// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Copyright (C) 2008, 2010 Davide Rizzo <elpa.rizzo@gmail.com>
 *
 * The LM95241 is a sensor chip made by National Semiconductors.
 * It reports up to three temperatures (its own plus up to two external ones).
 * Complete datasheet can be obtained from National's website at:
 *   http://www.national.com/ds.cgi/LM/LM95241.pdf
 */

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

#define DEVNAME "lm95241"

static const unsigned short normal_i2c[] = {
        0x19, 0x2a, 0x2b, I2C_CLIENT_END };

/* LM95241 registers */
#define LM95241_REG_R_MAN_ID            0xFE
#define LM95241_REG_R_CHIP_ID           0xFF
#define LM95241_REG_R_STATUS            0x02
#define LM95241_REG_RW_CONFIG           0x03
#define LM95241_REG_RW_REM_FILTER       0x06
#define LM95241_REG_RW_TRUTHERM         0x07
#define LM95241_REG_W_ONE_SHOT          0x0F
#define LM95241_REG_R_LOCAL_TEMPH       0x10
#define LM95241_REG_R_REMOTE1_TEMPH     0x11
#define LM95241_REG_R_REMOTE2_TEMPH     0x12
#define LM95241_REG_R_LOCAL_TEMPL       0x20
#define LM95241_REG_R_REMOTE1_TEMPL     0x21
#define LM95241_REG_R_REMOTE2_TEMPL     0x22
#define LM95241_REG_RW_REMOTE_MODEL     0x30

/* LM95241 specific bitfields */
#define CFG_STOP        BIT(6)
#define CFG_CR0076      0x00
#define CFG_CR0182      BIT(4)
#define CFG_CR1000      BIT(5)
#define CFG_CR2700      (BIT(4) | BIT(5))
#define CFG_CRMASK      (BIT(4) | BIT(5))
#define R1MS_MASK       BIT(0)
#define R2MS_MASK       BIT(2)
#define R1DF_MASK       BIT(1)
#define R2DF_MASK       BIT(2)
#define R1FE_MASK       BIT(0)
#define R2FE_MASK       BIT(2)
#define R1DM            BIT(0)
#define R2DM            BIT(1)
#define TT1_SHIFT       0
#define TT2_SHIFT       4
#define TT_OFF          0
#define TT_ON           1
#define TT_MASK         7
#define NATSEMI_MAN_ID  0x01
#define LM95231_CHIP_ID 0xA1
#define LM95241_CHIP_ID 0xA4

static const u8 lm95241_reg_address[] = {
        LM95241_REG_R_LOCAL_TEMPH,
        LM95241_REG_R_LOCAL_TEMPL,
        LM95241_REG_R_REMOTE1_TEMPH,
        LM95241_REG_R_REMOTE1_TEMPL,
        LM95241_REG_R_REMOTE2_TEMPH,
        LM95241_REG_R_REMOTE2_TEMPL
};

/* Client data (each client gets its own) */
struct lm95241_data {
        struct i2c_client *client;
        unsigned long last_updated;     /* in jiffies */
        unsigned long interval;         /* in milli-seconds */
        bool valid;             /* false until following fields are valid */
        /* registers values */
        u8 temp[ARRAY_SIZE(lm95241_reg_address)];
        u8 status, config, model, trutherm;
};

/* Conversions */
static int temp_from_reg_signed(u8 val_h, u8 val_l)
{
        s16 val_hl = (val_h << 8) | val_l;
        return val_hl * 1000 / 256;
}

static int temp_from_reg_unsigned(u8 val_h, u8 val_l)
{
        u16 val_hl = (val_h << 8) | val_l;
        return val_hl * 1000 / 256;
}

static struct lm95241_data *lm95241_update_device(struct device *dev)
{
        struct lm95241_data *data = dev_get_drvdata(dev);
        struct i2c_client *client = data->client;

        if (time_after(jiffies, data->last_updated
                       + msecs_to_jiffies(data->interval)) ||
            !data->valid) {
                int i;

                dev_dbg(dev, "Updating lm95241 data.\n");
                for (i = 0; i < ARRAY_SIZE(lm95241_reg_address); i++)
                        data->temp[i]
                          = i2c_smbus_read_byte_data(client,
                                                     lm95241_reg_address[i]);

                data->status = i2c_smbus_read_byte_data(client,
                                                        LM95241_REG_R_STATUS);
                data->last_updated = jiffies;
                data->valid = true;
        }
        return data;
}

static int lm95241_read_chip(struct device *dev, u32 attr, int channel,
                             long *val)
{
        struct lm95241_data *data = dev_get_drvdata(dev);

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

static int lm95241_read_temp(struct device *dev, u32 attr, int channel,
                             long *val)
{
        struct lm95241_data *data = lm95241_update_device(dev);

        switch (attr) {
        case hwmon_temp_input:
                if (!channel || (data->config & BIT(channel - 1)))
                        *val = temp_from_reg_signed(data->temp[channel * 2],
                                                data->temp[channel * 2 + 1]);
                else
                        *val = temp_from_reg_unsigned(data->temp[channel * 2],
                                                data->temp[channel * 2 + 1]);
                return 0;
        case hwmon_temp_min:
                if (channel == 1)
                        *val = (data->config & R1DF_MASK) ? -128000 : 0;
                else
                        *val = (data->config & R2DF_MASK) ? -128000 : 0;
                return 0;
        case hwmon_temp_max:
                if (channel == 1)
                        *val = (data->config & R1DF_MASK) ? 127875 : 255875;
                else
                        *val = (data->config & R2DF_MASK) ? 127875 : 255875;
                return 0;
        case hwmon_temp_type:
                if (channel == 1)
                        *val = (data->model & R1MS_MASK) ? 1 : 2;
                else
                        *val = (data->model & R2MS_MASK) ? 1 : 2;
                return 0;
        case hwmon_temp_fault:
                if (channel == 1)
                        *val = !!(data->status & R1DM);
                else
                        *val = !!(data->status & R2DM);
                return 0;
        default:
                return -EOPNOTSUPP;
        }
}

static int lm95241_read(struct device *dev, enum hwmon_sensor_types type,
                        u32 attr, int channel, long *val)
{
        switch (type) {
        case hwmon_chip:
                return lm95241_read_chip(dev, attr, channel, val);
        case hwmon_temp:
                return lm95241_read_temp(dev, attr, channel, val);
        default:
                return -EOPNOTSUPP;
        }
}

static int lm95241_write_chip(struct device *dev, u32 attr, int channel,
                              long val)
{
        struct lm95241_data *data = dev_get_drvdata(dev);
        int convrate;
        u8 config;
        int ret;

        switch (attr) {
        case hwmon_chip_update_interval:
                config = data->config & ~CFG_CRMASK;
                if (val < 130) {
                        convrate = 76;
                        config |= CFG_CR0076;
                } else if (val < 590) {
                        convrate = 182;
                        config |= CFG_CR0182;
                } else if (val < 1850) {
                        convrate = 1000;
                        config |= CFG_CR1000;
                } else {
                        convrate = 2700;
                        config |= CFG_CR2700;
                }
                data->interval = convrate;
                data->config = config;
                ret = i2c_smbus_write_byte_data(data->client,
                                                LM95241_REG_RW_CONFIG, config);
                break;
        default:
                ret = -EOPNOTSUPP;
                break;
        }
        return ret;
}

static int lm95241_write_temp(struct device *dev, u32 attr, int channel,
                              long val)
{
        struct lm95241_data *data = dev_get_drvdata(dev);
        struct i2c_client *client = data->client;
        int ret;

        switch (attr) {
        case hwmon_temp_min:
                if (channel == 1) {
                        if (val < 0)
                                data->config |= R1DF_MASK;
                        else
                                data->config &= ~R1DF_MASK;
                } else {
                        if (val < 0)
                                data->config |= R2DF_MASK;
                        else
                                data->config &= ~R2DF_MASK;
                }
                data->valid = false;
                ret = i2c_smbus_write_byte_data(client, LM95241_REG_RW_CONFIG,
                                                data->config);
                break;
        case hwmon_temp_max:
                if (channel == 1) {
                        if (val <= 127875)
                                data->config |= R1DF_MASK;
                        else
                                data->config &= ~R1DF_MASK;
                } else {
                        if (val <= 127875)
                                data->config |= R2DF_MASK;
                        else
                                data->config &= ~R2DF_MASK;
                }
                data->valid = false;
                ret = i2c_smbus_write_byte_data(client, LM95241_REG_RW_CONFIG,
                                                data->config);
                break;
        case hwmon_temp_type:
                if (val != 1 && val != 2) {
                        ret = -EINVAL;
                        break;
                }
                if (channel == 1) {
                        data->trutherm &= ~(TT_MASK << TT1_SHIFT);
                        if (val == 1) {
                                data->model |= R1MS_MASK;
                                data->trutherm |= (TT_ON << TT1_SHIFT);
                        } else {
                                data->model &= ~R1MS_MASK;
                                data->trutherm |= (TT_OFF << TT1_SHIFT);
                        }
                } else {
                        data->trutherm &= ~(TT_MASK << TT2_SHIFT);
                        if (val == 1) {
                                data->model |= R2MS_MASK;
                                data->trutherm |= (TT_ON << TT2_SHIFT);
                        } else {
                                data->model &= ~R2MS_MASK;
                                data->trutherm |= (TT_OFF << TT2_SHIFT);
                        }
                }
                ret = i2c_smbus_write_byte_data(client,
                                                LM95241_REG_RW_REMOTE_MODEL,
                                                data->model);
                if (ret < 0)
                        break;
                ret = i2c_smbus_write_byte_data(client, LM95241_REG_RW_TRUTHERM,
                                                data->trutherm);
                break;
        default:
                ret = -EOPNOTSUPP;
                break;
        }
        return ret;
}

static int lm95241_write(struct device *dev, enum hwmon_sensor_types type,
                         u32 attr, int channel, long val)
{
        switch (type) {
        case hwmon_chip:
                return lm95241_write_chip(dev, attr, channel, val);
        case hwmon_temp:
                return lm95241_write_temp(dev, attr, channel, val);
        default:
                return -EOPNOTSUPP;
        }
}

static umode_t lm95241_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;
                }
                break;
        case hwmon_temp:
                switch (attr) {
                case hwmon_temp_input:
                        return 0444;
                case hwmon_temp_fault:
                        return 0444;
                case hwmon_temp_min:
                case hwmon_temp_max:
                case hwmon_temp_type:
                        return 0644;
                }
                break;
        default:
                break;
        }
        return 0;
}

/* Return 0 if detection is successful, -ENODEV otherwise */
static int lm95241_detect(struct i2c_client *new_client,
                          struct i2c_board_info *info)
{
        struct i2c_adapter *adapter = new_client->adapter;
        const char *name;
        int mfg_id, chip_id;

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

        mfg_id = i2c_smbus_read_byte_data(new_client, LM95241_REG_R_MAN_ID);
        if (mfg_id != NATSEMI_MAN_ID)
                return -ENODEV;

        chip_id = i2c_smbus_read_byte_data(new_client, LM95241_REG_R_CHIP_ID);
        switch (chip_id) {
        case LM95231_CHIP_ID:
                name = "lm95231";
                break;
        case LM95241_CHIP_ID:
                name = "lm95241";
                break;
        default:
                return -ENODEV;
        }

        /* Fill the i2c board info */
        strscpy(info->type, name, I2C_NAME_SIZE);
        return 0;
}

static void lm95241_init_client(struct i2c_client *client,
                                struct lm95241_data *data)
{
        data->interval = 1000;
        data->config = CFG_CR1000;
        data->trutherm = (TT_OFF << TT1_SHIFT) | (TT_OFF << TT2_SHIFT);

        i2c_smbus_write_byte_data(client, LM95241_REG_RW_CONFIG, data->config);
        i2c_smbus_write_byte_data(client, LM95241_REG_RW_REM_FILTER,
                                  R1FE_MASK | R2FE_MASK);
        i2c_smbus_write_byte_data(client, LM95241_REG_RW_TRUTHERM,
                                  data->trutherm);
        i2c_smbus_write_byte_data(client, LM95241_REG_RW_REMOTE_MODEL,
                                  data->model);
}

static const struct hwmon_channel_info * const lm95241_info[] = {
        HWMON_CHANNEL_INFO(chip,
                           HWMON_C_UPDATE_INTERVAL),
        HWMON_CHANNEL_INFO(temp,
                           HWMON_T_INPUT,
                           HWMON_T_INPUT | HWMON_T_MAX | HWMON_T_MIN |
                           HWMON_T_TYPE | HWMON_T_FAULT,
                           HWMON_T_INPUT | HWMON_T_MAX | HWMON_T_MIN |
                           HWMON_T_TYPE | HWMON_T_FAULT),
        NULL
};

static const struct hwmon_ops lm95241_hwmon_ops = {
        .is_visible = lm95241_is_visible,
        .read = lm95241_read,
        .write = lm95241_write,
};

static const struct hwmon_chip_info lm95241_chip_info = {
        .ops = &lm95241_hwmon_ops,
        .info = lm95241_info,
};

static int lm95241_probe(struct i2c_client *client)
{
        struct device *dev = &client->dev;
        struct lm95241_data *data;
        struct device *hwmon_dev;

        data = devm_kzalloc(dev, sizeof(struct lm95241_data), GFP_KERNEL);
        if (!data)
                return -ENOMEM;

        data->client = client;

        /* Initialize the LM95241 chip */
        lm95241_init_client(client, data);

        hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name,
                                                           data,
                                                           &lm95241_chip_info,
                                                           NULL);
        return PTR_ERR_OR_ZERO(hwmon_dev);
}

/* Driver data (common to all clients) */
static const struct i2c_device_id lm95241_id[] = {
        { "lm95231" },
        { "lm95241" },
        { }
};
MODULE_DEVICE_TABLE(i2c, lm95241_id);

static struct i2c_driver lm95241_driver = {
        .class          = I2C_CLASS_HWMON,
        .driver = {
                .name   = DEVNAME,
        },
        .probe          = lm95241_probe,
        .id_table       = lm95241_id,
        .detect         = lm95241_detect,
        .address_list   = normal_i2c,
};

module_i2c_driver(lm95241_driver);

MODULE_AUTHOR("Davide Rizzo <elpa.rizzo@gmail.com>");
MODULE_DESCRIPTION("LM95231/LM95241 sensor driver");
MODULE_LICENSE("GPL");