[PATCH v8 0/3] spi: support the SpacemiT K1 SPI controller

[Guodong Xu]

This series adds support for the SPI controller found in the SpacemiT
K1 SoC.  The driver currently supports only master mode.  The controller
has two 32-entry FIFOs and supports PIO and DMA for transfers.

Starting with v8, I am taking over from Alex Elder to shepherd this
series upstream.  Alex developed versions 1 through 7.

Version 8 reworks the driver based on Mark Brown's review of v7, making
much better use of the SPI core framework.

(Note, this is a distinct series from the QSPI driver, which was
merged recently.)

 -
 Guodong

Between version 7 and version 8:
  - Use // comments for the file header (Mark Brown)
  - Remove open-coded DMA mapping (k1_spi_map_dma_buffer(),
    k1_spi_unmap_dma_buffer(), k1_spi_map_dma_buffers(), the dummy
    buffer, k1_spi_io struct); use SPI core DMA mapping via
    transfer->tx_sg/rx_sg instead
  - Add can_dma() callback, replacing open-coded transfer length
    checks
  - Add set_cs() callback for chip select control via the
    TOP_HOLD_FRAME_LOW bit
  - Switch from transfer_one_message() to transfer_one()
  - DMA completion calls spi_finalize_current_transfer() directly
    instead of using a completion
  - Add SSP_STATUS_BCE (bit count error) to error detection
  - Return IRQ_NONE early if no transfer is active, before
    acknowledging interrupts
  - Simplify k1_spi_driver_data struct
  - ~160 fewer lines of code

Here is version 7 of this series:
  https://lore.kernel.org/lkml/20251114185745.2838358-1-elder@xxxxxxxxxxxx/

Between version 6 and version 7:
  - DIV_ROUND_UP_ULL() is now used when setting the speed, to address
    two errors reported by the Intel kernel test robot on 32-bit builds
  - Fixed a bug interpreting the resource pointer in k1_spi_dma_cleanup()
  - The driver is now built as a module by default, if ARCH_SPACEMIT
    is defined

Here is version 6 of this series:
  https://lore.kernel.org/lkml/20251027125504.297033-1-elder@xxxxxxxxxxxx/

Between version 5 and version 6:
  - Rebase only

Here is version 5 of this series:
  https://lore.kernel.org/lkml/20251013123309.2252042-1-elder@xxxxxxxxxxxx/

Between version 4 and version 5:
  - Added Yixun's Reviewed-by tag on patch 3

Here is version 4 of this series:
  https://lore.kernel.org/lkml/20250925121714.2514932-1-elder@xxxxxxxxxxxx/

Between version 3 and version 4 (all suggested by Yixun):
  - Fixed an underrun/overrun comment error
  - Renamed a pinctrl node
  - Formatted dmas and dma-names properties on one line

Here is version 3 of this series:
  https://lore.kernel.org/lkml/20250922161717.1590690-1-elder@xxxxxxxxxxxx/

Between version 2 and version 3:
  - Add Conor's Acked-by to patch 1
  - Add Rob's Reviewed-by to patch 1
  - Added imply_PDMA to the SPI_SPACEMIT_K1 Kconfig option
  - Fixed a bug pointed out by Vivian (and Troy) in word-sized reads
  - Added a comment stating we use 1, 2, or 4 bytes per word
  - Cleaned up DMA channels properly in case of failure setting up
  - No longer use devm_*() for allocating DMA channels or buffer
  - Moved the SPI controller into the dma-bus memory region

Here is version 2 of this series:
  https://lore.kernel.org/lkml/20250919155914.935608-1-elder@xxxxxxxxxxxx/

Between version 1 and version 2:
  - Use enum rather than const for the binding compatible string
  - Omit the label and status property in the binding example
  - The spi-spacemit-k1.o make target is now added in sorted order
  - The SPI_SPACEMIT_K1 config option is added in sorted order
  - The SPI_SPACEMIT_K1 config does *not* depend on MMP_PDMA,
    however MMP_PDMA is checked at runtime, and if not enabled,
    DMA will not be used
  - Read/modify/writes of registers no longer use an additional
    "virt" variable to hold the address accessed
  - The k1_spi_driver_data->ioaddr field has been renamed base
  - The DMA address for the base address is maintained, rather than
    saving the DMA address of the data register
  - The spi-max-frequency property value is now bounds checked
  - A local variable is now initialized to 0 in k1_spi_write_word()
  - The driver name is now "k1-spi"
  - DT aliases are used rather than spacemit,k1-ssp-id for bus number
  - The order of two pin control properties was changed as requested
  - Clock names and DMA names are now on one line in the "k1.dtsi"
  - The interrupts property is used rather than interrupts-extended

Here is version 1 of this series:
  https://lore.kernel.org/lkml/20250917220724.288127-1-elder@xxxxxxxxxxxx/

Alex Elder (3):
  dt-bindings: spi: add SpacemiT K1 SPI support
  spi: spacemit: introduce SpacemiT K1 SPI controller driver
  riscv: dts: spacemit: define a SPI controller node

Signed-off-by: Guodong Xu <guodong@xxxxxxxxxxxx>
---
Alex Elder (3):
      dt-bindings: spi: add SpacemiT K1 SPI support
      spi: spacemit: introduce SpacemiT K1 SPI controller driver
      riscv: dts: spacemit: define a SPI controller node

 .../devicetree/bindings/spi/spacemit,k1-spi.yaml   |  84 +++
 arch/riscv/boot/dts/spacemit/k1-bananapi-f3.dts    |   7 +
 arch/riscv/boot/dts/spacemit/k1-pinctrl.dtsi       |  20 +
 arch/riscv/boot/dts/spacemit/k1.dtsi               |  15 +
 drivers/spi/Kconfig                                |   9 +
 drivers/spi/Makefile                               |   1 +
 drivers/spi/spi-spacemit-k1.c                      | 782 +++++++++++++++++++++
 7 files changed, 918 insertions(+)
---
base-commit: 7aaa8047eafd0bd628065b15757d9b48c5f9c07d
change-id: 20260407-spi-spacemit-k1-e0957c311152

Best regards,
--  
Guodong Xu <guodong@xxxxxxxxxxxx>