[PATCH V4 0/5] i2c: ls2x: Add support for the Loongson-2K/LS7A I2C controller

[Binbin Zhou <zhoubinbin@loongson.cn>]

Hi all:

This patch series adds support for the I2C module found on various
Loongson systems with the Loongson-2K SoC or the Loongson LS7A bridge chip.

For now, the I2C driver is suitable for DT-based or ACPI-based systems.

I have tested on Loongson-3A5000LA+LS7A1000/LS7A2000, Loongson-2K1000LA
and Loongson-2K0500.

Thanks.

Changes since V3:
- Addressed all review comments from v3
  - Change the changelog text to make it clearer (1/5);
  - Fix some minor bugs, such as formatting issues (2/5);
  - Fix some formatting issues, such as dropping quotes and checking with
    dt_binding_check (3/5);
  - Deep refactoring of code for clarity (4/5).
     Details: https://lore.kernel.org/all/Y4S2cnlAm3YYvZ8E@smile.fi.intel.com/

Thanks to all for their suggestions.

Changes since V2:
- Addressed all review comments from v2
  - Drop of_match_ptr() in i2c-gpio to avoid potential unused warnings
    (1/5);
  - Introduce i2c_gpio_get_props() function as the generic interface
    to get i2c-gpio props from DT or ACPI table (2/5);
  - Refact ls2x i2c code, similar to removing excessive goto tags (4/5).

Thanks to Andy and Mika for their suggestions.

Changes since V1:
- Remove the function of getting the static i2c bus number from ACPI "_UID";
- Fix build warning from kernel test robot.

Binbin Zhou (5):
  i2c: gpio: Fix potential unused warning for 'i2c_gpio_dt_ids'
  i2c: gpio: Add support on ACPI-based system
  dt-bindings: i2c: add bindings for Loongson LS2X I2C
  i2c: ls2x: Add driver for Loongson-2K/LS7A I2C controller
  LoongArch: Enable LS2X I2C in loongson3_defconfig

 .../bindings/i2c/loongson,ls2x-i2c.yaml       |  49 +++
 arch/loongarch/configs/loongson3_defconfig    |   1 +
 drivers/i2c/busses/Kconfig                    |  11 +
 drivers/i2c/busses/Makefile                   |   1 +
 drivers/i2c/busses/i2c-gpio.c                 |  30 +-
 drivers/i2c/busses/i2c-ls2x.c                 | 402 ++++++++++++++++++
 6 files changed, 482 insertions(+), 12 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/i2c/loongson,ls2x-i2c.yaml
 create mode 100644 drivers/i2c/busses/i2c-ls2x.c

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2.31.1