On 12/15/2012 03:13 PM, Sylwester Nawrocki wrote: > From: Guennadi Liakhovetski <g.liakhovetski@xxxxxx> > > This patch adds a document describing common OF bindings for video > capture, output and video processing devices. It is currently mainly > focused on video capture devices, with data interfaces defined in > standards like ITU-R BT.656 or MIPI CSI-2. > It also documents a method of describing data links between devices. > > Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@xxxxxx> > Signed-off-by: Sylwester Nawrocki <s.nawrocki@xxxxxxxxxxx> Looks reasonable. You can merge this with the rest of the series. Acked-by: Rob Herring <rob.herring@xxxxxxxxxxx> > --- > Hi, > > This is an updated version of patch [1]. My changes include resolving > issues pointed out during review, i.e.: > - renaming 'link' node to 'endpoint, > - renaming 'remote' phandle to 'remote-endpoint', > - file v4l2.txt renamed to video-interfaces.txt, > - removed references to V4L2, > - added short description of the example DT snippet > > and additionally: > - added "Required properties' paragraph, > - updated description of 'data-lanes' property, > - renamed all erroneous occurrences of 'data-width' to 'bus-width', > - added 'bus-width' property description, > - modified description of hsync-active, vsync-active properties, > - added a little paragraph further explaining that each endpoint > node has properties determining configuration of its corresponding > device. > > [1] https://patchwork.kernel.org/patch/1514381/ > > I'm still unsure about the first sentence, as these bindings can be > used for describing SoC internal connections between modules as well. > > I was considering adding something like: > > "This document describes common bindings for video capture, processing > and output devices using data buses defined in standards like ITU-R > BT.656, MIPI CSI-2,..." > > before the "General concept" paragraph. > > And maybe Documentation/devicetree/bindings/video/ would a better place > for this video-interfaces.txt file ? > > Thanks, > Sylwester > --- > .../devicetree/bindings/media/video-interfaces.txt | 198 ++++++++++++++++++++ > 1 files changed, 198 insertions(+), 0 deletions(-) > create mode 100644 Documentation/devicetree/bindings/media/video-interfaces.txt > > diff --git a/Documentation/devicetree/bindings/media/video-interfaces.txt b/Documentation/devicetree/bindings/media/video-interfaces.txt > new file mode 100644 > index 0000000..10ebbc4 > --- /dev/null > +++ b/Documentation/devicetree/bindings/media/video-interfaces.txt > @@ -0,0 +1,198 @@ > +Common bindings for video data 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. > + > +dev { > + #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 other 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, a common scheme, using '#address-cells', '#size-cells' and 'reg' properties > +is used. > + > +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 the other device. In most > +cases properties at the peer 'endpoint' nodes will be identical, however > +they might need to be different when there are any signal modifications on the > +bus between two devices, e.g. there are logic signal inverters on the lines. > + > +Required properties > +------------------- > + > +If there is more that one 'port' or more than one 'endpoint' node following > +properties are required in relevant parent node: > + > +- #address-cells : number of cells required to define port number, should be 1. > +- #size-cells : should be zero. > + > +Optional endpoint properties > +---------------------------- > + > +- remote-endpoint : phandle to an 'endpoint' subnode of the other device node. > +- slave-mode : a boolean property, run the link in slave mode. Default is master > + mode. > +- bus-width : the number of data lines, valid for parallel buses. > +- data-shift: on 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=<10>; data-shift=<2>;" means, that lines 9:2 are used. > +- hsync-active : active state of HSYNC signal, 0/1 for LOW/HIGH respectively. > +- vsync-active : active state of 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 : rising (1) or falling (0) edge to sample the pixel clock signal. > +- data-lanes : an array of physical data lane indexes. Position of an entry > + determines 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 buses only (e.g. MIPI CSI-2). > +- clock-lanes : a number of physical lane used as a clock lane. > +- clock-noncontinuous : a boolean property to allow MIPI CSI-2 non-continuous > + clock mode. > + > +Example > +------- > + > +The below example snippet describes two data pipelines. ov772x and imx074 are > +camera sensors with parallel and serial (MIPI CSI-2) video bus respectively. > +Both sensors are on I2C control bus corresponding to i2c0 controller node. > +ov772x sensor is linked directly to the ceu0 video host interface. imx074 is > +linked to ceu0 through MIPI CSI-2 receiver (csi2). ceu0 has a (single) DMA > +engine writing captured data to memory. ceu0 node has single 'port' node which > +indicates at any time only one of following data pipeline 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>; > + > + ceu0_1: endpoint@1 { > + reg = <1>; /* Local endpoint # */ > + remote = <&ov772x_1_1>; /* Remote phandle */ > + bus-width = <8>; /* Used data lines */ > + data-shift = <0>; /* Lines 7:0 are used */ > + > + /* If hsync-active/vsync-active are missing, > + embedded bt.605 sync is used */ > + hsync-active = <1>; /* Active high */ > + vsync-active = <1>; /* Active high */ > + data-active = <1>; /* Active high */ > + pclk-sample = <1>; /* Rising */ > + }; > + > + ceu0_0: endpoint@0 { > + reg = <0>; > + remote = <&csi2_2>; > + immutable; > + }; > + }; > + }; > + > + 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 in 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 { > + immutable; > + remote-endpoint = <&ceu0_0>; > + }; > + }; > + }; > -- > 1.7.4.1 > > _______________________________________________ > devicetree-discuss mailing list > devicetree-discuss@xxxxxxxxxxxxxxxx > https://lists.ozlabs.org/listinfo/devicetree-discuss > -- To unsubscribe from this list: send the line "unsubscribe linux-doc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
