[PATCH 0/4] ASoC: generic: Free jack GPIOs on card remove

[Chancel Liu <chancel.liu@oss.nxp.com>]

From: Chancel Liu <chancel.liu@nxp.com>

simple_util_init_jack() acquires a jack detection GPIO with
gpiod_get_optional() and passes it to snd_soc_jack_add_gpios(), which
also installs an IRQ handler, a PM notifier, a delayed work and a sysfs
export for it. None of simple-card, audio-graph-card or
audio-graph-card2 implements a card->remove() callback, so none of this
is ever released.

That goes unnoticed while the card is only torn down together with its
platform device, because the devres cleanup registered by
snd_soc_jack_add_gpios() is tied to that platform device. It becomes a
problem once the card alone is unregistered and registered again while
the platform device stays bound - for instance when a codec component is
unbound and bound again. card->probe() then runs a second time and
gpiod_get_optional() fails with -EBUSY, because the descriptor is still
held by the previous bind. The card is not registered again and audio
stays broken until the platform device itself is unbound.

Patch 1 adds the simple_util_remove_jack() helper, patches 2-4 wire it
up in the three generic card drivers.

Verified with audio-graph-card2 and a wm8962 codec using hp-det-gpios.
Before the series, the first

  echo 3-001a > /sys/bus/i2c/drivers/wm8962/unbind
  echo 3-001a > /sys/bus/i2c/drivers/wm8962/bind

leaves the GPIO line and IRQ claimed while the card is gone, and the
re-bind fails with

  ASoC error (-16): at graph_util_card_probe()
  ASoC error (-16): at snd_soc_card_probe() on wm8962-audio

after which the sound card never comes back. With the series applied,
both codec unbind/bind and platform unbind/bind cycles release the GPIO
and IRQ on unbind and fully restore the card.

Chancel Liu (4):
  ASoC: simple-card-utils: Add simple_util_remove_jack()
  ASoC: simple-card: Free jack GPIOs on card remove
  ASoC: audio-graph-card: Free jack GPIOs on card remove
  ASoC: audio-graph-card2: Free jack GPIOs on card remove

 include/sound/simple_card_utils.h     |  2 ++
 sound/soc/generic/audio-graph-card.c  |  1 +
 sound/soc/generic/audio-graph-card2.c |  1 +
 sound/soc/generic/simple-card-utils.c | 21 +++++++++++++++++++++
 sound/soc/generic/simple-card.c       | 11 +++++++++++
 5 files changed, 36 insertions(+)

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2.50.1