spi: cadence-qspi: set maximum chip-select to 4

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Change the maximum chip-select count in cadence-qspi to 4 instead of 16.
The value gets used as default ->num_chipselect when the num-cs DT
property isn't received from devicetree. It also determines the
cqspi->f_pdata array size.

Hardware only supports values up to 4; see cqspi_chipselect() that sets
CS using a one-bit-per-CS 4-bit register field.

Add a static_assert() call as a defensive measure to ensure we stay
under the SPI subsystem limit. It got set to 4 when introduced in
4d8ff6b099 ("spi: Add multi-cs memories support in SPI core") and
later increased to 16 in 2f8c7c3715 ("spi: Raise limit on number of
chip selects").

Signed-off-by: Théo Lebrun <theo.lebrun@bootlin.com>
Link: https://msgid.link/r/20240209-cdns-qspi-cs-v1-2-a4f9dfed9ab4@bootlin.com
Signed-off-by: Mark Brown <broonie@kernel.org>

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Théo Lebrun 2024-02-09 14:45:31 +01:00 • committed by Mark Brown

parent 0d62c64a8e

commit 7cc3522aed

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drivers/spi/spi-cadence-quadspi.c

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