linux-kernel - [PATCH 5/7] ASoC: soc-dai: add common operation to set TDM idle mode

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Message-Id: <20251209-tdm-idle-slots-v1-5-38dabf6bc01e@gmail.com>
Date: Tue, 09 Dec 2025 19:31:18 +1000
From: James Calligeros <jcalligeros99@...il.com>
To: Liam Girdwood <lgirdwood@...il.com>, Mark Brown <broonie@...nel.org>, 
 Rob Herring <robh@...nel.org>, Krzysztof Kozlowski <krzk+dt@...nel.org>, 
 Conor Dooley <conor+dt@...nel.org>, Shawn Guo <shawnguo@...nel.org>, 
 Sascha Hauer <s.hauer@...gutronix.de>, 
 Pengutronix Kernel Team <kernel@...gutronix.de>, 
 Fabio Estevam <festevam@...il.com>, 
 Kuninori Morimoto <kuninori.morimoto.gx@...esas.com>, 
 Shengjiu Wang <shengjiu.wang@....com>, Jaroslav Kysela <perex@...ex.cz>, 
 Takashi Iwai <tiwai@...e.com>, Shenghao Ding <shenghao-ding@...com>, 
 Kevin Lu <kevin-lu@...com>, Baojun Xu <baojun.xu@...com>
Cc: linux-sound@...r.kernel.org, devicetree@...r.kernel.org, 
 imx@...ts.linux.dev, linux-arm-kernel@...ts.infradead.org, 
 linux-kernel@...r.kernel.org, asahi@...ts.linux.dev, 
 James Calligeros <jcalligeros99@...il.com>
Subject: [PATCH 5/7] ASoC: soc-dai: add common operation to set TDM idle
 mode

Some audio devices, like certain Texas Instruments codecs, can be
configured to alter their behaviour when idle on the bus. Now that we
have definitions for various idle modes, add a snd_soc_dai_set_tdm_idle()
operation to control this in a standardised way.

Signed-off-by: James Calligeros <jcalligeros99@...il.com>
---
 include/sound/soc-dai.h |  7 +++++
 sound/soc/soc-dai.c     | 40 +++++++++++++++++++++++++
 2 files changed, 47 insertions(+)

diff --git a/include/sound/soc-dai.h b/include/sound/soc-dai.h
index a5784ef8e3f7..1f411237dde5 100644
--- a/include/sound/soc-dai.h
+++ b/include/sound/soc-dai.h
@@ -194,6 +194,10 @@ int snd_soc_dai_set_fmt(struct snd_soc_dai *dai, unsigned int fmt);
 int snd_soc_dai_set_tdm_slot(struct snd_soc_dai *dai,
 	unsigned int tx_mask, unsigned int rx_mask, int slots, int slot_width);
 
+int snd_soc_dai_set_tdm_idle(struct snd_soc_dai *dai,
+			     unsigned int tx_mask, unsigned int rx_mask,
+			     int tx_mode, int rx_mode);
+
 int snd_soc_dai_set_channel_map(struct snd_soc_dai *dai,
 	unsigned int tx_num, const unsigned int *tx_slot,
 	unsigned int rx_num, const unsigned int *rx_slot);
@@ -310,6 +314,9 @@ struct snd_soc_dai_ops {
 	int (*set_tdm_slot)(struct snd_soc_dai *dai,
 		unsigned int tx_mask, unsigned int rx_mask,
 		int slots, int slot_width);
+	int (*set_tdm_idle)(struct snd_soc_dai *dai,
+			    unsigned int tx_mask, unsigned int rx_mask,
+			    int tx_mode, int rx_mode);
 	int (*set_channel_map)(struct snd_soc_dai *dai,
 		unsigned int tx_num, const unsigned int *tx_slot,
 		unsigned int rx_num, const unsigned int *rx_slot);
diff --git a/sound/soc/soc-dai.c b/sound/soc/soc-dai.c
index a1e05307067d..2f370fda1266 100644
--- a/sound/soc/soc-dai.c
+++ b/sound/soc/soc-dai.c
@@ -282,6 +282,46 @@ int snd_soc_dai_set_tdm_slot(struct snd_soc_dai *dai,
 }
 EXPORT_SYMBOL_GPL(snd_soc_dai_set_tdm_slot);
 
+/**
+ * snd_soc_dai_set_tdm_idle() - Configure a DAI's TDM idle mode
+ * @dai: The DAI to configure
+ * @tx_mask: bitmask representing idle TX slots.
+ * @rx_mask: bitmask representing idle RX slots.
+ * @tx_mode: idle mode to set for TX slots.
+ * @rx_mode: idle mode to set for RX slots.
+ *
+ * This function configures the DAI to handle idle TDM slots in the
+ * specified manner. @tx_mode and @rx_mode can be one of
+ * SND_SOC_DAI_TDM_IDLE_NONE, SND_SOC_DAI_TDM_IDLE_ZERO,
+ * SND_SOC_DAI_TDM_IDLE_PULLDOWN, or SND_SOC_DAI_TDM_IDLE_HIZ.
+ * SND_SOC_TDM_IDLE_NONE represents the DAI's default/unset idle slot
+ * handling state and could be any of the other modes depending on the
+ * hardware behind the DAI. It is therefore undefined behaviour when set
+ * explicitly.
+ *
+ * Mode and mask can be set independently for both the TX and RX direction.
+ * Some hardware may ignore both TX and RX masks depending on its
+ * capabilities.
+ */
+int snd_soc_dai_set_tdm_idle(struct snd_soc_dai *dai,
+			     unsigned int tx_mask, unsigned int rx_mask,
+			     int tx_mode, int rx_mode)
+{
+	int ret = -EOPNOTSUPP;
+
+	/* You can't write to the RX line */
+	if (rx_mode == SND_SOC_DAI_TDM_IDLE_ZERO)
+		return soc_dai_ret(dai, -EINVAL);
+
+	if (dai->driver->ops &&
+	    dai->driver->ops->set_tdm_idle)
+		ret = dai->driver->ops->set_tdm_idle(dai, tx_mask, rx_mask,
+						     tx_mode, rx_mode);
+
+	return soc_dai_ret(dai, ret);
+}
+EXPORT_SYMBOL_GPL(snd_soc_dai_set_tdm_idle);
+
 /**
  * snd_soc_dai_set_channel_map - configure DAI audio channel map
  * @dai: DAI

-- 
2.52.0