Documentation/devicetree/bindings/mmc/synopsis-dw-mshc.txt

   1 * Synopsis Designware Mobile Storage Host Controller
   2
   3 The Synopsis designware mobile storage host controller is used to interface
   4 a SoC with storage medium such as eMMC or SD/MMC cards. This file documents
   5 differences between the core mmc properties described by mmc.txt and the
   6 properties used by the Synopsis Designware Mobile Storage Host Controller.
   7
   8 Required 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
  40 Optional properties:
  41
  42 * clocks: from common clock binding: handle to biu and ciu clocks for the
  43   bus interface unit clock and the card interface unit clock.
  44
  45 * clock-names: from common clock binding: Shall be "biu" and "ciu".
  46   If the biu clock is missing we'll simply skip enabling it.  If the
  47   ciu clock is missing we'll just assume that the clock is running at
  48   clock-frequency.  It is an error to omit both the ciu clock and the
  49   clock-frequency.
  50
  51 * clock-frequency: should be the frequency (in Hz) of the ciu clock.  If this
  52   is specified and the ciu clock is specified then we'll try to set the ciu
  53   clock to this at probe time.
  54
  55 * num-slots: specifies the number of slots supported by the controller.
  56   The number of physical slots actually used could be equal or less than the
  57   value specified by num-slots. If this property is not specified, the value
  58   of num-slot property is assumed to be 1.
  59
  60 * fifo-depth: The maximum size of the tx/rx fifo's. If this property is not
  61   specified, the default value of the fifo size is determined from the
  62   controller registers.
  63
  64 * card-detect-delay: Delay in milli-seconds before detecting card after card
  65   insert event. The default value is 0.
  66
  67 * supports-highspeed: Enables support for high speed cards (up to 50MHz)
  68
  69 * broken-cd: as documented in mmc core bindings.
  70
  71 * vmmc-supply: The phandle to the regulator to use for vmmc.  If this is
  72   specified we'll defer probe until we can find this regulator.
  73
  74 Aliases:
  75
  76 - All the MSHC controller nodes should be represented in the aliases node using
  77   the following format 'mshc{n}' where n is a unique number for the alias.
  78
  79 Example:
  80
  81 The MSHC controller node can be split into two portions, SoC specific and
  82 board specific portions as listed below.
  83
  84         dwmmc0@12200000 {
  85                 compatible = "snps,dw-mshc";
  86                 clocks = <&clock 351>, <&clock 132>;
  87                 clock-names = "biu", "ciu";
  88                 reg = <0x12200000 0x1000>;
  89                 interrupts = <0 75 0>;
  90                 #address-cells = <1>;
  91                 #size-cells = <0>;
  92         };
  93
  94         dwmmc0@12200000 {
  95                 clock-frequency = <400000000>;
  96                 num-slots = <1>;
  97                 supports-highspeed;
  98                 broken-cd;
  99                 fifo-depth = <0x80>;
 100                 card-detect-delay = <200>;
 101                 vmmc-supply = <&buck8>;
 102
 103                 slot@0 {
 104                         reg = <0>;
 105                         bus-width = <8>;
 106                 };
 107         };