[PATCH 0/7] spi: cadence-quadspi: Add Octal DTR support

[Pratyush Yadav]

Hi,

This series adds support for Octal DTR mode now that SPI NOR supports
these flashes. Patches 1/7 to 4/7 and 6/7 fix some minor bugs and issues.
Patche 5/7 lays some groundwork by implementing the supports_op() hook.
Patch 7/7 adds the Octal DTR mode support.

While the main aim of this series is to support 8D-8D-8D mode, other
modes like 4D-4D-4D or 2S-2S-2S should also now be supported, though
they have not been tested.

Tested on J721E with Micron MT35XU512ABA and on J7200 with Cypress
S28HS512T. Tested on J721E with Micron MT25QU512A (1S-1S-4S) for
regressions.

Pratyush Yadav (7):
  spi: cadence-quadspi: Set master max_speed_hz
  spi: cadence-quadspi: Abort read if dummy cycles required are too many
  spi: cadence-quadspi: Set dummy cycles from STIG commands
  spi: cadence-quadspi: Fix dummy cycle calculation when buswidth > 1
  spi: cadence-quadspi: Implement a simple supports_op hook
  spi: cadence-quadspi: Wait at least 500 ms for direct reads
  spi: cadence-quadspi: Add DTR support

 drivers/spi/spi-cadence-quadspi.c | 364 ++++++++++++++++++++++++++----
 1 file changed, 325 insertions(+), 39 deletions(-)

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2.28.0