Date:   Thu, 3 Jan 2019 23:39:52 +0530
From:   Maruthi Srinivas Bayyavarapu 
        <maruthi.srinivas.bayyavarapu@...inx.com>
To:     Liam Girdwood <lgirdwood@...il.com>,
        Mark Brown <broonie@...nel.org>,
        Jaroslav Kysela <perex@...ex.cz>,
        Takashi Iwai <tiwai@...e.com>,
        Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Vishal Sagar <vsagar@...inx.com>,
        Michal Simek <michal.simek@...inx.com>,
        Maruthi Srinivas Bayyavarapu 
        <maruthi.srinivas.bayyavarapu@...inx.com>,
        <devicetree@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <alsa-devel@...a-project.org>,
        <linux-arm-kernel@...ts.infradead.org>
Subject: [PATCH 2/3] ASoC: xlnx: add SPDIF audio driver

Added SPDIF audio driver. This provides playback and capture of
AES audio over SPDIF interface.

Signed-off-by: Maruthi Srinivas Bayyavarapu <maruthi.srinivas.bayyavarapu@...inx.com>
---
 sound/soc/xilinx/xlnx_spdif.c | 339 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 339 insertions(+)
 create mode 100644 sound/soc/xilinx/xlnx_spdif.c

diff --git a/sound/soc/xilinx/xlnx_spdif.c b/sound/soc/xilinx/xlnx_spdif.c
new file mode 100644
index 0000000..3b9000f
--- /dev/null
+++ b/sound/soc/xilinx/xlnx_spdif.c
@@ -0,0 +1,339 @@
+// SPDX-License-Identifier: GPL-2.0
+//
+// Xilinx ASoC SPDIF audio support
+//
+// Copyright (C) 2018 Xilinx, Inc.
+//
+// Author: Maruthi Srinivas Bayyavarapu <maruthis@...inx.com>
+//
+
+#include <linux/clk.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_platform.h>
+#include <linux/platform_device.h>
+#include <sound/pcm_params.h>
+#include <sound/soc.h>
+
+#define XLNX_SPDIF_RATES \
+	(SNDRV_PCM_RATE_32000 | SNDRV_PCM_RATE_44100 | SNDRV_PCM_RATE_48000 | \
+	SNDRV_PCM_RATE_88200 | SNDRV_PCM_RATE_96000 | SNDRV_PCM_RATE_176400 | \
+	SNDRV_PCM_RATE_192000)
+
+#define XLNX_SPDIF_FORMATS (SNDRV_PCM_FMTBIT_S16_LE | SNDRV_PCM_FMTBIT_S24_LE)
+
+#define XSPDIF_IRQ_STS_REG		0x20
+#define XSPDIF_IRQ_ENABLE_REG		0x28
+#define XSPDIF_SOFT_RESET_REG		0x40
+#define XSPDIF_CONTROL_REG		0x44
+#define XSPDIF_CHAN_0_STS_REG		0x4C
+#define XSPDIF_GLOBAL_IRQ_ENABLE_REG	0x1C
+#define XSPDIF_CH_A_USER_DATA_REG_0	0x64
+
+#define XSPDIF_CORE_ENABLE_MASK		BIT(0)
+#define XSPDIF_FIFO_FLUSH_MASK		BIT(1)
+#define XSPDIF_CH_STS_MASK		BIT(5)
+#define XSPDIF_GLOBAL_IRQ_ENABLE	BIT(31)
+#define XSPDIF_CLOCK_CONFIG_BITS_MASK	GENMASK(5, 2)
+#define XSPDIF_CLOCK_CONFIG_BITS_SHIFT	2
+#define XSPDIF_SOFT_RESET_VALUE		0xA
+
+#define MAX_CHANNELS			2
+#define AES_SAMPLE_WIDTH		32
+#define CH_STATUS_UPDATE_TIMEOUT	40
+
+struct spdif_dev_data {
+	u32 mode;
+	u32 aclk;
+	bool rx_chsts_updated;
+	void __iomem *base;
+	struct clk *axi_clk;
+	wait_queue_head_t chsts_q;
+};
+
+static irqreturn_t xlnx_spdifrx_irq_handler(int irq, void *arg)
+{
+	u32 val;
+	struct spdif_dev_data *ctx = arg;
+
+	val = readl(ctx->base + XSPDIF_IRQ_STS_REG);
+	if (val & XSPDIF_CH_STS_MASK) {
+		writel(val & XSPDIF_CH_STS_MASK,
+		       ctx->base + XSPDIF_IRQ_STS_REG);
+		val = readl(ctx->base +
+			    XSPDIF_IRQ_ENABLE_REG);
+		writel(val & ~XSPDIF_CH_STS_MASK,
+		       ctx->base + XSPDIF_IRQ_ENABLE_REG);
+
+		ctx->rx_chsts_updated = true;
+		wake_up_interruptible(&ctx->chsts_q);
+		return IRQ_HANDLED;
+	}
+
+	return IRQ_NONE;
+}
+
+static int xlnx_spdif_startup(struct snd_pcm_substream *substream,
+			      struct snd_soc_dai *dai)
+{
+	u32 val;
+	struct spdif_dev_data *ctx = dev_get_drvdata(dai->dev);
+
+	val = readl(ctx->base + XSPDIF_CONTROL_REG);
+	val |= XSPDIF_FIFO_FLUSH_MASK;
+	writel(val, ctx->base + XSPDIF_CONTROL_REG);
+
+	if (substream->stream == SNDRV_PCM_STREAM_CAPTURE) {
+		writel(XSPDIF_CH_STS_MASK,
+		       ctx->base + XSPDIF_IRQ_ENABLE_REG);
+		writel(XSPDIF_GLOBAL_IRQ_ENABLE,
+		       ctx->base + XSPDIF_GLOBAL_IRQ_ENABLE_REG);
+	}
+
+	return 0;
+}
+
+static void xlnx_spdif_shutdown(struct snd_pcm_substream *substream,
+				struct snd_soc_dai *dai)
+{
+	struct spdif_dev_data *ctx = dev_get_drvdata(dai->dev);
+
+	writel(XSPDIF_SOFT_RESET_VALUE, ctx->base + XSPDIF_SOFT_RESET_REG);
+}
+
+static int xlnx_spdif_hw_params(struct snd_pcm_substream *substream,
+				struct snd_pcm_hw_params *params,
+				struct snd_soc_dai *dai)
+{
+	u32 val, clk_div, clk_cfg;
+	struct spdif_dev_data *ctx = dev_get_drvdata(dai->dev);
+
+	clk_div = DIV_ROUND_CLOSEST(ctx->aclk, MAX_CHANNELS * AES_SAMPLE_WIDTH *
+				    params_rate(params));
+
+	switch (clk_div) {
+	case 4:
+		clk_cfg = 0;
+		break;
+	case 8:
+		clk_cfg = 1;
+		break;
+	case 16:
+		clk_cfg = 2;
+		break;
+	case 24:
+		clk_cfg = 3;
+		break;
+	case 32:
+		clk_cfg = 4;
+		break;
+	case 48:
+		clk_cfg = 5;
+		break;
+	case 64:
+		clk_cfg = 6;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	val = readl(ctx->base + XSPDIF_CONTROL_REG);
+	val &= ~XSPDIF_CLOCK_CONFIG_BITS_MASK;
+	val |= clk_cfg << XSPDIF_CLOCK_CONFIG_BITS_SHIFT;
+	writel(val, ctx->base + XSPDIF_CONTROL_REG);
+
+	return 0;
+}
+
+static int rx_stream_detect(struct snd_soc_dai *dai)
+{
+	int err;
+	struct spdif_dev_data *ctx = dev_get_drvdata(dai->dev);
+	unsigned long jiffies = msecs_to_jiffies(CH_STATUS_UPDATE_TIMEOUT);
+
+	/* start capture only if stream is detected within 40ms timeout */
+	err = wait_event_interruptible_timeout(ctx->chsts_q,
+					       ctx->rx_chsts_updated,
+					       jiffies);
+	if (!err) {
+		dev_err(dai->dev, "No streaming audio detected!\n");
+		return -EINVAL;
+	}
+	ctx->rx_chsts_updated = false;
+
+	return 0;
+}
+
+static int xlnx_spdif_trigger(struct snd_pcm_substream *substream, int cmd,
+			      struct snd_soc_dai *dai)
+{
+	u32 val;
+	int ret = 0;
+	struct spdif_dev_data *ctx = dev_get_drvdata(dai->dev);
+
+	val = readl(ctx->base + XSPDIF_CONTROL_REG);
+	switch (cmd) {
+	case SNDRV_PCM_TRIGGER_START:
+	case SNDRV_PCM_TRIGGER_RESUME:
+	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
+		val |= XSPDIF_CORE_ENABLE_MASK;
+		writel(val, ctx->base + XSPDIF_CONTROL_REG);
+		if (substream->stream == SNDRV_PCM_STREAM_CAPTURE)
+			ret = rx_stream_detect(dai);
+		break;
+	case SNDRV_PCM_TRIGGER_STOP:
+	case SNDRV_PCM_TRIGGER_SUSPEND:
+	case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
+		val &= ~XSPDIF_CORE_ENABLE_MASK;
+		writel(val, ctx->base + XSPDIF_CONTROL_REG);
+		break;
+	default:
+		ret = -EINVAL;
+	}
+
+	return ret;
+}
+
+static const struct snd_soc_dai_ops xlnx_spdif_dai_ops = {
+	.startup = xlnx_spdif_startup,
+	.shutdown = xlnx_spdif_shutdown,
+	.trigger = xlnx_spdif_trigger,
+	.hw_params = xlnx_spdif_hw_params,
+};
+
+static struct snd_soc_dai_driver xlnx_spdif_tx_dai = {
+	.name = "xlnx_spdif_tx",
+	.playback = {
+		.channels_min = 2,
+		.channels_max = 2,
+		.rates = XLNX_SPDIF_RATES,
+		.formats = XLNX_SPDIF_FORMATS,
+	},
+	.ops = &xlnx_spdif_dai_ops,
+};
+
+static struct snd_soc_dai_driver xlnx_spdif_rx_dai = {
+	.name = "xlnx_spdif_rx",
+	.capture = {
+		.channels_min = 2,
+		.channels_max = 2,
+		.rates = XLNX_SPDIF_RATES,
+		.formats = XLNX_SPDIF_FORMATS,
+	},
+	.ops = &xlnx_spdif_dai_ops,
+};
+
+static const struct snd_soc_component_driver xlnx_spdif_component = {
+	.name = "xlnx-spdif",
+};
+
+static const struct of_device_id xlnx_spdif_of_match[] = {
+	{ .compatible = "xlnx,spdif-2.0", },
+	{},
+};
+MODULE_DEVICE_TABLE(of, xlnx_spdif_of_match);
+
+static int xlnx_spdif_probe(struct platform_device *pdev)
+{
+	int ret;
+	struct resource *res;
+	struct snd_soc_dai_driver *dai_drv;
+	struct spdif_dev_data *ctx;
+
+	struct device *dev = &pdev->dev;
+	struct device_node *node = dev->of_node;
+
+	ctx = devm_kzalloc(dev, sizeof(*ctx), GFP_KERNEL);
+	if (!ctx)
+		return -ENOMEM;
+
+	ctx->axi_clk = devm_clk_get(dev, "s_axi_aclk");
+	if (IS_ERR(ctx->axi_clk)) {
+		ret = PTR_ERR(ctx->axi_clk);
+		dev_err(dev, "failed to get s_axi_aclk(%d)\n", ret);
+		return ret;
+	}
+	ret = clk_prepare_enable(ctx->axi_clk);
+	if (ret) {
+		dev_err(dev, "failed to enable s_axi_aclk(%d)\n", ret);
+		return ret;
+	}
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	ctx->base = devm_ioremap_resource(dev, res);
+	if (IS_ERR(ctx->base)) {
+		ret = PTR_ERR(ctx->base);
+		goto clk_err;
+	}
+	ret = of_property_read_u32(node, "xlnx,spdif-mode", &ctx->mode);
+	if (ret < 0) {
+		dev_err(dev, "cannot get SPDIF mode\n");
+		goto clk_err;
+	}
+	if (ctx->mode) {
+		dai_drv = &xlnx_spdif_tx_dai;
+	} else {
+		res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
+		if (!res) {
+			dev_err(dev, "No IRQ resource found\n");
+			ret = -ENODEV;
+			goto clk_err;
+		}
+		ret = devm_request_irq(dev, res->start,
+				       xlnx_spdifrx_irq_handler,
+				       0, "XLNX_SPDIF_RX", ctx);
+		if (ret) {
+			dev_err(dev, "spdif rx irq request failed\n");
+			ret = -ENODEV;
+			goto clk_err;
+		}
+
+		init_waitqueue_head(&ctx->chsts_q);
+		dai_drv = &xlnx_spdif_rx_dai;
+	}
+
+	ret = of_property_read_u32(node, "xlnx,aud_clk_i", &ctx->aclk);
+	if (ret < 0) {
+		dev_err(dev, "cannot get aud_clk_i value\n");
+		goto clk_err;
+	}
+
+	dev_set_drvdata(dev, ctx);
+
+	ret = devm_snd_soc_register_component(dev, &xlnx_spdif_component,
+					      dai_drv, 1);
+	if (ret) {
+		dev_err(dev, "SPDIF component registration failed\n");
+		goto clk_err;
+	}
+
+	writel(XSPDIF_SOFT_RESET_VALUE, ctx->base + XSPDIF_SOFT_RESET_REG);
+	dev_info(dev, "%s DAI registered\n", dai_drv->name);
+
+clk_err:
+	clk_disable_unprepare(ctx->axi_clk);
+	return ret;
+}
+
+static int xlnx_spdif_remove(struct platform_device *pdev)
+{
+	struct spdif_dev_data *ctx = dev_get_drvdata(&pdev->dev);
+
+	clk_disable_unprepare(ctx->axi_clk);
+	return 0;
+}
+
+static struct platform_driver xlnx_spdif_driver = {
+	.driver = {
+		.name = "xlnx-spdif",
+		.of_match_table = xlnx_spdif_of_match,
+	},
+	.probe = xlnx_spdif_probe,
+	.remove = xlnx_spdif_remove,
+};
+module_platform_driver(xlnx_spdif_driver);
+
+MODULE_AUTHOR("Maruthi Srinivas Bayyavarapu <maruthis@...inx.com>");
+MODULE_DESCRIPTION("XILINX SPDIF driver");
+MODULE_LICENSE("GPL v2");
-- 
2.7.4

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