serial: amba-pl011: unprepare console clock on unregister

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pl011_console_setup() calls clk_prepare() on the UART clock, but the
console provides no matching teardown, so the clock is never unprepared
when the console is unregistered -- via the sysfs "console" attribute or
a driver unbind. Each re-registration prepares the clock again, leaking
one prepare reference per cycle.

Even where preparing the clock has no hardware effect, the stale
reference leaves the clock framework's prepare count unbalanced. For
providers with prepare/unprepare operations or runtime-PM integration,
it may also retain resources after the console is unregistered.

Add a console .exit() callback that clk_unprepare()s the clock,
balancing the clk_prepare() in pl011_console_setup().

Fixes: 4b4851c65d ("clk: amba-pl011: convert to clk_prepare()/clk_unprepare()")
Assisted-by: Claude:claude-fable-5
Signed-off-by: Karl Mehltretter <kmehltretter@gmail.com>
Link: https://patch.msgid.link/20260724213348.77418-2-kmehltretter@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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Karl Mehltretter 2026-07-24 23:33:47 +02:00 • committed by Greg Kroah-Hartman

parent 2339b2c6fb

commit 7f93da9d78

1 changed files with 10 additions and 0 deletions

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drivers/tty/serial/amba-pl011.c

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