| 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: Minimum clock period for synchronous mode, in picoseconds |
| |
| Chip-select signal timings corresponding to GPMC_CONFIG2: |
| - gpmc,cs-on: Assertion time |
| - gpmc,cs-rd-off: Read deassertion time |
| - gpmc,cs-wr-off: Write deassertion time |
| |
| ADV signal timings corresponding to GPMC_CONFIG3: |
| - gpmc,adv-on: Assertion time |
| - gpmc,adv-rd-off: Read deassertion time |
| - gpmc,adv-wr-off: Write deassertion time |
| |
| WE signals timings corresponding to GPMC_CONFIG4: |
| - gpmc,we-on: Assertion time |
| - gpmc,we-off: Deassertion time |
| |
| OE signals timings corresponding to GPMC_CONFIG4: |
| - gpmc,oe-on: Assertion time |
| - gpmc,oe-off: Deassertion time |
| |
| Access time and cycle time timings corresponding to GPMC_CONFIG5: |
| - gpmc,page-burst-access: Multiple access word delay |
| - gpmc,access: Start-cycle to first data valid delay |
| - gpmc,rd-cycle: Total read cycle time |
| - gpmc,wr-cycle: Total write cycle time |
| |
| The following are only applicable to OMAP3+ and AM335x: |
| - gpmc,wr-access |
| - gpmc,wr-data-mux-bus |
| |
| |
| 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 */ |
| }; |