98 lines
3.4 KiB
Plaintext
98 lines
3.4 KiB
Plaintext
Device tree bindings for Ethernet chip connected to TI GPMC
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Besides being used to interface with external memory devices, the
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General-Purpose Memory Controller can be used to connect Pseudo-SRAM devices
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such as ethernet controllers to processors using the TI GPMC as a data bus.
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Ethernet controllers connected to TI GPMC are represented as child nodes of
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the GPMC controller with an "ethernet" name.
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All timing relevant properties as well as generic GPMC child properties are
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explained in a separate documents. Please refer to
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Documentation/devicetree/bindings/memory-controllers/omap-gpmc.txt
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For the properties relevant to the ethernet controller connected to the GPMC
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refer to the binding documentation of the device. For example, the documentation
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for the SMSC 911x is Documentation/devicetree/bindings/net/smsc,lan9115.yaml
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Child nodes need to specify the GPMC bus address width using the "bank-width"
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property but is possible that an ethernet controller also has a property to
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specify the I/O registers address width. Even when the GPMC has a maximum 16-bit
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address width, it supports devices with 32-bit word registers.
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For example with an SMSC LAN911x/912x controller connected to the TI GPMC on an
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OMAP2+ board, "bank-width = <2>;" and "reg-io-width = <4>;".
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Required properties:
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- bank-width: Address width of the device in bytes. GPMC supports 8-bit
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and 16-bit devices and so must be either 1 or 2 bytes.
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- compatible: Compatible string property for the ethernet child device.
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- gpmc,cs-on-ns: Chip-select assertion time
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- gpmc,cs-rd-off-ns: Chip-select de-assertion time for reads
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- gpmc,cs-wr-off-ns: Chip-select de-assertion time for writes
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- gpmc,oe-on-ns: Output-enable assertion time
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- gpmc,oe-off-ns: Output-enable de-assertion time
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- gpmc,we-on-ns: Write-enable assertion time
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- gpmc,we-off-ns: Write-enable de-assertion time
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- gpmc,access-ns: Start cycle to first data capture (read access)
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- gpmc,rd-cycle-ns: Total read cycle time
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- gpmc,wr-cycle-ns: Total write cycle time
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- reg: Chip-select, base address (relative to chip-select)
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and size of the memory mapped for the device.
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Note that base address will be typically 0 as this
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is the start of the chip-select.
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Optional properties:
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- gpmc,XXX Additional GPMC timings and settings parameters. See
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Documentation/devicetree/bindings/memory-controllers/omap-gpmc.txt
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Example:
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gpmc: gpmc@6e000000 {
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compatible = "ti,omap3430-gpmc";
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ti,hwmods = "gpmc";
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reg = <0x6e000000 0x1000>;
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interrupts = <20>;
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gpmc,num-cs = <8>;
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gpmc,num-waitpins = <4>;
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#address-cells = <2>;
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#size-cells = <1>;
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ranges = <5 0 0x2c000000 0x1000000>;
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ethernet@5,0 {
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compatible = "smsc,lan9221", "smsc,lan9115";
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reg = <5 0 0xff>;
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bank-width = <2>;
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gpmc,mux-add-data;
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gpmc,cs-on-ns = <0>;
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gpmc,cs-rd-off-ns = <186>;
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gpmc,cs-wr-off-ns = <186>;
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gpmc,adv-on-ns = <12>;
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gpmc,adv-rd-off-ns = <48>;
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gpmc,adv-wr-off-ns = <48>;
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gpmc,oe-on-ns = <54>;
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gpmc,oe-off-ns = <168>;
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gpmc,we-on-ns = <54>;
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gpmc,we-off-ns = <168>;
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gpmc,rd-cycle-ns = <186>;
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gpmc,wr-cycle-ns = <186>;
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gpmc,access-ns = <114>;
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gpmc,page-burst-access-ns = <6>;
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gpmc,bus-turnaround-ns = <12>;
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gpmc,cycle2cycle-delay-ns = <18>;
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gpmc,wr-data-mux-bus-ns = <90>;
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gpmc,wr-access-ns = <186>;
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gpmc,cycle2cycle-samecsen;
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gpmc,cycle2cycle-diffcsen;
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interrupt-parent = <&gpio6>;
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interrupts = <16>;
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vmmc-supply = <&vddvario>;
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vmmc_aux-supply = <&vdd33a>;
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reg-io-width = <4>;
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smsc,save-mac-address;
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};
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};
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