jesd204: core: Fix device lifecycle for proper register/unregister cycles #3100
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mhennerich
requested review from
CiprianRegus,
amiclaus,
btogorean,
buha,
chegbeli,
danmois,
dbogdan,
machschmitt,
nunojsa and
rbolboac
as code owners
…cles
The embedded struct device in jesd204_dev was not properly managed
across driver bind/unbind cycles, causing several issues:
1. Missing release function: The kernel requires every struct device to
have a release() function. Without one, put_device() triggers a
WARNING ("does not have a release() function, it is broken"). Add a
jesd204_dev_type with a no-op release callback, since the jdev
memory is managed separately by the jesd204 core.
2. Missing put_device() calls: device_del() must be paired with
put_device() to drop the reference taken by device_initialize().
Add the missing put_device() in both jesd204_dev_unregister() and
the err_device_del error path in jesd204_dev_register().
3. Stale device state on re-probe: After a driver unbinds,
jesd204_dev_unregister() must fully reset the embedded struct device
via memset so that a subsequent probe can safely call
device_initialize() + device_add() again with the same device name.
Without the memset, the kobject retains its initialized state,
triggering "tried to init an initialized object" warnings on
re-probe. Move the memset into the dev.parent conditional block
alongside device_del/put_device where it logically belongs.
4. Stale unregistered flag: When a driver probe fails after successful
jesd204_dev_register(), the devm cleanup sets jdev->unregistered to
true. On deferred probe retry, this flag was never cleared, which
would cause a subsequent unregister to skip cleanup. Reset the flag
at the start of jesd204_dev_register().
Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>
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PR Description
Further testing with overlays triggering deferred probe returns exhibited some more problems....
The embedded struct device in jesd204_dev was not properly managed across driver bind/unbind cycles, causing several issues:
Missing release function: The kernel requires every struct device to have a release() function. Without one, put_device() triggers a WARNING ("does not have a release() function, it is broken"). Add a jesd204_dev_type with a no-op release callback, since the jdev memory is managed separately by the jesd204 core.
Missing put_device() calls: device_del() must be paired with put_device() to drop the reference taken by device_initialize(). Add the missing put_device() in both jesd204_dev_unregister() and the err_device_del error path in jesd204_dev_register().
Stale device state on re-probe: After a driver unbinds, jesd204_dev_unregister() must fully reset the embedded struct device via memset so that a subsequent probe can safely call device_initialize() + device_add() again with the same device name. Without the memset, the kobject retains its initialized state, triggering "tried to init an initialized object" warnings on re-probe. Move the memset into the dev.parent conditional block alongside device_del/put_device where it logically belongs.
Stale unregistered flag: When a driver probe fails after successful jesd204_dev_register(), the devm cleanup sets jdev->unregistered to true. On deferred probe retry, this flag was never cleared, which would cause a subsequent unregister to skip cleanup. Reset the flag at the start of jesd204_dev_register().
PR Type