// SPDX-License-Identifier: GPL-2.0+
/*
 * Functions to access SY3686A power management chip temperature
 *
 * Copyright (C) 2021 reMarkable AS - http://www.remarkable.com/
 *
 * Authors: Lars Ivar Miljeteig <lars.ivar.miljeteig@remarkable.com>
 *          Alistair Francis <alistair@alistair23.me>
 */

#include <linux/err.h>
#include <linux/hwmon.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/regmap.h>
#include <linux/regulator/machine.h>

#include <linux/mfd/sy7636a.h>

static int sy7636a_read(struct device *dev, enum hwmon_sensor_types type,
                        u32 attr, int channel, long *temp)
{
        struct regmap *regmap = dev_get_drvdata(dev);
        int ret, reg_val;

        ret = regmap_read(regmap,
                          SY7636A_REG_TERMISTOR_READOUT, &reg_val);
        if (ret)
                return ret;

        *temp = reg_val * 1000;

        return 0;
}

static umode_t sy7636a_is_visible(const void *data,
                                  enum hwmon_sensor_types type,
                                  u32 attr, int channel)
{
        if (type != hwmon_temp)
                return 0;

        if (attr != hwmon_temp_input)
                return 0;

        return 0444;
}

static const struct hwmon_ops sy7636a_hwmon_ops = {
        .is_visible = sy7636a_is_visible,
        .read = sy7636a_read,
};

static const struct hwmon_channel_info * const sy7636a_info[] = {
        HWMON_CHANNEL_INFO(chip, HWMON_C_REGISTER_TZ),
        HWMON_CHANNEL_INFO(temp, HWMON_T_INPUT),
        NULL
};

static const struct hwmon_chip_info sy7636a_chip_info = {
        .ops = &sy7636a_hwmon_ops,
        .info = sy7636a_info,
};

static int sy7636a_sensor_probe(struct platform_device *pdev)
{
        struct regmap *regmap = dev_get_regmap(pdev->dev.parent, NULL);
        struct device *hwmon_dev;
        int err;

        if (!regmap)
                return -EPROBE_DEFER;

        err = devm_regulator_get_enable(&pdev->dev, "vcom");
        if (err)
                return err;

        hwmon_dev = devm_hwmon_device_register_with_info(&pdev->dev,
                                                         "sy7636a_temperature", regmap,
                                                         &sy7636a_chip_info, NULL);

        if (IS_ERR(hwmon_dev)) {
                err = PTR_ERR(hwmon_dev);
                dev_err(&pdev->dev, "Unable to register hwmon device, returned %d\n", err);
                return err;
        }

        return 0;
}

static struct platform_driver sy7636a_sensor_driver = {
        .probe = sy7636a_sensor_probe,
        .driver = {
                .name = "sy7636a-temperature",
        },
};
module_platform_driver(sy7636a_sensor_driver);

MODULE_DESCRIPTION("SY7636A sensor driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:sy7636a-temperature");