[PATCH 0/4] ASoC: meson: aiu: align I2S design to the AXG one

[Valerio Setti]

This is the first follow-up patch series based on RFC [1]. The goal here
is simply to reshape Amlogic GX's AIU implementation for I2S to follow
the same design as in AXG's TDM. Keeping the same design allows for
unifying the two platform implementations in the future.

The first commit introduces gx-formatter as the basic block which takes
care of properly formatting audio data. Formatters are DAPM widgets
(c.f. axg-tdm-formatter in AXG) which are dynamically attached/detached
to the streams when the latters starts/stop, respectively.
aiu-formatter-i2s is introduced as formatter implementation for the i2s
output.

By the end aiu-encoder-i2s will only need to handle interface clocks and
enforce interface wide rate symmetry (c.f axg-tdm-interface on the AXG
platform). Right now rate symmetry is not relevant because only i2s output
is supported, but it will become useful when following patch series will
introduce the i2s input part.

This series was tested on an OdroidC2 board (Amlogic S905 SOC) with an
NXP SGTL5000 codec connected to its I2S input port.

Changes from RFC:
- Use devm_ variant of snd_soc_register_component in gx_formatte_probe.
- Return on failures in aiu_encoder_i2s_set_sysclk.
- MCLK and i2s_divider clocks enablement moved from hw_params() to
  prepare(). Stream's "clk_enabled" is used as simple refcounting to
  prevent multiple enable/disable.
- Improved the mechanism to ensure rate symmetry on the interface.
  Previous implementation had issues with alsaloop when both capture and
  playback streams are opened before any hw_params is set on any of them.

Thanks to Mark Brown and Jerome Brunet for the review of the RFC.

[1]: https://lore.kernel.org/linux-sound/20260411-audin-rfc-v2-0-4c8a6ec5fcab@baylibre.com/

Signed-off-by: Valerio Setti <vsetti at baylibre.com>
---
Valerio Setti (4):
      ASoC: meson: gx: add gx-formatter and gx-interface
      ASoC: meson: aiu-encoder-i2s: use gx_iface and gx_stream structures
      ASoC: meson: aiu: introduce I2S output formatter
      ASoC: meson: aiu: use aiu-formatter-i2s to format I2S output data

 sound/soc/meson/Makefile            |   2 +
 sound/soc/meson/aiu-encoder-i2s.c   | 250 +++++++++++++++++++++-----------
 sound/soc/meson/aiu-formatter-i2s.c | 106 ++++++++++++++
 sound/soc/meson/aiu.c               |  30 +++-
 sound/soc/meson/aiu.h               |   4 +
 sound/soc/meson/gx-formatter.c      | 277 ++++++++++++++++++++++++++++++++++++
 sound/soc/meson/gx-formatter.h      |  47 ++++++
 sound/soc/meson/gx-interface.h      |  45 ++++++
 8 files changed, 675 insertions(+), 86 deletions(-)
---
base-commit: 254f49634ee16a731174d2ae34bc50bd5f45e731
change-id: 20260515-reshape-aiu-as-axg-1dac9037cad3

Best regards,
-- 
Valerio Setti <vsetti at baylibre.com>