[PATCH 0/8] spi: loongson: Fixes, cleanup and IRQ support

[Binbin Zhou <zhoubinbin@loongson.cn>]

Hi all:

This series fixes several long-standing bugs in the Loongson SPI
controller driver, cleans up the core driver, and adds interrupt-driven
transfers with a polling fallback.

The series is grouped as follows:

  Bug fixes (suitable for stable):
    1. Fix the SPI mode caching logic so mode bits can be cleared.
    2. Fix the chip-select idle level for SPI_CS_HIGH devices.
    3. Separate PM register state from runtime register usage.
    4. Fix the clock divider calculation with an explicit divider table.

  Robustness and cleanup:
    5. Support the ACPI "clock-frequency" property and validate the
       input clock rate during probe.
    6. Move private register definitions and the private controller
       structure into the core driver.
    7. Convert the driver to the regmap-mmio API.

  New feature:
    8. Add interrupt-driven transfers, keeping polling as a fallback
       when no IRQ is available.

The IRQ path also brings a significant performance improvement. On a
Loongson-2K3000 board, reading SPI flash with dd improved from about
50 kB/s in polling mode to about 382 kB/s with IRQ-driven transfers,
roughly 7.6x faster.

Binbin.
Thanks.

Binbin Zhou (8):
  spi: loongson: Fix incorrect SPI mode caching logic
  spi: loongson: Fix CS idle state for SPI_CS_HIGH devices
  spi: loongson: Make suspend/resume registers PM-specific
  spi: loongson: Fix clock divider calculation with explicit table
  spi: loongson: Support ACPI clock-frequency and add error handling
  spi: loongson: Move private definitions into the core driver
  spi: loongson: Convert to regmap API
  spi: loongson: Add interrupt support for SPI controller

 drivers/spi/spi-loongson-core.c | 566 ++++++++++++++++++++++++--------
 drivers/spi/spi-loongson-pci.c  |  25 +-
 drivers/spi/spi-loongson-plat.c |  17 +-
 drivers/spi/spi-loongson.h      |  48 +--
 4 files changed, 457 insertions(+), 199 deletions(-)


base-commit: 8ab8c079820e6134bc0d8c312244644afb66ae9c
-- 
2.52.0