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Device tree bindings for GPMC connected NANDs
GPMC connected NAND (found on OMAP boards) are represented as child nodes of
the GPMC controller with a name of "nand".
All timing relevant properties as well as generic gpmc child properties are
explained in a separate documents - please refer to
Documentation/devicetree/bindings/bus/ti-gpmc.txt
For NAND specific properties such as ECC modes or bus width, please refer to
Documentation/devicetree/bindings/mtd/nand.txt
Required properties:
- reg: The CS line the peripheral is connected to
Optional properties:
- nand-bus-width: Set this numeric value to 16 if the hardware
is wired that way. If not specified, a bus
width of 8 is assumed.
- ti,nand-ecc-opt: A string setting the ECC layout to use. One of:
"sw" <deprecated> use "ham1" instead
"hw" <deprecated> use "ham1" instead
"hw-romcode" <deprecated> use "ham1" instead
"ham1" 1-bit Hamming ecc code
"bch4" 4-bit BCH ecc code
"bch8" 8-bit BCH ecc code
- ti,nand-xfer-type: A string setting the data transfer type. One of:
"prefetch-polled" Prefetch polled mode (default)
"polled" Polled mode, without prefetch
"prefetch-dma" Prefetch enabled sDMA mode
"prefetch-irq" Prefetch enabled irq mode
- elm_id: <deprecated> use "ti,elm-id" instead
- ti,elm-id: Specifies phandle of the ELM devicetree node.
ELM is an on-chip hardware engine on TI SoC which is used for
locating ECC errors for BCHx algorithms. SoC devices which have
ELM hardware engines should specify this device node in .dtsi
Using ELM for ECC error correction frees some CPU cycles.
For inline partition table parsing (optional):
- #address-cells: should be set to 1
- #size-cells: should be set to 1
Example for an AM33xx board:
gpmc: gpmc@50000000 {
compatible = "ti,am3352-gpmc";
ti,hwmods = "gpmc";
reg = <0x50000000 0x1000000>;
interrupts = <100>;
gpmc,num-cs = <8>;
gpmc,num-waitpins = <2>;
#address-cells = <2>;
#size-cells = <1>;
ranges = <0 0 0x08000000 0x2000>; /* CS0: NAND */
elm_id = <&elm>;
nand@0,0 {
reg = <0 0 0>; /* CS0, offset 0 */
nand-bus-width = <16>;
ti,nand-ecc-opt = "bch8";
ti,nand-xfer-type = "polled";
gpmc,sync-clk-ps = <0>;
gpmc,cs-on-ns = <0>;
gpmc,cs-rd-off-ns = <44>;
gpmc,cs-wr-off-ns = <44>;
gpmc,adv-on-ns = <6>;
gpmc,adv-rd-off-ns = <34>;
gpmc,adv-wr-off-ns = <44>;
gpmc,we-off-ns = <40>;
gpmc,oe-off-ns = <54>;
gpmc,access-ns = <64>;
gpmc,rd-cycle-ns = <82>;
gpmc,wr-cycle-ns = <82>;
gpmc,wr-access-ns = <40>;
gpmc,wr-data-mux-bus-ns = <0>;
#address-cells = <1>;
#size-cells = <1>;
/* partitions go here */
};
};
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