[PATCH 0/2] ASoC: codecs: ak4619: Add PDN pin handling

[Alexander Koch <mail@alexanderkoch.net>]

The AK4619 datasheet describes the functionality of the power down (PDN)
pin as follows:

  The AK4619 should be powered up when the PDN pin = "L". The PDN pin
  should be set "H" after all power supplies have ramped up.
  At that point, the reference voltage generator block (REFBLK) and LDO
  (AVDRV) circuit are powered up and the control registers are
  initialized. Control register settings should be no less than 10ms
  after PDN pin = "H". [1]

The current implementation of the driver does not operate the PDN pin
in any way, it seems to rely on external control of the pin.

Improve this by adding a device tree binding to enable the driver to
set the pin 'high' during probe. Make it optional to keep the behaviour
for existing device trees unchanged.

Tested on an i.MX8MM board with the AK4619 connected to GPIO1 and SSI3.


[1] AK4619 datasheet, section 2 'Power-up/down Sequence', page 39


Alexander Koch (2):
  ASoC: codecs: ak4619: Add optional PDN GPIO support
  SoC: dt-bindings: asahi-kasei,ak4619: Add PDN GPIO support

 .../devicetree/bindings/sound/asahi-kasei,ak4619.yaml     | 8 ++++++++
 sound/soc/codecs/ak4619.c                                 | 7 +++++++
 2 files changed, 15 insertions(+)

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2.55.0