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Diffstat (limited to 'Documentation/devicetree/bindings/mfd/aspeed-lpc.txt')
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diff --git a/Documentation/devicetree/bindings/mfd/aspeed-lpc.txt b/Documentation/devicetree/bindings/mfd/aspeed-lpc.txt deleted file mode 100644 index 86446074e206..000000000000 --- a/Documentation/devicetree/bindings/mfd/aspeed-lpc.txt +++ /dev/null @@ -1,201 +0,0 @@ -====================================================================== -Device tree bindings for the Aspeed Low Pin Count (LPC) Bus Controller -====================================================================== - -The LPC bus is a means to bridge a host CPU to a number of low-bandwidth -peripheral devices, replacing the use of the ISA bus in the age of PCI[0]. The -primary use case of the Aspeed LPC controller is as a slave on the bus -(typically in a Baseboard Management Controller SoC), but under certain -conditions it can also take the role of bus master. - -The LPC controller is represented as a multi-function device to account for the -mix of functionality it provides. The principle split is between the register -layout at the start of the I/O space which is, to quote the Aspeed datasheet, -"basically compatible with the [LPC registers from the] popular BMC controller -H8S/2168[1]", and everything else, where everything else is an eclectic -collection of functions with a esoteric register layout. "Everything else", -here labeled the "host" portion of the controller, includes, but is not limited -to: - -* An IPMI Block Transfer[2] Controller - -* An LPC Host Controller: Manages LPC functions such as host vs slave mode, the - physical properties of some LPC pins, configuration of serial IRQs, and - APB-to-LPC bridging amonst other functions. - -* An LPC Host Interface Controller: Manages functions exposed to the host such - as LPC firmware hub cycles, configuration of the LPC-to-AHB mapping, UART - management and bus snoop configuration. - -* A set of SuperIO[3] scratch registers: Enables implementation of e.g. custom - hardware management protocols for handover between the host and baseboard - management controller. - -Additionally the state of the LPC controller influences the pinmux -configuration, therefore the host portion of the controller is exposed as a -syscon as a means to arbitrate access. - -[0] http://www.intel.com/design/chipsets/industry/25128901.pdf -[1] https://www.renesas.com/en-sg/doc/products/mpumcu/001/rej09b0078_h8s2168.pdf?key=7c88837454702128622bee53acbda8f4 -[2] http://www.intel.com/content/dam/www/public/us/en/documents/product-briefs/ipmi-second-gen-interface-spec-v2-rev1-1.pdf -[3] https://en.wikipedia.org/wiki/Super_I/O - -Required properties -=================== - -- compatible: One of: - "aspeed,ast2400-lpc", "simple-mfd" - "aspeed,ast2500-lpc", "simple-mfd" - -- reg: contains the physical address and length values of the Aspeed - LPC memory region. - -- #address-cells: <1> -- #size-cells: <1> -- ranges: Maps 0 to the physical address and length of the LPC memory - region - -Required LPC Child nodes -======================== - -BMC Node --------- - -- compatible: One of: - "aspeed,ast2400-lpc-bmc" - "aspeed,ast2500-lpc-bmc" - -- reg: contains the physical address and length values of the - H8S/2168-compatible LPC controller memory region - -Host Node ---------- - -- compatible: One of: - "aspeed,ast2400-lpc-host", "simple-mfd", "syscon" - "aspeed,ast2500-lpc-host", "simple-mfd", "syscon" - -- reg: contains the address and length values of the host-related - register space for the Aspeed LPC controller - -- #address-cells: <1> -- #size-cells: <1> -- ranges: Maps 0 to the address and length of the host-related LPC memory - region - -Example: - -lpc: lpc@1e789000 { - compatible = "aspeed,ast2500-lpc", "simple-mfd"; - reg = <0x1e789000 0x1000>; - - #address-cells = <1>; - #size-cells = <1>; - ranges = <0x0 0x1e789000 0x1000>; - - lpc_bmc: lpc-bmc@0 { - compatible = "aspeed,ast2500-lpc-bmc"; - reg = <0x0 0x80>; - }; - - lpc_host: lpc-host@80 { - compatible = "aspeed,ast2500-lpc-host", "simple-mfd", "syscon"; - reg = <0x80 0x1e0>; - reg-io-width = <4>; - - #address-cells = <1>; - #size-cells = <1>; - ranges = <0x0 0x80 0x1e0>; - }; -}; - -BMC Node Children -================== - - -Host Node Children -================== - -LPC Host Interface Controller -------------------- - -The LPC Host Interface Controller manages functions exposed to the host such as -LPC firmware hub cycles, configuration of the LPC-to-AHB mapping, UART -management and bus snoop configuration. - -Required properties: - -- compatible: One of: - "aspeed,ast2400-lpc-ctrl"; - "aspeed,ast2500-lpc-ctrl"; - -- reg: contains offset/length values of the host interface controller - memory regions - -- clocks: contains a phandle to the syscon node describing the clocks. - There should then be one cell representing the clock to use - -Optional properties: - -- memory-region: A phandle to a reserved_memory region to be used for the LPC - to AHB mapping - -- flash: A phandle to the SPI flash controller containing the flash to - be exposed over the LPC to AHB mapping - -Example: - -lpc-host@80 { - lpc_ctrl: lpc-ctrl@0 { - compatible = "aspeed,ast2500-lpc-ctrl"; - reg = <0x0 0x80>; - clocks = <&syscon ASPEED_CLK_GATE_LCLK>; - memory-region = <&flash_memory>; - flash = <&spi>; - }; -}; - -LPC Host Controller -------------------- - -The Aspeed LPC Host Controller configures the Low Pin Count (LPC) bus behaviour -between the host and the baseboard management controller. The registers exist -in the "host" portion of the Aspeed LPC controller, which must be the parent of -the LPC host controller node. - -Required properties: - -- compatible: One of: - "aspeed,ast2400-lhc"; - "aspeed,ast2500-lhc"; - -- reg: contains offset/length values of the LHC memory regions. In the - AST2400 and AST2500 there are two regions. - -Example: - -lhc: lhc@20 { - compatible = "aspeed,ast2500-lhc"; - reg = <0x20 0x24 0x48 0x8>; -}; - -LPC reset control ------------------ - -The UARTs present in the ASPEED SoC can have their resets tied to the reset -state of the LPC bus. Some systems may chose to modify this configuration. - -Required properties: - - - compatible: "aspeed,ast2500-lpc-reset" or - "aspeed,ast2400-lpc-reset" - - reg: offset and length of the IP in the LHC memory region - - #reset-controller indicates the number of reset cells expected - -Example: - -lpc_reset: reset-controller@18 { - compatible = "aspeed,ast2500-lpc-reset"; - reg = <0x18 0x4>; - #reset-cells = <1>; -}; |