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diff --git a/Documentation/devicetree/bindings/bus/ti-gpmc.txt b/Documentation/devicetree/bindings/bus/ti-gpmc.txt new file mode 100644 index 000000000..704be9306 --- /dev/null +++ b/Documentation/devicetree/bindings/bus/ti-gpmc.txt @@ -0,0 +1,130 @@ +Device tree bindings for OMAP general purpose memory controllers (GPMC) + +The actual devices are instantiated from the child nodes of a GPMC node. + +Required properties: + + - compatible: Should be set to one of the following: + + ti,omap2420-gpmc (omap2420) + ti,omap2430-gpmc (omap2430) + ti,omap3430-gpmc (omap3430 & omap3630) + ti,omap4430-gpmc (omap4430 & omap4460 & omap543x) + ti,am3352-gpmc (am335x devices) + + - reg: A resource specifier for the register space + (see the example below) + - ti,hwmods: Should be set to "ti,gpmc" until the DT transition is + completed. + - #address-cells: Must be set to 2 to allow memory address translation + - #size-cells: Must be set to 1 to allow CS address passing + - gpmc,num-cs: The maximum number of chip-select lines that controller + can support. + - gpmc,num-waitpins: The maximum number of wait pins that controller can + support. + - ranges: Must be set up to reflect the memory layout with four + integer values for each chip-select line in use: + + <cs-number> 0 <physical address of mapping> <size> + + Currently, calculated values derived from the contents + of the per-CS register GPMC_CONFIG7 (as set up by the + bootloader) are used for the physical address decoding. + As this will change in the future, filling correct + values here is a requirement. + +Timing properties for child nodes. All are optional and default to 0. + + - gpmc,sync-clk-ps: Minimum clock period for synchronous mode, in picoseconds + + Chip-select signal timings (in nanoseconds) corresponding to GPMC_CONFIG2: + - gpmc,cs-on-ns: Assertion time + - gpmc,cs-rd-off-ns: Read deassertion time + - gpmc,cs-wr-off-ns: Write deassertion time + + ADV signal timings (in nanoseconds) corresponding to GPMC_CONFIG3: + - gpmc,adv-on-ns: Assertion time + - gpmc,adv-rd-off-ns: Read deassertion time + - gpmc,adv-wr-off-ns: Write deassertion time + + WE signals timings (in nanoseconds) corresponding to GPMC_CONFIG4: + - gpmc,we-on-ns Assertion time + - gpmc,we-off-ns: Deassertion time + + OE signals timings (in nanoseconds) corresponding to GPMC_CONFIG4: + - gpmc,oe-on-ns: Assertion time + - gpmc,oe-off-ns: Deassertion time + + Access time and cycle time timings (in nanoseconds) corresponding to + GPMC_CONFIG5: + - gpmc,page-burst-access-ns: Multiple access word delay + - gpmc,access-ns: Start-cycle to first data valid delay + - gpmc,rd-cycle-ns: Total read cycle time + - gpmc,wr-cycle-ns: Total write cycle time + - gpmc,bus-turnaround-ns: Turn-around time between successive accesses + - gpmc,cycle2cycle-delay-ns: Delay between chip-select pulses + - gpmc,clk-activation-ns: GPMC clock activation time + - gpmc,wait-monitoring-ns: Start of wait monitoring with regard to valid + data + +Boolean timing parameters. If property is present parameter enabled and +disabled if omitted: + - gpmc,adv-extra-delay: ADV signal is delayed by half GPMC clock + - gpmc,cs-extra-delay: CS signal is delayed by half GPMC clock + - gpmc,cycle2cycle-diffcsen: Add "cycle2cycle-delay" between successive + accesses to a different CS + - gpmc,cycle2cycle-samecsen: Add "cycle2cycle-delay" between successive + accesses to the same CS + - gpmc,oe-extra-delay: OE signal is delayed by half GPMC clock + - gpmc,we-extra-delay: WE signal is delayed by half GPMC clock + - gpmc,time-para-granularity: Multiply all access times by 2 + +The following are only applicable to OMAP3+ and AM335x: + - gpmc,wr-access-ns: In synchronous write mode, for single or + burst accesses, defines the number of + GPMC_FCLK cycles from start access time + to the GPMC_CLK rising edge used by the + memory device for the first data capture. + - gpmc,wr-data-mux-bus-ns: In address-data multiplex mode, specifies + the time when the first data is driven on + the address-data bus. + +GPMC chip-select settings properties for child nodes. All are optional. + +- gpmc,burst-length Page/burst length. Must be 4, 8 or 16. +- gpmc,burst-wrap Enables wrap bursting +- gpmc,burst-read Enables read page/burst mode +- gpmc,burst-write Enables write page/burst mode +- gpmc,device-width Total width of device(s) connected to a GPMC + chip-select in bytes. The GPMC supports 8-bit + and 16-bit devices and so this property must be + 1 or 2. +- gpmc,mux-add-data Address and data multiplexing configuration. + Valid values are 1 for address-address-data + multiplexing mode and 2 for address-data + multiplexing mode. +- gpmc,sync-read Enables synchronous read. Defaults to asynchronous + is this is not set. +- gpmc,sync-write Enables synchronous writes. Defaults to asynchronous + is this is not set. +- gpmc,wait-pin Wait-pin used by client. Must be less than + "gpmc,num-waitpins". +- gpmc,wait-on-read Enables wait monitoring on reads. +- gpmc,wait-on-write Enables wait monitoring on writes. + +Example for an AM33xx board: + + gpmc: gpmc@50000000 { + compatible = "ti,am3352-gpmc"; + ti,hwmods = "gpmc"; + reg = <0x50000000 0x2000>; + interrupts = <100>; + + gpmc,num-cs = <8>; + gpmc,num-waitpins = <2>; + #address-cells = <2>; + #size-cells = <1>; + ranges = <0 0 0x08000000 0x10000000>; /* CS0 @addr 0x8000000, size 0x10000000 */ + + /* child nodes go here */ + }; |