// SPDX-License-Identifier: GPL-2.0-only
/*
 * ltc2497-core.c - Common code for Analog Devices/Linear Technology
 * LTC2496 and LTC2497 ADCs
 *
 * Copyright (C) 2017 Analog Devices Inc.
 */

#include <linux/delay.h>
#include <linux/iio/iio.h>
#include <linux/iio/driver.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/regulator/consumer.h>

#include "ltc2497.h"

#define LTC2497_SGL                     BIT(4)
#define LTC2497_DIFF                    0
#define LTC2497_SIGN                    BIT(3)

static int ltc2497core_wait_conv(struct ltc2497core_driverdata *ddata)
{
        s64 time_elapsed;

        time_elapsed = ktime_ms_delta(ktime_get(), ddata->time_prev);

        if (time_elapsed < LTC2497_CONVERSION_TIME_MS) {
                /* delay if conversion time not passed
                 * since last read or write
                 */
                if (msleep_interruptible(
                    LTC2497_CONVERSION_TIME_MS - time_elapsed))
                        return -ERESTARTSYS;

                return 0;
        }

        if (time_elapsed - LTC2497_CONVERSION_TIME_MS <= 0) {
                /* We're in automatic mode -
                 * so the last reading is still not outdated
                 */
                return 0;
        }

        return 1;
}

static int ltc2497core_read(struct ltc2497core_driverdata *ddata, u8 address, int *val)
{
        int ret;

        ret = ltc2497core_wait_conv(ddata);
        if (ret < 0)
                return ret;

        if (ret || ddata->addr_prev != address) {
                ret = ddata->result_and_measure(ddata, address, NULL);
                if (ret < 0)
                        return ret;
                ddata->addr_prev = address;

                if (msleep_interruptible(LTC2497_CONVERSION_TIME_MS))
                        return -ERESTARTSYS;
        }

        ret = ddata->result_and_measure(ddata, address, val);
        if (ret < 0)
                return ret;

        ddata->time_prev = ktime_get();

        return ret;
}

static int ltc2497core_read_raw(struct iio_dev *indio_dev,
                            struct iio_chan_spec const *chan,
                            int *val, int *val2, long mask)
{
        struct ltc2497core_driverdata *ddata = iio_priv(indio_dev);
        int ret;

        switch (mask) {
        case IIO_CHAN_INFO_RAW:
                mutex_lock(&ddata->lock);
                ret = ltc2497core_read(ddata, chan->address, val);
                mutex_unlock(&ddata->lock);
                if (ret < 0)
                        return ret;

                return IIO_VAL_INT;

        case IIO_CHAN_INFO_SCALE:
                ret = regulator_get_voltage(ddata->ref);
                if (ret < 0)
                        return ret;

                *val = ret / 1000;
                *val2 = ddata->chip_info->resolution + 1;

                return IIO_VAL_FRACTIONAL_LOG2;

        default:
                return -EINVAL;
        }
}

#define LTC2497_CHAN(_chan, _addr, _ds_name) { \
        .type = IIO_VOLTAGE, \
        .indexed = 1, \
        .channel = (_chan), \
        .address = (_addr | (_chan / 2) | ((_chan & 1) ? LTC2497_SIGN : 0)), \
        .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
        .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
        .datasheet_name = (_ds_name), \
}

#define LTC2497_CHAN_DIFF(_chan, _addr) { \
        .type = IIO_VOLTAGE, \
        .indexed = 1, \
        .channel = (_chan) * 2 + ((_addr) & LTC2497_SIGN ? 1 : 0), \
        .channel2 = (_chan) * 2 + ((_addr) & LTC2497_SIGN ? 0 : 1),\
        .address = (_addr | _chan), \
        .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
        .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
        .differential = 1, \
}

static const struct iio_chan_spec ltc2497core_channel[] = {
        LTC2497_CHAN(0, LTC2497_SGL, "CH0"),
        LTC2497_CHAN(1, LTC2497_SGL, "CH1"),
        LTC2497_CHAN(2, LTC2497_SGL, "CH2"),
        LTC2497_CHAN(3, LTC2497_SGL, "CH3"),
        LTC2497_CHAN(4, LTC2497_SGL, "CH4"),
        LTC2497_CHAN(5, LTC2497_SGL, "CH5"),
        LTC2497_CHAN(6, LTC2497_SGL, "CH6"),
        LTC2497_CHAN(7, LTC2497_SGL, "CH7"),
        LTC2497_CHAN(8, LTC2497_SGL, "CH8"),
        LTC2497_CHAN(9, LTC2497_SGL, "CH9"),
        LTC2497_CHAN(10, LTC2497_SGL, "CH10"),
        LTC2497_CHAN(11, LTC2497_SGL, "CH11"),
        LTC2497_CHAN(12, LTC2497_SGL, "CH12"),
        LTC2497_CHAN(13, LTC2497_SGL, "CH13"),
        LTC2497_CHAN(14, LTC2497_SGL, "CH14"),
        LTC2497_CHAN(15, LTC2497_SGL, "CH15"),
        LTC2497_CHAN_DIFF(0, LTC2497_DIFF),
        LTC2497_CHAN_DIFF(1, LTC2497_DIFF),
        LTC2497_CHAN_DIFF(2, LTC2497_DIFF),
        LTC2497_CHAN_DIFF(3, LTC2497_DIFF),
        LTC2497_CHAN_DIFF(4, LTC2497_DIFF),
        LTC2497_CHAN_DIFF(5, LTC2497_DIFF),
        LTC2497_CHAN_DIFF(6, LTC2497_DIFF),
        LTC2497_CHAN_DIFF(7, LTC2497_DIFF),
        LTC2497_CHAN_DIFF(0, LTC2497_DIFF | LTC2497_SIGN),
        LTC2497_CHAN_DIFF(1, LTC2497_DIFF | LTC2497_SIGN),
        LTC2497_CHAN_DIFF(2, LTC2497_DIFF | LTC2497_SIGN),
        LTC2497_CHAN_DIFF(3, LTC2497_DIFF | LTC2497_SIGN),
        LTC2497_CHAN_DIFF(4, LTC2497_DIFF | LTC2497_SIGN),
        LTC2497_CHAN_DIFF(5, LTC2497_DIFF | LTC2497_SIGN),
        LTC2497_CHAN_DIFF(6, LTC2497_DIFF | LTC2497_SIGN),
        LTC2497_CHAN_DIFF(7, LTC2497_DIFF | LTC2497_SIGN),
};

static const struct iio_info ltc2497core_info = {
        .read_raw = ltc2497core_read_raw,
};

int ltc2497core_probe(struct device *dev, struct iio_dev *indio_dev)
{
        struct ltc2497core_driverdata *ddata = iio_priv(indio_dev);
        struct iio_map *plat_data = dev_get_platdata(dev);
        int ret;

        /*
         * Keep using dev_name() for the iio_dev's name on some of the parts,
         * since updating it would result in a ABI breakage.
         */
        if (ddata->chip_info->name)
                indio_dev->name = ddata->chip_info->name;
        else
                indio_dev->name = dev_name(dev);

        indio_dev->info = &ltc2497core_info;
        indio_dev->modes = INDIO_DIRECT_MODE;
        indio_dev->channels = ltc2497core_channel;
        indio_dev->num_channels = ARRAY_SIZE(ltc2497core_channel);

        ret = ddata->result_and_measure(ddata, LTC2497_CONFIG_DEFAULT, NULL);
        if (ret < 0)
                return ret;

        ddata->ref = devm_regulator_get(dev, "vref");
        if (IS_ERR(ddata->ref))
                return dev_err_probe(dev, PTR_ERR(ddata->ref),
                                     "Failed to get vref regulator\n");

        ret = regulator_enable(ddata->ref);
        if (ret < 0) {
                dev_err(dev, "Failed to enable vref regulator: %pe\n",
                        ERR_PTR(ret));
                return ret;
        }

        ret = iio_map_array_register(indio_dev, plat_data);
        if (ret) {
                dev_err(&indio_dev->dev, "iio map err: %d\n", ret);
                goto err_regulator_disable;
        }

        ddata->addr_prev = LTC2497_CONFIG_DEFAULT;
        ddata->time_prev = ktime_get();

        mutex_init(&ddata->lock);

        ret = iio_device_register(indio_dev);
        if (ret < 0)
                goto err_array_unregister;

        return 0;

err_array_unregister:
        iio_map_array_unregister(indio_dev);

err_regulator_disable:
        regulator_disable(ddata->ref);

        return ret;
}
EXPORT_SYMBOL_NS(ltc2497core_probe, "LTC2497");

void ltc2497core_remove(struct iio_dev *indio_dev)
{
        struct ltc2497core_driverdata *ddata = iio_priv(indio_dev);

        iio_device_unregister(indio_dev);

        iio_map_array_unregister(indio_dev);

        regulator_disable(ddata->ref);
}
EXPORT_SYMBOL_NS(ltc2497core_remove, "LTC2497");

MODULE_DESCRIPTION("common code for LTC2496/LTC2497 drivers");
MODULE_LICENSE("GPL v2");