i2c: rtl9300: support for RTL9607C I2C controller

This patch series for the RTL9300 I2C driver adds i2c support for
RTL9607C SoC. They are somewhat different to the RTL9300 and
RTL9310 but not enough to warrant a new whole driver.

The patch series was split into patches that add/change something in the
driver to smooth out the RTL9607C support addition in the end and for
ease of review. Because of that, the patch 8 depends on all the prior
patches before it.

RTL9607C primarly uses the i2c controller for communication with laser
driver over on i2c interface 1 or 2.

I have successfully tested the byte read operations on my RTL9607C board
which has GN25L95 laser driver in OpenWrt.

This patch series now depends on the patch [1] from Jan Kantert.

[1] -
https://lore.kernel.org/all/20260227111134.2163701-1-jan-...

---
Changelog in v5
- reworded the commit message in Patch 5 to make it clear that the existing
  devices also have i2c master controller clocks.
- Link to v4: https://lore.kernel.org/linux-i2c/20260323071337.15410-1-...

Changelog in v4
- moved the patch 7 that changes bindings to be before patch 5 where clk
  is introduced in the driver.
- changed the "realtek,rtl9607-i2c" compatible to require the "clocks" to
  be specified and with it moved it out of "realtek,rtl9310-i2c" check to its
  own place for cleanliness (how it was originally in v1).
- Link to v3: https://lore.kernel.org/linux-i2c/20260322123411.32102-1-...

Changelog in v3
- Patch 7
  - reworded the commit message to better describe i2c clock.
  - make clocks property available for all compatibles.
  - change "realtek,rtl9607-i2c" compatible to be under the same if statement
    as "realtek,rtl9310-i2c" for "realtek,scl".
- Link to v2: https://lore.kernel.org/linux-i2c/20260319175753.32338-1-...

Changelog in v2
- rebased on top of the patch from Jan Kantert.
- Patch 7 (to my best understanding of Krzysztof's request):
 - added the "clocks: false" for compatibles that are not realtek,rtl9607-i2c.
- Link to v1: https://lore.kernel.org/linux-i2c/20260314082628.25206-1-...

Rustam Adilov (8):
  i2c: rtl9300: split data_reg into read and write reg
  i2c: rtl9300: introduce max length property to driver data
  i2c: rtl9300: introduce F_BUSY to the reg_fields struct
  i2c: rtl9300: introduce a property for 8 bit width reg address
  dt-bindings: i2c: realtek,rtl9301-i2c: extend for clocks and RTL9607C
    support
  i2c: rtl9300: introduce clk struct for upcoming rtl9607 support
  i2c: rtl9300: intoduce new function properties to driver data
  i2c: rtl9300: add RTL9607C i2c controller support

 .../bindings/i2c/realtek,rtl9301-i2c.yaml     |  15 ++
 drivers/i2c/busses/i2c-rtl9300.c              | 191 ++++++++++++++----
 2 files changed, 171 insertions(+), 35 deletions(-)

-- 
2.53.0