diff --git a/Documentation/devicetree/bindings/bus/renesas,bsc.txt b/Documentation/devicetree/bindings/bus/renesas,bsc.txt new file mode 100644 index 000000000000..90e947269437 --- /dev/null +++ b/Documentation/devicetree/bindings/bus/renesas,bsc.txt @@ -0,0 +1,46 @@ +Renesas Bus State Controller (BSC) +================================== + +The Renesas Bus State Controller (BSC, sometimes called "LBSC within Bus +Bridge", or "External Bus Interface") can be found in several Renesas ARM SoCs. +It provides an external bus for connecting multiple external devices to the +SoC, driving several chip select lines, for e.g. NOR FLASH, Ethernet and USB. + +While the BSC is a fairly simple memory-mapped bus, it may be part of a PM +domain, and may have a gateable functional clock. +Before a device connected to the BSC can be accessed, the PM domain +containing the BSC must be powered on, and the functional clock +driving the BSC must be enabled. + +The bindings for the BSC extend the bindings for "simple-pm-bus". + + +Required properties + - compatible: Must contain an SoC-specific value, and "renesas,bsc" and + "simple-pm-bus" as fallbacks. + SoC-specific values can be: + "renesas,bsc-r8a73a4" for R-Mobile APE6 (r8a73a4) + "renesas,bsc-sh73a0" for SH-Mobile AG5 (sh73a0) + - #address-cells, #size-cells, ranges: Must describe the mapping between + parent address and child address spaces. + - reg: Must contain the base address and length to access the bus controller. + +Optional properties: + - interrupts: Must contain a reference to the BSC interrupt, if available. + - clocks: Must contain a reference to the functional clock, if available. + - power-domains: Must contain a reference to the PM domain, if available. + + +Example: + + bsc: bus@fec10000 { + compatible = "renesas,bsc-sh73a0", "renesas,bsc", + "simple-pm-bus"; + #address-cells = <1>; + #size-cells = <1>; + ranges = <0 0 0x20000000>; + reg = <0xfec10000 0x400>; + interrupts = <0 39 IRQ_TYPE_LEVEL_HIGH>; + clocks = <&zb_clk>; + power-domains = <&pd_a4s>; + };