sound/soc/starfive/jh7110_tdm.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0
 /*
  * jh7110_tdm.c -- StarFive JH7110 TDM driver
  *
  * Copyright (C) 2023 StarFive Technology Co., Ltd.
  *
  * Author: Walker Chen <walker.chen@starfivetech.com>
  */

 #include <linux/clk.h>
 #include <linux/device.h>
 #include <linux/dmaengine.h>
 #include <linux/module.h>
 #include <linux/of_irq.h>
 #include <linux/of_platform.h>
 #include <linux/pm_runtime.h>
 #include <linux/regmap.h>
 #include <linux/reset.h>
 #include <linux/types.h>
 #include <sound/dmaengine_pcm.h>
 #include <sound/initval.h>
 #include <sound/pcm.h>
 #include <sound/pcm_params.h>
 #include <sound/soc.h>
 #include <sound/soc-dai.h>

 #define TDM_PCMGBCR			0x00
 	#define PCMGBCR_ENABLE		BIT(0)
 	#define CLKPOL_BIT		5
 	#define ELM_BIT			3
 	#define SYNCM_BIT		2
 	#define MS_BIT			1
 #define TDM_PCMTXCR			0x04
 	#define PCMTXCR_TXEN		BIT(0)
 	#define IFL_BIT			11
 	#define WL_BIT			8
 	#define SSCALE_BIT		4
 	#define SL_BIT			2
 	#define LRJ_BIT			1
 #define TDM_PCMRXCR			0x08
 	#define PCMRXCR_RXEN		BIT(0)
 #define TDM_PCMDIV			0x0c

 #define JH7110_TDM_FIFO			0x170c0000
 #define JH7110_TDM_FIFO_DEPTH		32

 enum TDM_MASTER_SLAVE_MODE {
 	TDM_AS_MASTER = 0,
 	TDM_AS_SLAVE,
 };

 enum TDM_CLKPOL {
 	/* tx raising and rx falling */
 	TDM_TX_RASING_RX_FALLING = 0,
 	/* tx falling and rx raising */
 	TDM_TX_FALLING_RX_RASING,
 };

 enum TDM_ELM {
 	/* only work while SYNCM=0 */
 	TDM_ELM_LATE = 0,
 	TDM_ELM_EARLY,
 };

 enum TDM_SYNCM {
 	/* short frame sync */
 	TDM_SYNCM_SHORT = 0,
 	/* long frame sync */
 	TDM_SYNCM_LONG,
 };

 enum TDM_IFL {
 	/* FIFO to send or received : half-1/2, Quarter-1/4 */
 	TDM_FIFO_HALF = 0,
 	TDM_FIFO_QUARTER,
 };

 enum TDM_WL {
 	/* send or received word length */
 	TDM_8BIT_WORD_LEN = 0,
 	TDM_16BIT_WORD_LEN,
 	TDM_20BIT_WORD_LEN,
 	TDM_24BIT_WORD_LEN,
 	TDM_32BIT_WORD_LEN,
 };

 enum TDM_SL {
 	/* send or received slot length */
 	TDM_8BIT_SLOT_LEN = 0,
 	TDM_16BIT_SLOT_LEN,
 	TDM_32BIT_SLOT_LEN,
 };

 enum TDM_LRJ {
 	/* left-justify or right-justify */
 	TDM_RIGHT_JUSTIFY = 0,
 	TDM_LEFT_JUSTIFT,
 };

 struct tdm_chan_cfg {
 	enum TDM_IFL ifl;
 	enum TDM_WL  wl;
 	unsigned char sscale;
 	enum TDM_SL  sl;
 	enum TDM_LRJ lrj;
 	unsigned char enable;
 };

 struct jh7110_tdm_dev {
 	void __iomem *tdm_base;
 	struct device *dev;
 	struct clk_bulk_data clks[6];
 	struct reset_control *resets;

 	enum TDM_CLKPOL clkpolity;
 	enum TDM_ELM	elm;
 	enum TDM_SYNCM	syncm;
 	enum TDM_MASTER_SLAVE_MODE ms_mode;

 	struct tdm_chan_cfg tx;
 	struct tdm_chan_cfg rx;

 	u16 syncdiv;
 	u32 samplerate;
 	u32 pcmclk;

 	/* data related to DMA transfers b/w tdm and DMAC */
 	struct snd_dmaengine_dai_dma_data play_dma_data;
 	struct snd_dmaengine_dai_dma_data capture_dma_data;
 	u32 saved_pcmgbcr;
 	u32 saved_pcmtxcr;
 	u32 saved_pcmrxcr;
 	u32 saved_pcmdiv;
 };

 static inline u32 jh7110_tdm_readl(struct jh7110_tdm_dev *tdm, u16 reg)
 {
 	return readl_relaxed(tdm->tdm_base + reg);
 }

 static inline void jh7110_tdm_writel(struct jh7110_tdm_dev *tdm, u16 reg, u32 val)
 {
 	writel_relaxed(val, tdm->tdm_base + reg);
 }

 static void jh7110_tdm_save_context(struct jh7110_tdm_dev *tdm,
 				    struct snd_pcm_substream *substream)
 {
 	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
 		tdm->saved_pcmtxcr = jh7110_tdm_readl(tdm, TDM_PCMTXCR);
 	else
 		tdm->saved_pcmrxcr = jh7110_tdm_readl(tdm, TDM_PCMRXCR);
 }

 static void jh7110_tdm_start(struct jh7110_tdm_dev *tdm,
 			     struct snd_pcm_substream *substream)
 {
 	u32 data;

 	data = jh7110_tdm_readl(tdm, TDM_PCMGBCR);
 	jh7110_tdm_writel(tdm, TDM_PCMGBCR, data | PCMGBCR_ENABLE);

 	/* restore context */
 	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
 		jh7110_tdm_writel(tdm, TDM_PCMTXCR, tdm->saved_pcmtxcr | PCMTXCR_TXEN);
 	else
 		jh7110_tdm_writel(tdm, TDM_PCMRXCR, tdm->saved_pcmrxcr | PCMRXCR_RXEN);
 }

 static void jh7110_tdm_stop(struct jh7110_tdm_dev *tdm,
 			    struct snd_pcm_substream *substream)
 {
 	unsigned int val;

 	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
 		val = jh7110_tdm_readl(tdm, TDM_PCMTXCR);
 		val &= ~PCMTXCR_TXEN;
 		jh7110_tdm_writel(tdm, TDM_PCMTXCR, val);
 	} else {
 		val = jh7110_tdm_readl(tdm, TDM_PCMRXCR);
 		val &= ~PCMRXCR_RXEN;
 		jh7110_tdm_writel(tdm, TDM_PCMRXCR, val);
 	}
 }

 static int jh7110_tdm_syncdiv(struct jh7110_tdm_dev *tdm)
 {
 	u32 sl, sscale, syncdiv;

 	if (tdm->rx.sl >= tdm->tx.sl)
 		sl = tdm->rx.sl;
 	else
 		sl = tdm->tx.sl;

 	if (tdm->rx.sscale >= tdm->tx.sscale)
 		sscale = tdm->rx.sscale;
 	else
 		sscale = tdm->tx.sscale;

 	syncdiv = tdm->pcmclk / tdm->samplerate - 1;

 	if ((syncdiv + 1) < (sl * sscale)) {
 		dev_err(tdm->dev, "Failed to set syncdiv!\n");
 		return -EINVAL;
 	}

 	if (tdm->syncm == TDM_SYNCM_LONG &&
 	    (tdm->rx.sscale <= 1 || tdm->tx.sscale <= 1) &&
 	    ((syncdiv + 1) <= sl)) {
 		dev_err(tdm->dev, "Wrong syncdiv! It must be (syncdiv+1) > max[tx.sl, rx.sl]\n");
 		return -EINVAL;
 	}

 	jh7110_tdm_writel(tdm, TDM_PCMDIV, syncdiv);
 	return 0;
 }

 static int jh7110_tdm_config(struct jh7110_tdm_dev *tdm,
 			     struct snd_pcm_substream *substream)
 {
 	u32 datarx, datatx;
 	int ret;

 	ret = jh7110_tdm_syncdiv(tdm);
 	if (ret)
 		return ret;

 	datarx = (tdm->rx.ifl << IFL_BIT) |
 		  (tdm->rx.wl << WL_BIT) |
 		  (tdm->rx.sscale << SSCALE_BIT) |
 		  (tdm->rx.sl << SL_BIT) |
 		  (tdm->rx.lrj << LRJ_BIT);

 	datatx = (tdm->tx.ifl << IFL_BIT) |
 		  (tdm->tx.wl << WL_BIT) |
 		  (tdm->tx.sscale << SSCALE_BIT) |
 		  (tdm->tx.sl << SL_BIT) |
 		  (tdm->tx.lrj << LRJ_BIT);

 	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
 		jh7110_tdm_writel(tdm, TDM_PCMTXCR, datatx);
 	else
 		jh7110_tdm_writel(tdm, TDM_PCMRXCR, datarx);

 	return 0;
 }

 static void jh7110_tdm_clk_disable(struct jh7110_tdm_dev *tdm)
 {
 	clk_bulk_disable_unprepare(ARRAY_SIZE(tdm->clks), tdm->clks);
 }

 static int jh7110_tdm_clk_enable(struct jh7110_tdm_dev *tdm)
 {
 	int ret;

 	ret = clk_bulk_prepare_enable(ARRAY_SIZE(tdm->clks), tdm->clks);
 	if (ret) {
 		dev_err(tdm->dev, "Failed to enable tdm clocks\n");
 		return ret;
 	}

 	ret = reset_control_deassert(tdm->resets);
 	if (ret) {
 		dev_err(tdm->dev, "Failed to deassert tdm resets\n");
 		goto dis_tdm_clk;
 	}

 	/* select tdm_ext clock as the clock source for tdm */
 	ret = clk_set_parent(tdm->clks[5].clk, tdm->clks[4].clk);
 	if (ret) {
 		dev_err(tdm->dev, "Can't set extern clock source for clk_tdm\n");
 		goto dis_tdm_clk;
 	}

 	return 0;

 dis_tdm_clk:
 	clk_bulk_disable_unprepare(ARRAY_SIZE(tdm->clks), tdm->clks);

 	return ret;
 }

 static int jh7110_tdm_runtime_suspend(struct device *dev)
 {
 	struct jh7110_tdm_dev *tdm = dev_get_drvdata(dev);

 	jh7110_tdm_clk_disable(tdm);
 	return 0;
 }

 static int jh7110_tdm_runtime_resume(struct device *dev)
 {
 	struct jh7110_tdm_dev *tdm = dev_get_drvdata(dev);

 	return jh7110_tdm_clk_enable(tdm);
 }

 static int jh7110_tdm_system_suspend(struct device *dev)
 {
 	struct jh7110_tdm_dev *tdm = dev_get_drvdata(dev);

 	/* save context */
 	tdm->saved_pcmgbcr = jh7110_tdm_readl(tdm, TDM_PCMGBCR);
 	tdm->saved_pcmdiv = jh7110_tdm_readl(tdm, TDM_PCMDIV);

 	return pm_runtime_force_suspend(dev);
 }

 static int jh7110_tdm_system_resume(struct device *dev)
 {
 	struct jh7110_tdm_dev *tdm = dev_get_drvdata(dev);

 	/* restore context */
 	jh7110_tdm_writel(tdm, TDM_PCMGBCR, tdm->saved_pcmgbcr);
 	jh7110_tdm_writel(tdm, TDM_PCMDIV, tdm->saved_pcmdiv);

 	return pm_runtime_force_resume(dev);
 }

 static const struct snd_soc_component_driver jh7110_tdm_component = {
 	.name = "jh7110-tdm",
 };

 static int jh7110_tdm_startup(struct snd_pcm_substream *substream,
 			      struct snd_soc_dai *cpu_dai)
 {
 	struct snd_soc_pcm_runtime *rtd = asoc_substream_to_rtd(substream);
 	struct snd_soc_dai_link *dai_link = rtd->dai_link;

 	dai_link->trigger_stop = SND_SOC_TRIGGER_ORDER_LDC;

 	return 0;
 }

 static int jh7110_tdm_hw_params(struct snd_pcm_substream *substream,
 				struct snd_pcm_hw_params *params,
 				struct snd_soc_dai *dai)
 {
 	struct jh7110_tdm_dev *tdm = snd_soc_dai_get_drvdata(dai);
 	int chan_wl, chan_sl, chan_nr;
 	unsigned int data_width;
 	unsigned int dma_bus_width;
 	struct snd_dmaengine_dai_dma_data *dma_data = NULL;
 	int ret;

 	data_width = params_width(params);

 	tdm->samplerate = params_rate(params);
 	tdm->pcmclk = params_channels(params) * tdm->samplerate * data_width;

 	switch (params_format(params)) {
 	case SNDRV_PCM_FORMAT_S16_LE:
 		chan_wl = TDM_16BIT_WORD_LEN;
 		chan_sl = TDM_16BIT_SLOT_LEN;
 		dma_bus_width = DMA_SLAVE_BUSWIDTH_2_BYTES;
 		break;

 	case SNDRV_PCM_FORMAT_S32_LE:
 		chan_wl = TDM_32BIT_WORD_LEN;
 		chan_sl = TDM_32BIT_SLOT_LEN;
 		dma_bus_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
 		break;

 	default:
 		dev_err(tdm->dev, "tdm: unsupported PCM fmt");
 		return -EINVAL;
 	}

 	chan_nr = params_channels(params);
 	switch (chan_nr) {
 	case 1:
 	case 2:
 	case 4:
 	case 6:
 	case 8:
 		break;
 	default:
 		dev_err(tdm->dev, "channel not supported\n");
 		return -EINVAL;
 	}

 	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
 		tdm->tx.wl = chan_wl;
 		tdm->tx.sl = chan_sl;
 		tdm->tx.sscale = chan_nr;
 		tdm->play_dma_data.addr_width = dma_bus_width;
 		dma_data = &tdm->play_dma_data;
 	} else {
 		tdm->rx.wl = chan_wl;
 		tdm->rx.sl = chan_sl;
 		tdm->rx.sscale = chan_nr;
 		tdm->capture_dma_data.addr_width = dma_bus_width;
 		dma_data = &tdm->capture_dma_data;
 	}

 	snd_soc_dai_set_dma_data(dai, substream, dma_data);

 	ret = jh7110_tdm_config(tdm, substream);
 	if (ret)
 		return ret;

 	jh7110_tdm_save_context(tdm, substream);
 	return 0;
 }

 static int jh7110_tdm_trigger(struct snd_pcm_substream *substream,
 			      int cmd, struct snd_soc_dai *dai)
 {
 	struct jh7110_tdm_dev *tdm = snd_soc_dai_get_drvdata(dai);
 	int ret = 0;

 	switch (cmd) {
 	case SNDRV_PCM_TRIGGER_START:
 	case SNDRV_PCM_TRIGGER_RESUME:
 	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
 		jh7110_tdm_start(tdm, substream);
 		break;

 	case SNDRV_PCM_TRIGGER_STOP:
 	case SNDRV_PCM_TRIGGER_SUSPEND:
 	case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
 		jh7110_tdm_stop(tdm, substream);
 		break;
 	default:
 		ret = -EINVAL;
 		break;
 	}

 	return ret;
 }

 static int jh7110_tdm_set_dai_fmt(struct snd_soc_dai *cpu_dai,
 				  unsigned int fmt)
 {
 	struct jh7110_tdm_dev *tdm = snd_soc_dai_get_drvdata(cpu_dai);
 	unsigned int gbcr;

 	/* set master/slave audio interface */
 	switch (fmt & SND_SOC_DAIFMT_CLOCK_PROVIDER_MASK) {
 	case SND_SOC_DAIFMT_BP_FP:
 		/* cpu is master */
 		tdm->ms_mode = TDM_AS_MASTER;
 		break;
 	case SND_SOC_DAIFMT_BC_FC:
 		/* codec is master */
 		tdm->ms_mode = TDM_AS_SLAVE;
 		break;
 	case SND_SOC_DAIFMT_BC_FP:
 	case SND_SOC_DAIFMT_BP_FC:
 		return -EINVAL;
 	default:
 		dev_dbg(tdm->dev, "dwc : Invalid clock provider format\n");
 		return -EINVAL;
 	}

 	gbcr = (tdm->clkpolity << CLKPOL_BIT) |
 		(tdm->elm << ELM_BIT) |
 		(tdm->syncm << SYNCM_BIT) |
 		(tdm->ms_mode << MS_BIT);
 	jh7110_tdm_writel(tdm, TDM_PCMGBCR, gbcr);

 	return 0;
 }

 static int jh7110_tdm_dai_probe(struct snd_soc_dai *dai)
 {
 	struct jh7110_tdm_dev *tdm = snd_soc_dai_get_drvdata(dai);

 	snd_soc_dai_init_dma_data(dai, &tdm->play_dma_data, &tdm->capture_dma_data);
 	snd_soc_dai_set_drvdata(dai, tdm);
 	return 0;
 }

 static const struct snd_soc_dai_ops jh7110_tdm_dai_ops = {
 	.probe		= jh7110_tdm_dai_probe,
 	.startup	= jh7110_tdm_startup,
 	.hw_params	= jh7110_tdm_hw_params,
 	.trigger	= jh7110_tdm_trigger,
 	.set_fmt	= jh7110_tdm_set_dai_fmt,
 };

 #define JH7110_TDM_RATES	SNDRV_PCM_RATE_8000_48000

 #define JH7110_TDM_FORMATS	(SNDRV_PCM_FMTBIT_S16_LE | \
 				 SNDRV_PCM_FMTBIT_S32_LE)

 static struct snd_soc_dai_driver jh7110_tdm_dai = {
 	.name = "sf_tdm",
 	.id = 0,
 	.playback = {
 		.stream_name    = "Playback",
 		.channels_min   = 1,
 		.channels_max   = 8,
 		.rates          = JH7110_TDM_RATES,
 		.formats        = JH7110_TDM_FORMATS,
 	},
 	.capture = {
 		.stream_name    = "Capture",
 		.channels_min   = 1,
 		.channels_max   = 8,
 		.rates          = JH7110_TDM_RATES,
 		.formats        = JH7110_TDM_FORMATS,
 	},
 	.ops = &jh7110_tdm_dai_ops,
 	.symmetric_rate = 1,
 };

 static const struct snd_pcm_hardware jh7110_pcm_hardware = {
 	.info			= (SNDRV_PCM_INFO_MMAP		|
 				   SNDRV_PCM_INFO_MMAP_VALID	|
 				   SNDRV_PCM_INFO_PAUSE		|
 				   SNDRV_PCM_INFO_RESUME	|
 				   SNDRV_PCM_INFO_INTERLEAVED	|
 				   SNDRV_PCM_INFO_BLOCK_TRANSFER),
 	.buffer_bytes_max	= 192512,
 	.period_bytes_min	= 4096,
 	.period_bytes_max	= 32768,
 	.periods_min		= 1,
 	.periods_max		= 48,
 	.fifo_size		= 16,
 };

 static const struct snd_dmaengine_pcm_config jh7110_dmaengine_pcm_config = {
 	.pcm_hardware = &jh7110_pcm_hardware,
 	.prepare_slave_config = snd_dmaengine_pcm_prepare_slave_config,
 	.prealloc_buffer_size = 192512,
 };

 static void jh7110_tdm_init_params(struct jh7110_tdm_dev *tdm)
 {
 	tdm->clkpolity = TDM_TX_RASING_RX_FALLING;
 	tdm->elm = TDM_ELM_LATE;
 	tdm->syncm = TDM_SYNCM_SHORT;

 	tdm->rx.ifl = TDM_FIFO_HALF;
 	tdm->tx.ifl = TDM_FIFO_HALF;
 	tdm->rx.wl = TDM_16BIT_WORD_LEN;
 	tdm->tx.wl = TDM_16BIT_WORD_LEN;
 	tdm->rx.sscale = 2;
 	tdm->tx.sscale = 2;
 	tdm->rx.lrj = TDM_LEFT_JUSTIFT;
 	tdm->tx.lrj = TDM_LEFT_JUSTIFT;

 	tdm->play_dma_data.addr = JH7110_TDM_FIFO;
 	tdm->play_dma_data.addr_width = DMA_SLAVE_BUSWIDTH_2_BYTES;
 	tdm->play_dma_data.fifo_size = JH7110_TDM_FIFO_DEPTH / 2;
 	tdm->play_dma_data.maxburst = 16;

 	tdm->capture_dma_data.addr = JH7110_TDM_FIFO;
 	tdm->capture_dma_data.addr_width = DMA_SLAVE_BUSWIDTH_2_BYTES;
 	tdm->capture_dma_data.fifo_size = JH7110_TDM_FIFO_DEPTH / 2;
 	tdm->capture_dma_data.maxburst = 8;
 }

 static int jh7110_tdm_clk_reset_get(struct platform_device *pdev,
 				    struct jh7110_tdm_dev *tdm)
 {
 	int ret;

 	tdm->clks[0].id = "mclk_inner";
 	tdm->clks[1].id = "tdm_ahb";
 	tdm->clks[2].id = "tdm_apb";
 	tdm->clks[3].id = "tdm_internal";
 	tdm->clks[4].id = "tdm_ext";
 	tdm->clks[5].id = "tdm";

 	ret = devm_clk_bulk_get(&pdev->dev, ARRAY_SIZE(tdm->clks), tdm->clks);
 	if (ret) {
 		dev_err(&pdev->dev, "Failed to get tdm clocks\n");
 		return ret;
 	}

 	tdm->resets = devm_reset_control_array_get_exclusive(&pdev->dev);
 	if (IS_ERR(tdm->resets)) {
 		dev_err(&pdev->dev, "Failed to get tdm resets\n");
 		return PTR_ERR(tdm->resets);
 	}

 	return 0;
 }

 static int jh7110_tdm_probe(struct platform_device *pdev)
 {
 	struct jh7110_tdm_dev *tdm;
 	int ret;

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

 	tdm->tdm_base = devm_platform_ioremap_resource(pdev, 0);
 	if (IS_ERR(tdm->tdm_base))
 		return PTR_ERR(tdm->tdm_base);

 	tdm->dev = &pdev->dev;

 	ret = jh7110_tdm_clk_reset_get(pdev, tdm);
 	if (ret) {
 		dev_err(&pdev->dev, "Failed to enable audio-tdm clock\n");
 		return ret;
 	}

 	jh7110_tdm_init_params(tdm);

 	dev_set_drvdata(&pdev->dev, tdm);
 	ret = devm_snd_soc_register_component(&pdev->dev, &jh7110_tdm_component,
 					      &jh7110_tdm_dai, 1);
 	if (ret) {
 		dev_err(&pdev->dev, "Failed to register dai\n");
 		return ret;
 	}

 	ret = devm_snd_dmaengine_pcm_register(&pdev->dev,
 					      &jh7110_dmaengine_pcm_config,
 					      SND_DMAENGINE_PCM_FLAG_COMPAT);
 	if (ret) {
 		dev_err(&pdev->dev, "Could not register pcm: %d\n", ret);
 		return ret;
 	}

 	pm_runtime_enable(&pdev->dev);
 	if (!pm_runtime_enabled(&pdev->dev)) {
 		ret = jh7110_tdm_runtime_resume(&pdev->dev);
 		if (ret)
 			goto err_pm_disable;
 	}

 	return 0;

 err_pm_disable:
 	pm_runtime_disable(&pdev->dev);

 	return ret;
 }

 static void jh7110_tdm_dev_remove(struct platform_device *pdev)
 {
 	pm_runtime_disable(&pdev->dev);
 }

 static const struct of_device_id jh7110_tdm_of_match[] = {
 	{ .compatible = "starfive,jh7110-tdm", },
 	{}
 };

 MODULE_DEVICE_TABLE(of, jh7110_tdm_of_match);

 static const struct dev_pm_ops jh7110_tdm_pm_ops = {
 	RUNTIME_PM_OPS(jh7110_tdm_runtime_suspend,
 		       jh7110_tdm_runtime_resume, NULL)
 	SYSTEM_SLEEP_PM_OPS(jh7110_tdm_system_suspend,
 			    jh7110_tdm_system_resume)
 };

 static struct platform_driver jh7110_tdm_driver = {
 	.driver = {
 		.name = "jh7110-tdm",
 		.of_match_table = jh7110_tdm_of_match,
 		.pm = pm_ptr(&jh7110_tdm_pm_ops),
 	},
 	.probe = jh7110_tdm_probe,
 	.remove_new = jh7110_tdm_dev_remove,
 };
 module_platform_driver(jh7110_tdm_driver);

 MODULE_DESCRIPTION("StarFive JH7110 TDM ASoC Driver");
 MODULE_AUTHOR("Walker Chen <walker.chen@starfivetech.com>");
 MODULE_LICENSE("GPL");
	// SPDX-License-Identifier: GPL-2.0
	/*
	* jh7110_tdm.c -- StarFive JH7110 TDM driver
	*
	* Copyright (C) 2023 StarFive Technology Co., Ltd.
	*
	* Author: Walker Chen <walker.chen@starfivetech.com>
	*/

	#include <linux/clk.h>
	#include <linux/device.h>
	#include <linux/dmaengine.h>
	#include <linux/module.h>
	#include <linux/of_irq.h>
	#include <linux/of_platform.h>
	#include <linux/pm_runtime.h>
	#include <linux/regmap.h>
	#include <linux/reset.h>
	#include <linux/types.h>
	#include <sound/dmaengine_pcm.h>
	#include <sound/initval.h>
	#include <sound/pcm.h>
	#include <sound/pcm_params.h>
	#include <sound/soc.h>
	#include <sound/soc-dai.h>

	#define TDM_PCMGBCR 0x00
	#define PCMGBCR_ENABLE BIT(0)
	#define CLKPOL_BIT 5
	#define ELM_BIT 3
	#define SYNCM_BIT 2
	#define MS_BIT 1
	#define TDM_PCMTXCR 0x04
	#define PCMTXCR_TXEN BIT(0)
	#define IFL_BIT 11
	#define WL_BIT 8
	#define SSCALE_BIT 4
	#define SL_BIT 2
	#define LRJ_BIT 1
	#define TDM_PCMRXCR 0x08
	#define PCMRXCR_RXEN BIT(0)
	#define TDM_PCMDIV 0x0c

	#define JH7110_TDM_FIFO 0x170c0000
	#define JH7110_TDM_FIFO_DEPTH 32

	enum TDM_MASTER_SLAVE_MODE {
	TDM_AS_MASTER = 0,
	TDM_AS_SLAVE,
	};

	enum TDM_CLKPOL {
	/* tx raising and rx falling */
	TDM_TX_RASING_RX_FALLING = 0,
	/* tx falling and rx raising */
	TDM_TX_FALLING_RX_RASING,
	};

	enum TDM_ELM {
	/* only work while SYNCM=0 */
	TDM_ELM_LATE = 0,
	TDM_ELM_EARLY,
	};

	enum TDM_SYNCM {
	/* short frame sync */
	TDM_SYNCM_SHORT = 0,
	/* long frame sync */
	TDM_SYNCM_LONG,
	};

	enum TDM_IFL {
	/* FIFO to send or received : half-1/2, Quarter-1/4 */
	TDM_FIFO_HALF = 0,
	TDM_FIFO_QUARTER,
	};

	enum TDM_WL {
	/* send or received word length */
	TDM_8BIT_WORD_LEN = 0,
	TDM_16BIT_WORD_LEN,
	TDM_20BIT_WORD_LEN,
	TDM_24BIT_WORD_LEN,
	TDM_32BIT_WORD_LEN,
	};

	enum TDM_SL {
	/* send or received slot length */
	TDM_8BIT_SLOT_LEN = 0,
	TDM_16BIT_SLOT_LEN,
	TDM_32BIT_SLOT_LEN,
	};

	enum TDM_LRJ {
	/* left-justify or right-justify */
	TDM_RIGHT_JUSTIFY = 0,
	TDM_LEFT_JUSTIFT,
	};

	struct tdm_chan_cfg {
	enum TDM_IFL ifl;
	enum TDM_WL wl;
	unsigned char sscale;
	enum TDM_SL sl;
	enum TDM_LRJ lrj;
	unsigned char enable;
	};

	struct jh7110_tdm_dev {
	void __iomem *tdm_base;
	struct device *dev;
	struct clk_bulk_data clks[6];
	struct reset_control *resets;

	enum TDM_CLKPOL clkpolity;
	enum TDM_ELM elm;
	enum TDM_SYNCM syncm;
	enum TDM_MASTER_SLAVE_MODE ms_mode;

	struct tdm_chan_cfg tx;
	struct tdm_chan_cfg rx;

	u16 syncdiv;
	u32 samplerate;
	u32 pcmclk;

	/* data related to DMA transfers b/w tdm and DMAC */
	struct snd_dmaengine_dai_dma_data play_dma_data;
	struct snd_dmaengine_dai_dma_data capture_dma_data;
	u32 saved_pcmgbcr;
	u32 saved_pcmtxcr;
	u32 saved_pcmrxcr;
	u32 saved_pcmdiv;
	};

	static inline u32 jh7110_tdm_readl(struct jh7110_tdm_dev *tdm, u16 reg)
	{
	return readl_relaxed(tdm->tdm_base + reg);
	}

	static inline void jh7110_tdm_writel(struct jh7110_tdm_dev *tdm, u16 reg, u32 val)
	{
	writel_relaxed(val, tdm->tdm_base + reg);
	}

	static void jh7110_tdm_save_context(struct jh7110_tdm_dev *tdm,
	struct snd_pcm_substream *substream)
	{
	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
	tdm->saved_pcmtxcr = jh7110_tdm_readl(tdm, TDM_PCMTXCR);
	else
	tdm->saved_pcmrxcr = jh7110_tdm_readl(tdm, TDM_PCMRXCR);
	}

	static void jh7110_tdm_start(struct jh7110_tdm_dev *tdm,
	struct snd_pcm_substream *substream)
	{
	u32 data;

	data = jh7110_tdm_readl(tdm, TDM_PCMGBCR);
	jh7110_tdm_writel(tdm, TDM_PCMGBCR, data \| PCMGBCR_ENABLE);

	/* restore context */
	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
	jh7110_tdm_writel(tdm, TDM_PCMTXCR, tdm->saved_pcmtxcr \| PCMTXCR_TXEN);
	else
	jh7110_tdm_writel(tdm, TDM_PCMRXCR, tdm->saved_pcmrxcr \| PCMRXCR_RXEN);
	}

	static void jh7110_tdm_stop(struct jh7110_tdm_dev *tdm,
	struct snd_pcm_substream *substream)
	{
	unsigned int val;

	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
	val = jh7110_tdm_readl(tdm, TDM_PCMTXCR);
	val &= ~PCMTXCR_TXEN;
	jh7110_tdm_writel(tdm, TDM_PCMTXCR, val);
	} else {
	val = jh7110_tdm_readl(tdm, TDM_PCMRXCR);
	val &= ~PCMRXCR_RXEN;
	jh7110_tdm_writel(tdm, TDM_PCMRXCR, val);
	}
	}

	static int jh7110_tdm_syncdiv(struct jh7110_tdm_dev *tdm)
	{
	u32 sl, sscale, syncdiv;

	if (tdm->rx.sl >= tdm->tx.sl)
	sl = tdm->rx.sl;
	else
	sl = tdm->tx.sl;

	if (tdm->rx.sscale >= tdm->tx.sscale)
	sscale = tdm->rx.sscale;
	else
	sscale = tdm->tx.sscale;

	syncdiv = tdm->pcmclk / tdm->samplerate - 1;

	if ((syncdiv + 1) < (sl * sscale)) {
	dev_err(tdm->dev, "Failed to set syncdiv!\n");
	return -EINVAL;
	}

	if (tdm->syncm == TDM_SYNCM_LONG &&
	(tdm->rx.sscale <= 1 \|\| tdm->tx.sscale <= 1) &&
	((syncdiv + 1) <= sl)) {
	dev_err(tdm->dev, "Wrong syncdiv! It must be (syncdiv+1) > max[tx.sl, rx.sl]\n");
	return -EINVAL;
	}

	jh7110_tdm_writel(tdm, TDM_PCMDIV, syncdiv);
	return 0;
	}

	static int jh7110_tdm_config(struct jh7110_tdm_dev *tdm,
	struct snd_pcm_substream *substream)
	{
	u32 datarx, datatx;
	int ret;

	ret = jh7110_tdm_syncdiv(tdm);
	if (ret)
	return ret;

	datarx = (tdm->rx.ifl << IFL_BIT) \|
	(tdm->rx.wl << WL_BIT) \|
	(tdm->rx.sscale << SSCALE_BIT) \|
	(tdm->rx.sl << SL_BIT) \|
	(tdm->rx.lrj << LRJ_BIT);

	datatx = (tdm->tx.ifl << IFL_BIT) \|
	(tdm->tx.wl << WL_BIT) \|
	(tdm->tx.sscale << SSCALE_BIT) \|
	(tdm->tx.sl << SL_BIT) \|
	(tdm->tx.lrj << LRJ_BIT);

	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
	jh7110_tdm_writel(tdm, TDM_PCMTXCR, datatx);
	else
	jh7110_tdm_writel(tdm, TDM_PCMRXCR, datarx);

	return 0;
	}

	static void jh7110_tdm_clk_disable(struct jh7110_tdm_dev *tdm)
	{
	clk_bulk_disable_unprepare(ARRAY_SIZE(tdm->clks), tdm->clks);
	}

	static int jh7110_tdm_clk_enable(struct jh7110_tdm_dev *tdm)
	{
	int ret;

	ret = clk_bulk_prepare_enable(ARRAY_SIZE(tdm->clks), tdm->clks);
	if (ret) {
	dev_err(tdm->dev, "Failed to enable tdm clocks\n");
	return ret;
	}

	ret = reset_control_deassert(tdm->resets);
	if (ret) {
	dev_err(tdm->dev, "Failed to deassert tdm resets\n");
	goto dis_tdm_clk;
	}

	/* select tdm_ext clock as the clock source for tdm */
	ret = clk_set_parent(tdm->clks[5].clk, tdm->clks[4].clk);
	if (ret) {
	dev_err(tdm->dev, "Can't set extern clock source for clk_tdm\n");
	goto dis_tdm_clk;
	}

	return 0;

	dis_tdm_clk:
	clk_bulk_disable_unprepare(ARRAY_SIZE(tdm->clks), tdm->clks);

	return ret;
	}

	static int jh7110_tdm_runtime_suspend(struct device *dev)
	{
	struct jh7110_tdm_dev *tdm = dev_get_drvdata(dev);

	jh7110_tdm_clk_disable(tdm);
	return 0;
	}

	static int jh7110_tdm_runtime_resume(struct device *dev)
	{
	struct jh7110_tdm_dev *tdm = dev_get_drvdata(dev);

	return jh7110_tdm_clk_enable(tdm);
	}

	static int jh7110_tdm_system_suspend(struct device *dev)
	{
	struct jh7110_tdm_dev *tdm = dev_get_drvdata(dev);

	/* save context */
	tdm->saved_pcmgbcr = jh7110_tdm_readl(tdm, TDM_PCMGBCR);
	tdm->saved_pcmdiv = jh7110_tdm_readl(tdm, TDM_PCMDIV);

	return pm_runtime_force_suspend(dev);
	}

	static int jh7110_tdm_system_resume(struct device *dev)
	{
	struct jh7110_tdm_dev *tdm = dev_get_drvdata(dev);

	/* restore context */
	jh7110_tdm_writel(tdm, TDM_PCMGBCR, tdm->saved_pcmgbcr);
	jh7110_tdm_writel(tdm, TDM_PCMDIV, tdm->saved_pcmdiv);

	return pm_runtime_force_resume(dev);
	}

	static const struct snd_soc_component_driver jh7110_tdm_component = {
	.name = "jh7110-tdm",
	};

	static int jh7110_tdm_startup(struct snd_pcm_substream *substream,
	struct snd_soc_dai *cpu_dai)
	{
	struct snd_soc_pcm_runtime *rtd = asoc_substream_to_rtd(substream);
	struct snd_soc_dai_link *dai_link = rtd->dai_link;

	dai_link->trigger_stop = SND_SOC_TRIGGER_ORDER_LDC;

	return 0;
	}

	static int jh7110_tdm_hw_params(struct snd_pcm_substream *substream,
	struct snd_pcm_hw_params *params,
	struct snd_soc_dai *dai)
	{
	struct jh7110_tdm_dev *tdm = snd_soc_dai_get_drvdata(dai);
	int chan_wl, chan_sl, chan_nr;
	unsigned int data_width;
	unsigned int dma_bus_width;
	struct snd_dmaengine_dai_dma_data *dma_data = NULL;
	int ret;

	data_width = params_width(params);

	tdm->samplerate = params_rate(params);
	tdm->pcmclk = params_channels(params) * tdm->samplerate * data_width;

	switch (params_format(params)) {
	case SNDRV_PCM_FORMAT_S16_LE:
	chan_wl = TDM_16BIT_WORD_LEN;
	chan_sl = TDM_16BIT_SLOT_LEN;
	dma_bus_width = DMA_SLAVE_BUSWIDTH_2_BYTES;
	break;

	case SNDRV_PCM_FORMAT_S32_LE:
	chan_wl = TDM_32BIT_WORD_LEN;
	chan_sl = TDM_32BIT_SLOT_LEN;
	dma_bus_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
	break;

	default:
	dev_err(tdm->dev, "tdm: unsupported PCM fmt");
	return -EINVAL;
	}

	chan_nr = params_channels(params);
	switch (chan_nr) {
	case 1:
	case 2:
	case 4:
	case 6:
	case 8:
	break;
	default:
	dev_err(tdm->dev, "channel not supported\n");
	return -EINVAL;
	}

	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
	tdm->tx.wl = chan_wl;
	tdm->tx.sl = chan_sl;
	tdm->tx.sscale = chan_nr;
	tdm->play_dma_data.addr_width = dma_bus_width;
	dma_data = &tdm->play_dma_data;
	} else {
	tdm->rx.wl = chan_wl;
	tdm->rx.sl = chan_sl;
	tdm->rx.sscale = chan_nr;
	tdm->capture_dma_data.addr_width = dma_bus_width;
	dma_data = &tdm->capture_dma_data;
	}

	snd_soc_dai_set_dma_data(dai, substream, dma_data);

	ret = jh7110_tdm_config(tdm, substream);
	if (ret)
	return ret;

	jh7110_tdm_save_context(tdm, substream);
	return 0;
	}

	static int jh7110_tdm_trigger(struct snd_pcm_substream *substream,
	int cmd, struct snd_soc_dai *dai)
	{
	struct jh7110_tdm_dev *tdm = snd_soc_dai_get_drvdata(dai);
	int ret = 0;

	switch (cmd) {
	case SNDRV_PCM_TRIGGER_START:
	case SNDRV_PCM_TRIGGER_RESUME:
	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
	jh7110_tdm_start(tdm, substream);
	break;

	case SNDRV_PCM_TRIGGER_STOP:
	case SNDRV_PCM_TRIGGER_SUSPEND:
	case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
	jh7110_tdm_stop(tdm, substream);
	break;
	default:
	ret = -EINVAL;
	break;
	}

	return ret;
	}

	static int jh7110_tdm_set_dai_fmt(struct snd_soc_dai *cpu_dai,
	unsigned int fmt)
	{
	struct jh7110_tdm_dev *tdm = snd_soc_dai_get_drvdata(cpu_dai);
	unsigned int gbcr;

	/* set master/slave audio interface */
	switch (fmt & SND_SOC_DAIFMT_CLOCK_PROVIDER_MASK) {
	case SND_SOC_DAIFMT_BP_FP:
	/* cpu is master */
	tdm->ms_mode = TDM_AS_MASTER;
	break;
	case SND_SOC_DAIFMT_BC_FC:
	/* codec is master */
	tdm->ms_mode = TDM_AS_SLAVE;
	break;
	case SND_SOC_DAIFMT_BC_FP:
	case SND_SOC_DAIFMT_BP_FC:
	return -EINVAL;
	default:
	dev_dbg(tdm->dev, "dwc : Invalid clock provider format\n");
	return -EINVAL;
	}

	gbcr = (tdm->clkpolity << CLKPOL_BIT) \|
	(tdm->elm << ELM_BIT) \|
	(tdm->syncm << SYNCM_BIT) \|
	(tdm->ms_mode << MS_BIT);
	jh7110_tdm_writel(tdm, TDM_PCMGBCR, gbcr);

	return 0;
	}

	static int jh7110_tdm_dai_probe(struct snd_soc_dai *dai)
	{
	struct jh7110_tdm_dev *tdm = snd_soc_dai_get_drvdata(dai);

	snd_soc_dai_init_dma_data(dai, &tdm->play_dma_data, &tdm->capture_dma_data);
	snd_soc_dai_set_drvdata(dai, tdm);
	return 0;
	}

	static const struct snd_soc_dai_ops jh7110_tdm_dai_ops = {
	.probe = jh7110_tdm_dai_probe,
	.startup = jh7110_tdm_startup,
	.hw_params = jh7110_tdm_hw_params,
	.trigger = jh7110_tdm_trigger,
	.set_fmt = jh7110_tdm_set_dai_fmt,
	};

	#define JH7110_TDM_RATES SNDRV_PCM_RATE_8000_48000

	#define JH7110_TDM_FORMATS (SNDRV_PCM_FMTBIT_S16_LE \| \
	SNDRV_PCM_FMTBIT_S32_LE)

	static struct snd_soc_dai_driver jh7110_tdm_dai = {
	.name = "sf_tdm",
	.id = 0,
	.playback = {
	.stream_name = "Playback",
	.channels_min = 1,
	.channels_max = 8,
	.rates = JH7110_TDM_RATES,
	.formats = JH7110_TDM_FORMATS,
	},
	.capture = {
	.stream_name = "Capture",
	.channels_min = 1,
	.channels_max = 8,
	.rates = JH7110_TDM_RATES,
	.formats = JH7110_TDM_FORMATS,
	},
	.ops = &jh7110_tdm_dai_ops,
	.symmetric_rate = 1,
	};

	static const struct snd_pcm_hardware jh7110_pcm_hardware = {
	.info = (SNDRV_PCM_INFO_MMAP \|
	SNDRV_PCM_INFO_MMAP_VALID \|
	SNDRV_PCM_INFO_PAUSE \|
	SNDRV_PCM_INFO_RESUME \|
	SNDRV_PCM_INFO_INTERLEAVED \|
	SNDRV_PCM_INFO_BLOCK_TRANSFER),
	.buffer_bytes_max = 192512,
	.period_bytes_min = 4096,
	.period_bytes_max = 32768,
	.periods_min = 1,
	.periods_max = 48,
	.fifo_size = 16,
	};

	static const struct snd_dmaengine_pcm_config jh7110_dmaengine_pcm_config = {
	.pcm_hardware = &jh7110_pcm_hardware,
	.prepare_slave_config = snd_dmaengine_pcm_prepare_slave_config,
	.prealloc_buffer_size = 192512,
	};

	static void jh7110_tdm_init_params(struct jh7110_tdm_dev *tdm)
	{
	tdm->clkpolity = TDM_TX_RASING_RX_FALLING;
	tdm->elm = TDM_ELM_LATE;
	tdm->syncm = TDM_SYNCM_SHORT;

	tdm->rx.ifl = TDM_FIFO_HALF;
	tdm->tx.ifl = TDM_FIFO_HALF;
	tdm->rx.wl = TDM_16BIT_WORD_LEN;
	tdm->tx.wl = TDM_16BIT_WORD_LEN;
	tdm->rx.sscale = 2;
	tdm->tx.sscale = 2;
	tdm->rx.lrj = TDM_LEFT_JUSTIFT;
	tdm->tx.lrj = TDM_LEFT_JUSTIFT;

	tdm->play_dma_data.addr = JH7110_TDM_FIFO;
	tdm->play_dma_data.addr_width = DMA_SLAVE_BUSWIDTH_2_BYTES;
	tdm->play_dma_data.fifo_size = JH7110_TDM_FIFO_DEPTH / 2;
	tdm->play_dma_data.maxburst = 16;

	tdm->capture_dma_data.addr = JH7110_TDM_FIFO;
	tdm->capture_dma_data.addr_width = DMA_SLAVE_BUSWIDTH_2_BYTES;
	tdm->capture_dma_data.fifo_size = JH7110_TDM_FIFO_DEPTH / 2;
	tdm->capture_dma_data.maxburst = 8;
	}

	static int jh7110_tdm_clk_reset_get(struct platform_device *pdev,
	struct jh7110_tdm_dev *tdm)
	{
	int ret;

	tdm->clks[0].id = "mclk_inner";
	tdm->clks[1].id = "tdm_ahb";
	tdm->clks[2].id = "tdm_apb";
	tdm->clks[3].id = "tdm_internal";
	tdm->clks[4].id = "tdm_ext";
	tdm->clks[5].id = "tdm";

	ret = devm_clk_bulk_get(&pdev->dev, ARRAY_SIZE(tdm->clks), tdm->clks);
	if (ret) {
	dev_err(&pdev->dev, "Failed to get tdm clocks\n");
	return ret;
	}

	tdm->resets = devm_reset_control_array_get_exclusive(&pdev->dev);
	if (IS_ERR(tdm->resets)) {
	dev_err(&pdev->dev, "Failed to get tdm resets\n");
	return PTR_ERR(tdm->resets);
	}

	return 0;
	}

	static int jh7110_tdm_probe(struct platform_device *pdev)
	{
	struct jh7110_tdm_dev *tdm;
	int ret;

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

	tdm->tdm_base = devm_platform_ioremap_resource(pdev, 0);
	if (IS_ERR(tdm->tdm_base))
	return PTR_ERR(tdm->tdm_base);

	tdm->dev = &pdev->dev;

	ret = jh7110_tdm_clk_reset_get(pdev, tdm);
	if (ret) {
	dev_err(&pdev->dev, "Failed to enable audio-tdm clock\n");
	return ret;
	}

	jh7110_tdm_init_params(tdm);

	dev_set_drvdata(&pdev->dev, tdm);
	ret = devm_snd_soc_register_component(&pdev->dev, &jh7110_tdm_component,
	&jh7110_tdm_dai, 1);
	if (ret) {
	dev_err(&pdev->dev, "Failed to register dai\n");
	return ret;
	}

	ret = devm_snd_dmaengine_pcm_register(&pdev->dev,
	&jh7110_dmaengine_pcm_config,
	SND_DMAENGINE_PCM_FLAG_COMPAT);
	if (ret) {
	dev_err(&pdev->dev, "Could not register pcm: %d\n", ret);
	return ret;
	}

	pm_runtime_enable(&pdev->dev);
	if (!pm_runtime_enabled(&pdev->dev)) {
	ret = jh7110_tdm_runtime_resume(&pdev->dev);
	if (ret)
	goto err_pm_disable;
	}

	return 0;

	err_pm_disable:
	pm_runtime_disable(&pdev->dev);

	return ret;
	}

	static void jh7110_tdm_dev_remove(struct platform_device *pdev)
	{
	pm_runtime_disable(&pdev->dev);
	}

	static const struct of_device_id jh7110_tdm_of_match[] = {
	{ .compatible = "starfive,jh7110-tdm", },
	{}
	};

	MODULE_DEVICE_TABLE(of, jh7110_tdm_of_match);

	static const struct dev_pm_ops jh7110_tdm_pm_ops = {
	RUNTIME_PM_OPS(jh7110_tdm_runtime_suspend,
	jh7110_tdm_runtime_resume, NULL)
	SYSTEM_SLEEP_PM_OPS(jh7110_tdm_system_suspend,
	jh7110_tdm_system_resume)
	};

	static struct platform_driver jh7110_tdm_driver = {
	.driver = {
	.name = "jh7110-tdm",
	.of_match_table = jh7110_tdm_of_match,
	.pm = pm_ptr(&jh7110_tdm_pm_ops),
	},
	.probe = jh7110_tdm_probe,
	.remove_new = jh7110_tdm_dev_remove,
	};
	module_platform_driver(jh7110_tdm_driver);

	MODULE_DESCRIPTION("StarFive JH7110 TDM ASoC Driver");
	MODULE_AUTHOR("Walker Chen <walker.chen@starfivetech.com>");
	MODULE_LICENSE("GPL");