sound/soc/imx/imx-ssi.c

/*
 * imx-ssi.c  --  ALSA Soc Audio Layer
 *
 * Copyright 2009 Sascha Hauer <s.hauer@pengutronix.de>
 *
 * This code is based on code copyrighted by Freescale,
 * Liam Girdwood, Javier Martin and probably others.
 *
 *  This program is free software; you can redistribute  it and/or modify it
 *  under  the terms of  the GNU General  Public License as published by the
 *  Free Software Foundation;  either version 2 of the  License, or (at your
 *  option) any later version.
 *
 *
 * The i.MX SSI core has some nasty limitations in AC97 mode. While most
 * sane processor vendors have a FIFO per AC97 slot, the i.MX has only
 * one FIFO which combines all valid receive slots. We cannot even select
 * which slots we want to receive. The WM9712 with which this driver
 * was developped with always sends GPIO status data in slot 12 which
 * we receive in our (PCM-) data stream. The only chance we have is to
 * manually skip this data in the FIQ handler. With sampling rates different
 * from 48000Hz not every frame has valid receive data, so the ratio
 * between pcm data and GPIO status data changes. Our FIQ handler is not
 * able to handle this, hence this driver only works with 48000Hz sampling
 * rate.
 * Reading and writing AC97 registers is another challenge. The core
 * provides us status bits when the read register is updated with *another*
 * value. When we read the same register two times (and the register still
 * contains the same value) these status bits are not set. We work
 * around this by not polling these bits but only wait a fixed delay.
 * 
 */

#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/device.h>
#include <linux/dma-mapping.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/slab.h>

#include <sound/core.h>
#include <sound/initval.h>
#include <sound/pcm.h>
#include <sound/pcm_params.h>
#include <sound/soc.h>

#include <mach/ssi.h>
#include <mach/hardware.h>

#include "imx-ssi.h"

#define SSI_SACNT_DEFAULT (SSI_SACNT_AC97EN | SSI_SACNT_FV)

/*
 * SSI Network Mode or TDM slots configuration.
 * Should only be called when port is inactive (i.e. SSIEN = 0).
 */
static int imx_ssi_set_dai_tdm_slot(struct snd_soc_dai *cpu_dai,
	unsigned int tx_mask, unsigned int rx_mask, int slots, int slot_width)
{
	struct imx_ssi *ssi = snd_soc_dai_get_drvdata(cpu_dai);
	u32 sccr;

	sccr = readl(ssi->base + SSI_STCCR);
	sccr &= ~SSI_STCCR_DC_MASK;
	sccr |= SSI_STCCR_DC(slots - 1);
	writel(sccr, ssi->base + SSI_STCCR);

	sccr = readl(ssi->base + SSI_SRCCR);
	sccr &= ~SSI_STCCR_DC_MASK;
	sccr |= SSI_STCCR_DC(slots - 1);
	writel(sccr, ssi->base + SSI_SRCCR);

	writel(tx_mask, ssi->base + SSI_STMSK);
	writel(rx_mask, ssi->base + SSI_SRMSK);

	return 0;
}

/*
 * SSI DAI format configuration.
 * Should only be called when port is inactive (i.e. SSIEN = 0).
 */
static int imx_ssi_set_dai_fmt(struct snd_soc_dai *cpu_dai, unsigned int fmt)
{
	struct imx_ssi *ssi = snd_soc_dai_get_drvdata(cpu_dai);
	u32 strcr = 0, scr;

	scr = readl(ssi->base + SSI_SCR) & ~(SSI_SCR_SYN | SSI_SCR_NET);

	/* DAI mode */
	switch (fmt & SND_SOC_DAIFMT_FORMAT_MASK) {
	case SND_SOC_DAIFMT_I2S:
		/* data on rising edge of bclk, frame low 1clk before data */
		strcr |= SSI_STCR_TFSI | SSI_STCR_TEFS | SSI_STCR_TXBIT0;
		scr |= SSI_SCR_NET;
		if (ssi->flags & IMX_SSI_USE_I2S_SLAVE) {
			scr &= ~SSI_I2S_MODE_MASK;
			scr |= SSI_SCR_I2S_MODE_SLAVE;
		}
		break;
	case SND_SOC_DAIFMT_LEFT_J:
		/* data on rising edge of bclk, frame high with data */
		strcr |= SSI_STCR_TXBIT0;
		break;
	case SND_SOC_DAIFMT_DSP_B:
		/* data on rising edge of bclk, frame high with data */
		strcr |= SSI_STCR_TFSL;
		break;
	case SND_SOC_DAIFMT_DSP_A:
		/* data on rising edge of bclk, frame high 1clk before data */
		strcr |= SSI_STCR_TFSL | SSI_STCR_TEFS;
		break;
	}

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

	/* DAI clock master masks */
	switch (fmt & SND_SOC_DAIFMT_MASTER_MASK) {
	case SND_SOC_DAIFMT_CBM_CFM:
		break;
	default:
		/* Master mode not implemented, needs handling of clocks. */
		return -EINVAL;
	}

	strcr |= SSI_STCR_TFEN0;

	if (ssi->flags & IMX_SSI_NET)
		scr |= SSI_SCR_NET;
	if (ssi->flags & IMX_SSI_SYN)
		scr |= SSI_SCR_SYN;

	writel(strcr, ssi->base + SSI_STCR);
	writel(strcr, ssi->base + SSI_SRCR);
	writel(scr, ssi->base + SSI_SCR);

	return 0;
}

/*
 * SSI system clock configuration.
 * Should only be called when port is inactive (i.e. SSIEN = 0).
 */
static int imx_ssi_set_dai_sysclk(struct snd_soc_dai *cpu_dai,
				  int clk_id, unsigned int freq, int dir)
{
	struct imx_ssi *ssi = snd_soc_dai_get_drvdata(cpu_dai);
	u32 scr;

	scr = readl(ssi->base + SSI_SCR);

	switch (clk_id) {
	case IMX_SSP_SYS_CLK:
		if (dir == SND_SOC_CLOCK_OUT)
			scr |= SSI_SCR_SYS_CLK_EN;
		else
			scr &= ~SSI_SCR_SYS_CLK_EN;
		break;
	default:
		return -EINVAL;
	}

	writel(scr, ssi->base + SSI_SCR);

	return 0;
}

/*
 * SSI Clock dividers
 * Should only be called when port is inactive (i.e. SSIEN = 0).
 */
static int imx_ssi_set_dai_clkdiv(struct snd_soc_dai *cpu_dai,
				  int div_id, int div)
{
	struct imx_ssi *ssi = snd_soc_dai_get_drvdata(cpu_dai);
	u32 stccr, srccr;

	stccr = readl(ssi->base + SSI_STCCR);
	srccr = readl(ssi->base + SSI_SRCCR);

	switch (div_id) {
	case IMX_SSI_TX_DIV_2:
		stccr &= ~SSI_STCCR_DIV2;
		stccr |= div;
		break;
	case IMX_SSI_TX_DIV_PSR:
		stccr &= ~SSI_STCCR_PSR;
		stccr |= div;
		break;
	case IMX_SSI_TX_DIV_PM:
		stccr &= ~0xff;
		stccr |= SSI_STCCR_PM(div);
		break;
	case IMX_SSI_RX_DIV_2:
		stccr &= ~SSI_STCCR_DIV2;
		stccr |= div;
		break;
	case IMX_SSI_RX_DIV_PSR:
		stccr &= ~SSI_STCCR_PSR;
		stccr |= div;
		break;
	case IMX_SSI_RX_DIV_PM:
		stccr &= ~0xff;
		stccr |= SSI_STCCR_PM(div);
		break;
	default:
		return -EINVAL;
	}

	writel(stccr, ssi->base + SSI_STCCR);
	writel(srccr, ssi->base + SSI_SRCCR);

	return 0;
}

/*
 * Should only be called when port is inactive (i.e. SSIEN = 0),
 * although can be called multiple times by upper layers.
 */
static int imx_ssi_hw_params(struct snd_pcm_substream *substream,
			     struct snd_pcm_hw_params *params,
			     struct snd_soc_dai *cpu_dai)
{
	struct imx_ssi *ssi = snd_soc_dai_get_drvdata(cpu_dai);
	struct imx_pcm_dma_params *dma_data;
	u32 reg, sccr;

	/* Tx/Rx config */
	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
		reg = SSI_STCCR;
		dma_data = &ssi->dma_params_tx;
	} else {
		reg = SSI_SRCCR;
		dma_data = &ssi->dma_params_rx;
	}

	if (ssi->flags & IMX_SSI_SYN)
		reg = SSI_STCCR;

	snd_soc_dai_set_dma_data(cpu_dai, substream, dma_data);

	sccr = readl(ssi->base + reg) & ~SSI_STCCR_WL_MASK;

	/* DAI data (word) size */
	switch (params_format(params)) {
	case SNDRV_PCM_FORMAT_S16_LE:
		sccr |= SSI_SRCCR_WL(16);
		break;
	case SNDRV_PCM_FORMAT_S20_3LE:
		sccr |= SSI_SRCCR_WL(20);
		break;
	case SNDRV_PCM_FORMAT_S24_LE:
		sccr |= SSI_SRCCR_WL(24);
		break;
	}

	writel(sccr, ssi->base + reg);

	return 0;
}

static int imx_ssi_trigger(struct snd_pcm_substream *substream, int cmd,
		struct snd_soc_dai *dai)
{
	struct imx_ssi *ssi = snd_soc_dai_get_drvdata(dai);
	unsigned int sier_bits, sier;
	unsigned int scr;

	scr = readl(ssi->base + SSI_SCR);
	sier = readl(ssi->base + SSI_SIER);

	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
		if (ssi->flags & IMX_SSI_DMA)
			sier_bits = SSI_SIER_TDMAE;
		else
			sier_bits = SSI_SIER_TIE | SSI_SIER_TFE0_EN;
	} else {
		if (ssi->flags & IMX_SSI_DMA)
			sier_bits = SSI_SIER_RDMAE;
		else
			sier_bits = SSI_SIER_RIE | SSI_SIER_RFF0_EN;
	}

	switch (cmd) {
	case SNDRV_PCM_TRIGGER_START:
	case SNDRV_PCM_TRIGGER_RESUME:
	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
		if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
			scr |= SSI_SCR_TE;
		else
			scr |= SSI_SCR_RE;
		sier |= sier_bits;

		if (++ssi->enabled == 1)
			scr |= SSI_SCR_SSIEN;

		break;

	case SNDRV_PCM_TRIGGER_STOP:
	case SNDRV_PCM_TRIGGER_SUSPEND:
	case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
		if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
			scr &= ~SSI_SCR_TE;
		else
			scr &= ~SSI_SCR_RE;
		sier &= ~sier_bits;

		if (--ssi->enabled == 0)
			scr &= ~SSI_SCR_SSIEN;

		break;
	default:
		return -EINVAL;
	}

	if (!(ssi->flags & IMX_SSI_USE_AC97))
		/* rx/tx are always enabled to access ac97 registers */
		writel(scr, ssi->base + SSI_SCR);

	writel(sier, ssi->base + SSI_SIER);

	return 0;
}

static struct snd_soc_dai_ops imx_ssi_pcm_dai_ops = {
	.hw_params	= imx_ssi_hw_params,
	.set_fmt	= imx_ssi_set_dai_fmt,
	.set_clkdiv	= imx_ssi_set_dai_clkdiv,
	.set_sysclk	= imx_ssi_set_dai_sysclk,
	.set_tdm_slot	= imx_ssi_set_dai_tdm_slot,
	.trigger	= imx_ssi_trigger,
};

int snd_imx_pcm_mmap(struct snd_pcm_substream *substream,
		struct vm_area_struct *vma)
{
	struct snd_pcm_runtime *runtime = substream->runtime;
	int ret;

	ret = dma_mmap_coherent(NULL, vma, runtime->dma_area,
			runtime->dma_addr, runtime->dma_bytes);

	pr_debug("%s: ret: %d %p 0x%08x 0x%08x\n", __func__, ret,
			runtime->dma_area,
			runtime->dma_addr,
			runtime->dma_bytes);
	return ret;
}
EXPORT_SYMBOL_GPL(snd_imx_pcm_mmap);

static int imx_pcm_preallocate_dma_buffer(struct snd_pcm *pcm, int stream)
{
	struct snd_pcm_substream *substream = pcm->streams[stream].substream;
	struct snd_dma_buffer *buf = &substream->dma_buffer;
	size_t size = IMX_SSI_DMABUF_SIZE;

	buf->dev.type = SNDRV_DMA_TYPE_DEV;
	buf->dev.dev = pcm->card->dev;
	buf->private_data = NULL;
	buf->area = dma_alloc_writecombine(pcm->card->dev, size,
					   &buf->addr, GFP_KERNEL);
	if (!buf->area)
		return -ENOMEM;
	buf->bytes = size;

	return 0;
}

static u64 imx_pcm_dmamask = DMA_BIT_MASK(32);

int imx_pcm_new(struct snd_card *card, struct snd_soc_dai *dai,
	struct snd_pcm *pcm)
{

	int ret = 0;

	if (!card->dev->dma_mask)
		card->dev->dma_mask = &imx_pcm_dmamask;
	if (!card->dev->coherent_dma_mask)
		card->dev->coherent_dma_mask = DMA_BIT_MASK(32);
	if (dai->driver->playback.channels_min) {
		ret = imx_pcm_preallocate_dma_buffer(pcm,
			SNDRV_PCM_STREAM_PLAYBACK);
		if (ret)
			goto out;
	}

	if (dai->driver->capture.channels_min) {
		ret = imx_pcm_preallocate_dma_buffer(pcm,
			SNDRV_PCM_STREAM_CAPTURE);
		if (ret)
			goto out;
	}

out:
	return ret;
}
EXPORT_SYMBOL_GPL(imx_pcm_new);

void imx_pcm_free(struct snd_pcm *pcm)
{
	struct snd_pcm_substream *substream;
	struct snd_dma_buffer *buf;
	int stream;

	for (stream = 0; stream < 2; stream++) {
		substream = pcm->streams[stream].substream;
		if (!substream)
			continue;

		buf = &substream->dma_buffer;
		if (!buf->area)
			continue;

		dma_free_writecombine(pcm->card->dev, buf->bytes,
				      buf->area, buf->addr);
		buf->area = NULL;
	}
}
EXPORT_SYMBOL_GPL(imx_pcm_free);

static struct snd_soc_dai_driver imx_ssi_dai = {
	.playback = {
		.channels_min = 2,
		.channels_max = 2,
		.rates = SNDRV_PCM_RATE_8000_96000,
		.formats = SNDRV_PCM_FMTBIT_S16_LE,
	},
	.capture = {
		.channels_min = 2,
		.channels_max = 2,
		.rates = SNDRV_PCM_RATE_8000_96000,
		.formats = SNDRV_PCM_FMTBIT_S16_LE,
	},
	.ops = &imx_ssi_pcm_dai_ops,
};

static int imx_ssi_dai_probe(struct snd_soc_dai *dai)
{
	struct imx_ssi *ssi = dev_get_drvdata(dai->dev);
	uint32_t val;

	snd_soc_dai_set_drvdata(dai, ssi);

	val = SSI_SFCSR_TFWM0(ssi->dma_params_tx.burstsize) |
		SSI_SFCSR_RFWM0(ssi->dma_params_rx.burstsize);
	writel(val, ssi->base + SSI_SFCSR);

	return 0;
}

static struct snd_soc_dai_driver imx_ac97_dai = {
	.probe = imx_ssi_dai_probe,
	.ac97_control = 1,
	.playback = {
		.stream_name = "AC97 Playback",
		.channels_min = 2,
		.channels_max = 2,
		.rates = SNDRV_PCM_RATE_48000,
		.formats = SNDRV_PCM_FMTBIT_S16_LE,
	},
	.capture = {
		.stream_name = "AC97 Capture",
		.channels_min = 2,
		.channels_max = 2,
		.rates = SNDRV_PCM_RATE_48000,
		.formats = SNDRV_PCM_FMTBIT_S16_LE,
	},
	.ops = &imx_ssi_pcm_dai_ops,
};

static void setup_channel_to_ac97(struct imx_ssi *imx_ssi)
{
	void __iomem *base = imx_ssi->base;

	writel(0x0, base + SSI_SCR);
	writel(0x0, base + SSI_STCR);
	writel(0x0, base + SSI_SRCR);

	writel(SSI_SCR_SYN | SSI_SCR_NET, base + SSI_SCR);

	writel(SSI_SFCSR_RFWM0(8) |
		SSI_SFCSR_TFWM0(8) |
		SSI_SFCSR_RFWM1(8) |
		SSI_SFCSR_TFWM1(8), base + SSI_SFCSR);

	writel(SSI_STCCR_WL(16) | SSI_STCCR_DC(12), base + SSI_STCCR);
	writel(SSI_STCCR_WL(16) | SSI_STCCR_DC(12), base + SSI_SRCCR);

	writel(SSI_SCR_SYN | SSI_SCR_NET | SSI_SCR_SSIEN, base + SSI_SCR);
	writel(SSI_SOR_WAIT(3), base + SSI_SOR);

	writel(SSI_SCR_SYN | SSI_SCR_NET | SSI_SCR_SSIEN |
			SSI_SCR_TE | SSI_SCR_RE,
			base + SSI_SCR);

	writel(SSI_SACNT_DEFAULT, base + SSI_SACNT);
	writel(0xff, base + SSI_SACCDIS);
	writel(0x300, base + SSI_SACCEN);
}

static struct imx_ssi *ac97_ssi;

static void imx_ssi_ac97_write(struct snd_ac97 *ac97, unsigned short reg,
		unsigned short val)
{
	struct imx_ssi *imx_ssi = ac97_ssi;
	void __iomem *base = imx_ssi->base;
	unsigned int lreg;
	unsigned int lval;

	if (reg > 0x7f)
		return;

	pr_debug("%s: 0x%02x 0x%04x\n", __func__, reg, val);

	lreg = reg <<  12;
	writel(lreg, base + SSI_SACADD);

	lval = val << 4;
	writel(lval , base + SSI_SACDAT);

	writel(SSI_SACNT_DEFAULT | SSI_SACNT_WR, base + SSI_SACNT);
	udelay(100);
}

static unsigned short imx_ssi_ac97_read(struct snd_ac97 *ac97,
		unsigned short reg)
{
	struct imx_ssi *imx_ssi = ac97_ssi;
	void __iomem *base = imx_ssi->base;

	unsigned short val = -1;
	unsigned int lreg;

	lreg = (reg & 0x7f) <<  12 ;
	writel(lreg, base + SSI_SACADD);
	writel(SSI_SACNT_DEFAULT | SSI_SACNT_RD, base + SSI_SACNT);

	udelay(100);

	val = (readl(base + SSI_SACDAT) >> 4) & 0xffff;

	pr_debug("%s: 0x%02x 0x%04x\n", __func__, reg, val);

	return val;
}

static void imx_ssi_ac97_reset(struct snd_ac97 *ac97)
{
	struct imx_ssi *imx_ssi = ac97_ssi;

	if (imx_ssi->ac97_reset)
		imx_ssi->ac97_reset(ac97);
}

static void imx_ssi_ac97_warm_reset(struct snd_ac97 *ac97)
{
	struct imx_ssi *imx_ssi = ac97_ssi;

	if (imx_ssi->ac97_warm_reset)
		imx_ssi->ac97_warm_reset(ac97);
}

struct snd_ac97_bus_ops soc_ac97_ops = {
	.read		= imx_ssi_ac97_read,
	.write		= imx_ssi_ac97_write,
	.reset		= imx_ssi_ac97_reset,
	.warm_reset	= imx_ssi_ac97_warm_reset
};
EXPORT_SYMBOL_GPL(soc_ac97_ops);

static int imx_ssi_probe(struct platform_device *pdev)
{
	struct resource *res;
	struct imx_ssi *ssi;
	struct imx_ssi_platform_data *pdata = pdev->dev.platform_data;
	int ret = 0;
	struct snd_soc_dai_driver *dai;

	ssi = kzalloc(sizeof(*ssi), GFP_KERNEL);
	if (!ssi)
		return -ENOMEM;
	dev_set_drvdata(&pdev->dev, ssi);

	if (pdata) {
		ssi->ac97_reset = pdata->ac97_reset;
		ssi->ac97_warm_reset = pdata->ac97_warm_reset;
		ssi->flags = pdata->flags;
	}

	ssi->irq = platform_get_irq(pdev, 0);

	ssi->clk = clk_get(&pdev->dev, NULL);
	if (IS_ERR(ssi->clk)) {
		ret = PTR_ERR(ssi->clk);
		dev_err(&pdev->dev, "Cannot get the clock: %d\n",
			ret);
		goto failed_clk;
	}
	clk_enable(ssi->clk);

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	if (!res) {
		ret = -ENODEV;
		goto failed_get_resource;
	}

	if (!request_mem_region(res->start, resource_size(res), DRV_NAME)) {
		dev_err(&pdev->dev, "request_mem_region failed\n");
		ret = -EBUSY;
		goto failed_get_resource;
	}

	ssi->base = ioremap(res->start, resource_size(res));
	if (!ssi->base) {
		dev_err(&pdev->dev, "ioremap failed\n");
		ret = -ENODEV;
		goto failed_ioremap;
	}

	if (ssi->flags & IMX_SSI_USE_AC97) {
		if (ac97_ssi) {
			ret = -EBUSY;
			goto failed_ac97;
		}
		ac97_ssi = ssi;
		setup_channel_to_ac97(ssi);
		dai = &imx_ac97_dai;
	} else
		dai = &imx_ssi_dai;

	writel(0x0, ssi->base + SSI_SIER);

	ssi->dma_params_rx.dma_addr = res->start + SSI_SRX0;
	ssi->dma_params_tx.dma_addr = res->start + SSI_STX0;

	res = platform_get_resource_byname(pdev, IORESOURCE_DMA, "tx0");
	if (res)
		ssi->dma_params_tx.dma = res->start;

	res = platform_get_resource_byname(pdev, IORESOURCE_DMA, "rx0");
	if (res)
		ssi->dma_params_rx.dma = res->start;

	if ((cpu_is_mx27() || cpu_is_mx21()) &&
			!(ssi->flags & IMX_SSI_USE_AC97) &&
			(ssi->flags & IMX_SSI_DMA)) {
		ssi->flags |= IMX_SSI_DMA;
	}

	platform_set_drvdata(pdev, ssi);

	ret = snd_soc_register_dai(&pdev->dev, dai);
	if (ret) {
		dev_err(&pdev->dev, "register DAI failed\n");
		goto failed_register;
	}

	ssi->soc_platform_pdev = platform_device_alloc("imx-fiq-pcm-audio", pdev->id);
	if (!ssi->soc_platform_pdev)
		goto failed_pdev_alloc;
	platform_set_drvdata(ssi->soc_platform_pdev, ssi);
	ret = platform_device_add(ssi->soc_platform_pdev);
	if (ret) {
		dev_err(&pdev->dev, "failed to add platform device\n");
		goto failed_pdev_add;
	}

	return 0;

failed_pdev_add:
	platform_device_put(ssi->soc_platform_pdev);
failed_pdev_alloc:
	snd_soc_unregister_dai(&pdev->dev);
failed_register:
failed_ac97:
	iounmap(ssi->base);
failed_ioremap:
	release_mem_region(res->start, resource_size(res));
failed_get_resource:
	clk_disable(ssi->clk);
	clk_put(ssi->clk);
failed_clk:
	kfree(ssi);

	return ret;
}

static int __devexit imx_ssi_remove(struct platform_device *pdev)
{
	struct resource *res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	struct imx_ssi *ssi = platform_get_drvdata(pdev);

	platform_device_del(ssi->soc_platform_pdev);
	platform_device_put(ssi->soc_platform_pdev);

	snd_soc_unregister_dai(&pdev->dev);

	if (ssi->flags & IMX_SSI_USE_AC97)
		ac97_ssi = NULL;

	iounmap(ssi->base);
	release_mem_region(res->start, resource_size(res));
	clk_disable(ssi->clk);
	clk_put(ssi->clk);
	kfree(ssi);

	return 0;
}

static struct platform_driver imx_ssi_driver = {
	.probe = imx_ssi_probe,
	.remove = __devexit_p(imx_ssi_remove),

	.driver = {
		.name = "imx-ssi-dai",
		.owner = THIS_MODULE,
	},
};

static int __init imx_ssi_init(void)
{
	return platform_driver_register(&imx_ssi_driver);
}

static void __exit imx_ssi_exit(void)
{
	platform_driver_unregister(&imx_ssi_driver);
}

module_init(imx_ssi_init);
module_exit(imx_ssi_exit);

/* Module information */
MODULE_AUTHOR("Sascha Hauer, <s.hauer@pengutronix.de>");
MODULE_DESCRIPTION("i.MX I2S/ac97 SoC Interface");
MODULE_LICENSE("GPL");