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Diffstat (limited to 'Documentation/devicetree/bindings/mmc/synopsys-dw-mshc.txt')
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diff --git a/Documentation/devicetree/bindings/mmc/synopsys-dw-mshc.txt b/Documentation/devicetree/bindings/mmc/synopsys-dw-mshc.txt new file mode 100644 index 00000000000..066a78b034c --- /dev/null +++ b/Documentation/devicetree/bindings/mmc/synopsys-dw-mshc.txt @@ -0,0 +1,107 @@ +* Synopsys Designware Mobile Storage Host Controller + +The Synopsys designware mobile storage host controller is used to interface +a SoC with storage medium such as eMMC or SD/MMC cards. This file documents +differences between the core mmc properties described by mmc.txt and the +properties used by the Synopsys Designware Mobile Storage Host Controller. + +Required Properties: + +* compatible: should be + - snps,dw-mshc: for controllers compliant with synopsys dw-mshc. +* #address-cells: should be 1. +* #size-cells: should be 0. + +# Slots: The slot specific information are contained within child-nodes with + each child-node representing a supported slot. There should be atleast one + child node representing a card slot. The name of the child node representing + the slot is recommended to be slot@n where n is the unique number of the slot + connnected to the controller. The following are optional properties which + can be included in the slot child node. + + * reg: specifies the physical slot number. The valid values of this + property is 0 to (num-slots -1), where num-slots is the value + specified by the num-slots property. + + * bus-width: as documented in mmc core bindings. + + * wp-gpios: specifies the write protect gpio line. The format of the + gpio specifier depends on the gpio controller. If a GPIO is not used + for write-protect, this property is optional. + + * disable-wp: If the wp-gpios property isn't present then (by default) + we'd assume that the write protect is hooked up directly to the + controller's special purpose write protect line (accessible via + the WRTPRT register). However, it's possible that we simply don't + want write protect. In that case specify 'disable-wp'. + NOTE: This property is not required for slots known to always + connect to eMMC or SDIO cards. + +Optional properties: + +* clocks: from common clock binding: handle to biu and ciu clocks for the + bus interface unit clock and the card interface unit clock. + +* clock-names: from common clock binding: Shall be "biu" and "ciu". + If the biu clock is missing we'll simply skip enabling it. If the + ciu clock is missing we'll just assume that the clock is running at + clock-frequency. It is an error to omit both the ciu clock and the + clock-frequency. + +* clock-frequency: should be the frequency (in Hz) of the ciu clock. If this + is specified and the ciu clock is specified then we'll try to set the ciu + clock to this at probe time. + +* num-slots: specifies the number of slots supported by the controller. + The number of physical slots actually used could be equal or less than the + value specified by num-slots. If this property is not specified, the value + of num-slot property is assumed to be 1. + +* fifo-depth: The maximum size of the tx/rx fifo's. If this property is not + specified, the default value of the fifo size is determined from the + controller registers. + +* card-detect-delay: Delay in milli-seconds before detecting card after card + insert event. The default value is 0. + +* supports-highspeed: Enables support for high speed cards (up to 50MHz) + +* broken-cd: as documented in mmc core bindings. + +* vmmc-supply: The phandle to the regulator to use for vmmc. If this is + specified we'll defer probe until we can find this regulator. + +Aliases: + +- All the MSHC controller nodes should be represented in the aliases node using + the following format 'mshc{n}' where n is a unique number for the alias. + +Example: + +The MSHC controller node can be split into two portions, SoC specific and +board specific portions as listed below. + + dwmmc0@12200000 { + compatible = "snps,dw-mshc"; + clocks = <&clock 351>, <&clock 132>; + clock-names = "biu", "ciu"; + reg = <0x12200000 0x1000>; + interrupts = <0 75 0>; + #address-cells = <1>; + #size-cells = <0>; + }; + + dwmmc0@12200000 { + clock-frequency = <400000000>; + num-slots = <1>; + supports-highspeed; + broken-cd; + fifo-depth = <0x80>; + card-detect-delay = <200>; + vmmc-supply = <&buck8>; + + slot@0 { + reg = <0>; + bus-width = <8>; + }; + }; |