[PATCH v2] clk: scu/imx8qxp: do not register driver in probe()

[Abel Vesa]

On 26-02-23 21:21:29, Danilo Krummrich wrote:
> On Fri Feb 13, 2026 at 12:58 AM CET, Danilo Krummrich wrote:
> > imx_clk_scu_init() registers the imx_clk_scu_driver while commonly being
> > called from IMX driver's probe() callbacks.
> >
> > However, it neither makes sense to register drivers from probe()
> > callbacks of other drivers, nor does the driver core allow registering
> > drivers with a device lock already being held.
> >
> > The latter was revealed by commit dc23806a7c47 ("driver core: enforce
> > device_lock for driver_match_device()") leading to a deadlock condition
> > described in [1].
> >
> > Besides that, nothing seems to unregister the imx_clk_scu_driver once
> > the corresponding driver module is unloaded, which leaves the
> > driver-core with a dangling pointer.
> >
> > Also, if there are multiple matching devices for the imx8qxp_clk_driver,
> > imx8qxp_clk_probe() calls imx_clk_scu_init() multiple times.  However,
> > any subsequent call after the first one will fail, since the driver-core
> > does not allow to register the same struct platform_driver multiple
> > times.
> >
> > Hence, register the imx_clk_scu_driver from module_init() and unregister
> > it in module_exit().
> >
> > Note that we first register the imx8qxp_clk_driver and then call
> > imx_clk_scu_module_init() to avoid having to call
> > imx_clk_scu_module_exit() in the unwind path of imx8qxp_clk_init().
> >
> > Fixes: dc23806a7c47 ("driver core: enforce device_lock for driver_match_device()")
> > Fixes: 220175cd3979 ("clk: imx: scu: fix build break when compiled as modules")
> > Reported-by: Alexander Stein <alexander.stein at ew.tq-group.com>
> > Closes: https://lore.kernel.org/lkml/13955113.uLZWGnKmhe@steina-w/
> > Tested-by: Alexander Stein <alexander.stein at ew.tq-group.com> # TQMa8x/MBa8x
> > Link: https://lore.kernel.org/lkml/DFU7CEPUSG9A.1KKGVW4HIPMSH@kernel.org/ [1]
> > Signed-off-by: Danilo Krummrich <dakr at kernel.org>

Acked-by: Abel Vesa <abelvesa at kernel.org>

> 
> Just a quick reminder now that -rc1 is out; I think it would be good if this
> could go to Linus for -rc2.
> 
> (Just in case it helps, please let me know if you want me to take it through the
> driver-core tree for this purpose.)

Sure. Go ahead.

Thanks!