/*
 * adm1021.c - Part of lm_sensors, Linux kernel modules for hardware
 *             monitoring
 * Copyright (c) 1998, 1999  Frodo Looijaard <frodol@dds.nl> and
 *                           Philip Edelbrock <phil@netroedge.com>
 *
 * 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/mutex.h>


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

enum chips {
        adm1021, adm1023, max1617, max1617a, thmc10, lm84, gl523sm, mc1066 };

/* adm1021 constants specified below */

/* The adm1021 registers */
/* Read-only */
/* For nr in 0-1 */
#define ADM1021_REG_TEMP(nr)            (nr)
#define ADM1021_REG_STATUS              0x02
/* 0x41 = AD, 0x49 = TI, 0x4D = Maxim, 0x23 = Genesys , 0x54 = Onsemi */
#define ADM1021_REG_MAN_ID              0xFE
/* ADM1021 = 0x0X, ADM1023 = 0x3X */
#define ADM1021_REG_DEV_ID              0xFF
/* These use different addresses for reading/writing */
#define ADM1021_REG_CONFIG_R            0x03
#define ADM1021_REG_CONFIG_W            0x09
#define ADM1021_REG_CONV_RATE_R         0x04
#define ADM1021_REG_CONV_RATE_W         0x0A
/* These are for the ADM1023's additional precision on the remote temp sensor */
#define ADM1023_REG_REM_TEMP_PREC       0x10
#define ADM1023_REG_REM_OFFSET          0x11
#define ADM1023_REG_REM_OFFSET_PREC     0x12
#define ADM1023_REG_REM_TOS_PREC        0x13
#define ADM1023_REG_REM_THYST_PREC      0x14
/* limits */
/* For nr in 0-1 */
#define ADM1021_REG_TOS_R(nr)           (0x05 + 2 * (nr))
#define ADM1021_REG_TOS_W(nr)           (0x0B + 2 * (nr))
#define ADM1021_REG_THYST_R(nr)         (0x06 + 2 * (nr))
#define ADM1021_REG_THYST_W(nr)         (0x0C + 2 * (nr))
/* write-only */
#define ADM1021_REG_ONESHOT             0x0F

/* Initial values */

/*
 * Note: Even though I left the low and high limits named os and hyst,
 * they don't quite work like a thermostat the way the LM75 does.  I.e.,
 * a lower temp than THYST actually triggers an alarm instead of
 * clearing it.  Weird, ey?   --Phil
 */

/* Each client has this additional data */
struct adm1021_data {
        struct i2c_client *client;
        enum chips type;

        const struct attribute_group *groups[3];

        struct mutex update_lock;
        char valid;             /* !=0 if following fields are valid */
        char low_power;         /* !=0 if device in low power mode */
        unsigned long last_updated;     /* In jiffies */

        int temp_max[2];                /* Register values */
        int temp_min[2];
        int temp[2];
        u8 alarms;
        /* Special values for ADM1023 only */
        u8 remote_temp_offset;
        u8 remote_temp_offset_prec;
};

/* (amalysh) read only mode, otherwise any limit's writing confuse BIOS */
static bool read_only;

static struct adm1021_data *adm1021_update_device(struct device *dev)
{
        struct adm1021_data *data = dev_get_drvdata(dev);
        struct i2c_client *client = data->client;

        mutex_lock(&data->update_lock);

        if (time_after(jiffies, data->last_updated + HZ + HZ / 2)
            || !data->valid) {
                int i;

                dev_dbg(dev, "Starting adm1021 update\n");

                for (i = 0; i < 2; i++) {
                        data->temp[i] = 1000 *
                                (s8) i2c_smbus_read_byte_data(
                                        client, ADM1021_REG_TEMP(i));
                        data->temp_max[i] = 1000 *
                                (s8) i2c_smbus_read_byte_data(
                                        client, ADM1021_REG_TOS_R(i));
                        if (data->type != lm84) {
                                data->temp_min[i] = 1000 *
                                  (s8) i2c_smbus_read_byte_data(client,
                                                        ADM1021_REG_THYST_R(i));
                        }
                }
                data->alarms = i2c_smbus_read_byte_data(client,
                                                ADM1021_REG_STATUS) & 0x7c;
                if (data->type == adm1023) {
                        /*
                         * The ADM1023 provides 3 extra bits of precision for
                         * the remote sensor in extra registers.
                         */
                        data->temp[1] += 125 * (i2c_smbus_read_byte_data(
                                client, ADM1023_REG_REM_TEMP_PREC) >> 5);
                        data->temp_max[1] += 125 * (i2c_smbus_read_byte_data(
                                client, ADM1023_REG_REM_TOS_PREC) >> 5);
                        data->temp_min[1] += 125 * (i2c_smbus_read_byte_data(
                                client, ADM1023_REG_REM_THYST_PREC) >> 5);
                        data->remote_temp_offset =
                                i2c_smbus_read_byte_data(client,
                                                ADM1023_REG_REM_OFFSET);
                        data->remote_temp_offset_prec =
                                i2c_smbus_read_byte_data(client,
                                                ADM1023_REG_REM_OFFSET_PREC);
                }
                data->last_updated = jiffies;
                data->valid = 1;
        }

        mutex_unlock(&data->update_lock);

        return data;
}

static ssize_t show_temp(struct device *dev,
                         struct device_attribute *devattr, char *buf)
{
        int index = to_sensor_dev_attr(devattr)->index;
        struct adm1021_data *data = adm1021_update_device(dev);

        return sprintf(buf, "%d\n", data->temp[index]);
}

static ssize_t show_temp_max(struct device *dev,
                             struct device_attribute *devattr, char *buf)
{
        int index = to_sensor_dev_attr(devattr)->index;
        struct adm1021_data *data = adm1021_update_device(dev);

        return sprintf(buf, "%d\n", data->temp_max[index]);
}

static ssize_t show_temp_min(struct device *dev,
                             struct device_attribute *devattr, char *buf)
{
        int index = to_sensor_dev_attr(devattr)->index;
        struct adm1021_data *data = adm1021_update_device(dev);

        return sprintf(buf, "%d\n", data->temp_min[index]);
}

static ssize_t show_alarm(struct device *dev, struct device_attribute *attr,
                          char *buf)
{
        int index = to_sensor_dev_attr(attr)->index;
        struct adm1021_data *data = adm1021_update_device(dev);
        return sprintf(buf, "%u\n", (data->alarms >> index) & 1);
}

static ssize_t show_alarms(struct device *dev,
                           struct device_attribute *attr,
                           char *buf)
{
        struct adm1021_data *data = adm1021_update_device(dev);
        return sprintf(buf, "%u\n", data->alarms);
}

static ssize_t set_temp_max(struct device *dev,
                            struct device_attribute *devattr,
                            const char *buf, size_t count)
{
        int index = to_sensor_dev_attr(devattr)->index;
        struct adm1021_data *data = dev_get_drvdata(dev);
        struct i2c_client *client = data->client;
        long temp;
        int reg_val, err;

        err = kstrtol(buf, 10, &temp);
        if (err)
                return err;
        temp /= 1000;

        mutex_lock(&data->update_lock);
        reg_val = clamp_val(temp, -128, 127);
        data->temp_max[index] = reg_val * 1000;
        if (!read_only)
                i2c_smbus_write_byte_data(client, ADM1021_REG_TOS_W(index),
                                          reg_val);
        mutex_unlock(&data->update_lock);

        return count;
}

static ssize_t set_temp_min(struct device *dev,
                            struct device_attribute *devattr,
                            const char *buf, size_t count)
{
        int index = to_sensor_dev_attr(devattr)->index;
        struct adm1021_data *data = dev_get_drvdata(dev);
        struct i2c_client *client = data->client;
        long temp;
        int reg_val, err;

        err = kstrtol(buf, 10, &temp);
        if (err)
                return err;
        temp /= 1000;

        mutex_lock(&data->update_lock);
        reg_val = clamp_val(temp, -128, 127);
        data->temp_min[index] = reg_val * 1000;
        if (!read_only)
                i2c_smbus_write_byte_data(client, ADM1021_REG_THYST_W(index),
                                          reg_val);
        mutex_unlock(&data->update_lock);

        return count;
}

static ssize_t show_low_power(struct device *dev,
                              struct device_attribute *devattr, char *buf)
{
        struct adm1021_data *data = adm1021_update_device(dev);
        return sprintf(buf, "%d\n", data->low_power);
}

static ssize_t set_low_power(struct device *dev,
                             struct device_attribute *devattr,
                             const char *buf, size_t count)
{
        struct adm1021_data *data = dev_get_drvdata(dev);
        struct i2c_client *client = data->client;
        char low_power;
        unsigned long val;
        int err;

        err = kstrtoul(buf, 10, &val);
        if (err)
                return err;
        low_power = val != 0;

        mutex_lock(&data->update_lock);
        if (low_power != data->low_power) {
                int config = i2c_smbus_read_byte_data(
                        client, ADM1021_REG_CONFIG_R);
                data->low_power = low_power;
                i2c_smbus_write_byte_data(client, ADM1021_REG_CONFIG_W,
                        (config & 0xBF) | (low_power << 6));
        }
        mutex_unlock(&data->update_lock);

        return count;
}


static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp, NULL, 0);
static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO, show_temp_max,
                          set_temp_max, 0);
static SENSOR_DEVICE_ATTR(temp1_min, S_IWUSR | S_IRUGO, show_temp_min,
                          set_temp_min, 0);
static SENSOR_DEVICE_ATTR(temp2_input, S_IRUGO, show_temp, NULL, 1);
static SENSOR_DEVICE_ATTR(temp2_max, S_IWUSR | S_IRUGO, show_temp_max,
                          set_temp_max, 1);
static SENSOR_DEVICE_ATTR(temp2_min, S_IWUSR | S_IRUGO, show_temp_min,
                          set_temp_min, 1);
static SENSOR_DEVICE_ATTR(temp1_max_alarm, S_IRUGO, show_alarm, NULL, 6);
static SENSOR_DEVICE_ATTR(temp1_min_alarm, S_IRUGO, show_alarm, NULL, 5);
static SENSOR_DEVICE_ATTR(temp2_max_alarm, S_IRUGO, show_alarm, NULL, 4);
static SENSOR_DEVICE_ATTR(temp2_min_alarm, S_IRUGO, show_alarm, NULL, 3);
static SENSOR_DEVICE_ATTR(temp2_fault, S_IRUGO, show_alarm, NULL, 2);

static DEVICE_ATTR(alarms, S_IRUGO, show_alarms, NULL);
static DEVICE_ATTR(low_power, S_IWUSR | S_IRUGO, show_low_power, set_low_power);

static struct attribute *adm1021_attributes[] = {
        &sensor_dev_attr_temp1_max.dev_attr.attr,
        &sensor_dev_attr_temp1_input.dev_attr.attr,
        &sensor_dev_attr_temp2_max.dev_attr.attr,
        &sensor_dev_attr_temp2_input.dev_attr.attr,
        &sensor_dev_attr_temp1_max_alarm.dev_attr.attr,
        &sensor_dev_attr_temp2_max_alarm.dev_attr.attr,
        &sensor_dev_attr_temp2_fault.dev_attr.attr,
        &dev_attr_alarms.attr,
        &dev_attr_low_power.attr,
        NULL
};

static const struct attribute_group adm1021_group = {
        .attrs = adm1021_attributes,
};

static struct attribute *adm1021_min_attributes[] = {
        &sensor_dev_attr_temp1_min.dev_attr.attr,
        &sensor_dev_attr_temp2_min.dev_attr.attr,
        &sensor_dev_attr_temp1_min_alarm.dev_attr.attr,
        &sensor_dev_attr_temp2_min_alarm.dev_attr.attr,
        NULL
};

static const struct attribute_group adm1021_min_group = {
        .attrs = adm1021_min_attributes,
};

/* Return 0 if detection is successful, -ENODEV otherwise */
static int adm1021_detect(struct i2c_client *client,
                          struct i2c_board_info *info)
{
        struct i2c_adapter *adapter = client->adapter;
        const char *type_name;
        int conv_rate, status, config, man_id, dev_id;

        if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA)) {
                pr_debug("detect failed, smbus byte data not supported!\n");
                return -ENODEV;
        }

        status = i2c_smbus_read_byte_data(client, ADM1021_REG_STATUS);
        conv_rate = i2c_smbus_read_byte_data(client,
                                             ADM1021_REG_CONV_RATE_R);
        config = i2c_smbus_read_byte_data(client, ADM1021_REG_CONFIG_R);

        /* Check unused bits */
        if ((status & 0x03) || (config & 0x3F) || (conv_rate & 0xF8)) {
                pr_debug("detect failed, chip not detected!\n");
                return -ENODEV;
        }

        /* Determine the chip type. */
        man_id = i2c_smbus_read_byte_data(client, ADM1021_REG_MAN_ID);
        dev_id = i2c_smbus_read_byte_data(client, ADM1021_REG_DEV_ID);

        if (man_id < 0 || dev_id < 0)
                return -ENODEV;

        if (man_id == 0x4d && dev_id == 0x01)
                type_name = "max1617a";
        else if (man_id == 0x41) {
                if ((dev_id & 0xF0) == 0x30)
                        type_name = "adm1023";
                else if ((dev_id & 0xF0) == 0x00)
                        type_name = "adm1021";
                else
                        return -ENODEV;
        } else if (man_id == 0x49)
                type_name = "thmc10";
        else if (man_id == 0x23)
                type_name = "gl523sm";
        else if (man_id == 0x54)
                type_name = "mc1066";
        else {
                int lte, rte, lhi, rhi, llo, rlo;

                /* extra checks for LM84 and MAX1617 to avoid misdetections */

                llo = i2c_smbus_read_byte_data(client, ADM1021_REG_THYST_R(0));
                rlo = i2c_smbus_read_byte_data(client, ADM1021_REG_THYST_R(1));

                /* fail if any of the additional register reads failed */
                if (llo < 0 || rlo < 0)
                        return -ENODEV;

                lte = i2c_smbus_read_byte_data(client, ADM1021_REG_TEMP(0));
                rte = i2c_smbus_read_byte_data(client, ADM1021_REG_TEMP(1));
                lhi = i2c_smbus_read_byte_data(client, ADM1021_REG_TOS_R(0));
                rhi = i2c_smbus_read_byte_data(client, ADM1021_REG_TOS_R(1));

                /*
                 * Fail for negative temperatures and negative high limits.
                 * This check also catches read errors on the tested registers.
                 */
                if ((s8)lte < 0 || (s8)rte < 0 || (s8)lhi < 0 || (s8)rhi < 0)
                        return -ENODEV;

                /* fail if all registers hold the same value */
                if (lte == rte && lte == lhi && lte == rhi && lte == llo
                    && lte == rlo)
                        return -ENODEV;

                /*
                 * LM84 Mfr ID is in a different place,
                 * and it has more unused bits.
                 */
                if (conv_rate == 0x00
                    && (config & 0x7F) == 0x00
                    && (status & 0xAB) == 0x00) {
                        type_name = "lm84";
                } else {
                        /* fail if low limits are larger than high limits */
                        if ((s8)llo > lhi || (s8)rlo > rhi)
                                return -ENODEV;
                        type_name = "max1617";
                }
        }

        pr_debug("Detected chip %s at adapter %d, address 0x%02x.\n",
                 type_name, i2c_adapter_id(adapter), client->addr);
        strlcpy(info->type, type_name, I2C_NAME_SIZE);

        return 0;
}

static void adm1021_init_client(struct i2c_client *client)
{
        /* Enable ADC and disable suspend mode */
        i2c_smbus_write_byte_data(client, ADM1021_REG_CONFIG_W,
                i2c_smbus_read_byte_data(client, ADM1021_REG_CONFIG_R) & 0xBF);
        /* Set Conversion rate to 1/sec (this can be tinkered with) */
        i2c_smbus_write_byte_data(client, ADM1021_REG_CONV_RATE_W, 0x04);
}

static int adm1021_probe(struct i2c_client *client,
                         const struct i2c_device_id *id)
{
        struct device *dev = &client->dev;
        struct adm1021_data *data;
        struct device *hwmon_dev;

        data = devm_kzalloc(dev, sizeof(struct adm1021_data), GFP_KERNEL);
        if (!data)
                return -ENOMEM;

        data->client = client;
        data->type = id->driver_data;
        mutex_init(&data->update_lock);

        /* Initialize the ADM1021 chip */
        if (data->type != lm84 && !read_only)
                adm1021_init_client(client);

        data->groups[0] = &adm1021_group;
        if (data->type != lm84)
                data->groups[1] = &adm1021_min_group;

        hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name,
                                                           data, data->groups);

        return PTR_ERR_OR_ZERO(hwmon_dev);
}

static const struct i2c_device_id adm1021_id[] = {
        { "adm1021", adm1021 },
        { "adm1023", adm1023 },
        { "max1617", max1617 },
        { "max1617a", max1617a },
        { "thmc10", thmc10 },
        { "lm84", lm84 },
        { "gl523sm", gl523sm },
        { "mc1066", mc1066 },
        { }
};
MODULE_DEVICE_TABLE(i2c, adm1021_id);

static struct i2c_driver adm1021_driver = {
        .class          = I2C_CLASS_HWMON,
        .driver = {
                .name   = "adm1021",
        },
        .probe          = adm1021_probe,
        .id_table       = adm1021_id,
        .detect         = adm1021_detect,
        .address_list   = normal_i2c,
};

module_i2c_driver(adm1021_driver);

MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl> and "
                "Philip Edelbrock <phil@netroedge.com>");
MODULE_DESCRIPTION("adm1021 driver");
MODULE_LICENSE("GPL");

module_param(read_only, bool, 0);
MODULE_PARM_DESC(read_only, "Don't set any values, read only mode");