Hi,
On Thu, May 21, 2026 at 11:43:37AM +0800, lianfeng.ouyang wrote:
> From: Lianfeng Ouyang <lianfeng.ouyang@starfivetech.com>
>
> The Synopsys DesignWare Core (DWC) I2C controller is a variant of the
> widely-used DesignWare I2C IP, with a distinct register layout and
> enhanced features such as SMBus Alert and programmable FIFO depths.
I wonder why they did shuffle the registers... :(
> This patch series introduces support for this controller as implemented
> on the StarFive JHB100 platform, which utilizes it for both master and
> slave operations (e.g., for MCTP over I2C).
>
> The series is structured as follows:
> 1. Adds the device tree binding document for the snps,dwc-i2c compatible.
> 2. Prepares the existing i2c-designware-core by exporting and making
> certain key functions overridable, allowing code reuse.
> 3. Introduces the new i2c-dwc-core driver, with separate modules for
> master and slave functionality, based on the 2023-07 revision of the
> Synopsys IP manual.
>
> Key differences from the Existing i2c-designware Driver
> 1. The DWC IP's offsets for all key registers are redefined. The driver
> maps to the correct addresses by overriding macros from the core
> header file in a new header (i2c-dwc-core.h).
Instead of this, can you provide a regmap that internally maps to these
shuffled registers?
> 2. The host and slave of DWC IP need to perform probe callbacks
> separately, so they cannot be directly set through i2c_dew_set_mode
> 3. Interrupts are cleared by writing to the corresponding bits in the
> INTR_CLRregister (write-1-to-clear).
> 4. The DWC controller's IC_ENABLEregister contains an additional
> TX_CMD_BLOCKcontrol bit. When enabling the controller, the driver must
> ensure this bit is cleared. When disabling, only the ENABLEbit is
> cleared, preserving other configurations.
>
> Lianfeng Ouyang (3):
> dt-bindings: i2c: snps,dwc-i2c: Add StarFive JHB100 bindings
> i2c: designware: Export symbols and add __weak for DWC I2C driver
> i2c: dwc: Add StarFive JHB100 I2C master/slave support
>
> .../devicetree/bindings/i2c/snps,dwc-i2c.yaml | 120 +++++
> MAINTAINERS | 7 +
> drivers/i2c/busses/Kconfig | 34 ++
> drivers/i2c/busses/Makefile | 3 +
> drivers/i2c/busses/i2c-designware-common.c | 57 ++-
> drivers/i2c/busses/i2c-designware-core.h | 25 +
> drivers/i2c/busses/i2c-designware-master.c | 14 +-
> drivers/i2c/busses/i2c-designware-platdrv.c | 6 +
> drivers/i2c/busses/i2c-designware-slave.c | 4 +-
> drivers/i2c/busses/i2c-dwc-core.h | 192 ++++++++
> drivers/i2c/busses/i2c-dwc-master.c | 441 ++++++++++++++++++
> drivers/i2c/busses/i2c-dwc-slave.c | 180 +++++++
Also the naming is confusing so if you need any glue code I recommend
calling it i2c-starfive-* instead.
> 12 files changed, 1068 insertions(+), 15 deletions(-)
> create mode 100644 Documentation/devicetree/bindings/i2c/snps,dwc-i2c.yaml
> create mode 100644 drivers/i2c/busses/i2c-dwc-core.h
> create mode 100644 drivers/i2c/busses/i2c-dwc-master.c
> create mode 100644 drivers/i2c/busses/i2c-dwc-slave.c
>
> --
> 2.43.0