Documentation/devicetree/bindings/net/gpmc-eth.txt

   1 Device tree bindings for Ethernet chip connected to TI GPMC
   2
   3 Besides being used to interface with external memory devices, the
   4 General-Purpose Memory Controller can be used to connect Pseudo-SRAM devices
   5 such as ethernet controllers to processors using the TI GPMC as a data bus.
   6
   7 Ethernet controllers connected to TI GPMC are represented as child nodes of
   8 the GPMC controller with an "ethernet" name.
   9
  10 All timing relevant properties as well as generic GPMC child properties are
  11 explained in a separate documents. Please refer to
  12 Documentation/devicetree/bindings/memory-controllers/omap-gpmc.txt
  13
  14 For the properties relevant to the ethernet controller connected to the GPMC
  15 refer to the binding documentation of the device. For example, the documentation
  16 for the SMSC 911x is Documentation/devicetree/bindings/net/smsc,lan9115.yaml
  17
  18 Child nodes need to specify the GPMC bus address width using the "bank-width"
  19 property but is possible that an ethernet controller also has a property to
  20 specify the I/O registers address width. Even when the GPMC has a maximum 16-bit
  21 address width, it supports devices with 32-bit word registers.
  22 For example with an SMSC LAN911x/912x controller connected to the TI GPMC on an
  23 OMAP2+ board, "bank-width = <2>;" and "reg-io-width = <4>;".
  24
  25 Required properties:
  26 - bank-width:           Address width of the device in bytes. GPMC supports 8-bit
  27                         and 16-bit devices and so must be either 1 or 2 bytes.
  28 - compatible:           Compatible string property for the ethernet child device.
  29 - gpmc,cs-on-ns:        Chip-select assertion time
  30 - gpmc,cs-rd-off-ns:    Chip-select de-assertion time for reads
  31 - gpmc,cs-wr-off-ns:    Chip-select de-assertion time for writes
  32 - gpmc,oe-on-ns:        Output-enable assertion time
  33 - gpmc,oe-off-ns:       Output-enable de-assertion time
  34 - gpmc,we-on-ns:        Write-enable assertion time
  35 - gpmc,we-off-ns:       Write-enable de-assertion time
  36 - gpmc,access-ns:       Start cycle to first data capture (read access)
  37 - gpmc,rd-cycle-ns:     Total read cycle time
  38 - gpmc,wr-cycle-ns:     Total write cycle time
  39 - reg:                  Chip-select, base address (relative to chip-select)
  40                         and size of the memory mapped for the device.
  41                         Note that base address will be typically 0 as this
  42                         is the start of the chip-select.
  43
  44 Optional properties:
  45 - gpmc,XXX              Additional GPMC timings and settings parameters. See
  46                         Documentation/devicetree/bindings/memory-controllers/omap-gpmc.txt
  47
  48 Example:
  49
  50 gpmc: gpmc@6e000000 {
  51         compatible = "ti,omap3430-gpmc";
  52         ti,hwmods = "gpmc";
  53         reg = <0x6e000000 0x1000>;
  54         interrupts = <20>;
  55         gpmc,num-cs = <8>;
  56         gpmc,num-waitpins = <4>;
  57         #address-cells = <2>;
  58         #size-cells = <1>;
  59
  60         ranges = <5 0 0x2c000000 0x1000000>;
  61
  62         ethernet@5,0 {
  63                 compatible = "smsc,lan9221", "smsc,lan9115";
  64                 reg = <5 0 0xff>;
  65                 bank-width = <2>;
  66
  67                 gpmc,mux-add-data;
  68                 gpmc,cs-on-ns = <0>;
  69                 gpmc,cs-rd-off-ns = <186>;
  70                 gpmc,cs-wr-off-ns = <186>;
  71                 gpmc,adv-on-ns = <12>;
  72                 gpmc,adv-rd-off-ns = <48>;
  73                 gpmc,adv-wr-off-ns = <48>;
  74                 gpmc,oe-on-ns = <54>;
  75                 gpmc,oe-off-ns = <168>;
  76                 gpmc,we-on-ns = <54>;
  77                 gpmc,we-off-ns = <168>;
  78                 gpmc,rd-cycle-ns = <186>;
  79                 gpmc,wr-cycle-ns = <186>;
  80                 gpmc,access-ns = <114>;
  81                 gpmc,page-burst-access-ns = <6>;
  82                 gpmc,bus-turnaround-ns = <12>;
  83                 gpmc,cycle2cycle-delay-ns = <18>;
  84                 gpmc,wr-data-mux-bus-ns = <90>;
  85                 gpmc,wr-access-ns = <186>;
  86                 gpmc,cycle2cycle-samecsen;
  87                 gpmc,cycle2cycle-diffcsen;
  88
  89                 interrupt-parent = <&gpio6>;
  90                 interrupts = <16>;
  91                 vmmc-supply = <&vddvario>;
  92                 vmmc_aux-supply = <&vdd33a>;
  93                 reg-io-width = <4>;
  94
  95                 smsc,save-mac-address;
  96         };
  97 };