bc6b1e7b86
This patch adds basic DT bindings for OMAP GPMC. The actual peripherals are instantiated from child nodes within the GPMC node, and the only type of device that is currently supported is NAND. Code was added to parse the generic GPMC timing parameters and some documentation with examples on how to use them. Successfully tested on an AM33xx board. Signed-off-by: Daniel Mack <zonque@gmail.com> Acked-by: Grant Likely <grant.likely@secretlab.ca> [tony@atomide.com: updated to apply] Signed-off-by: Tony Lindgren <tony@atomide.com>
85 lines
2.7 KiB
Plaintext
85 lines
2.7 KiB
Plaintext
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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Timing properties for child nodes. All are optional and default to 0.
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- gpmc,sync-clk: Minimum clock period for synchronous mode, in picoseconds
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Chip-select signal timings corresponding to GPMC_CONFIG2:
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- gpmc,cs-on: Assertion time
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- gpmc,cs-rd-off: Read deassertion time
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- gpmc,cs-wr-off: Write deassertion time
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ADV signal timings corresponding to GPMC_CONFIG3:
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- gpmc,adv-on: Assertion time
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- gpmc,adv-rd-off: Read deassertion time
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- gpmc,adv-wr-off: Write deassertion time
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WE signals timings corresponding to GPMC_CONFIG4:
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- gpmc,we-on: Assertion time
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- gpmc,we-off: Deassertion time
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OE signals timings corresponding to GPMC_CONFIG4:
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- gpmc,oe-on: Assertion time
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- gpmc,oe-off: Deassertion time
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Access time and cycle time timings corresponding to GPMC_CONFIG5:
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- gpmc,page-burst-access: Multiple access word delay
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- gpmc,access: Start-cycle to first data valid delay
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- gpmc,rd-cycle: Total read cycle time
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- gpmc,wr-cycle: Total write cycle time
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The following are only applicable to OMAP3+ and AM335x:
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- gpmc,wr-access
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- gpmc,wr-data-mux-bus
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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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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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/* child nodes go here */
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};
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