/*
 * 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 <linux/slab.h>
#include <sound/core.h>
#include <sound/soc.h>
#include <sound/initval.h>
#include <linux/spi/spi.h>
#include <sound/asoundef.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-codec"

struct ak4104_private {
	enum snd_soc_control_type control_type;
	void *control_data;
};

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->driver->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->driver->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->driver->reg_cache_size)
		return -EINVAL;

	/* only write to the hardware if value has changed */
	if (cache[reg] != value) {
		u8 tmp[2] = { (reg & AK4104_REG_MASK) | AK4104_WRITE, 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_codec *codec = rtd->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);
}

static struct snd_soc_dai_ops ak4101_dai_ops = {
	.hw_params = ak4104_hw_params,
	.set_fmt = ak4104_set_dai_fmt,
};

static struct snd_soc_dai_driver ak4104_dai = {
	.name = "ak4104-hifi",
	.playback = {
		.stream_name = "Playback",
		.channels_min = 2,
		.channels_max = 2,
		.rates = SNDRV_PCM_RATE_8000_192000,
		.formats = SNDRV_PCM_FMTBIT_S16_LE  |
			   SNDRV_PCM_FMTBIT_S24_3LE |
			   SNDRV_PCM_FMTBIT_S24_LE
	},
	.ops = &ak4101_dai_ops,
};

static int ak4104_probe(struct snd_soc_codec *codec)
{
	struct ak4104_private *ak4104 = snd_soc_codec_get_drvdata(codec);
	int ret, val;

	codec->control_data = ak4104->control_data;

	/* read all regs and fill the cache */
	ret = ak4104_fill_cache(codec);
	if (ret < 0) {
		dev_err(codec->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)
		return -ENODEV;

	/* 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)
		return ret;

	/* 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)
		return ret;

	dev_info(codec->dev, "SPI device initialized\n");
	return 0;
}

static int ak4104_remove(struct snd_soc_codec *codec)
{
	int val, ret;

	val = ak4104_read_reg_cache(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(codec, AK4104_REG_CONTROL1, val);

	return ret;
}

static struct snd_soc_codec_driver soc_codec_device_ak4104 = {
	.probe =	ak4104_probe,
	.remove =	ak4104_remove,
	.reg_cache_size = AK4104_NUM_REGS,
	.reg_word_size = sizeof(u16),
};

static int ak4104_spi_probe(struct spi_device *spi)
{
	struct ak4104_private *ak4104;
	int ret;

	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 == NULL)
		return -ENOMEM;

	ak4104->control_data = spi;
	ak4104->control_type = SND_SOC_SPI;
	spi_set_drvdata(spi, ak4104);

	ret = snd_soc_register_codec(&spi->dev,
			&soc_codec_device_ak4104, &ak4104_dai, 1);
	if (ret < 0)
		kfree(ak4104);
	return ret;
}

static int __devexit ak4104_spi_remove(struct spi_device *spi)
{
	snd_soc_unregister_codec(&spi->dev);
	kfree(spi_get_drvdata(spi));
	return 0;
}

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");