ASoC: Add a driver for AK4104 S/PDIF transmitter

This adds a driver for the SPI connected AK4104 S/PDIF transmitter
device. Its features are fairly simple, but as there is need to set up
certain bits in the IEC958 information, this better goes into a real
driver.

Signed-off-by: Daniel Mack <daniel@caiaq.de>
Cc: Mark Brown <broonie@sirena.org.uk>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

1 files changed, 363 insertions, 0 deletions

diff --git a/sound/soc/codecs/ak4104.c b/sound/soc/codecs/ak4104.c
new file mode 100644
index 000000000000..338381f4fe1e
--- /dev/null
+++ b/sound/soc/codecs/ak4104.c
@@ -0,0 +1,363 @@
+/*
+ * AK4104 ALSA SoC (ASoC) driver
+ *
+ * Copyright (c) 2009 Daniel Mack <daniel@caiaq.de>
+ *
+ *  This program is free software; you can redistribute  it and/or modify it
+ *  under the terms of  the GNU General  Public License as published by the
+ *  Free Software Foundation;  either version 2 of the  License, or (at your
+ *  option) any later version.
+ */
+
+#include <linux/module.h>
+#include <sound/core.h>
+#include <sound/soc.h>
+#include <sound/initval.h>
+#include <linux/spi/spi.h>
+#include <sound/asoundef.h>
+
+#include "ak4104.h"
+
+/* AK4104 registers addresses */
+#define AK4104_REG_CONTROL1		0x00
+#define AK4104_REG_RESERVED		0x01
+#define AK4104_REG_CONTROL2		0x02
+#define AK4104_REG_TX			0x03
+#define AK4104_REG_CHN_STATUS(x)	((x) + 0x04)
+#define AK4104_NUM_REGS			10
+
+#define AK4104_REG_MASK			0x1f
+#define AK4104_READ			0xc0
+#define AK4104_WRITE			0xe0
+#define AK4104_RESERVED_VAL		0x5b
+
+/* Bit masks for AK4104 registers */
+#define AK4104_CONTROL1_RSTN		(1 << 0)
+#define AK4104_CONTROL1_PW		(1 << 1)
+#define AK4104_CONTROL1_DIF0		(1 << 2)
+#define AK4104_CONTROL1_DIF1		(1 << 3)
+
+#define AK4104_CONTROL2_SEL0		(1 << 0)
+#define AK4104_CONTROL2_SEL1		(1 << 1)
+#define AK4104_CONTROL2_MODE		(1 << 2)
+
+#define AK4104_TX_TXE			(1 << 0)
+#define AK4104_TX_V			(1 << 1)
+
+#define DRV_NAME "ak4104"
+
+struct ak4104_private {
+	struct snd_soc_codec codec;
+	u8 reg_cache[AK4104_NUM_REGS];
+};
+
+static int ak4104_fill_cache(struct snd_soc_codec *codec)
+{
+	int i;
+	u8 *reg_cache = codec->reg_cache;
+	struct spi_device *spi = codec->control_data;
+
+	for (i = 0; i < codec->reg_cache_size; i++) {
+		int ret = spi_w8r8(spi, i | AK4104_READ);
+		if (ret < 0) {
+			dev_err(&spi->dev, "SPI write failure\n");
+			return ret;
+		}
+
+		reg_cache[i] = ret;
+	}
+
+	return 0;
+}
+
+static unsigned int ak4104_read_reg_cache(struct snd_soc_codec *codec,
+					  unsigned int reg)
+{
+	u8 *reg_cache = codec->reg_cache;
+
+	if (reg >= codec->reg_cache_size)
+		return -EINVAL;
+
+	return reg_cache[reg];
+}
+
+static int ak4104_spi_write(struct snd_soc_codec *codec, unsigned int reg,
+			    unsigned int value)
+{
+	u8 *cache = codec->reg_cache;
+	struct spi_device *spi = codec->control_data;
+
+	if (reg >= codec->reg_cache_size)
+		return -EINVAL;
+
+	reg &= AK4104_REG_MASK;
+	reg |= AK4104_WRITE;
+
+	/* only write to the hardware if value has changed */
+	if (cache[reg] != value) {
+		u8 tmp[2] = { reg, value };
+		if (spi_write(spi, tmp, sizeof(tmp))) {
+			dev_err(&spi->dev, "SPI write failed\n");
+			return -EIO;
+		}
+
+		cache[reg] = value;
+	}
+
+	return 0;
+}
+
+static int ak4104_set_dai_fmt(struct snd_soc_dai *codec_dai,
+			      unsigned int format)
+{
+	struct snd_soc_codec *codec = codec_dai->codec;
+	int val = 0;
+
+	val = ak4104_read_reg_cache(codec, AK4104_REG_CONTROL1);
+	if (val < 0)
+		return val;
+
+	val &= ~(AK4104_CONTROL1_DIF0 | AK4104_CONTROL1_DIF1);
+
+	/* set DAI format */
+	switch (format & SND_SOC_DAIFMT_FORMAT_MASK) {
+	case SND_SOC_DAIFMT_RIGHT_J:
+		break;
+	case SND_SOC_DAIFMT_LEFT_J:
+		val |= AK4104_CONTROL1_DIF0;
+		break;
+	case SND_SOC_DAIFMT_I2S:
+		val |= AK4104_CONTROL1_DIF0 | AK4104_CONTROL1_DIF1;
+		break;
+	default:
+		dev_err(codec->dev, "invalid dai format\n");
+		return -EINVAL;
+	}
+
+	/* This device can only be slave */
+	if ((format & SND_SOC_DAIFMT_MASTER_MASK) != SND_SOC_DAIFMT_CBS_CFS)
+		return -EINVAL;
+
+	return ak4104_spi_write(codec, AK4104_REG_CONTROL1, val);
+}
+
+static int ak4104_hw_params(struct snd_pcm_substream *substream,
+			    struct snd_pcm_hw_params *params,
+			    struct snd_soc_dai *dai)
+{
+	struct snd_soc_pcm_runtime *rtd = substream->private_data;
+	struct snd_soc_device *socdev = rtd->socdev;
+	struct snd_soc_codec *codec = socdev->card->codec;
+	int val = 0;
+
+	/* set the IEC958 bits: consumer mode, no copyright bit */
+	val |= IEC958_AES0_CON_NOT_COPYRIGHT;
+	ak4104_spi_write(codec, AK4104_REG_CHN_STATUS(0), val);
+
+	val = 0;
+
+	switch (params_rate(params)) {
+	case 44100:
+		val |= IEC958_AES3_CON_FS_44100;
+		break;
+	case 48000:
+		val |= IEC958_AES3_CON_FS_48000;
+		break;
+	case 32000:
+		val |= IEC958_AES3_CON_FS_32000;
+		break;
+	default:
+		dev_err(codec->dev, "unsupported sampling rate\n");
+		return -EINVAL;
+	}
+
+	return ak4104_spi_write(codec, AK4104_REG_CHN_STATUS(3), val);
+}
+
+struct snd_soc_dai ak4104_dai = {
+	.name = DRV_NAME,
+	.playback = {
+		.stream_name = "Playback",
+		.channels_min = 2,
+		.channels_max = 2,
+		.rates = SNDRV_PCM_RATE_44100 |
+			 SNDRV_PCM_RATE_48000 |
+			 SNDRV_PCM_RATE_32000,
+		.formats = SNDRV_PCM_FMTBIT_S16_LE  |
+			   SNDRV_PCM_FMTBIT_S24_3LE |
+			   SNDRV_PCM_FMTBIT_S24_LE
+	},
+	.ops = {
+		.hw_params = ak4104_hw_params,
+		.set_fmt = ak4104_set_dai_fmt,
+	}
+};
+
+static struct snd_soc_codec *ak4104_codec;
+
+static int ak4104_spi_probe(struct spi_device *spi)
+{
+	struct snd_soc_codec *codec;
+	struct ak4104_private *ak4104;
+	int ret, val;
+
+	spi->bits_per_word = 8;
+	spi->mode = SPI_MODE_0;
+	ret = spi_setup(spi);
+	if (ret < 0)
+		return ret;
+
+	ak4104 = kzalloc(sizeof(struct ak4104_private), GFP_KERNEL);
+	if (!ak4104) {
+		dev_err(&spi->dev, "could not allocate codec\n");
+		return -ENOMEM;
+	}
+
+	codec = &ak4104->codec;
+	mutex_init(&codec->mutex);
+	INIT_LIST_HEAD(&codec->dapm_widgets);
+	INIT_LIST_HEAD(&codec->dapm_paths);
+
+	codec->dev = &spi->dev;
+	codec->name = DRV_NAME;
+	codec->owner = THIS_MODULE;
+	codec->dai = &ak4104_dai;
+	codec->num_dai = 1;
+	codec->private_data = ak4104;
+	codec->control_data = spi;
+	codec->reg_cache = ak4104->reg_cache;
+	codec->reg_cache_size = AK4104_NUM_REGS;
+
+	/* read all regs and fill the cache */
+	ret = ak4104_fill_cache(codec);
+	if (ret < 0) {
+		dev_err(&spi->dev, "failed to fill register cache\n");
+		return ret;
+	}
+
+	/* read the 'reserved' register - according to the datasheet, it
+	 * should contain 0x5b. Not a good way to verify the presence of
+	 * the device, but there is no hardware ID register. */
+	if (ak4104_read_reg_cache(codec, AK4104_REG_RESERVED) !=
+					 AK4104_RESERVED_VAL) {
+		ret = -ENODEV;
+		goto error_free_codec;
+	}
+
+	/* set power-up and non-reset bits */
+	val = ak4104_read_reg_cache(codec, AK4104_REG_CONTROL1);
+	val |= AK4104_CONTROL1_PW | AK4104_CONTROL1_RSTN;
+	ret = ak4104_spi_write(codec, AK4104_REG_CONTROL1, val);
+	if (ret < 0)
+		goto error_free_codec;
+
+	/* enable transmitter */
+	val = ak4104_read_reg_cache(codec, AK4104_REG_TX);
+	val |= AK4104_TX_TXE;
+	ret = ak4104_spi_write(codec, AK4104_REG_TX, val);
+	if (ret < 0)
+		goto error_free_codec;
+
+	ak4104_codec = codec;
+	ret = snd_soc_register_dai(&ak4104_dai);
+	if (ret < 0) {
+		dev_err(&spi->dev, "failed to register DAI\n");
+		goto error_free_codec;
+	}
+
+	spi_set_drvdata(spi, ak4104);
+	dev_info(&spi->dev, "SPI device initialized\n");
+	return 0;
+
+error_free_codec:
+	kfree(ak4104);
+	ak4104_dai.dev = NULL;
+	return ret;
+}
+
+static int __devexit ak4104_spi_remove(struct spi_device *spi)
+{
+	int ret, val;
+	struct ak4104_private *ak4104 = spi_get_drvdata(spi);
+
+	val = ak4104_read_reg_cache(&ak4104->codec, AK4104_REG_CONTROL1);
+	if (val < 0)
+		return val;
+
+	/* clear power-up and non-reset bits */
+	val &= ~(AK4104_CONTROL1_PW | AK4104_CONTROL1_RSTN);
+	ret = ak4104_spi_write(&ak4104->codec, AK4104_REG_CONTROL1, val);
+	if (ret < 0)
+		return ret;
+
+	ak4104_codec = NULL;
+	kfree(ak4104);
+	return 0;
+}
+
+static int ak4104_probe(struct platform_device *pdev)
+{
+	struct snd_soc_device *socdev = platform_get_drvdata(pdev);
+	struct snd_soc_codec *codec = ak4104_codec;
+	int ret;
+
+	/* Connect the codec to the socdev.  snd_soc_new_pcms() needs this. */
+	socdev->card->codec = codec;
+
+	/* Register PCMs */
+	ret = snd_soc_new_pcms(socdev, SNDRV_DEFAULT_IDX1, SNDRV_DEFAULT_STR1);
+	if (ret < 0) {
+		dev_err(codec->dev, "failed to create pcms\n");
+		return ret;
+	}
+
+	/* Register the socdev */
+	ret = snd_soc_init_card(socdev);
+	if (ret < 0) {
+		dev_err(codec->dev, "failed to register card\n");
+		snd_soc_free_pcms(socdev);
+		return ret;
+	}
+
+	return 0;
+}
+
+static int ak4104_remove(struct platform_device *pdev)
+{
+	struct snd_soc_device *socdev = platform_get_drvdata(pdev);
+	snd_soc_free_pcms(socdev);
+	return 0;
+};
+
+struct snd_soc_codec_device soc_codec_device_ak4104 = {
+	.probe = 	ak4104_probe,
+	.remove = 	ak4104_remove
+};
+EXPORT_SYMBOL_GPL(soc_codec_device_ak4104);
+
+static struct spi_driver ak4104_spi_driver = {
+	.driver  = {
+		.name   = DRV_NAME,
+		.owner  = THIS_MODULE,
+	},
+	.probe  = ak4104_spi_probe,
+	.remove = __devexit_p(ak4104_spi_remove),
+};
+
+static int __init ak4104_init(void)
+{
+	pr_info("Asahi Kasei AK4104 ALSA SoC Codec Driver\n");
+	return spi_register_driver(&ak4104_spi_driver);
+}
+module_init(ak4104_init);
+
+static void __exit ak4104_exit(void)
+{
+	spi_unregister_driver(&ak4104_spi_driver);
+}
+module_exit(ak4104_exit);
+
+MODULE_AUTHOR("Daniel Mack <daniel@caiaq.de>");
+MODULE_DESCRIPTION("Asahi Kasei AK4104 ALSA SoC driver");
+MODULE_LICENSE("GPL");
+