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GPMC stands for General Purpose Memory Controller and it is present on many Texas Instruments SoCs. It supports a number of Asynchronous and Synchronous interfaces and has various settings to configure the bus interface. The DT bindings define all the various GPMC settings. As the GPMC supports multiple devices on the bus, each device is represented as a child and the respective GPMC settings are situated there. (see ti,gpmc-child.yaml) These binding docs are picked up from the Linux kernel. Signed-off-by: Roger Quadros <rogerq@kernel.org>
252 lines
6.4 KiB
YAML
252 lines
6.4 KiB
YAML
# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
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%YAML 1.2
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---
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$id: http://devicetree.org/schemas/memory-controllers/ti,gpmc-child.yaml#
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$schema: http://devicetree.org/meta-schemas/core.yaml#
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title: device tree bindings for children of the Texas Instruments GPMC
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maintainers:
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- Tony Lindgren <tony@atomide.com>
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- Roger Quadros <rogerq@kernel.org>
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description:
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This binding is meant for the child nodes of the GPMC node. The node
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represents any device connected to the GPMC bus. It may be a Flash chip,
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RAM chip or Ethernet controller, etc. These properties are meant for
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configuring the GPMC settings/timings and will accompany the bindings
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supported by the respective device.
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properties:
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reg: true
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# GPMC Timing properties for child nodes. All are optional and default to 0.
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gpmc,sync-clk-ps:
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description: Minimum clock period for synchronous mode
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default: 0
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# Chip-select signal timings corresponding to GPMC_CONFIG2:
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gpmc,cs-on-ns:
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description: Assertion time
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default: 0
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gpmc,cs-rd-off-ns:
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description: Read deassertion time
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default: 0
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gpmc,cs-wr-off-ns:
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description: Write deassertion time
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default: 0
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# ADV signal timings corresponding to GPMC_CONFIG3:
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gpmc,adv-on-ns:
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description: Assertion time
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default: 0
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gpmc,adv-rd-off-ns:
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description: Read deassertion time
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default: 0
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gpmc,adv-wr-off-ns:
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description: Write deassertion time
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default: 0
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gpmc,adv-aad-mux-on-ns:
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description: Assertion time for AAD
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default: 0
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gpmc,adv-aad-mux-rd-off-ns:
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description: Read deassertion time for AAD
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default: 0
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gpmc,adv-aad-mux-wr-off-ns:
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description: Write deassertion time for AAD
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default: 0
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# WE signals timings corresponding to GPMC_CONFIG4:
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gpmc,we-on-ns:
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description: Assertion time
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default: 0
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gpmc,we-off-ns:
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description: Deassertion time
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default: 0
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# OE signals timings corresponding to GPMC_CONFIG4:
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gpmc,oe-on-ns:
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description: Assertion time
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default: 0
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gpmc,oe-off-ns:
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description: Deassertion time
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default: 0
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gpmc,oe-aad-mux-on-ns:
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description: Assertion time for AAD
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default: 0
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gpmc,oe-aad-mux-off-ns:
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description: Deassertion time for AAD
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default: 0
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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:
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description: Multiple access word delay
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default: 0
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gpmc,access-ns:
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description: Start-cycle to first data valid delay
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default: 0
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gpmc,rd-cycle-ns:
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description: Total read cycle time
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default: 0
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gpmc,wr-cycle-ns:
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description: Total write cycle time
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default: 0
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gpmc,bus-turnaround-ns:
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description: Turn-around time between successive accesses
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default: 0
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gpmc,cycle2cycle-delay-ns:
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description: Delay between chip-select pulses
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default: 0
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gpmc,clk-activation-ns:
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description: GPMC clock activation time
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default: 0
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gpmc,wait-monitoring-ns:
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description: Start of wait monitoring with regard to valid data
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default: 0
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# Boolean timing parameters. If property is present, parameter is enabled
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# otherwise disabled.
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gpmc,adv-extra-delay:
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description: ADV signal is delayed by half GPMC clock
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type: boolean
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gpmc,cs-extra-delay:
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description: CS signal is delayed by half GPMC clock
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type: boolean
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gpmc,cycle2cycle-diffcsen:
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description: |
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Add "cycle2cycle-delay" between successive accesses
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to a different CS
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type: boolean
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gpmc,cycle2cycle-samecsen:
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description: |
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Add "cycle2cycle-delay" between successive accesses
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to the same CS
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type: boolean
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gpmc,oe-extra-delay:
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description: OE signal is delayed by half GPMC clock
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type: boolean
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gpmc,we-extra-delay:
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description: WE signal is delayed by half GPMC clock
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type: boolean
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gpmc,time-para-granularity:
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description: Multiply all access times by 2
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type: boolean
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# The following two properties are applicable only to OMAP3+ and AM335x:
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gpmc,wr-access-ns:
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description: |
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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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default: 0
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gpmc,wr-data-mux-bus-ns:
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description: |
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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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default: 0
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# GPMC chip-select settings properties for child nodes. All are optional.
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gpmc,burst-length:
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description: Page/burst length.
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$ref: /schemas/types.yaml#/definitions/uint32
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enum: [0, 4, 8, 16]
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default: 0
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gpmc,burst-wrap:
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description: Enables wrap bursting
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type: boolean
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gpmc,burst-read:
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description: Enables read page/burst mode
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type: boolean
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gpmc,burst-write:
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description: Enables write page/burst mode
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type: boolean
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gpmc,device-width:
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description: |
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Total width of device(s) connected to a GPMC
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chip-select in bytes. The GPMC supports 8-bit
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and 16-bit devices and so this property must be
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1 or 2.
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$ref: /schemas/types.yaml#/definitions/uint32
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enum: [1, 2]
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default: 1
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gpmc,mux-add-data:
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description: |
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Address and data multiplexing configuration.
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Valid values are
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0 for Non multiplexed mode
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1 for address-address-data multiplexing mode and
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2 for address-data multiplexing mode.
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$ref: /schemas/types.yaml#/definitions/uint32
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enum: [0, 1, 2]
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gpmc,sync-read:
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description: |
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Enables synchronous read. Defaults to asynchronous
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is this is not set.
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type: boolean
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gpmc,sync-write:
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description: |
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Enables synchronous writes. Defaults to asynchronous
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is this is not set.
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type: boolean
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gpmc,wait-pin:
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description: |
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Wait-pin used by client. Must be less than "gpmc,num-waitpins".
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$ref: /schemas/types.yaml#/definitions/uint32
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gpmc,wait-pin-polarity:
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description: |
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Set the desired polarity for the selected wait pin.
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0 for active low, 1 for active high.
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$ref: /schemas/types.yaml#/definitions/uint32
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enum: [0, 1]
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gpmc,wait-on-read:
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description: Enables wait monitoring on reads.
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type: boolean
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gpmc,wait-on-write:
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description: Enables wait monitoring on writes.
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type: boolean
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required:
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- reg
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# the GPMC child will have its own native properties
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additionalProperties: true
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