ASoC: xlnx: Add i2s driver

I2S IP instance can work in transmitter/playback or receiver/capture mode
exclusively. The patch registers corresponding instance as ASoC component
with audio framework.
Signed-off-by: Maruthi Srinivas Bayyavarapu <maruthi.srinivas.bayyavarapu@xilinx.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

sound/soc/xilinx/xlnx_i2s.c

+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Xilinx ASoC I2S audio support
+ *
+ * Copyright (C) 2018 Xilinx, Inc.
+ *
+ * Author: Praveen Vuppala <praveenv@xilinx.com>
+ * Author: Maruthi Srinivas Bayyavarapu <maruthis@xilinx.com>
+ */
+
+#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 DRV_NAME "xlnx_i2s"
+
+#define I2S_CORE_CTRL_OFFSET		0x08
+#define I2S_I2STIM_OFFSET		0x20
+#define I2S_CH0_OFFSET			0x30
+#define I2S_I2STIM_VALID_MASK		GENMASK(7, 0)
+
+static int xlnx_i2s_set_sclkout_div(struct snd_soc_dai *cpu_dai,
+				    int div_id, int div)
+{
+	void __iomem *base = snd_soc_dai_get_drvdata(cpu_dai);
+
+	if (!div || (div & ~I2S_I2STIM_VALID_MASK))
+		return -EINVAL;
+
+	writel(div, base + I2S_I2STIM_OFFSET);
+
+	return 0;
+}
+
+static int xlnx_i2s_hw_params(struct snd_pcm_substream *substream,
+			      struct snd_pcm_hw_params *params,
+			      struct snd_soc_dai *i2s_dai)
+{
+	u32 reg_off, chan_id;
+	void __iomem *base = snd_soc_dai_get_drvdata(i2s_dai);
+
+	chan_id = params_channels(params) / 2;
+
+	while (chan_id > 0) {
+		reg_off = I2S_CH0_OFFSET + ((chan_id - 1) * 4);
+		writel(chan_id, base + reg_off);
+		chan_id--;
+	}
+
+	return 0;
+}
+
+static int xlnx_i2s_trigger(struct snd_pcm_substream *substream, int cmd,
+			    struct snd_soc_dai *i2s_dai)
+{
+	void __iomem *base = snd_soc_dai_get_drvdata(i2s_dai);
+
+	switch (cmd) {
+	case SNDRV_PCM_TRIGGER_START:
+	case SNDRV_PCM_TRIGGER_RESUME:
+	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
+		writel(1, base + I2S_CORE_CTRL_OFFSET);
+		break;
+	case SNDRV_PCM_TRIGGER_STOP:
+	case SNDRV_PCM_TRIGGER_SUSPEND:
+	case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
+		writel(0, base + I2S_CORE_CTRL_OFFSET);
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static const struct snd_soc_dai_ops xlnx_i2s_dai_ops = {
+	.trigger = xlnx_i2s_trigger,
+	.set_clkdiv = xlnx_i2s_set_sclkout_div,
+	.hw_params = xlnx_i2s_hw_params
+};
+
+static const struct snd_soc_component_driver xlnx_i2s_component = {
+	.name = DRV_NAME,
+};
+
+static const struct of_device_id xlnx_i2s_of_match[] = {
+	{ .compatible = "xlnx,i2s-transmitter-1.0", },
+	{ .compatible = "xlnx,i2s-receiver-1.0", },
+	{},
+};
+MODULE_DEVICE_TABLE(of, xlnx_i2s_of_match);
+
+static int xlnx_i2s_probe(struct platform_device *pdev)
+{
+	struct resource *res;
+	void __iomem *base;
+	struct snd_soc_dai_driver *dai_drv;
+	int ret;
+	u32 ch, format, data_width;
+	struct device *dev = &pdev->dev;
+	struct device_node *node = dev->of_node;
+
+	dai_drv = devm_kzalloc(&pdev->dev, sizeof(*dai_drv), GFP_KERNEL);
+	if (!dai_drv)
+		return -ENOMEM;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	base = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(base))
+		return PTR_ERR(base);
+
+	ret = of_property_read_u32(node, "xlnx,num-channels", &ch);
+	if (ret < 0) {
+		dev_err(dev, "cannot get supported channels\n");
+		return ret;
+	}
+	ch = ch * 2;
+
+	ret = of_property_read_u32(node, "xlnx,dwidth", &data_width);
+	if (ret < 0) {
+		dev_err(dev, "cannot get data width\n");
+		return ret;
+	}
+	switch (data_width) {
+	case 16:
+		format = SNDRV_PCM_FMTBIT_S16_LE;
+		break;
+	case 24:
+		format = SNDRV_PCM_FMTBIT_S24_LE;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	if (of_device_is_compatible(node, "xlnx,i2s-transmitter-1.0")) {
+		dai_drv->name = "xlnx_i2s_playback";
+		dai_drv->playback.stream_name = "Playback";
+		dai_drv->playback.formats = format;
+		dai_drv->playback.channels_min = ch;
+		dai_drv->playback.channels_max = ch;
+		dai_drv->playback.rates	= SNDRV_PCM_RATE_8000_192000;
+		dai_drv->ops = &xlnx_i2s_dai_ops;
+	} else if (of_device_is_compatible(node, "xlnx,i2s-receiver-1.0")) {
+		dai_drv->name = "xlnx_i2s_capture";
+		dai_drv->capture.stream_name = "Capture";
+		dai_drv->capture.formats = format;
+		dai_drv->capture.channels_min = ch;
+		dai_drv->capture.channels_max = ch;
+		dai_drv->capture.rates = SNDRV_PCM_RATE_8000_192000;
+		dai_drv->ops = &xlnx_i2s_dai_ops;
+	} else {
+		return -ENODEV;
+	}
+
+	dev_set_drvdata(&pdev->dev, base);
+
+	ret = devm_snd_soc_register_component(&pdev->dev, &xlnx_i2s_component,
+					      dai_drv, 1);
+	if (ret) {
+		dev_err(&pdev->dev, "i2s component registration failed\n");
+		return ret;
+	}
+
+	dev_info(&pdev->dev, "%s DAI registered\n", dai_drv->name);
+
+	return ret;
+}
+
+static struct platform_driver xlnx_i2s_aud_driver = {
+	.driver = {
+		.name = DRV_NAME,
+		.of_match_table = xlnx_i2s_of_match,
+	},
+	.probe = xlnx_i2s_probe,
+};
+
+module_platform_driver(xlnx_i2s_aud_driver);
+
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Praveen Vuppala  <praveenv@xilinx.com>");
+MODULE_AUTHOR("Maruthi Srinivas Bayyavarapu <maruthis@xilinx.com>");