linux-stable.git/include/linux/i3c, branch master

i3c: master: Use unsigned int for dev_nack_retry_count consistently

2026-06-16T21:19:19+00:00

Use unsigned int for dev_nack_retry_count across the core and
controller drivers to match the type of master->dev_nack_retry_count.

Update the sysfs store path to use kstrtouint() and adjust the
 ->set_dev_nack_retry() callback prototype and callers accordingly.

Signed-off-by: Adrian Hunter 
Reviewed-by: Frank Li 
Link: https://patch.msgid.link/20260616113752.196140-4-adrian.hunter@intel.com
Signed-off-by: Alexandre Belloni

i3c: master: Expose the APIs to support I3C hub

2026-06-15T23:27:25+00:00

Change the below internal static functions to APIs to allow new I3C hub
driver to use them

1) i3c_dev_enable_ibi_locked()
2) i3c_dev_disable_ibi_locked()
3) i3c_dev_request_ibi_locked()
4) i3c_dev_free_ibi_locked()
5) i3c_master_reattach_i3c_dev_locked()

Signed-off-by: Aman Kumar Pandey 
Signed-off-by: Lakshay Piplani 
Reviewed-by: Frank Li 
Link: https://patch.msgid.link/20260612111816.3688240-3-lakshay.piplani@nxp.com
Signed-off-by: Alexandre Belloni

i3c: master: Make i3c_master_add_i3c_dev_locked() return void

2026-06-14T19:49:11+00:00

The return value of i3c_master_add_i3c_dev_locked() is not used by any
caller, and callers are not in a position to recover from failures in
this path.

Change the function to return void.  Amend the kernel-doc accordingly,
fix some grammar and remove a stale paragraph.

Signed-off-by: Adrian Hunter 
Reviewed-by: Frank Li 
Link: https://patch.msgid.link/20260612080107.11606-6-adrian.hunter@intel.com
Signed-off-by: Alexandre Belloni

i3c: master: Export i3c_master_enec_disec_locked()

2026-06-14T19:40:10+00:00

The existing i3c_master_enec_locked() wrapper always treats a NACKed
ENEC CCC as a failure (M2 error).  However, broadcasting ENEC to enable
Hot-Join is legitimately useful even when no I3C devices are currently
present on the bus, in which case the broadcast will be NACKed and
should not be reported as an error.

The underlying helper i3c_master_enec_disec_locked() already accepts a
suppress_m2 flag that lets callers ignore such NACKs.  Expose it so that
a subsequent patch enabling Hot-Join events can issue ENEC with M2
suppression.

Signed-off-by: Adrian Hunter 
Reviewed-by: Frank Li 
Link: https://patch.msgid.link/20260608054312.10604-8-adrian.hunter@intel.com
Signed-off-by: Alexandre Belloni

i3c: master: Defer new-device registration out of DAA caller context

2026-06-14T19:40:10+00:00

Master drivers may invoke i3c_master_do_daa_ext() during resume to
re-run Dynamic Address Assignment.  As well as assigning addresses to
any newly arrived devices, this restores the dynamic address of devices
that lost it across system suspend, so it has to run as part of the
controller's resume path.

A side effect of i3c_master_do_daa_ext() today is that it also
registers any newly discovered I3C devices with the driver model
inline, via i3c_master_register_new_i3c_devs().  Doing that from the
resume path is problematic: a hot-join-capable device may join the bus
during this same DAA, and registering it immediately would push driver
model work (probing, sysfs, etc.) into the controller's resume context,
where the rest of the system is not yet fully resumed and the
controller driver is still partway through its own resume sequence.

Decouple discovery from registration: add a reg_work work item to
struct i3c_master_controller and have i3c_master_do_daa_ext() queue it
on master->wq (the freezable workqueue) instead of calling
i3c_master_register_new_i3c_devs() directly.  The worker performs the
registration only when the controller is not shutting_down, and is
cancelled alongside hj_work in i3c_master_shutdown().  Because wq is
freezable, any newly observed devices end up being registered after
the system has finished resuming.

i3c_master_register() also routes its initial post-bus-init registration
through reg_work, using flush_work() to keep probe-time behavior
synchronous.  This keeps a single registration code path and ensures the
worker is the only writer of desc->dev.

Fixes: 3a379bbcea0af ("i3c: Add core I3C infrastructure")
Signed-off-by: Adrian Hunter 
Reviewed-by: Frank Li 
Link: https://patch.msgid.link/20260608054312.10604-7-adrian.hunter@intel.com
Signed-off-by: Alexandre Belloni

i3c: master: Ensure Hot-Join operations are stopped on shutdown

2026-06-14T19:40:10+00:00

System shutdown invokes each device's bus shutdown callback to quiesce
hardware, but the I3C bus type does not currently implement one.  As a
result, on shutdown the controller's Hot-Join work and any in-flight
i3c_master_do_daa() can keep running (or be newly triggered) while the
rest of the system is being torn down.

A similar window exists at i3c_master_unregister() time: cancel_work_sync()
on hj_work prevents queued work from completing, but does not stop a
fresh Hot-Join IBI from re-queueing the worker, nor a concurrent sysfs
writer from toggling Hot-Join via i3c_set_hotjoin().

Introduce a single "shutting down" gate in the I3C core, set under the
bus maintenance lock so it is observed by any in-progress DAA path
before pending work is cancelled.  Install an i3c_bus_type shutdown
callback that engages this gate for master devices during system
shutdown, and use the same gate in i3c_master_unregister() so both
paths get identical guarantees.

Once the gate is engaged, the Hot-Join worker, i3c_master_do_daa_ext()
and i3c_set_hotjoin() all bail out cleanly, so Hot-Join IBIs that race
with shutdown become no-ops, direct DAA callers see -ENODEV, and sysfs
writers can no longer re-enable Hot-Join through ops->enable_hotjoin()
while the controller is going away.

No functional change for the steady-state runtime path; the new checks
only take effect once the controller has been marked as shutting down.

Note, this patch depends on patch "i3c: master: Consolidate Hot-Join DAA
work in the core".

Fixes: 3a379bbcea0af ("i3c: Add core I3C infrastructure")
Signed-off-by: Adrian Hunter 
Reviewed-by: Frank Li 
Link: https://patch.msgid.link/20260608054312.10604-5-adrian.hunter@intel.com
Signed-off-by: Alexandre Belloni

i3c: master: Consolidate Hot-Join DAA work in the core

2026-06-14T19:40:10+00:00

Three master drivers (dw-i3c-master, i3c-master-cdns, svc-i3c-master)
each carry an essentially identical Hot-Join handler: a struct
work_struct embedded in their private state, a work function that just
calls i3c_master_do_daa() on the embedded i3c_master_controller, plus
matching INIT_WORK()/cancel_work_sync() boilerplate in probe/remove (and
shutdown for dw-i3c). The IBI/ISR paths then queue that work onto
master->wq, which already lives in the core.

Move this pattern into the I3C core:

 - Add struct work_struct hj_work to struct i3c_master_controller and
   initialise it in i3c_master_register() with a core-provided handler
   i3c_master_hj_work_fn() that performs i3c_master_do_daa().
 - Cancel the work in i3c_master_unregister() so all controllers get
   correct teardown ordering against the workqueue for free.
 - Export i3c_master_queue_hotjoin() as the single entry point drivers
   call from their Hot-Join IBI handler.

Convert the three existing users to the new API: drop their private
hj_work fields, work functions, INIT_WORK() and cancel_work_sync()
calls, and replace the queue_work(master->wq, &drv->hj_work) call sites
with i3c_master_queue_hotjoin(&drv->base). The dw-i3c shutdown path
still needs to flush pending Hot-Join work before tearing down the
hardware, so it is updated to cancel master->base.hj_work directly.

No functional change intended: the work is still queued on the same
master->wq, runs the same i3c_master_do_daa(), and is cancelled at
controller teardown.  Future Hot-Join improvements now only need to
be made in one place.

Signed-off-by: Adrian Hunter 
Reviewed-by: Frank Li 
Link: https://patch.msgid.link/20260608054312.10604-4-adrian.hunter@intel.com
Signed-off-by: Alexandre Belloni

i3c: master: Make hot-join workqueue freezable to block hot-join during suspend

2026-06-14T19:40:10+00:00

The I3C master workqueue (master->wq) is used to defer work that needs
thread context and the bus maintenance lock, most notably Hot Join
processing (which calls i3c_master_do_daa() to assign dynamic addresses
to newly joined devices).

Currently the workqueue keeps running across system suspend, which can
race with the suspend path:

 - do_daa() may execute after the controller has been suspended,
   issuing bus transactions on a powered-down or otherwise unusable
   controller.
 - New I3C devices can be enumerated and added to the bus mid-suspend,
   registering driver model objects at a point where the I3C subsystem
   and its consumers are not prepared to handle them.

Mark the workqueue WQ_FREEZABLE so its workers are frozen for the
duration of system suspend/hibernate and resumed afterwards. This
naturally defers any pending or newly queued Hot Join work until the
system (and the controller) is fully resumed, closing both races
without adding explicit suspend/resume synchronization in the master
drivers.

Update the kerneldoc for struct i3c_master_controller::wq to reflect
that the workqueue is freezable.

Fixes: 3a379bbcea0af ("i3c: Add core I3C infrastructure")
Signed-off-by: Adrian Hunter 
Reviewed-by: Frank Li 
Link: https://patch.msgid.link/20260608054312.10604-2-adrian.hunter@intel.com
Signed-off-by: Alexandre Belloni

i3c: master: Add i3c_master_do_daa_ext() for post-hibernation address recovery

2026-01-30T23:02:24+00:00

After system hibernation, I3C Dynamic Addresses may be reassigned at boot
and no longer match the values recorded before suspend. Introduce
i3c_master_do_daa_ext() to handle this situation.

The restore procedure is straightforward: issue a Reset Dynamic Address
Assignment (RSTDAA), then run the standard DAA sequence. The existing DAA
logic already supports detecting and updating devices whose dynamic
addresses differ from previously known values.

Refactor the DAA path by introducing a shared helper used by both the
normal i3c_master_do_daa() path and the new extended restore function,
and correct the kernel-doc in the process.

Export i3c_master_do_daa_ext() so that master drivers can invoke it from
their PM restore callbacks.

Signed-off-by: Adrian Hunter 
Reviewed-by: Frank Li 
Link: https://patch.msgid.link/20260123063325.8210-2-adrian.hunter@intel.com
Signed-off-by: Alexandre Belloni

i3c: master: Introduce optional Runtime PM support

2026-01-14T16:21:10+00:00

Master drivers currently manage Runtime PM individually, but all require
runtime resume for bus operations.  This can be centralized in common code.

Add optional Runtime PM support to ensure the parent device is runtime
resumed before bus operations and auto-suspended afterward.

Notably, do not call ->bus_cleanup() if runtime resume fails.  Master
drivers that opt-in to core runtime PM support must take that into account.

Also provide an option to allow IBIs and hot-joins while runtime suspended.

Signed-off-by: Adrian Hunter 
Reviewed-by: Frank Li 
Link: https://patch.msgid.link/20260113072702.16268-20-adrian.hunter@intel.com
Signed-off-by: Alexandre Belloni