[PATCH v3 3/6] ASoC: atmel: mchp-pdmc: add PDMC driver

[Codrin Ciubotariu <codrin.ciubotariu@microchip.com>]

The Pulse Density Microphone Controller (PDMC) interfaces up to 4 digital
microphones having Pulse Density Modulated (PDM) outputs. It generates a
single clock line and samples 1 or 2 data lines. The signal path includes
an audio grade programmable decimation filter and outputs 24-bit audio
words on the APB bus.

Signed-off-by: Codrin Ciubotariu <codrin.ciubotariu@microchip.com>
---

Changes in v3:
 - none

Changes in v2:
 - replaced included file dt-bindings/sound/mchp,pdmc.h wih
   dt-bindings/sound/microchip,pdmc.h

 sound/soc/atmel/Kconfig     |   16 +
 sound/soc/atmel/Makefile    |    2 +
 sound/soc/atmel/mchp-pdmc.c | 1084 +++++++++++++++++++++++++++++++++++
 3 files changed, 1102 insertions(+)
 create mode 100644 sound/soc/atmel/mchp-pdmc.c

diff --git a/sound/soc/atmel/Kconfig b/sound/soc/atmel/Kconfig
index 8617793ed955..795c0b0b527a 100644
--- a/sound/soc/atmel/Kconfig
+++ b/sound/soc/atmel/Kconfig
@@ -160,4 +160,20 @@ config SND_MCHP_SOC_SPDIFRX
 
 	  This S/PDIF RX driver is compliant with IEC-60958 standard and
 	  includes programmable User Data and Channel Status fields.
+
+config SND_MCHP_SOC_PDMC
+	tristate "Microchip ASoC driver for boards using PDMC"
+	depends on OF && (ARCH_AT91 || COMPILE_TEST)
+	select SND_SOC_GENERIC_DMAENGINE_PCM
+	select REGMAP_MMIO
+	help
+	  Say Y or M if you want to add support for Microchip ASoC PDMC driver on the
+	  following Microchip platforms:
+	  - sama7g5
+
+	  The Pulse Density Microphone Controller (PDMC) interfaces up to 4 digital
+	  microphones PDM outputs. It generates a single clock line and samples 1 or
+	  2 data lines. The signal path includes an audio grade programmable
+	  decimation filter and outputs 24-bit audio words.
+
 endif
diff --git a/sound/soc/atmel/Makefile b/sound/soc/atmel/Makefile
index 016188397210..043097a08ea8 100644
--- a/sound/soc/atmel/Makefile
+++ b/sound/soc/atmel/Makefile
@@ -7,6 +7,7 @@ snd-soc-atmel-i2s-objs := atmel-i2s.o
 snd-soc-mchp-i2s-mcc-objs := mchp-i2s-mcc.o
 snd-soc-mchp-spdiftx-objs := mchp-spdiftx.o
 snd-soc-mchp-spdifrx-objs := mchp-spdifrx.o
+snd-soc-mchp-pdmc-objs := mchp-pdmc.o
 
 # pdc and dma need to both be built-in if any user of
 # ssc is built-in.
@@ -21,6 +22,7 @@ obj-$(CONFIG_SND_ATMEL_SOC_I2S) += snd-soc-atmel-i2s.o
 obj-$(CONFIG_SND_MCHP_SOC_I2S_MCC) += snd-soc-mchp-i2s-mcc.o
 obj-$(CONFIG_SND_MCHP_SOC_SPDIFTX) += snd-soc-mchp-spdiftx.o
 obj-$(CONFIG_SND_MCHP_SOC_SPDIFRX) += snd-soc-mchp-spdifrx.o
+obj-$(CONFIG_SND_MCHP_SOC_PDMC) += snd-soc-mchp-pdmc.o
 
 # AT91 Machine Support
 snd-soc-sam9g20-wm8731-objs := sam9g20_wm8731.o
diff --git a/sound/soc/atmel/mchp-pdmc.c b/sound/soc/atmel/mchp-pdmc.c
new file mode 100644
index 000000000000..c44636f6207d
--- /dev/null
+++ b/sound/soc/atmel/mchp-pdmc.c
@@ -0,0 +1,1084 @@
+// SPDX-License-Identifier: GPL-2.0
+//
+// Driver for Microchip Pulse Density Microphone Controller (PDMC) interfaces
+//
+// Copyright (C) 2019-2022 Microchip Technology Inc. and its subsidiaries
+//
+// Author: Codrin Ciubotariu <codrin.ciubotariu@microchip.com>
+
+#include <dt-bindings/sound/microchip,pdmc.h>
+
+#include <linux/clk.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/regmap.h>
+
+#include <sound/core.h>
+#include <sound/dmaengine_pcm.h>
+#include <sound/pcm_params.h>
+#include <sound/tlv.h>
+
+/*
+ * ---- PDMC Register map ----
+ */
+#define MCHP_PDMC_CR			0x00	/* Control Register */
+#define MCHP_PDMC_MR			0x04	/* Mode Register */
+#define MCHP_PDMC_CFGR			0x08	/* Configuration Register */
+#define MCHP_PDMC_RHR			0x0C	/* Receive Holding Register */
+#define MCHP_PDMC_IER			0x14	/* Interrupt Enable Register */
+#define MCHP_PDMC_IDR			0x18	/* Interrupt Disable Register */
+#define MCHP_PDMC_IMR			0x1C	/* Interrupt Mask Register */
+#define MCHP_PDMC_ISR			0x20	/* Interrupt Status Register */
+#define MCHP_PDMC_VER			0x50	/* Version Register */
+
+/*
+ * ---- Control Register (Write-only) ----
+ */
+#define MCHP_PDMC_CR_SWRST		BIT(0)	/* Software Reset */
+
+/*
+ * ---- Mode Register (Read/Write) ----
+ */
+#define MCHP_PDMC_MR_PDMCEN_MASK	GENMASK(3, 0)
+#define MCHP_PDMC_MR_PDMCEN(ch)		(BIT(ch) & MCHP_PDMC_MR_PDMCEN_MASK)
+
+#define MCHP_PDMC_MR_OSR_MASK		GENMASK(17, 16)
+#define MCHP_PDMC_MR_OSR64		(1 << 16)
+#define MCHP_PDMC_MR_OSR128		(2 << 16)
+#define MCHP_PDMC_MR_OSR256		(3 << 16)
+
+#define MCHP_PDMC_MR_SINCORDER_MASK	GENMASK(23, 20)
+#define MCHP_PDMC_MR_SINCORDER(order)	(((order) << 20) & \
+					 MCHP_PDMC_MR_SINCORDER_MASK)
+
+#define MCHP_PDMC_MR_SINC_OSR_MASK	GENMASK(27, 24)
+#define MCHP_PDMC_MR_SINC_OSR_DIS	(0 << 24)
+#define MCHP_PDMC_MR_SINC_OSR_8		(1 << 24)
+#define MCHP_PDMC_MR_SINC_OSR_16	(2 << 24)
+#define MCHP_PDMC_MR_SINC_OSR_32	(3 << 24)
+#define MCHP_PDMC_MR_SINC_OSR_64	(4 << 24)
+#define MCHP_PDMC_MR_SINC_OSR_128	(5 << 24)
+#define MCHP_PDMC_MR_SINC_OSR_256	(6 << 24)
+
+#define MCHP_PDMC_MR_CHUNK_MASK		GENMASK(31, 28)
+#define MCHP_PDMC_MR_CHUNK(chunk)	(((chunk) << 28) & \
+					 MCHP_PDMC_MR_CHUNK_MASK)
+
+/*
+ * ---- Configuration Register (Read/Write) ----
+ */
+#define MCHP_PDMC_CFGR_BSSEL_MASK	(BIT(0) | BIT(2) | BIT(4) | BIT(6))
+#define MCHP_PDMC_CFGR_BSSEL(ch)	BIT((ch) * 2)
+
+#define MCHP_PDMC_CFGR_PDMSEL_MASK	(BIT(16) | BIT(18) | BIT(20) | BIT(22))
+#define MCHP_PDMC_CFGR_PDMSEL(ch)	BIT((ch) * 2 + 16)
+
+/*
+ * ---- Interrupt Enable/Disable/Mask/Status Registers ----
+ */
+#define MCHP_PDMC_IR_RXRDY		BIT(0)
+#define MCHP_PDMC_IR_RXEMPTY		BIT(1)
+#define MCHP_PDMC_IR_RXFULL		BIT(2)
+#define MCHP_PDMC_IR_RXCHUNK		BIT(3)
+#define MCHP_PDMC_IR_RXUDR		BIT(4)
+#define MCHP_PDMC_IR_RXOVR		BIT(5)
+
+/*
+ * ---- Version Register (Read-only) ----
+ */
+#define MCHP_PDMC_VER_VERSION		GENMASK(11, 0)
+
+#define MCHP_PDMC_MAX_CHANNELS		4
+#define MCHP_PDMC_DS_NO			2
+#define MCHP_PDMC_EDGE_NO		2
+
+struct mic_map {
+	int ds_pos;
+	int clk_edge;
+};
+
+struct mchp_pdmc_chmap {
+	struct snd_pcm_chmap_elem *chmap;
+	struct mchp_pdmc *dd;
+	struct snd_pcm *pcm;
+	struct snd_kcontrol *kctl;
+};
+
+struct mchp_pdmc {
+	struct mic_map channel_mic_map[MCHP_PDMC_MAX_CHANNELS];
+	struct device *dev;
+	struct snd_dmaengine_dai_dma_data addr;
+	struct regmap *regmap;
+	struct clk *pclk;
+	struct clk *gclk;
+	u32 pdmcen;
+	int mic_no;
+	int sinc_order;
+	bool audio_filter_en;
+	u8 gclk_enabled:1;
+};
+
+static const char *const mchp_pdmc_sinc_filter_order_text[] = {
+	"1", "2", "3", "4", "5"
+};
+
+static const unsigned int mchp_pdmc_sinc_filter_order_values[] = {
+	1, 2, 3, 4, 5,
+};
+
+static const struct soc_enum mchp_pdmc_sinc_filter_order_enum = {
+	.items = ARRAY_SIZE(mchp_pdmc_sinc_filter_order_text),
+	.texts = mchp_pdmc_sinc_filter_order_text,
+	.values = mchp_pdmc_sinc_filter_order_values,
+};
+
+static int mchp_pdmc_sinc_order_get(struct snd_kcontrol *kcontrol,
+				    struct snd_ctl_elem_value *uvalue)
+{
+	struct snd_soc_component *component = snd_kcontrol_chip(kcontrol);
+	struct mchp_pdmc *dd = snd_soc_component_get_drvdata(component);
+	struct soc_enum *e = (struct soc_enum *)kcontrol->private_value;
+	unsigned int item;
+
+	item = snd_soc_enum_val_to_item(e, dd->sinc_order);
+	uvalue->value.enumerated.item[0] = item;
+
+	return 0;
+}
+
+static int mchp_pdmc_sinc_order_put(struct snd_kcontrol *kcontrol,
+				    struct snd_ctl_elem_value *uvalue)
+{
+	struct snd_soc_component *component = snd_kcontrol_chip(kcontrol);
+	struct mchp_pdmc *dd = snd_soc_component_get_drvdata(component);
+	struct soc_enum *e = (struct soc_enum *)kcontrol->private_value;
+	unsigned int *item = uvalue->value.enumerated.item;
+	unsigned int val;
+
+	if (item[0] >= e->items)
+		return -EINVAL;
+
+	val = snd_soc_enum_item_to_val(e, item[0]) << e->shift_l;
+	if (val == dd->sinc_order)
+		return 0;
+
+	dd->sinc_order = val;
+
+	return 1;
+}
+
+static int mchp_pdmc_af_get(struct snd_kcontrol *kcontrol,
+			    struct snd_ctl_elem_value *uvalue)
+{
+	struct snd_soc_component *component = snd_kcontrol_chip(kcontrol);
+	struct mchp_pdmc *dd = snd_soc_component_get_drvdata(component);
+
+	uvalue->value.integer.value[0] = !!dd->audio_filter_en;
+
+	return 0;
+}
+
+static int mchp_pdmc_af_put(struct snd_kcontrol *kcontrol,
+			    struct snd_ctl_elem_value *uvalue)
+{
+	struct snd_soc_component *component = snd_kcontrol_chip(kcontrol);
+	struct mchp_pdmc *dd = snd_soc_component_get_drvdata(component);
+	bool af = uvalue->value.integer.value ? true : false;
+
+	if (dd->audio_filter_en == af)
+		return 0;
+
+	dd->audio_filter_en = af;
+
+	return 1;
+}
+
+static int mchp_pdmc_chmap_ctl_info(struct snd_kcontrol *kcontrol, struct snd_ctl_elem_info *uinfo)
+{
+	struct mchp_pdmc_chmap *info = snd_kcontrol_chip(kcontrol);
+
+	uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
+	uinfo->count = info->dd->mic_no;
+	uinfo->value.integer.min = 0;
+	uinfo->value.integer.max = SNDRV_CHMAP_RR; /* maxmimum 4 channels */
+	return 0;
+}
+
+static inline struct snd_pcm_substream *
+mchp_pdmc_chmap_substream(struct mchp_pdmc_chmap *info, unsigned int idx)
+{
+	struct snd_pcm_substream *s;
+
+	for (s = info->pcm->streams[SNDRV_PCM_STREAM_CAPTURE].substream; s; s = s->next)
+		if (s->number == idx)
+			return s;
+	return NULL;
+}
+
+static struct snd_pcm_chmap_elem *mchp_pdmc_chmap_get(struct snd_pcm_substream *substream,
+						      struct mchp_pdmc_chmap *ch_info)
+{
+	struct snd_pcm_chmap_elem *map;
+
+	for (map = ch_info->chmap; map->channels; map++) {
+		if (map->channels == substream->runtime->channels)
+			return map;
+	}
+	return NULL;
+}
+
+static int mchp_pdmc_chmap_ctl_get(struct snd_kcontrol *kcontrol,
+				   struct snd_ctl_elem_value *ucontrol)
+{
+	struct mchp_pdmc_chmap *info = snd_kcontrol_chip(kcontrol);
+	struct mchp_pdmc *dd = info->dd;
+	unsigned int idx = snd_ctl_get_ioffidx(kcontrol, &ucontrol->id);
+	struct snd_pcm_substream *substream;
+	const struct snd_pcm_chmap_elem *map;
+	int i;
+	u32 cfgr_val = 0;
+
+	if (!info->chmap)
+		return -EINVAL;
+	substream = mchp_pdmc_chmap_substream(info, idx);
+	if (!substream)
+		return -ENODEV;
+	memset(ucontrol->value.integer.value, 0, sizeof(long) * info->dd->mic_no);
+	if (!substream->runtime)
+		return 0; /* no channels set */
+
+	map = mchp_pdmc_chmap_get(substream, info);
+	if (!map)
+		return -EINVAL;
+
+	for (i = 0; i < map->channels; i++) {
+		int map_idx = map->channels == 1 ? map->map[i] - SNDRV_CHMAP_MONO :
+						   map->map[i] - SNDRV_CHMAP_FL;
+
+		/* make sure the reported channel map is the real one, so write the map */
+		if (dd->channel_mic_map[map_idx].ds_pos)
+			cfgr_val |= MCHP_PDMC_CFGR_PDMSEL(i);
+		if (dd->channel_mic_map[map_idx].clk_edge)
+			cfgr_val |= MCHP_PDMC_CFGR_BSSEL(i);
+
+		ucontrol->value.integer.value[i] = map->map[i];
+	}
+
+	regmap_write(dd->regmap, MCHP_PDMC_CFGR, cfgr_val);
+
+	return 0;
+}
+
+static int mchp_pdmc_chmap_ctl_put(struct snd_kcontrol *kcontrol,
+				   struct snd_ctl_elem_value *ucontrol)
+{
+	struct mchp_pdmc_chmap *info = snd_kcontrol_chip(kcontrol);
+	struct mchp_pdmc *dd = info->dd;
+	unsigned int idx = snd_ctl_get_ioffidx(kcontrol, &ucontrol->id);
+	struct snd_pcm_substream *substream;
+	struct snd_pcm_chmap_elem *map;
+	u32 cfgr_val = 0;
+	int i;
+
+	if (!info->chmap)
+		return -EINVAL;
+	substream = mchp_pdmc_chmap_substream(info, idx);
+	if (!substream)
+		return -ENODEV;
+
+	map = mchp_pdmc_chmap_get(substream, info);
+	if (!map)
+		return -EINVAL;
+
+	for (i = 0; i < map->channels; i++) {
+		int map_idx;
+
+		map->map[i] = ucontrol->value.integer.value[i];
+		map_idx = map->channels == 1 ? map->map[i] - SNDRV_CHMAP_MONO :
+					       map->map[i] - SNDRV_CHMAP_FL;
+
+		/* configure IP for the desired channel map */
+		if (dd->channel_mic_map[map_idx].ds_pos)
+			cfgr_val |= MCHP_PDMC_CFGR_PDMSEL(i);
+		if (dd->channel_mic_map[map_idx].clk_edge)
+			cfgr_val |= MCHP_PDMC_CFGR_BSSEL(i);
+	}
+
+	regmap_write(dd->regmap, MCHP_PDMC_CFGR, cfgr_val);
+
+	return 0;
+}
+
+static void mchp_pdmc_chmap_ctl_private_free(struct snd_kcontrol *kcontrol)
+{
+	struct mchp_pdmc_chmap *info = snd_kcontrol_chip(kcontrol);
+
+	info->pcm->streams[SNDRV_PCM_STREAM_CAPTURE].chmap_kctl = NULL;
+	kfree(info);
+}
+
+static int mchp_pdmc_chmap_ctl_tlv(struct snd_kcontrol *kcontrol, int op_flag,
+				   unsigned int size, unsigned int __user *tlv)
+{
+	struct mchp_pdmc_chmap *info = snd_kcontrol_chip(kcontrol);
+	const struct snd_pcm_chmap_elem *map;
+	unsigned int __user *dst;
+	int c, count = 0;
+
+	if (!info->chmap)
+		return -EINVAL;
+	if (size < 8)
+		return -ENOMEM;
+	if (put_user(SNDRV_CTL_TLVT_CONTAINER, tlv))
+		return -EFAULT;
+	size -= 8;
+	dst = tlv + 2;
+	for (map = info->chmap; map->channels; map++) {
+		int chs_bytes = map->channels * 4;
+
+		if (size < 8)
+			return -ENOMEM;
+		if (put_user(SNDRV_CTL_TLVT_CHMAP_VAR, dst) ||
+		    put_user(chs_bytes, dst + 1))
+			return -EFAULT;
+		dst += 2;
+		size -= 8;
+		count += 8;
+		if (size < chs_bytes)
+			return -ENOMEM;
+		size -= chs_bytes;
+		count += chs_bytes;
+		for (c = 0; c < map->channels; c++) {
+			if (put_user(map->map[c], dst))
+				return -EFAULT;
+			dst++;
+		}
+	}
+	if (put_user(count, tlv + 1))
+		return -EFAULT;
+	return 0;
+}
+
+static const struct snd_kcontrol_new mchp_pdmc_snd_controls[] = {
+	SOC_SINGLE_BOOL_EXT("Audio Filter", 0, &mchp_pdmc_af_get, &mchp_pdmc_af_put),
+	{
+		.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+		.name = "SINC Filter Order",
+		.info = snd_soc_info_enum_double,
+		.get = mchp_pdmc_sinc_order_get,
+		.put = mchp_pdmc_sinc_order_put,
+		.private_value = (unsigned long)&mchp_pdmc_sinc_filter_order_enum,
+	},
+};
+
+static int mchp_pdmc_close(struct snd_soc_component *component,
+			   struct snd_pcm_substream *substream)
+{
+	return snd_soc_add_component_controls(component, mchp_pdmc_snd_controls,
+					      ARRAY_SIZE(mchp_pdmc_snd_controls));
+}
+
+static int mchp_pdmc_open(struct snd_soc_component *component,
+			  struct snd_pcm_substream *substream)
+{
+	int i;
+
+	/* remove controls that can't be changed at runtime */
+	for (i = 0; i < ARRAY_SIZE(mchp_pdmc_snd_controls); i++) {
+		const struct snd_kcontrol_new *control = &mchp_pdmc_snd_controls[i];
+		struct snd_ctl_elem_id id;
+		struct snd_kcontrol *kctl;
+		int err;
+
+		if (component->name_prefix)
+			snprintf(id.name, sizeof(id.name), "%s %s", component->name_prefix,
+				 control->name);
+		else
+			strscpy(id.name, control->name, sizeof(id.name));
+
+		id.numid = 0;
+		id.iface = control->iface;
+		id.device = control->device;
+		id.subdevice = control->subdevice;
+		id.index = control->index;
+		kctl = snd_ctl_find_id(component->card->snd_card, &id);
+		if (!kctl) {
+			dev_err(component->dev, "Failed to find %s\n", control->name);
+			continue;
+		}
+		err = snd_ctl_remove(component->card->snd_card, kctl);
+		if (err < 0) {
+			dev_err(component->dev, "%d: Failed to remove %s\n", err,
+				control->name);
+			continue;
+		}
+	}
+
+	return 0;
+}
+
+static const struct snd_soc_component_driver mchp_pdmc_dai_component = {
+	.name = "mchp-pdmc",
+	.controls = mchp_pdmc_snd_controls,
+	.num_controls = ARRAY_SIZE(mchp_pdmc_snd_controls),
+	.open = &mchp_pdmc_open,
+	.close = &mchp_pdmc_close,
+};
+
+static const unsigned int mchp_pdmc_1mic[] = {1};
+static const unsigned int mchp_pdmc_2mic[] = {1, 2};
+static const unsigned int mchp_pdmc_3mic[] = {1, 2, 3};
+static const unsigned int mchp_pdmc_4mic[] = {1, 2, 3, 4};
+
+static const struct snd_pcm_hw_constraint_list mchp_pdmc_chan_constr[] = {
+	{
+		.list = mchp_pdmc_1mic,
+		.count = ARRAY_SIZE(mchp_pdmc_1mic),
+	},
+	{
+		.list = mchp_pdmc_2mic,
+		.count = ARRAY_SIZE(mchp_pdmc_2mic),
+	},
+	{
+		.list = mchp_pdmc_3mic,
+		.count = ARRAY_SIZE(mchp_pdmc_3mic),
+	},
+	{
+		.list = mchp_pdmc_4mic,
+		.count = ARRAY_SIZE(mchp_pdmc_4mic),
+	},
+};
+
+static int mchp_pdmc_startup(struct snd_pcm_substream *substream,
+			     struct snd_soc_dai *dai)
+{
+	struct mchp_pdmc *dd = snd_soc_dai_get_drvdata(dai);
+	int ret;
+
+	ret = clk_prepare_enable(dd->pclk);
+	if (ret) {
+		dev_err(dd->dev, "failed to enable the peripheral clock: %d\n", ret);
+		return ret;
+	}
+
+	regmap_write(dd->regmap, MCHP_PDMC_CR, MCHP_PDMC_CR_SWRST);
+
+	snd_pcm_hw_constraint_list(substream->runtime, 0, SNDRV_PCM_HW_PARAM_CHANNELS,
+				   &mchp_pdmc_chan_constr[dd->mic_no - 1]);
+
+	return 0;
+}
+
+static void mchp_pdmc_shutdown(struct snd_pcm_substream *substream,
+			       struct snd_soc_dai *dai)
+{
+	struct mchp_pdmc *dd = snd_soc_dai_get_drvdata(dai);
+
+	clk_disable_unprepare(dd->pclk);
+}
+
+static int mchp_pdmc_dai_probe(struct snd_soc_dai *dai)
+{
+	struct mchp_pdmc *dd = snd_soc_dai_get_drvdata(dai);
+
+	snd_soc_dai_init_dma_data(dai, NULL, &dd->addr);
+
+	return 0;
+}
+
+static int mchp_pdmc_set_fmt(struct snd_soc_dai *dai, unsigned int fmt)
+{
+	unsigned int fmt_master = fmt & SND_SOC_DAIFMT_MASTER_MASK;
+	unsigned int fmt_format = fmt & SND_SOC_DAIFMT_FORMAT_MASK;
+
+	/* IP needs to be bitclock master */
+	if (fmt_master != SND_SOC_DAIFMT_CBS_CFS &&
+	    fmt_master != SND_SOC_DAIFMT_CBS_CFM)
+		return -EINVAL;
+
+	/* IP supports only PDM interface */
+	if (fmt_format != SND_SOC_DAIFMT_PDM)
+		return -EINVAL;
+
+	return 0;
+}
+
+static u32 mchp_pdmc_mr_set_osr(int audio_filter_en, unsigned int osr)
+{
+	if (audio_filter_en) {
+		switch (osr) {
+		case 64:
+			return MCHP_PDMC_MR_OSR64;
+		case 128:
+			return MCHP_PDMC_MR_OSR128;
+		case 256:
+			return MCHP_PDMC_MR_OSR256;
+		}
+	} else {
+		switch (osr) {
+		case 8:
+			return MCHP_PDMC_MR_SINC_OSR_8;
+		case 16:
+			return MCHP_PDMC_MR_SINC_OSR_16;
+		case 32:
+			return MCHP_PDMC_MR_SINC_OSR_32;
+		case 64:
+			return MCHP_PDMC_MR_SINC_OSR_64;
+		case 128:
+			return MCHP_PDMC_MR_SINC_OSR_128;
+		case 256:
+			return MCHP_PDMC_MR_SINC_OSR_256;
+		}
+	}
+	return 0;
+}
+
+static inline int mchp_pdmc_period_to_maxburst(int period_size)
+{
+	if (!(period_size % 8))
+		return 8;
+	if (!(period_size % 4))
+		return 4;
+	if (!(period_size % 2))
+		return 2;
+	return 1;
+}
+
+static struct snd_pcm_chmap_elem mchp_pdmc_std_chmaps[] = {
+	{ .channels = 1,
+	  .map = { SNDRV_CHMAP_MONO } },
+	{ .channels = 2,
+	  .map = { SNDRV_CHMAP_FL, SNDRV_CHMAP_FR } },
+	{ .channels = 3,
+	  .map = { SNDRV_CHMAP_FL, SNDRV_CHMAP_FR,
+		   SNDRV_CHMAP_RL } },
+	{ .channels = 4,
+	  .map = { SNDRV_CHMAP_FL, SNDRV_CHMAP_FR,
+		   SNDRV_CHMAP_RL, SNDRV_CHMAP_RR } },
+	{ }
+};
+
+static int mchp_pdmc_hw_params(struct snd_pcm_substream *substream,
+			       struct snd_pcm_hw_params *params,
+			       struct snd_soc_dai *dai)
+{
+	struct mchp_pdmc *dd = snd_soc_dai_get_drvdata(dai);
+	struct snd_soc_component *comp = dai->component;
+	unsigned long gclk_rate = 0;
+	unsigned long best_diff_rate = ~0UL;
+	unsigned int channels = params_channels(params);
+	unsigned int osr = 0, osr_start;
+	unsigned int fs = params_rate(params);
+	u32 mr_val = 0;
+	u32 cfgr_val = 0;
+	int i;
+	int ret;
+
+	dev_dbg(comp->dev, "%s() rate=%u format=%#x width=%u channels=%u\n",
+		__func__, params_rate(params), params_format(params),
+		params_width(params), params_channels(params));
+
+	if (channels > dd->mic_no) {
+		dev_err(comp->dev, "more channels %u than microphones %d\n",
+			channels, dd->mic_no);
+		return -EINVAL;
+	}
+
+	dd->pdmcen = 0;
+	for (i = 0; i < channels; i++) {
+		dd->pdmcen |= MCHP_PDMC_MR_PDMCEN(i);
+		if (dd->channel_mic_map[i].ds_pos)
+			cfgr_val |= MCHP_PDMC_CFGR_PDMSEL(i);
+		if (dd->channel_mic_map[i].clk_edge)
+			cfgr_val |= MCHP_PDMC_CFGR_BSSEL(i);
+	}
+
+	if (dd->gclk_enabled) {
+		clk_disable_unprepare(dd->gclk);
+		dd->gclk_enabled = 0;
+	}
+
+	for (osr_start = dd->audio_filter_en ? 64 : 8;
+	     osr_start <= 256 && best_diff_rate; osr_start *= 2) {
+		long round_rate;
+		unsigned long diff_rate;
+
+		round_rate = clk_round_rate(dd->gclk,
+					    (unsigned long)fs * 16 * osr_start);
+		if (round_rate < 0)
+			continue;
+		diff_rate = abs((fs * 16 * osr_start) - round_rate);
+		if (diff_rate < best_diff_rate) {
+			best_diff_rate = diff_rate;
+			osr = osr_start;
+			gclk_rate = fs * 16 * osr;
+		}
+	}
+	if (!gclk_rate) {
+		dev_err(comp->dev, "invalid sampling rate: %u\n", fs);
+		return -EINVAL;
+	}
+
+	/* set the rate */
+	ret = clk_set_rate(dd->gclk, gclk_rate);
+	if (ret) {
+		dev_err(comp->dev, "unable to set rate %lu to GCLK: %d\n",
+			gclk_rate, ret);
+		return ret;
+	}
+
+	mr_val |= mchp_pdmc_mr_set_osr(dd->audio_filter_en, osr);
+
+	mr_val |= MCHP_PDMC_MR_SINCORDER(dd->sinc_order);
+
+	dd->addr.maxburst = mchp_pdmc_period_to_maxburst(snd_pcm_lib_period_bytes(substream));
+	mr_val |= MCHP_PDMC_MR_CHUNK(dd->addr.maxburst);
+	dev_dbg(comp->dev, "maxburst set to %d\n", dd->addr.maxburst);
+
+	clk_prepare_enable(dd->gclk);
+	dd->gclk_enabled = 1;
+
+	snd_soc_component_update_bits(comp, MCHP_PDMC_MR,
+				      MCHP_PDMC_MR_OSR_MASK |
+				      MCHP_PDMC_MR_SINCORDER_MASK |
+				      MCHP_PDMC_MR_SINC_OSR_MASK |
+				      MCHP_PDMC_MR_CHUNK_MASK, mr_val);
+
+	snd_soc_component_write(comp, MCHP_PDMC_CFGR, cfgr_val);
+
+	return 0;
+}
+
+static int mchp_pdmc_hw_free(struct snd_pcm_substream *substream,
+			     struct snd_soc_dai *dai)
+{
+	struct mchp_pdmc *dd = snd_soc_dai_get_drvdata(dai);
+
+	if (dd->gclk_enabled) {
+		clk_disable_unprepare(dd->gclk);
+		dd->gclk_enabled = 0;
+	}
+
+	return 0;
+}
+
+static int mchp_pdmc_trigger(struct snd_pcm_substream *substream,
+			     int cmd, struct snd_soc_dai *dai)
+{
+	struct mchp_pdmc *dd = snd_soc_dai_get_drvdata(dai);
+	struct snd_soc_component *cpu = dai->component;
+#ifdef DEBUG
+	u32 val;
+#endif
+
+	switch (cmd) {
+	case SNDRV_PCM_TRIGGER_START:
+	case SNDRV_PCM_TRIGGER_RESUME:
+	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
+		/* Enable overrun and underrun error interrupts */
+		regmap_write(dd->regmap, MCHP_PDMC_IER,
+			     MCHP_PDMC_IR_RXOVR | MCHP_PDMC_IR_RXUDR);
+		snd_soc_component_update_bits(cpu, MCHP_PDMC_MR,
+					      MCHP_PDMC_MR_PDMCEN_MASK,
+					      dd->pdmcen);
+		break;
+	case SNDRV_PCM_TRIGGER_STOP:
+	case SNDRV_PCM_TRIGGER_SUSPEND:
+	case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
+		/* Disable overrun and underrun error interrupts */
+		regmap_write(dd->regmap, MCHP_PDMC_IDR,
+			     MCHP_PDMC_IR_RXOVR | MCHP_PDMC_IR_RXUDR);
+		snd_soc_component_update_bits(cpu, MCHP_PDMC_MR,
+					      MCHP_PDMC_MR_PDMCEN_MASK, 0);
+		break;
+	default:
+		return -EINVAL;
+	}
+
+#ifdef DEBUG
+	regmap_read(dd->regmap, MCHP_PDMC_MR, &val);
+	dev_dbg(dd->dev, "MR (0x%02x): 0x%08x\n", MCHP_PDMC_MR, val);
+	regmap_read(dd->regmap, MCHP_PDMC_CFGR, &val);
+	dev_dbg(dd->dev, "CFGR (0x%02x): 0x%08x\n", MCHP_PDMC_CFGR, val);
+	regmap_read(dd->regmap, MCHP_PDMC_IMR, &val);
+	dev_dbg(dd->dev, "IMR (0x%02x): 0x%08x\n", MCHP_PDMC_IMR, val);
+#endif
+
+	return 0;
+}
+
+static const struct snd_soc_dai_ops mchp_pdmc_dai_ops = {
+	.set_fmt	= mchp_pdmc_set_fmt,
+	.startup	= mchp_pdmc_startup,
+	.shutdown	= mchp_pdmc_shutdown,
+	.hw_params	= mchp_pdmc_hw_params,
+	.hw_free	= mchp_pdmc_hw_free,
+	.trigger	= mchp_pdmc_trigger,
+};
+
+static int mchp_pdmc_add_chmap_ctls(struct snd_pcm *pcm, struct mchp_pdmc *dd)
+{
+	struct mchp_pdmc_chmap *info;
+	struct snd_kcontrol_new knew = {
+		.iface = SNDRV_CTL_ELEM_IFACE_PCM,
+		.access = SNDRV_CTL_ELEM_ACCESS_READWRITE |
+			SNDRV_CTL_ELEM_ACCESS_TLV_READ |
+			SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK,
+		.info = mchp_pdmc_chmap_ctl_info,
+		.get = mchp_pdmc_chmap_ctl_get,
+		.put = mchp_pdmc_chmap_ctl_put,
+		.tlv.c = mchp_pdmc_chmap_ctl_tlv,
+	};
+	int err;
+
+	if (WARN_ON(pcm->streams[SNDRV_PCM_STREAM_CAPTURE].chmap_kctl))
+		return -EBUSY;
+	info = kzalloc(sizeof(*info), GFP_KERNEL);
+	if (!info)
+		return -ENOMEM;
+	info->pcm = pcm;
+	info->dd = dd;
+	info->chmap = mchp_pdmc_std_chmaps;
+	knew.name = "Capture Channel Map";
+	knew.device = pcm->device;
+	knew.count = pcm->streams[SNDRV_PCM_STREAM_CAPTURE].substream_count;
+	info->kctl = snd_ctl_new1(&knew, info);
+	if (!info->kctl) {
+		kfree(info);
+		return -ENOMEM;
+	}
+	info->kctl->private_free = mchp_pdmc_chmap_ctl_private_free;
+	err = snd_ctl_add(pcm->card, info->kctl);
+	if (err < 0)
+		return err;
+	pcm->streams[SNDRV_PCM_STREAM_CAPTURE].chmap_kctl = info->kctl;
+	return 0;
+}
+
+static int mchp_pdmc_pcm_new(struct snd_soc_pcm_runtime *rtd,
+			     struct snd_soc_dai *dai)
+{
+	struct mchp_pdmc *dd = snd_soc_dai_get_drvdata(dai);
+	int ret;
+
+	ret = mchp_pdmc_add_chmap_ctls(rtd->pcm, dd);
+	if (ret < 0) {
+		dev_err(dd->dev, "failed to add channel map controls: %d\n", ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+static struct snd_soc_dai_driver mchp_pdmc_dai = {
+	.probe	= mchp_pdmc_dai_probe,
+	.capture = {
+		.stream_name	= "Capture",
+		.channels_min	= 1,
+		.channels_max	= 4,
+		.rate_min	= 8000,
+		.rate_max	= 192000,
+		.rates		= SNDRV_PCM_RATE_KNOT,
+		.formats	= SNDRV_PCM_FMTBIT_S24_LE,
+	},
+	.ops = &mchp_pdmc_dai_ops,
+	.pcm_new = &mchp_pdmc_pcm_new,
+};
+
+/* PDMC interrupt handler */
+static irqreturn_t mchp_pdmc_interrupt(int irq, void *dev_id)
+{
+	struct mchp_pdmc *dd = (struct mchp_pdmc *)dev_id;
+	u32 isr, msr, pending;
+	irqreturn_t ret = IRQ_NONE;
+
+	regmap_read(dd->regmap, MCHP_PDMC_ISR, &isr);
+	regmap_read(dd->regmap, MCHP_PDMC_IMR, &msr);
+
+	pending = isr & msr;
+	dev_dbg(dd->dev, "ISR (0x%02x): 0x%08x, IMR (0x%02x): 0x%08x, pending: 0x%08x\n",
+		MCHP_PDMC_ISR, isr, MCHP_PDMC_IMR, msr, pending);
+	if (!pending)
+		return IRQ_NONE;
+
+	if (pending & MCHP_PDMC_IR_RXUDR) {
+		dev_warn(dd->dev, "underrun detected\n");
+		regmap_write(dd->regmap, MCHP_PDMC_IDR, MCHP_PDMC_IR_RXUDR);
+		ret = IRQ_HANDLED;
+	}
+	if (pending & MCHP_PDMC_IR_RXOVR) {
+		dev_warn(dd->dev, "overrun detected\n");
+		regmap_write(dd->regmap, MCHP_PDMC_IDR, MCHP_PDMC_IR_RXOVR);
+		ret = IRQ_HANDLED;
+	}
+
+	return ret;
+}
+
+/* regmap configuration */
+static bool mchp_pdmc_readable_reg(struct device *dev, unsigned int reg)
+{
+	switch (reg) {
+	case MCHP_PDMC_MR:
+	case MCHP_PDMC_CFGR:
+	case MCHP_PDMC_IMR:
+	case MCHP_PDMC_ISR:
+	case MCHP_PDMC_VER:
+		return true;
+	default:
+		return false;
+	}
+}
+
+static bool mchp_pdmc_writeable_reg(struct device *dev, unsigned int reg)
+{
+	switch (reg) {
+	case MCHP_PDMC_CR:
+	case MCHP_PDMC_MR:
+	case MCHP_PDMC_CFGR:
+	case MCHP_PDMC_IER:
+	case MCHP_PDMC_IDR:
+		return true;
+	default:
+		return false;
+	}
+}
+
+static bool mchp_pdmc_precious_reg(struct device *dev, unsigned int reg)
+{
+	switch (reg) {
+	case MCHP_PDMC_RHR:
+	case MCHP_PDMC_ISR:
+		return true;
+	default:
+		return false;
+	}
+}
+
+static const struct regmap_config mchp_pdmc_regmap_config = {
+	.reg_bits	= 32,
+	.reg_stride	= 4,
+	.val_bits	= 32,
+	.max_register	= MCHP_PDMC_VER,
+	.readable_reg	= mchp_pdmc_readable_reg,
+	.writeable_reg	= mchp_pdmc_writeable_reg,
+	.precious_reg	= mchp_pdmc_precious_reg,
+};
+
+static int mchp_pdmc_dt_init(struct mchp_pdmc *dd)
+{
+	struct device_node *np = dd->dev->of_node;
+	bool mic_ch[MCHP_PDMC_DS_NO][MCHP_PDMC_EDGE_NO] = {0};
+	int i;
+	int ret;
+
+	if (!np) {
+		dev_err(dd->dev, "device node not found\n");
+		return -EINVAL;
+	}
+
+	dd->mic_no = of_property_count_u32_elems(np, "microchip,mic-pos");
+	if (dd->mic_no < 0) {
+		dev_err(dd->dev, "failed to get mchp,mic-pos: %d",
+			dd->mic_no);
+		return dd->mic_no;
+	}
+	if (!dd->mic_no || dd->mic_no % 2 ||
+	    dd->mic_no / 2 > MCHP_PDMC_MAX_CHANNELS) {
+		dev_err(dd->dev, "invalid array length for mchp,mic-pos: %d",
+			dd->mic_no);
+		return -EINVAL;
+	}
+
+	dd->mic_no /= 2;
+
+	dev_info(dd->dev, "%d PDM microchopnes declared\n", dd->mic_no);
+
+	/* by default, we consider the order of microphones in mchp,mic-pos to
+	 * be the same with the channel mapping; 1st microphone channel 0, 2nd
+	 * microphone channel 1, etc.
+	 */
+	for (i = 0; i < dd->mic_no; i++) {
+		int ds;
+		int edge;
+
+		ret = of_property_read_u32_index(np, "microchip,mic-pos", i * 2,
+						 &ds);
+		if (ret) {
+			dev_err(dd->dev,
+				"failed to get value no %d value from microchip,mic-pos: %d",
+				i * 2, ret);
+			return ret;
+		}
+		if (ds >= MCHP_PDMC_DS_NO) {
+			dev_err(dd->dev,
+				"invalid DS index in microchip,mic-pos array: %d",
+				ds);
+			return -EINVAL;
+		}
+
+		ret = of_property_read_u32_index(np, "microchip,mic-pos", i * 2 + 1,
+						 &edge);
+		if (ret) {
+			dev_err(dd->dev,
+				"failed to get value no %d value from microchip,mic-pos: %d",
+				i * 2 + 1, ret);
+			return ret;
+		}
+
+		if (edge != MCHP_PDMC_CLK_POSITIVE &&
+		    edge != MCHP_PDMC_CLK_NEGATIVE) {
+			dev_err(dd->dev,
+				"invalid edge in microchip,mic-pos array: %d", edge);
+			return -EINVAL;
+		}
+		if (mic_ch[ds][edge]) {
+			dev_err(dd->dev,
+				"duplicated mic (DS %d, edge %d) in microchip,mic-pos array",
+				ds, edge);
+			return -EINVAL;
+		}
+		mic_ch[ds][edge] = true;
+		dd->channel_mic_map[i].ds_pos = ds;
+		dd->channel_mic_map[i].clk_edge = edge;
+	}
+
+	return 0;
+}
+
+/* used to clean the channel index found on RHR's MSB */
+static int mchp_pdmc_process(struct snd_pcm_substream *substream,
+			     int channel, unsigned long hwoff,
+			     void *buf, unsigned long bytes)
+{
+	struct snd_pcm_runtime *runtime = substream->runtime;
+	u8 *dma_ptr = runtime->dma_area + hwoff +
+		      channel * (runtime->dma_bytes / runtime->channels);
+	u8 *dma_ptr_end = dma_ptr + bytes;
+	unsigned int sample_size = samples_to_bytes(runtime, 1);
+
+	for (; dma_ptr < dma_ptr_end; dma_ptr += sample_size)
+		*dma_ptr = 0;
+
+	return 0;
+}
+
+static struct snd_dmaengine_pcm_config mchp_pdmc_config = {
+	.process = mchp_pdmc_process,
+};
+
+static int mchp_pdmc_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct mchp_pdmc *dd;
+	struct resource *res;
+	void __iomem *io_base;
+	u32 version;
+	int irq;
+	int ret;
+
+	dd = devm_kzalloc(dev, sizeof(*dd), GFP_KERNEL);
+	if (!dd)
+		return -ENOMEM;
+
+	dd->dev = &pdev->dev;
+	ret =  mchp_pdmc_dt_init(dd);
+	if (ret < 0)
+		return ret;
+
+	irq = platform_get_irq(pdev, 0);
+	if (irq < 0) {
+		dev_err(dev, "failed to get irq: %d\n", irq);
+		return irq;
+	}
+
+	dd->pclk = devm_clk_get(dev, "pclk");
+	if (IS_ERR(dd->pclk)) {
+		ret = PTR_ERR(dd->pclk);
+		dev_err(dev, "failed to get peripheral clock: %d\n", ret);
+		return ret;
+	}
+
+	dd->gclk = devm_clk_get(dev, "gclk");
+	if (IS_ERR(dd->gclk)) {
+		ret = PTR_ERR(dd->gclk);
+		dev_err(dev, "failed to get GCK: %d\n", ret);
+		return ret;
+	}
+
+	io_base = devm_platform_get_and_ioremap_resource(pdev, 0, &res);
+	if (IS_ERR(io_base)) {
+		ret = PTR_ERR(io_base);
+		dev_err(dev, "failed to remap register memory: %d\n", ret);
+		return ret;
+	}
+
+	dd->regmap = devm_regmap_init_mmio(dev, io_base,
+					   &mchp_pdmc_regmap_config);
+	if (IS_ERR(dd->regmap)) {
+		ret = PTR_ERR(dd->regmap);
+		dev_err(dev, "failed to init register map: %d\n", ret);
+		return ret;
+	}
+
+	ret = devm_request_irq(dev, irq, mchp_pdmc_interrupt, 0,
+			       dev_name(&pdev->dev), (void *)dd);
+	if (ret < 0) {
+		dev_err(dev, "can't register ISR for IRQ %u (ret=%i)\n",
+			irq, ret);
+		return ret;
+	}
+
+	/* by default audio filter is enabled and the SINC Filter order
+	 * will be set to the recommended value, 3
+	 */
+	dd->audio_filter_en = true;
+	dd->sinc_order = 3;
+
+	dd->addr.addr = (dma_addr_t)res->start + MCHP_PDMC_RHR;
+	platform_set_drvdata(pdev, dd);
+
+	/* register platform */
+	ret = devm_snd_dmaengine_pcm_register(dev, &mchp_pdmc_config, 0);
+	if (ret) {
+		dev_err(dev, "could not register platform: %d\n", ret);
+		return ret;
+	}
+
+	ret = devm_snd_soc_register_component(dev, &mchp_pdmc_dai_component,
+					      &mchp_pdmc_dai, 1);
+	if (ret) {
+		dev_err(dev, "could not register CPU DAI: %d\n", ret);
+		return ret;
+	}
+
+	/* print IP version */
+	regmap_read(dd->regmap, MCHP_PDMC_VER, &version);
+	dev_info(dd->dev, "hw version: %#lx\n",
+		 version & MCHP_PDMC_VER_VERSION);
+
+	return 0;
+}
+
+static const struct of_device_id mchp_pdmc_of_match[] = {
+	{
+		.compatible = "microchip,sama7g5-pdmc",
+	}, {
+		/* sentinel */
+	}
+};
+MODULE_DEVICE_TABLE(of, mchp_pdmc_of_match);
+
+static struct platform_driver mchp_pdmc_driver = {
+	.driver	= {
+		.name		= "mchp-pdmc",
+		.of_match_table	= of_match_ptr(mchp_pdmc_of_match),
+		.pm		= &snd_soc_pm_ops,
+	},
+	.probe	= mchp_pdmc_probe,
+};
+module_platform_driver(mchp_pdmc_driver);
+
+MODULE_DESCRIPTION("Microchip PDMC driver under ALSA SoC architecture");
+MODULE_AUTHOR("Codrin Ciubotariu <codrin.ciubotariu@microchip.com>");
+MODULE_LICENSE("GPL v2");
-- 
2.32.0