linux_kernel/sound/soc/fsl/fsl_sai.c

/*
 * Freescale ALSA SoC Digital Audio Interface (SAI) driver.
 *
 * Copyright 2012-2015 Freescale Semiconductor, Inc.
 *
 * 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.
 *
 */

#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/dmaengine.h>
#include <linux/module.h>
#include <linux/of_address.h>
#include <linux/regmap.h>
#include <linux/slab.h>
#include <sound/core.h>
#include <sound/dmaengine_pcm.h>
#include <sound/pcm_params.h>

#include "fsl_sai.h"
#include "imx-pcm.h"

#define FSL_SAI_FLAGS (FSL_SAI_CSR_SEIE |\
		       FSL_SAI_CSR_FEIE)

static u32 fsl_sai_rates[] = {
	8000, 11025, 12000, 16000, 22050,
	24000, 32000, 44100, 48000, 64000,
	88200, 96000, 176400, 192000
};

static struct snd_pcm_hw_constraint_list fsl_sai_rate_constraints = {
	.count = ARRAY_SIZE(fsl_sai_rates),
	.list = fsl_sai_rates,
};

static irqreturn_t fsl_sai_isr(int irq, void *devid)
{
	struct fsl_sai *sai = (struct fsl_sai *)devid;
	struct device *dev = &sai->pdev->dev;
	u32 flags, xcsr, mask;
	bool irq_none = true;

	/*
	 * Both IRQ status bits and IRQ mask bits are in the xCSR but
	 * different shifts. And we here create a mask only for those
	 * IRQs that we activated.
	 */
	mask = (FSL_SAI_FLAGS >> FSL_SAI_CSR_xIE_SHIFT) << FSL_SAI_CSR_xF_SHIFT;

	/* Tx IRQ */
	regmap_read(sai->regmap, FSL_SAI_TCSR, &xcsr);
	flags = xcsr & mask;

	if (flags)
		irq_none = false;
	else
		goto irq_rx;

	if (flags & FSL_SAI_CSR_WSF)
		dev_dbg(dev, "isr: Start of Tx word detected\n");

	if (flags & FSL_SAI_CSR_SEF)
		dev_warn(dev, "isr: Tx Frame sync error detected\n");

	if (flags & FSL_SAI_CSR_FEF) {
		dev_warn(dev, "isr: Transmit underrun detected\n");
		/* FIFO reset for safety */
		xcsr |= FSL_SAI_CSR_FR;
	}

	if (flags & FSL_SAI_CSR_FWF)
		dev_dbg(dev, "isr: Enabled transmit FIFO is empty\n");

	if (flags & FSL_SAI_CSR_FRF)
		dev_dbg(dev, "isr: Transmit FIFO watermark has been reached\n");

	flags &= FSL_SAI_CSR_xF_W_MASK;
	xcsr &= ~FSL_SAI_CSR_xF_MASK;

	if (flags)
		regmap_write(sai->regmap, FSL_SAI_TCSR, flags | xcsr);

irq_rx:
	/* Rx IRQ */
	regmap_read(sai->regmap, FSL_SAI_RCSR, &xcsr);
	flags = xcsr & mask;

	if (flags)
		irq_none = false;
	else
		goto out;

	if (flags & FSL_SAI_CSR_WSF)
		dev_dbg(dev, "isr: Start of Rx word detected\n");

	if (flags & FSL_SAI_CSR_SEF)
		dev_warn(dev, "isr: Rx Frame sync error detected\n");

	if (flags & FSL_SAI_CSR_FEF) {
		dev_warn(dev, "isr: Receive overflow detected\n");
		/* FIFO reset for safety */
		xcsr |= FSL_SAI_CSR_FR;
	}

	if (flags & FSL_SAI_CSR_FWF)
		dev_dbg(dev, "isr: Enabled receive FIFO is full\n");

	if (flags & FSL_SAI_CSR_FRF)
		dev_dbg(dev, "isr: Receive FIFO watermark has been reached\n");

	flags &= FSL_SAI_CSR_xF_W_MASK;
	xcsr &= ~FSL_SAI_CSR_xF_MASK;

	if (flags)
		regmap_write(sai->regmap, FSL_SAI_RCSR, flags | xcsr);

out:
	if (irq_none)
		return IRQ_NONE;
	else
		return IRQ_HANDLED;
}

static int fsl_sai_set_dai_sysclk_tr(struct snd_soc_dai *cpu_dai,
		int clk_id, unsigned int freq, int fsl_dir)
{
	struct fsl_sai *sai = snd_soc_dai_get_drvdata(cpu_dai);
	bool tx = fsl_dir == FSL_FMT_TRANSMITTER;
	u32 val_cr2 = 0;

	switch (clk_id) {
	case FSL_SAI_CLK_BUS:
		val_cr2 |= FSL_SAI_CR2_MSEL_BUS;
		break;
	case FSL_SAI_CLK_MAST1:
		val_cr2 |= FSL_SAI_CR2_MSEL_MCLK1;
		break;
	case FSL_SAI_CLK_MAST2:
		val_cr2 |= FSL_SAI_CR2_MSEL_MCLK2;
		break;
	case FSL_SAI_CLK_MAST3:
		val_cr2 |= FSL_SAI_CR2_MSEL_MCLK3;
		break;
	default:
		return -EINVAL;
	}

	regmap_update_bits(sai->regmap, FSL_SAI_xCR2(tx),
			   FSL_SAI_CR2_MSEL_MASK, val_cr2);

	return 0;
}

static int fsl_sai_set_dai_sysclk(struct snd_soc_dai *cpu_dai,
		int clk_id, unsigned int freq, int dir)
{
	int ret;

	if (dir == SND_SOC_CLOCK_IN)
		return 0;

	ret = fsl_sai_set_dai_sysclk_tr(cpu_dai, clk_id, freq,
					FSL_FMT_TRANSMITTER);
	if (ret) {
		dev_err(cpu_dai->dev, "Cannot set tx sysclk: %d\n", ret);
		return ret;
	}

	ret = fsl_sai_set_dai_sysclk_tr(cpu_dai, clk_id, freq,
					FSL_FMT_RECEIVER);
	if (ret)
		dev_err(cpu_dai->dev, "Cannot set rx sysclk: %d\n", ret);

	return ret;
}

static int fsl_sai_set_dai_fmt_tr(struct snd_soc_dai *cpu_dai,
				unsigned int fmt, int fsl_dir)
{
	struct fsl_sai *sai = snd_soc_dai_get_drvdata(cpu_dai);
	bool tx = fsl_dir == FSL_FMT_TRANSMITTER;
	u32 val_cr2 = 0, val_cr4 = 0;

	if (!sai->is_lsb_first)
		val_cr4 |= FSL_SAI_CR4_MF;

	/* DAI mode */
	switch (fmt & SND_SOC_DAIFMT_FORMAT_MASK) {
	case SND_SOC_DAIFMT_I2S:
		/*
		 * Frame low, 1clk before data, one word length for frame sync,
		 * frame sync starts one serial clock cycle earlier,
		 * that is, together with the last bit of the previous
		 * data word.
		 */
		val_cr2 |= FSL_SAI_CR2_BCP;
		val_cr4 |= FSL_SAI_CR4_FSE | FSL_SAI_CR4_FSP;
		break;
	case SND_SOC_DAIFMT_LEFT_J:
		/*
		 * Frame high, one word length for frame sync,
		 * frame sync asserts with the first bit of the frame.
		 */
		val_cr2 |= FSL_SAI_CR2_BCP;
		break;
	case SND_SOC_DAIFMT_DSP_A:
		/*
		 * Frame high, 1clk before data, one bit for frame sync,
		 * frame sync starts one serial clock cycle earlier,
		 * that is, together with the last bit of the previous
		 * data word.
		 */
		val_cr2 |= FSL_SAI_CR2_BCP;
		val_cr4 |= FSL_SAI_CR4_FSE;
		sai->is_dsp_mode = true;
		break;
	case SND_SOC_DAIFMT_DSP_B:
		/*
		 * Frame high, one bit for frame sync,
		 * frame sync asserts with the first bit of the frame.
		 */
		val_cr2 |= FSL_SAI_CR2_BCP;
		sai->is_dsp_mode = true;
		break;
	case SND_SOC_DAIFMT_RIGHT_J:
		/* To be done */
	default:
		return -EINVAL;
	}

	/* DAI clock inversion */
	switch (fmt & SND_SOC_DAIFMT_INV_MASK) {
	case SND_SOC_DAIFMT_IB_IF:
		/* Invert both clocks */
		val_cr2 ^= FSL_SAI_CR2_BCP;
		val_cr4 ^= FSL_SAI_CR4_FSP;
		break;
	case SND_SOC_DAIFMT_IB_NF:
		/* Invert bit clock */
		val_cr2 ^= FSL_SAI_CR2_BCP;
		break;
	case SND_SOC_DAIFMT_NB_IF:
		/* Invert frame clock */
		val_cr4 ^= FSL_SAI_CR4_FSP;
		break;
	case SND_SOC_DAIFMT_NB_NF:
		/* Nothing to do for both normal cases */
		break;
	default:
		return -EINVAL;
	}

	/* DAI clock master masks */
	switch (fmt & SND_SOC_DAIFMT_MASTER_MASK) {
	case SND_SOC_DAIFMT_CBS_CFS:
		val_cr2 |= FSL_SAI_CR2_BCD_MSTR;
		val_cr4 |= FSL_SAI_CR4_FSD_MSTR;
		break;
	case SND_SOC_DAIFMT_CBM_CFM:
		sai->is_slave_mode = true;
		break;
	case SND_SOC_DAIFMT_CBS_CFM:
		val_cr2 |= FSL_SAI_CR2_BCD_MSTR;
		break;
	case SND_SOC_DAIFMT_CBM_CFS:
		val_cr4 |= FSL_SAI_CR4_FSD_MSTR;
		sai->is_slave_mode = true;
		break;
	default:
		return -EINVAL;
	}

	regmap_update_bits(sai->regmap, FSL_SAI_xCR2(tx),
			   FSL_SAI_CR2_BCP | FSL_SAI_CR2_BCD_MSTR, val_cr2);
	regmap_update_bits(sai->regmap, FSL_SAI_xCR4(tx),
			   FSL_SAI_CR4_MF | FSL_SAI_CR4_FSE |
			   FSL_SAI_CR4_FSP | FSL_SAI_CR4_FSD_MSTR, val_cr4);

	return 0;
}

static int fsl_sai_set_dai_fmt(struct snd_soc_dai *cpu_dai, unsigned int fmt)
{
	int ret;

	ret = fsl_sai_set_dai_fmt_tr(cpu_dai, fmt, FSL_FMT_TRANSMITTER);
	if (ret) {
		dev_err(cpu_dai->dev, "Cannot set tx format: %d\n", ret);
		return ret;
	}

	ret = fsl_sai_set_dai_fmt_tr(cpu_dai, fmt, FSL_FMT_RECEIVER);
	if (ret)
		dev_err(cpu_dai->dev, "Cannot set rx format: %d\n", ret);

	return ret;
}

static int fsl_sai_set_bclk(struct snd_soc_dai *dai, bool tx, u32 freq)
{
	struct fsl_sai *sai = snd_soc_dai_get_drvdata(dai);
	unsigned long clk_rate;
	u32 savediv = 0, ratio, savesub = freq;
	u32 id;
	int ret = 0;

	/* Don't apply to slave mode */
	if (sai->is_slave_mode)
		return 0;

	for (id = 0; id < FSL_SAI_MCLK_MAX; id++) {
		clk_rate = clk_get_rate(sai->mclk_clk[id]);
		if (!clk_rate)
			continue;

		ratio = clk_rate / freq;

		ret = clk_rate - ratio * freq;

		/*
		 * Drop the source that can not be
		 * divided into the required rate.
		 */
		if (ret != 0 && clk_rate / ret < 1000)
			continue;

		dev_dbg(dai->dev,
			"ratio %d for freq %dHz based on clock %ldHz\n",
			ratio, freq, clk_rate);

		if (ratio % 2 == 0 && ratio >= 2 && ratio <= 512)
			ratio /= 2;
		else
			continue;

		if (ret < savesub) {
			savediv = ratio;
			sai->mclk_id[tx] = id;
			savesub = ret;
		}

		if (ret == 0)
			break;
	}

	if (savediv == 0) {
		dev_err(dai->dev, "failed to derive required %cx rate: %d\n",
				tx ? 'T' : 'R', freq);
		return -EINVAL;
	}

	if ((tx && sai->synchronous[TX]) || (!tx && !sai->synchronous[RX])) {
		regmap_update_bits(sai->regmap, FSL_SAI_RCR2,
				   FSL_SAI_CR2_MSEL_MASK,
				   FSL_SAI_CR2_MSEL(sai->mclk_id[tx]));
		regmap_update_bits(sai->regmap, FSL_SAI_RCR2,
				   FSL_SAI_CR2_DIV_MASK, savediv - 1);
	} else {
		regmap_update_bits(sai->regmap, FSL_SAI_TCR2,
				   FSL_SAI_CR2_MSEL_MASK,
				   FSL_SAI_CR2_MSEL(sai->mclk_id[tx]));
		regmap_update_bits(sai->regmap, FSL_SAI_TCR2,
				   FSL_SAI_CR2_DIV_MASK, savediv - 1);
	}

	dev_dbg(dai->dev, "best fit: clock id=%d, div=%d, deviation =%d\n",
			sai->mclk_id[tx], savediv, savesub);

	return 0;
}

static int fsl_sai_hw_params(struct snd_pcm_substream *substream,
		struct snd_pcm_hw_params *params,
		struct snd_soc_dai *cpu_dai)
{
	struct fsl_sai *sai = snd_soc_dai_get_drvdata(cpu_dai);
	bool tx = substream->stream == SNDRV_PCM_STREAM_PLAYBACK;
	unsigned int channels = params_channels(params);
	u32 word_width = snd_pcm_format_width(params_format(params));
	u32 val_cr4 = 0, val_cr5 = 0;
	int ret;

	if (!sai->is_slave_mode) {
		ret = fsl_sai_set_bclk(cpu_dai, tx,
			2 * word_width * params_rate(params));
		if (ret)
			return ret;

		/* Do not enable the clock if it is already enabled */
		if (!(sai->mclk_streams & BIT(substream->stream))) {
			ret = clk_prepare_enable(sai->mclk_clk[sai->mclk_id[tx]]);
			if (ret)
				return ret;

			sai->mclk_streams |= BIT(substream->stream);
		}

	}

	if (!sai->is_dsp_mode)
		val_cr4 |= FSL_SAI_CR4_SYWD(word_width);

	val_cr5 |= FSL_SAI_CR5_WNW(word_width);
	val_cr5 |= FSL_SAI_CR5_W0W(word_width);

	if (sai->is_lsb_first)
		val_cr5 |= FSL_SAI_CR5_FBT(0);
	else
		val_cr5 |= FSL_SAI_CR5_FBT(word_width - 1);

	val_cr4 |= FSL_SAI_CR4_FRSZ(channels);

	regmap_update_bits(sai->regmap, FSL_SAI_xCR4(tx),
			   FSL_SAI_CR4_SYWD_MASK | FSL_SAI_CR4_FRSZ_MASK,
			   val_cr4);
	regmap_update_bits(sai->regmap, FSL_SAI_xCR5(tx),
			   FSL_SAI_CR5_WNW_MASK | FSL_SAI_CR5_W0W_MASK |
			   FSL_SAI_CR5_FBT_MASK, val_cr5);
	regmap_write(sai->regmap, FSL_SAI_xMR(tx), ~0UL - ((1 << channels) - 1));

	return 0;
}

static int fsl_sai_hw_free(struct snd_pcm_substream *substream,
		struct snd_soc_dai *cpu_dai)
{
	struct fsl_sai *sai = snd_soc_dai_get_drvdata(cpu_dai);
	bool tx = substream->stream == SNDRV_PCM_STREAM_PLAYBACK;

	if (!sai->is_slave_mode &&
			sai->mclk_streams & BIT(substream->stream)) {
		clk_disable_unprepare(sai->mclk_clk[sai->mclk_id[tx]]);
		sai->mclk_streams &= ~BIT(substream->stream);
	}

	return 0;
}


static int fsl_sai_trigger(struct snd_pcm_substream *substream, int cmd,
		struct snd_soc_dai *cpu_dai)
{
	struct fsl_sai *sai = snd_soc_dai_get_drvdata(cpu_dai);
	bool tx = substream->stream == SNDRV_PCM_STREAM_PLAYBACK;
	u32 xcsr, count = 100;

	/*
	 * Asynchronous mode: Clear SYNC for both Tx and Rx.
	 * Rx sync with Tx clocks: Clear SYNC for Tx, set it for Rx.
	 * Tx sync with Rx clocks: Clear SYNC for Rx, set it for Tx.
	 */
	regmap_update_bits(sai->regmap, FSL_SAI_TCR2, FSL_SAI_CR2_SYNC, 0);
	regmap_update_bits(sai->regmap, FSL_SAI_RCR2, FSL_SAI_CR2_SYNC,
			   sai->synchronous[RX] ? FSL_SAI_CR2_SYNC : 0);

	/*
	 * It is recommended that the transmitter is the last enabled
	 * and the first disabled.
	 */
	switch (cmd) {
	case SNDRV_PCM_TRIGGER_START:
	case SNDRV_PCM_TRIGGER_RESUME:
	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
		regmap_update_bits(sai->regmap, FSL_SAI_xCSR(tx),
				   FSL_SAI_CSR_FRDE, FSL_SAI_CSR_FRDE);

		regmap_update_bits(sai->regmap, FSL_SAI_RCSR,
				   FSL_SAI_CSR_TERE, FSL_SAI_CSR_TERE);
		regmap_update_bits(sai->regmap, FSL_SAI_TCSR,
				   FSL_SAI_CSR_TERE, FSL_SAI_CSR_TERE);

		regmap_update_bits(sai->regmap, FSL_SAI_xCSR(tx),
				   FSL_SAI_CSR_xIE_MASK, FSL_SAI_FLAGS);
		break;
	case SNDRV_PCM_TRIGGER_STOP:
	case SNDRV_PCM_TRIGGER_SUSPEND:
	case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
		regmap_update_bits(sai->regmap, FSL_SAI_xCSR(tx),
				   FSL_SAI_CSR_FRDE, 0);
		regmap_update_bits(sai->regmap, FSL_SAI_xCSR(tx),
				   FSL_SAI_CSR_xIE_MASK, 0);

		/* Check if the opposite FRDE is also disabled */
		regmap_read(sai->regmap, FSL_SAI_xCSR(!tx), &xcsr);
		if (!(xcsr & FSL_SAI_CSR_FRDE)) {
			/* Disable both directions and reset their FIFOs */
			regmap_update_bits(sai->regmap, FSL_SAI_TCSR,
					   FSL_SAI_CSR_TERE, 0);
			regmap_update_bits(sai->regmap, FSL_SAI_RCSR,
					   FSL_SAI_CSR_TERE, 0);

			/* TERE will remain set till the end of current frame */
			do {
				udelay(10);
				regmap_read(sai->regmap, FSL_SAI_xCSR(tx), &xcsr);
			} while (--count && xcsr & FSL_SAI_CSR_TERE);

			regmap_update_bits(sai->regmap, FSL_SAI_TCSR,
					   FSL_SAI_CSR_FR, FSL_SAI_CSR_FR);
			regmap_update_bits(sai->regmap, FSL_SAI_RCSR,
					   FSL_SAI_CSR_FR, FSL_SAI_CSR_FR);
		}
		break;
	default:
		return -EINVAL;
	}

	return 0;
}

static int fsl_sai_startup(struct snd_pcm_substream *substream,
		struct snd_soc_dai *cpu_dai)
{
	struct fsl_sai *sai = snd_soc_dai_get_drvdata(cpu_dai);
	bool tx = substream->stream == SNDRV_PCM_STREAM_PLAYBACK;
	struct device *dev = &sai->pdev->dev;
	int ret;

	ret = clk_prepare_enable(sai->bus_clk);
	if (ret) {
		dev_err(dev, "failed to enable bus clock: %d\n", ret);
		return ret;
	}

	regmap_update_bits(sai->regmap, FSL_SAI_xCR3(tx), FSL_SAI_CR3_TRCE,
			   FSL_SAI_CR3_TRCE);

	ret = snd_pcm_hw_constraint_list(substream->runtime, 0,
			SNDRV_PCM_HW_PARAM_RATE, &fsl_sai_rate_constraints);

	return ret;
}

static void fsl_sai_shutdown(struct snd_pcm_substream *substream,
		struct snd_soc_dai *cpu_dai)
{
	struct fsl_sai *sai = snd_soc_dai_get_drvdata(cpu_dai);
	bool tx = substream->stream == SNDRV_PCM_STREAM_PLAYBACK;

	regmap_update_bits(sai->regmap, FSL_SAI_xCR3(tx), FSL_SAI_CR3_TRCE, 0);

	clk_disable_unprepare(sai->bus_clk);
}

static const struct snd_soc_dai_ops fsl_sai_pcm_dai_ops = {
	.set_sysclk	= fsl_sai_set_dai_sysclk,
	.set_fmt	= fsl_sai_set_dai_fmt,
	.hw_params	= fsl_sai_hw_params,
	.hw_free	= fsl_sai_hw_free,
	.trigger	= fsl_sai_trigger,
	.startup	= fsl_sai_startup,
	.shutdown	= fsl_sai_shutdown,
};

static int fsl_sai_dai_probe(struct snd_soc_dai *cpu_dai)
{
	struct fsl_sai *sai = dev_get_drvdata(cpu_dai->dev);

	/* Software Reset for both Tx and Rx */
	regmap_write(sai->regmap, FSL_SAI_TCSR, FSL_SAI_CSR_SR);
	regmap_write(sai->regmap, FSL_SAI_RCSR, FSL_SAI_CSR_SR);
	/* Clear SR bit to finish the reset */
	regmap_write(sai->regmap, FSL_SAI_TCSR, 0);
	regmap_write(sai->regmap, FSL_SAI_RCSR, 0);

	regmap_update_bits(sai->regmap, FSL_SAI_TCR1, FSL_SAI_CR1_RFW_MASK,
			   FSL_SAI_MAXBURST_TX * 2);
	regmap_update_bits(sai->regmap, FSL_SAI_RCR1, FSL_SAI_CR1_RFW_MASK,
			   FSL_SAI_MAXBURST_RX - 1);

	snd_soc_dai_init_dma_data(cpu_dai, &sai->dma_params_tx,
				&sai->dma_params_rx);

	snd_soc_dai_set_drvdata(cpu_dai, sai);

	return 0;
}

static struct snd_soc_dai_driver fsl_sai_dai = {
	.probe = fsl_sai_dai_probe,
	.playback = {
		.stream_name = "CPU-Playback",
		.channels_min = 1,
		.channels_max = 2,
		.rate_min = 8000,
		.rate_max = 192000,
		.rates = SNDRV_PCM_RATE_KNOT,
		.formats = FSL_SAI_FORMATS,
	},
	.capture = {
		.stream_name = "CPU-Capture",
		.channels_min = 1,
		.channels_max = 2,
		.rate_min = 8000,
		.rate_max = 192000,
		.rates = SNDRV_PCM_RATE_KNOT,
		.formats = FSL_SAI_FORMATS,
	},
	.ops = &fsl_sai_pcm_dai_ops,
};

static const struct snd_soc_component_driver fsl_component = {
	.name           = "fsl-sai",
};

static bool fsl_sai_readable_reg(struct device *dev, unsigned int reg)
{
	switch (reg) {
	case FSL_SAI_TCSR:
	case FSL_SAI_TCR1:
	case FSL_SAI_TCR2:
	case FSL_SAI_TCR3:
	case FSL_SAI_TCR4:
	case FSL_SAI_TCR5:
	case FSL_SAI_TFR:
	case FSL_SAI_TMR:
	case FSL_SAI_RCSR:
	case FSL_SAI_RCR1:
	case FSL_SAI_RCR2:
	case FSL_SAI_RCR3:
	case FSL_SAI_RCR4:
	case FSL_SAI_RCR5:
	case FSL_SAI_RDR:
	case FSL_SAI_RFR:
	case FSL_SAI_RMR:
		return true;
	default:
		return false;
	}
}

static bool fsl_sai_volatile_reg(struct device *dev, unsigned int reg)
{
	switch (reg) {
	case FSL_SAI_TFR:
	case FSL_SAI_RFR:
	case FSL_SAI_TDR:
	case FSL_SAI_RDR:
		return true;
	default:
		return false;
	}

}

static bool fsl_sai_writeable_reg(struct device *dev, unsigned int reg)
{
	switch (reg) {
	case FSL_SAI_TCSR:
	case FSL_SAI_TCR1:
	case FSL_SAI_TCR2:
	case FSL_SAI_TCR3:
	case FSL_SAI_TCR4:
	case FSL_SAI_TCR5:
	case FSL_SAI_TDR:
	case FSL_SAI_TMR:
	case FSL_SAI_RCSR:
	case FSL_SAI_RCR1:
	case FSL_SAI_RCR2:
	case FSL_SAI_RCR3:
	case FSL_SAI_RCR4:
	case FSL_SAI_RCR5:
	case FSL_SAI_RMR:
		return true;
	default:
		return false;
	}
}

static const struct regmap_config fsl_sai_regmap_config = {
	.reg_bits = 32,
	.reg_stride = 4,
	.val_bits = 32,

	.max_register = FSL_SAI_RMR,
	.readable_reg = fsl_sai_readable_reg,
	.volatile_reg = fsl_sai_volatile_reg,
	.writeable_reg = fsl_sai_writeable_reg,
};

static int fsl_sai_probe(struct platform_device *pdev)
{
	struct device_node *np = pdev->dev.of_node;
	struct fsl_sai *sai;
	struct resource *res;
	void __iomem *base;
	char tmp[8];
	int irq, ret, i;

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

	sai->pdev = pdev;

	if (of_device_is_compatible(pdev->dev.of_node, "fsl,imx6sx-sai"))
		sai->sai_on_imx = true;

	sai->is_lsb_first = of_property_read_bool(np, "lsb-first");

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	base = devm_ioremap_resource(&pdev->dev, res);
	if (IS_ERR(base))
		return PTR_ERR(base);

	sai->regmap = devm_regmap_init_mmio_clk(&pdev->dev,
			"bus", base, &fsl_sai_regmap_config);

	/* Compatible with old DTB cases */
	if (IS_ERR(sai->regmap))
		sai->regmap = devm_regmap_init_mmio_clk(&pdev->dev,
				"sai", base, &fsl_sai_regmap_config);
	if (IS_ERR(sai->regmap)) {
		dev_err(&pdev->dev, "regmap init failed\n");
		return PTR_ERR(sai->regmap);
	}

	/* No error out for old DTB cases but only mark the clock NULL */
	sai->bus_clk = devm_clk_get(&pdev->dev, "bus");
	if (IS_ERR(sai->bus_clk)) {
		dev_err(&pdev->dev, "failed to get bus clock: %ld\n",
				PTR_ERR(sai->bus_clk));
		sai->bus_clk = NULL;
	}

	sai->mclk_clk[0] = sai->bus_clk;
	for (i = 1; i < FSL_SAI_MCLK_MAX; i++) {
		sprintf(tmp, "mclk%d", i);
		sai->mclk_clk[i] = devm_clk_get(&pdev->dev, tmp);
		if (IS_ERR(sai->mclk_clk[i])) {
			dev_err(&pdev->dev, "failed to get mclk%d clock: %ld\n",
					i + 1, PTR_ERR(sai->mclk_clk[i]));
			sai->mclk_clk[i] = NULL;
		}
	}

	irq = platform_get_irq(pdev, 0);
	if (irq < 0) {
		dev_err(&pdev->dev, "no irq for node %s\n", pdev->name);
		return irq;
	}

	ret = devm_request_irq(&pdev->dev, irq, fsl_sai_isr, 0, np->name, sai);
	if (ret) {
		dev_err(&pdev->dev, "failed to claim irq %u\n", irq);
		return ret;
	}

	/* Sync Tx with Rx as default by following old DT binding */
	sai->synchronous[RX] = true;
	sai->synchronous[TX] = false;
	fsl_sai_dai.symmetric_rates = 1;
	fsl_sai_dai.symmetric_channels = 1;
	fsl_sai_dai.symmetric_samplebits = 1;

	if (of_find_property(np, "fsl,sai-synchronous-rx", NULL) &&
	    of_find_property(np, "fsl,sai-asynchronous", NULL)) {
		/* error out if both synchronous and asynchronous are present */
		dev_err(&pdev->dev, "invalid binding for synchronous mode\n");
		return -EINVAL;
	}

	if (of_find_property(np, "fsl,sai-synchronous-rx", NULL)) {
		/* Sync Rx with Tx */
		sai->synchronous[RX] = false;
		sai->synchronous[TX] = true;
	} else if (of_find_property(np, "fsl,sai-asynchronous", NULL)) {
		/* Discard all settings for asynchronous mode */
		sai->synchronous[RX] = false;
		sai->synchronous[TX] = false;
		fsl_sai_dai.symmetric_rates = 0;
		fsl_sai_dai.symmetric_channels = 0;
		fsl_sai_dai.symmetric_samplebits = 0;
	}

	sai->dma_params_rx.addr = res->start + FSL_SAI_RDR;
	sai->dma_params_tx.addr = res->start + FSL_SAI_TDR;
	sai->dma_params_rx.maxburst = FSL_SAI_MAXBURST_RX;
	sai->dma_params_tx.maxburst = FSL_SAI_MAXBURST_TX;

	platform_set_drvdata(pdev, sai);

	ret = devm_snd_soc_register_component(&pdev->dev, &fsl_component,
			&fsl_sai_dai, 1);
	if (ret)
		return ret;

	if (sai->sai_on_imx)
		return imx_pcm_dma_init(pdev, IMX_SAI_DMABUF_SIZE);
	else
		return devm_snd_dmaengine_pcm_register(&pdev->dev, NULL, 0);
}

static const struct of_device_id fsl_sai_ids[] = {
	{ .compatible = "fsl,vf610-sai", },
	{ .compatible = "fsl,imx6sx-sai", },
	{ /* sentinel */ }
};

static struct platform_driver fsl_sai_driver = {
	.probe = fsl_sai_probe,
	.driver = {
		.name = "fsl-sai",
		.of_match_table = fsl_sai_ids,
	},
};
module_platform_driver(fsl_sai_driver);

MODULE_DESCRIPTION("Freescale Soc SAI Interface");
MODULE_AUTHOR("Xiubo Li, <Li.Xiubo@freescale.com>");
MODULE_ALIAS("platform:fsl-sai");
MODULE_LICENSE("GPL");