4b0cb4e7ab
Most SPI NOR devices do not require a specific compatible, their ID can in general be discovered with the JEDEC READ ID opcode. In this case, only the "jedec,spi-nor" generic compatible is expected. Clarify this information in the compatible description to (i) help device-tree writers and (ii) prevent further attempts to extend this list with useless information. Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com> Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org> Link: https://lore.kernel.org/r/20230616140054.2788684-1-miquel.raynal@bootlin.com [ta: s/JEDEC/JEDEC SFDP for clarity and s/JEDEC READ ID/READ ID as the opcode is not part of the JEDEC SFDP standard.] Signed-off-by: Tudor Ambarus <tudor.ambarus@linaro.org>
121 lines
4.2 KiB
YAML
121 lines
4.2 KiB
YAML
# SPDX-License-Identifier: GPL-2.0-only
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%YAML 1.2
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---
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$id: http://devicetree.org/schemas/mtd/jedec,spi-nor.yaml#
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$schema: http://devicetree.org/meta-schemas/core.yaml#
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title: SPI NOR flash ST M25Pxx (and similar) serial flash chips
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maintainers:
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- Rob Herring <robh@kernel.org>
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allOf:
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- $ref: mtd.yaml#
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- $ref: /schemas/spi/spi-peripheral-props.yaml#
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properties:
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compatible:
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oneOf:
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- items:
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- pattern: "^((((micron|spansion|st),)?\
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(m25p(40|80|16|32|64|128)|\
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n25q(32b|064|128a11|128a13|256a|512a|164k)))|\
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atmel,at25df(321a|641|081a)|\
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everspin,mr25h(10|40|128|256)|\
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(mxicy|macronix),mx25l(4005a|1606e|6405d|8005|12805d|25635e)|\
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(mxicy|macronix),mx25u(4033|4035)|\
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(spansion,)?s25fl(128s|256s1|512s|008k|064k|164k)|\
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(sst|microchip),sst25vf(016b|032b|040b)|\
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(sst,)?sst26wf016b|\
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(sst,)?sst25wf(040b|080)|\
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winbond,w25x(80|32)|\
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(winbond,)?w25q(16|32(w|dw)?|64(dw)?|80bl|128(fw)?|256))$"
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- const: jedec,spi-nor
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- items:
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- enum:
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- issi,is25lp016d
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- micron,mt25qu02g
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- mxicy,mx25r1635f
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- mxicy,mx25u6435f
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- mxicy,mx25v8035f
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- spansion,s25sl12801
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- spansion,s25fs512s
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- const: jedec,spi-nor
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- const: jedec,spi-nor
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description:
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SPI NOR flashes compatible with the JEDEC SFDP standard or which may be
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identified with the READ ID opcode (0x9F) do not deserve a specific
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compatible. They should instead only be matched against the generic
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"jedec,spi-nor" compatible.
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reg:
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minItems: 1
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maxItems: 2
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m25p,fast-read:
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type: boolean
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description:
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Use the "fast read" opcode to read data from the chip instead of the usual
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"read" opcode. This opcode is not supported by all chips and support for
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it can not be detected at runtime. Refer to your chips' datasheet to check
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if this is supported by your chip.
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broken-flash-reset:
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type: boolean
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description:
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Some flash devices utilize stateful addressing modes (e.g., for 32-bit
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addressing) which need to be managed carefully by a system. Because these
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sorts of flash don't have a standardized software reset command, and
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because some systems don't toggle the flash RESET# pin upon system reset
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(if the pin even exists at all), there are systems which cannot reboot
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properly if the flash is left in the "wrong" state. This boolean flag can
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be used on such systems, to denote the absence of a reliable reset
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mechanism.
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no-wp:
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type: boolean
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description:
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The status register write disable (SRWD) bit in status register, combined
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with the WP# signal, provides hardware data protection for the device. When
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the SRWD bit is set to 1, and the WP# signal is either driven LOW or hard
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strapped to LOW, the status register nonvolatile bits become read-only and
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the WRITE STATUS REGISTER operation will not execute. The only way to exit
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this hardware-protected mode is to drive WP# HIGH. If the WP# signal of the
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flash device is not connected or is wrongly tied to GND (that includes internal
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pull-downs) then status register permanently becomes read-only as the SRWD bit
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cannot be reset. This boolean flag can be used on such systems to avoid setting
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the SRWD bit while writing the status register. WP# signal hard strapped to GND
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can be a valid use case.
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reset-gpios:
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description:
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A GPIO line connected to the RESET (active low) signal of the device.
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If "broken-flash-reset" is present then having this property does not
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make any difference.
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spi-cpol: true
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spi-cpha: true
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dependencies:
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spi-cpol: [ spi-cpha ]
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spi-cpha: [ spi-cpol ]
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unevaluatedProperties: false
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examples:
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- |
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#include <dt-bindings/gpio/gpio.h>
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spi {
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#address-cells = <1>;
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#size-cells = <0>;
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flash@0 {
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compatible = "spansion,m25p80", "jedec,spi-nor";
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reg = <0>;
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spi-max-frequency = <40000000>;
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m25p,fast-read;
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reset-gpios = <&gpio 12 GPIO_ACTIVE_LOW>;
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};
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};
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...
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