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SPI NOR flashes have specific cs-setup time requirements without which they can't work at frequencies close to their maximum supported frequency, as they miss the first bits of the instruction command. Unrecognized commands are ignored, thus the flash will be unresponsive. Introduce the spi-cs-setup-ns property to allow spi devices to specify their cs setup time. Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com> Link: https://lore.kernel.org/r/20221117105249.115649-2-tudor.ambarus@microchip.com Signed-off-by: Mark Brown <broonie@kernel.org>
113 lines
3.8 KiB
YAML
113 lines
3.8 KiB
YAML
# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
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%YAML 1.2
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---
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$id: http://devicetree.org/schemas/spi/spi-peripheral-props.yaml#
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$schema: http://devicetree.org/meta-schemas/core.yaml#
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title: Peripheral-specific properties for a SPI bus.
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description:
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Many SPI controllers need to add properties to peripheral devices. They could
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be common properties like spi-max-frequency, spi-cpha, etc. or they could be
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controller specific like delay in clock or data lines, etc. These properties
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need to be defined in the peripheral node because they are per-peripheral and
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there can be multiple peripherals attached to a controller. All those
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properties are listed here. The controller specific properties should go in
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their own separate schema that should be referenced from here.
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maintainers:
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- Mark Brown <broonie@kernel.org>
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properties:
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reg:
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minItems: 1
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maxItems: 256
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items:
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items:
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- minimum: 0
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maximum: 256
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description:
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Chip select used by the device.
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spi-cs-high:
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$ref: /schemas/types.yaml#/definitions/flag
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description:
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The device requires the chip select active high.
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spi-lsb-first:
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$ref: /schemas/types.yaml#/definitions/flag
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description:
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The device requires the LSB first mode.
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spi-max-frequency:
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$ref: /schemas/types.yaml#/definitions/uint32
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description:
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Maximum SPI clocking speed of the device in Hz.
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spi-cs-setup-ns:
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description:
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Delay in nanosecods to be introduced by the controller after CS is
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asserted.
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spi-rx-bus-width:
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description:
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Bus width to the SPI bus used for read transfers.
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If 0 is provided, then no RX will be possible on this device.
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$ref: /schemas/types.yaml#/definitions/uint32
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enum: [0, 1, 2, 4, 8]
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default: 1
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spi-rx-delay-us:
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description:
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Delay, in microseconds, after a read transfer.
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rx-sample-delay-ns:
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description: SPI Rx sample delay offset, unit is nanoseconds.
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The delay from the default sample time before the actual
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sample of the rxd input signal occurs.
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spi-tx-bus-width:
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description:
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Bus width to the SPI bus used for write transfers.
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If 0 is provided, then no TX will be possible on this device.
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$ref: /schemas/types.yaml#/definitions/uint32
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enum: [0, 1, 2, 4, 8]
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default: 1
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spi-tx-delay-us:
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description:
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Delay, in microseconds, after a write transfer.
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stacked-memories:
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description: Several SPI memories can be wired in stacked mode.
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This basically means that either a device features several chip
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selects, or that different devices must be seen as a single
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bigger chip. This basically doubles (or more) the total address
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space with only a single additional wire, while still needing
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to repeat the commands when crossing a chip boundary. The size of
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each chip should be provided as members of the array.
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$ref: /schemas/types.yaml#/definitions/uint64-array
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minItems: 2
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maxItems: 4
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parallel-memories:
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description: Several SPI memories can be wired in parallel mode.
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The devices are physically on a different buses but will always
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act synchronously as each data word is spread across the
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different memories (eg. even bits are stored in one memory, odd
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bits in the other). This basically doubles the address space and
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the throughput while greatly complexifying the wiring because as
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many busses as devices must be wired. The size of each chip should
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be provided as members of the array.
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$ref: /schemas/types.yaml#/definitions/uint64-array
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minItems: 2
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maxItems: 4
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# The controller specific properties go here.
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allOf:
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- $ref: cdns,qspi-nor-peripheral-props.yaml#
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- $ref: samsung,spi-peripheral-props.yaml#
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- $ref: nvidia,tegra210-quad-peripheral-props.yaml#
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additionalProperties: true
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