linux/Documentation/devicetree/bindings/mmc/synopsis-dw-mshc.txt
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   1* Synopsis Designware Mobile Storage Host Controller
   2
   3The Synopsis designware mobile storage host controller is used to interface
   4a SoC with storage medium such as eMMC or SD/MMC cards. This file documents
   5differences between the core mmc properties described by mmc.txt and the
   6properties used by the Synopsis Designware Mobile Storage Host Controller.
   7
   8Required Properties:
   9
  10* compatible: should be
  11        - snps,dw-mshc: for controllers compliant with synopsis dw-mshc.
  12* #address-cells: should be 1.
  13* #size-cells: should be 0.
  14
  15# Slots: The slot specific information are contained within child-nodes with
  16  each child-node representing a supported slot. There should be atleast one
  17  child node representing a card slot. The name of the child node representing
  18  the slot is recommended to be slot@n where n is the unique number of the slot
  19  connnected to the controller. The following are optional properties which
  20  can be included in the slot child node.
  21
  22        * reg: specifies the physical slot number. The valid values of this
  23          property is 0 to (num-slots -1), where num-slots is the value
  24          specified by the num-slots property.
  25
  26        * bus-width: as documented in mmc core bindings.
  27
  28        * wp-gpios: specifies the write protect gpio line. The format of the
  29          gpio specifier depends on the gpio controller. If a GPIO is not used
  30          for write-protect, this property is optional.
  31
  32        * disable-wp: If the wp-gpios property isn't present then (by default)
  33          we'd assume that the write protect is hooked up directly to the
  34          controller's special purpose write protect line (accessible via
  35          the WRTPRT register).  However, it's possible that we simply don't
  36          want write protect.  In that case specify 'disable-wp'.
  37          NOTE: This property is not required for slots known to always
  38          connect to eMMC or SDIO cards.
  39
  40Optional properties:
  41
  42* num-slots: specifies the number of slots supported by the controller.
  43  The number of physical slots actually used could be equal or less than the
  44  value specified by num-slots. If this property is not specified, the value
  45  of num-slot property is assumed to be 1.
  46
  47* fifo-depth: The maximum size of the tx/rx fifo's. If this property is not
  48  specified, the default value of the fifo size is determined from the
  49  controller registers.
  50
  51* card-detect-delay: Delay in milli-seconds before detecting card after card
  52  insert event. The default value is 0.
  53
  54* supports-highspeed: Enables support for high speed cards (upto 50MHz)
  55
  56* broken-cd: as documented in mmc core bindings.
  57
  58Aliases:
  59
  60- All the MSHC controller nodes should be represented in the aliases node using
  61  the following format 'mshc{n}' where n is a unique number for the alias.
  62
  63Example:
  64
  65The MSHC controller node can be split into two portions, SoC specific and
  66board specific portions as listed below.
  67
  68        dwmmc0@12200000 {
  69                compatible = "snps,dw-mshc";
  70                reg = <0x12200000 0x1000>;
  71                interrupts = <0 75 0>;
  72                #address-cells = <1>;
  73                #size-cells = <0>;
  74        };
  75
  76        dwmmc0@12200000 {
  77                num-slots = <1>;
  78                supports-highspeed;
  79                broken-cd;
  80                fifo-depth = <0x80>;
  81                card-detect-delay = <200>;
  82
  83                slot@0 {
  84                        reg = <0>;
  85                        bus-width = <8>;
  86                };
  87        };
  88