Based on kernel version 4.3. Page generated on 2015-11-02 12:46 EST.
1 MIPI DSI (Display Serial Interface) busses 2 ========================================== 3 4 The MIPI Display Serial Interface specifies a serial bus and a protocol for 5 communication between a host and up to four peripherals. This document will 6 define the syntax used to represent a DSI bus in a device tree. 7 8 This document describes DSI bus-specific properties only or defines existing 9 standard properties in the context of the DSI bus. 10 11 Each DSI host provides a DSI bus. The DSI host controller's node contains a 12 set of properties that characterize the bus. Child nodes describe individual 13 peripherals on that bus. 14 15 The following assumes that only a single peripheral is connected to a DSI 16 host. Experience shows that this is true for the large majority of setups. 17 18 DSI host 19 -------- 20 21 In addition to the standard properties and those defined by the parent bus of 22 a DSI host, the following properties apply to a node representing a DSI host. 23 24 Required properties: 25 - #address-cells: The number of cells required to represent an address on the 26 bus. DSI peripherals are addressed using a 2-bit virtual channel number, so 27 a maximum of 4 devices can be addressed on a single bus. Hence the value of 28 this property should be 1. 29 - #size-cells: Should be 0. There are cases where it makes sense to use a 30 different value here. See below. 31 32 DSI peripheral 33 -------------- 34 35 Peripherals are represented as child nodes of the DSI host's node. Properties 36 described here apply to all DSI peripherals, but individual bindings may want 37 to define additional, device-specific properties. 38 39 Required properties: 40 - reg: The virtual channel number of a DSI peripheral. Must be in the range 41 from 0 to 3. 42 43 Some DSI peripherals respond to more than a single virtual channel. In that 44 case two alternative representations can be chosen: 45 - The reg property can take multiple entries, one for each virtual channel 46 that the peripheral responds to. 47 - If the virtual channels that a peripheral responds to are consecutive, the 48 #size-cells can be set to 1. The first cell of each entry in the reg 49 property is the number of the first virtual channel and the second cell is 50 the number of consecutive virtual channels. 51 52 Example 53 ------- 54 55 dsi-host { 56 ... 57 58 #address-cells = <1>; 59 #size-cells = <0>; 60 61 /* peripheral responds to virtual channel 0 */ 62 peripheral@0 { 63 compatible = "..."; 64 reg = <0>; 65 }; 66 67 ... 68 }; 69 70 dsi-host { 71 ... 72 73 #address-cells = <1>; 74 #size-cells = <0>; 75 76 /* peripheral responds to virtual channels 0 and 2 */ 77 peripheral@0 { 78 compatible = "..."; 79 reg = <0, 2>; 80 }; 81 82 ... 83 }; 84 85 dsi-host { 86 ... 87 88 #address-cells = <1>; 89 #size-cells = <1>; 90 91 /* peripheral responds to virtual channels 1, 2 and 3 */ 92 peripheral@1 { 93 compatible = "..."; 94 reg = <1 3>; 95 }; 96 97 ... 98 };