The ASP1 DOUT line must be defaulted to be high-impedance when it is not actually transmitting data for an active channel.

In non-SoundWire modes ASP1 will usually be shared by multiple amps so each amp must only drive the line during the slot for an enabled TX channel.

In SoundWire mode a custom firmware can use ASP1 as a secondary chip-to-chip audio link or as GPIO. It should be defaulted to high-impedance since by default the purpose of this pin is not known.

Backport note: On kernel versions before 6.6 the cs35l56->base.regmap argument to regmap_set_bits() must be changed to cs35l56->regmap.

Signed-off-by: Richard Fitzgerald rf@opensource.cirrus.com Fixes: e49611252900 ("ASoC: cs35l56: Add driver for Cirrus Logic CS35L56") --- sound/soc/codecs/cs35l56.c | 6 ++++++ 1 file changed, 6 insertions(+)

diff --git a/sound/soc/codecs/cs35l56.c b/sound/soc/codecs/cs35l56.c index 8ccdd3f134a5..45b4de3eff94 100644 --- a/sound/soc/codecs/cs35l56.c +++ b/sound/soc/codecs/cs35l56.c @@ -1197,6 +1197,12 @@ int cs35l56_init(struct cs35l56_private *cs35l56) /* Registers could be dirty after soft reset or SoundWire enumeration */ regcache_sync(cs35l56->base.regmap);

+ /* Set ASP1 DOUT to high-impedance when it is not transmitting audio data. */ + ret = regmap_set_bits(cs35l56->base.regmap, CS35L56_ASP1_CONTROL3, + CS35L56_ASP1_DOUT_HIZ_CTRL_MASK); + if (ret) + return dev_err_probe(cs35l56->base.dev, ret, "Failed to write ASP1_CONTROL3\n"); + cs35l56->base.init_done = true; complete(&cs35l56->init_completion);