ASoC: Tegra: Implement SPDIF CPU DAI

This is a minimal driver for the Tegra SPDIF controller.

In hardware, the SPDIF output signal is always routed to any active HDMI
display controllers, and may also be routed to external pins on Tegra
using the pinmux.

Signed-off-by: Stephen Warren <swarren@nvidia.com>
Acked-by: Liam Girdwood <lrg@ti.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

1 files changed, 371 insertions, 0 deletions

diff --git a/sound/soc/tegra/tegra_spdif.c b/sound/soc/tegra/tegra_spdif.c
new file mode 100644
index 000000000000..abe606b0a29e
--- /dev/null
+++ b/sound/soc/tegra/tegra_spdif.c
@@ -0,0 +1,371 @@
+/*
+ * tegra_spdif.c - Tegra SPDIF driver
+ *
+ * Author: Stephen Warren <swarren@nvidia.com>
+ * Copyright (C) 2011 - NVIDIA, Inc.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
+ * 02110-1301 USA
+ *
+ */
+
+#include <linux/clk.h>
+#include <linux/module.h>
+#include <linux/debugfs.h>
+#include <linux/device.h>
+#include <linux/platform_device.h>
+#include <linux/seq_file.h>
+#include <linux/slab.h>
+#include <linux/io.h>
+#include <mach/iomap.h>
+#include <sound/core.h>
+#include <sound/pcm.h>
+#include <sound/pcm_params.h>
+#include <sound/soc.h>
+
+#include "tegra_spdif.h"
+
+#define DRV_NAME "tegra-spdif"
+
+static inline void tegra_spdif_write(struct tegra_spdif *spdif, u32 reg,
+					u32 val)
+{
+	__raw_writel(val, spdif->regs + reg);
+}
+
+static inline u32 tegra_spdif_read(struct tegra_spdif *spdif, u32 reg)
+{
+	return __raw_readl(spdif->regs + reg);
+}
+
+#ifdef CONFIG_DEBUG_FS
+static int tegra_spdif_show(struct seq_file *s, void *unused)
+{
+#define REG(r) { r, #r }
+	static const struct {
+		int offset;
+		const char *name;
+	} regs[] = {
+		REG(TEGRA_SPDIF_CTRL),
+		REG(TEGRA_SPDIF_STATUS),
+		REG(TEGRA_SPDIF_STROBE_CTRL),
+		REG(TEGRA_SPDIF_DATA_FIFO_CSR),
+		REG(TEGRA_SPDIF_CH_STA_RX_A),
+		REG(TEGRA_SPDIF_CH_STA_RX_B),
+		REG(TEGRA_SPDIF_CH_STA_RX_C),
+		REG(TEGRA_SPDIF_CH_STA_RX_D),
+		REG(TEGRA_SPDIF_CH_STA_RX_E),
+		REG(TEGRA_SPDIF_CH_STA_RX_F),
+		REG(TEGRA_SPDIF_CH_STA_TX_A),
+		REG(TEGRA_SPDIF_CH_STA_TX_B),
+		REG(TEGRA_SPDIF_CH_STA_TX_C),
+		REG(TEGRA_SPDIF_CH_STA_TX_D),
+		REG(TEGRA_SPDIF_CH_STA_TX_E),
+		REG(TEGRA_SPDIF_CH_STA_TX_F),
+	};
+#undef REG
+
+	struct tegra_spdif *spdif = s->private;
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(regs); i++) {
+		u32 val = tegra_spdif_read(spdif, regs[i].offset);
+		seq_printf(s, "%s = %08x\n", regs[i].name, val);
+	}
+
+	return 0;
+}
+
+static int tegra_spdif_debug_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, tegra_spdif_show, inode->i_private);
+}
+
+static const struct file_operations tegra_spdif_debug_fops = {
+	.open    = tegra_spdif_debug_open,
+	.read    = seq_read,
+	.llseek  = seq_lseek,
+	.release = single_release,
+};
+
+static void tegra_spdif_debug_add(struct tegra_spdif *spdif)
+{
+	spdif->debug = debugfs_create_file(DRV_NAME, S_IRUGO,
+						snd_soc_debugfs_root, spdif,
+						&tegra_spdif_debug_fops);
+}
+
+static void tegra_spdif_debug_remove(struct tegra_spdif *spdif)
+{
+	if (spdif->debug)
+		debugfs_remove(spdif->debug);
+}
+#else
+static inline void tegra_spdif_debug_add(struct tegra_spdif *spdif)
+{
+}
+
+static inline void tegra_spdif_debug_remove(struct tegra_spdif *spdif)
+{
+}
+#endif
+
+static int tegra_spdif_hw_params(struct snd_pcm_substream *substream,
+				struct snd_pcm_hw_params *params,
+				struct snd_soc_dai *dai)
+{
+	struct device *dev = substream->pcm->card->dev;
+	struct tegra_spdif *spdif = snd_soc_dai_get_drvdata(dai);
+	int ret, srate, spdifclock;
+
+	spdif->reg_ctrl &= ~TEGRA_SPDIF_CTRL_PACK;
+	spdif->reg_ctrl &= ~TEGRA_SPDIF_CTRL_BIT_MODE_MASK;
+	switch (params_format(params)) {
+	case SNDRV_PCM_FORMAT_S16_LE:
+		spdif->reg_ctrl |= TEGRA_SPDIF_CTRL_PACK;
+		spdif->reg_ctrl |= TEGRA_SPDIF_CTRL_BIT_MODE_16BIT;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	srate = params_rate(params);
+	switch (params_rate(params)) {
+	case 32000:
+		spdifclock = 4096000;
+		break;
+	case 44100:
+		spdifclock = 5644800;
+		break;
+	case 48000:
+		spdifclock = 6144000;
+		break;
+	case 88200:
+		spdifclock = 11289600;
+		break;
+	case 96000:
+		spdifclock = 12288000;
+		break;
+	case 176400:
+		spdifclock = 22579200;
+		break;
+	case 192000:
+		spdifclock = 24576000;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	ret = clk_set_rate(spdif->clk_spdif_out, spdifclock);
+	if (ret) {
+		dev_err(dev, "Can't set SPDIF clock rate: %d\n", ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+static void tegra_spdif_start_playback(struct tegra_spdif *spdif)
+{
+	spdif->reg_ctrl |= TEGRA_SPDIF_CTRL_TX_EN;
+	tegra_spdif_write(spdif, TEGRA_SPDIF_CTRL, spdif->reg_ctrl);
+}
+
+static void tegra_spdif_stop_playback(struct tegra_spdif *spdif)
+{
+	spdif->reg_ctrl &= ~TEGRA_SPDIF_CTRL_TX_EN;
+	tegra_spdif_write(spdif, TEGRA_SPDIF_CTRL, spdif->reg_ctrl);
+}
+
+static int tegra_spdif_trigger(struct snd_pcm_substream *substream, int cmd,
+				struct snd_soc_dai *dai)
+{
+	struct tegra_spdif *spdif = snd_soc_dai_get_drvdata(dai);
+
+	switch (cmd) {
+	case SNDRV_PCM_TRIGGER_START:
+	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
+	case SNDRV_PCM_TRIGGER_RESUME:
+		if (!spdif->clk_refs)
+			clk_enable(spdif->clk_spdif_out);
+		spdif->clk_refs++;
+		tegra_spdif_start_playback(spdif);
+		break;
+	case SNDRV_PCM_TRIGGER_STOP:
+	case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
+	case SNDRV_PCM_TRIGGER_SUSPEND:
+		tegra_spdif_stop_playback(spdif);
+		spdif->clk_refs--;
+		if (!spdif->clk_refs)
+			clk_disable(spdif->clk_spdif_out);
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int tegra_spdif_probe(struct snd_soc_dai *dai)
+{
+	struct tegra_spdif *spdif = snd_soc_dai_get_drvdata(dai);
+
+	dai->capture_dma_data = NULL;
+	dai->playback_dma_data = &spdif->playback_dma_data;
+
+	return 0;
+}
+
+static struct snd_soc_dai_ops tegra_spdif_dai_ops = {
+	.hw_params	= tegra_spdif_hw_params,
+	.trigger	= tegra_spdif_trigger,
+};
+
+struct snd_soc_dai_driver tegra_spdif_dai = {
+	.name = DRV_NAME,
+	.probe = tegra_spdif_probe,
+	.playback = {
+		.channels_min = 2,
+		.channels_max = 2,
+		.rates = SNDRV_PCM_RATE_32000 | SNDRV_PCM_RATE_44100 |
+				SNDRV_PCM_RATE_48000,
+		.formats = SNDRV_PCM_FMTBIT_S16_LE,
+	},
+	.ops = &tegra_spdif_dai_ops,
+};
+
+static __devinit int tegra_spdif_platform_probe(struct platform_device *pdev)
+{
+	struct tegra_spdif *spdif;
+	struct resource *mem, *memregion, *dmareq;
+	int ret;
+
+	spdif = kzalloc(sizeof(struct tegra_spdif), GFP_KERNEL);
+	if (!spdif) {
+		dev_err(&pdev->dev, "Can't allocate tegra_spdif\n");
+		ret = -ENOMEM;
+		goto exit;
+	}
+	dev_set_drvdata(&pdev->dev, spdif);
+
+	spdif->clk_spdif_out = clk_get(&pdev->dev, "spdif_out");
+	if (IS_ERR(spdif->clk_spdif_out)) {
+		pr_err("Can't retrieve spdif clock\n");
+		ret = PTR_ERR(spdif->clk_spdif_out);
+		goto err_free;
+	}
+
+	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!mem) {
+		dev_err(&pdev->dev, "No memory resource\n");
+		ret = -ENODEV;
+		goto err_clk_put;
+	}
+
+	dmareq = platform_get_resource(pdev, IORESOURCE_DMA, 0);
+	if (!dmareq) {
+		dev_err(&pdev->dev, "No DMA resource\n");
+		ret = -ENODEV;
+		goto err_clk_put;
+	}
+
+	memregion = request_mem_region(mem->start, resource_size(mem),
+					DRV_NAME);
+	if (!memregion) {
+		dev_err(&pdev->dev, "Memory region already claimed\n");
+		ret = -EBUSY;
+		goto err_clk_put;
+	}
+
+	spdif->regs = ioremap(mem->start, resource_size(mem));
+	if (!spdif->regs) {
+		dev_err(&pdev->dev, "ioremap failed\n");
+		ret = -ENOMEM;
+		goto err_release;
+	}
+
+	spdif->playback_dma_data.addr = mem->start + TEGRA_SPDIF_DATA_OUT;
+	spdif->playback_dma_data.wrap = 4;
+	spdif->playback_dma_data.width = 32;
+	spdif->playback_dma_data.req_sel = dmareq->start;
+
+	ret = snd_soc_register_dai(&pdev->dev, &tegra_spdif_dai);
+	if (ret) {
+		dev_err(&pdev->dev, "Could not register DAI: %d\n", ret);
+		ret = -ENOMEM;
+		goto err_unmap;
+	}
+
+	tegra_spdif_debug_add(spdif);
+
+	return 0;
+
+err_unmap:
+	iounmap(spdif->regs);
+err_release:
+	release_mem_region(mem->start, resource_size(mem));
+err_clk_put:
+	clk_put(spdif->clk_spdif_out);
+err_free:
+	kfree(spdif);
+exit:
+	return ret;
+}
+
+static int __devexit tegra_spdif_platform_remove(struct platform_device *pdev)
+{
+	struct tegra_spdif *spdif = dev_get_drvdata(&pdev->dev);
+	struct resource *res;
+
+	snd_soc_unregister_dai(&pdev->dev);
+
+	tegra_spdif_debug_remove(spdif);
+
+	iounmap(spdif->regs);
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	release_mem_region(res->start, resource_size(res));
+
+	clk_put(spdif->clk_spdif_out);
+
+	kfree(spdif);
+
+	return 0;
+}
+
+static struct platform_driver tegra_spdif_driver = {
+	.driver = {
+		.name = DRV_NAME,
+		.owner = THIS_MODULE,
+	},
+	.probe = tegra_spdif_platform_probe,
+	.remove = __devexit_p(tegra_spdif_platform_remove),
+};
+
+static int __init snd_tegra_spdif_init(void)
+{
+	return platform_driver_register(&tegra_spdif_driver);
+}
+module_init(snd_tegra_spdif_init);
+
+static void __exit snd_tegra_spdif_exit(void)
+{
+	platform_driver_unregister(&tegra_spdif_driver);
+}
+module_exit(snd_tegra_spdif_exit);
+
+MODULE_AUTHOR("Stephen Warren <swarren@nvidia.com>");
+MODULE_DESCRIPTION("Tegra SPDIF ASoC driver");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:" DRV_NAME);