drivers: dai: Add initial support for NXP MICFIL PDM IP

Introduce new DAI driver used for NXP's PDM MICFIL IP.
This block implements required digital interface to provide
a 24-bits audio signal from a PDM microphone bitstream in a configurable
output sampling rate.

Signed-off-by: Daniel Baluta <[email protected]>

drivers/dai/CMakeLists.txt

@@ -6,3 +6,4 @@ add_subdirectory_ifdef(CONFIG_DAI_INTEL_DMIC intel/dmic)
 add_subdirectory_ifdef(CONFIG_DAI_INTEL_HDA intel/hda)
 add_subdirectory_ifdef(CONFIG_DAI_NXP_SAI nxp/sai)
 add_subdirectory_ifdef(CONFIG_DAI_NXP_ESAI nxp/esai)
+add_subdirectory_ifdef(CONFIG_DAI_NXP_MICFIL nxp/micfil)

drivers/dai/Kconfig

@@ -31,5 +31,6 @@ source "drivers/dai/intel/dmic/Kconfig.dmic"
 source "drivers/dai/intel/hda/Kconfig.hda"
 source "drivers/dai/nxp/sai/Kconfig.sai"
 source "drivers/dai/nxp/esai/Kconfig.esai"
+source "drivers/dai/nxp/micfil/Kconfig.micfil"
 
 endif # DAI

drivers/dai/nxp/micfil/CMakeLists.txt

@@ -0,0 +1,5 @@
+# Copyright 2025 NXP
+# SPDX-License-Identifier: Apache-2.0
+
+zephyr_library()
+zephyr_library_sources(micfil.c)

drivers/dai/nxp/micfil/Kconfig.micfil

@@ -0,0 +1,10 @@
+# Copyright 2025 NXP
+# SPDX-License-Identifier: Apache-2.0
+
+config DAI_NXP_MICFIL
+	bool "NXP Pulse Density Modulation Microphone Interface (MICFIL) driver"
+	default y
+	depends on DT_HAS_NXP_DAI_MICFIL_ENABLED
+	select PINCTRL
+	help
+		Select this to enable NXP PDM MICFIL driver.

drivers/dai/nxp/micfil/micfil.c

@@ -0,0 +1,210 @@
+/*
+ * Copyright 2025 NXP
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+#include <zephyr/drivers/dai.h>
+#include <zephyr/device.h>
+#include <zephyr/kernel.h>
+#include <zephyr/drivers/pinctrl.h>
+#include <zephyr/logging/log.h>
+
+#include "fsl_pdm.h"
+
+#define DT_DRV_COMPAT nxp_dai_micfil
+LOG_MODULE_REGISTER(nxp_dai_micfil);
+
+#define MICFIL_CLK_ROOT 24576000
+#define MICFIL_OSR_DEFAULT	16
+
+#define UINT_TO_MICFIL(x) ((PDM_Type *)(uintptr_t)(x))
+
+#define MICFIL_FIFO_BASE(inst) \
+	POINTER_TO_UINT(&(UINT_TO_MICFIL(DT_INST_REG_ADDR(inst))->DATACH[0]))
+
+#define MICFIL_DMA_HANDSHAKE(inst) \
+	((DT_INST_DMAS_CELL_BY_IDX(inst, 0, channel) & GENMASK(7, 0)) | \
+	((DT_INST_DMAS_CELL_BY_IDX(inst, 0, mux) << 8) & GENMASK(15, 8)))
+
+struct dai_nxp_micfil_data {
+	struct dai_config cfg;
+};
+
+struct dai_nxp_micfil_config {
+	PDM_Type *base;
+	const struct dai_properties *rx_props;
+	const struct pinctrl_dev_config *pincfg;
+};
+
+/* this needs to match SOF struct sof_ipc_dai_micfil_params */
+struct micfil_bespoke_config {
+	uint32_t pdm_rate;
+	uint32_t pdm_ch;
+};
+
+static void dai_nxp_micfil_trigger_start(const struct device *dev)
+{
+	const struct dai_nxp_micfil_config *cfg = dev->config;
+
+	/* enable DMA requests */
+	PDM_EnableDMA(cfg->base, true);
+	/* enable the module */
+	PDM_Enable(cfg->base, true);
+}
+
+static void dai_nxp_micfil_trigger_stop(const struct device *dev)
+{
+	const struct dai_nxp_micfil_config *cfg = dev->config;
+
+	/* disable DMA requests */
+	PDM_EnableDMA(cfg->base, false);
+	/* disable module */
+	PDM_Enable(cfg->base, false);
+}
+
+static const struct dai_properties
+*dai_nxp_micfil_get_properties(const struct device *dev, enum dai_dir dir, int stream_id)
+{
+	const struct dai_nxp_micfil_config *cfg = dev->config;
+
+	if (dir == DAI_DIR_RX) {
+		return cfg->rx_props;
+	}
+
+	LOG_ERR("invalid direction %d", dir);
+	return NULL;
+}
+
+static int dai_nxp_micfil_trigger(const struct device *dev, enum dai_dir dir,
+				  enum dai_trigger_cmd cmd)
+{
+	if (dir != DAI_DIR_RX) {
+		LOG_ERR("invalid direction %d", dir);
+		return -EINVAL;
+	}
+
+	switch (cmd) {
+	case DAI_TRIGGER_START:
+		dai_nxp_micfil_trigger_start(dev);
+		break;
+	case DAI_TRIGGER_STOP:
+	case DAI_TRIGGER_PAUSE:
+		dai_nxp_micfil_trigger_stop(dev);
+		break;
+	case DAI_TRIGGER_PRE_START:
+	case DAI_TRIGGER_COPY:
+		return 0;
+	default:
+		LOG_ERR("invalid trigger cmd %d", cmd);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int dai_nxp_micfil_get_config(const struct device *dev, struct dai_config *cfg,
+				     enum dai_dir dir)
+{
+	struct dai_nxp_micfil_data *micfil_data = dev->data;
+
+	memcpy(cfg, &micfil_data->cfg, sizeof(*cfg));
+	return 0;
+}
+
+static int dai_nxp_micfil_set_config(const struct device *dev,
+		const struct dai_config *cfg, const void *bespoke_cfg)
+
+{
+	const struct micfil_bespoke_config *bespoke = bespoke_cfg;
+	const struct dai_nxp_micfil_config *micfil_cfg = dev->config;
+	pdm_channel_config_t chan_config = { 0 };
+	pdm_config_t global_config = { 0 };
+	int ret, i;
+
+	if (cfg->type != DAI_IMX_MICFIL) {
+		LOG_ERR("wrong DAI type: %d", cfg->type);
+		return -EINVAL;
+	}
+
+	global_config.fifoWatermark = micfil_cfg->rx_props->fifo_depth - 1;
+	global_config.qualityMode = kPDM_QualityModeVeryLow0;
+	global_config.cicOverSampleRate = MICFIL_OSR_DEFAULT;
+
+	PDM_Init(micfil_cfg->base, &global_config);
+
+	for (i = 0; i < bespoke->pdm_ch; i++) {
+		chan_config.gain = kPDM_DfOutputGain2;
+		chan_config.cutOffFreq = kPDM_DcRemoverBypass;
+		PDM_SetChannelConfig(micfil_cfg->base, i, &chan_config);
+	}
+
+	ret = PDM_SetSampleRateConfig(micfil_cfg->base, MICFIL_CLK_ROOT, bespoke->pdm_rate);
+	if (ret == kStatus_Fail) {
+		LOG_ERR("Failure to set samplerate config rate %d", bespoke->pdm_rate);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int dai_nxp_micfil_probe(const struct device *dev)
+{
+	/* nothing do to here, but mandatory to exist */
+	return 0;
+}
+
+static int dai_nxp_micfil_remove(const struct device *dev)
+{
+	/* nothing do to here, but mandatory to exist */
+	return 0;
+}
+
+const struct dai_driver_api dai_nxp_micfil_ops = {
+	.probe			= dai_nxp_micfil_probe,
+	.remove			= dai_nxp_micfil_remove,
+	.config_set		= dai_nxp_micfil_set_config,
+	.config_get		= dai_nxp_micfil_get_config,
+	.get_properties		= dai_nxp_micfil_get_properties,
+	.trigger		= dai_nxp_micfil_trigger,
+};
+
+static int micfil_init(const struct device *dev)
+{
+	const struct dai_nxp_micfil_config *cfg = dev->config;
+	int ret;
+
+	/* pinctrl is optional so do not return an error if not
+	 * defined */
+	ret = pinctrl_apply_state(cfg->pincfg, PINCTRL_STATE_DEFAULT);
+	if (ret < 0 && ret != -ENOENT) {
+		return ret;
+	}
+
+	return 0;
+}
+
+#define DAI_NXP_MICFIL_INIT(inst)						\
+PINCTRL_DT_INST_DEFINE(inst);							\
+static struct dai_nxp_micfil_data dai_nxp_micfil_data_##inst = {		\
+	.cfg.type = DAI_IMX_MICFIL,						\
+	.cfg.dai_index = DT_INST_PROP_OR(inst, dai_index, 0),			\
+};										\
+										\
+static const struct dai_properties micfil_rx_props_##inst = {			\
+	.fifo_address = MICFIL_FIFO_BASE(inst),					\
+	.fifo_depth = DT_INST_PROP(inst, fifo_depth),			\
+	.dma_hs_id = MICFIL_DMA_HANDSHAKE(inst),				\
+};										\
+										\
+static const struct dai_nxp_micfil_config dai_nxp_micfil_config_##inst = {	\
+	.base = UINT_TO_MICFIL(DT_INST_REG_ADDR(inst)),				\
+	.rx_props = &micfil_rx_props_##inst,					\
+	.pincfg = PINCTRL_DT_INST_DEV_CONFIG_GET(inst),				\
+};										\
+										\
+DEVICE_DT_INST_DEFINE(inst, &micfil_init, NULL,					\
+	      &dai_nxp_micfil_data_##inst, &dai_nxp_micfil_config_##inst,	\
+	      POST_KERNEL, CONFIG_DAI_INIT_PRIORITY,				\
+	      &dai_nxp_micfil_ops);						\
+
+DT_INST_FOREACH_STATUS_OKAY(DAI_NXP_MICFIL_INIT)

dts/bindings/dai/nxp,dai-micfil.yaml

@@ -0,0 +1,25 @@
+# Copyright 2023 NXP
+# SPDX-License-Identifier: Apache-2.0
+
+description: NXP PDM MICFIL node
+
+compatible: "nxp,dai-micfil"
+
+include: [base.yaml, pinctrl-device.yaml]
+
+properties:
+  reg:
+    required: true
+  dai-index:
+    type: int
+    description: |
+      Use this property to specify the index of the DAI. At the
+      moment, this is only used by SOF to fetch the "struct device"
+      associated with the DAI whose index Linux passes to SOF
+      through an IPC. If this property is not specified, the DAI
+      index will be considered 0.
+  fifo-depth:
+    type: int
+    required: true
+    description: |
+      Depth (in words) for each channel's FIFO.