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47 lines
1.7 KiB
47 lines
1.7 KiB
GPIO assisted NAND flash
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The GPIO assisted NAND flash uses a memory mapped interface to
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read/write the NAND commands and data and GPIO pins for the control
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signals.
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Required properties:
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- compatible : "gpio-control-nand"
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- reg : should specify localbus chip select and size used for the chip. The
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resource describes the data bus connected to the NAND flash and all accesses
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are made in native endianness.
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- #address-cells, #size-cells : Must be present if the device has sub-nodes
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representing partitions.
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- gpios : Specifies the GPIO pins to control the NAND device. The order of
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GPIO references is: RDY, nCE, ALE, CLE, and nWP. nCE and nWP are optional.
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Optional properties:
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- bank-width : Width (in bytes) of the device. If not present, the width
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defaults to 1 byte.
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- chip-delay : chip dependent delay for transferring data from array to
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read registers (tR). If not present then a default of 20us is used.
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- gpio-control-nand,io-sync-reg : A 64-bit physical address for a read
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location used to guard against bus reordering with regards to accesses to
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the GPIO's and the NAND flash data bus. If present, then after changing
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GPIO state and before and after command byte writes, this register will be
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read to ensure that the GPIO accesses have completed.
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The device tree may optionally contain sub-nodes describing partitions of the
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address space. See partition.txt for more detail.
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Examples:
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gpio-nand@1,0 {
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compatible = "gpio-control-nand";
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reg = <1 0x0000 0x2>;
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#address-cells = <1>;
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#size-cells = <1>;
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gpios = <&banka 1 0>, /* RDY */
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<0>, /* nCE */
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<&banka 3 0>, /* ALE */
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<&banka 4 0>, /* CLE */
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<0>; /* nWP */
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partition@0 {
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...
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};
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};
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