Resguardo inicial

linux-7.2.3/sound/soc/cirrus/Kconfig

@@ -0,0 +1,36 @@
+# SPDX-License-Identifier: GPL-2.0-only
+menu "Cirrus Logic"
+
+config SND_EP93XX_SOC
+	tristate "SoC Audio support for the Cirrus Logic EP93xx series"
+	depends on ARCH_EP93XX || COMPILE_TEST
+	select SND_SOC_GENERIC_DMAENGINE_PCM
+	help
+	  Say Y or M if you want to add support for codecs attached to
+	  the EP93xx I2S or AC97 interfaces.
+
+config SND_EP93XX_SOC_I2S
+	tristate "I2S controller support for the Cirrus Logic EP93xx series"
+	depends on SND_EP93XX_SOC
+	help
+	  Say Y or M if you want to add support for codecs attached to
+	  the EP93xx I2S interface.
+
+if SND_EP93XX_SOC_I2S
+
+config SND_EP93XX_SOC_I2S_WATCHDOG
+	bool "IRQ based underflow watchdog workaround"
+	default y
+	help
+	  I2S controller on EP93xx seems to have undocumented HW issue.
+	  Underflow of internal I2S controller FIFO could confuse the
+	  state machine and the whole stream can be shifted by one byte
+	  until I2S is disabled. This option enables IRQ based watchdog
+	  which disables and re-enables I2S in case of underflow and
+	  fills FIFO with zeroes.
+
+	  If you are unsure how to answer this question, answer Y.
+
+endif # if SND_EP93XX_SOC_I2S
+
+endmenu

linux-7.2.3/sound/soc/cirrus/Makefile

@@ -0,0 +1,8 @@
+# SPDX-License-Identifier: GPL-2.0
+# EP93xx Platform Support
+snd-soc-ep93xx-y				:= ep93xx-pcm.o
+snd-soc-ep93xx-i2s-y	 			:= ep93xx-i2s.o
+
+obj-$(CONFIG_SND_EP93XX_SOC)			+= snd-soc-ep93xx.o
+obj-$(CONFIG_SND_EP93XX_SOC_I2S)		+= snd-soc-ep93xx-i2s.o
+

linux-7.2.3/sound/soc/cirrus/ep93xx-i2s.c

@@ -0,0 +1,533 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * linux/sound/soc/ep93xx-i2s.c
+ * EP93xx I2S driver
+ *
+ * Copyright (C) 2010 Ryan Mallon
+ *
+ * Based on the original driver by:
+ *   Copyright (C) 2007 Chase Douglas <chasedouglas@gmail>
+ *   Copyright (C) 2006 Lennert Buytenhek <buytenh@wantstofly.org>
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/clk.h>
+#include <linux/io.h>
+#include <linux/of.h>
+
+#include <sound/core.h>
+#include <sound/dmaengine_pcm.h>
+#include <sound/pcm.h>
+#include <sound/pcm_params.h>
+#include <sound/initval.h>
+#include <sound/soc.h>
+
+#include <linux/soc/cirrus/ep93xx.h>
+
+#include "ep93xx-pcm.h"
+
+#define EP93XX_I2S_TXCLKCFG		0x00
+#define EP93XX_I2S_RXCLKCFG		0x04
+#define EP93XX_I2S_GLSTS		0x08
+#define EP93XX_I2S_GLCTRL		0x0C
+
+#define EP93XX_I2S_I2STX0LFT		0x10
+#define EP93XX_I2S_I2STX0RT		0x14
+
+#define EP93XX_I2S_TXLINCTRLDATA	0x28
+#define EP93XX_I2S_TXCTRL		0x2C
+#define EP93XX_I2S_TXWRDLEN		0x30
+#define EP93XX_I2S_TX0EN		0x34
+
+#define EP93XX_I2S_RXLINCTRLDATA	0x58
+#define EP93XX_I2S_RXCTRL		0x5C
+#define EP93XX_I2S_RXWRDLEN		0x60
+#define EP93XX_I2S_RX0EN		0x64
+
+#define EP93XX_I2S_WRDLEN_16		(0 << 0)
+#define EP93XX_I2S_WRDLEN_24		(1 << 0)
+#define EP93XX_I2S_WRDLEN_32		(2 << 0)
+
+#define EP93XX_I2S_RXLINCTRLDATA_R_JUST	BIT(1) /* Right justify */
+
+#define EP93XX_I2S_TXLINCTRLDATA_R_JUST	BIT(2) /* Right justify */
+
+/*
+ * Transmit empty interrupt level select:
+ * 0 - Generate interrupt when FIFO is half empty
+ * 1 - Generate interrupt when FIFO is empty
+ */
+#define EP93XX_I2S_TXCTRL_TXEMPTY_LVL	BIT(0)
+#define EP93XX_I2S_TXCTRL_TXUFIE	BIT(1) /* Transmit interrupt enable */
+
+#define EP93XX_I2S_CLKCFG_LRS		(1 << 0) /* lrclk polarity */
+#define EP93XX_I2S_CLKCFG_CKP		(1 << 1) /* Bit clock polarity */
+#define EP93XX_I2S_CLKCFG_REL		(1 << 2) /* First bit transition */
+#define EP93XX_I2S_CLKCFG_MASTER	(1 << 3) /* Master mode */
+#define EP93XX_I2S_CLKCFG_NBCG		(1 << 4) /* Not bit clock gating */
+
+#define EP93XX_I2S_GLSTS_TX0_FIFO_FULL	BIT(12)
+
+struct ep93xx_i2s_info {
+	struct clk			*mclk;
+	struct clk			*sclk;
+	struct clk			*lrclk;
+	void __iomem			*regs;
+	struct snd_dmaengine_dai_dma_data dma_params_rx;
+	struct snd_dmaengine_dai_dma_data dma_params_tx;
+};
+
+static inline void ep93xx_i2s_write_reg(struct ep93xx_i2s_info *info,
+					unsigned reg, unsigned val)
+{
+	__raw_writel(val, info->regs + reg);
+}
+
+static inline unsigned ep93xx_i2s_read_reg(struct ep93xx_i2s_info *info,
+					   unsigned reg)
+{
+	return __raw_readl(info->regs + reg);
+}
+
+static int ep93xx_i2s_enable(struct ep93xx_i2s_info *info, int stream)
+{
+	unsigned base_reg;
+	int err;
+
+	if ((ep93xx_i2s_read_reg(info, EP93XX_I2S_TX0EN) & 0x1) == 0 &&
+	    (ep93xx_i2s_read_reg(info, EP93XX_I2S_RX0EN) & 0x1) == 0) {
+		/* Enable clocks */
+		err = clk_prepare_enable(info->mclk);
+		if (err)
+			return err;
+		err = clk_prepare_enable(info->sclk);
+		if (err) {
+			clk_disable_unprepare(info->mclk);
+			return err;
+		}
+		err = clk_prepare_enable(info->lrclk);
+		if (err) {
+			clk_disable_unprepare(info->sclk);
+			clk_disable_unprepare(info->mclk);
+			return err;
+		}
+
+		/* Enable i2s */
+		ep93xx_i2s_write_reg(info, EP93XX_I2S_GLCTRL, 1);
+	}
+
+	/* Enable fifo */
+	if (stream == SNDRV_PCM_STREAM_PLAYBACK)
+		base_reg = EP93XX_I2S_TX0EN;
+	else
+		base_reg = EP93XX_I2S_RX0EN;
+	ep93xx_i2s_write_reg(info, base_reg, 1);
+
+	/* Enable TX IRQs (FIFO empty or underflow) */
+	if (IS_ENABLED(CONFIG_SND_EP93XX_SOC_I2S_WATCHDOG) &&
+	    stream == SNDRV_PCM_STREAM_PLAYBACK)
+		ep93xx_i2s_write_reg(info, EP93XX_I2S_TXCTRL,
+				     EP93XX_I2S_TXCTRL_TXEMPTY_LVL |
+				     EP93XX_I2S_TXCTRL_TXUFIE);
+
+	return 0;
+}
+
+static void ep93xx_i2s_disable(struct ep93xx_i2s_info *info, int stream)
+{
+	unsigned base_reg;
+
+	/* Disable IRQs */
+	if (IS_ENABLED(CONFIG_SND_EP93XX_SOC_I2S_WATCHDOG) &&
+	    stream == SNDRV_PCM_STREAM_PLAYBACK)
+		ep93xx_i2s_write_reg(info, EP93XX_I2S_TXCTRL, 0);
+
+	/* Disable fifo */
+	if (stream == SNDRV_PCM_STREAM_PLAYBACK)
+		base_reg = EP93XX_I2S_TX0EN;
+	else
+		base_reg = EP93XX_I2S_RX0EN;
+	ep93xx_i2s_write_reg(info, base_reg, 0);
+
+	if ((ep93xx_i2s_read_reg(info, EP93XX_I2S_TX0EN) & 0x1) == 0 &&
+	    (ep93xx_i2s_read_reg(info, EP93XX_I2S_RX0EN) & 0x1) == 0) {
+		/* Disable i2s */
+		ep93xx_i2s_write_reg(info, EP93XX_I2S_GLCTRL, 0);
+
+		/* Disable clocks */
+		clk_disable_unprepare(info->lrclk);
+		clk_disable_unprepare(info->sclk);
+		clk_disable_unprepare(info->mclk);
+	}
+}
+
+/*
+ * According to documentation I2S controller can handle underflow conditions
+ * just fine, but in reality the state machine is sometimes confused so that
+ * the whole stream is shifted by one byte. The watchdog below disables the TX
+ * FIFO, fills the buffer with zeroes and re-enables the FIFO. State machine
+ * is being reset and by filling the buffer we get some time before next
+ * underflow happens.
+ */
+static irqreturn_t ep93xx_i2s_interrupt(int irq, void *dev_id)
+{
+	struct ep93xx_i2s_info *info = dev_id;
+
+	/* Disable FIFO */
+	ep93xx_i2s_write_reg(info, EP93XX_I2S_TX0EN, 0);
+	/*
+	 * Fill TX FIFO with zeroes, this way we can defer next IRQs as much as
+	 * possible and get more time for DMA to catch up. Actually there are
+	 * only 8 samples in this FIFO, so even on 8kHz maximum deferral here is
+	 * 1ms.
+	 */
+	while (!(ep93xx_i2s_read_reg(info, EP93XX_I2S_GLSTS) &
+		 EP93XX_I2S_GLSTS_TX0_FIFO_FULL)) {
+		ep93xx_i2s_write_reg(info, EP93XX_I2S_I2STX0LFT, 0);
+		ep93xx_i2s_write_reg(info, EP93XX_I2S_I2STX0RT, 0);
+	}
+	/* Re-enable FIFO */
+	ep93xx_i2s_write_reg(info, EP93XX_I2S_TX0EN, 1);
+
+	return IRQ_HANDLED;
+}
+
+static int ep93xx_i2s_dai_probe(struct snd_soc_dai *dai)
+{
+	struct ep93xx_i2s_info *info = snd_soc_dai_get_drvdata(dai);
+
+	snd_soc_dai_init_dma_data(dai,	&info->dma_params_tx,
+					&info->dma_params_rx);
+
+	return 0;
+}
+
+static int ep93xx_i2s_startup(struct snd_pcm_substream *substream,
+			      struct snd_soc_dai *dai)
+{
+	struct ep93xx_i2s_info *info = snd_soc_dai_get_drvdata(dai);
+
+	return ep93xx_i2s_enable(info, substream->stream);
+}
+
+static void ep93xx_i2s_shutdown(struct snd_pcm_substream *substream,
+				struct snd_soc_dai *dai)
+{
+	struct ep93xx_i2s_info *info = snd_soc_dai_get_drvdata(dai);
+
+	ep93xx_i2s_disable(info, substream->stream);
+}
+
+static int ep93xx_i2s_set_dai_fmt(struct snd_soc_dai *cpu_dai,
+				  unsigned int fmt)
+{
+	struct ep93xx_i2s_info *info = snd_soc_dai_get_drvdata(cpu_dai);
+	unsigned int clk_cfg;
+	unsigned int txlin_ctrl = 0;
+	unsigned int rxlin_ctrl = 0;
+
+	clk_cfg  = ep93xx_i2s_read_reg(info, EP93XX_I2S_RXCLKCFG);
+
+	switch (fmt & SND_SOC_DAIFMT_FORMAT_MASK) {
+	case SND_SOC_DAIFMT_I2S:
+		clk_cfg |= EP93XX_I2S_CLKCFG_REL;
+		break;
+
+	case SND_SOC_DAIFMT_LEFT_J:
+		clk_cfg &= ~EP93XX_I2S_CLKCFG_REL;
+		break;
+
+	case SND_SOC_DAIFMT_RIGHT_J:
+		clk_cfg &= ~EP93XX_I2S_CLKCFG_REL;
+		rxlin_ctrl |= EP93XX_I2S_RXLINCTRLDATA_R_JUST;
+		txlin_ctrl |= EP93XX_I2S_TXLINCTRLDATA_R_JUST;
+		break;
+
+	default:
+		return -EINVAL;
+	}
+
+	switch (fmt & SND_SOC_DAIFMT_CLOCK_PROVIDER_MASK) {
+	case SND_SOC_DAIFMT_BP_FP:
+		/* CPU is provider */
+		clk_cfg |= EP93XX_I2S_CLKCFG_MASTER;
+		break;
+
+	case SND_SOC_DAIFMT_BC_FC:
+		/* Codec is provider */
+		clk_cfg &= ~EP93XX_I2S_CLKCFG_MASTER;
+		break;
+
+	default:
+		return -EINVAL;
+	}
+
+	switch (fmt & SND_SOC_DAIFMT_INV_MASK) {
+	case SND_SOC_DAIFMT_NB_NF:
+		/* Negative bit clock, lrclk low on left word */
+		clk_cfg &= ~(EP93XX_I2S_CLKCFG_CKP | EP93XX_I2S_CLKCFG_LRS);
+		break;
+
+	case SND_SOC_DAIFMT_NB_IF:
+		/* Negative bit clock, lrclk low on right word */
+		clk_cfg &= ~EP93XX_I2S_CLKCFG_CKP;
+		clk_cfg |= EP93XX_I2S_CLKCFG_LRS;
+		break;
+
+	case SND_SOC_DAIFMT_IB_NF:
+		/* Positive bit clock, lrclk low on left word */
+		clk_cfg |= EP93XX_I2S_CLKCFG_CKP;
+		clk_cfg &= ~EP93XX_I2S_CLKCFG_LRS;
+		break;
+
+	case SND_SOC_DAIFMT_IB_IF:
+		/* Positive bit clock, lrclk low on right word */
+		clk_cfg |= EP93XX_I2S_CLKCFG_CKP | EP93XX_I2S_CLKCFG_LRS;
+		break;
+	}
+
+	/* Write new register values */
+	ep93xx_i2s_write_reg(info, EP93XX_I2S_RXCLKCFG, clk_cfg);
+	ep93xx_i2s_write_reg(info, EP93XX_I2S_TXCLKCFG, clk_cfg);
+	ep93xx_i2s_write_reg(info, EP93XX_I2S_RXLINCTRLDATA, rxlin_ctrl);
+	ep93xx_i2s_write_reg(info, EP93XX_I2S_TXLINCTRLDATA, txlin_ctrl);
+	return 0;
+}
+
+static int ep93xx_i2s_hw_params(struct snd_pcm_substream *substream,
+				struct snd_pcm_hw_params *params,
+				struct snd_soc_dai *dai)
+{
+	struct ep93xx_i2s_info *info = snd_soc_dai_get_drvdata(dai);
+	unsigned word_len, div, sdiv, lrdiv;
+	int err;
+
+	switch (params_format(params)) {
+	case SNDRV_PCM_FORMAT_S16_LE:
+		word_len = EP93XX_I2S_WRDLEN_16;
+		break;
+
+	case SNDRV_PCM_FORMAT_S24_LE:
+		word_len = EP93XX_I2S_WRDLEN_24;
+		break;
+
+	case SNDRV_PCM_FORMAT_S32_LE:
+		word_len = EP93XX_I2S_WRDLEN_32;
+		break;
+
+	default:
+		return -EINVAL;
+	}
+
+	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
+		ep93xx_i2s_write_reg(info, EP93XX_I2S_TXWRDLEN, word_len);
+	else
+		ep93xx_i2s_write_reg(info, EP93XX_I2S_RXWRDLEN, word_len);
+
+	/*
+	 * EP93xx I2S module can be setup so SCLK / LRCLK value can be
+	 * 32, 64, 128. MCLK / SCLK value can be 2 and 4.
+	 * We set LRCLK equal to `rate' and minimum SCLK / LRCLK 
+	 * value is 64, because our sample size is 32 bit * 2 channels.
+	 * I2S standard permits us to transmit more bits than
+	 * the codec uses.
+	 */
+	div = clk_get_rate(info->mclk) / params_rate(params);
+	sdiv = 4;
+	if (div > (256 + 512) / 2) {
+		lrdiv = 128;
+	} else {
+		lrdiv = 64;
+		if (div < (128 + 256) / 2)
+			sdiv = 2;
+	}
+
+	err = clk_set_rate(info->sclk, clk_get_rate(info->mclk) / sdiv);
+	if (err)
+		return err;
+
+	err = clk_set_rate(info->lrclk, clk_get_rate(info->sclk) / lrdiv);
+	if (err)
+		return err;
+
+	return 0;
+}
+
+static int ep93xx_i2s_set_sysclk(struct snd_soc_dai *cpu_dai, int clk_id,
+				 unsigned int freq, int dir)
+{
+	struct ep93xx_i2s_info *info = snd_soc_dai_get_drvdata(cpu_dai);
+
+	if (dir == SND_SOC_CLOCK_IN || clk_id != 0)
+		return -EINVAL;
+	if (!freq)
+		return 0;
+
+	return clk_set_rate(info->mclk, freq);
+}
+
+#ifdef CONFIG_PM
+static int ep93xx_i2s_suspend(struct snd_soc_component *component)
+{
+	struct ep93xx_i2s_info *info = snd_soc_component_get_drvdata(component);
+
+	if (!snd_soc_component_active(component))
+		return 0;
+
+	ep93xx_i2s_disable(info, SNDRV_PCM_STREAM_PLAYBACK);
+	ep93xx_i2s_disable(info, SNDRV_PCM_STREAM_CAPTURE);
+
+	return 0;
+}
+
+static int ep93xx_i2s_resume(struct snd_soc_component *component)
+{
+	struct ep93xx_i2s_info *info = snd_soc_component_get_drvdata(component);
+	int err;
+
+	if (!snd_soc_component_active(component))
+		return 0;
+
+	err = ep93xx_i2s_enable(info, SNDRV_PCM_STREAM_PLAYBACK);
+	if (err)
+		return err;
+
+	return ep93xx_i2s_enable(info, SNDRV_PCM_STREAM_CAPTURE);
+}
+#else
+#define ep93xx_i2s_suspend	NULL
+#define ep93xx_i2s_resume	NULL
+#endif
+
+static const struct snd_soc_dai_ops ep93xx_i2s_dai_ops = {
+	.probe		= ep93xx_i2s_dai_probe,
+	.startup	= ep93xx_i2s_startup,
+	.shutdown	= ep93xx_i2s_shutdown,
+	.hw_params	= ep93xx_i2s_hw_params,
+	.set_sysclk	= ep93xx_i2s_set_sysclk,
+	.set_fmt	= ep93xx_i2s_set_dai_fmt,
+};
+
+#define EP93XX_I2S_FORMATS (SNDRV_PCM_FMTBIT_S32_LE)
+
+static struct snd_soc_dai_driver ep93xx_i2s_dai = {
+	.symmetric_rate	= 1,
+	.playback	= {
+		.channels_min	= 2,
+		.channels_max	= 2,
+		.rates		= SNDRV_PCM_RATE_8000_192000,
+		.formats	= EP93XX_I2S_FORMATS,
+	},
+	.capture	= {
+		 .channels_min	= 2,
+		 .channels_max	= 2,
+		 .rates		= SNDRV_PCM_RATE_8000_192000,
+		 .formats	= EP93XX_I2S_FORMATS,
+	},
+	.ops		= &ep93xx_i2s_dai_ops,
+};
+
+static const struct snd_soc_component_driver ep93xx_i2s_component = {
+	.name			= "ep93xx-i2s",
+	.suspend		= ep93xx_i2s_suspend,
+	.resume			= ep93xx_i2s_resume,
+	.legacy_dai_naming	= 1,
+};
+
+static int ep93xx_i2s_probe(struct platform_device *pdev)
+{
+	struct ep93xx_i2s_info *info;
+	int err;
+
+	info = devm_kzalloc(&pdev->dev, sizeof(*info), GFP_KERNEL);
+	if (!info)
+		return -ENOMEM;
+
+	info->regs = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(info->regs))
+		return PTR_ERR(info->regs);
+
+	if (IS_ENABLED(CONFIG_SND_EP93XX_SOC_I2S_WATCHDOG)) {
+		int irq = platform_get_irq(pdev, 0);
+		if (irq <= 0)
+			return irq < 0 ? irq : -ENODEV;
+
+		err = devm_request_irq(&pdev->dev, irq, ep93xx_i2s_interrupt, 0,
+				       pdev->name, info);
+		if (err)
+			return err;
+	}
+
+	info->mclk = clk_get(&pdev->dev, "mclk");
+	if (IS_ERR(info->mclk)) {
+		err = PTR_ERR(info->mclk);
+		goto fail;
+	}
+
+	info->sclk = clk_get(&pdev->dev, "sclk");
+	if (IS_ERR(info->sclk)) {
+		err = PTR_ERR(info->sclk);
+		goto fail_put_mclk;
+	}
+
+	info->lrclk = clk_get(&pdev->dev, "lrclk");
+	if (IS_ERR(info->lrclk)) {
+		err = PTR_ERR(info->lrclk);
+		goto fail_put_sclk;
+	}
+
+	dev_set_drvdata(&pdev->dev, info);
+
+	err = devm_snd_soc_register_component(&pdev->dev, &ep93xx_i2s_component,
+					 &ep93xx_i2s_dai, 1);
+	if (err)
+		goto fail_put_lrclk;
+
+	err = devm_ep93xx_pcm_platform_register(&pdev->dev);
+	if (err)
+		goto fail_put_lrclk;
+
+	return 0;
+
+fail_put_lrclk:
+	clk_put(info->lrclk);
+fail_put_sclk:
+	clk_put(info->sclk);
+fail_put_mclk:
+	clk_put(info->mclk);
+fail:
+	return err;
+}
+
+static void ep93xx_i2s_remove(struct platform_device *pdev)
+{
+	struct ep93xx_i2s_info *info = dev_get_drvdata(&pdev->dev);
+
+	clk_put(info->lrclk);
+	clk_put(info->sclk);
+	clk_put(info->mclk);
+}
+
+static const struct of_device_id ep93xx_i2s_of_ids[] = {
+	{ .compatible = "cirrus,ep9301-i2s" },
+	{}
+};
+MODULE_DEVICE_TABLE(of, ep93xx_i2s_of_ids);
+
+static struct platform_driver ep93xx_i2s_driver = {
+	.probe	= ep93xx_i2s_probe,
+	.remove = ep93xx_i2s_remove,
+	.driver	= {
+		.name	= "ep93xx-i2s",
+		.of_match_table = ep93xx_i2s_of_ids,
+	},
+};
+
+module_platform_driver(ep93xx_i2s_driver);
+
+MODULE_ALIAS("platform:ep93xx-i2s");
+MODULE_AUTHOR("Ryan Mallon");
+MODULE_DESCRIPTION("EP93XX I2S driver");
+MODULE_LICENSE("GPL");

linux-7.2.3/sound/soc/cirrus/ep93xx-pcm.c

@@ -0,0 +1,50 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * linux/sound/arm/ep93xx-pcm.c - EP93xx ALSA PCM interface
+ *
+ * Copyright (C) 2006 Lennert Buytenhek <buytenh@wantstofly.org>
+ * Copyright (C) 2006 Applied Data Systems
+ *
+ * Rewritten for the SoC audio subsystem (Based on PXA2xx code):
+ *   Copyright (c) 2008 Ryan Mallon
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/platform_device.h>
+#include <linux/dmaengine.h>
+
+#include <sound/pcm.h>
+#include <sound/soc.h>
+#include <sound/dmaengine_pcm.h>
+
+#include "ep93xx-pcm.h"
+
+static const struct snd_pcm_hardware ep93xx_pcm_hardware = {
+	.info			= (SNDRV_PCM_INFO_MMAP		|
+				   SNDRV_PCM_INFO_MMAP_VALID	|
+				   SNDRV_PCM_INFO_INTERLEAVED	|
+				   SNDRV_PCM_INFO_BLOCK_TRANSFER),
+	.buffer_bytes_max	= 131072,
+	.period_bytes_min	= 32,
+	.period_bytes_max	= 32768,
+	.periods_min		= 1,
+	.periods_max		= 32,
+	.fifo_size		= 32,
+};
+
+static const struct snd_dmaengine_pcm_config ep93xx_dmaengine_pcm_config = {
+	.pcm_hardware = &ep93xx_pcm_hardware,
+	.prealloc_buffer_size = 131072,
+};
+
+int devm_ep93xx_pcm_platform_register(struct device *dev)
+{
+	return devm_snd_dmaengine_pcm_register(dev,
+		&ep93xx_dmaengine_pcm_config, 0);
+}
+EXPORT_SYMBOL_GPL(devm_ep93xx_pcm_platform_register);
+
+MODULE_AUTHOR("Ryan Mallon");
+MODULE_DESCRIPTION("EP93xx ALSA PCM interface");
+MODULE_LICENSE("GPL");

linux-7.2.3/sound/soc/cirrus/ep93xx-pcm.h

@@ -0,0 +1,11 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (c) 2013, NVIDIA CORPORATION.  All rights reserved.
+ */
+
+#ifndef __EP93XX_PCM_H__
+#define __EP93XX_PCM_H__
+
+int devm_ep93xx_pcm_platform_register(struct device *dev);
+
+#endif