Re: [PATCH v17 0/8] Add support for NXP P3H2x4x I3C hub driver

[Frank Li]

On Wed, Sep 02, 2026 at 03:59:21PM +0530, Lakshay Piplani wrote:
> This series adds support for the NXP P3H2x4x family of multi-port I3C
> hub devices, including their on-die regulators and downstream I3C/SMBus
> target ports

can you rebase to v7.3-rc1?

https://sashiko.dev/#/patchset/20260902102929.2268307-1-lakshay.piplani%40nxp.com

sashkio failure apply

Frank
>
> The series introduces:
> - Core I3C master enhancements required for hub support
> - Generic I3C hub framework
> - MFD driver with regulator and I3C hub child drivers for the P3H2x4x I3C hub
>
> The dependency order within the series is:
>
> - Patches 1 and 2 provide the I3C core helpers required by the generic
>   I3C hub framework
> - Patch 3 provides the P3H2x4x Device Tree binding
> - Patch 4 provides the MFD parent required by both the regulator and
>   P3H2x4x I3C hub child drivers
> - Patch 5 provides the regulator child driver and depends on patch 4
> - Patch 6 provides the generic I3C hub framework and depends on the
>   I3C core changes in patches 1 and 2
> - Patch 7 provides the P3H2x4x I3C hub child driver and depends on
>   patches 4 and 6
> - Patch 8 extends the P3H2x4x hub driver with SMBus slave mode support
>   and depends on patch 7
>
> Changes in v17:
> - Document the calling context of i3c_dev_recycle_ibi_slot_controller():
>   it runs in workqueue context without the bus lock held, while the
>   controller owns and synchronizes its IBI pool
> - Retain the request_ibi capability check to preserve the pre-series
>   behaviour for regular I3C devices
> - Explain in the binding description that all variants share the same register
>   interface, software reads the target-port count from DEV_CAPAB, and
>   the x0/x1 variants differ only in power-up defaults that the driver
>   overrides
> - Remove the fixed post-enable delay; regulator settling is now handled
>   by the regulator core
> - Add .enable_time = 5000 through P3H2X4X_LDO_ENABLE_TIME_US to all four
>   LDO descriptors, so the regulator core applies the post-enable
>   settling delay
> - Move the lockdep-only routing-lock class assignment into a dedicated
>   helper, leaving hub context initialization unconditional when
>   CONFIG_LOCKDEP is disabled
> - Document that hub_dev must already be registered and remove the
>   WARN_ON_ONCE checks for its descriptor and parent controller
> - Export i3c_hub_master_ops as a const object and reference it directly
>   instead of returning it through an accessor
> - Document that downstream ports share the parent controller's dynamic
>   address domain and that independent per-port DAA domains are not
>   provided
> - Document that a broadcast CCC on a virtual bus reaches the parent bus
>   and devices behind other connected ports; directed CCCs must be used
>   for per-device scope
> - Document that fixed-DT address reservations remain allocated for the
>   lifetime of the parent bus, are reused across driver reprobes, and
>   that downstream hot-join support would also require reserving static
>   addresses
> - Use a named initializer for the platform_device_id table
> - Document why I3C target ports are connected once and left connected,
>   making their per-operation enable and disable callbacks no-ops
> - Reference the exported i3c_hub_master_ops object directly
> - Link to v16: https://lore.kernel.org/linux-i3c/20260826103819.1614843-1-lakshay.piplani@xxxxxxx/T/#u
>
> Changes in v16:
> - Rename the controller-only helpers with a "_locked" suffix to
>   make the parent-bus locking contract explicit, route IBI slot recycling
>   through the controller helper, and destroy the generic IBI workqueue when
>   request_ibi() fails
> - Fix a lockdep "recursive locking" false positive on the hub forwarding path
>   by giving the virtual bus lock and hub routing mutex per-nesting-depth
>   lockdep classes
> - Fix parent-bus dynamic-address reservation to reserve by assigned-address
>   and only when the slot is free, avoiding ENTDAA collisions
> - Make downstream reattach atomic against asynchronous IBI and reject it while
>   an IBI is live; detach IBI-lifetime invariant documented and checked with
>   WARN_ON_ONCE; underlying core IBI teardown fix deferred (known I3C-core
>   limitation)
> - Tighten the target-port reg schema (explicit minimum 0, maximum 7, and
>   maximum 3 for four-port variants)
> - Do not ignore regulator-enable failures during hub configuration
> - Widen the SMBus poll deadline to the datasheet SDA-stuck/SCL-low recovery
>   window and use DMA-safe buffers for controller-agent and SMBus-agent
>   transfers over I3C
> - Advertise I2C_FUNC_SLAVE only when CONFIG_I2C_SLAVE is enabled, reject slave
>   registration unless the upstream I3C device and IBI path are available, and
>   always clear the software slave state on unregister
> - Validate the SMBus-agent IBI payload length and bound the target-port loop
>   by num_target_ports before dispatching receive events
> - Link to v15: https://lore.kernel.org/linux-i3c/20260817103844.2142802-1-lakshay.piplani@xxxxxxx/T/#u
>
> Changes in v15:
> - Replace the direct attach and detach APIs with controller-only helpers
>   that do not modify address-slot state, device lists or generic IBI
>   lifecycle state
> - Add controller-only helpers for device attach, reattach and detach,
>   and for requesting, freeing, enabling, disabling and recycling IBI
>   resources
> - Rework the generic hub architecture to keep downstream logical device
>   descriptors associated with their virtual controllers
> - Add a permanent parent-facing descriptor for each downstream device
>   and use it for operations handled by the physical parent controller
> - Remove temporary descriptor reparenting and temporary hub dynamic
>   address replacement from downstream transfer paths
> - Forward downstream private transfers and the complete IBI lifecycle,
>   including IBI slot recycling, through the parent-facing descriptor
>   with appropriate parent-bus locking
> - Add binding and MFD support for the P3H2440, P3H2441, P3H2840 and
>   P3H2841 variants
> - Fix the target-port reg schema and update the binding examples to use
>   SMBus target-port nodes
> - Read the device capability register to determine whether the device
>   provides four or eight target ports
> - Configure and register only the target ports implemented by the
>   selected device variant
> - Preserve the MFD parent's driver data and store the hub context in the
>   shared MFD structure for use by IBI callbacks
> - Validate target-port types and indices while ignoring non-target-port
>   children, such as the regulators node, during Device Tree parsing
> - Correct the SMBus transfer timeout calculation for 400 kHz operation
> - Use I2C adapter quirks to enforce the maximum supported read and write
>   payload lengths
> - Publish callback-visible SMBus adapter state before adapter
>   registration and roll it back if registration fails
> - Rework SMBus slave registration and unregistration to use the shared
>   protected-register lock and update software state only after the
>   corresponding hardware operation succeeds
> - Update the MFD source description to identify the device as an NXP
>   P3H2x4x multi-port I3C hub instead of referring to it as an "MFD
>   device driver"
> - Link to v14: https://lore.kernel.org/linux-i3c/20260714092053.2461482-1-lakshay.piplani@xxxxxxx/T/#u
>
> Changes in v14:
> - Add i3c_master_register_fwnode() for virtual I3C masters and use it instead of temporarily changing
>   parent dev->of_node
> - Add runtime PM handling in i3c_master_send_ccc_cmd()
> - Export i3c_bus_maintenance_lock()/unlock() and use them in hub paths
> - Fix IBI request/free cleanup to handle forwarded callbacks that clear dev->ibi, and destroy the
>   allocated IBI workqueue on request failure
> - Add a shared MFD protected_reg_lock and use it for protected register accesses across P3H2X4X
>   child drivers
> - Rework regulator protected-register handling to restore the original protection state after
>   each operation
> - Serialize hub route selection around DAA, CCC, private transfer and IBI paths
> - Hold the parent maintenance lock across temporary hub address reattach, transfer and address
>   restore
> - Fix SMBus polling interval calculation
> - Clean up already registered SMBus adapters on adapter allocation or registration failure
> - Fix SMBus slave receive status handling by clearing receive flags on error paths, using FIELD_GET()
>   and explicitly clearing overflow status
> - Link to v13: https://lore.kernel.org/linux-i3c/20260701065755.2067793-1-lakshay.piplani@xxxxxxx/T/#u
>
> Changes in v13:
> - Fix I3C master address management in direct attach/detach paths by using i3c_master_get_i3c_addrs()
>   adding rollback on failure, skipping master self attach/detach, and properly releasing addresses to
>   avoid stale state and use-after-free issues.
> - Export and document address slot helper APIs for I3C hub support.
> - Reserve parent bus address slots for downstream devices with identical static and assigned addresses
>   by parsing target-port DT nodes prior to virtual controller registration, preventing DAA conflicts.
> - Keep broadcast RSTDAA blocked with added documentation, and clarify intentional no-op callbacks
>   and pending TODOs (e.g., IBI slot recycle).
> - Rework SMBus transaction handling to use polling instead of fixed delays
>   avoiding premature reads and data corruption.
> - Fix DT handling issues by preventing duplicate target-port node leaks and restoring dev->of_node
>   after temporary modification.
> - Improve resource management using devm-based cleanup for DT nodes, IBI setup, adapter unregister
>   and register relock paths.
> - Make IBI setup optional and robust to avoid probe failures on unsupported platforms, with proper cleanup.
> - Fix SMBus slave receive path by improving buffer handling, event delivery, and handling of unregistered ports.
> - Strengthen concurrency handling with proper locking around shared state.
> - Link to v12: https://lore.kernel.org/linux-i3c/20260617110355.1591844-1-lakshay.piplani@xxxxxxx/T/#u
>
> Changes in v12:
> - Rebased on i3c/next
> - Dropped patches 1/9 and 2/9 from v11 as they are already applied
> - Add address check in i3c_master_direct_detach_i3c_dev_locked() to skip
>   detach for unaddressed devices
> - Drop redundant depends on I3C from config I3C_HUB
> - Return -EOPNOTSUPP for unsupported I2C transfers in the generic hub ops
> - Correct default pull-up and drive-strength values
> - Add devm cleanup for the IBI request/enable path
> - Remove dead code and simplify cleanup by relying on devm-managed resources
> - Fix SMBus slave client NULL handling and unregister cleanup
> - Link to v11: https://lore.kernel.org/linux-i3c/20260612111816.3688240-1-lakshay.piplani@xxxxxxx/T/#u
>
> Changes in v11:
> - Convert i3c_master_supports_ccc_cmd() to return bool and align
>   semantics with CCC support checks used by the I3C core
> - Use MFD_CELL_NAME() for child device registration
> - Rename driver names to follow subsystem conventions:
>      - Use '-' instead of '_' in driver names
>      - Drop the "_drv" suffix from driver names
> - Fix virtual hub address reattach handling and parent bus locking
> - Fix IBI request and cleanup error paths
> - Improve SMBus slave mode payload validation and parsing
> - Link to v10: https://lore.kernel.org/linux-i3c/20260525064209.2263045-1-lakshay.piplani@xxxxxxx/T/#u
>
> Changes in v10:
> - Rename i3c_master_reattach_i3c_dev() to *_locked to reflect required
>   bus locking
> - Rename i3c_master_direct_attach_i3c_dev() and i3c_master_direct_detach_i3c_dev()
>   to *_locked, as these APIs must be called with the bus lock held for write
> - Drop redundant is_p3h2x4x_in_i3c flag from p3h2840.h
> - Remove unnecessary ibi_lock handling in request/enable/disable/free
>   IBI APIs
> - Remove redundant parent pointer from struct i3c_hub and derive upstream
>   master from hub_dev
> - Split SMBus target/slave mode support, including IBI and MCTP receive handling,
>   into a separate patch
> - Link to v9: https://lore.kernel.org/linux-i3c/20260420105222.1562243-1-lakshay.piplani@xxxxxxx/T/#u
>
> Changes in v9:
> - Renamed macros to follow consistent uppercase naming conventions
> - Made REGMAP selects in the P3H2X4X MFD Kconfig conditional, to avoid I3C/I2C dependency issues
> - Referenced i3c.yaml and i2c-controller.yaml for child bus nodes
> - Dropped unnecessary #address-cells and #size-cells from child nodes
> - Added CONFIG_I2C_SLAVE guards where necessary to avoid build errors when I2C slave support is disabled
> - Link to v8: https://lore.kernel.org/linux-i3c/20260323062737.886728-1-lakshay.piplani@xxxxxxx/T/#u
>
> Changes in v8:
> - Add compatible in i3c example
> - Link to v7: https://lore.kernel.org/linux-i3c/20260319112441.3888957-1-lakshay.piplani@xxxxxxx/T/#u
>
> Changes in v7:
> - Fix kernel-doc warnings across I3C core and hub code
> - Rework DT binding schema and examples to pass dt_binding_check
> - Update MFD Kconfig to use I3C_OR_I2C
> - Convert CONFIG_I3C_HUB to tristate
> - Remove unnecessary CONFIG_I2C_SLAVE guards
> - Replace custom helpers with find_closest()
> - Use devm_regulator_get_enable_optional()
> - Link to v6: https://lore.kernel.org/linux-i3c/64c5070c-aa9e-427a-933e-91e168f0510c@xxxxxxxxxx/T/#u
>
> Changes in v6:
> - Update DT binding with vendor-prefixed properties
> - Add generic I3C hub support
> - Remove generic code from P3H2x4x driver
> - Link to v5: https://lore.kernel.org/linux-i3c/20260206120121.856471-1-aman.kumarpandey@xxxxxxx/T/#u
>
> Changes in v5:
> - Update supply naming and descriptions
> - Improve MFD Kconfig/Makefile ordering
> - Link to v4: https://lore.kernel.org/linux-i3c/20260113114529.1692213-2-aman.kumarpandey@xxxxxxx/T/#u
>
> Changes in v4:
> - Split driver into MFD, regulator and I3C hub parts
> - Update I3C master for hub support
> - Fix DT binding issues
> - Link to v3: https://lore.kernel.org/linux-i3c/20250811-bittern-of-abstract-prestige-aaeda9@kuoka/T/#u
>
> Changes in v3:
> - Add MFD support for hub and regulators
> - Add regulator integration
> - Link to v2: https://lore.kernel.org/linux-i3c/17145d2f-5d07-4939-8381-74e27cde303c@xxxxxxxxxx/T/#u
>
> Changes in v2:
> - Fix DT binding warnings
> - Refine DT parsing logic
> - Link to v1: https://lore.kernel.org/linux-i3c/822d6dca-b2c6-4439-ade5-219620ebc435@xxxxxxxxxx/T/#u
>
> Aman Kumar Pandey (5):
>   i3c: master: Add APIs for I3C hub support
>   dt-bindings: i3c: Add NXP P3H2x4x i3c-hub support
>   mfd: p3h2x4x: Add driver for NXP P3H2x4x i3c hub and on-die regulator
>   regulator: p3h2x4x: Add driver for on-die regulators in NXP P3H2x4x
>     i3c hub
>   i3c: hub: p3h2x4x: Add support for NXP P3H2x4x I3C hub functionality
>
> Lakshay Piplani (3):
>   i3c: master: Add controller-only device operation helpers
>   i3c: hub: Add support for the I3C interface in the I3C hub
>   i3c: hub: p3h2x4x: Add SMBus slave mode support
>
>  .../devicetree/bindings/i3c/nxp,p3h2840.yaml  | 328 +++++++
>  MAINTAINERS                                   |  15 +
>  drivers/i3c/Kconfig                           |  15 +
>  drivers/i3c/Makefile                          |   2 +
>  drivers/i3c/hub.c                             | 832 ++++++++++++++++++
>  drivers/i3c/hub/Kconfig                       |  11 +
>  drivers/i3c/hub/Makefile                      |   4 +
>  drivers/i3c/hub/p3h2840_i3c_hub.h             | 362 ++++++++
>  drivers/i3c/hub/p3h2840_i3c_hub_common.c      | 413 +++++++++
>  drivers/i3c/hub/p3h2840_i3c_hub_i3c.c         | 178 ++++
>  drivers/i3c/hub/p3h2840_i3c_hub_smbus.c       | 651 ++++++++++++++
>  drivers/i3c/internals.h                       |  14 +
>  drivers/i3c/master.c                          | 394 +++++++--
>  drivers/mfd/Kconfig                           |  13 +
>  drivers/mfd/Makefile                          |   1 +
>  drivers/mfd/p3h2840.c                         | 167 ++++
>  drivers/regulator/Kconfig                     |  10 +
>  drivers/regulator/Makefile                    |   1 +
>  drivers/regulator/p3h2840_i3c_hub_regulator.c | 289 ++++++
>  include/linux/i3c/device.h                    |   2 +
>  include/linux/i3c/hub.h                       |  92 ++
>  include/linux/i3c/master.h                    |  17 +
>  include/linux/mfd/p3h2840.h                   |  41 +
>  23 files changed, 3801 insertions(+), 51 deletions(-)
>  create mode 100644 Documentation/devicetree/bindings/i3c/nxp,p3h2840.yaml
>  create mode 100644 drivers/i3c/hub.c
>  create mode 100644 drivers/i3c/hub/Kconfig
>  create mode 100644 drivers/i3c/hub/Makefile
>  create mode 100644 drivers/i3c/hub/p3h2840_i3c_hub.h
>  create mode 100644 drivers/i3c/hub/p3h2840_i3c_hub_common.c
>  create mode 100644 drivers/i3c/hub/p3h2840_i3c_hub_i3c.c
>  create mode 100644 drivers/i3c/hub/p3h2840_i3c_hub_smbus.c
>  create mode 100644 drivers/mfd/p3h2840.c
>  create mode 100644 drivers/regulator/p3h2840_i3c_hub_regulator.c
>  create mode 100644 include/linux/i3c/hub.h
>  create mode 100644 include/linux/mfd/p3h2840.h
>
> --
> 2.25.1
>