root/sound/soc/atmel/mchp-pdmc.c
// 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/bitfield.h>
#include <linux/clk.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/pm_runtime.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_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)

/*
 * ---- 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

/*
 * ---- DMA chunk size allowed ----
 */
#define MCHP_PDMC_DMA_8_WORD_CHUNK                      8
#define MCHP_PDMC_DMA_4_WORD_CHUNK                      4
#define MCHP_PDMC_DMA_2_WORD_CHUNK                      2
#define MCHP_PDMC_DMA_1_WORD_CHUNK                      1
#define DMA_BURST_ALIGNED(_p, _s, _w)           !(_p % (_s * _w))

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;
        u32 suspend_irq;
        u32 startup_delay_us;
        int mic_no;
        int sinc_order;
        bool audio_filter_en;
        atomic_t busy_stream;
};

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 (atomic_read(&dd->busy_stream))
                return -EBUSY;

        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[0] ? true : false;

        if (atomic_read(&dd->busy_stream))
                return -EBUSY;

        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;

        if (!substream->runtime)
                return 0; /* just for avoiding error from alsactl restore */

        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 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),
};

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);

        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 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_BP_FP &&
            fmt_master != SND_SOC_DAIFMT_BP_FC)
                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, int sample_size)
{
        int p_size = period_size;
        int s_size = sample_size;

        if (DMA_BURST_ALIGNED(p_size, s_size, MCHP_PDMC_DMA_8_WORD_CHUNK))
                return MCHP_PDMC_DMA_8_WORD_CHUNK;
        if (DMA_BURST_ALIGNED(p_size, s_size, MCHP_PDMC_DMA_4_WORD_CHUNK))
                return MCHP_PDMC_DMA_4_WORD_CHUNK;
        if (DMA_BURST_ALIGNED(p_size, s_size, MCHP_PDMC_DMA_2_WORD_CHUNK))
                return MCHP_PDMC_DMA_2_WORD_CHUNK;
        return MCHP_PDMC_DMA_1_WORD_CHUNK;
}

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);
        int sample_bytes = params_physical_width(params) / 8;
        int period_bytes = params_period_size(params) *
                params_channels(params) * sample_bytes;
        int maxburst;
        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 period_bytes=%d\n",
                __func__, params_rate(params), params_format(params),
                params_width(params), params_channels(params), period_bytes);

        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);
        }

        /*
         * from these point forward, we consider the controller busy, so the
         * audio filter and SINC order can't be changed
         */
        atomic_set(&dd->busy_stream, 1);
        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;
        }

        /* CLK is enabled by runtime PM. */
        clk_disable_unprepare(dd->gclk);

        /* set the rate */
        ret = clk_set_rate(dd->gclk, gclk_rate);
        clk_prepare_enable(dd->gclk);
        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 |= FIELD_PREP(MCHP_PDMC_MR_SINCORDER_MASK, dd->sinc_order);

        maxburst = mchp_pdmc_period_to_maxburst(period_bytes, sample_bytes);
        dd->addr.maxburst = maxburst;
        mr_val |= FIELD_PREP(MCHP_PDMC_MR_CHUNK_MASK, dd->addr.maxburst);
        dev_dbg(comp->dev, "maxburst set to %d\n", dd->addr.maxburst);

        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 void mchp_pdmc_noise_filter_workaround(struct mchp_pdmc *dd)
{
        u32 tmp, steps = 16;

        /*
         * PDMC doesn't wait for microphones' startup time thus the acquisition
         * may start before the microphones are ready leading to poc noises at
         * the beginning of capture. To avoid this, we need to wait 50ms (in
         * normal startup procedure) or 150 ms (worst case after resume from sleep
         * states) after microphones are enabled and then clear the FIFOs (by
         * reading the RHR 16 times) and possible interrupts before continuing.
         * Also, for this to work the DMA needs to be started after interrupts
         * are enabled.
         */
        usleep_range(dd->startup_delay_us, dd->startup_delay_us + 5);

        while (steps--)
                regmap_read(dd->regmap, MCHP_PDMC_RHR, &tmp);

        /* Clear interrupts. */
        regmap_read(dd->regmap, MCHP_PDMC_ISR, &tmp);
}

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_RESUME:
        case SNDRV_PCM_TRIGGER_START:
        case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
                snd_soc_component_update_bits(cpu, MCHP_PDMC_MR,
                                              MCHP_PDMC_MR_PDMCEN_MASK,
                                              dd->pdmcen);

                mchp_pdmc_noise_filter_workaround(dd);

                /* Enable interrupts. */
                regmap_write(dd->regmap, MCHP_PDMC_IER, dd->suspend_irq |
                             MCHP_PDMC_IR_RXOVR | MCHP_PDMC_IR_RXUDR);
                dd->suspend_irq = 0;
                break;
        case SNDRV_PCM_TRIGGER_SUSPEND:
                regmap_read(dd->regmap, MCHP_PDMC_IMR, &dd->suspend_irq);
                fallthrough;
        case SNDRV_PCM_TRIGGER_STOP:
                /* Disable overrun and underrun error interrupts */
                regmap_write(dd->regmap, MCHP_PDMC_IDR, dd->suspend_irq |
                             MCHP_PDMC_IR_RXOVR | MCHP_PDMC_IR_RXUDR);
                fallthrough;
        case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
                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 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_obj(*info);
        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;
}

static const struct snd_soc_dai_ops mchp_pdmc_dai_ops = {
        .probe          = mchp_pdmc_dai_probe,
        .set_fmt        = mchp_pdmc_set_fmt,
        .startup        = mchp_pdmc_startup,
        .hw_params      = mchp_pdmc_hw_params,
        .trigger        = mchp_pdmc_trigger,
        .pcm_new        = &mchp_pdmc_pcm_new,
};

static struct snd_soc_dai_driver mchp_pdmc_dai = {
        .name   = "mchp-pdmc",
        .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,
};

/* PDMC interrupt handler */
static irqreturn_t mchp_pdmc_interrupt(int irq, void *dev_id)
{
        struct mchp_pdmc *dd = 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_RHR:
        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_volatile_reg(struct device *dev, unsigned int reg)
{
        switch (reg) {
        case MCHP_PDMC_ISR:
        case MCHP_PDMC_RHR:
                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,
        .volatile_reg   = mchp_pdmc_volatile_reg,
        .cache_type     = REGCACHE_FLAT,
};

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 microchip,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 microchip,mic-pos: %d",
                        dd->mic_no);
                return -EINVAL;
        }

        dd->mic_no /= 2;

        dev_info(dd->dev, "%d PDM microphones declared\n", dd->mic_no);

        /*
         * by default, we consider the order of microphones in
         * microchip,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;
        }

        dd->startup_delay_us = 150000;
        of_property_read_u32(np, "microchip,startup-delay-us", &dd->startup_delay_us);

        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,
                             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,
        .prepare_slave_config = snd_dmaengine_pcm_prepare_slave_config,
};

static int mchp_pdmc_runtime_suspend(struct device *dev)
{
        struct mchp_pdmc *dd = dev_get_drvdata(dev);

        regcache_cache_only(dd->regmap, true);

        clk_disable_unprepare(dd->gclk);
        clk_disable_unprepare(dd->pclk);

        return 0;
}

static int mchp_pdmc_runtime_resume(struct device *dev)
{
        struct mchp_pdmc *dd = dev_get_drvdata(dev);
        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;
        }
        ret = clk_prepare_enable(dd->gclk);
        if (ret) {
                dev_err(dd->dev,
                        "failed to enable generic clock: %d\n", ret);
                goto disable_pclk;
        }

        regcache_cache_only(dd->regmap, false);
        regcache_mark_dirty(dd->regmap);
        ret = regcache_sync(dd->regmap);
        if (ret) {
                regcache_cache_only(dd->regmap, true);
                clk_disable_unprepare(dd->gclk);
disable_pclk:
                clk_disable_unprepare(dd->pclk);
        }

        return ret;
}

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)
                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), 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);

        pm_runtime_enable(dd->dev);
        if (!pm_runtime_enabled(dd->dev)) {
                ret = mchp_pdmc_runtime_resume(dd->dev);
                if (ret)
                        return ret;
        }

        /* 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);
                goto pm_runtime_suspend;
        }

        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);
                goto pm_runtime_suspend;
        }

        /* 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;

pm_runtime_suspend:
        if (!pm_runtime_status_suspended(dd->dev))
                mchp_pdmc_runtime_suspend(dd->dev);
        pm_runtime_disable(dd->dev);

        return ret;
}

static void mchp_pdmc_remove(struct platform_device *pdev)
{
        struct mchp_pdmc *dd = platform_get_drvdata(pdev);

        atomic_set(&dd->busy_stream, 0);

        if (!pm_runtime_status_suspended(dd->dev))
                mchp_pdmc_runtime_suspend(dd->dev);

        pm_runtime_disable(dd->dev);
}

static const struct of_device_id mchp_pdmc_of_match[] = {
        {
                .compatible = "microchip,sama7g5-pdmc",
        }, {
                /* sentinel */
        }
};
MODULE_DEVICE_TABLE(of, mchp_pdmc_of_match);

static const struct dev_pm_ops mchp_pdmc_pm_ops = {
        SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend, pm_runtime_force_resume)
        RUNTIME_PM_OPS(mchp_pdmc_runtime_suspend, mchp_pdmc_runtime_resume,
                       NULL)
};

static struct platform_driver mchp_pdmc_driver = {
        .driver = {
                .name           = "mchp-pdmc",
                .of_match_table = of_match_ptr(mchp_pdmc_of_match),
                .pm             = pm_ptr(&mchp_pdmc_pm_ops),
        },
        .probe  = mchp_pdmc_probe,
        .remove = mchp_pdmc_remove,
};
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");