[PATCH 0/3] spi: spi-cadence-quadspi: Add Rx tuning support for DTR mode

[Sai Krishna Potthuri]

Enable PHY and DQS required for Xilinx Versal Octal SPI to operate in DTR
protocol.
Add and update device_id field in spi_mem structure with flash id
information. Xilinx Versal Octal SPI driver requires the device id
information to perform the Rx tuning operation. Since there is no common
Tuning Data Pattern defined across all vendors, controllers like Xilinx
Versal Octal SPI which requires Rx tuning to find out the optimal sampling
point for data lines, this device id information will be used as a golden
data.
The reason behind choosing this approach instead of reading the ID again
in the controller driver is to make it generic solution.
- Other controller drivers which want to use similar tuning process, they
will make use of this ID instead of reading the ID again in the driver.
- Also, we can avoid hardcoding the command information and initiating the
transfer in the controller driver as this should happen from spi-nor.

Sai Krishna Potthuri (3):
  spi: cadence-quadspi: Add support for PHY module and DQS
  mtd: spi-nor: Add and update device_id field in spi_mem structure
  spi: cadence-quadspi: Add Rx tuning support for Xilinx Versal OSPI

 drivers/mtd/spi-nor/core.c        |   1 +
 drivers/spi/spi-cadence-quadspi.c | 226 +++++++++++++++++++++++++++++-
 include/linux/spi/spi-mem.h       |   4 +
 3 files changed, 230 insertions(+), 1 deletion(-)

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2.25.1