The Xilinx QSPI controller has two advanced modes which allow the
controller to behave differently and consider two flashes as one single
storage.
One of these two modes is quite complex to support from a binding point
of view and is the dual parallel memories. In this mode, each byte of
data is stored in both devices: the even bits in one, the odd bits in
the other. The split is automatically handled by the QSPI controller and
is transparent for the user.
The other mode is simpler to support, it is called dual stacked
memories. The controller shares the same SPI bus but each of the devices
contain half of the data. Once in this mode, the controller does not
follow CS requests but instead internally wires the two CS levels with
the value of the most significant address bit.
Supporting these two modes will involve core changes which include the
possibility of providing two CS for a single SPI device
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Acked-by: Rob Herring <robh@kernel.org>
Reviewed-by: Pratyush Yadav <p.yadav@ti.com>
Link: https://lore.kernel.org/r/20220126112608.955728-2-miquel.raynal@bootlin.com
Signed-off-by: Mark Brown <broonie@kernel.org>
The spi-peripheral-props.yaml schema contains peripheral-specific
properties for SPI controllers that should be present in the peripheral
node. Add a reference to that so its constraints are followed.
additionalProperties: false cannot be used since it marks the controller
properties as unknown. Use unevaluatedProperties: false instead. This
has the side effect of allowing extra properties that are not specified
in the schema. The alternative is to list all the controller properties
in this schema but that would mean every peripheral binding would have
to repeat the same set of properties for each controller.
Signed-off-by: Pratyush Yadav <p.yadav@ti.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20211109181911.2251-4-p.yadav@ti.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Convert the SPI-NOR binding to DT schema format. Like other memory chips,
the compatible strings are a mess with vendor prefixes not being used
consistently and some compatibles not documented. The resulting schema
passes on 'compatible' checks for most in tree users with the exception
of some oddballs.
I dropped the 'm25p.*-nonjedec' compatible strings as these don't appear
to be used anywhere.
Cc: Miquel Raynal <miquel.raynal@bootlin.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Vignesh Raghavendra <vigneshr@ti.com>
Cc: linux-mtd@lists.infradead.org
Signed-off-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20210202175340.3902494-1-robh@kernel.org
