[PATCH v2 0/2] Add NXP PCA9641 I2C bus master arbiter support

[Shiv Prakash Gupta <shivprakash.gupta@nxp.com>]

This series adds device tree bindings and an I2C mux driver for the NXP
PCA9641 2-to-1 I2C bus master arbiter. The PCA9641 lets two upstream I2C
masters share a single downstream slave bus using a lock/grant protocol:
a master asserts LOCK_REQ, waits for LOCK_GRANT, sets BUS_CONNECT to open
the switch, performs its transactions, and then clears LOCK_REQ to release
the bus. The driver plugs into the i2c-mux core as an I2C_MUX_ARBITRATOR
and supports interrupt-assisted arbitration (via INT0/INT1 wired to a
GPIO) with a fallback to polling when no interrupt is configured.

Changes in v2:
- Binding: add Acked-by from Conor Dooley (no functional changes).
- Driver: drop IRQF_SHARED from the threaded IRQ request.
- Driver: clear the latched LOCK_REQ on every timeout path in
  select_chan() so a master that gives up does not block the peer.
- Driver: reorder probe interrupt setup - mask all sources and clear
  stale INT_STATUS before requesting the IRQ, then unmask LOCK_GRANT
  and BUS_LOST.
- Driver: re-mask interrupts if i2c_mux_add_adapter() fails.
- Driver: unregister the child adapter before masking interrupts in
  remove().
- Driver: use a named initializer for the i2c_device_id table.

Shiv Prakash Gupta (2):
  dt-bindings: i2c: Add NXP PCA9641 I2C bus master arbiter
  i2c: mux: Add NXP PCA9641 I2C bus master arbiter driver

 .../devicetree/bindings/i2c/nxp,pca9641.yaml  | 109 +++++
 MAINTAINERS                                   |   7 +
 drivers/i2c/muxes/Kconfig                     |  15 +
 drivers/i2c/muxes/Makefile                    |   1 +
 drivers/i2c/muxes/i2c-mux-pca9641.c           | 420 ++++++++++++++++++
 5 files changed, 552 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/i2c/nxp,pca9641.yaml
 create mode 100644 drivers/i2c/muxes/i2c-mux-pca9641.c

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2.34.1