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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 000000000..3920f25a9 --- /dev/null +++ b/Documentation/devicetree/bindings/media/video-interfaces.txt @@ -0,0 +1,639 @@ +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). + +Documenting bindings for devices +-------------------------------- + +All required and optional bindings the device supports shall be explicitly +documented in device DT binding documentation. This also includes port and +endpoint nodes for the device, including unit-addresses and reg properties where +relevant. + +Please also see Documentation/devicetree/bindings/graph.txt . + +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 properties +------------------- + +- flash-leds: An array of phandles, each referring to a flash LED, a sub-node + of the LED driver device node. + +- lens-focus: A phandle to the node of the focus lens controller. + +- rotation: The camera rotation is expressed as the angular difference in + degrees between two reference systems, one relative to the camera module, and + one defined on the external world scene to be captured when projected on the + image sensor pixel array. + + A camera sensor has a 2-dimensional reference system 'Rc' defined by + its pixel array read-out order. The origin is set to the first pixel + being read out, the X-axis points along the column read-out direction + towards the last columns, and the Y-axis along the row read-out + direction towards the last row. + + A typical example for a sensor with a 2592x1944 pixel array matrix + observed from the front is: + + 2591 X-axis 0 + <------------------------+ 0 + .......... ... ..........! + .......... ... ..........! Y-axis + ... ! + .......... ... ..........! + .......... ... ..........! 1943 + V + + The external world scene reference system 'Rs' is a 2-dimensional + reference system on the focal plane of the camera module. The origin is + placed on the top-left corner of the visible scene, the X-axis points + towards the right, and the Y-axis points towards the bottom of the + scene. The top, bottom, left and right directions are intentionally not + defined and depend on the environment in which the camera is used. + + A typical example of a (very common) picture of a shark swimming from + left to right, as seen from the camera, is: + + 0 X-axis + 0 +-------------------------------------> + ! + ! + ! + ! |\____)\___ + ! ) _____ __`< + ! |/ )/ + ! + ! + ! + V + Y-axis + + with the reference system 'Rs' placed on the camera focal plane: + + ¸.·˙! + ¸.·˙ ! + _ ¸.·˙ ! + +-/ \-+¸.·˙ ! + | (o) | ! Camera focal plane + +-----+˙·.¸ ! + ˙·.¸ ! + ˙·.¸ ! + ˙·.¸! + + When projected on the sensor's pixel array, the image and the associated + reference system 'Rs' are typically (but not always) inverted, due to + the camera module's lens optical inversion effect. + + Assuming the above represented scene of the swimming shark, the lens + inversion projects the scene and its reference system onto the sensor + pixel array, seen from the front of the camera sensor, as follows: + + Y-axis + ^ + ! + ! + ! + ! |\_____)\__ + ! ) ____ ___.< + ! |/ )/ + ! + ! + ! + 0 +-------------------------------------> + 0 X-axis + + Note the shark being upside-down. + + The resulting projected reference system is named 'Rp'. + + The camera rotation property is then defined as the angular difference + in the counter-clockwise direction between the camera reference system + 'Rc' and the projected scene reference system 'Rp'. It is expressed in + degrees as a number in the range [0, 360[. + + Examples + + 0 degrees camera rotation: + + + Y-Rp + ^ + Y-Rc ! + ^ ! + ! ! + ! ! + ! ! + ! ! + ! ! + ! ! + ! ! + ! 0 +-------------------------------------> + ! 0 X-Rp + 0 +-------------------------------------> + 0 X-Rc + + + X-Rc 0 + <------------------------------------+ 0 + X-Rp 0 ! + <------------------------------------+ 0 ! + ! ! + ! ! + ! ! + ! ! + ! ! + ! ! + ! ! + ! V + ! Y-Rc + V + Y-Rp + + 90 degrees camera rotation: + + 0 Y-Rc + 0 +--------------------> + ! Y-Rp + ! ^ + ! ! + ! ! + ! ! + ! ! + ! ! + ! ! + ! ! + ! ! + ! ! + ! 0 +-------------------------------------> + ! 0 X-Rp + ! + ! + ! + ! + V + X-Rc + + 180 degrees camera rotation: + + 0 + <------------------------------------+ 0 + X-Rc ! + Y-Rp ! + ^ ! + ! ! + ! ! + ! ! + ! ! + ! ! + ! ! + ! V + ! Y-Rc + 0 +-------------------------------------> + 0 X-Rp + + 270 degrees camera rotation: + + 0 Y-Rc + 0 +--------------------> + ! 0 + ! <-----------------------------------+ 0 + ! X-Rp ! + ! ! + ! ! + ! ! + ! ! + ! ! + ! ! + ! ! + ! ! + ! V + ! Y-Rp + ! + ! + ! + ! + V + X-Rc + + + Example one - Webcam + + A camera module installed on the user facing part of a laptop screen + casing used for video calls. The captured images are meant to be + displayed in landscape mode (width > height) on the laptop screen. + + The camera is typically mounted upside-down to compensate the lens + optical inversion effect: + + Y-Rp + Y-Rc ^ + ^ ! + ! ! + ! ! |\_____)\__ + ! ! ) ____ ___.< + ! ! |/ )/ + ! ! + ! ! + ! ! + ! 0 +-------------------------------------> + ! 0 X-Rp + 0 +-------------------------------------> + 0 X-Rc + + The two reference systems are aligned, the resulting camera rotation is + 0 degrees, no rotation correction needs to be applied to the resulting + image once captured to memory buffers to correctly display it to users: + + +--------------------------------------+ + ! ! + ! ! + ! ! + ! |\____)\___ ! + ! ) _____ __`< ! + ! |/ )/ ! + ! ! + ! ! + ! ! + +--------------------------------------+ + + If the camera sensor is not mounted upside-down to compensate for the + lens optical inversion, the two reference systems will not be aligned, + with 'Rp' being rotated 180 degrees relatively to 'Rc': + + + X-Rc 0 + <------------------------------------+ 0 + ! + Y-Rp ! + ^ ! + ! ! + ! |\_____)\__ ! + ! ) ____ ___.< ! + ! |/ )/ ! + ! ! + ! ! + ! V + ! Y-Rc + 0 +-------------------------------------> + 0 X-Rp + + The image once captured to memory will then be rotated by 180 degrees: + + +--------------------------------------+ + ! ! + ! ! + ! ! + ! __/(_____/| ! + ! >.___ ____ ( ! + ! \( \| ! + ! ! + ! ! + ! ! + +--------------------------------------+ + + A software rotation correction of 180 degrees should be applied to + correctly display the image: + + +--------------------------------------+ + ! ! + ! ! + ! ! + ! |\____)\___ ! + ! ) _____ __`< ! + ! |/ )/ ! + ! ! + ! ! + ! ! + +--------------------------------------+ + + Example two - Phone camera + + A camera installed on the back side of a mobile device facing away from + the user. The captured images are meant to be displayed in portrait mode + (height > width) to match the device screen orientation and the device + usage orientation used when taking the picture. + + The camera sensor is typically mounted with its pixel array longer side + aligned to the device longer side, upside-down mounted to compensate for + the lens optical inversion effect: + + 0 Y-Rc + 0 +--------------------> + ! Y-Rp + ! ^ + ! ! + ! ! + ! ! + ! ! |\_____)\__ + ! ! ) ____ ___.< + ! ! |/ )/ + ! ! + ! ! + ! ! + ! 0 +-------------------------------------> + ! 0 X-Rp + ! + ! + ! + ! + V + X-Rc + + The two reference systems are not aligned and the 'Rp' reference + system is rotated by 90 degrees in the counter-clockwise direction + relatively to the 'Rc' reference system. + + The image once captured to memory will be rotated: + + +-------------------------------------+ + | _ _ | + | \ / | + | | | | + | | | | + | | > | + | < | | + | | | | + | . | + | V | + +-------------------------------------+ + + A correction of 90 degrees in counter-clockwise direction has to be + applied to correctly display the image in portrait mode on the device + screen: + + +--------------------+ + | | + | | + | | + | | + | | + | | + | |\____)\___ | + | ) _____ __`< | + | |/ )/ | + | | + | | + | | + | | + | | + +--------------------+ + +- orientation: The orientation of a device (typically an image sensor or a flash + LED) describing its mounting position relative to the usage orientation of the + system where the device is installed on. + Possible values are: + 0 - Front. The device is mounted on the front facing side of the system. + For mobile devices such as smartphones, tablets and laptops the front side is + the user facing side. + 1 - Back. The device is mounted on the back side of the system, which is + defined as the opposite side of the front facing one. + 2 - External. The device is not attached directly to the system but is + attached in a way that allows it to move freely. + +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-type: data bus type. Possible values are: + 1 - MIPI CSI-2 C-PHY + 2 - MIPI CSI1 + 3 - CCP2 + 4 - MIPI CSI-2 D-PHY + 5 - Parallel + 6 - Bt.656 +- 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. +- data-enable-active: similar to HSYNC and VSYNC, specifies the data enable + signal 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. +- sync-on-green-active: active state of Sync-on-green (SoG) signal, 0/1 for + LOW/HIGH respectively. +- 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. + If the hardware does not support lane reordering, monotonically + incremented values shall be used from 0 or 1 onwards, depending on + whether or not there is also a clock lane. 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. +- link-frequencies: Allowed data bus frequencies. For MIPI CSI-2, for + instance, this is the actual frequency of the bus, not bits per clock per + lane value. An array of 64-bit unsigned integers. +- lane-polarities: an array of polarities of the lanes starting from the clock + lane and followed by the data lanes in the same order as in data-lanes. + Valid values are 0 (normal) and 1 (inverted). The length of the array + should be the combined length of data-lanes and clock-lanes properties. + If the lane-polarities property is omitted, the value must be interpreted + as 0 (normal). This property is valid for serial busses only. +- strobe: Whether the clock signal is used as clock (0) or strobe (1). Used + with CCP2, for instance. + +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@fe910000 { + 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@fff20000 { + ... + ov772x_1: camera@21 { + compatible = "ovti,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@1a { + 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@ffc90000 { + 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>; + }; + }; + }; |