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

   1 * Synopsys Designware Mobile Storage Host Controller
   2
   3 The Synopsys 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 Synopsys Designware Mobile Storage Host Controller.
   7
   8 Required Properties:
   9
  10 * compatible: should be
  11         - snps,dw-mshc: for controllers compliant with synopsys 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 * resets: phandle + reset specifier pair, intended to represent hardware
  43   reset signal present internally in some host controller IC designs.
  44   See Documentation/devicetree/bindings/reset/reset.txt for details.
  45
  46 * clocks: from common clock binding: handle to biu and ciu clocks for the
  47   bus interface unit clock and the card interface unit clock.
  48
  49 * clock-names: from common clock binding: Shall be "biu" and "ciu".
  50   If the biu clock is missing we'll simply skip enabling it.  If the
  51   ciu clock is missing we'll just assume that the clock is running at
  52   clock-frequency.  It is an error to omit both the ciu clock and the
  53   clock-frequency.
  54
  55 * clock-frequency: should be the frequency (in Hz) of the ciu clock.  If this
  56   is specified and the ciu clock is specified then we'll try to set the ciu
  57   clock to this at probe time.
  58
  59 * clock-freq-min-max: Minimum and Maximum clock frequency for card output
  60   clock(cclk_out). If it's not specified, max is 200MHZ and min is 400KHz by default.
  61
  62 * num-slots: specifies the number of slots supported by the controller.
  63   The number of physical slots actually used could be equal or less than the
  64   value specified by num-slots. If this property is not specified, the value
  65   of num-slot property is assumed to be 1.
  66
  67 * fifo-depth: The maximum size of the tx/rx fifo's. If this property is not
  68   specified, the default value of the fifo size is determined from the
  69   controller registers.
  70
  71 * card-detect-delay: Delay in milli-seconds before detecting card after card
  72   insert event. The default value is 0.
  73
  74 * supports-highspeed (DEPRECATED): Enables support for high speed cards (up to 50MHz)
  75                            (use "cap-mmc-highspeed" or "cap-sd-highspeed" instead)
  76
  77 * broken-cd: as documented in mmc core bindings.
  78
  79 * vmmc-supply: The phandle to the regulator to use for vmmc.  If this is
  80   specified we'll defer probe until we can find this regulator.
  81
  82 * dmas: List of DMA specifiers with the controller specific format as described
  83   in the generic DMA client binding. Refer to dma.txt for details.
  84
  85 * dma-names: request names for generic DMA client binding. Must be "rx-tx".
  86   Refer to dma.txt for details.
  87
  88 Aliases:
  89
  90 - All the MSHC controller nodes should be represented in the aliases node using
  91   the following format 'mshc{n}' where n is a unique number for the alias.
  92
  93 Example:
  94
  95 The MSHC controller node can be split into two portions, SoC specific and
  96 board specific portions as listed below.
  97
  98         dwmmc0@12200000 {
  99                 compatible = "snps,dw-mshc";
 100                 clocks = <&clock 351>, <&clock 132>;
 101                 clock-names = "biu", "ciu";
 102                 reg = <0x12200000 0x1000>;
 103                 interrupts = <0 75 0>;
 104                 #address-cells = <1>;
 105                 #size-cells = <0>;
 106         };
 107
 108 [board specific internal DMA resources]
 109
 110         dwmmc0@12200000 {
 111                 clock-frequency = <400000000>;
 112                 clock-freq-min-max = <400000 200000000>;
 113                 num-slots = <1>;
 114                 broken-cd;
 115                 fifo-depth = <0x80>;
 116                 card-detect-delay = <200>;
 117                 vmmc-supply = <&buck8>;
 118                 bus-width = <8>;
 119                 cap-mmc-highspeed;
 120                 cap-sd-highspeed;
 121         };
 122
 123 [board specific generic DMA request binding]
 124
 125         dwmmc0@12200000 {
 126                 clock-frequency = <400000000>;
 127                 clock-freq-min-max = <400000 200000000>;
 128                 num-slots = <1>;
 129                 broken-cd;
 130                 fifo-depth = <0x80>;
 131                 card-detect-delay = <200>;
 132                 vmmc-supply = <&buck8>;
 133                 bus-width = <8>;
 134                 cap-mmc-highspeed;
 135                 cap-sd-highspeed;
 136                 dmas = <&pdma 12>;
 137                 dma-names = "rx-tx";
 138         };