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ASoC: cs35l56: Revert support for dual-ownership of ASP registers

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This patch reverts a series of commits that allowed for the ASP
registers to be owned by either the driver or the firmware. Nothing
currently depends on the functionality that is being reverted, so
it is safe to remove.

The commits being reverted are (last 3 are bugfixes to the first 2):
commit 72a77d7631
("ASoC: cs35l56: Fix to ensure ASP1 registers match cache")
commit 07f7d6e7a1
("ASoC: cs35l56: Fix for initializing ASP1 mixer registers")
commit 4703b014f2
("ASoC: cs35l56: fix reversed if statement in cs35l56_dspwait_asp1tx_put()")
commit c14f09f010
("ASoC: cs35l56: Fix deadlock in ASP1 mixer register initialization")
commit dfd2ffb373
("ASoC: cs35l56: Prevent overwriting firmware ASP config")

These reverts have been squashed into a single commit because there
would be no reason to revert only some of them (which would just
reintroduce bugs).

The changes introduced by the commits were well-intentioned but
somewhat misguided. ACPI does not provide any information about how
audio hardware is linked together, so that information has to be
hardcoded into drivers. On Windows the firmware is customized to
statically setup appropriate configuration of the audio links,
and the intent of the commits was to re-use this information if the
Linux host drivers aren't taking control of the ASP. This would
avoid having to hardcode the ASP config into the machine driver on
some systems.

However, this added complexity and race conditions into the driver.
It also complicates implementation of new code.

The only case where the ASP is used but the host is not taking
ownership is when CS35L56 is used in SoundWire mode with the ASP
as a reference audio interconnect. But even in that case it's not
necessarily required even if the firmware initialized it. Typically
it is used to avoid the host SDCA drivers having to be capable of
aggregating capture paths from multiple SoundWire peripherals. But
the SOF SoundWire support is capable of doing that aggregation.

Reverting all these commits significantly simplifies the driver.
Let's just use the normal Linux mechanisms of the machine driver and
ALSA controls to set things up instead of trying to use the firmware
to do use-case setup.

Signed-off-by: Richard Fitzgerald <rf@opensource.cirrus.com>
Link: https://patch.msgid.link/20240701104444.172556-2-rf@opensource.cirrus.com
Signed-off-by: Mark Brown <broonie@kernel.org>
This commit is contained in:
Richard Fitzgerald 2024-07-01 11:44:42 +01:00 • committed by Mark Brown
commit 5d7e328e20
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4 changed files with 43 additions and 273 deletions
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