| Igor Sarkisov | 914f235 | 2020-10-06 05:39:43 -0700 | [diff] [blame^] | 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/bus/ti-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/smsc911x.txt |
| 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/bus/ti-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 | }; |
