2c5ad2d642
[ Upstream commit 79200d5851c8e7179f68a4a6f162d8f1bde4986f ]
In the previous commits that added CLK_OPS_PARENT_ENABLE, support for
this flag was only added to rate change operations (rate setting and
reparent) and disabling unused subtree. It was not added to the
clock gate related operations. Any hardware driver that needs it for
these operations will either see bogus results, or worse, hang.
This has been seen on MT8192 and MT8195, where the imp_ii2_* clk
drivers set this, but dumping debugfs clk_summary would cause it
to hang.
Prepare parent on prepare and enable parent on enable dependencies are
already handled automatically by the core as part of its sequencing.
Whether the case for "enable parent on prepare" should be supported by
this flag or not is not clear, and thus ignored for now.
This change solely fixes the handling of clk_core_is_enabled, i.e.
enabling the parent clock when reading the hardware state. Unfortunately
clk_core_is_enabled is called in a variety of places, sometimes with
the enable clock already held. To avoid deadlocking, the core will
ignore readouts and just return false if CLK_OPS_PARENT_ENABLE is set
but the parent isn't currently enabled.
Fixes: fc8726a2c021 ("clk: core: support clocks which requires parents enable (part 2)")
Fixes: a4b3518d146f ("clk: core: support clocks which requires parents enable (part 1)")
Signed-off-by: Chen-Yu Tsai <wenst@chromium.org>
Link: https://lore.kernel.org/r/20230103092330.494102-1-wenst@chromium.org
Tested-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.