[PATCH RESEND v5 0/2] riscv: spacemit: add i2c support to K1 SoC

Troy Mitchell
2025-03-03T05:33:39Z

Hi all,

This patch implements I2C driver for the SpacemiT K1 SoC,
providing basic support for I2C read/write communication which
compatible with standard I2C bus specifications.

In this version, the driver defaults to use fast-speed-mode and
interrupts for transmission, and does not support DMA, high-speed mode, or FIFO.

The docs of I2C can be found here, in chapter 16.1 I2C [1]

Link: https://developer.spacemit.com/documentation?token=Rn9Kw3iFHirAMgkIpTAcV2Arnkf#part5 [1]
---
I'm sorry for forgetting to CC Yixun Lan and SpacemiT, and for not syncing the Kconfig.
This re-send also corrects the warning mentioned in the CI test.
That's why I'm resending this.
---
Change in v5:
- Path #1:
- Add `clock-names` property
- Modify the clock property into two
- Path #2:
- Enable the APB clock
- Fix comment and code styles
- Fix typo and drop unnecessary description in Kconfig
- Prefix all macro definitions with SPACEMIT_
- Rename `spacemit_i2c_bus_reset` to `spacemit_i2c_conditionally_reset_bus`
- Remove all `unlikely` and `likely`
- Remove unused register and bit macros
- Remove the "err" field, as it only contains a subset of the status field
- Retrieve `clock-frequency` from the device tree instead of using a macro
- Use a local variable to track the current message
- Use `i2c->read` to represent read and write statuses instead of `i2c->dir`
Link to v4:
https://lore.kernel.org/all/20241125-k1-i2c-master-v4-0-0f3d5886336b@gmail.com/

Change in v4:
- Patch #1:
- Change the default value of clock-frequency from 100000 to
400000. This is to correspond to the driver's default value.
- Drop the minimum of clock-frequency
- Modify the description of clock-frequency
- Patch #2:
- Drop the `inline` qualifier from the `spacemit_i2c_xfer_core` function
- Drop the initialization of `ret` to 0 in `spacemit_i2c_xfer_core` function
- Drop useless wrap
Link to v3:
https://lore.kernel.org/all/20241112-k1-i2c-master-v3-0-5005b70dc208@gmail.com/

Change in v3:
- Patch #1:
- Change the maxItems of reg from 2 to 1 in properties
- Modify reg in dts example
- Changed the enum selection for clock-frequency to a range,
setting a minimum value of 1 and a maximum value of 3,300,000.
- Patch #2:
- Drop unused judgement in `spacemit_i2c_xfer_msg`
- Fix the dangling else warning in `spacemit_i2c_is_last_msg`
- Fix the error check for `i2c->base`
- Modify Kconfig dependencies
Link to v2:
https://lore.kernel.org/all/20241028053220.346283-1-TroyMitchell988@gmail.com/

Change in v2:
- Patch #1:
- Change the maxItems of reg from 1 to 2 in properties
- Change 'i2c' to 'I2C' in the commit message.
- Drop fifo-disable property
- Drop alias in dts example
- Move `unevaluatedProperties` after `required:` block
- Patch #2:
- Alphabetize Makefile and Kconfig
- Change `.remove_new` to `.remove` in `struct platform_driver`
- Change `dev_alert` to `dev_warn_ratelimited` in `spacemit_i2c_bus_reset`
- Change `spacemit_i2c_read/write_reg` to `read/writel`
- Change `spacemit_i2c_dt_match` to `spacemit_i2c_of_match`
- Clean up code flow
- Fix unnecessary line wraps
- Move `spacemit_i2c_handle_err` to a suitable location
- Modify Kconfig dependencies
- Use `PTR_ERR(i2c->base)` directly as the `dev_err_probe` parameter instead of
the intermediate variable
Link to v1:
https://lore.kernel.org/all/20241015075134.1449458-1-TroyMitchell988@gmail.com/

---
Troy Mitchell (2):
dt-bindings: i2c: spacemit: add support for K1 SoC
i2c: spacemit: add support for SpacemiT K1 SoC

.../devicetree/bindings/i2c/spacemit,k1-i2c.yaml | 59 ++
drivers/i2c/busses/Kconfig | 17 +
drivers/i2c/busses/Makefile | 1 +
drivers/i2c/busses/i2c-k1.c | 617 +++++++++++++++++++++
4 files changed, 694 insertions(+)
---
base-commit: 8e929cb546ee42c9a61d24fae60605e9e3192354
change-id: 20241031-k1-i2c-master-fe7f7b0dce93
prerequisite-change-id: 20240626-k1-01-basic-dt-1aa31eeebcd2:v5
prerequisite-patch-id: 47dcf6861f7d434d25855b379e6d7ef4ce369c9c
prerequisite-patch-id: 77787fe82911923aff15ccf565e8fa451538c3a6
prerequisite-patch-id: b0bdb1742d96c5738f05262c3b0059102761390b
prerequisite-patch-id: 3927d39d8d77e35d5bfe53d9950da574ff8f2054
prerequisite-patch-id: a98039136a4796252a6029e474f03906f2541643
prerequisite-patch-id: c95f6dc0547a2a63a76e3cba0cf5c623b212b4e6
prerequisite-patch-id: 66e750e438ee959ddc2a6f0650814a2d8c989139
prerequisite-patch-id: 29a0fd8c36c1a4340f0d0b68a4c34d2b8abfb1ab
prerequisite-patch-id: 0bdfff661c33c380d1cf00a6c68688e05f88c0b3
prerequisite-patch-id: 99f15718e0bfbb7ed1a96dfa19f35841b004dae9

Best regards,
--
Troy Mitchell <troymitchell988@gmail.com>