]> git.ipfire.org Git - thirdparty/kernel/stable.git/commit
Revert "clk: Respect CLK_OPS_PARENT_ENABLE during recalc"
authorStephen Boyd <sboyd@kernel.org>
Wed, 28 Jan 2026 19:01:34 +0000 (11:01 -0800)
committerStephen Boyd <sboyd@kernel.org>
Wed, 4 Feb 2026 05:28:18 +0000 (21:28 -0800)
commit448b50b5cf12b7df254cae1d7ba3746e1acfc683
treef6b683d40f9af1851b64da8145ed7b318bdbd61b
parentaa2ad19210a6a444111bce55e8b69579f29318fb
Revert "clk: Respect CLK_OPS_PARENT_ENABLE during recalc"

This reverts commit 669917676e93fca5ea3c66fc9539830312bec58e.
It's been shown to cause problems on i.MX and STM32 platforms
where the board doesn't boot. In one case, a clk with
CLK_IS_CRITICAL and CLK_OPS_PARENT_ENABLE is being registered
causing the parent to be enabled, the rate recalculated, and then
the parent is disabled causing the critical clk being registered
to stop clocking.

A fix for that would be to calculate the rate of the clk after
enabling the critical clk itself, but that wouldn't fix another
problem where a clk with CLK_OPS_PARENT_ENABLE is registered
before the parent is registered. In this case the hardware access
in the clk_ops::recalc_rate() function would fail if the parent
is disabled.

There are even more problems exposed by this patch because it
introduces logic that disables clks earlier in system boot than
has existed previously. Historically we've not disabled clks
until late init (clk_disable_unused) under the assumption that
clks have been registered enough to have a consistent view of the
clk tree. The clk_disable_unused logic doesn't work very well
though, leading to quite a few devices booting with
clk_ignore_unused on the kernel command line.

Long story short, disabling clks during clk registration is full
of pitfalls. Revert this commit until a proper solution can be
found.

Reported-by: Alexander Stein <alexander.stein@ew.tq-group.com>
Closes: https://lore.kernel.org/r/6239343.lOV4Wx5bFT@steina-w
Reported-by: Mark Brown <broonie@kernel.org>
Closes: https://lore.kernel.org/r/036da7ce-6487-4a6e-9b15-97c6d3bcdcec@sirena.org.uk
Cc: Nicolas Frattaroli <nicolas.frattaroli@collabora.com>
Cc: Brian Masney <bmasney@redhat.com>
Cc: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Cc: Chen-Yu Tsai <wenst@chromium.org>
Tested-by: Peng Fan <peng.fan@nxp.com>
Tested-by: Alexander Stein <alexander.stein@ew.tq-group.com>
Reviewed-by: Brian Masney <bmasney@redhat.com>
Tested-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>
drivers/clk/clk.c