On 25/09/26 15:11, Andy Shevchenko wrote:
On Fri, Sep 25, 2026 at 12:26:27PM +0530, Aniket Limaye wrote:
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
Still doesn't look good. The current register layout may be left as is. What
you need is translate it in the respective regmap callbacks in case we are
enumerated on the different IP. Also possible to have a different regmap
config for the different HW where you translate them only in one place.
Is it confusing to keep using existing offsets in regmap_read/write()
call sites for TDA54, and let the regmap silently handle the translation?
Given that we do *not* have any new registers in use on the tda54
version that were not there in the original one, I guess it works...
will send a v4 as per your suggestion.
Thanks,
Aniket
