/*
 * AD5446 SPI DAC driver
 *
 * Copyright 2010 Analog Devices Inc.
 *
 * Licensed under the GPL-2 or later.
 */

#include <linux/interrupt.h>
#include <linux/workqueue.h>
#include <linux/device.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/sysfs.h>
#include <linux/list.h>
#include <linux/spi/spi.h>
#include <linux/i2c.h>
#include <linux/regulator/consumer.h>
#include <linux/err.h>
#include <linux/module.h>

#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>

#define MODE_PWRDWN_1k          0x1
#define MODE_PWRDWN_100k        0x2
#define MODE_PWRDWN_TRISTATE    0x3

/**
 * struct ad5446_state - driver instance specific data
 * @spi:                spi_device
 * @chip_info:          chip model specific constants, available modes etc
 * @reg:                supply regulator
 * @vref_mv:            actual reference voltage used
 */

struct ad5446_state {
        struct device           *dev;
        const struct ad5446_chip_info   *chip_info;
        struct regulator                *reg;
        unsigned short                  vref_mv;
        unsigned                        cached_val;
        unsigned                        pwr_down_mode;
        unsigned                        pwr_down;
};

/**
 * struct ad5446_chip_info - chip specific information
 * @channel:            channel spec for the DAC
 * @int_vref_mv:        AD5620/40/60: the internal reference voltage
 * @write:              chip specific helper function to write to the register
 */

struct ad5446_chip_info {
        struct iio_chan_spec    channel;
        u16                     int_vref_mv;
        int                     (*write)(struct ad5446_state *st, unsigned val);
};

static const char * const ad5446_powerdown_modes[] = {
        "1kohm_to_gnd", "100kohm_to_gnd", "three_state"
};

static int ad5446_set_powerdown_mode(struct iio_dev *indio_dev,
        const struct iio_chan_spec *chan, unsigned int mode)
{
        struct ad5446_state *st = iio_priv(indio_dev);

        st->pwr_down_mode = mode + 1;

        return 0;
}

static int ad5446_get_powerdown_mode(struct iio_dev *indio_dev,
        const struct iio_chan_spec *chan)
{
        struct ad5446_state *st = iio_priv(indio_dev);

        return st->pwr_down_mode - 1;
}

static const struct iio_enum ad5446_powerdown_mode_enum = {
        .items = ad5446_powerdown_modes,
        .num_items = ARRAY_SIZE(ad5446_powerdown_modes),
        .get = ad5446_get_powerdown_mode,
        .set = ad5446_set_powerdown_mode,
};

static ssize_t ad5446_read_dac_powerdown(struct iio_dev *indio_dev,
                                           uintptr_t private,
                                           const struct iio_chan_spec *chan,
                                           char *buf)
{
        struct ad5446_state *st = iio_priv(indio_dev);

        return sprintf(buf, "%d\n", st->pwr_down);
}

static ssize_t ad5446_write_dac_powerdown(struct iio_dev *indio_dev,
                                            uintptr_t private,
                                            const struct iio_chan_spec *chan,
                                            const char *buf, size_t len)
{
        struct ad5446_state *st = iio_priv(indio_dev);
        unsigned int shift;
        unsigned int val;
        bool powerdown;
        int ret;

        ret = strtobool(buf, &powerdown);
        if (ret)
                return ret;

        mutex_lock(&indio_dev->mlock);
        st->pwr_down = powerdown;

        if (st->pwr_down) {
                shift = chan->scan_type.realbits + chan->scan_type.shift;
                val = st->pwr_down_mode << shift;
        } else {
                val = st->cached_val;
        }

        ret = st->chip_info->write(st, val);
        mutex_unlock(&indio_dev->mlock);

        return ret ? ret : len;
}

static const struct iio_chan_spec_ext_info ad5446_ext_info_powerdown[] = {
        {
                .name = "powerdown",
                .read = ad5446_read_dac_powerdown,
                .write = ad5446_write_dac_powerdown,
                .shared = IIO_SEPARATE,
        },
        IIO_ENUM("powerdown_mode", IIO_SEPARATE, &ad5446_powerdown_mode_enum),
        IIO_ENUM_AVAILABLE("powerdown_mode", &ad5446_powerdown_mode_enum),
        { },
};

#define _AD5446_CHANNEL(bits, storage, shift, ext) { \
        .type = IIO_VOLTAGE, \
        .indexed = 1, \
        .output = 1, \
        .channel = 0, \
        .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
        .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
        .scan_type = IIO_ST('u', (bits), (storage), (shift)), \
        .ext_info = (ext), \
}

#define AD5446_CHANNEL(bits, storage, shift) \
        _AD5446_CHANNEL(bits, storage, shift, NULL)

#define AD5446_CHANNEL_POWERDOWN(bits, storage, shift) \
        _AD5446_CHANNEL(bits, storage, shift, ad5446_ext_info_powerdown)

static int ad5446_read_raw(struct iio_dev *indio_dev,
                           struct iio_chan_spec const *chan,
                           int *val,
                           int *val2,
                           long m)
{
        struct ad5446_state *st = iio_priv(indio_dev);

        switch (m) {
        case IIO_CHAN_INFO_RAW:
                *val = st->cached_val;
                return IIO_VAL_INT;
        case IIO_CHAN_INFO_SCALE:
                *val = st->vref_mv;
                *val2 = chan->scan_type.realbits;
                return IIO_VAL_FRACTIONAL_LOG2;
        }
        return -EINVAL;
}

static int ad5446_write_raw(struct iio_dev *indio_dev,
                               struct iio_chan_spec const *chan,
                               int val,
                               int val2,
                               long mask)
{
        struct ad5446_state *st = iio_priv(indio_dev);
        int ret = 0;

        switch (mask) {
        case IIO_CHAN_INFO_RAW:
                if (val >= (1 << chan->scan_type.realbits) || val < 0)
                        return -EINVAL;

                val <<= chan->scan_type.shift;
                mutex_lock(&indio_dev->mlock);
                st->cached_val = val;
                if (!st->pwr_down)
                        ret = st->chip_info->write(st, val);
                mutex_unlock(&indio_dev->mlock);
                break;
        default:
                ret = -EINVAL;
        }

        return ret;
}

static const struct iio_info ad5446_info = {
        .read_raw = ad5446_read_raw,
        .write_raw = ad5446_write_raw,
        .driver_module = THIS_MODULE,
};

static int ad5446_probe(struct device *dev, const char *name,
                        const struct ad5446_chip_info *chip_info)
{
        struct ad5446_state *st;
        struct iio_dev *indio_dev;
        struct regulator *reg;
        int ret, voltage_uv = 0;

        reg = devm_regulator_get(dev, "vcc");
        if (!IS_ERR(reg)) {
                ret = regulator_enable(reg);
                if (ret)
                        return ret;

                ret = regulator_get_voltage(reg);
                if (ret < 0)
                        goto error_disable_reg;

                voltage_uv = ret;
        }

        indio_dev = devm_iio_device_alloc(dev, sizeof(*st));
        if (indio_dev == NULL) {
                ret = -ENOMEM;
                goto error_disable_reg;
        }
        st = iio_priv(indio_dev);
        st->chip_info = chip_info;

        dev_set_drvdata(dev, indio_dev);
        st->reg = reg;
        st->dev = dev;

        /* Establish that the iio_dev is a child of the device */
        indio_dev->dev.parent = dev;
        indio_dev->name = name;
        indio_dev->info = &ad5446_info;
        indio_dev->modes = INDIO_DIRECT_MODE;
        indio_dev->channels = &st->chip_info->channel;
        indio_dev->num_channels = 1;

        st->pwr_down_mode = MODE_PWRDWN_1k;

        if (st->chip_info->int_vref_mv)
                st->vref_mv = st->chip_info->int_vref_mv;
        else if (voltage_uv)
                st->vref_mv = voltage_uv / 1000;
        else
                dev_warn(dev, "reference voltage unspecified\n");

        ret = iio_device_register(indio_dev);
        if (ret)
                goto error_disable_reg;

        return 0;

error_disable_reg:
        if (!IS_ERR(reg))
                regulator_disable(reg);
        return ret;
}

static int ad5446_remove(struct device *dev)
{
        struct iio_dev *indio_dev = dev_get_drvdata(dev);
        struct ad5446_state *st = iio_priv(indio_dev);

        iio_device_unregister(indio_dev);
        if (!IS_ERR(st->reg))
                regulator_disable(st->reg);

        return 0;
}

#if IS_ENABLED(CONFIG_SPI_MASTER)

static int ad5446_write(struct ad5446_state *st, unsigned val)
{
        struct spi_device *spi = to_spi_device(st->dev);
        __be16 data = cpu_to_be16(val);

        return spi_write(spi, &data, sizeof(data));
}

static int ad5660_write(struct ad5446_state *st, unsigned val)
{
        struct spi_device *spi = to_spi_device(st->dev);
        uint8_t data[3];

        data[0] = (val >> 16) & 0xFF;
        data[1] = (val >> 8) & 0xFF;
        data[2] = val & 0xFF;

        return spi_write(spi, data, sizeof(data));
}

/**
 * ad5446_supported_spi_device_ids:
 * The AD5620/40/60 parts are available in different fixed internal reference
 * voltage options. The actual part numbers may look differently
 * (and a bit cryptic), however this style is used to make clear which
 * parts are supported here.
 */
enum ad5446_supported_spi_device_ids {
        ID_AD5300,
        ID_AD5310,
        ID_AD5320,
        ID_AD5444,
        ID_AD5446,
        ID_AD5450,
        ID_AD5451,
        ID_AD5541A,
        ID_AD5512A,
        ID_AD5553,
        ID_AD5601,
        ID_AD5611,
        ID_AD5621,
        ID_AD5641,
        ID_AD5620_2500,
        ID_AD5620_1250,
        ID_AD5640_2500,
        ID_AD5640_1250,
        ID_AD5660_2500,
        ID_AD5660_1250,
        ID_AD5662,
};

static const struct ad5446_chip_info ad5446_spi_chip_info[] = {
        [ID_AD5300] = {
                .channel = AD5446_CHANNEL_POWERDOWN(8, 16, 4),
                .write = ad5446_write,
        },
        [ID_AD5310] = {
                .channel = AD5446_CHANNEL_POWERDOWN(10, 16, 2),
                .write = ad5446_write,
        },
        [ID_AD5320] = {
                .channel = AD5446_CHANNEL_POWERDOWN(12, 16, 0),
                .write = ad5446_write,
        },
        [ID_AD5444] = {
                .channel = AD5446_CHANNEL(12, 16, 2),
                .write = ad5446_write,
        },
        [ID_AD5446] = {
                .channel = AD5446_CHANNEL(14, 16, 0),
                .write = ad5446_write,
        },
        [ID_AD5450] = {
                .channel = AD5446_CHANNEL(8, 16, 6),
                .write = ad5446_write,
        },
        [ID_AD5451] = {
                .channel = AD5446_CHANNEL(10, 16, 4),
                .write = ad5446_write,
        },
        [ID_AD5541A] = {
                .channel = AD5446_CHANNEL(16, 16, 0),
                .write = ad5446_write,
        },
        [ID_AD5512A] = {
                .channel = AD5446_CHANNEL(12, 16, 4),
                .write = ad5446_write,
        },
        [ID_AD5553] = {
                .channel = AD5446_CHANNEL(14, 16, 0),
                .write = ad5446_write,
        },
        [ID_AD5601] = {
                .channel = AD5446_CHANNEL_POWERDOWN(8, 16, 6),
                .write = ad5446_write,
        },
        [ID_AD5611] = {
                .channel = AD5446_CHANNEL_POWERDOWN(10, 16, 4),
                .write = ad5446_write,
        },
        [ID_AD5621] = {
                .channel = AD5446_CHANNEL_POWERDOWN(12, 16, 2),
                .write = ad5446_write,
        },
        [ID_AD5641] = {
                .channel = AD5446_CHANNEL_POWERDOWN(14, 16, 0),
                .write = ad5446_write,
        },
        [ID_AD5620_2500] = {
                .channel = AD5446_CHANNEL_POWERDOWN(12, 16, 2),
                .int_vref_mv = 2500,
                .write = ad5446_write,
        },
        [ID_AD5620_1250] = {
                .channel = AD5446_CHANNEL_POWERDOWN(12, 16, 2),
                .int_vref_mv = 1250,
                .write = ad5446_write,
        },
        [ID_AD5640_2500] = {
                .channel = AD5446_CHANNEL_POWERDOWN(14, 16, 0),
                .int_vref_mv = 2500,
                .write = ad5446_write,
        },
        [ID_AD5640_1250] = {
                .channel = AD5446_CHANNEL_POWERDOWN(14, 16, 0),
                .int_vref_mv = 1250,
                .write = ad5446_write,
        },
        [ID_AD5660_2500] = {
                .channel = AD5446_CHANNEL_POWERDOWN(16, 16, 0),
                .int_vref_mv = 2500,
                .write = ad5660_write,
        },
        [ID_AD5660_1250] = {
                .channel = AD5446_CHANNEL_POWERDOWN(16, 16, 0),
                .int_vref_mv = 1250,
                .write = ad5660_write,
        },
        [ID_AD5662] = {
                .channel = AD5446_CHANNEL_POWERDOWN(16, 16, 0),
                .write = ad5660_write,
        },
};

static const struct spi_device_id ad5446_spi_ids[] = {
        {"ad5300", ID_AD5300},
        {"ad5310", ID_AD5310},
        {"ad5320", ID_AD5320},
        {"ad5444", ID_AD5444},
        {"ad5446", ID_AD5446},
        {"ad5450", ID_AD5450},
        {"ad5451", ID_AD5451},
        {"ad5452", ID_AD5444}, /* ad5452 is compatible to the ad5444 */
        {"ad5453", ID_AD5446}, /* ad5453 is compatible to the ad5446 */
        {"ad5512a", ID_AD5512A},
        {"ad5541a", ID_AD5541A},
        {"ad5542a", ID_AD5541A}, /* ad5541a and ad5542a are compatible */
        {"ad5543", ID_AD5541A}, /* ad5541a and ad5543 are compatible */
        {"ad5553", ID_AD5553},
        {"ad5601", ID_AD5601},
        {"ad5611", ID_AD5611},
        {"ad5621", ID_AD5621},
        {"ad5641", ID_AD5641},
        {"ad5620-2500", ID_AD5620_2500}, /* AD5620/40/60: */
        {"ad5620-1250", ID_AD5620_1250}, /* part numbers may look differently */
        {"ad5640-2500", ID_AD5640_2500},
        {"ad5640-1250", ID_AD5640_1250},
        {"ad5660-2500", ID_AD5660_2500},
        {"ad5660-1250", ID_AD5660_1250},
        {"ad5662", ID_AD5662},
        {}
};
MODULE_DEVICE_TABLE(spi, ad5446_spi_ids);

static int ad5446_spi_probe(struct spi_device *spi)
{
        const struct spi_device_id *id = spi_get_device_id(spi);

        return ad5446_probe(&spi->dev, id->name,
                &ad5446_spi_chip_info[id->driver_data]);
}

static int ad5446_spi_remove(struct spi_device *spi)
{
        return ad5446_remove(&spi->dev);
}

static struct spi_driver ad5446_spi_driver = {
        .driver = {
                .name   = "ad5446",
                .owner  = THIS_MODULE,
        },
        .probe          = ad5446_spi_probe,
        .remove         = ad5446_spi_remove,
        .id_table       = ad5446_spi_ids,
};

static int __init ad5446_spi_register_driver(void)
{
        return spi_register_driver(&ad5446_spi_driver);
}

static void ad5446_spi_unregister_driver(void)
{
        spi_unregister_driver(&ad5446_spi_driver);
}

#else

static inline int ad5446_spi_register_driver(void) { return 0; }
static inline void ad5446_spi_unregister_driver(void) { }

#endif

#if IS_ENABLED(CONFIG_I2C)

static int ad5622_write(struct ad5446_state *st, unsigned val)
{
        struct i2c_client *client = to_i2c_client(st->dev);
        __be16 data = cpu_to_be16(val);

        return i2c_master_send(client, (char *)&data, sizeof(data));
}

/**
 * ad5446_supported_i2c_device_ids:
 * The AD5620/40/60 parts are available in different fixed internal reference
 * voltage options. The actual part numbers may look differently
 * (and a bit cryptic), however this style is used to make clear which
 * parts are supported here.
 */
enum ad5446_supported_i2c_device_ids {
        ID_AD5602,
        ID_AD5612,
        ID_AD5622,
};

static const struct ad5446_chip_info ad5446_i2c_chip_info[] = {
        [ID_AD5602] = {
                .channel = AD5446_CHANNEL_POWERDOWN(8, 16, 4),
                .write = ad5622_write,
        },
        [ID_AD5612] = {
                .channel = AD5446_CHANNEL_POWERDOWN(10, 16, 2),
                .write = ad5622_write,
        },
        [ID_AD5622] = {
                .channel = AD5446_CHANNEL_POWERDOWN(12, 16, 0),
                .write = ad5622_write,
        },
};

static int ad5446_i2c_probe(struct i2c_client *i2c,
                            const struct i2c_device_id *id)
{
        return ad5446_probe(&i2c->dev, id->name,
                &ad5446_i2c_chip_info[id->driver_data]);
}

static int ad5446_i2c_remove(struct i2c_client *i2c)
{
        return ad5446_remove(&i2c->dev);
}

static const struct i2c_device_id ad5446_i2c_ids[] = {
        {"ad5301", ID_AD5602},
        {"ad5311", ID_AD5612},
        {"ad5321", ID_AD5622},
        {"ad5602", ID_AD5602},
        {"ad5612", ID_AD5612},
        {"ad5622", ID_AD5622},
        {}
};
MODULE_DEVICE_TABLE(i2c, ad5446_i2c_ids);

static struct i2c_driver ad5446_i2c_driver = {
        .driver = {
                   .name = "ad5446",
                   .owner = THIS_MODULE,
        },
        .probe = ad5446_i2c_probe,
        .remove = ad5446_i2c_remove,
        .id_table = ad5446_i2c_ids,
};

static int __init ad5446_i2c_register_driver(void)
{
        return i2c_add_driver(&ad5446_i2c_driver);
}

static void __exit ad5446_i2c_unregister_driver(void)
{
        i2c_del_driver(&ad5446_i2c_driver);
}

#else

static inline int ad5446_i2c_register_driver(void) { return 0; }
static inline void ad5446_i2c_unregister_driver(void) { }

#endif

static int __init ad5446_init(void)
{
        int ret;

        ret = ad5446_spi_register_driver();
        if (ret)
                return ret;

        ret = ad5446_i2c_register_driver();
        if (ret) {
                ad5446_spi_unregister_driver();
                return ret;
        }

        return 0;
}
module_init(ad5446_init);

static void __exit ad5446_exit(void)
{
        ad5446_i2c_unregister_driver();
        ad5446_spi_unregister_driver();
}
module_exit(ad5446_exit);

MODULE_AUTHOR("Michael Hennerich <hennerich@blackfin.uclinux.org>");
MODULE_DESCRIPTION("Analog Devices AD5444/AD5446 DAC");
MODULE_LICENSE("GPL v2");