// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *  max517.c - Support for Maxim MAX517, MAX518 and MAX519
 *
 *  Copyright (C) 2010, 2011 Roland Stigge <stigge@antcom.de>
 */

#include <linux/module.h>
#include <linux/slab.h>
#include <linux/jiffies.h>
#include <linux/i2c.h>
#include <linux/err.h>

#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>
#include <linux/iio/dac/max517.h>

/* Commands */
#define COMMAND_CHANNEL0        0x00
#define COMMAND_CHANNEL1        0x01 /* for MAX518 and MAX519 */
#define COMMAND_PD              0x08 /* Power Down */

enum max517_device_ids {
        ID_MAX517,
        ID_MAX518,
        ID_MAX519,
        ID_MAX520,
        ID_MAX521,
};

struct max517_data {
        struct i2c_client       *client;
        unsigned short          vref_mv[8];
};

/*
 * channel: bit 0: channel 1
 *          bit 1: channel 2
 * (this way, it's possible to set both channels at once)
 */
static int max517_set_value(struct iio_dev *indio_dev,
        long val, int channel)
{
        struct max517_data *data = iio_priv(indio_dev);
        struct i2c_client *client = data->client;
        u8 outbuf[2];
        int res;

        if (val < 0 || val > 255)
                return -EINVAL;

        outbuf[0] = channel;
        outbuf[1] = val;

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

static int max517_read_raw(struct iio_dev *indio_dev,
                           struct iio_chan_spec const *chan,
                           int *val,
                           int *val2,
                           long m)
{
        struct max517_data *data = iio_priv(indio_dev);

        switch (m) {
        case IIO_CHAN_INFO_SCALE:
                /* Corresponds to Vref / 2^(bits) */
                *val = data->vref_mv[chan->channel];
                *val2 = 8;
                return IIO_VAL_FRACTIONAL_LOG2;
        default:
                break;
        }
        return -EINVAL;
}

static int max517_write_raw(struct iio_dev *indio_dev,
        struct iio_chan_spec const *chan, int val, int val2, long mask)
{
        int ret;

        switch (mask) {
        case IIO_CHAN_INFO_RAW:
                ret = max517_set_value(indio_dev, val, chan->channel);
                break;
        default:
                ret = -EINVAL;
                break;
        }

        return ret;
}

static int max517_suspend(struct device *dev)
{
        u8 outbuf = COMMAND_PD;

        return i2c_master_send(to_i2c_client(dev), &outbuf, 1);
}

static int max517_resume(struct device *dev)
{
        u8 outbuf = 0;

        return i2c_master_send(to_i2c_client(dev), &outbuf, 1);
}

static DEFINE_SIMPLE_DEV_PM_OPS(max517_pm_ops, max517_suspend, max517_resume);

static const struct iio_info max517_info = {
        .read_raw = max517_read_raw,
        .write_raw = max517_write_raw,
};

#define MAX517_CHANNEL(chan) {                          \
        .type = IIO_VOLTAGE,                            \
        .indexed = 1,                                   \
        .output = 1,                                    \
        .channel = (chan),                              \
        .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |  \
        BIT(IIO_CHAN_INFO_SCALE),                       \
}

static const struct iio_chan_spec max517_channels[] = {
        MAX517_CHANNEL(0),
        MAX517_CHANNEL(1),
        MAX517_CHANNEL(2),
        MAX517_CHANNEL(3),
        MAX517_CHANNEL(4),
        MAX517_CHANNEL(5),
        MAX517_CHANNEL(6),
        MAX517_CHANNEL(7),
};

static int max517_probe(struct i2c_client *client)
{
        const struct max517_platform_data *platform_data = dev_get_platdata(&client->dev);
        const struct i2c_device_id *id = i2c_client_get_device_id(client);
        struct max517_data *data;
        struct iio_dev *indio_dev;
        int chan;

        indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
        if (!indio_dev)
                return -ENOMEM;
        data = iio_priv(indio_dev);
        data->client = client;

        switch (id->driver_data) {
        case ID_MAX521:
                indio_dev->num_channels = 8;
                break;
        case ID_MAX520:
                indio_dev->num_channels = 4;
                break;
        case ID_MAX519:
        case ID_MAX518:
                indio_dev->num_channels = 2;
                break;
        default:  /* single channel for MAX517 */
                indio_dev->num_channels = 1;
                break;
        }
        indio_dev->channels = max517_channels;
        indio_dev->modes = INDIO_DIRECT_MODE;
        indio_dev->info = &max517_info;

        /*
         * Reference voltage on MAX518 and default is 5V, else take vref_mv
         * from platform_data
         */
        for (chan = 0; chan < indio_dev->num_channels; chan++) {
                if (id->driver_data == ID_MAX518 || !platform_data)
                        data->vref_mv[chan] = 5000; /* mV */
                else
                        data->vref_mv[chan] = platform_data->vref_mv[chan];
        }

        return devm_iio_device_register(&client->dev, indio_dev);
}

static const struct i2c_device_id max517_id[] = {
        { .name = "max517", .driver_data = ID_MAX517 },
        { .name = "max518", .driver_data = ID_MAX518 },
        { .name = "max519", .driver_data = ID_MAX519 },
        { .name = "max520", .driver_data = ID_MAX520 },
        { .name = "max521", .driver_data = ID_MAX521 },
        { }
};
MODULE_DEVICE_TABLE(i2c, max517_id);

static struct i2c_driver max517_driver = {
        .driver = {
                .name   = "max517",
                .pm     = pm_sleep_ptr(&max517_pm_ops),
        },
        .probe          = max517_probe,
        .id_table       = max517_id,
};
module_i2c_driver(max517_driver);

MODULE_AUTHOR("Roland Stigge <stigge@antcom.de>");
MODULE_DESCRIPTION("MAX517/518/519/520/521 8-bit DAC");
MODULE_LICENSE("GPL");