nodename: > + pattern: "^dsi-controller(@.*)?$" > + > + "#address-cells": > + const: 1 > + > + "#size-cells": > + const: 0 > + > +patternProperties: > + "^panel@[0-3]$": > + type: object > + > + properties: > + reg: > + minimum: 0 > + maximum: 3 > + description: > + The virtual channel number of a DSI peripheral. Must be in the range > + from 0 to 3, as DSI uses a 2-bit addressing scheme. Some DSI > + peripherals respond to more than a single virtual channel. In that > + case the reg property can take multiple entries, one for each virtual > + channel that the peripheral responds to. > + > + clock-master: > + type: boolean > + description: > + Should be enabled if the host is being used in conjunction with > + another DSI host to drive the same peripheral. Hardware supporting > + such a configuration generally requires the data on both the busses > + to be driven by the same clock. Only the DSI host instance > + controlling this clock should contain this property. > + > + enforce-video-mode: > + type: boolean > + description: > + 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 > + mode. > + > + required: > + - reg > + > +examples: > + - | > + dsi-controller@55aa55aa { > + compatible = "acme,foo"; Eventually, I want to start reporting if compatible strings aren't documented (i.e. matched to a schema). This will break then... > + reg = <0x55aa55aa>; This will fail because a size cell is expected. I'd just drop both properties here. A 'dsi-controller' node name is enough to select this schema. > + #address-cells = <1>; > + #size-cells = <0>; > + panel@0 { > + compatible = "acme,bar"; Just pick a real one. (Or drop the example because the binding for the real panel will have the same example). > + reg = <0>; > + vddi-supply = <&foo>; > + reset-gpios = <&foo_gpio 0 GPIO_ACTIVE_LOW>; > + }; > + }; > + > +... > -- > 2.21.0 >
