// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * atmel_ssc_dai.c  --  ALSA SoC ATMEL SSC Audio Layer Platform driver
 *
 * Copyright (C) 2005 SAN People
 * Copyright (C) 2008 Atmel
 *
 * Author: Sedji Gaouaou <sedji.gaouaou@atmel.com>
 *         ATMEL CORP.
 *
 * Based on at91-ssc.c by
 * Frank Mandarino <fmandarino@endrelia.com>
 * Based on pxa2xx Platform drivers by
 * Liam Girdwood <lrg@slimlogic.co.uk>
 */

#include <linux/init.h>
#include <linux/module.h>
#include <linux/interrupt.h>
#include <linux/device.h>
#include <linux/delay.h>
#include <linux/clk.h>
#include <linux/atmel_pdc.h>

#include <linux/atmel-ssc.h>
#include <sound/core.h>
#include <sound/pcm.h>
#include <sound/pcm_params.h>
#include <sound/initval.h>
#include <sound/soc.h>

#include "atmel-pcm.h"
#include "atmel_ssc_dai.h"


#define NUM_SSC_DEVICES         3

/*
 * SSC PDC registers required by the PCM DMA engine.
 */
static struct atmel_pdc_regs pdc_tx_reg = {
        .xpr            = ATMEL_PDC_TPR,
        .xcr            = ATMEL_PDC_TCR,
        .xnpr           = ATMEL_PDC_TNPR,
        .xncr           = ATMEL_PDC_TNCR,
};

static struct atmel_pdc_regs pdc_rx_reg = {
        .xpr            = ATMEL_PDC_RPR,
        .xcr            = ATMEL_PDC_RCR,
        .xnpr           = ATMEL_PDC_RNPR,
        .xncr           = ATMEL_PDC_RNCR,
};

/*
 * SSC & PDC status bits for transmit and receive.
 */
static struct atmel_ssc_mask ssc_tx_mask = {
        .ssc_enable     = SSC_BIT(CR_TXEN),
        .ssc_disable    = SSC_BIT(CR_TXDIS),
        .ssc_endx       = SSC_BIT(SR_ENDTX),
        .ssc_endbuf     = SSC_BIT(SR_TXBUFE),
        .ssc_error      = SSC_BIT(SR_OVRUN),
        .pdc_enable     = ATMEL_PDC_TXTEN,
        .pdc_disable    = ATMEL_PDC_TXTDIS,
};

static struct atmel_ssc_mask ssc_rx_mask = {
        .ssc_enable     = SSC_BIT(CR_RXEN),
        .ssc_disable    = SSC_BIT(CR_RXDIS),
        .ssc_endx       = SSC_BIT(SR_ENDRX),
        .ssc_endbuf     = SSC_BIT(SR_RXBUFF),
        .ssc_error      = SSC_BIT(SR_OVRUN),
        .pdc_enable     = ATMEL_PDC_RXTEN,
        .pdc_disable    = ATMEL_PDC_RXTDIS,
};


/*
 * DMA parameters.
 */
static struct atmel_pcm_dma_params ssc_dma_params[NUM_SSC_DEVICES][2] = {
        {{
        .name           = "SSC0 PCM out",
        .pdc            = &pdc_tx_reg,
        .mask           = &ssc_tx_mask,
        },
        {
        .name           = "SSC0 PCM in",
        .pdc            = &pdc_rx_reg,
        .mask           = &ssc_rx_mask,
        } },
        {{
        .name           = "SSC1 PCM out",
        .pdc            = &pdc_tx_reg,
        .mask           = &ssc_tx_mask,
        },
        {
        .name           = "SSC1 PCM in",
        .pdc            = &pdc_rx_reg,
        .mask           = &ssc_rx_mask,
        } },
        {{
        .name           = "SSC2 PCM out",
        .pdc            = &pdc_tx_reg,
        .mask           = &ssc_tx_mask,
        },
        {
        .name           = "SSC2 PCM in",
        .pdc            = &pdc_rx_reg,
        .mask           = &ssc_rx_mask,
        } },
};


static struct atmel_ssc_info ssc_info[NUM_SSC_DEVICES] = {
        {
        .name           = "ssc0",
        .dir_mask       = SSC_DIR_MASK_UNUSED,
        .initialized    = 0,
        },
        {
        .name           = "ssc1",
        .dir_mask       = SSC_DIR_MASK_UNUSED,
        .initialized    = 0,
        },
        {
        .name           = "ssc2",
        .dir_mask       = SSC_DIR_MASK_UNUSED,
        .initialized    = 0,
        },
};


/*
 * SSC interrupt handler.  Passes PDC interrupts to the DMA
 * interrupt handler in the PCM driver.
 */
static irqreturn_t atmel_ssc_interrupt(int irq, void *dev_id)
{
        struct atmel_ssc_info *ssc_p = dev_id;
        struct atmel_pcm_dma_params *dma_params;
        u32 ssc_sr;
        u32 ssc_substream_mask;
        int i;

        ssc_sr = (unsigned long)ssc_readl(ssc_p->ssc->regs, SR)
                        & (unsigned long)ssc_readl(ssc_p->ssc->regs, IMR);

        /*
         * Loop through the substreams attached to this SSC.  If
         * a DMA-related interrupt occurred on that substream, call
         * the DMA interrupt handler function, if one has been
         * registered in the dma_params structure by the PCM driver.
         */
        for (i = 0; i < ARRAY_SIZE(ssc_p->dma_params); i++) {
                dma_params = ssc_p->dma_params[i];

                if ((dma_params != NULL) &&
                        (dma_params->dma_intr_handler != NULL)) {
                        ssc_substream_mask = (dma_params->mask->ssc_endx |
                                        dma_params->mask->ssc_endbuf);
                        if (ssc_sr & ssc_substream_mask) {
                                dma_params->dma_intr_handler(ssc_sr,
                                                dma_params->
                                                substream);
                        }
                }
        }

        return IRQ_HANDLED;
}

/*
 * When the bit clock is input, limit the maximum rate according to the
 * Serial Clock Ratio Considerations section from the SSC documentation:
 *
 *   The Transmitter and the Receiver can be programmed to operate
 *   with the clock signals provided on either the TK or RK pins.
 *   This allows the SSC to support many slave-mode data transfers.
 *   In this case, the maximum clock speed allowed on the RK pin is:
 *   - Peripheral clock divided by 2 if Receiver Frame Synchro is input
 *   - Peripheral clock divided by 3 if Receiver Frame Synchro is output
 *   In addition, the maximum clock speed allowed on the TK pin is:
 *   - Peripheral clock divided by 6 if Transmit Frame Synchro is input
 *   - Peripheral clock divided by 2 if Transmit Frame Synchro is output
 *
 * When the bit clock is output, limit the rate according to the
 * SSC divider restrictions.
 */
static int atmel_ssc_hw_rule_rate(struct snd_pcm_hw_params *params,
                                  struct snd_pcm_hw_rule *rule)
{
        struct atmel_ssc_info *ssc_p = rule->private;
        struct ssc_device *ssc = ssc_p->ssc;
        struct snd_interval *i = hw_param_interval(params, rule->var);
        struct snd_interval t;
        struct snd_ratnum r = {
                .den_min = 1,
                .den_max = 4095,
                .den_step = 1,
        };
        unsigned int num = 0, den = 0;
        int frame_size;
        int mck_div = 2;
        int ret;

        frame_size = snd_soc_params_to_frame_size(params);
        if (frame_size < 0)
                return frame_size;

        switch (ssc_p->daifmt & SND_SOC_DAIFMT_MASTER_MASK) {
        case SND_SOC_DAIFMT_CBM_CFS:
                if ((ssc_p->dir_mask & SSC_DIR_MASK_CAPTURE)
                    && ssc->clk_from_rk_pin)
                        /* Receiver Frame Synchro (i.e. capture)
                         * is output (format is _CFS) and the RK pin
                         * is used for input (format is _CBM_).
                         */
                        mck_div = 3;
                break;

        case SND_SOC_DAIFMT_CBM_CFM:
                if ((ssc_p->dir_mask & SSC_DIR_MASK_PLAYBACK)
                    && !ssc->clk_from_rk_pin)
                        /* Transmit Frame Synchro (i.e. playback)
                         * is input (format is _CFM) and the TK pin
                         * is used for input (format _CBM_ but not
                         * using the RK pin).
                         */
                        mck_div = 6;
                break;
        }

        switch (ssc_p->daifmt & SND_SOC_DAIFMT_MASTER_MASK) {
        case SND_SOC_DAIFMT_CBS_CFS:
                r.num = ssc_p->mck_rate / mck_div / frame_size;

                ret = snd_interval_ratnum(i, 1, &r, &num, &den);
                if (ret >= 0 && den && rule->var == SNDRV_PCM_HW_PARAM_RATE) {
                        params->rate_num = num;
                        params->rate_den = den;
                }
                break;

        case SND_SOC_DAIFMT_CBM_CFS:
        case SND_SOC_DAIFMT_CBM_CFM:
                t.min = 8000;
                t.max = ssc_p->mck_rate / mck_div / frame_size;
                t.openmin = t.openmax = 0;
                t.integer = 0;
                ret = snd_interval_refine(i, &t);
                break;

        default:
                ret = -EINVAL;
                break;
        }

        return ret;
}

/*-------------------------------------------------------------------------*\
 * DAI functions
\*-------------------------------------------------------------------------*/
/*
 * Startup.  Only that one substream allowed in each direction.
 */
static int atmel_ssc_startup(struct snd_pcm_substream *substream,
                             struct snd_soc_dai *dai)
{
        struct platform_device *pdev = to_platform_device(dai->dev);
        struct atmel_ssc_info *ssc_p = &ssc_info[pdev->id];
        struct atmel_pcm_dma_params *dma_params;
        int dir, dir_mask;
        int ret;

        pr_debug("atmel_ssc_startup: SSC_SR=0x%x\n",
                ssc_readl(ssc_p->ssc->regs, SR));

        /* Enable PMC peripheral clock for this SSC */
        pr_debug("atmel_ssc_dai: Starting clock\n");
        clk_enable(ssc_p->ssc->clk);
        ssc_p->mck_rate = clk_get_rate(ssc_p->ssc->clk);

        /* Reset the SSC unless initialized to keep it in a clean state */
        if (!ssc_p->initialized)
                ssc_writel(ssc_p->ssc->regs, CR, SSC_BIT(CR_SWRST));

        if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
                dir = 0;
                dir_mask = SSC_DIR_MASK_PLAYBACK;
        } else {
                dir = 1;
                dir_mask = SSC_DIR_MASK_CAPTURE;
        }

        ret = snd_pcm_hw_rule_add(substream->runtime, 0,
                                  SNDRV_PCM_HW_PARAM_RATE,
                                  atmel_ssc_hw_rule_rate,
                                  ssc_p,
                                  SNDRV_PCM_HW_PARAM_FRAME_BITS,
                                  SNDRV_PCM_HW_PARAM_CHANNELS, -1);
        if (ret < 0) {
                dev_err(dai->dev, "Failed to specify rate rule: %d\n", ret);
                return ret;
        }

        dma_params = &ssc_dma_params[pdev->id][dir];
        dma_params->ssc = ssc_p->ssc;
        dma_params->substream = substream;

        ssc_p->dma_params[dir] = dma_params;

        snd_soc_dai_set_dma_data(dai, substream, dma_params);

        if (ssc_p->dir_mask & dir_mask)
                return -EBUSY;

        ssc_p->dir_mask |= dir_mask;

        return 0;
}

/*
 * Shutdown.  Clear DMA parameters and shutdown the SSC if there
 * are no other substreams open.
 */
static void atmel_ssc_shutdown(struct snd_pcm_substream *substream,
                               struct snd_soc_dai *dai)
{
        struct platform_device *pdev = to_platform_device(dai->dev);
        struct atmel_ssc_info *ssc_p = &ssc_info[pdev->id];
        struct atmel_pcm_dma_params *dma_params;
        int dir, dir_mask;

        if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
                dir = 0;
        else
                dir = 1;

        dma_params = ssc_p->dma_params[dir];

        if (dma_params != NULL) {
                dma_params->ssc = NULL;
                dma_params->substream = NULL;
                ssc_p->dma_params[dir] = NULL;
        }

        dir_mask = 1 << dir;

        ssc_p->dir_mask &= ~dir_mask;
        if (!ssc_p->dir_mask) {
                if (ssc_p->initialized) {
                        free_irq(ssc_p->ssc->irq, ssc_p);
                        ssc_p->initialized = 0;
                }

                /* Reset the SSC */
                ssc_writel(ssc_p->ssc->regs, CR, SSC_BIT(CR_SWRST));
                /* Clear the SSC dividers */
                ssc_p->cmr_div = ssc_p->tcmr_period = ssc_p->rcmr_period = 0;
                ssc_p->forced_divider = 0;
        }

        /* Shutdown the SSC clock. */
        pr_debug("atmel_ssc_dai: Stopping clock\n");
        clk_disable(ssc_p->ssc->clk);
}


/*
 * Record the DAI format for use in hw_params().
 */
static int atmel_ssc_set_dai_fmt(struct snd_soc_dai *cpu_dai,
                unsigned int fmt)
{
        struct platform_device *pdev = to_platform_device(cpu_dai->dev);
        struct atmel_ssc_info *ssc_p = &ssc_info[pdev->id];

        ssc_p->daifmt = fmt;
        return 0;
}

/*
 * Record SSC clock dividers for use in hw_params().
 */
static int atmel_ssc_set_dai_clkdiv(struct snd_soc_dai *cpu_dai,
        int div_id, int div)
{
        struct platform_device *pdev = to_platform_device(cpu_dai->dev);
        struct atmel_ssc_info *ssc_p = &ssc_info[pdev->id];

        switch (div_id) {
        case ATMEL_SSC_CMR_DIV:
                /*
                 * The same master clock divider is used for both
                 * transmit and receive, so if a value has already
                 * been set, it must match this value.
                 */
                if (ssc_p->dir_mask !=
                        (SSC_DIR_MASK_PLAYBACK | SSC_DIR_MASK_CAPTURE))
                        ssc_p->cmr_div = div;
                else if (ssc_p->cmr_div == 0)
                        ssc_p->cmr_div = div;
                else
                        if (div != ssc_p->cmr_div)
                                return -EBUSY;
                ssc_p->forced_divider |= BIT(ATMEL_SSC_CMR_DIV);
                break;

        case ATMEL_SSC_TCMR_PERIOD:
                ssc_p->tcmr_period = div;
                ssc_p->forced_divider |= BIT(ATMEL_SSC_TCMR_PERIOD);
                break;

        case ATMEL_SSC_RCMR_PERIOD:
                ssc_p->rcmr_period = div;
                ssc_p->forced_divider |= BIT(ATMEL_SSC_RCMR_PERIOD);
                break;

        default:
                return -EINVAL;
        }

        return 0;
}

/* Is the cpu-dai master of the frame clock? */
static int atmel_ssc_cfs(struct atmel_ssc_info *ssc_p)
{
        switch (ssc_p->daifmt & SND_SOC_DAIFMT_MASTER_MASK) {
        case SND_SOC_DAIFMT_CBM_CFS:
        case SND_SOC_DAIFMT_CBS_CFS:
                return 1;
        }
        return 0;
}

/* Is the cpu-dai master of the bit clock? */
static int atmel_ssc_cbs(struct atmel_ssc_info *ssc_p)
{
        switch (ssc_p->daifmt & SND_SOC_DAIFMT_MASTER_MASK) {
        case SND_SOC_DAIFMT_CBS_CFM:
        case SND_SOC_DAIFMT_CBS_CFS:
                return 1;
        }
        return 0;
}

/*
 * Configure the SSC.
 */
static int atmel_ssc_hw_params(struct snd_pcm_substream *substream,
        struct snd_pcm_hw_params *params,
        struct snd_soc_dai *dai)
{
        struct platform_device *pdev = to_platform_device(dai->dev);
        int id = pdev->id;
        struct atmel_ssc_info *ssc_p = &ssc_info[id];
        struct ssc_device *ssc = ssc_p->ssc;
        struct atmel_pcm_dma_params *dma_params;
        int dir, channels, bits;
        u32 tfmr, rfmr, tcmr, rcmr;
        int ret;
        int fslen, fslen_ext, fs_osync, fs_edge;
        u32 cmr_div;
        u32 tcmr_period;
        u32 rcmr_period;

        /*
         * Currently, there is only one set of dma params for
         * each direction.  If more are added, this code will
         * have to be changed to select the proper set.
         */
        if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
                dir = 0;
        else
                dir = 1;

        /*
         * If the cpu dai should provide BCLK, but noone has provided the
         * divider needed for that to work, fall back to something sensible.
         */
        cmr_div = ssc_p->cmr_div;
        if (!(ssc_p->forced_divider & BIT(ATMEL_SSC_CMR_DIV)) &&
            atmel_ssc_cbs(ssc_p)) {
                int bclk_rate = snd_soc_params_to_bclk(params);

                if (bclk_rate < 0) {
                        dev_err(dai->dev, "unable to calculate cmr_div: %d\n",
                                bclk_rate);
                        return bclk_rate;
                }

                cmr_div = DIV_ROUND_CLOSEST(ssc_p->mck_rate, 2 * bclk_rate);
        }

        /*
         * If the cpu dai should provide LRCLK, but noone has provided the
         * dividers needed for that to work, fall back to something sensible.
         */
        tcmr_period = ssc_p->tcmr_period;
        rcmr_period = ssc_p->rcmr_period;
        if (atmel_ssc_cfs(ssc_p)) {
                int frame_size = snd_soc_params_to_frame_size(params);

                if (frame_size < 0) {
                        dev_err(dai->dev,
                                "unable to calculate tx/rx cmr_period: %d\n",
                                frame_size);
                        return frame_size;
                }

                if (!(ssc_p->forced_divider & BIT(ATMEL_SSC_TCMR_PERIOD)))
                        tcmr_period = frame_size / 2 - 1;
                if (!(ssc_p->forced_divider & BIT(ATMEL_SSC_RCMR_PERIOD)))
                        rcmr_period = frame_size / 2 - 1;
        }

        dma_params = ssc_p->dma_params[dir];

        channels = params_channels(params);

        /*
         * Determine sample size in bits and the PDC increment.
         */
        switch (params_format(params)) {
        case SNDRV_PCM_FORMAT_S8:
                bits = 8;
                dma_params->pdc_xfer_size = 1;
                break;
        case SNDRV_PCM_FORMAT_S16_LE:
                bits = 16;
                dma_params->pdc_xfer_size = 2;
                break;
        case SNDRV_PCM_FORMAT_S24_LE:
                bits = 24;
                dma_params->pdc_xfer_size = 4;
                break;
        case SNDRV_PCM_FORMAT_S32_LE:
                bits = 32;
                dma_params->pdc_xfer_size = 4;
                break;
        default:
                printk(KERN_WARNING "atmel_ssc_dai: unsupported PCM format");
                return -EINVAL;
        }

        /*
         * Compute SSC register settings.
         */

        fslen_ext = (bits - 1) / 16;
        fslen = (bits - 1) % 16;

        switch (ssc_p->daifmt & SND_SOC_DAIFMT_FORMAT_MASK) {

        case SND_SOC_DAIFMT_LEFT_J:
                fs_osync = SSC_FSOS_POSITIVE;
                fs_edge = SSC_START_RISING_RF;

                rcmr =    SSC_BF(RCMR_STTDLY, 0);
                tcmr =    SSC_BF(TCMR_STTDLY, 0);

                break;

        case SND_SOC_DAIFMT_I2S:
                fs_osync = SSC_FSOS_NEGATIVE;
                fs_edge = SSC_START_FALLING_RF;

                rcmr =    SSC_BF(RCMR_STTDLY, 1);
                tcmr =    SSC_BF(TCMR_STTDLY, 1);

                break;

        case SND_SOC_DAIFMT_DSP_A:
                /*
                 * DSP/PCM Mode A format
                 *
                 * Data is transferred on first BCLK after LRC pulse rising
                 * edge.If stereo, the right channel data is contiguous with
                 * the left channel data.
                 */
                fs_osync = SSC_FSOS_POSITIVE;
                fs_edge = SSC_START_RISING_RF;
                fslen = fslen_ext = 0;

                rcmr =    SSC_BF(RCMR_STTDLY, 1);
                tcmr =    SSC_BF(TCMR_STTDLY, 1);

                break;

        default:
                printk(KERN_WARNING "atmel_ssc_dai: unsupported DAI format 0x%x\n",
                        ssc_p->daifmt);
                return -EINVAL;
        }

        if (!atmel_ssc_cfs(ssc_p)) {
                fslen = fslen_ext = 0;
                rcmr_period = tcmr_period = 0;
                fs_osync = SSC_FSOS_NONE;
        }

        rcmr |=   SSC_BF(RCMR_START, fs_edge);
        tcmr |=   SSC_BF(TCMR_START, fs_edge);

        if (atmel_ssc_cbs(ssc_p)) {
                /*
                 * SSC provides BCLK
                 *
                 * The SSC transmit and receive clocks are generated from the
                 * MCK divider, and the BCLK signal is output
                 * on the SSC TK line.
                 */
                rcmr |=   SSC_BF(RCMR_CKS, SSC_CKS_DIV)
                        | SSC_BF(RCMR_CKO, SSC_CKO_NONE);

                tcmr |=   SSC_BF(TCMR_CKS, SSC_CKS_DIV)
                        | SSC_BF(TCMR_CKO, SSC_CKO_CONTINUOUS);
        } else {
                rcmr |=   SSC_BF(RCMR_CKS, ssc->clk_from_rk_pin ?
                                        SSC_CKS_PIN : SSC_CKS_CLOCK)
                        | SSC_BF(RCMR_CKO, SSC_CKO_NONE);

                tcmr |=   SSC_BF(TCMR_CKS, ssc->clk_from_rk_pin ?
                                        SSC_CKS_CLOCK : SSC_CKS_PIN)
                        | SSC_BF(TCMR_CKO, SSC_CKO_NONE);
        }

        rcmr |=   SSC_BF(RCMR_PERIOD, rcmr_period)
                | SSC_BF(RCMR_CKI, SSC_CKI_RISING);

        tcmr |=   SSC_BF(TCMR_PERIOD, tcmr_period)
                | SSC_BF(TCMR_CKI, SSC_CKI_FALLING);

        rfmr =    SSC_BF(RFMR_FSLEN_EXT, fslen_ext)
                | SSC_BF(RFMR_FSEDGE, SSC_FSEDGE_POSITIVE)
                | SSC_BF(RFMR_FSOS, fs_osync)
                | SSC_BF(RFMR_FSLEN, fslen)
                | SSC_BF(RFMR_DATNB, (channels - 1))
                | SSC_BIT(RFMR_MSBF)
                | SSC_BF(RFMR_LOOP, 0)
                | SSC_BF(RFMR_DATLEN, (bits - 1));

        tfmr =    SSC_BF(TFMR_FSLEN_EXT, fslen_ext)
                | SSC_BF(TFMR_FSEDGE, SSC_FSEDGE_POSITIVE)
                | SSC_BF(TFMR_FSDEN, 0)
                | SSC_BF(TFMR_FSOS, fs_osync)
                | SSC_BF(TFMR_FSLEN, fslen)
                | SSC_BF(TFMR_DATNB, (channels - 1))
                | SSC_BIT(TFMR_MSBF)
                | SSC_BF(TFMR_DATDEF, 0)
                | SSC_BF(TFMR_DATLEN, (bits - 1));

        if (fslen_ext && !ssc->pdata->has_fslen_ext) {
                dev_err(dai->dev, "sample size %d is too large for SSC device\n",
                        bits);
                return -EINVAL;
        }

        pr_debug("atmel_ssc_hw_params: "
                        "RCMR=%08x RFMR=%08x TCMR=%08x TFMR=%08x\n",
                        rcmr, rfmr, tcmr, tfmr);

        if (!ssc_p->initialized) {
                if (!ssc_p->ssc->pdata->use_dma) {
                        ssc_writel(ssc_p->ssc->regs, PDC_RPR, 0);
                        ssc_writel(ssc_p->ssc->regs, PDC_RCR, 0);
                        ssc_writel(ssc_p->ssc->regs, PDC_RNPR, 0);
                        ssc_writel(ssc_p->ssc->regs, PDC_RNCR, 0);

                        ssc_writel(ssc_p->ssc->regs, PDC_TPR, 0);
                        ssc_writel(ssc_p->ssc->regs, PDC_TCR, 0);
                        ssc_writel(ssc_p->ssc->regs, PDC_TNPR, 0);
                        ssc_writel(ssc_p->ssc->regs, PDC_TNCR, 0);
                }

                ret = request_irq(ssc_p->ssc->irq, atmel_ssc_interrupt, 0,
                                ssc_p->name, ssc_p);
                if (ret < 0) {
                        printk(KERN_WARNING
                                        "atmel_ssc_dai: request_irq failure\n");
                        pr_debug("Atmel_ssc_dai: Stopping clock\n");
                        clk_disable(ssc_p->ssc->clk);
                        return ret;
                }

                ssc_p->initialized = 1;
        }

        /* set SSC clock mode register */
        ssc_writel(ssc_p->ssc->regs, CMR, cmr_div);

        /* set receive clock mode and format */
        ssc_writel(ssc_p->ssc->regs, RCMR, rcmr);
        ssc_writel(ssc_p->ssc->regs, RFMR, rfmr);

        /* set transmit clock mode and format */
        ssc_writel(ssc_p->ssc->regs, TCMR, tcmr);
        ssc_writel(ssc_p->ssc->regs, TFMR, tfmr);

        pr_debug("atmel_ssc_dai,hw_params: SSC initialized\n");
        return 0;
}


static int atmel_ssc_prepare(struct snd_pcm_substream *substream,
                             struct snd_soc_dai *dai)
{
        struct platform_device *pdev = to_platform_device(dai->dev);
        struct atmel_ssc_info *ssc_p = &ssc_info[pdev->id];
        struct atmel_pcm_dma_params *dma_params;
        int dir;

        if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
                dir = 0;
        else
                dir = 1;

        dma_params = ssc_p->dma_params[dir];

        ssc_writel(ssc_p->ssc->regs, CR, dma_params->mask->ssc_disable);
        ssc_writel(ssc_p->ssc->regs, IDR, dma_params->mask->ssc_error);

        pr_debug("%s enabled SSC_SR=0x%08x\n",
                        dir ? "receive" : "transmit",
                        ssc_readl(ssc_p->ssc->regs, SR));
        return 0;
}

static int atmel_ssc_trigger(struct snd_pcm_substream *substream,
                             int cmd, struct snd_soc_dai *dai)
{
        struct platform_device *pdev = to_platform_device(dai->dev);
        struct atmel_ssc_info *ssc_p = &ssc_info[pdev->id];
        struct atmel_pcm_dma_params *dma_params;
        int dir;

        if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
                dir = 0;
        else
                dir = 1;

        dma_params = ssc_p->dma_params[dir];

        switch (cmd) {
        case SNDRV_PCM_TRIGGER_START:
        case SNDRV_PCM_TRIGGER_RESUME:
        case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
                ssc_writel(ssc_p->ssc->regs, CR, dma_params->mask->ssc_enable);
                break;
        default:
                ssc_writel(ssc_p->ssc->regs, CR, dma_params->mask->ssc_disable);
                break;
        }

        return 0;
}

#ifdef CONFIG_PM
static int atmel_ssc_suspend(struct snd_soc_component *component)
{
        struct atmel_ssc_info *ssc_p;
        struct platform_device *pdev = to_platform_device(component->dev);

        if (!snd_soc_component_active(component))
                return 0;

        ssc_p = &ssc_info[pdev->id];

        /* Save the status register before disabling transmit and receive */
        ssc_p->ssc_state.ssc_sr = ssc_readl(ssc_p->ssc->regs, SR);
        ssc_writel(ssc_p->ssc->regs, CR, SSC_BIT(CR_TXDIS) | SSC_BIT(CR_RXDIS));

        /* Save the current interrupt mask, then disable unmasked interrupts */
        ssc_p->ssc_state.ssc_imr = ssc_readl(ssc_p->ssc->regs, IMR);
        ssc_writel(ssc_p->ssc->regs, IDR, ssc_p->ssc_state.ssc_imr);

        ssc_p->ssc_state.ssc_cmr = ssc_readl(ssc_p->ssc->regs, CMR);
        ssc_p->ssc_state.ssc_rcmr = ssc_readl(ssc_p->ssc->regs, RCMR);
        ssc_p->ssc_state.ssc_rfmr = ssc_readl(ssc_p->ssc->regs, RFMR);
        ssc_p->ssc_state.ssc_tcmr = ssc_readl(ssc_p->ssc->regs, TCMR);
        ssc_p->ssc_state.ssc_tfmr = ssc_readl(ssc_p->ssc->regs, TFMR);

        return 0;
}

static int atmel_ssc_resume(struct snd_soc_component *component)
{
        struct atmel_ssc_info *ssc_p;
        struct platform_device *pdev = to_platform_device(component->dev);
        u32 cr;

        if (!snd_soc_component_active(component))
                return 0;

        ssc_p = &ssc_info[pdev->id];

        /* restore SSC register settings */
        ssc_writel(ssc_p->ssc->regs, TFMR, ssc_p->ssc_state.ssc_tfmr);
        ssc_writel(ssc_p->ssc->regs, TCMR, ssc_p->ssc_state.ssc_tcmr);
        ssc_writel(ssc_p->ssc->regs, RFMR, ssc_p->ssc_state.ssc_rfmr);
        ssc_writel(ssc_p->ssc->regs, RCMR, ssc_p->ssc_state.ssc_rcmr);
        ssc_writel(ssc_p->ssc->regs, CMR, ssc_p->ssc_state.ssc_cmr);

        /* re-enable interrupts */
        ssc_writel(ssc_p->ssc->regs, IER, ssc_p->ssc_state.ssc_imr);

        /* Re-enable receive and transmit as appropriate */
        cr = 0;
        cr |=
            (ssc_p->ssc_state.ssc_sr & SSC_BIT(SR_RXEN)) ? SSC_BIT(CR_RXEN) : 0;
        cr |=
            (ssc_p->ssc_state.ssc_sr & SSC_BIT(SR_TXEN)) ? SSC_BIT(CR_TXEN) : 0;
        ssc_writel(ssc_p->ssc->regs, CR, cr);

        return 0;
}
#else /* CONFIG_PM */
#  define atmel_ssc_suspend     NULL
#  define atmel_ssc_resume      NULL
#endif /* CONFIG_PM */

#define ATMEL_SSC_FORMATS (SNDRV_PCM_FMTBIT_S8     | SNDRV_PCM_FMTBIT_S16_LE |\
                          SNDRV_PCM_FMTBIT_S24_LE | SNDRV_PCM_FMTBIT_S32_LE)

static const struct snd_soc_dai_ops atmel_ssc_dai_ops = {
        .startup        = atmel_ssc_startup,
        .shutdown       = atmel_ssc_shutdown,
        .prepare        = atmel_ssc_prepare,
        .trigger        = atmel_ssc_trigger,
        .hw_params      = atmel_ssc_hw_params,
        .set_fmt        = atmel_ssc_set_dai_fmt,
        .set_clkdiv     = atmel_ssc_set_dai_clkdiv,
};

static struct snd_soc_dai_driver atmel_ssc_dai = {
                .playback = {
                        .channels_min = 1,
                        .channels_max = 2,
                        .rates = SNDRV_PCM_RATE_CONTINUOUS,
                        .rate_min = 8000,
                        .rate_max = 384000,
                        .formats = ATMEL_SSC_FORMATS,},
                .capture = {
                        .channels_min = 1,
                        .channels_max = 2,
                        .rates = SNDRV_PCM_RATE_CONTINUOUS,
                        .rate_min = 8000,
                        .rate_max = 384000,
                        .formats = ATMEL_SSC_FORMATS,},
                .ops = &atmel_ssc_dai_ops,
};

static const struct snd_soc_component_driver atmel_ssc_component = {
        .name           = "atmel-ssc",
        .suspend        = atmel_ssc_suspend,
        .resume         = atmel_ssc_resume,
};

static int asoc_ssc_init(struct device *dev)
{
        struct ssc_device *ssc = dev_get_drvdata(dev);
        int ret;

        ret = devm_snd_soc_register_component(dev, &atmel_ssc_component,
                                         &atmel_ssc_dai, 1);
        if (ret) {
                dev_err(dev, "Could not register DAI: %d\n", ret);
                return ret;
        }

        if (ssc->pdata->use_dma)
                ret = atmel_pcm_dma_platform_register(dev);
        else
                ret = atmel_pcm_pdc_platform_register(dev);

        if (ret) {
                dev_err(dev, "Could not register PCM: %d\n", ret);
                return ret;
        }

        return 0;
}

/**
 * atmel_ssc_set_audio - Allocate the specified SSC for audio use.
 * @ssc_id: SSD ID in [0, NUM_SSC_DEVICES[
 */
int atmel_ssc_set_audio(int ssc_id)
{
        struct ssc_device *ssc;
        int ret;

        /* If we can grab the SSC briefly to parent the DAI device off it */
        ssc = ssc_request(ssc_id);
        if (IS_ERR(ssc)) {
                pr_err("Unable to parent ASoC SSC DAI on SSC: %ld\n",
                        PTR_ERR(ssc));
                return PTR_ERR(ssc);
        } else {
                ssc_info[ssc_id].ssc = ssc;
        }

        ret = asoc_ssc_init(&ssc->pdev->dev);

        return ret;
}
EXPORT_SYMBOL_GPL(atmel_ssc_set_audio);

void atmel_ssc_put_audio(int ssc_id)
{
        struct ssc_device *ssc = ssc_info[ssc_id].ssc;

        ssc_free(ssc);
}
EXPORT_SYMBOL_GPL(atmel_ssc_put_audio);

/* Module information */
MODULE_AUTHOR("Sedji Gaouaou, sedji.gaouaou@atmel.com, www.atmel.com");
MODULE_DESCRIPTION("ATMEL SSC ASoC Interface");
MODULE_LICENSE("GPL");