[PATCH v3 0/2] i2c: cadence: Add support for Axiado AX3000

[Swark Yang]

This patch series adds support for the Cadence I2C controller
integrated into the Axiado AX3000 SoC and enables SMBus Quick
command functionality.

The Axiado AX3000 utilizes the Cadence I2C IP core (version r1p14).
While it is largely compatible with the existing i2c-cadence
driver logic, the AX3000 hardware specifically supports SMBus Quick
commands. This feature is currently disabled by default in the
i2c-cadence driver (masked out from I2C_FUNC_SMBUS_EMUL).

To enable this functionality, this series introduces a new
platform-specific quirk (CDNS_I2C_ENABLE_SMBUS_QUICK) and 
uses driver match data for the "axiado,ax3000-i2c" compatible string.
This allows tools like 'i2cdetect' to properly scan the bus using
quick write commands.

The DT binding update follows the recommended fallback structure,
referencing the 'cdns,i2c-r1p14' fallback to ensure compatibility with
older kernels while allowing the new quirk to be enabled on AX3000.

Patch breakdown:

Patch 1: dt-bindings: i2c: cadence: Add Axiado AX3000
Patch 2: i2c: cadence: Add support for Axiado AX3000

These patches are expected to go via the I2C subsystem tree.

Feedback is welcome.

Signed-off-by: Swark Yang <syang at axiado.com>
---
Changes in v3:
- Addressed Sashiko AI bot report: Populated adapter quirks with I2C_AQ_NO_ZERO_LEN_READ to safely reject 0-length reads and prevent potential bus hangs.
- Note on AI review: The bot also reported a pre-existing UAF vulnerability triggered by 0-length reads. Since this v3 patch prevents the core from passing 0-length reads to the driver, this specific trigger path is mitigated for AX3000. Atomic transfer issues are left out of scope for this hardware enablement series.
- Renamed the quirk macro to CDNS_I2C_ENABLE_SMBUS_QUICK for consistency.
- Link to v2: https://lore.kernel.org/r/20260611-axiado-ax3000-cadence-i2c-support-v2-0-cfdad0534afa@axiado.com

Changes in v2:
- Collected Conor Dooley's Acked-by for Patch 1.
- No functional code changes (sent primarily as a RESEND to update status).
- Link to v1: https://lore.kernel.org/r/20260504-axiado-ax3000-cadence-i2c-support-v1-0-97ed2fdc0b7b@axiado.com

---
Swark Yang (2):
      dt-bindings: i2c: cadence: Add Axiado AX3000
      i2c: cadence: Add support for Axiado AX3000

 .../devicetree/bindings/i2c/cdns,i2c-r1p10.yaml    | 10 +++++++---
 drivers/i2c/busses/i2c-cadence.c                   | 23 ++++++++++++++++++++++
 2 files changed, 30 insertions(+), 3 deletions(-)
---
base-commit: 63804fed149a6750ffd28610c5c1c98cce6bd377
change-id: 20260111-axiado-ax3000-cadence-i2c-support-53ec117bb074

Best regards,
-- 
Swark Yang <syang at axiado.com>