[PATCH v4 0/4] i2c: designware: Improve device disable handling

[William A. Kennington III]

When the I2C controller attempts a new transaction while the target
controller is shutting down or restarting, it can lead to bus lockups
and system bootloops if the hardware enters an inconsistent state.

This patch series addresses this by ensuring that the internal state
machines are properly cleared when disabling the controller if target
activity is detected.

Additionally, it adds a shutdown hook that gracefully sets the target
disable bit before disabling the controller. This guarantees that any
incoming requests from the controller are immediately NACKed during
shutdown, preventing the bus from hanging.

Signed-off-by: William A. Kennington III <william@xxxxxxxxxxxxxxx>
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Changes in v4:
- Updated language to use inclusive terms
- Refactored some minor comment / code nits
- Link to v3: https://lore.kernel.org/r/20260504-dw-i2c-v3-0-57e56135d602@xxxxxxxxxxxxxxx
Changes in v3:
- Split the monolithic patch into 4 logical patches
- Reverted stray formatting change in the PCI driver's dw_i2c_driver struct.
Changes in v2:
- Fix description footers
- Fix emails

---
William A. Kennington III (4):
      i2c: designware: Introduce shutdown exported function
      i2c: designware: Convert PCI driver to use shutdown hook
      i2c: designware: Convert platform driver to use shutdown hook
      i2c: designware: Handle active target cleanly

 drivers/i2c/busses/i2c-designware-common.c  | 32 +++++++++++++++++++++++++++++
 drivers/i2c/busses/i2c-designware-core.h    |  1 +
 drivers/i2c/busses/i2c-designware-master.c  | 31 +++++++++++++++++-----------
 drivers/i2c/busses/i2c-designware-pcidrv.c  | 14 +++++++++++++
 drivers/i2c/busses/i2c-designware-platdrv.c | 14 +++++++++++++
 5 files changed, 80 insertions(+), 12 deletions(-)
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base-commit: 5862221fddede6bb15566ab3c1f23a3c353da5e1
change-id: 20260504-dw-i2c-d5a1b1a0036a

Best regards,
-- 
William A. Kennington III <william@xxxxxxxxxxxxxxx>