// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Copyright (C) 2011 Alexander Stein <alexander.stein@systec-electronic.com>
 *
 * The LM95245 is a sensor chip made by TI / National Semiconductor.
 * It reports up to two temperatures (its own plus an external one).
 *
 * This driver is based on lm95241.c
 */

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

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

/* LM95245 registers */
/* general registers */
#define LM95245_REG_RW_CONFIG1          0x03
#define LM95245_REG_RW_CONVERS_RATE     0x04
#define LM95245_REG_W_ONE_SHOT          0x0F

/* diode configuration */
#define LM95245_REG_RW_CONFIG2          0xBF
#define LM95245_REG_RW_REMOTE_OFFH      0x11
#define LM95245_REG_RW_REMOTE_OFFL      0x12

/* status registers */
#define LM95245_REG_R_STATUS1           0x02
#define LM95245_REG_R_STATUS2           0x33

/* limit registers */
#define LM95245_REG_RW_REMOTE_OS_LIMIT          0x07
#define LM95245_REG_RW_LOCAL_OS_TCRIT_LIMIT     0x20
#define LM95245_REG_RW_REMOTE_TCRIT_LIMIT       0x19
#define LM95245_REG_RW_COMMON_HYSTERESIS        0x21

/* temperature signed */
#define LM95245_REG_R_LOCAL_TEMPH_S     0x00
#define LM95245_REG_R_LOCAL_TEMPL_S     0x30
#define LM95245_REG_R_REMOTE_TEMPH_S    0x01
#define LM95245_REG_R_REMOTE_TEMPL_S    0x10
/* temperature unsigned */
#define LM95245_REG_R_REMOTE_TEMPH_U    0x31
#define LM95245_REG_R_REMOTE_TEMPL_U    0x32

/* id registers */
#define LM95245_REG_R_MAN_ID            0xFE
#define LM95245_REG_R_CHIP_ID           0xFF

/* LM95245 specific bitfields */
#define CFG_STOP                0x40
#define CFG_REMOTE_TCRIT_MASK   0x10
#define CFG_REMOTE_OS_MASK      0x08
#define CFG_LOCAL_TCRIT_MASK    0x04
#define CFG_LOCAL_OS_MASK       0x02

#define CFG2_OS_A0              0x40
#define CFG2_DIODE_FAULT_OS     0x20
#define CFG2_DIODE_FAULT_TCRIT  0x10
#define CFG2_REMOTE_TT          0x08
#define CFG2_REMOTE_FILTER_DIS  0x00
#define CFG2_REMOTE_FILTER_EN   0x06

/* conversation rate in ms */
#define RATE_CR0063     0x00
#define RATE_CR0364     0x01
#define RATE_CR1000     0x02
#define RATE_CR2500     0x03

#define STATUS1_ROS             0x10
#define STATUS1_DIODE_FAULT     0x04
#define STATUS1_RTCRIT          0x02
#define STATUS1_LOC             0x01

#define MANUFACTURER_ID         0x01
#define LM95235_REVISION        0xB1
#define LM95245_REVISION        0xB3

/* Client data (each client gets its own) */
struct lm95245_data {
        struct regmap *regmap;
        int interval;   /* in msecs */
};

/* Conversions */
static int temp_from_reg_unsigned(u8 val_h, u8 val_l)
{
        return val_h * 1000 + val_l * 1000 / 256;
}

static int temp_from_reg_signed(u8 val_h, u8 val_l)
{
        if (val_h & 0x80)
                return (val_h - 0x100) * 1000;
        return temp_from_reg_unsigned(val_h, val_l);
}

static int lm95245_read_conversion_rate(struct lm95245_data *data)
{
        unsigned int rate;
        int ret;

        ret = regmap_read(data->regmap, LM95245_REG_RW_CONVERS_RATE, &rate);
        if (ret < 0)
                return ret;

        switch (rate) {
        case RATE_CR0063:
                data->interval = 63;
                break;
        case RATE_CR0364:
                data->interval = 364;
                break;
        case RATE_CR1000:
                data->interval = 1000;
                break;
        case RATE_CR2500:
        default:
                data->interval = 2500;
                break;
        }
        return 0;
}

static int lm95245_set_conversion_rate(struct lm95245_data *data, long interval)
{
        int ret, rate;

        if (interval <= 63) {
                interval = 63;
                rate = RATE_CR0063;
        } else if (interval <= 364) {
                interval = 364;
                rate = RATE_CR0364;
        } else if (interval <= 1000) {
                interval = 1000;
                rate = RATE_CR1000;
        } else {
                interval = 2500;
                rate = RATE_CR2500;
        }

        ret = regmap_write(data->regmap, LM95245_REG_RW_CONVERS_RATE, rate);
        if (ret < 0)
                return ret;

        data->interval = interval;
        return 0;
}

static int lm95245_read_temp(struct device *dev, u32 attr, int channel,
                             long *val)
{
        struct lm95245_data *data = dev_get_drvdata(dev);
        struct regmap *regmap = data->regmap;
        unsigned int regs[2];
        unsigned int regval;
        u8 regvals[2];
        int ret;

        switch (attr) {
        case hwmon_temp_input:
                regs[0] = channel ? LM95245_REG_R_REMOTE_TEMPL_S :
                                    LM95245_REG_R_LOCAL_TEMPL_S;
                regs[1] = channel ? LM95245_REG_R_REMOTE_TEMPH_S :
                                    LM95245_REG_R_LOCAL_TEMPH_S;
                ret = regmap_multi_reg_read(regmap, regs, regvals, 2);
                if (ret < 0)
                        return ret;
                /*
                 * Local temp is always signed.
                 * Remote temp has both signed and unsigned data.
                 * Use signed calculation for remote if signed bit is set
                 * or if reported temperature is below signed limit.
                 */
                if (!channel || (regvals[1] & 0x80) || regvals[1] < 0x7f) {
                        *val = temp_from_reg_signed(regvals[1], regvals[0]);
                        return 0;
                }
                ret = regmap_bulk_read(regmap, LM95245_REG_R_REMOTE_TEMPH_U, regvals, 2);
                if (ret)
                        return ret;
                *val = temp_from_reg_unsigned(regvals[0], regvals[1]);
                return 0;
        case hwmon_temp_max:
                ret = regmap_read(regmap, LM95245_REG_RW_REMOTE_OS_LIMIT,
                                  &regval);
                if (ret < 0)
                        return ret;
                *val = regval * 1000;
                return 0;
        case hwmon_temp_crit:
                regs[0] = channel ? LM95245_REG_RW_REMOTE_TCRIT_LIMIT :
                                    LM95245_REG_RW_LOCAL_OS_TCRIT_LIMIT;
                ret = regmap_read(regmap, regs[0], &regval);
                if (ret < 0)
                        return ret;
                *val = regval * 1000;
                return 0;
        case hwmon_temp_max_hyst:
                regs[0] = LM95245_REG_RW_REMOTE_OS_LIMIT;
                regs[1] = LM95245_REG_RW_COMMON_HYSTERESIS;
                ret = regmap_multi_reg_read(regmap, regs, regvals, 2);
                if (ret < 0)
                        return ret;
                *val = (regvals[0] - regvals[1]) * 1000;
                return 0;
        case hwmon_temp_crit_hyst:
                regs[0] = channel ? LM95245_REG_RW_REMOTE_TCRIT_LIMIT :
                                    LM95245_REG_RW_LOCAL_OS_TCRIT_LIMIT;
                regs[1] = LM95245_REG_RW_COMMON_HYSTERESIS;

                ret = regmap_multi_reg_read(regmap, regs, regvals, 2);
                if (ret < 0)
                        return ret;
                *val = (regvals[0] - regvals[1]) * 1000;
                return 0;
        case hwmon_temp_type:
                ret = regmap_read(regmap, LM95245_REG_RW_CONFIG2, &regval);
                if (ret < 0)
                        return ret;
                *val = (regval & CFG2_REMOTE_TT) ? 1 : 2;
                return 0;
        case hwmon_temp_offset:
                ret = regmap_bulk_read(regmap, LM95245_REG_RW_REMOTE_OFFH, regvals, 2);
                if (ret < 0)
                        return ret;
                *val = temp_from_reg_signed(regvals[0], regvals[1]);
                return 0;
        case hwmon_temp_max_alarm:
                ret = regmap_read(regmap, LM95245_REG_R_STATUS1, &regval);
                if (ret < 0)
                        return ret;
                *val = !!(regval & STATUS1_ROS);
                return 0;
        case hwmon_temp_crit_alarm:
                ret = regmap_read(regmap, LM95245_REG_R_STATUS1, &regval);
                if (ret < 0)
                        return ret;
                *val = !!(regval & (channel ? STATUS1_RTCRIT : STATUS1_LOC));
                return 0;
        case hwmon_temp_fault:
                ret = regmap_read(regmap, LM95245_REG_R_STATUS1, &regval);
                if (ret < 0)
                        return ret;
                *val = !!(regval & STATUS1_DIODE_FAULT);
                return 0;
        default:
                return -EOPNOTSUPP;
        }
}

static int lm95245_write_temp(struct device *dev, u32 attr, int channel,
                              long val)
{
        struct lm95245_data *data = dev_get_drvdata(dev);
        struct regmap *regmap = data->regmap;
        unsigned int regval;
        u8 regvals[2];
        int ret, reg;

        switch (attr) {
        case hwmon_temp_max:
                val = clamp_val(val / 1000, 0, 255);
                ret = regmap_write(regmap, LM95245_REG_RW_REMOTE_OS_LIMIT, val);
                return ret;
        case hwmon_temp_crit:
                reg = channel ? LM95245_REG_RW_REMOTE_TCRIT_LIMIT :
                                LM95245_REG_RW_LOCAL_OS_TCRIT_LIMIT;
                val = clamp_val(val / 1000, 0, channel ? 255 : 127);
                ret = regmap_write(regmap, reg, val);
                return ret;
        case hwmon_temp_crit_hyst:
                ret = regmap_read(regmap, LM95245_REG_RW_LOCAL_OS_TCRIT_LIMIT,
                                  &regval);
                if (ret < 0)
                        return ret;
                /* Clamp to reasonable range to prevent overflow */
                val = clamp_val(val, -1000000, 1000000);
                val = regval - val / 1000;
                val = clamp_val(val, 0, 31);
                ret = regmap_write(regmap, LM95245_REG_RW_COMMON_HYSTERESIS,
                                   val);
                return ret;
        case hwmon_temp_offset:
                val = clamp_val(val, -128000, 127875);
                val = val * 256 / 1000;
                regvals[0] = val >> 8;
                regvals[1] = val & 0xe0;

                ret = regmap_bulk_write(regmap, LM95245_REG_RW_REMOTE_OFFH, regvals, 2);
                return ret;
        case hwmon_temp_type:
                if (val != 1 && val != 2)
                        return -EINVAL;
                ret = regmap_update_bits(regmap, LM95245_REG_RW_CONFIG2,
                                         CFG2_REMOTE_TT,
                                         val == 1 ? CFG2_REMOTE_TT : 0);
                return ret;
        default:
                return -EOPNOTSUPP;
        }
}

static int lm95245_read_chip(struct device *dev, u32 attr, int channel,
                             long *val)
{
        struct lm95245_data *data = dev_get_drvdata(dev);

        switch (attr) {
        case hwmon_chip_update_interval:
                *val = data->interval;
                return 0;
        default:
                return -EOPNOTSUPP;
        }
}

static int lm95245_write_chip(struct device *dev, u32 attr, int channel,
                              long val)
{
        struct lm95245_data *data = dev_get_drvdata(dev);

        switch (attr) {
        case hwmon_chip_update_interval:
                return lm95245_set_conversion_rate(data, val);
        default:
                return -EOPNOTSUPP;
        }
}

static int lm95245_read(struct device *dev, enum hwmon_sensor_types type,
                        u32 attr, int channel, long *val)
{
        switch (type) {
        case hwmon_chip:
                return lm95245_read_chip(dev, attr, channel, val);
        case hwmon_temp:
                return lm95245_read_temp(dev, attr, channel, val);
        default:
                return -EOPNOTSUPP;
        }
}

static int lm95245_write(struct device *dev, enum hwmon_sensor_types type,
                         u32 attr, int channel, long val)
{
        switch (type) {
        case hwmon_chip:
                return lm95245_write_chip(dev, attr, channel, val);
        case hwmon_temp:
                return lm95245_write_temp(dev, attr, channel, val);
        default:
                return -EOPNOTSUPP;
        }
}

static umode_t lm95245_temp_is_visible(const void *data, u32 attr, int channel)
{
        switch (attr) {
        case hwmon_temp_input:
        case hwmon_temp_max_alarm:
        case hwmon_temp_max_hyst:
        case hwmon_temp_crit_alarm:
        case hwmon_temp_fault:
                return 0444;
        case hwmon_temp_type:
        case hwmon_temp_max:
        case hwmon_temp_crit:
        case hwmon_temp_offset:
                return 0644;
        case hwmon_temp_crit_hyst:
                return (channel == 0) ? 0644 : 0444;
        default:
                return 0;
        }
}

static umode_t lm95245_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;
                default:
                        return 0;
                }
        case hwmon_temp:
                return lm95245_temp_is_visible(data, attr, channel);
        default:
                return 0;
        }
}

/* Return 0 if detection is successful, -ENODEV otherwise */
static int lm95245_detect(struct i2c_client *new_client,
                          struct i2c_board_info *info)
{
        struct i2c_adapter *adapter = new_client->adapter;
        int address = new_client->addr;
        const char *name;
        int rev, id;

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

        id = i2c_smbus_read_byte_data(new_client, LM95245_REG_R_MAN_ID);
        if (id != MANUFACTURER_ID)
                return -ENODEV;

        rev = i2c_smbus_read_byte_data(new_client, LM95245_REG_R_CHIP_ID);
        switch (rev) {
        case LM95235_REVISION:
                if (address != 0x18 && address != 0x29 && address != 0x4c)
                        return -ENODEV;
                name = "lm95235";
                break;
        case LM95245_REVISION:
                name = "lm95245";
                break;
        default:
                return -ENODEV;
        }

        strscpy(info->type, name, I2C_NAME_SIZE);
        return 0;
}

static int lm95245_init_client(struct lm95245_data *data)
{
        int ret;

        ret = lm95245_read_conversion_rate(data);
        if (ret < 0)
                return ret;

        return regmap_update_bits(data->regmap, LM95245_REG_RW_CONFIG1,
                                  CFG_STOP, 0);
}

static bool lm95245_is_writeable_reg(struct device *dev, unsigned int reg)
{
        switch (reg) {
        case LM95245_REG_RW_CONFIG1:
        case LM95245_REG_RW_CONVERS_RATE:
        case LM95245_REG_W_ONE_SHOT:
        case LM95245_REG_RW_CONFIG2:
        case LM95245_REG_RW_REMOTE_OFFH:
        case LM95245_REG_RW_REMOTE_OFFL:
        case LM95245_REG_RW_REMOTE_OS_LIMIT:
        case LM95245_REG_RW_LOCAL_OS_TCRIT_LIMIT:
        case LM95245_REG_RW_REMOTE_TCRIT_LIMIT:
        case LM95245_REG_RW_COMMON_HYSTERESIS:
                return true;
        default:
                return false;
        }
}

static bool lm95245_is_volatile_reg(struct device *dev, unsigned int reg)
{
        switch (reg) {
        case LM95245_REG_R_STATUS1:
        case LM95245_REG_R_STATUS2:
        case LM95245_REG_R_LOCAL_TEMPH_S:
        case LM95245_REG_R_LOCAL_TEMPL_S:
        case LM95245_REG_R_REMOTE_TEMPH_S:
        case LM95245_REG_R_REMOTE_TEMPL_S:
        case LM95245_REG_R_REMOTE_TEMPH_U:
        case LM95245_REG_R_REMOTE_TEMPL_U:
                return true;
        default:
                return false;
        }
}

static const struct regmap_config lm95245_regmap_config = {
        .reg_bits = 8,
        .val_bits = 8,
        .writeable_reg = lm95245_is_writeable_reg,
        .volatile_reg = lm95245_is_volatile_reg,
        .cache_type = REGCACHE_MAPLE,
        .use_single_read = true,
        .use_single_write = true,
};

static const struct hwmon_channel_info * const lm95245_info[] = {
        HWMON_CHANNEL_INFO(chip,
                           HWMON_C_UPDATE_INTERVAL),
        HWMON_CHANNEL_INFO(temp,
                           HWMON_T_INPUT | HWMON_T_CRIT | HWMON_T_CRIT_HYST |
                           HWMON_T_CRIT_ALARM,
                           HWMON_T_INPUT | HWMON_T_MAX | HWMON_T_MAX_HYST |
                           HWMON_T_CRIT | HWMON_T_CRIT_HYST | HWMON_T_FAULT |
                           HWMON_T_MAX_ALARM | HWMON_T_CRIT_ALARM |
                           HWMON_T_TYPE | HWMON_T_OFFSET),
        NULL
};

static const struct hwmon_ops lm95245_hwmon_ops = {
        .is_visible = lm95245_is_visible,
        .read = lm95245_read,
        .write = lm95245_write,
};

static const struct hwmon_chip_info lm95245_chip_info = {
        .ops = &lm95245_hwmon_ops,
        .info = lm95245_info,
};

static int lm95245_probe(struct i2c_client *client)
{
        struct device *dev = &client->dev;
        struct lm95245_data *data;
        struct device *hwmon_dev;
        int ret;

        data = devm_kzalloc(dev, sizeof(struct lm95245_data), GFP_KERNEL);
        if (!data)
                return -ENOMEM;

        data->regmap = devm_regmap_init_i2c(client, &lm95245_regmap_config);
        if (IS_ERR(data->regmap))
                return PTR_ERR(data->regmap);

        /* Initialize the LM95245 chip */
        ret = lm95245_init_client(data);
        if (ret < 0)
                return ret;

        hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name,
                                                         data,
                                                         &lm95245_chip_info,
                                                         NULL);
        return PTR_ERR_OR_ZERO(hwmon_dev);
}

/* Driver data (common to all clients) */
static const struct i2c_device_id lm95245_id[] = {
        { "lm95235" },
        { "lm95245" },
        { }
};
MODULE_DEVICE_TABLE(i2c, lm95245_id);

static const struct of_device_id __maybe_unused lm95245_of_match[] = {
        { .compatible = "national,lm95235" },
        { .compatible = "national,lm95245" },
        { },
};
MODULE_DEVICE_TABLE(of, lm95245_of_match);

static struct i2c_driver lm95245_driver = {
        .class          = I2C_CLASS_HWMON,
        .driver = {
                .name   = "lm95245",
                .of_match_table = of_match_ptr(lm95245_of_match),
        },
        .probe          = lm95245_probe,
        .id_table       = lm95245_id,
        .detect         = lm95245_detect,
        .address_list   = normal_i2c,
};

module_i2c_driver(lm95245_driver);

MODULE_AUTHOR("Alexander Stein <alexander.stein@systec-electronic.com>");
MODULE_DESCRIPTION("LM95235/LM95245 sensor driver");
MODULE_LICENSE("GPL");