Hello,
Some devices have a 4-pin jack instead of a 3-pin and currently the WM8903 configuration is hardcoded to the case of 3-pin jack in the Tegra's ASoC driver. A new device-tree property is required in order to convey that hardware has a 4-pin jack, and thus, microphone's detection needs to be done in a different way.
In particular this is needed for Acer A500 tablet device that has a 4-pin headset jack, otherwise userspace sees headset instead of headphones and internal microphone isn't enabled by ALSA UCM rule when it should be. Please review and apply, thanks in advance.
Dmitry Osipenko (2): dt-bindings: sound: tegra-wm8903: Document new nvidia,headset property ASoC: tegra: tegra_wm8903: Support nvidia,headset property
.../devicetree/bindings/sound/nvidia,tegra-audio-wm8903.txt | 1 + sound/soc/tegra/tegra_wm8903.c | 6 +++++- 2 files changed, 6 insertions(+), 1 deletion(-)