[PATCH v3 0/3] i2c: designware: Add TI TDA54 I2C support

[Aniket Limaye]

Add new compatible and update driver to support Synopsys Advanced I2C
Controller (DWC_i2c [0]) present on TI TDA54 SoC. This is needed since
this controller differs from the existing designware i2c (DW_apb_i2c
[1]) in its register offsets and some register definitions.

The new compatible updates driver logic due to changes in register
definitions:

- The new register offsets are handled by first refactoring the driver
  to use a map of register IDs to their offsets.
- Similarly, also update the driver to use an updated CON-register
  bitfield definition.
- Interrupts are acknowledged by writing a bitmask to a single CLR_INTR
  register instead of reading N dedicated CLR_* registers;
  i2c_dw_ack_intr() picks the right method based on dev->flags.
- One HCNT/LCNT register pair is shared between standard and fast speed
  instead of having one pair each; i2c_dw_write_timings() writes
  whichever value set matches the configured speed.
- No COMP_PARAM_1 register, so FIFO depth and high-speed-mode support
  can't be autodetected: FIFO depth now comes from the required
  snps,tx-fifo-depth/snps,rx-fifo-depth DT properties, and the
  high-speed capability check is skipped.
- No defined CON.RESTART_EN bit; treat it as always set.
- TDA54 SoC does not support SMBus, so skip accesses to those registers.

[0]: DWC_i2c_reference.pdf
[1]: DW_apb_i2c_databook.pdf

Signed-off-by: Aniket Limaye <a-limaye@xxxxxx>
---
Changes in v3:
- [PATCH 2/3] Revert to special handling for the max_register in regmap
  for MODEL_AMD_NAVI_GPU instead of unconditionally including
  AMD_UCSI_INTR_REG in the legal regmap range. (sashiko)
- Link to v2: https://lore.kernel.org/r/20260925-tda54-upstream-i2c-v2-0-261785e58493@xxxxxx

Changes in v2:
- Rename compatible/flag: snps,dwc-i2c -> ti,tda54-i2c,
  MODEL_DWC_I2C -> MODEL_TI_TDA54.
- Move the Reg ID -> Offset mapping inside the regmap functions such
  that existing calls to reg_read/write are unaltered. This does change
  the reg_read()/reg_write() functions to take reg IDs as input rather
  than their physical offsets, which also requires updates to the
  xe_i2c.c driver to handle the same mapping.
- Remove i2c_dwc_has_smbus(); just skip the SMBUS_INTR_MASK write under
  MODEL_TI_TDA54.
- Link to v1: https://lore.kernel.org/r/20260919-tda54-upstream-i2c-v1-0-b0b9f77be18b@xxxxxx

---
Aniket Limaye (3):
      dt-bindings: i2c: dw: Add ti,tda54-i2c compatible
      i2c: designware: Support per-variant reg/bit offsets and intr handling
      i2c: designware: Add ti,tda54-i2c support

 .../bindings/i2c/snps,designware-i2c.yaml          |  33 ++++
 drivers/gpu/drm/xe/regs/xe_i2c_regs.h              |   3 +-
 drivers/i2c/busses/i2c-designware-amdisp.c         |   1 +
 drivers/i2c/busses/i2c-designware-common.c         | 193 ++++++++++++++++++---
 drivers/i2c/busses/i2c-designware-core.h           |  70 +++++++-
 drivers/i2c/busses/i2c-designware-master.c         |  78 +++++----
 drivers/i2c/busses/i2c-designware-pcidrv.c         |   2 +
 drivers/i2c/busses/i2c-designware-platdrv.c        |   3 +
 drivers/i2c/busses/i2c-designware-slave.c          |  26 +--
 include/linux/designware_i2c.h                     | 137 ++++++++++-----
 10 files changed, 432 insertions(+), 114 deletions(-)
---
base-commit: 587858367581b9c55c3690f4e63382ad622719d4
change-id: 20260919-tda54-upstream-i2c-d0c67f16b4fc

Best regards,
-- 
Aniket Limaye <a-limaye@xxxxxx>