[PATCH v8 0/2] spi: cadence-quadpsi: Add support for the Cadence QSPI controller

[Ramuthevar,Vadivel MuruganX]

Add support for the Cadence QSPI controller. This controller is
present in the Intel Lightning Mountain(LGM) SoCs, Altera and TI SoCs.
This driver has been tested on the Intel LGM SoCs.

This driver does not support generic SPI and also the implementation
only supports spi-mem interface to replace the existing driver in
mtd/spi-nor/cadence-quadspi.c, the existing driver only support SPI-NOR
flash memory.

Thanks Vignesh for the review, modify, test and confirm the patch
which is based on spi-mem based cadence driver working on TI's platform.
after few changes started working on Intel's platform as well.

changes from v7:
 -- remove addr_buf kept like as original
 -- drop bus-num, chipselect variable
 -- add soc_selection varible to differetiate the features
 -- replace dev->ddev in dma function
 -- add seperate function to handle the 24bit slave device address 
    translation for lgm soc
 -- correct sentence seems incomplete in Kconfig
 -- add cqspi->soc_selection check to keep the original TI platform
    working code.
    
changes from v6:
 -- Add the Signed-off-by Vignesh in commit message
 -- bus_num, num_chipselect added to avoid the garbage bus number
    during the probe and spi_register.
 -- master mode bits updated
 -- address sequence is different from TI and Intel SoC Ip handling
    so modified as per Intel and differentiating by use_dac_mode variable.
 -- dummy cycles also different b/w two platforms, so keeping separate check
 -- checkpatch errors which are intentional left as is for better readability

changes from v5:
 -- kbuild test robot warnings fixed
 -- Add Reported-By: Dan Carpenter <dan.carpenter@xxxxxxxxxx>

changes from v4:
 -- kbuild test robot warnings fixed
 -- Add Reborted-by: tag

changes from v3:
spi-cadence-quadspi.c
 -- static to all functions wrt to local to the file.
 -- Prefix cqspi_ and make the function static
 -- cmd_ops, data_ops and dummy_ops dropped
 -- addr_ops kept since it is required for address calculation.
 -- devm_ used for supported functions , removed legacy API's
 -- removed "indirect" name from functions
 -- replaced by master->mode_bits = SPI_RX_QUAD | SPI_TX_DUAL | SPI_RX_DUAL | SPI_RX_OCTAL;
    as per Vignesh susggestion
 -- removed free functions since devm_ handles automatically.
 -- dropped all unused Macros

YAML file update:
 -- cadence,qspi.yaml file name replace by cdns,qspi-nor.yaml
 -- compatible string updated as per Vignesh suggestion
 -- for single entry, removed descriptions
 -- removed optional parameters
  Build Result:
   linux$ make DT_SCHEMA_FILES=Documentation/devicetree/bindings/spi/cdns,qspi-nor.yaml dt_binding_check
    CHKDT   Documentation/devicetree/bindings/spi/cdns,qspi-nor.yaml
    SCHEMA  Documentation/devicetree/bindings/processed-schema.yaml
    DTC     Documentation/devicetree/bindings/spi/cdns,qspi-nor.example.dt.yaml
    CHECK   Documentation/devicetree/bindings/spi/cdns,qspi-nor.example.dt.yaml

Ramuthevar Vadivel Murugan (2):
  dt-bindings: spi: Add schema for Cadence QSPI Controller driver
  spi: cadence-quadpsi: Add support for the Cadence QSPI controller

 .../devicetree/bindings/spi/cdns,qspi-nor.yaml     |  147 ++
 drivers/spi/Kconfig                                |    9 +
 drivers/spi/Makefile                               |    1 +
 drivers/spi/spi-cadence-quadspi.c                  | 1510 ++++++++++++++++++++
 4 files changed, 1667 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/spi/cdns,qspi-nor.yaml
 create mode 100644 drivers/spi/spi-cadence-quadspi.c

-- 
2.11.0