/*
 * soc-cache.c  --  ASoC register cache helpers
 *
 * Copyright 2009 Wolfson Microelectronics PLC.
 *
 * Author: Mark Brown <broonie@opensource.wolfsonmicro.com>
 *
 *  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/i2c.h>
#include <linux/spi/spi.h>
#include <sound/soc.h>

static unsigned int snd_soc_7_9_read(struct snd_soc_codec *codec,
                                     unsigned int reg)
{
        u16 *cache = codec->reg_cache;
        if (reg >= codec->reg_cache_size)
                return -1;
        return cache[reg];
}

static int snd_soc_7_9_write(struct snd_soc_codec *codec, unsigned int reg,
                             unsigned int value)
{
        u16 *cache = codec->reg_cache;
        u8 data[2];
        int ret;

        BUG_ON(codec->volatile_register);

        data[0] = (reg << 1) | ((value >> 8) & 0x0001);
        data[1] = value & 0x00ff;

        if (reg < codec->reg_cache_size)
                cache[reg] = value;
        ret = codec->hw_write(codec->control_data, data, 2);
        if (ret == 2)
                return 0;
        if (ret < 0)
                return ret;
        else
                return -EIO;
}

#if defined(CONFIG_SPI_MASTER)
static int snd_soc_7_9_spi_write(void *control_data, const char *data,
                                 int len)
{
        struct spi_device *spi = control_data;
        struct spi_transfer t;
        struct spi_message m;
        u8 msg[2];

        if (len <= 0)
                return 0;

        msg[0] = data[0];
        msg[1] = data[1];

        spi_message_init(&m);
        memset(&t, 0, (sizeof t));

        t.tx_buf = &msg[0];
        t.len = len;

        spi_message_add_tail(&t, &m);
        spi_sync(spi, &m);

        return len;
}
#else
#define snd_soc_7_9_spi_write NULL
#endif

static int snd_soc_8_16_write(struct snd_soc_codec *codec, unsigned int reg,
                              unsigned int value)
{
        u16 *reg_cache = codec->reg_cache;
        u8 data[3];

        data[0] = reg;
        data[1] = (value >> 8) & 0xff;
        data[2] = value & 0xff;

        if (!snd_soc_codec_volatile_register(codec, reg))
                reg_cache[reg] = value;

        if (codec->hw_write(codec->control_data, data, 3) == 3)
                return 0;
        else
                return -EIO;
}

static unsigned int snd_soc_8_16_read(struct snd_soc_codec *codec,
                                      unsigned int reg)
{
        u16 *cache = codec->reg_cache;

        if (reg >= codec->reg_cache_size ||
            snd_soc_codec_volatile_register(codec, reg))
                return codec->hw_read(codec, reg);
        else
                return cache[reg];
}

#if defined(CONFIG_I2C) || (defined(CONFIG_I2C_MODULE) && defined(MODULE))
static unsigned int snd_soc_8_16_read_i2c(struct snd_soc_codec *codec,
                                          unsigned int r)
{
        struct i2c_msg xfer[2];
        u8 reg = r;
        u16 data;
        int ret;
        struct i2c_client *client = codec->control_data;

        /* Write register */
        xfer[0].addr = client->addr;
        xfer[0].flags = 0;
        xfer[0].len = 1;
        xfer[0].buf = &reg;

        /* Read data */
        xfer[1].addr = client->addr;
        xfer[1].flags = I2C_M_RD;
        xfer[1].len = 2;
        xfer[1].buf = (u8 *)&data;

        ret = i2c_transfer(client->adapter, xfer, 2);
        if (ret != 2) {
                dev_err(&client->dev, "i2c_transfer() returned %d\n", ret);
                return 0;
        }

        return (data >> 8) | ((data & 0xff) << 8);
}
#else
#define snd_soc_8_16_read_i2c NULL
#endif

static struct {
        int addr_bits;
        int data_bits;
        int (*write)(struct snd_soc_codec *codec, unsigned int, unsigned int);
        int (*spi_write)(void *, const char *, int);
        unsigned int (*read)(struct snd_soc_codec *, unsigned int);
        unsigned int (*i2c_read)(struct snd_soc_codec *, unsigned int);
} io_types[] = {
        { 7, 9, snd_soc_7_9_write, snd_soc_7_9_spi_write, snd_soc_7_9_read },
        { 8, 16, snd_soc_8_16_write, NULL, snd_soc_8_16_read,
          snd_soc_8_16_read_i2c },
};

/**
 * snd_soc_codec_set_cache_io: Set up standard I/O functions.
 *
 * @codec: CODEC to configure.
 * @type: Type of cache.
 * @addr_bits: Number of bits of register address data.
 * @data_bits: Number of bits of data per register.
 * @control: Control bus used.
 *
 * Register formats are frequently shared between many I2C and SPI
 * devices.  In order to promote code reuse the ASoC core provides
 * some standard implementations of CODEC read and write operations
 * which can be set up using this function.
 *
 * The caller is responsible for allocating and initialising the
 * actual cache.
 *
 * Note that at present this code cannot be used by CODECs with
 * volatile registers.
 */
int snd_soc_codec_set_cache_io(struct snd_soc_codec *codec,
                               int addr_bits, int data_bits,
                               enum snd_soc_control_type control)
{
        int i;

        for (i = 0; i < ARRAY_SIZE(io_types); i++)
                if (io_types[i].addr_bits == addr_bits &&
                    io_types[i].data_bits == data_bits)
                        break;
        if (i == ARRAY_SIZE(io_types)) {
                printk(KERN_ERR
                       "No I/O functions for %d bit address %d bit data\n",
                       addr_bits, data_bits);
                return -EINVAL;
        }

        codec->write = io_types[i].write;
        codec->read = io_types[i].read;

        switch (control) {
        case SND_SOC_CUSTOM:
                break;

        case SND_SOC_I2C:
#if defined(CONFIG_I2C) || (defined(CONFIG_I2C_MODULE) && defined(MODULE))
                codec->hw_write = (hw_write_t)i2c_master_send;
#endif
                if (io_types[i].i2c_read)
                        codec->hw_read = io_types[i].i2c_read;
                break;

        case SND_SOC_SPI:
                if (io_types[i].spi_write)
                        codec->hw_write = io_types[i].spi_write;
                break;
        }

        return 0;
}
EXPORT_SYMBOL_GPL(snd_soc_codec_set_cache_io);