// SPDX-License-Identifier: GPL-2.0
/*
 * Synaptics AS370 SoC Hardware Monitoring Driver
 *
 * Copyright (C) 2018 Synaptics Incorporated
 * Author: Jisheng Zhang <jszhang@kernel.org>
 */

#include <linux/bitops.h>
#include <linux/hwmon.h>
#include <linux/init.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/mod_devicetable.h>
#include <linux/platform_device.h>

#define CTRL            0x0
#define  PD             BIT(0)
#define  EN             BIT(1)
#define  T_SEL          BIT(2)
#define  V_SEL          BIT(3)
#define  NMOS_SEL       BIT(8)
#define  PMOS_SEL       BIT(9)
#define STS             0x4
#define  BN_MASK        GENMASK(11, 0)
#define  EOC            BIT(12)

struct as370_hwmon {
        void __iomem *base;
};

static void init_pvt(struct as370_hwmon *hwmon)
{
        u32 val;
        void __iomem *addr = hwmon->base + CTRL;

        val = PD;
        writel_relaxed(val, addr);
        val |= T_SEL;
        writel_relaxed(val, addr);
        val |= EN;
        writel_relaxed(val, addr);
        val &= ~PD;
        writel_relaxed(val, addr);
}

static int as370_hwmon_read(struct device *dev, enum hwmon_sensor_types type,
                            u32 attr, int channel, long *temp)
{
        int val;
        struct as370_hwmon *hwmon = dev_get_drvdata(dev);

        switch (attr) {
        case hwmon_temp_input:
                val = readl_relaxed(hwmon->base + STS) & BN_MASK;
                *temp = DIV_ROUND_CLOSEST(val * 251802, 4096) - 85525;
                break;
        default:
                return -EOPNOTSUPP;
        }

        return 0;
}

static umode_t
as370_hwmon_is_visible(const void *data, enum hwmon_sensor_types type,
                       u32 attr, int channel)
{
        if (type != hwmon_temp)
                return 0;

        switch (attr) {
        case hwmon_temp_input:
                return 0444;
        default:
                return 0;
        }
}

static const struct hwmon_channel_info * const as370_hwmon_info[] = {
        HWMON_CHANNEL_INFO(temp, HWMON_T_INPUT),
        NULL
};

static const struct hwmon_ops as370_hwmon_ops = {
        .is_visible = as370_hwmon_is_visible,
        .read = as370_hwmon_read,
};

static const struct hwmon_chip_info as370_chip_info = {
        .ops = &as370_hwmon_ops,
        .info = as370_hwmon_info,
};

static int as370_hwmon_probe(struct platform_device *pdev)
{
        struct device *hwmon_dev;
        struct as370_hwmon *hwmon;
        struct device *dev = &pdev->dev;

        hwmon = devm_kzalloc(dev, sizeof(*hwmon), GFP_KERNEL);
        if (!hwmon)
                return -ENOMEM;

        hwmon->base = devm_platform_ioremap_resource(pdev, 0);
        if (IS_ERR(hwmon->base))
                return PTR_ERR(hwmon->base);

        init_pvt(hwmon);

        hwmon_dev = devm_hwmon_device_register_with_info(dev,
                                                         "as370",
                                                         hwmon,
                                                         &as370_chip_info,
                                                         NULL);
        return PTR_ERR_OR_ZERO(hwmon_dev);
}

static const struct of_device_id as370_hwmon_match[] = {
        { .compatible = "syna,as370-hwmon" },
        {},
};
MODULE_DEVICE_TABLE(of, as370_hwmon_match);

static struct platform_driver as370_hwmon_driver = {
        .probe = as370_hwmon_probe,
        .driver = {
                .name = "as370-hwmon",
                .of_match_table = as370_hwmon_match,
        },
};
module_platform_driver(as370_hwmon_driver);

MODULE_AUTHOR("Jisheng Zhang<jszhang@kernel.org>");
MODULE_DESCRIPTION("Synaptics AS370 SoC hardware monitor");
MODULE_LICENSE("GPL v2");