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Diffstat (limited to 'Bindings/media/renesas,drif.txt')
| -rw-r--r-- | Bindings/media/renesas,drif.txt | 176 |
1 files changed, 176 insertions, 0 deletions
diff --git a/Bindings/media/renesas,drif.txt b/Bindings/media/renesas,drif.txt new file mode 100644 index 000000000000..39516b94c28f --- /dev/null +++ b/Bindings/media/renesas,drif.txt @@ -0,0 +1,176 @@ +Renesas R-Car Gen3 Digital Radio Interface controller (DRIF) +------------------------------------------------------------ + +R-Car Gen3 DRIF is a SPI like receive only slave device. A general +representation of DRIF interfacing with a master device is shown below. + ++---------------------+ +---------------------+ +| |-----SCK------->|CLK | +| Master |-----SS-------->|SYNC DRIFn (slave) | +| |-----SD0------->|D0 | +| |-----SD1------->|D1 | ++---------------------+ +---------------------+ + +As per datasheet, each DRIF channel (drifn) is made up of two internal +channels (drifn0 & drifn1). These two internal channels share the common +CLK & SYNC. Each internal channel has its own dedicated resources like +irq, dma channels, address space & clock. This internal split is not +visible to the external master device. + +The device tree model represents each internal channel as a separate node. +The internal channels sharing the CLK & SYNC are tied together by their +phandles using a property called "renesas,bonding". For the rest of +the documentation, unless explicitly stated, the word channel implies an +internal channel. + +When both internal channels are enabled they need to be managed together +as one (i.e.) they cannot operate alone as independent devices. Out of the +two, one of them needs to act as a primary device that accepts common +properties of both the internal channels. This channel is identified by a +property called "renesas,primary-bond". + +To summarize, + - When both the internal channels that are bonded together are enabled, + the zeroth channel is selected as primary-bond. This channels accepts + properties common to all the members of the bond. + - When only one of the bonded channels need to be enabled, the property + "renesas,bonding" or "renesas,primary-bond" will have no effect. That + enabled channel can act alone as any other independent device. + +Required properties of an internal channel: +------------------------------------------- +- compatible: "renesas,r8a7795-drif" if DRIF controller is a part of R8A7795 SoC. + "renesas,rcar-gen3-drif" for a generic R-Car Gen3 compatible device. + + When compatible with the generic version, nodes must list the + SoC-specific version corresponding to the platform first + followed by the generic version. + +- reg: offset and length of that channel. +- interrupts: associated with that channel. +- clocks: phandle and clock specifier of that channel. +- clock-names: clock input name string: "fck". +- dmas: phandles to the DMA channels. +- dma-names: names of the DMA channel: "rx". +- renesas,bonding: phandle to the other channel. + +Optional properties of an internal channel: +------------------------------------------- +- power-domains: phandle to the respective power domain. + +Required properties of an internal channel when: + - It is the only enabled channel of the bond (or) + - If it acts as primary among enabled bonds +-------------------------------------------------------- +- pinctrl-0: pin control group to be used for this channel. +- pinctrl-names: must be "default". +- renesas,primary-bond: empty property indicating the channel acts as primary + among the bonded channels. +- port: child port node corresponding to the data input, in accordance with + the video interface bindings defined in + Documentation/devicetree/bindings/media/video-interfaces.txt. The port + node must contain at least one endpoint. + +Optional endpoint property: +--------------------------- +- sync-active: Indicates sync signal polarity, 0/1 for low/high respectively. + This property maps to SYNCAC bit in the hardware manual. The + default is 1 (active high). + +Example: +-------- + +(1) Both internal channels enabled: +----------------------------------- + +When interfacing with a third party tuner device with two data pins as shown +below. + ++---------------------+ +---------------------+ +| |-----SCK------->|CLK | +| Master |-----SS-------->|SYNC DRIFn (slave) | +| |-----SD0------->|D0 | +| |-----SD1------->|D1 | ++---------------------+ +---------------------+ + + drif00: rif@e6f40000 { + compatible = "renesas,r8a7795-drif", + "renesas,rcar-gen3-drif"; + reg = <0 0xe6f40000 0 0x64>; + interrupts = <GIC_SPI 12 IRQ_TYPE_LEVEL_HIGH>; + clocks = <&cpg CPG_MOD 515>; + clock-names = "fck"; + dmas = <&dmac1 0x20>, <&dmac2 0x20>; + dma-names = "rx", "rx"; + power-domains = <&sysc R8A7795_PD_ALWAYS_ON>; + renesas,bonding = <&drif01>; + renesas,primary-bond; + pinctrl-0 = <&drif0_pins>; + pinctrl-names = "default"; + port { + drif0_ep: endpoint { + remote-endpoint = <&tuner_ep>; + }; + }; + }; + + drif01: rif@e6f50000 { + compatible = "renesas,r8a7795-drif", + "renesas,rcar-gen3-drif"; + reg = <0 0xe6f50000 0 0x64>; + interrupts = <GIC_SPI 13 IRQ_TYPE_LEVEL_HIGH>; + clocks = <&cpg CPG_MOD 514>; + clock-names = "fck"; + dmas = <&dmac1 0x22>, <&dmac2 0x22>; + dma-names = "rx", "rx"; + power-domains = <&sysc R8A7795_PD_ALWAYS_ON>; + renesas,bonding = <&drif00>; + }; + + +(2) Internal channel 1 alone is enabled: +---------------------------------------- + +When interfacing with a third party tuner device with one data pin as shown +below. + ++---------------------+ +---------------------+ +| |-----SCK------->|CLK | +| Master |-----SS-------->|SYNC DRIFn (slave) | +| | |D0 (unused) | +| |-----SD-------->|D1 | ++---------------------+ +---------------------+ + + drif00: rif@e6f40000 { + compatible = "renesas,r8a7795-drif", + "renesas,rcar-gen3-drif"; + reg = <0 0xe6f40000 0 0x64>; + interrupts = <GIC_SPI 12 IRQ_TYPE_LEVEL_HIGH>; + clocks = <&cpg CPG_MOD 515>; + clock-names = "fck"; + dmas = <&dmac1 0x20>, <&dmac2 0x20>; + dma-names = "rx", "rx"; + power-domains = <&sysc R8A7795_PD_ALWAYS_ON>; + renesas,bonding = <&drif01>; + }; + + drif01: rif@e6f50000 { + compatible = "renesas,r8a7795-drif", + "renesas,rcar-gen3-drif"; + reg = <0 0xe6f50000 0 0x64>; + interrupts = <GIC_SPI 13 IRQ_TYPE_LEVEL_HIGH>; + clocks = <&cpg CPG_MOD 514>; + clock-names = "fck"; + dmas = <&dmac1 0x22>, <&dmac2 0x22>; + dma-names = "rx", "rx"; + power-domains = <&sysc R8A7795_PD_ALWAYS_ON>; + renesas,bonding = <&drif00>; + pinctrl-0 = <&drif0_pins>; + pinctrl-names = "default"; + port { + drif0_ep: endpoint { + remote-endpoint = <&tuner_ep>; + sync-active = <0>; + }; + }; + }; |