// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Copyright 2011 Freescale Semiconductor, Inc.
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/dma-mapping.h>
#include <linux/clk.h>
#include <linux/clk-provider.h>
#include <linux/delay.h>
#include <linux/io.h>
#include <linux/time.h>
#include <sound/core.h>
#include <sound/pcm.h>
#include <sound/pcm_params.h>
#include <sound/soc.h>

#include "mxs-saif.h"

#define MXS_SET_ADDR    0x4
#define MXS_CLR_ADDR    0x8

#define MXS_SAIF_BUSY_TIMEOUT_US 10000

static struct mxs_saif *mxs_saif[2];

/*
 * Since SAIF may work on EXTMASTER mode, IOW, it's working BITCLK&LRCLK
 * is provided by other SAIF, we provide a interface here to get its master
 * from its master_id.
 * Note that the master could be itself.
 */
static inline struct mxs_saif *mxs_saif_get_master(struct mxs_saif *saif)
{
        return mxs_saif[saif->master_id];
}

static int __mxs_saif_put_mclk(struct mxs_saif *saif)
{
        u32 stat;
        int ret;

        ret = readx_poll_timeout(__raw_readl, saif->base + SAIF_STAT, stat,
                                 (stat & BM_SAIF_STAT_BUSY) == 0,
                                 MXS_SAIF_BUSY_TIMEOUT_US,
                                 USEC_PER_SEC);
        if (ret) {
                dev_err(saif->dev, "error: busy\n");
                return -EBUSY;
        }

        /* disable MCLK output */
        __raw_writel(BM_SAIF_CTRL_CLKGATE,
                saif->base + SAIF_CTRL + MXS_SET_ADDR);
        __raw_writel(BM_SAIF_CTRL_RUN,
                saif->base + SAIF_CTRL + MXS_CLR_ADDR);

        saif->mclk_in_use = 0;

        return 0;
}

static int __mxs_saif_get_mclk(struct mxs_saif *saif)
{
        u32 stat;
        struct mxs_saif *master_saif;

        if (!saif)
                return -EINVAL;

        /* Clear Reset */
        __raw_writel(BM_SAIF_CTRL_SFTRST,
                saif->base + SAIF_CTRL + MXS_CLR_ADDR);

        /* FIXME: need clear clk gate for register r/w */
        __raw_writel(BM_SAIF_CTRL_CLKGATE,
                saif->base + SAIF_CTRL + MXS_CLR_ADDR);

        master_saif = mxs_saif_get_master(saif);
        if (saif != master_saif) {
                dev_err(saif->dev, "can not get mclk from a non-master saif\n");
                return -EINVAL;
        }

        stat = __raw_readl(saif->base + SAIF_STAT);
        if (stat & BM_SAIF_STAT_BUSY) {
                dev_err(saif->dev, "error: busy\n");
                return -EBUSY;
        }

        saif->mclk_in_use = 1;

        return 0;
}

/*
 * SAIF is a little different with other normal SOC DAIs on clock using.
 *
 * For MXS, two SAIF modules are instantiated on-chip.
 * Each SAIF has a set of clock pins and can be operating in master
 * mode simultaneously if they are connected to different off-chip codecs.
 * Also, one of the two SAIFs can master or drive the clock pins while the
 * other SAIF, in slave mode, receives clocking from the master SAIF.
 * This also means that both SAIFs must operate at the same sample rate.
 *
 * We abstract this as each saif has a master, the master could be
 * itself or other saifs. In the generic saif driver, saif does not need
 * to know the different clkmux. Saif only needs to know who is its master
 * and operating its master to generate the proper clock rate for it.
 * The master id is provided in mach-specific layer according to different
 * clkmux setting.
 */

static int mxs_saif_set_dai_sysclk(struct snd_soc_dai *cpu_dai,
                        int clk_id, unsigned int freq, int dir)
{
        struct mxs_saif *saif = snd_soc_dai_get_drvdata(cpu_dai);
        int ret;

        switch (clk_id) {
        case MXS_SAIF_MCLK:
                saif->mclk = freq;
                break;
        default:
                return -EINVAL;
        }

        if (!saif->mclk_in_use && freq) {
                ret = __mxs_saif_get_mclk(saif);
                if (ret)
                        return ret;

                /* enable MCLK output */
                __raw_writel(BM_SAIF_CTRL_RUN,
                saif->base + SAIF_CTRL + MXS_SET_ADDR);
        } else if (saif->mclk_in_use && freq == 0) {
                ret = __mxs_saif_put_mclk(saif);
                if (ret)
                        return ret;
        }

        return 0;
}

/*
 * Set SAIF clock and MCLK
 */
static int mxs_saif_set_clk(struct mxs_saif *saif,
                                  unsigned int mclk,
                                  unsigned int rate)
{
        u32 scr;
        int ret;
        struct mxs_saif *master_saif;

        dev_dbg(saif->dev, "mclk %d rate %d\n", mclk, rate);

        /* Set master saif to generate proper clock */
        master_saif = mxs_saif_get_master(saif);
        if (!master_saif)
                return -EINVAL;

        dev_dbg(saif->dev, "master saif%d\n", master_saif->id);

        /* Checking if can playback and capture simutaneously */
        if (master_saif->ongoing && rate != master_saif->cur_rate) {
                dev_err(saif->dev,
                        "can not change clock, master saif%d(rate %d) is ongoing\n",
                        master_saif->id, master_saif->cur_rate);
                return -EINVAL;
        }

        scr = __raw_readl(master_saif->base + SAIF_CTRL);
        scr &= ~BM_SAIF_CTRL_BITCLK_MULT_RATE;
        scr &= ~BM_SAIF_CTRL_BITCLK_BASE_RATE;

        /*
         * Set SAIF clock
         *
         * The SAIF clock should be either 384*fs or 512*fs.
         * If MCLK is used, the SAIF clk ratio needs to match mclk ratio.
         *  For 256x, 128x, 64x, and 32x sub-rates, set saif clk as 512*fs.
         *  For 192x, 96x, and 48x sub-rates, set saif clk as 384*fs.
         *
         * If MCLK is not used, we just set saif clk to 512*fs.
         */
        ret = clk_prepare_enable(master_saif->clk);
        if (ret)
                return ret;

        if (master_saif->mclk_in_use) {
                switch (mclk / rate) {
                case 32:
                case 64:
                case 128:
                case 256:
                case 512:
                        scr &= ~BM_SAIF_CTRL_BITCLK_BASE_RATE;
                        ret = clk_set_rate(master_saif->clk, 512 * rate);
                        break;
                case 48:
                case 96:
                case 192:
                case 384:
                        scr |= BM_SAIF_CTRL_BITCLK_BASE_RATE;
                        ret = clk_set_rate(master_saif->clk, 384 * rate);
                        break;
                default:
                        /* SAIF MCLK should be a sub-rate of 512x or 384x */
                        clk_disable_unprepare(master_saif->clk);
                        return -EINVAL;
                }
        } else {
                ret = clk_set_rate(master_saif->clk, 512 * rate);
                scr &= ~BM_SAIF_CTRL_BITCLK_BASE_RATE;
        }

        clk_disable_unprepare(master_saif->clk);

        if (ret)
                return ret;

        master_saif->cur_rate = rate;

        if (!master_saif->mclk_in_use) {
                __raw_writel(scr, master_saif->base + SAIF_CTRL);
                return 0;
        }

        /*
         * Program the over-sample rate for MCLK output
         *
         * The available MCLK range is 32x, 48x... 512x. The rate
         * could be from 8kHz to 192kH.
         */
        switch (mclk / rate) {
        case 32:
                scr |= BF_SAIF_CTRL_BITCLK_MULT_RATE(4);
                break;
        case 64:
                scr |= BF_SAIF_CTRL_BITCLK_MULT_RATE(3);
                break;
        case 128:
                scr |= BF_SAIF_CTRL_BITCLK_MULT_RATE(2);
                break;
        case 256:
                scr |= BF_SAIF_CTRL_BITCLK_MULT_RATE(1);
                break;
        case 512:
                scr |= BF_SAIF_CTRL_BITCLK_MULT_RATE(0);
                break;
        case 48:
                scr |= BF_SAIF_CTRL_BITCLK_MULT_RATE(3);
                break;
        case 96:
                scr |= BF_SAIF_CTRL_BITCLK_MULT_RATE(2);
                break;
        case 192:
                scr |= BF_SAIF_CTRL_BITCLK_MULT_RATE(1);
                break;
        case 384:
                scr |= BF_SAIF_CTRL_BITCLK_MULT_RATE(0);
                break;
        default:
                return -EINVAL;
        }

        __raw_writel(scr, master_saif->base + SAIF_CTRL);

        return 0;
}

/*
 * Put and disable MCLK.
 */
int mxs_saif_put_mclk(unsigned int saif_id)
{
        struct mxs_saif *saif = mxs_saif[saif_id];
        u32 stat;

        if (!saif)
                return -EINVAL;

        stat = __raw_readl(saif->base + SAIF_STAT);
        if (stat & BM_SAIF_STAT_BUSY) {
                dev_err(saif->dev, "error: busy\n");
                return -EBUSY;
        }

        clk_disable_unprepare(saif->clk);

        /* disable MCLK output */
        __raw_writel(BM_SAIF_CTRL_CLKGATE,
                saif->base + SAIF_CTRL + MXS_SET_ADDR);
        __raw_writel(BM_SAIF_CTRL_RUN,
                saif->base + SAIF_CTRL + MXS_CLR_ADDR);

        saif->mclk_in_use = 0;
        return 0;
}
EXPORT_SYMBOL_GPL(mxs_saif_put_mclk);

/*
 * Get MCLK and set clock rate, then enable it
 *
 * This interface is used for codecs who are using MCLK provided
 * by saif.
 */
int mxs_saif_get_mclk(unsigned int saif_id, unsigned int mclk,
                                        unsigned int rate)
{
        struct mxs_saif *saif = mxs_saif[saif_id];
        int ret;

        if (!saif)
                return -EINVAL;

        ret = __mxs_saif_get_mclk(saif);
        if (ret)
                return ret;

        ret = mxs_saif_set_clk(saif, mclk, rate);
        if (ret)
                return ret;

        ret = clk_prepare_enable(saif->clk);
        if (ret)
                return ret;

        /* enable MCLK output */
        __raw_writel(BM_SAIF_CTRL_RUN,
                saif->base + SAIF_CTRL + MXS_SET_ADDR);

        return 0;
}
EXPORT_SYMBOL_GPL(mxs_saif_get_mclk);

/*
 * SAIF DAI format configuration.
 * Should only be called when port is inactive.
 */
static int mxs_saif_set_dai_fmt(struct snd_soc_dai *cpu_dai, unsigned int fmt)
{
        u32 scr, stat;
        u32 scr0;
        struct mxs_saif *saif = snd_soc_dai_get_drvdata(cpu_dai);

        stat = __raw_readl(saif->base + SAIF_STAT);
        if (stat & BM_SAIF_STAT_BUSY) {
                dev_err(cpu_dai->dev, "error: busy\n");
                return -EBUSY;
        }

        /* If SAIF1 is configured as slave, the clk gate needs to be cleared
         * before the register can be written.
         */
        if (saif->id != saif->master_id) {
                __raw_writel(BM_SAIF_CTRL_SFTRST,
                        saif->base + SAIF_CTRL + MXS_CLR_ADDR);
                __raw_writel(BM_SAIF_CTRL_CLKGATE,
                        saif->base + SAIF_CTRL + MXS_CLR_ADDR);
        }

        scr0 = __raw_readl(saif->base + SAIF_CTRL);
        scr0 = scr0 & ~BM_SAIF_CTRL_BITCLK_EDGE & ~BM_SAIF_CTRL_LRCLK_POLARITY \
                & ~BM_SAIF_CTRL_JUSTIFY & ~BM_SAIF_CTRL_DELAY;
        scr = 0;

        /* DAI mode */
        switch (fmt & SND_SOC_DAIFMT_FORMAT_MASK) {
        case SND_SOC_DAIFMT_I2S:
                /* data frame low 1clk before data */
                scr |= BM_SAIF_CTRL_DELAY;
                scr &= ~BM_SAIF_CTRL_LRCLK_POLARITY;
                break;
        case SND_SOC_DAIFMT_LEFT_J:
                /* data frame high with data */
                scr &= ~BM_SAIF_CTRL_DELAY;
                scr &= ~BM_SAIF_CTRL_LRCLK_POLARITY;
                scr &= ~BM_SAIF_CTRL_JUSTIFY;
                break;
        default:
                return -EINVAL;
        }

        /* DAI clock inversion */
        switch (fmt & SND_SOC_DAIFMT_INV_MASK) {
        case SND_SOC_DAIFMT_IB_IF:
                scr |= BM_SAIF_CTRL_BITCLK_EDGE;
                scr |= BM_SAIF_CTRL_LRCLK_POLARITY;
                break;
        case SND_SOC_DAIFMT_IB_NF:
                scr |= BM_SAIF_CTRL_BITCLK_EDGE;
                scr &= ~BM_SAIF_CTRL_LRCLK_POLARITY;
                break;
        case SND_SOC_DAIFMT_NB_IF:
                scr &= ~BM_SAIF_CTRL_BITCLK_EDGE;
                scr |= BM_SAIF_CTRL_LRCLK_POLARITY;
                break;
        case SND_SOC_DAIFMT_NB_NF:
                scr &= ~BM_SAIF_CTRL_BITCLK_EDGE;
                scr &= ~BM_SAIF_CTRL_LRCLK_POLARITY;
                break;
        }

        /*
         * Note: We simply just support master mode since SAIF TX can only
         * work as master.
         * Here the master is relative to codec side.
         * Saif internally could be slave when working on EXTMASTER mode.
         * We just hide this to machine driver.
         */
        switch (fmt & SND_SOC_DAIFMT_CLOCK_PROVIDER_MASK) {
        case SND_SOC_DAIFMT_BP_FP:
                if (saif->id == saif->master_id)
                        scr &= ~BM_SAIF_CTRL_SLAVE_MODE;
                else
                        scr |= BM_SAIF_CTRL_SLAVE_MODE;

                __raw_writel(scr | scr0, saif->base + SAIF_CTRL);
                break;
        default:
                return -EINVAL;
        }

        return 0;
}

static int mxs_saif_startup(struct snd_pcm_substream *substream,
                           struct snd_soc_dai *cpu_dai)
{
        struct mxs_saif *saif = snd_soc_dai_get_drvdata(cpu_dai);
        int ret;

        /* clear error status to 0 for each re-open */
        saif->fifo_underrun = 0;
        saif->fifo_overrun = 0;

        /* Clear Reset for normal operations */
        __raw_writel(BM_SAIF_CTRL_SFTRST,
                saif->base + SAIF_CTRL + MXS_CLR_ADDR);

        /* clear clock gate */
        __raw_writel(BM_SAIF_CTRL_CLKGATE,
                saif->base + SAIF_CTRL + MXS_CLR_ADDR);

        ret = clk_prepare(saif->clk);
        if (ret)
                return ret;

        return 0;
}

static void mxs_saif_shutdown(struct snd_pcm_substream *substream,
                              struct snd_soc_dai *cpu_dai)
{
        struct mxs_saif *saif = snd_soc_dai_get_drvdata(cpu_dai);

        clk_unprepare(saif->clk);
}

/*
 * Should only be called when port is inactive.
 * although can be called multiple times by upper layers.
 */
static int mxs_saif_hw_params(struct snd_pcm_substream *substream,
                             struct snd_pcm_hw_params *params,
                             struct snd_soc_dai *cpu_dai)
{
        struct mxs_saif *saif = snd_soc_dai_get_drvdata(cpu_dai);
        struct mxs_saif *master_saif;
        u32 scr, stat;
        int ret;

        master_saif = mxs_saif_get_master(saif);
        if (!master_saif)
                return -EINVAL;

        /* mclk should already be set */
        if (!saif->mclk && saif->mclk_in_use) {
                dev_err(cpu_dai->dev, "set mclk first\n");
                return -EINVAL;
        }

        stat = __raw_readl(saif->base + SAIF_STAT);
        if (!saif->mclk_in_use && (stat & BM_SAIF_STAT_BUSY)) {
                dev_err(cpu_dai->dev, "error: busy\n");
                return -EBUSY;
        }

        /*
         * Set saif clk based on sample rate.
         * If mclk is used, we also set mclk, if not, saif->mclk is
         * default 0, means not used.
         */
        ret = mxs_saif_set_clk(saif, saif->mclk, params_rate(params));
        if (ret) {
                dev_err(cpu_dai->dev, "unable to get proper clk\n");
                return ret;
        }

        if (saif != master_saif) {
                /*
                * Set an initial clock rate for the saif internal logic to work
                * properly. This is important when working in EXTMASTER mode
                * that uses the other saif's BITCLK&LRCLK but it still needs a
                * basic clock which should be fast enough for the internal
                * logic.
                */
                ret = clk_enable(saif->clk);
                if (ret)
                        return ret;

                ret = clk_set_rate(saif->clk, 24000000);
                clk_disable(saif->clk);
                if (ret)
                        return ret;

                ret = clk_prepare(master_saif->clk);
                if (ret)
                        return ret;
        }

        scr = __raw_readl(saif->base + SAIF_CTRL);

        scr &= ~BM_SAIF_CTRL_WORD_LENGTH;
        scr &= ~BM_SAIF_CTRL_BITCLK_48XFS_ENABLE;
        switch (params_format(params)) {
        case SNDRV_PCM_FORMAT_S16_LE:
                scr |= BF_SAIF_CTRL_WORD_LENGTH(0);
                break;
        case SNDRV_PCM_FORMAT_S20_3LE:
                scr |= BF_SAIF_CTRL_WORD_LENGTH(4);
                scr |= BM_SAIF_CTRL_BITCLK_48XFS_ENABLE;
                break;
        case SNDRV_PCM_FORMAT_S24_LE:
                scr |= BF_SAIF_CTRL_WORD_LENGTH(8);
                scr |= BM_SAIF_CTRL_BITCLK_48XFS_ENABLE;
                break;
        default:
                return -EINVAL;
        }

        /* Tx/Rx config */
        if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
                /* enable TX mode */
                scr &= ~BM_SAIF_CTRL_READ_MODE;
        } else {
                /* enable RX mode */
                scr |= BM_SAIF_CTRL_READ_MODE;
        }

        __raw_writel(scr, saif->base + SAIF_CTRL);
        return 0;
}

static int mxs_saif_prepare(struct snd_pcm_substream *substream,
                           struct snd_soc_dai *cpu_dai)
{
        struct mxs_saif *saif = snd_soc_dai_get_drvdata(cpu_dai);

        /* enable FIFO error irqs */
        __raw_writel(BM_SAIF_CTRL_FIFO_ERROR_IRQ_EN,
                saif->base + SAIF_CTRL + MXS_SET_ADDR);

        return 0;
}

static int mxs_saif_trigger(struct snd_pcm_substream *substream, int cmd,
                                struct snd_soc_dai *cpu_dai)
{
        struct mxs_saif *saif = snd_soc_dai_get_drvdata(cpu_dai);
        struct mxs_saif *master_saif;
        u32 delay;
        int ret;

        master_saif = mxs_saif_get_master(saif);
        if (!master_saif)
                return -EINVAL;

        switch (cmd) {
        case SNDRV_PCM_TRIGGER_START:
        case SNDRV_PCM_TRIGGER_RESUME:
        case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
                if (saif->state == MXS_SAIF_STATE_RUNNING)
                        return 0;

                dev_dbg(cpu_dai->dev, "start\n");

                ret = clk_enable(master_saif->clk);
                if (ret) {
                        dev_err(saif->dev, "Failed to enable master clock\n");
                        return ret;
                }

                /*
                 * If the saif's master is not itself, we also need to enable
                 * itself clk for its internal basic logic to work.
                 */
                if (saif != master_saif) {
                        ret = clk_enable(saif->clk);
                        if (ret) {
                                dev_err(saif->dev, "Failed to enable master clock\n");
                                clk_disable(master_saif->clk);
                                return ret;
                        }

                        __raw_writel(BM_SAIF_CTRL_RUN,
                                saif->base + SAIF_CTRL + MXS_SET_ADDR);
                }

                if (!master_saif->mclk_in_use)
                        __raw_writel(BM_SAIF_CTRL_RUN,
                                master_saif->base + SAIF_CTRL + MXS_SET_ADDR);

                if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
                        /*
                         * write data to saif data register to trigger
                         * the transfer.
                         * For 24-bit format the 32-bit FIFO register stores
                         * only one channel, so we need to write twice.
                         * This is also safe for the other non 24-bit formats.
                         */
                        __raw_writel(0, saif->base + SAIF_DATA);
                        __raw_writel(0, saif->base + SAIF_DATA);
                } else {
                        /*
                         * read data from saif data register to trigger
                         * the receive.
                         * For 24-bit format the 32-bit FIFO register stores
                         * only one channel, so we need to read twice.
                         * This is also safe for the other non 24-bit formats.
                         */
                        __raw_readl(saif->base + SAIF_DATA);
                        __raw_readl(saif->base + SAIF_DATA);
                }

                master_saif->ongoing = 1;
                saif->state = MXS_SAIF_STATE_RUNNING;

                dev_dbg(saif->dev, "CTRL 0x%x STAT 0x%x\n",
                        __raw_readl(saif->base + SAIF_CTRL),
                        __raw_readl(saif->base + SAIF_STAT));

                dev_dbg(master_saif->dev, "CTRL 0x%x STAT 0x%x\n",
                        __raw_readl(master_saif->base + SAIF_CTRL),
                        __raw_readl(master_saif->base + SAIF_STAT));
                break;
        case SNDRV_PCM_TRIGGER_SUSPEND:
        case SNDRV_PCM_TRIGGER_STOP:
        case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
                if (saif->state == MXS_SAIF_STATE_STOPPED)
                        return 0;

                dev_dbg(cpu_dai->dev, "stop\n");

                /* wait a while for the current sample to complete */
                delay = USEC_PER_SEC / master_saif->cur_rate;

                if (!master_saif->mclk_in_use) {
                        __raw_writel(BM_SAIF_CTRL_RUN,
                                master_saif->base + SAIF_CTRL + MXS_CLR_ADDR);
                        udelay(delay);
                }
                clk_disable(master_saif->clk);

                if (saif != master_saif) {
                        __raw_writel(BM_SAIF_CTRL_RUN,
                                saif->base + SAIF_CTRL + MXS_CLR_ADDR);
                        udelay(delay);
                        clk_disable(saif->clk);
                }

                master_saif->ongoing = 0;
                saif->state = MXS_SAIF_STATE_STOPPED;

                break;
        default:
                return -EINVAL;
        }

        return 0;
}

#define MXS_SAIF_RATES          SNDRV_PCM_RATE_8000_192000
#define MXS_SAIF_FORMATS \
        (SNDRV_PCM_FMTBIT_S16_LE | SNDRV_PCM_FMTBIT_S20_3LE | \
        SNDRV_PCM_FMTBIT_S24_LE)

static const struct snd_soc_dai_ops mxs_saif_dai_ops = {
        .startup = mxs_saif_startup,
        .shutdown = mxs_saif_shutdown,
        .trigger = mxs_saif_trigger,
        .prepare = mxs_saif_prepare,
        .hw_params = mxs_saif_hw_params,
        .set_sysclk = mxs_saif_set_dai_sysclk,
        .set_fmt = mxs_saif_set_dai_fmt,
};

static struct snd_soc_dai_driver mxs_saif_dai = {
        .name = "mxs-saif",
        .playback = {
                .channels_min = 2,
                .channels_max = 2,
                .rates = MXS_SAIF_RATES,
                .formats = MXS_SAIF_FORMATS,
        },
        .capture = {
                .channels_min = 2,
                .channels_max = 2,
                .rates = MXS_SAIF_RATES,
                .formats = MXS_SAIF_FORMATS,
        },
        .ops = &mxs_saif_dai_ops,
};

static const struct snd_soc_component_driver mxs_saif_component = {
        .name                   = "mxs-saif",
        .legacy_dai_naming      = 1,
};

static irqreturn_t mxs_saif_irq(int irq, void *dev_id)
{
        struct mxs_saif *saif = dev_id;
        unsigned int stat;

        stat = __raw_readl(saif->base + SAIF_STAT);
        if (!(stat & (BM_SAIF_STAT_FIFO_UNDERFLOW_IRQ |
                        BM_SAIF_STAT_FIFO_OVERFLOW_IRQ)))
                return IRQ_NONE;

        if (stat & BM_SAIF_STAT_FIFO_UNDERFLOW_IRQ) {
                dev_dbg(saif->dev, "underrun!!! %d\n", ++saif->fifo_underrun);
                __raw_writel(BM_SAIF_STAT_FIFO_UNDERFLOW_IRQ,
                                saif->base + SAIF_STAT + MXS_CLR_ADDR);
        }

        if (stat & BM_SAIF_STAT_FIFO_OVERFLOW_IRQ) {
                dev_dbg(saif->dev, "overrun!!! %d\n", ++saif->fifo_overrun);
                __raw_writel(BM_SAIF_STAT_FIFO_OVERFLOW_IRQ,
                                saif->base + SAIF_STAT + MXS_CLR_ADDR);
        }

        dev_dbg(saif->dev, "SAIF_CTRL %x SAIF_STAT %x\n",
               __raw_readl(saif->base + SAIF_CTRL),
               __raw_readl(saif->base + SAIF_STAT));

        return IRQ_HANDLED;
}

static int mxs_saif_mclk_init(struct platform_device *pdev)
{
        struct mxs_saif *saif = platform_get_drvdata(pdev);
        struct device_node *np = pdev->dev.of_node;
        struct clk *clk;
        int ret;

        clk = clk_register_divider(&pdev->dev, "mxs_saif_mclk",
                                   __clk_get_name(saif->clk), 0,
                                   saif->base + SAIF_CTRL,
                                   BP_SAIF_CTRL_BITCLK_MULT_RATE, 3,
                                   0, NULL);
        if (IS_ERR(clk)) {
                ret = PTR_ERR(clk);
                if (ret == -EEXIST)
                        return 0;
                dev_err(&pdev->dev, "failed to register mclk: %d\n", ret);
                return PTR_ERR(clk);
        }

        ret = of_clk_add_provider(np, of_clk_src_simple_get, clk);
        if (ret)
                return ret;

        return 0;
}

static int mxs_saif_probe(struct platform_device *pdev)
{
        struct device_node *np = pdev->dev.of_node;
        struct mxs_saif *saif;
        int irq, ret;
        struct device_node *master;

        saif = devm_kzalloc(&pdev->dev, sizeof(*saif), GFP_KERNEL);
        if (!saif)
                return -ENOMEM;

        ret = of_alias_get_id(np, "saif");
        if (ret < 0)
                return ret;
        else
                saif->id = ret;

        if (saif->id >= ARRAY_SIZE(mxs_saif)) {
                dev_err(&pdev->dev, "get wrong saif id\n");
                return -EINVAL;
        }

        /*
         * If there is no "fsl,saif-master" phandle, it's a saif
         * master.  Otherwise, it's a slave and its phandle points
         * to the master.
         */
        master = of_parse_phandle(np, "fsl,saif-master", 0);
        if (!master) {
                saif->master_id = saif->id;
        } else {
                ret = of_alias_get_id(master, "saif");
                of_node_put(master);
                if (ret < 0)
                        return ret;
                else
                        saif->master_id = ret;

                if (saif->master_id >= ARRAY_SIZE(mxs_saif)) {
                        dev_err(&pdev->dev, "get wrong master id\n");
                        return -EINVAL;
                }
        }

        mxs_saif[saif->id] = saif;

        saif->clk = devm_clk_get(&pdev->dev, NULL);
        if (IS_ERR(saif->clk)) {
                ret = PTR_ERR(saif->clk);
                dev_err(&pdev->dev, "Cannot get the clock: %d\n",
                        ret);
                return ret;
        }

        saif->base = devm_platform_ioremap_resource(pdev, 0);
        if (IS_ERR(saif->base))
                return PTR_ERR(saif->base);

        irq = platform_get_irq(pdev, 0);
        if (irq < 0)
                return irq;

        saif->dev = &pdev->dev;
        ret = devm_request_irq(&pdev->dev, irq, mxs_saif_irq, 0,
                               dev_name(&pdev->dev), saif);
        if (ret) {
                dev_err(&pdev->dev, "failed to request irq\n");
                return ret;
        }

        platform_set_drvdata(pdev, saif);

        /* We only support saif0 being tx and clock master */
        if (saif->id == 0) {
                ret = mxs_saif_mclk_init(pdev);
                if (ret)
                        dev_warn(&pdev->dev, "failed to init clocks\n");
        }

        ret = devm_snd_soc_register_component(&pdev->dev, &mxs_saif_component,
                                              &mxs_saif_dai, 1);
        if (ret) {
                dev_err(&pdev->dev, "register DAI failed\n");
                return ret;
        }

        ret = mxs_pcm_platform_register(&pdev->dev);
        if (ret) {
                dev_err(&pdev->dev, "register PCM failed: %d\n", ret);
                return ret;
        }

        return 0;
}

static const struct of_device_id mxs_saif_dt_ids[] = {
        { .compatible = "fsl,imx28-saif", },
        { /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, mxs_saif_dt_ids);

static struct platform_driver mxs_saif_driver = {
        .probe = mxs_saif_probe,

        .driver = {
                .name = "mxs-saif",
                .of_match_table = mxs_saif_dt_ids,
        },
};

module_platform_driver(mxs_saif_driver);

MODULE_AUTHOR("Freescale Semiconductor, Inc.");
MODULE_DESCRIPTION("MXS ASoC SAIF driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:mxs-saif");