Device tree bindings for OMAP general purpose memory controllers (GPMC)
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The actual devices are instantiated from the child nodes of a GPMC node.
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Required properties:
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- compatible: Should be set to one of the following:
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ti,omap2420-gpmc (omap2420)
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ti,omap2430-gpmc (omap2430)
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ti,omap3430-gpmc (omap3430 & omap3630)
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ti,omap4430-gpmc (omap4430 & omap4460 & omap543x)
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ti,am3352-gpmc (am335x devices)
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- reg: A resource specifier for the register space
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(see the example below)
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- ti,hwmods: Should be set to "ti,gpmc" until the DT transition is
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completed.
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- #address-cells: Must be set to 2 to allow memory address translation
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- #size-cells: Must be set to 1 to allow CS address passing
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- gpmc,num-cs: The maximum number of chip-select lines that controller
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can support.
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- gpmc,num-waitpins: The maximum number of wait pins that controller can
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support.
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- ranges: Must be set up to reflect the memory layout with four
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integer values for each chip-select line in use:
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<cs-number> 0 <physical address of mapping> <size>
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Currently, calculated values derived from the contents
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of the per-CS register GPMC_CONFIG7 (as set up by the
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bootloader) are used for the physical address decoding.
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As this will change in the future, filling correct
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values here is a requirement.
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- interrupt-controller: The GPMC driver implements and interrupt controller for
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the NAND events "fifoevent" and "termcount" plus the
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rising/falling edges on the GPMC_WAIT pins.
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The interrupt number mapping is as follows
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0 - NAND_fifoevent
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1 - NAND_termcount
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2 - GPMC_WAIT0 pin edge
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3 - GPMC_WAIT1 pin edge, and so on.
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- interrupt-cells: Must be set to 2
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- gpio-controller: The GPMC driver implements a GPIO controller for the
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GPMC WAIT pins that can be used as general purpose inputs.
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0 maps to GPMC_WAIT0 pin.
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- gpio-cells: Must be set to 2
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Required properties when using NAND prefetch dma:
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- dmas GPMC NAND prefetch dma channel
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- dma-names Must be set to "rxtx"
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Timing properties for child nodes. All are optional and default to 0.
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- gpmc,sync-clk-ps: Minimum clock period for synchronous mode, in picoseconds
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Chip-select signal timings (in nanoseconds) corresponding to GPMC_CONFIG2:
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- gpmc,cs-on-ns: Assertion time
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- gpmc,cs-rd-off-ns: Read deassertion time
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- gpmc,cs-wr-off-ns: Write deassertion time
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ADV signal timings (in nanoseconds) corresponding to GPMC_CONFIG3:
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- gpmc,adv-on-ns: Assertion time
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- gpmc,adv-rd-off-ns: Read deassertion time
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- gpmc,adv-wr-off-ns: Write deassertion time
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- gpmc,adv-aad-mux-on-ns: Assertion time for AAD
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- gpmc,adv-aad-mux-rd-off-ns: Read deassertion time for AAD
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- gpmc,adv-aad-mux-wr-off-ns: Write deassertion time for AAD
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WE signals timings (in nanoseconds) corresponding to GPMC_CONFIG4:
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- gpmc,we-on-ns Assertion time
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- gpmc,we-off-ns: Deassertion time
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OE signals timings (in nanoseconds) corresponding to GPMC_CONFIG4:
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- gpmc,oe-on-ns: Assertion time
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- gpmc,oe-off-ns: Deassertion time
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- gpmc,oe-aad-mux-on-ns: Assertion time for AAD
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- gpmc,oe-aad-mux-off-ns: Deassertion time for AAD
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Access time and cycle time timings (in nanoseconds) corresponding to
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GPMC_CONFIG5:
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- gpmc,page-burst-access-ns: Multiple access word delay
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- gpmc,access-ns: Start-cycle to first data valid delay
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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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- gpmc,bus-turnaround-ns: Turn-around time between successive accesses
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- gpmc,cycle2cycle-delay-ns: Delay between chip-select pulses
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- gpmc,clk-activation-ns: GPMC clock activation time
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- gpmc,wait-monitoring-ns: Start of wait monitoring with regard to valid
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data
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Boolean timing parameters. If property is present parameter enabled and
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disabled if omitted:
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- gpmc,adv-extra-delay: ADV signal is delayed by half GPMC clock
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- gpmc,cs-extra-delay: CS signal is delayed by half GPMC clock
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- gpmc,cycle2cycle-diffcsen: Add "cycle2cycle-delay" between successive
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accesses to a different CS
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- gpmc,cycle2cycle-samecsen: Add "cycle2cycle-delay" between successive
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accesses to the same CS
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- gpmc,oe-extra-delay: OE signal is delayed by half GPMC clock
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- gpmc,we-extra-delay: WE signal is delayed by half GPMC clock
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- gpmc,time-para-granularity: Multiply all access times by 2
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The following are only applicable to OMAP3+ and AM335x:
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- gpmc,wr-access-ns: In synchronous write mode, for single or
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burst accesses, defines the number of
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GPMC_FCLK cycles from start access time
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to the GPMC_CLK rising edge used by the
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memory device for the first data capture.
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- gpmc,wr-data-mux-bus-ns: In address-data multiplex mode, specifies
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the time when the first data is driven on
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the address-data bus.
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GPMC chip-select settings properties for child nodes. All are optional.
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- gpmc,burst-length Page/burst length. Must be 4, 8 or 16.
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- gpmc,burst-wrap Enables wrap bursting
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- gpmc,burst-read Enables read page/burst mode
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- gpmc,burst-write Enables write page/burst mode
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- gpmc,device-width Total width of device(s) connected to a GPMC
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chip-select in bytes. The GPMC supports 8-bit
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and 16-bit devices and so this property must be
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1 or 2.
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- gpmc,mux-add-data Address and data multiplexing configuration.
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Valid values are 1 for address-address-data
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multiplexing mode and 2 for address-data
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multiplexing mode.
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- gpmc,sync-read Enables synchronous read. Defaults to asynchronous
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is this is not set.
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- gpmc,sync-write Enables synchronous writes. Defaults to asynchronous
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is this is not set.
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- gpmc,wait-pin Wait-pin used by client. Must be less than
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"gpmc,num-waitpins".
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- gpmc,wait-on-read Enables wait monitoring on reads.
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- gpmc,wait-on-write Enables wait monitoring on writes.
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Example for an AM33xx board:
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gpmc: gpmc@50000000 {
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compatible = "ti,am3352-gpmc";
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ti,hwmods = "gpmc";
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reg = <0x50000000 0x2000>;
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interrupts = <100>;
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dmas = <&edma 52 0>;
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dma-names = "rxtx";
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gpmc,num-cs = <8>;
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gpmc,num-waitpins = <2>;
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#address-cells = <2>;
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#size-cells = <1>;
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ranges = <0 0 0x08000000 0x10000000>; /* CS0 @addr 0x8000000, size 0x10000000 */
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interrupt-controller;
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#interrupt-cells = <2>;
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gpio-controller;
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#gpio-cells = <2>;
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/* child nodes go here */
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};
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