/*
 * lm75.c - Part of lm_sensors, Linux kernel modules for hardware
 *       monitoring
 * Copyright (c) 1998, 1999  Frodo Looijaard <frodol@dds.nl>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/jiffies.h>
#include <linux/i2c.h>
#include <linux/hwmon.h>
#include <linux/hwmon-sysfs.h>
#include <linux/err.h>
#include <linux/of_device.h>
#include <linux/of.h>
#include <linux/regmap.h>
#include "lm75.h"


/*
 * This driver handles the LM75 and compatible digital temperature sensors.
 */

enum lm75_type {                /* keep sorted in alphabetical order */
        adt75,
        ds1775,
        ds75,
        ds7505,
        g751,
        lm75,
        lm75a,
        lm75b,
        max6625,
        max6626,
        mcp980x,
        stds75,
        tcn75,
        tmp100,
        tmp101,
        tmp105,
        tmp112,
        tmp175,
        tmp275,
        tmp75,
        tmp75c,
};

/* Addresses scanned */
static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b, 0x4c,
                                        0x4d, 0x4e, 0x4f, I2C_CLIENT_END };


/* The LM75 registers */
#define LM75_REG_TEMP           0x00
#define LM75_REG_CONF           0x01
#define LM75_REG_HYST           0x02
#define LM75_REG_MAX            0x03

/* Each client has this additional data */
struct lm75_data {
        struct i2c_client       *client;
        struct regmap           *regmap;
        u8                      orig_conf;
        u8                      resolution;     /* In bits, between 9 and 12 */
        u8                      resolution_limits;
        unsigned int            sample_time;    /* In ms */
};

/*-----------------------------------------------------------------------*/

static inline long lm75_reg_to_mc(s16 temp, u8 resolution)
{
        return ((temp >> (16 - resolution)) * 1000) >> (resolution - 8);
}

static int lm75_read(struct device *dev, enum hwmon_sensor_types type,
                     u32 attr, int channel, long *val)
{
        struct lm75_data *data = dev_get_drvdata(dev);
        unsigned int regval;
        int err, reg;

        switch (type) {
        case hwmon_chip:
                switch (attr) {
                case hwmon_chip_update_interval:
                        *val = data->sample_time;
                        break;
                default:
                        return -EINVAL;
                }
                break;
        case hwmon_temp:
                switch (attr) {
                case hwmon_temp_input:
                        reg = LM75_REG_TEMP;
                        break;
                case hwmon_temp_max:
                        reg = LM75_REG_MAX;
                        break;
                case hwmon_temp_max_hyst:
                        reg = LM75_REG_HYST;
                        break;
                default:
                        return -EINVAL;
                }
                err = regmap_read(data->regmap, reg, &regval);
                if (err < 0)
                        return err;

                *val = lm75_reg_to_mc(regval, data->resolution);
                break;
        default:
                return -EINVAL;
        }
        return 0;
}

static int lm75_write(struct device *dev, enum hwmon_sensor_types type,
                      u32 attr, int channel, long temp)
{
        struct lm75_data *data = dev_get_drvdata(dev);
        u8 resolution;
        int reg;

        if (type != hwmon_temp)
                return -EINVAL;

        switch (attr) {
        case hwmon_temp_max:
                reg = LM75_REG_MAX;
                break;
        case hwmon_temp_max_hyst:
                reg = LM75_REG_HYST;
                break;
        default:
                return -EINVAL;
        }

        /*
         * Resolution of limit registers is assumed to be the same as the
         * temperature input register resolution unless given explicitly.
         */
        if (data->resolution_limits)
                resolution = data->resolution_limits;
        else
                resolution = data->resolution;

        temp = clamp_val(temp, LM75_TEMP_MIN, LM75_TEMP_MAX);
        temp = DIV_ROUND_CLOSEST(temp  << (resolution - 8),
                                 1000) << (16 - resolution);

        return regmap_write(data->regmap, reg, temp);
}

static umode_t lm75_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 S_IRUGO;
                }
                break;
        case hwmon_temp:
                switch (attr) {
                case hwmon_temp_input:
                        return S_IRUGO;
                case hwmon_temp_max:
                case hwmon_temp_max_hyst:
                        return S_IRUGO | S_IWUSR;
                }
                break;
        default:
                break;
        }
        return 0;
}

/*-----------------------------------------------------------------------*/

/* device probe and removal */

/* chip configuration */

static const u32 lm75_chip_config[] = {
        HWMON_C_REGISTER_TZ | HWMON_C_UPDATE_INTERVAL,
        0
};

static const struct hwmon_channel_info lm75_chip = {
        .type = hwmon_chip,
        .config = lm75_chip_config,
};

static const u32 lm75_temp_config[] = {
        HWMON_T_INPUT | HWMON_T_MAX | HWMON_T_MAX_HYST,
        0
};

static const struct hwmon_channel_info lm75_temp = {
        .type = hwmon_temp,
        .config = lm75_temp_config,
};

static const struct hwmon_channel_info *lm75_info[] = {
        &lm75_chip,
        &lm75_temp,
        NULL
};

static const struct hwmon_ops lm75_hwmon_ops = {
        .is_visible = lm75_is_visible,
        .read = lm75_read,
        .write = lm75_write,
};

static const struct hwmon_chip_info lm75_chip_info = {
        .ops = &lm75_hwmon_ops,
        .info = lm75_info,
};

static bool lm75_is_writeable_reg(struct device *dev, unsigned int reg)
{
        return reg != LM75_REG_TEMP;
}

static bool lm75_is_volatile_reg(struct device *dev, unsigned int reg)
{
        return reg == LM75_REG_TEMP;
}

static const struct regmap_config lm75_regmap_config = {
        .reg_bits = 8,
        .val_bits = 16,
        .max_register = LM75_REG_MAX,
        .writeable_reg = lm75_is_writeable_reg,
        .volatile_reg = lm75_is_volatile_reg,
        .val_format_endian = REGMAP_ENDIAN_BIG,
        .cache_type = REGCACHE_RBTREE,
        .use_single_read = true,
        .use_single_write = true,
};

static void lm75_remove(void *data)
{
        struct lm75_data *lm75 = data;
        struct i2c_client *client = lm75->client;

        i2c_smbus_write_byte_data(client, LM75_REG_CONF, lm75->orig_conf);
}

static int
lm75_probe(struct i2c_client *client, const struct i2c_device_id *id)
{
        struct device *dev = &client->dev;
        struct device *hwmon_dev;
        struct lm75_data *data;
        int status, err;
        u8 set_mask, clr_mask;
        int new;
        enum lm75_type kind;

        if (client->dev.of_node)
                kind = (enum lm75_type)of_device_get_match_data(&client->dev);
        else
                kind = id->driver_data;

        if (!i2c_check_functionality(client->adapter,
                        I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA))
                return -EIO;

        data = devm_kzalloc(dev, sizeof(struct lm75_data), GFP_KERNEL);
        if (!data)
                return -ENOMEM;

        data->client = client;

        data->regmap = devm_regmap_init_i2c(client, &lm75_regmap_config);
        if (IS_ERR(data->regmap))
                return PTR_ERR(data->regmap);

        /* Set to LM75 resolution (9 bits, 1/2 degree C) and range.
         * Then tweak to be more precise when appropriate.
         */
        set_mask = 0;
        clr_mask = LM75_SHUTDOWN;               /* continuous conversions */

        switch (kind) {
        case adt75:
                clr_mask |= 1 << 5;             /* not one-shot mode */
                data->resolution = 12;
                data->sample_time = MSEC_PER_SEC / 8;
                break;
        case ds1775:
        case ds75:
        case stds75:
                clr_mask |= 3 << 5;
                set_mask |= 2 << 5;             /* 11-bit mode */
                data->resolution = 11;
                data->sample_time = MSEC_PER_SEC;
                break;
        case ds7505:
                set_mask |= 3 << 5;             /* 12-bit mode */
                data->resolution = 12;
                data->sample_time = MSEC_PER_SEC / 4;
                break;
        case g751:
        case lm75:
        case lm75a:
                data->resolution = 9;
                data->sample_time = MSEC_PER_SEC / 2;
                break;
        case lm75b:
                data->resolution = 11;
                data->sample_time = MSEC_PER_SEC / 4;
                break;
        case max6625:
                data->resolution = 9;
                data->sample_time = MSEC_PER_SEC / 4;
                break;
        case max6626:
                data->resolution = 12;
                data->resolution_limits = 9;
                data->sample_time = MSEC_PER_SEC / 4;
                break;
        case tcn75:
                data->resolution = 9;
                data->sample_time = MSEC_PER_SEC / 8;
                break;
        case mcp980x:
                data->resolution_limits = 9;
                /* fall through */
        case tmp100:
        case tmp101:
                set_mask |= 3 << 5;             /* 12-bit mode */
                data->resolution = 12;
                data->sample_time = MSEC_PER_SEC;
                clr_mask |= 1 << 7;             /* not one-shot mode */
                break;
        case tmp112:
                set_mask |= 3 << 5;             /* 12-bit mode */
                clr_mask |= 1 << 7;             /* not one-shot mode */
                data->resolution = 12;
                data->sample_time = MSEC_PER_SEC / 4;
                break;
        case tmp105:
        case tmp175:
        case tmp275:
        case tmp75:
                set_mask |= 3 << 5;             /* 12-bit mode */
                clr_mask |= 1 << 7;             /* not one-shot mode */
                data->resolution = 12;
                data->sample_time = MSEC_PER_SEC / 2;
                break;
        case tmp75c:
                clr_mask |= 1 << 5;             /* not one-shot mode */
                data->resolution = 12;
                data->sample_time = MSEC_PER_SEC / 4;
                break;
        }

        /* configure as specified */
        status = i2c_smbus_read_byte_data(client, LM75_REG_CONF);
        if (status < 0) {
                dev_dbg(dev, "Can't read config? %d\n", status);
                return status;
        }
        data->orig_conf = status;
        new = status & ~clr_mask;
        new |= set_mask;
        if (status != new)
                i2c_smbus_write_byte_data(client, LM75_REG_CONF, new);

        err = devm_add_action_or_reset(dev, lm75_remove, data);
        if (err)
                return err;

        dev_dbg(dev, "Config %02x\n", new);

        hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name,
                                                         data, &lm75_chip_info,
                                                         NULL);
        if (IS_ERR(hwmon_dev))
                return PTR_ERR(hwmon_dev);

        dev_info(dev, "%s: sensor '%s'\n", dev_name(hwmon_dev), client->name);

        return 0;
}

static const struct i2c_device_id lm75_ids[] = {
        { "adt75", adt75, },
        { "ds1775", ds1775, },
        { "ds75", ds75, },
        { "ds7505", ds7505, },
        { "g751", g751, },
        { "lm75", lm75, },
        { "lm75a", lm75a, },
        { "lm75b", lm75b, },
        { "max6625", max6625, },
        { "max6626", max6626, },
        { "mcp980x", mcp980x, },
        { "stds75", stds75, },
        { "tcn75", tcn75, },
        { "tmp100", tmp100, },
        { "tmp101", tmp101, },
        { "tmp105", tmp105, },
        { "tmp112", tmp112, },
        { "tmp175", tmp175, },
        { "tmp275", tmp275, },
        { "tmp75", tmp75, },
        { "tmp75c", tmp75c, },
        { /* LIST END */ }
};
MODULE_DEVICE_TABLE(i2c, lm75_ids);

static const struct of_device_id lm75_of_match[] = {
        {
                .compatible = "adi,adt75",
                .data = (void *)adt75
        },
        {
                .compatible = "dallas,ds1775",
                .data = (void *)ds1775
        },
        {
                .compatible = "dallas,ds75",
                .data = (void *)ds75
        },
        {
                .compatible = "dallas,ds7505",
                .data = (void *)ds7505
        },
        {
                .compatible = "gmt,g751",
                .data = (void *)g751
        },
        {
                .compatible = "national,lm75",
                .data = (void *)lm75
        },
        {
                .compatible = "national,lm75a",
                .data = (void *)lm75a
        },
        {
                .compatible = "national,lm75b",
                .data = (void *)lm75b
        },
        {
                .compatible = "maxim,max6625",
                .data = (void *)max6625
        },
        {
                .compatible = "maxim,max6626",
                .data = (void *)max6626
        },
        {
                .compatible = "maxim,mcp980x",
                .data = (void *)mcp980x
        },
        {
                .compatible = "st,stds75",
                .data = (void *)stds75
        },
        {
                .compatible = "microchip,tcn75",
                .data = (void *)tcn75
        },
        {
                .compatible = "ti,tmp100",
                .data = (void *)tmp100
        },
        {
                .compatible = "ti,tmp101",
                .data = (void *)tmp101
        },
        {
                .compatible = "ti,tmp105",
                .data = (void *)tmp105
        },
        {
                .compatible = "ti,tmp112",
                .data = (void *)tmp112
        },
        {
                .compatible = "ti,tmp175",
                .data = (void *)tmp175
        },
        {
                .compatible = "ti,tmp275",
                .data = (void *)tmp275
        },
        {
                .compatible = "ti,tmp75",
                .data = (void *)tmp75
        },
        {
                .compatible = "ti,tmp75c",
                .data = (void *)tmp75c
        },
        { },
};
MODULE_DEVICE_TABLE(of, lm75_of_match);

#define LM75A_ID 0xA1

/* Return 0 if detection is successful, -ENODEV otherwise */
static int lm75_detect(struct i2c_client *new_client,
                       struct i2c_board_info *info)
{
        struct i2c_adapter *adapter = new_client->adapter;
        int i;
        int conf, hyst, os;
        bool is_lm75a = 0;

        if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA |
                                     I2C_FUNC_SMBUS_WORD_DATA))
                return -ENODEV;

        /*
         * Now, we do the remaining detection. There is no identification-
         * dedicated register so we have to rely on several tricks:
         * unused bits, registers cycling over 8-address boundaries,
         * addresses 0x04-0x07 returning the last read value.
         * The cycling+unused addresses combination is not tested,
         * since it would significantly slow the detection down and would
         * hardly add any value.
         *
         * The National Semiconductor LM75A is different than earlier
         * LM75s.  It has an ID byte of 0xaX (where X is the chip
         * revision, with 1 being the only revision in existence) in
         * register 7, and unused registers return 0xff rather than the
         * last read value.
         *
         * Note that this function only detects the original National
         * Semiconductor LM75 and the LM75A. Clones from other vendors
         * aren't detected, on purpose, because they are typically never
         * found on PC hardware. They are found on embedded designs where
         * they can be instantiated explicitly so detection is not needed.
         * The absence of identification registers on all these clones
         * would make their exhaustive detection very difficult and weak,
         * and odds are that the driver would bind to unsupported devices.
         */

        /* Unused bits */
        conf = i2c_smbus_read_byte_data(new_client, 1);
        if (conf & 0xe0)
                return -ENODEV;

        /* First check for LM75A */
        if (i2c_smbus_read_byte_data(new_client, 7) == LM75A_ID) {
                /* LM75A returns 0xff on unused registers so
                   just to be sure we check for that too. */
                if (i2c_smbus_read_byte_data(new_client, 4) != 0xff
                 || i2c_smbus_read_byte_data(new_client, 5) != 0xff
                 || i2c_smbus_read_byte_data(new_client, 6) != 0xff)
                        return -ENODEV;
                is_lm75a = 1;
                hyst = i2c_smbus_read_byte_data(new_client, 2);
                os = i2c_smbus_read_byte_data(new_client, 3);
        } else { /* Traditional style LM75 detection */
                /* Unused addresses */
                hyst = i2c_smbus_read_byte_data(new_client, 2);
                if (i2c_smbus_read_byte_data(new_client, 4) != hyst
                 || i2c_smbus_read_byte_data(new_client, 5) != hyst
                 || i2c_smbus_read_byte_data(new_client, 6) != hyst
                 || i2c_smbus_read_byte_data(new_client, 7) != hyst)
                        return -ENODEV;
                os = i2c_smbus_read_byte_data(new_client, 3);
                if (i2c_smbus_read_byte_data(new_client, 4) != os
                 || i2c_smbus_read_byte_data(new_client, 5) != os
                 || i2c_smbus_read_byte_data(new_client, 6) != os
                 || i2c_smbus_read_byte_data(new_client, 7) != os)
                        return -ENODEV;
        }
        /*
         * It is very unlikely that this is a LM75 if both
         * hysteresis and temperature limit registers are 0.
         */
        if (hyst == 0 && os == 0)
                return -ENODEV;

        /* Addresses cycling */
        for (i = 8; i <= 248; i += 40) {
                if (i2c_smbus_read_byte_data(new_client, i + 1) != conf
                 || i2c_smbus_read_byte_data(new_client, i + 2) != hyst
                 || i2c_smbus_read_byte_data(new_client, i + 3) != os)
                        return -ENODEV;
                if (is_lm75a && i2c_smbus_read_byte_data(new_client, i + 7)
                                != LM75A_ID)
                        return -ENODEV;
        }

        strlcpy(info->type, is_lm75a ? "lm75a" : "lm75", I2C_NAME_SIZE);

        return 0;
}

#ifdef CONFIG_PM
static int lm75_suspend(struct device *dev)
{
        int status;
        struct i2c_client *client = to_i2c_client(dev);
        status = i2c_smbus_read_byte_data(client, LM75_REG_CONF);
        if (status < 0) {
                dev_dbg(&client->dev, "Can't read config? %d\n", status);
                return status;
        }
        status = status | LM75_SHUTDOWN;
        i2c_smbus_write_byte_data(client, LM75_REG_CONF, status);
        return 0;
}

static int lm75_resume(struct device *dev)
{
        int status;
        struct i2c_client *client = to_i2c_client(dev);
        status = i2c_smbus_read_byte_data(client, LM75_REG_CONF);
        if (status < 0) {
                dev_dbg(&client->dev, "Can't read config? %d\n", status);
                return status;
        }
        status = status & ~LM75_SHUTDOWN;
        i2c_smbus_write_byte_data(client, LM75_REG_CONF, status);
        return 0;
}

static const struct dev_pm_ops lm75_dev_pm_ops = {
        .suspend        = lm75_suspend,
        .resume         = lm75_resume,
};
#define LM75_DEV_PM_OPS (&lm75_dev_pm_ops)
#else
#define LM75_DEV_PM_OPS NULL
#endif /* CONFIG_PM */

static struct i2c_driver lm75_driver = {
        .class          = I2C_CLASS_HWMON,
        .driver = {
                .name   = "lm75",
                .of_match_table = of_match_ptr(lm75_of_match),
                .pm     = LM75_DEV_PM_OPS,
        },
        .probe          = lm75_probe,
        .id_table       = lm75_ids,
        .detect         = lm75_detect,
        .address_list   = normal_i2c,
};

module_i2c_driver(lm75_driver);

MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl>");
MODULE_DESCRIPTION("LM75 driver");
MODULE_LICENSE("GPL");