[PATCH 0/3] ASoC: fsl-asoc-card: Restructure to support deferrable card binding

[Chancel Liu]

From: Chancel Liu <chancel.liu@xxxxxxx>

The ASoC core has evolved over several kernel releases to support
deferrable card binding: when a component is not yet available,
devm_snd_soc_register_card() no longer propagates -EPROBE_DEFER back to
the machine driver. Instead the card is placed on an internal deferred
list and rebound automatically once the missing component registers.
As a result, registering a sound card no longer guarantees that all CPU
and codec components have already probed successfully.

This exposed two regressions in fsl-asoc-card:

1. The machine driver caches codec MCLK rate during probe(). On platforms
   where the MCLK is derived from the CPU DAI clock and its final rate is
   applied via assigned-clocks in the CPU DAI node, probing before the CPU
   DAI driver completes leaves fsl-asoc-card with a stale mclk_freq.

2. If a card defers due to a missing component, it queues the card onto
   the unbind_card_list and returns 0. The driver then proceeds to call
   simple_util_init_jack(). At this point, the snd_card pointer is NULL.

Patch 1 drops mclk management for nau8822 from this machine driver.

Patch 2 is a pure refactoring with no functional change. the large if/else
chain of of_device_is_compatible() calls in probe() is
replaced by a platform data table approach.

Patch 3 moves all component-dependent initialisation and jacks out of
probe() and into late_probe(), which is the correct place under the
deferrable binding model.

Chancel Liu (3):
  ASoC: fsl-asoc-card: Drop mclk management for nau8822
  ASoC: fsl-asoc-card: Move static compatible data to platform data
  ASoC: fsl-asoc-card: Move bound-component setup to late_probe

 sound/soc/fsl/fsl-asoc-card.c | 728 ++++++++++++++++++++++------------
 1 file changed, 465 insertions(+), 263 deletions(-)

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2.50.1