host. Experience shows that this is true for the large majority of setups.
DSI host
---------
+========
In addition to the standard properties and those defined by the parent bus of
a DSI host, the following properties apply to a node representing a DSI host.
- #size-cells: Should be 0. There are cases where it makes sense to use a
different value here. See below.
+Optional properties:
+- clock-master: boolean. 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.
+
DSI peripheral
---------------
+==============
+
+Peripherals with DSI as control bus, or no control bus
+------------------------------------------------------
-Peripherals are represented as child nodes of the DSI host's node. Properties
-described here apply to all DSI peripherals, but individual bindings may want
-to define additional, device-specific properties.
+Peripherals with the DSI bus as the primary control bus, or peripherals with
+no control bus but use the DSI bus to transmit pixel data are represented
+as child nodes of the DSI host's node. Properties described here apply to all
+DSI peripherals, but individual bindings may want to define additional,
+device-specific properties.
Required properties:
- reg: The virtual channel number of a DSI peripheral. Must be in the range
property is the number of the first virtual channel and the second cell is
the number of consecutive virtual channels.
-Example
--------
-
+Peripherals with a different control bus
+----------------------------------------
+
+There are peripherals that have I2C/SPI (or some other non-DSI bus) as the
+primary control bus, but are also connected to a DSI bus (mostly for the data
+path). Connections between such peripherals and a DSI host can be represented
+using the graph bindings [1], [2].
+
+Peripherals that support dual channel DSI
+-----------------------------------------
+
+Peripherals with higher bandwidth requirements can be connected to 2 DSI
+busses. Each DSI bus/channel drives some portion of the pixel data (generally
+left/right half of each line of the display, or even/odd lines of the display).
+The graph bindings should be used to represent the multiple DSI busses that are
+connected to this peripheral. Each DSI host's output endpoint can be linked to
+an input endpoint of the DSI peripheral.
+
+[1] Documentation/devicetree/bindings/graph.txt
+[2] Documentation/devicetree/bindings/media/video-interfaces.txt
+
+Examples
+========
+- (1), (2) and (3) are examples of a DSI host and peripheral on the DSI bus
+ with different virtual channel configurations.
+- (4) is an example of a peripheral on a I2C control bus connected to a
+ DSI host using of-graph bindings.
+- (5) is an example of 2 DSI hosts driving a dual-channel DSI peripheral,
+ which uses I2C as its primary control bus.
+
+1)
dsi-host {
...
...
};
+2)
dsi-host {
...
...
};
+3)
dsi-host {
...
...
};
+
+4)
+ i2c-host {
+ ...
+
+ dsi-bridge@35 {
+ compatible = "...";
+ reg = <0x35>;
+
+ ports {
+ ...
+
+ port {
+ bridge_mipi_in: endpoint {
+ remote-endpoint = <&host_mipi_out>;
+ };
+ };
+ };
+ };
+ };
+
+ dsi-host {
+ ...
+
+ ports {
+ ...
+
+ port {
+ host_mipi_out: endpoint {
+ remote-endpoint = <&bridge_mipi_in>;
+ };
+ };
+ };
+ };
+
+5)
+ i2c-host {
+ dsi-bridge@35 {
+ compatible = "...";
+ reg = <0x35>;
+
+ ports {
+ #address-cells = <1>;
+ #size-cells = <0>;
+
+ port@0 {
+ reg = <0>;
+ dsi0_in: endpoint {
+ remote-endpoint = <&dsi0_out>;
+ };
+ };
+
+ port@1 {
+ reg = <1>;
+ dsi1_in: endpoint {
+ remote-endpoint = <&dsi1_out>;
+ };
+ };
+ };
+ };
+ };
+
+ dsi0-host {
+ ...
+
+ /*
+ * this DSI instance drives the clock for both the host
+ * controllers
+ */
+ clock-master;
+
+ ports {
+ ...
+
+ port {
+ dsi0_out: endpoint {
+ remote-endpoint = <&dsi0_in>;
+ };
+ };
+ };
+ };
+
+ dsi1-host {
+ ...
+
+ ports {
+ ...
+
+ port {
+ dsi1_out: endpoint {
+ remote-endpoint = <&dsi1_in>;
+ };
+ };
+ };
+ };
git.samba.org / sfrench / cifs-2.6.git / blobdiff