// SPDX-License-Identifier: GPL-2.0-only
/*
 * mcp4725.c - Support for Microchip MCP4725/6
 *
 * Copyright (C) 2012 Peter Meerwald <pmeerw@pmeerw.net>
 *
 * Based on max517 by Roland Stigge <stigge@antcom.de>
 *
 * driver for the Microchip I2C 12-bit digital-to-analog converter (DAC)
 * (7-bit I2C slave address 0x60, the three LSBs can be configured in
 * hardware)
 */

#include <linux/module.h>
#include <linux/i2c.h>
#include <linux/err.h>
#include <linux/delay.h>
#include <linux/regulator/consumer.h>
#include <linux/mod_devicetable.h>
#include <linux/property.h>

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

#include <linux/iio/dac/mcp4725.h>

#define MCP472X_REF_VDD                 0x00
#define MCP472X_REF_VREF_UNBUFFERED     0x02
#define MCP472X_REF_VREF_BUFFERED       0x03

struct mcp4725_chip_info {
        const struct iio_chan_spec *chan_spec;
        u8 dac_reg_offset;
        bool use_ext_ref_voltage;
};

struct mcp4725_data {
        struct i2c_client *client;
        unsigned ref_mode;
        bool vref_buffered;
        u16 dac_value;
        bool powerdown;
        unsigned powerdown_mode;
        struct regulator *vdd_reg;
        struct regulator *vref_reg;
};

static int mcp4725_suspend(struct device *dev)
{
        struct mcp4725_data *data = iio_priv(i2c_get_clientdata(
                to_i2c_client(dev)));
        u8 outbuf[2];
        int ret;

        outbuf[0] = (data->powerdown_mode + 1) << 4;
        outbuf[1] = 0;
        data->powerdown = true;

        ret = i2c_master_send(data->client, outbuf, 2);
        if (ret < 0)
                return ret;
        else if (ret != 2)
                return -EIO;
        return 0;
}

static int mcp4725_resume(struct device *dev)
{
        struct mcp4725_data *data = iio_priv(i2c_get_clientdata(
                to_i2c_client(dev)));
        u8 outbuf[2];
        int ret;

        /* restore previous DAC value */
        outbuf[0] = (data->dac_value >> 8) & 0xf;
        outbuf[1] = data->dac_value & 0xff;
        data->powerdown = false;

        ret = i2c_master_send(data->client, outbuf, 2);
        if (ret < 0)
                return ret;
        else if (ret != 2)
                return -EIO;
        return 0;
}
static DEFINE_SIMPLE_DEV_PM_OPS(mcp4725_pm_ops, mcp4725_suspend,
                                mcp4725_resume);

static ssize_t mcp4725_store_eeprom(struct device *dev,
        struct device_attribute *attr, const char *buf, size_t len)
{
        struct iio_dev *indio_dev = dev_to_iio_dev(dev);
        struct mcp4725_data *data = iio_priv(indio_dev);
        int tries = 20;
        u8 inoutbuf[3];
        bool state;
        int ret;

        ret = kstrtobool(buf, &state);
        if (ret < 0)
                return ret;

        if (!state)
                return 0;

        inoutbuf[0] = 0x60; /* write EEPROM */
        inoutbuf[0] |= data->ref_mode << 3;
        inoutbuf[0] |= data->powerdown ? ((data->powerdown_mode + 1) << 1) : 0;
        inoutbuf[1] = data->dac_value >> 4;
        inoutbuf[2] = (data->dac_value & 0xf) << 4;

        ret = i2c_master_send(data->client, inoutbuf, 3);
        if (ret < 0)
                return ret;
        else if (ret != 3)
                return -EIO;

        /* wait for write complete, takes up to 50ms */
        while (tries--) {
                msleep(20);
                ret = i2c_master_recv(data->client, inoutbuf, 3);
                if (ret < 0)
                        return ret;
                else if (ret != 3)
                        return -EIO;

                if (inoutbuf[0] & 0x80)
                        break;
        }

        if (tries < 0) {
                dev_err(&data->client->dev,
                        "mcp4725_store_eeprom() failed, incomplete\n");
                return -EIO;
        }

        return len;
}

static IIO_DEVICE_ATTR(store_eeprom, S_IWUSR, NULL, mcp4725_store_eeprom, 0);

static struct attribute *mcp4725_attributes[] = {
        &iio_dev_attr_store_eeprom.dev_attr.attr,
        NULL,
};

static const struct attribute_group mcp4725_attribute_group = {
        .attrs = mcp4725_attributes,
};

static const char * const mcp4725_powerdown_modes[] = {
        "1kohm_to_gnd",
        "100kohm_to_gnd",
        "500kohm_to_gnd"
};

static const char * const mcp4726_powerdown_modes[] = {
        "1kohm_to_gnd",
        "125kohm_to_gnd",
        "640kohm_to_gnd"
};

static int mcp4725_get_powerdown_mode(struct iio_dev *indio_dev,
        const struct iio_chan_spec *chan)
{
        struct mcp4725_data *data = iio_priv(indio_dev);

        return data->powerdown_mode;
}

static int mcp4725_set_powerdown_mode(struct iio_dev *indio_dev,
        const struct iio_chan_spec *chan, unsigned mode)
{
        struct mcp4725_data *data = iio_priv(indio_dev);

        data->powerdown_mode = mode;

        return 0;
}

static ssize_t mcp4725_read_powerdown(struct iio_dev *indio_dev,
        uintptr_t private, const struct iio_chan_spec *chan, char *buf)
{
        struct mcp4725_data *data = iio_priv(indio_dev);

        return sysfs_emit(buf, "%d\n", data->powerdown);
}

static ssize_t mcp4725_write_powerdown(struct iio_dev *indio_dev,
         uintptr_t private, const struct iio_chan_spec *chan,
         const char *buf, size_t len)
{
        struct mcp4725_data *data = iio_priv(indio_dev);
        bool state;
        int ret;

        ret = kstrtobool(buf, &state);
        if (ret)
                return ret;

        if (state)
                ret = mcp4725_suspend(&data->client->dev);
        else
                ret = mcp4725_resume(&data->client->dev);
        if (ret < 0)
                return ret;

        return len;
}

enum chip_id {
        MCP4725,
        MCP4726,
};

static const struct iio_enum mcp472x_powerdown_mode_enum[] = {
        [MCP4725] = {
                .items = mcp4725_powerdown_modes,
                .num_items = ARRAY_SIZE(mcp4725_powerdown_modes),
                .get = mcp4725_get_powerdown_mode,
                .set = mcp4725_set_powerdown_mode,
        },
        [MCP4726] = {
                .items = mcp4726_powerdown_modes,
                .num_items = ARRAY_SIZE(mcp4726_powerdown_modes),
                .get = mcp4725_get_powerdown_mode,
                .set = mcp4725_set_powerdown_mode,
        },
};

static const struct iio_chan_spec_ext_info mcp4725_ext_info[] = {
        {
                .name = "powerdown",
                .read = mcp4725_read_powerdown,
                .write = mcp4725_write_powerdown,
                .shared = IIO_SEPARATE,
        },
        IIO_ENUM("powerdown_mode", IIO_SEPARATE,
                        &mcp472x_powerdown_mode_enum[MCP4725]),
        IIO_ENUM_AVAILABLE("powerdown_mode", IIO_SHARED_BY_TYPE,
                           &mcp472x_powerdown_mode_enum[MCP4725]),
        { }
};

static const struct iio_chan_spec_ext_info mcp4726_ext_info[] = {
        {
                .name = "powerdown",
                .read = mcp4725_read_powerdown,
                .write = mcp4725_write_powerdown,
                .shared = IIO_SEPARATE,
        },
        IIO_ENUM("powerdown_mode", IIO_SEPARATE,
                        &mcp472x_powerdown_mode_enum[MCP4726]),
        IIO_ENUM_AVAILABLE("powerdown_mode", IIO_SHARED_BY_TYPE,
                           &mcp472x_powerdown_mode_enum[MCP4726]),
        { }
};

static const struct iio_chan_spec mcp472x_channel[] = {
        [MCP4725] = {
                .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),
                .ext_info       = mcp4725_ext_info,
        },
        [MCP4726] = {
                .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),
                .ext_info       = mcp4726_ext_info,
        },
};

static int mcp4725_set_value(struct iio_dev *indio_dev, int val)
{
        struct mcp4725_data *data = iio_priv(indio_dev);
        u8 outbuf[2];
        int ret;

        if (val >= (1 << 12) || val < 0)
                return -EINVAL;

        outbuf[0] = (val >> 8) & 0xf;
        outbuf[1] = val & 0xff;

        ret = i2c_master_send(data->client, outbuf, 2);
        if (ret < 0)
                return ret;
        else if (ret != 2)
                return -EIO;
        else
                return 0;
}

static int mcp4726_set_cfg(struct iio_dev *indio_dev)
{
        struct mcp4725_data *data = iio_priv(indio_dev);
        u8 outbuf[3];
        int ret;

        outbuf[0] = 0x40;
        outbuf[0] |= data->ref_mode << 3;
        if (data->powerdown)
                outbuf[0] |= data->powerdown << 1;
        outbuf[1] = data->dac_value >> 4;
        outbuf[2] = (data->dac_value & 0xf) << 4;

        ret = i2c_master_send(data->client, outbuf, 3);
        if (ret < 0)
                return ret;
        else if (ret != 3)
                return -EIO;
        else
                return 0;
}

static int mcp4725_read_raw(struct iio_dev *indio_dev,
                           struct iio_chan_spec const *chan,
                           int *val, int *val2, long mask)
{
        struct mcp4725_data *data = iio_priv(indio_dev);
        int ret;

        switch (mask) {
        case IIO_CHAN_INFO_RAW:
                *val = data->dac_value;
                return IIO_VAL_INT;
        case IIO_CHAN_INFO_SCALE:
                if (data->ref_mode == MCP472X_REF_VDD)
                        ret = regulator_get_voltage(data->vdd_reg);
                else
                        ret = regulator_get_voltage(data->vref_reg);

                if (ret < 0)
                        return ret;

                *val = ret / 1000;
                *val2 = 12;
                return IIO_VAL_FRACTIONAL_LOG2;
        }
        return -EINVAL;
}

static int mcp4725_write_raw(struct iio_dev *indio_dev,
                               struct iio_chan_spec const *chan,
                               int val, int val2, long mask)
{
        struct mcp4725_data *data = iio_priv(indio_dev);
        int ret;

        switch (mask) {
        case IIO_CHAN_INFO_RAW:
                ret = mcp4725_set_value(indio_dev, val);
                data->dac_value = val;
                break;
        default:
                ret = -EINVAL;
                break;
        }

        return ret;
}

static const struct iio_info mcp4725_info = {
        .read_raw = mcp4725_read_raw,
        .write_raw = mcp4725_write_raw,
        .attrs = &mcp4725_attribute_group,
};

static int mcp4725_probe_dt(struct device *dev,
                            struct mcp4725_platform_data *pdata)
{
        /* check if is the vref-supply defined */
        pdata->use_vref = device_property_present(dev, "vref-supply");
        pdata->vref_buffered =
                device_property_read_bool(dev, "microchip,vref-buffered");

        return 0;
}

static int mcp4725_probe(struct i2c_client *client)
{
        const struct i2c_device_id *id = i2c_client_get_device_id(client);
        const struct mcp4725_chip_info *info;
        struct mcp4725_data *data;
        struct iio_dev *indio_dev;
        struct mcp4725_platform_data *pdata, pdata_dt;
        u8 inbuf[4];
        u8 pd;
        u8 ref;
        int err;

        indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
        if (indio_dev == NULL)
                return -ENOMEM;
        data = iio_priv(indio_dev);
        i2c_set_clientdata(client, indio_dev);
        data->client = client;
        info = i2c_get_match_data(client);
        pdata = dev_get_platdata(&client->dev);

        if (!pdata) {
                err = mcp4725_probe_dt(&client->dev, &pdata_dt);
                if (err) {
                        dev_err(&client->dev,
                                "invalid platform or devicetree data");
                        return err;
                }
                pdata = &pdata_dt;
        }

        if (info->use_ext_ref_voltage && pdata->use_vref) {
                dev_err(&client->dev,
                        "external reference is unavailable on MCP4725");
                return -EINVAL;
        }

        if (!pdata->use_vref && pdata->vref_buffered) {
                dev_err(&client->dev,
                        "buffering is unavailable on the internal reference");
                return -EINVAL;
        }

        if (!pdata->use_vref)
                data->ref_mode = MCP472X_REF_VDD;
        else
                data->ref_mode = pdata->vref_buffered ?
                        MCP472X_REF_VREF_BUFFERED :
                        MCP472X_REF_VREF_UNBUFFERED;

        data->vdd_reg = devm_regulator_get(&client->dev, "vdd");
        if (IS_ERR(data->vdd_reg))
                return PTR_ERR(data->vdd_reg);

        err = regulator_enable(data->vdd_reg);
        if (err)
                return err;

        if (pdata->use_vref) {
                data->vref_reg = devm_regulator_get(&client->dev, "vref");
                if (IS_ERR(data->vref_reg)) {
                        err = PTR_ERR(data->vref_reg);
                        goto err_disable_vdd_reg;
                }

                err = regulator_enable(data->vref_reg);
                if (err)
                        goto err_disable_vdd_reg;
        }

        indio_dev->name = id->name;
        indio_dev->info = &mcp4725_info;
        indio_dev->channels = info->chan_spec;
        indio_dev->num_channels = 1;
        indio_dev->modes = INDIO_DIRECT_MODE;

        /* read current DAC value and settings */
        err = i2c_master_recv(client, inbuf, info->dac_reg_offset);

        if (err < 0) {
                dev_err(&client->dev, "failed to read DAC value");
                goto err_disable_vref_reg;
        }
        pd = (inbuf[0] >> 1) & 0x3;
        data->powerdown = pd > 0;
        data->powerdown_mode = pd ? pd - 1 : 2; /* largest resistor to gnd */
        data->dac_value = (inbuf[1] << 4) | (inbuf[2] >> 4);
        if (!info->use_ext_ref_voltage)
                ref = (inbuf[3] >> 3) & 0x3;

        if (!info->use_ext_ref_voltage && ref != data->ref_mode) {
                dev_info(&client->dev,
                        "voltage reference mode differs (conf: %u, eeprom: %u), setting %u",
                        data->ref_mode, ref, data->ref_mode);
                err = mcp4726_set_cfg(indio_dev);
                if (err < 0)
                        goto err_disable_vref_reg;
        }
 
        err = iio_device_register(indio_dev);
        if (err)
                goto err_disable_vref_reg;

        return 0;

err_disable_vref_reg:
        if (data->vref_reg)
                regulator_disable(data->vref_reg);

err_disable_vdd_reg:
        regulator_disable(data->vdd_reg);

        return err;
}

static void mcp4725_remove(struct i2c_client *client)
{
        struct iio_dev *indio_dev = i2c_get_clientdata(client);
        struct mcp4725_data *data = iio_priv(indio_dev);

        iio_device_unregister(indio_dev);

        if (data->vref_reg)
                regulator_disable(data->vref_reg);
        regulator_disable(data->vdd_reg);
}

static const struct mcp4725_chip_info mcp4725 = {
        .chan_spec = &mcp472x_channel[MCP4725],
        .dac_reg_offset = 3,
        .use_ext_ref_voltage = true,
};

static const struct mcp4725_chip_info mcp4726 = {
        .chan_spec = &mcp472x_channel[MCP4726],
        .dac_reg_offset = 4,
};

static const struct i2c_device_id mcp4725_id[] = {
        { "mcp4725", (kernel_ulong_t)&mcp4725 },
        { "mcp4726", (kernel_ulong_t)&mcp4726 },
        { }
};
MODULE_DEVICE_TABLE(i2c, mcp4725_id);

static const struct of_device_id mcp4725_of_match[] = {
        {
                .compatible = "microchip,mcp4725",
                .data = &mcp4725
        },
        {
                .compatible = "microchip,mcp4726",
                .data = &mcp4726
        },
        { }
};
MODULE_DEVICE_TABLE(of, mcp4725_of_match);

static struct i2c_driver mcp4725_driver = {
        .driver = {
                .name   = "mcp4725",
                .of_match_table = mcp4725_of_match,
                .pm     = pm_sleep_ptr(&mcp4725_pm_ops),
        },
        .probe          = mcp4725_probe,
        .remove         = mcp4725_remove,
        .id_table       = mcp4725_id,
};
module_i2c_driver(mcp4725_driver);

MODULE_AUTHOR("Peter Meerwald <pmeerw@pmeerw.net>");
MODULE_DESCRIPTION("MCP4725/6 12-bit DAC");
MODULE_LICENSE("GPL");