driver: imx: Add PDM MICFIL driver

The Pulse Density Modulated Microphone Interface (MICFIL) is a popular
way to deliver audio from microphones to the processor in several
applications, such as mobile telephones. However, current digital-audio
systems use multibit audio signal (also known as multibit PCM) to
represent the signal. This block implements the required digital
interface to provide a 24-bits audio signal from a PDM microphone
bitstream in a configurable output sampling rate.

This patch adds initial support for PDM MICFIL IP found on i.MX8MP
board.

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

src/drivers/imx/CMakeLists.txt

@@ -22,6 +22,10 @@ if(CONFIG_IMX_SDMA)
 	endif()
 endif()
 
+if(CONFIG_IMX_MICFIL)
+	add_local_sources(sof micfil.c)
+endif()
+
 if(CONFIG_IMX_INTERRUPT_IRQSTEER)
 	add_local_sources(sof interrupt-irqsteer.c)
 elseif(CONFIG_IMX_INTERRUPT_GENERIC)

src/drivers/imx/Kconfig

@@ -21,6 +21,15 @@ config IMX_ESAI
 	help
 	  Select this to enable support for i.MX ESAI IP.
 
+config IMX_MICFIL
+	bool "i.MX MICFIL PDM driver"
+	default n
+	depends on IMX
+	help
+	  Select this to enable support for i.MX MICFIL PDM IP. This block implements
+	  the required digital interface to provide a 24-bits audio signal from a PDM
+	  microphone bitstream in a configurable output sampling rate
+
 config IMX_INTERRUPT_IRQSTEER
 	bool
 	default n

src/drivers/imx/micfil.c

@@ -0,0 +1,335 @@
+// SPDX-License-Identifier: BSD-3-Clause
+//
+// Copyright 2023 NXP
+//
+// Author: Daniel Baluta <[email protected]>
+
+#include <sof/audio/component.h>
+#include <sof/audio/format.h>
+#include <rtos/alloc.h>
+#include <sof/drivers/micfil.h>
+#include <sof/lib/dai.h>
+#include <sof/lib/dma.h>
+#include <sof/lib/memory.h>
+#include <sof/lib/pm_runtime.h>
+#include <sof/lib/uuid.h>
+#include <ipc/dai.h>
+#include <errno.h>
+#include <stddef.h>
+#include <stdint.h>
+
+LOG_MODULE_REGISTER(micfil_dai, CONFIG_SOF_LOG_LEVEL);
+
+/* dd400475-35d7-4045-ab03-0c34957d7a08 */
+DECLARE_SOF_UUID("micfil-dai", micfil_uuid, 0xdd400475, 0x35d7, 0x4045,
+		 0xab, 0x03, 0x0c, 0x34, 0x95, 0x7d, 0x7a, 0x08);
+
+DECLARE_TR_CTX(micfil_tr, SOF_UUID(micfil_uuid), LOG_LEVEL_INFO);
+
+#define MICFIL_OSR_DEFAULT		16
+/* set default gain to 2 */
+#define MICFIL_DEFAULT_ADJ_RANGE	0x22222222
+#define MICFIL_CLK_ROOT			24576000
+
+enum micfil_quality {
+	QUALITY_HIGH,
+	QUALITY_MEDIUM,
+	QUALITY_LOW,
+	QUALITY_VLOW0,
+	QUALITY_VLOW1,
+	QUALITY_VLOW2,
+};
+
+static int micfil_reset(struct dai *dai)
+{
+	dai_update_bits(dai, REG_MICFIL_CTRL1, MICFIL_CTRL1_MDIS, 0);
+	dai_update_bits(dai, REG_MICFIL_CTRL1, MICFIL_CTRL1_SRES, MICFIL_CTRL1_SRES);
+	dai_update_bits(dai, REG_MICFIL_STAT, 0xff, 0xff);
+
+	return 0;
+}
+
+static int micfil_get_hw_params(struct dai *dai,
+				struct sof_ipc_stream_params *params, int dir)
+{
+	struct micfil_pdata *micfil = dai_get_drvdata(dai);
+
+	dai_err(dai, "micfil_get_hw_params()");
+
+	params->rate = micfil->params.pdm_rate;
+	params->channels = micfil->params.pdm_ch;
+	params->buffer_fmt = SOF_IPC_BUFFER_INTERLEAVED;
+	params->frame_fmt = SOF_IPC_FRAME_S32_LE;
+
+	return 0;
+}
+
+static int micfil_set_quality(struct dai *dai)
+{
+	struct micfil_pdata *micfil = dai_get_drvdata(dai);
+	int qsel;
+
+	switch (micfil->quality) {
+	case QUALITY_HIGH:
+		qsel = MICFIL_QSEL_HIGH_QUALITY;
+		break;
+	case QUALITY_MEDIUM:
+		qsel = MICFIL_QSEL_MEDIUM_QUALITY;
+		break;
+	case QUALITY_LOW:
+		qsel = MICFIL_QSEL_LOW_QUALITY;
+		break;
+	case QUALITY_VLOW0:
+		qsel = MICFIL_QSEL_VLOW0_QUALITY;
+		break;
+	case QUALITY_VLOW1:
+		qsel = MICFIL_QSEL_VLOW1_QUALITY;
+		break;
+	case QUALITY_VLOW2:
+		qsel = MICFIL_QSEL_VLOW2_QUALITY;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	dai_update_bits(dai, REG_MICFIL_CTRL2, MICFIL_CTRL2_QSEL,
+			MICFIL_CTRL2_QSEL_BITS(qsel));
+
+	return 0;
+}
+
+/* get_pdm_clk - computes the product between k-factor and PDM_CLK rate
+ * @param dai, SOF DAI struct
+ * @param rate, output sampling rate
+ *
+ * PDM_CLK depends on Quality Mode, output sampling rate and quality
+ * mode
+ */
+static int micfil_get_pdm_clk(struct dai *dai, int rate)
+{
+	unsigned int osr;
+	unsigned int qsel;
+	unsigned int ctrl2_reg;
+	unsigned int pdm_clk = 0;
+
+	ctrl2_reg = dai_read(dai, REG_MICFIL_CTRL2);
+	osr = 16 - ((ctrl2_reg & MICFIL_CTRL2_CICOSR) >> MICFIL_CTRL2_CICOSR_SHIFT);
+	qsel = (ctrl2_reg & MICFIL_CTRL2_QSEL) >> MICFIL_CTRL2_QSEL_SHIFT;
+
+	switch (qsel) {
+	case MICFIL_QSEL_HIGH_QUALITY:
+		pdm_clk = rate * 8 * osr / 2; /* kfactor = 0.5 */
+		break;
+	case MICFIL_QSEL_MEDIUM_QUALITY:
+	case MICFIL_QSEL_VLOW0_QUALITY:
+		pdm_clk = rate * 4 * osr; /* kfactor = 1 */
+		break;
+	case MICFIL_QSEL_LOW_QUALITY:
+	case MICFIL_QSEL_VLOW1_QUALITY:
+		pdm_clk = rate * 2 * osr * 2; /* kfactor = 2 */
+		break;
+	case MICFIL_QSEL_VLOW2_QUALITY:
+		pdm_clk = rate * osr; /* kfactor = 4 */
+		break;
+	default:
+		break;
+	}
+
+	return pdm_clk;
+}
+
+static int micfil_get_clk_div(struct dai *dai, int rate)
+{
+	int pdm_clk;
+
+	pdm_clk = micfil_get_pdm_clk(dai, rate);
+	if (pdm_clk <= 0)
+		return -EINVAL;
+
+	return MICFIL_CLK_ROOT / (pdm_clk * 2);
+}
+
+static int micfil_set_clock_params(struct dai *dai, int rate)
+{
+	int clk_div;
+
+	dai_update_bits(dai, REG_MICFIL_CTRL2, MICFIL_CTRL2_CICOSR,
+			MICFIL_CTRL2_CICOSR_BITS(MICFIL_OSR_DEFAULT));
+
+	clk_div = micfil_get_clk_div(dai, rate);
+	if (clk_div < 0)
+		return -EINVAL;
+
+	dai_update_bits(dai, REG_MICFIL_CTRL2, MICFIL_CTRL2_CLKDIV,
+			MICFIL_CTRL2_CLKDIV_BITS(clk_div));
+
+	return 0;
+}
+
+static int micfil_set_config(struct dai *dai, struct ipc_config_dai *common_config,
+			     const void *spec_config)
+{
+	int i, ret;
+	unsigned int val = 0;
+	struct micfil_pdata *micfil = dai_get_drvdata(dai);
+	const struct sof_ipc_dai_config *config = spec_config;
+
+	micfil->params = config->micfil;
+
+	dai_info(dai, "micfil_set_config() dai_idx %d channels %d sampling_freq %d",
+		 common_config->dai_index, micfil->params.pdm_ch, micfil->params.pdm_rate);
+
+	/* disable the module */
+	dai_update_bits(dai, REG_MICFIL_CTRL1, MICFIL_CTRL1_PDMIEN, 0);
+
+	micfil_set_quality(dai);
+
+	/* set default gain to 2 */
+	dai_write(dai, REG_MICFIL_OUT_CTRL, MICFIL_DEFAULT_ADJ_RANGE);
+
+	/* set DC Remover in bypass mode */
+	for (i = 0; i < MICFIL_OUTPUT_CHANNELS; i++)
+		val |= MICFIL_DC_BYPASS << MICFIL_DC_CHX_SHIFT(i);
+	dai_update_bits(dai, REG_MICFIL_DC_CTRL, MICFIL_DC_CTRL_CONFIG, val);
+
+	/* FIFO WMK */
+	dai_update_bits(dai, REG_MICFIL_FIFO_CTRL, MICFIL_FIFO_CTRL_FIFOWMK,
+			MICFIL_FIFO_CTRL_FIFOWMK_BITS(31));
+
+	/* enable channels */
+	dai_update_bits(dai, REG_MICFIL_CTRL1, MICFIL_CTRL1_CHNEN,
+			((1 << micfil->params.pdm_ch) - 1));
+
+	ret = micfil_set_clock_params(dai, micfil->params.pdm_rate);
+	if (ret < 0)
+		return -EINVAL;
+
+	return 0;
+}
+
+static int micfil_get_handshake(struct dai *dai, int direction, int stream_id)
+{
+	return dai->plat_data.fifo[SOF_IPC_STREAM_CAPTURE].handshake;
+}
+
+static int micfil_get_fifo(struct dai *dai, int direction, int stream_id)
+{
+	return dai->plat_data.fifo[SOF_IPC_STREAM_CAPTURE].offset;
+}
+
+static int micfil_get_fifo_depth(struct dai *dai, int direction)
+{
+	return dai->plat_data.fifo[SOF_IPC_STREAM_CAPTURE].depth;
+}
+
+static int micfil_start(struct dai *dai)
+{
+	int ret;
+
+	dai_info(dai, "micfil_start()");
+
+	ret = micfil_reset(dai);
+	if (ret < 0) {
+		dai_err(dai, "micfil_start(): failed to reset micfil");
+		return ret;
+	}
+
+	/* DMA Interrupt Selection - DISEL bits
+	 * 00 - DMA and IRQ disabled
+	 * 01 - DMA req enabled
+	 * 10 - IRQ enabled
+	 * 11 - reserved
+	 */
+	dai_update_bits(dai, REG_MICFIL_CTRL1,
+			MICFIL_CTRL1_DISEL,
+			MICFIL_CTRL1_DISEL_BITS(MICFIL_CTRL1_DISEL_DMA));
+
+	/* Enable the module */
+	dai_update_bits(dai, REG_MICFIL_CTRL1, MICFIL_CTRL1_PDMIEN, MICFIL_CTRL1_PDMIEN);
+
+	return 0;
+}
+
+static int micfil_stop(struct dai *dai)
+{
+	dai_info(dai, "micfil_stop()");
+
+	/* Disable the module */
+	dai_update_bits(dai, REG_MICFIL_CTRL1, MICFIL_CTRL1_PDMIEN, 0);
+
+	dai_update_bits(dai, REG_MICFIL_CTRL1, MICFIL_CTRL1_DISEL,
+			MICFIL_CTRL1_DISEL_BITS(MICFIL_CTRL1_DISEL_DISABLE));
+
+	return 0;
+}
+
+static int micfil_trigger(struct dai *dai, int cmd, int direction)
+{
+	dai_info(dai, "micfil_trigger() cmd %d dir %d", cmd, direction);
+
+	switch (cmd) {
+	case COMP_TRIGGER_START:
+	case COMP_TRIGGER_RELEASE:
+		micfil_start(dai);
+		break;
+	case COMP_TRIGGER_STOP:
+	case COMP_TRIGGER_PAUSE:
+		micfil_stop(dai);
+	case COMP_TRIGGER_PRE_START:
+	case COMP_TRIGGER_PRE_RELEASE:
+		break;
+	default:
+		dai_err(dai, "MICFIL: invalid trigger cmd %d", cmd);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int micfil_probe(struct dai *dai)
+{
+	struct micfil_pdata *micfil;
+
+	dai_info(dai, "micfil_probe()");
+
+	micfil = rzalloc(SOF_MEM_ZONE_RUNTIME_SHARED, 0, SOF_MEM_CAPS_RAM, sizeof(*micfil));
+	if (!micfil) {
+		dai_err(dai, "micfil probe failed");
+		return -ENOMEM;
+	}
+
+	micfil->quality = QUALITY_VLOW0;
+
+	dai_set_drvdata(dai, micfil);
+
+	return 0;
+}
+
+static int micfil_remove(struct dai *dai)
+{
+	struct micfil_pdata *micfil = dai_get_drvdata(dai);
+
+	dai_info(dai, "micfil_remove()");
+
+	rfree(micfil);
+	dai_set_drvdata(dai, NULL);
+
+	return 0;
+}
+
+const struct dai_driver micfil_driver = {
+	.type = SOF_DAI_IMX_MICFIL,
+	.uid = SOF_UUID(micfil_uuid),
+	.tctx = &micfil_tr,
+	.dma_dev = DMA_DEV_MICFIL,
+	.ops = {
+		.trigger		= micfil_trigger,
+		.set_config		= micfil_set_config,
+		.get_hw_params		= micfil_get_hw_params,
+		.get_handshake		= micfil_get_handshake,
+		.get_fifo		= micfil_get_fifo,
+		.get_fifo_depth		= micfil_get_fifo_depth,
+		.probe			= micfil_probe,
+		.remove			= micfil_remove,
+	},
+};

src/include/ipc/dai-imx.h

@@ -54,4 +54,11 @@ struct sof_ipc_dai_sai_params {
 	uint16_t reserved2;	/* alignment */
 
 } __attribute__((packed, aligned(4)));
+
+/* MICFIL Configuration Request - SOF_IPC_DAI_MICFIL_CONFIG */
+struct sof_ipc_dai_micfil_params {
+	uint32_t pdm_rate;
+	uint32_t pdm_ch;
+} __attribute__((packed, aligned(4)));
+
 #endif /* __IPC_DAI_IMX_H__ */

src/include/ipc/dai.h

@@ -92,7 +92,8 @@ enum sof_ipc_dai_type {
 	SOF_DAI_MEDIATEK_AFE,           /**< Mtk AFE */
 	SOF_DAI_AMD_HS,			/**< Amd HS */
 	SOF_DAI_AMD_SP_VIRTUAL,		/**<Amd SP VIRTUAL */
-	SOF_DAI_AMD_HS_VIRTUAL		/**<Amd HS VIRTUAL */
+	SOF_DAI_AMD_HS_VIRTUAL,		/**<Amd HS VIRTUAL */
+	SOF_DAI_IMX_MICFIL,		/**< i.MX MICFIL */
 };
 
 /* general purpose DAI configuration */
@@ -122,6 +123,7 @@ struct sof_ipc_dai_config {
 		struct sof_ipc_dai_acpdmic_params acpdmic;
 		struct sof_ipc_dai_acp_params acphs;
 		struct sof_ipc_dai_afe_params afe;
+		struct sof_ipc_dai_micfil_params micfil;
 	};
 } __attribute__((packed, aligned(4)));