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diff --git a/Documentation/devicetree/bindings/media/video-interfaces.txt b/Documentation/devicetree/bindings/media/video-interfaces.txt new file mode 100644 index 000000000000..e022d2dc4962 --- /dev/null +++ b/Documentation/devicetree/bindings/media/video-interfaces.txt @@ -0,0 +1,228 @@ +Common bindings for video receiver and transmitter interfaces + +General concept +--------------- + +Video data pipelines usually consist of external devices, e.g. camera sensors, +controlled over an I2C, SPI or UART bus, and SoC internal IP blocks, including +video DMA engines and video data processors. + +SoC internal blocks are described by DT nodes, placed similarly to other SoC +blocks. External devices are represented as child nodes of their respective +bus controller nodes, e.g. I2C. + +Data interfaces on all video devices are described by their child 'port' nodes. +Configuration of a port depends on other devices participating in the data +transfer and is described by 'endpoint' subnodes. + +device { + ... + ports { + #address-cells = <1>; + #size-cells = <0>; + + port@0 { + ... + endpoint@0 { ... }; + endpoint@1 { ... }; + }; + port@1 { ... }; + }; +}; + +If a port can be configured to work with more than one remote device on the same +bus, an 'endpoint' child node must be provided for each of them. If more than +one port is present in a device node or there is more than one endpoint at a +port, or port node needs to be associated with a selected hardware interface, +a common scheme using '#address-cells', '#size-cells' and 'reg' properties is +used. + +All 'port' nodes can be grouped under optional 'ports' node, which allows to +specify #address-cells, #size-cells properties independently for the 'port' +and 'endpoint' nodes and any child device nodes a device might have. + +Two 'endpoint' nodes are linked with each other through their 'remote-endpoint' +phandles. An endpoint subnode of a device contains all properties needed for +configuration of this device for data exchange with other device. In most +cases properties at the peer 'endpoint' nodes will be identical, however they +might need to be different when there is any signal modifications on the bus +between two devices, e.g. there are logic signal inverters on the lines. + +It is allowed for multiple endpoints at a port to be active simultaneously, +where supported by a device. For example, in case where a data interface of +a device is partitioned into multiple data busses, e.g. 16-bit input port +divided into two separate ITU-R BT.656 8-bit busses. In such case bus-width +and data-shift properties can be used to assign physical data lines to each +endpoint node (logical bus). + + +Required properties +------------------- + +If there is more than one 'port' or more than one 'endpoint' node or 'reg' +property is present in port and/or endpoint nodes the following properties +are required in a relevant parent node: + + - #address-cells : number of cells required to define port/endpoint + identifier, should be 1. + - #size-cells : should be zero. + +Optional endpoint properties +---------------------------- + +- remote-endpoint: phandle to an 'endpoint' subnode of a remote device node. +- slave-mode: a boolean property indicating that the link is run in slave mode. + The default when this property is not specified is master mode. In the slave + mode horizontal and vertical synchronization signals are provided to the + slave device (data source) by the master device (data sink). In the master + mode the data source device is also the source of the synchronization signals. +- bus-width: number of data lines actively used, valid for the parallel busses. +- data-shift: on the parallel data busses, if bus-width is used to specify the + number of data lines, data-shift can be used to specify which data lines are + used, e.g. "bus-width=<8>; data-shift=<2>;" means, that lines 9:2 are used. +- hsync-active: active state of the HSYNC signal, 0/1 for LOW/HIGH respectively. +- vsync-active: active state of the VSYNC signal, 0/1 for LOW/HIGH respectively. + Note, that if HSYNC and VSYNC polarities are not specified, embedded + synchronization may be required, where supported. +- data-active: similar to HSYNC and VSYNC, specifies data line polarity. +- field-even-active: field signal level during the even field data transmission. +- pclk-sample: sample data on rising (1) or falling (0) edge of the pixel clock + signal. +- data-lanes: an array of physical data lane indexes. Position of an entry + determines the logical lane number, while the value of an entry indicates + physical lane, e.g. for 2-lane MIPI CSI-2 bus we could have + "data-lanes = <1 2>;", assuming the clock lane is on hardware lane 0. + This property is valid for serial busses only (e.g. MIPI CSI-2). +- clock-lanes: an array of physical clock lane indexes. Position of an entry + determines the logical lane number, while the value of an entry indicates + physical lane, e.g. for a MIPI CSI-2 bus we could have "clock-lanes = <0>;", + which places the clock lane on hardware lane 0. This property is valid for + serial busses only (e.g. MIPI CSI-2). Note that for the MIPI CSI-2 bus this + array contains only one entry. +- clock-noncontinuous: a boolean property to allow MIPI CSI-2 non-continuous + clock mode. + + +Example +------- + +The example snippet below describes two data pipelines. ov772x and imx074 are +camera sensors with a parallel and serial (MIPI CSI-2) video bus respectively. +Both sensors are on the I2C control bus corresponding to the i2c0 controller +node. ov772x sensor is linked directly to the ceu0 video host interface. +imx074 is linked to ceu0 through the MIPI CSI-2 receiver (csi2). ceu0 has a +(single) DMA engine writing captured data to memory. ceu0 node has a single +'port' node which may indicate that at any time only one of the following data +pipelines can be active: ov772x -> ceu0 or imx074 -> csi2 -> ceu0. + + ceu0: ceu@0xfe910000 { + compatible = "renesas,sh-mobile-ceu"; + reg = <0xfe910000 0xa0>; + interrupts = <0x880>; + + mclk: master_clock { + compatible = "renesas,ceu-clock"; + #clock-cells = <1>; + clock-frequency = <50000000>; /* Max clock frequency */ + clock-output-names = "mclk"; + }; + + port { + #address-cells = <1>; + #size-cells = <0>; + + /* Parallel bus endpoint */ + ceu0_1: endpoint@1 { + reg = <1>; /* Local endpoint # */ + remote = <&ov772x_1_1>; /* Remote phandle */ + bus-width = <8>; /* Used data lines */ + data-shift = <2>; /* Lines 9:2 are used */ + + /* If hsync-active/vsync-active are missing, + embedded BT.656 sync is used */ + hsync-active = <0>; /* Active low */ + vsync-active = <0>; /* Active low */ + data-active = <1>; /* Active high */ + pclk-sample = <1>; /* Rising */ + }; + + /* MIPI CSI-2 bus endpoint */ + ceu0_0: endpoint@0 { + reg = <0>; + remote = <&csi2_2>; + }; + }; + }; + + i2c0: i2c@0xfff20000 { + ... + ov772x_1: camera@0x21 { + compatible = "omnivision,ov772x"; + reg = <0x21>; + vddio-supply = <®ulator1>; + vddcore-supply = <®ulator2>; + + clock-frequency = <20000000>; + clocks = <&mclk 0>; + clock-names = "xclk"; + + port { + /* With 1 endpoint per port no need for addresses. */ + ov772x_1_1: endpoint { + bus-width = <8>; + remote-endpoint = <&ceu0_1>; + hsync-active = <1>; + vsync-active = <0>; /* Who came up with an + inverter here ?... */ + data-active = <1>; + pclk-sample = <1>; + }; + }; + }; + + imx074: camera@0x1a { + compatible = "sony,imx074"; + reg = <0x1a>; + vddio-supply = <®ulator1>; + vddcore-supply = <®ulator2>; + + clock-frequency = <30000000>; /* Shared clock with ov772x_1 */ + clocks = <&mclk 0>; + clock-names = "sysclk"; /* Assuming this is the + name in the datasheet */ + port { + imx074_1: endpoint { + clock-lanes = <0>; + data-lanes = <1 2>; + remote-endpoint = <&csi2_1>; + }; + }; + }; + }; + + csi2: csi2@0xffc90000 { + compatible = "renesas,sh-mobile-csi2"; + reg = <0xffc90000 0x1000>; + interrupts = <0x17a0>; + #address-cells = <1>; + #size-cells = <0>; + + port@1 { + compatible = "renesas,csi2c"; /* One of CSI2I and CSI2C. */ + reg = <1>; /* CSI-2 PHY #1 of 2: PHY_S, + PHY_M has port address 0, + is unused. */ + csi2_1: endpoint { + clock-lanes = <0>; + data-lanes = <2 1>; + remote-endpoint = <&imx074_1>; + }; + }; + port@2 { + reg = <2>; /* port 2: link to the CEU */ + + csi2_2: endpoint { + remote-endpoint = <&ceu0_0>; + }; + }; + }; |
