// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * max1619.c - Part of lm_sensors, Linux kernel modules for hardware
 *             monitoring
 * Copyright (C) 2003-2004 Oleksij Rempel <bug-track@fisher-privat.net>
 *                         Jean Delvare <jdelvare@suse.de>
 *
 * Based on the lm90 driver. The MAX1619 is a sensor chip made by Maxim.
 * It reports up to two temperatures (its own plus up to
 * one external one). Complete datasheet can be
 * obtained from Maxim's website at:
 *   http://pdfserv.maxim-ic.com/en/ds/MAX1619.pdf
 */

#include <linux/err.h>
#include <linux/hwmon.h>
#include <linux/i2c.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/regmap.h>
#include <linux/util_macros.h>

static const unsigned short normal_i2c[] = {
        0x18, 0x19, 0x1a, 0x29, 0x2a, 0x2b, 0x4c, 0x4d, 0x4e, I2C_CLIENT_END };

#define MAX1619_REG_LOCAL_TEMP          0x00
#define MAX1619_REG_REMOTE_TEMP         0x01
#define MAX1619_REG_STATUS              0x02
#define MAX1619_REG_CONFIG              0x03
#define MAX1619_REG_CONVRATE            0x04
#define MAX1619_REG_REMOTE_HIGH         0x07
#define MAX1619_REG_REMOTE_LOW          0x08
#define MAX1619_REG_REMOTE_CRIT         0x10
#define MAX1619_REG_REMOTE_CRIT_HYST    0x11
#define MAX1619_REG_MAN_ID              0xFE
#define MAX1619_REG_CHIP_ID             0xFF

static int get_alarms(struct regmap *regmap)
{
        static u32 regs[2] = { MAX1619_REG_STATUS, MAX1619_REG_CONFIG };
        u8 regdata[2];
        int ret;

        ret = regmap_multi_reg_read(regmap, regs, regdata, 2);
        if (ret)
                return ret;

        /* OVERT status bit may be reversed */
        if (!(regdata[1] & 0x20))
                regdata[0] ^= 0x02;

        return regdata[0] & 0x1e;
}

static int max1619_temp_read(struct regmap *regmap, u32 attr, int channel, long *val)
{
        int reg = -1, alarm_bit = 0;
        u32 temp;
        int ret;

        switch (attr) {
        case hwmon_temp_input:
                reg = channel ? MAX1619_REG_REMOTE_TEMP : MAX1619_REG_LOCAL_TEMP;
                break;
        case hwmon_temp_min:
                reg = MAX1619_REG_REMOTE_LOW;
                break;
        case hwmon_temp_max:
                reg = MAX1619_REG_REMOTE_HIGH;
                break;
        case hwmon_temp_crit:
                reg = MAX1619_REG_REMOTE_CRIT;
                break;
        case hwmon_temp_crit_hyst:
                reg = MAX1619_REG_REMOTE_CRIT_HYST;
                break;
        case hwmon_temp_min_alarm:
                alarm_bit = 3;
                break;
        case hwmon_temp_max_alarm:
                alarm_bit = 4;
                break;
        case hwmon_temp_crit_alarm:
                alarm_bit = 1;
                break;
        case hwmon_temp_fault:
                alarm_bit = 2;
                break;
        default:
                return -EOPNOTSUPP;
        }
        if (reg >= 0) {
                ret = regmap_read(regmap, reg, &temp);
                if (ret < 0)
                        return ret;
                *val = sign_extend32(temp, 7) * 1000;
        } else {
                ret = get_alarms(regmap);
                if (ret < 0)
                        return ret;
                *val = !!(ret & BIT(alarm_bit));
        }
        return 0;
}

static u16 update_intervals[] = { 16000, 8000, 4000, 2000, 1000, 500, 250, 125 };

static int max1619_chip_read(struct regmap *regmap, u32 attr, long *val)
{
        int alarms, ret;
        u32 regval;

        switch (attr) {
        case hwmon_chip_update_interval:
                ret = regmap_read(regmap, MAX1619_REG_CONVRATE, &regval);
                if (ret < 0)
                        return ret;
                *val = update_intervals[regval & 7];
                break;
        case hwmon_chip_alarms:
                alarms = get_alarms(regmap);
                if (alarms < 0)
                        return alarms;
                *val = alarms;
                break;
        default:
                return -EOPNOTSUPP;
        }
        return 0;
}

static int max1619_read(struct device *dev, enum hwmon_sensor_types type,
                        u32 attr, int channel, long *val)
{
        struct regmap *regmap = dev_get_drvdata(dev);

        switch (type) {
        case hwmon_chip:
                return max1619_chip_read(regmap, attr, val);
        case hwmon_temp:
                return max1619_temp_read(regmap, attr, channel, val);
        default:
                return -EOPNOTSUPP;
        }
}

static int max1619_chip_write(struct regmap *regmap, u32 attr, long val)
{
        switch (attr) {
        case hwmon_chip_update_interval:
                val = find_closest_descending(val, update_intervals, ARRAY_SIZE(update_intervals));
                return regmap_write(regmap, MAX1619_REG_CONVRATE, val);
        default:
                return -EOPNOTSUPP;
        }
}

static int max1619_temp_write(struct regmap *regmap,
                              u32 attr, int channel, long val)
{
        int reg;

        switch (attr) {
        case hwmon_temp_min:
                reg = MAX1619_REG_REMOTE_LOW;
                break;
        case hwmon_temp_max:
                reg = MAX1619_REG_REMOTE_HIGH;
                break;
        case hwmon_temp_crit:
                reg = MAX1619_REG_REMOTE_CRIT;
                break;
        case hwmon_temp_crit_hyst:
                reg = MAX1619_REG_REMOTE_CRIT_HYST;
                break;
        default:
                return -EOPNOTSUPP;
        }
        val = DIV_ROUND_CLOSEST(clamp_val(val, -128000, 127000), 1000);
        return regmap_write(regmap, reg, val);
}

static int max1619_write(struct device *dev, enum hwmon_sensor_types type,
                         u32 attr, int channel, long val)
{
        struct regmap *regmap = dev_get_drvdata(dev);

        switch (type) {
        case hwmon_chip:
                return max1619_chip_write(regmap, attr, val);
        case hwmon_temp:
                return max1619_temp_write(regmap, attr, channel, val);
        default:
                return -EOPNOTSUPP;
        }
}

static umode_t max1619_is_visible(const void *_data, enum hwmon_sensor_types type,
                                  u32 attr, int channel)
{
        switch (type) {
        case hwmon_chip:
                switch (attr) {
                case hwmon_chip_update_interval:
                        return 0644;
                case hwmon_chip_alarms:
                        return 0444;
                default:
                        break;
                }
                break;
        case hwmon_temp:
                switch (attr) {
                case hwmon_temp_input:
                        return 0444;
                case hwmon_temp_min:
                case hwmon_temp_max:
                case hwmon_temp_crit:
                case hwmon_temp_crit_hyst:
                        return 0644;
                case hwmon_temp_min_alarm:
                case hwmon_temp_max_alarm:
                case hwmon_temp_crit_alarm:
                case hwmon_temp_fault:
                        return 0444;
                default:
                        break;
                }
                break;
        default:
                break;
        }
        return 0;
}

static const struct hwmon_channel_info * const max1619_info[] = {
        HWMON_CHANNEL_INFO(chip, HWMON_C_ALARMS | HWMON_C_UPDATE_INTERVAL),
        HWMON_CHANNEL_INFO(temp,
                           HWMON_T_INPUT,
                           HWMON_T_INPUT | HWMON_T_MIN | HWMON_T_MAX |
                           HWMON_T_CRIT | HWMON_T_CRIT_HYST |
                           HWMON_T_MIN_ALARM | HWMON_T_MAX_ALARM |
                           HWMON_T_CRIT_ALARM | HWMON_T_FAULT),
        NULL
};

static const struct hwmon_ops max1619_hwmon_ops = {
        .is_visible = max1619_is_visible,
        .read = max1619_read,
        .write = max1619_write,
};

static const struct hwmon_chip_info max1619_chip_info = {
        .ops = &max1619_hwmon_ops,
        .info = max1619_info,
};

/* Return 0 if detection is successful, -ENODEV otherwise */
static int max1619_detect(struct i2c_client *client,
                          struct i2c_board_info *info)
{
        struct i2c_adapter *adapter = client->adapter;
        int regval;

        if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
                return -ENODEV;

        regval = i2c_smbus_read_byte_data(client, MAX1619_REG_CONFIG);
        if (regval < 0 || (regval & 0x03))
                return -ENODEV;
        regval = i2c_smbus_read_byte_data(client, MAX1619_REG_CONVRATE);
        if (regval < 0 || regval > 0x07)
                return -ENODEV;
        regval = i2c_smbus_read_byte_data(client, MAX1619_REG_STATUS);
        if (regval < 0 || (regval & 0x61))
                return -ENODEV;

        regval = i2c_smbus_read_byte_data(client, MAX1619_REG_MAN_ID);
        if (regval != 0x4d)
                return -ENODEV;
        regval = i2c_smbus_read_byte_data(client, MAX1619_REG_CHIP_ID);
        if (regval != 0x04)
                return -ENODEV;

        strscpy(info->type, "max1619", I2C_NAME_SIZE);

        return 0;
}

static int max1619_init_chip(struct regmap *regmap)
{
        int ret;

        ret = regmap_write(regmap, MAX1619_REG_CONVRATE, 5);    /* 2 Hz */
        if (ret)
                return ret;

        /* Start conversions */
        return regmap_clear_bits(regmap, MAX1619_REG_CONFIG, 0x40);
}

/* regmap */

static int max1619_reg_read(void *context, unsigned int reg, unsigned int *val)
{
        int ret;

        ret = i2c_smbus_read_byte_data(context, reg);
        if (ret < 0)
                return ret;

        *val = ret;
        return 0;
}

static int max1619_reg_write(void *context, unsigned int reg, unsigned int val)
{
        int offset = reg < MAX1619_REG_REMOTE_CRIT ? 6 : 2;

        return i2c_smbus_write_byte_data(context, reg + offset, val);
}

static bool max1619_regmap_is_volatile(struct device *dev, unsigned int reg)
{
        return reg <= MAX1619_REG_STATUS;
}

static bool max1619_regmap_is_writeable(struct device *dev, unsigned int reg)
{
        return reg > MAX1619_REG_STATUS && reg <= MAX1619_REG_REMOTE_CRIT_HYST;
}

static const struct regmap_config max1619_regmap_config = {
        .reg_bits = 8,
        .val_bits = 8,
        .max_register = MAX1619_REG_REMOTE_CRIT_HYST,
        .cache_type = REGCACHE_MAPLE,
        .volatile_reg = max1619_regmap_is_volatile,
        .writeable_reg = max1619_regmap_is_writeable,
};

static const struct regmap_bus max1619_regmap_bus = {
        .reg_write = max1619_reg_write,
        .reg_read = max1619_reg_read,
};

static int max1619_probe(struct i2c_client *client)
{
        struct device *dev = &client->dev;
        struct device *hwmon_dev;
        struct regmap *regmap;
        int ret;

        regmap = devm_regmap_init(dev, &max1619_regmap_bus, client,
                                  &max1619_regmap_config);
        if (IS_ERR(regmap))
                return PTR_ERR(regmap);

        ret = max1619_init_chip(regmap);
        if (ret)
                return ret;

        hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name,
                                                         regmap, &max1619_chip_info, NULL);
        return PTR_ERR_OR_ZERO(hwmon_dev);
}

static const struct i2c_device_id max1619_id[] = {
        { "max1619" },
        { }
};
MODULE_DEVICE_TABLE(i2c, max1619_id);

#ifdef CONFIG_OF
static const struct of_device_id max1619_of_match[] = {
        { .compatible = "maxim,max1619", },
        {},
};

MODULE_DEVICE_TABLE(of, max1619_of_match);
#endif

static struct i2c_driver max1619_driver = {
        .class          = I2C_CLASS_HWMON,
        .driver = {
                .name   = "max1619",
                .of_match_table = of_match_ptr(max1619_of_match),
        },
        .probe          = max1619_probe,
        .id_table       = max1619_id,
        .detect         = max1619_detect,
        .address_list   = normal_i2c,
};

module_i2c_driver(max1619_driver);

MODULE_AUTHOR("Oleksij Rempel <bug-track@fisher-privat.net>, Jean Delvare <jdelvare@suse.de>");
MODULE_DESCRIPTION("MAX1619 sensor driver");
MODULE_LICENSE("GPL");