xref: /freebsd/sys/contrib/device-tree/Bindings/display/bridge/megachips-stdpxxxx-ge-b850v3-fw.txt (revision dd41de95a84d979615a2ef11df6850622bf6184e)
1Drivers for the second video output of the GE B850v3:
2   STDP4028-ge-b850v3-fw bridges (LVDS-DP)
3   STDP2690-ge-b850v3-fw bridges (DP-DP++)
4
5The video processing pipeline on the second output on the GE B850v3:
6
7   Host -> LVDS|--(STDP4028)--|DP -> DP|--(STDP2690)--|DP++ -> Video output
8
9Each bridge has a dedicated flash containing firmware for supporting the custom
10design. The result is that, in this design, neither the STDP4028 nor the
11STDP2690 behave as the stock bridges would. The compatible strings include the
12suffix "-ge-b850v3-fw" to make it clear that the driver is for the bridges with
13the firmware specific for the GE B850v3.
14
15The hardware do not provide control over the video processing pipeline, as the
16two bridges behaves as a single one. The only interfaces exposed by the
17hardware are EDID, HPD, and interrupts.
18
19stdp4028-ge-b850v3-fw required properties:
20  - compatible : "megachips,stdp4028-ge-b850v3-fw"
21  - reg : I2C bus address
22  - interrupts : one interrupt should be described here, as in
23    <0 IRQ_TYPE_LEVEL_HIGH>
24  - ports : One input port(reg = <0>) and one output port(reg = <1>)
25
26stdp2690-ge-b850v3-fw required properties:
27    compatible : "megachips,stdp2690-ge-b850v3-fw"
28  - reg : I2C bus address
29  - ports : One input port(reg = <0>) and one output port(reg = <1>)
30
31Example:
32
33&mux2_i2c2 {
34	clock-frequency = <100000>;
35
36	stdp4028@73 {
37		compatible = "megachips,stdp4028-ge-b850v3-fw";
38		#address-cells = <1>;
39		#size-cells = <0>;
40
41		reg = <0x73>;
42
43		interrupt-parent = <&gpio2>;
44		interrupts = <0 IRQ_TYPE_LEVEL_HIGH>;
45
46		ports {
47			#address-cells = <1>;
48			#size-cells = <0>;
49
50			port@0 {
51				reg = <0>;
52				stdp4028_in: endpoint {
53					remote-endpoint = <&lvds0_out>;
54				};
55			};
56			port@1 {
57				reg = <1>;
58				stdp4028_out: endpoint {
59					remote-endpoint = <&stdp2690_in>;
60				};
61			};
62		};
63	};
64
65	stdp2690@72 {
66		compatible = "megachips,stdp2690-ge-b850v3-fw";
67		#address-cells = <1>;
68		#size-cells = <0>;
69
70		reg = <0x72>;
71
72		ports {
73			#address-cells = <1>;
74			#size-cells = <0>;
75
76			port@0 {
77				reg = <0>;
78				stdp2690_in: endpoint {
79					remote-endpoint = <&stdp4028_out>;
80				};
81			};
82
83			port@1 {
84				reg = <1>;
85				stdp2690_out: endpoint {
86					/* Connector for external display */
87				};
88			};
89		};
90	};
91};
92