/*
 * max6639.c - Support for Maxim MAX6639
 *
 * 2-Channel Temperature Monitor with Dual PWM Fan-Speed Controller
 *
 * Copyright (C) 2010, 2011 Roland Stigge <stigge@antcom.de>
 *
 * based on the initial MAX6639 support from semptian.net
 * by He Changqing <hechangqing@semptian.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>
#include <linux/i2c/max6639.h>

/* Addresses to scan */
static const unsigned short normal_i2c[] = { 0x2c, 0x2e, 0x2f, I2C_CLIENT_END };

/* The MAX6639 registers, valid channel numbers: 0, 1 */
#define MAX6639_REG_TEMP(ch)                    (0x00 + (ch))
#define MAX6639_REG_STATUS                      0x02
#define MAX6639_REG_OUTPUT_MASK                 0x03
#define MAX6639_REG_GCONFIG                     0x04
#define MAX6639_REG_TEMP_EXT(ch)                (0x05 + (ch))
#define MAX6639_REG_ALERT_LIMIT(ch)             (0x08 + (ch))
#define MAX6639_REG_OT_LIMIT(ch)                (0x0A + (ch))
#define MAX6639_REG_THERM_LIMIT(ch)             (0x0C + (ch))
#define MAX6639_REG_FAN_CONFIG1(ch)             (0x10 + (ch) * 4)
#define MAX6639_REG_FAN_CONFIG2a(ch)            (0x11 + (ch) * 4)
#define MAX6639_REG_FAN_CONFIG2b(ch)            (0x12 + (ch) * 4)
#define MAX6639_REG_FAN_CONFIG3(ch)             (0x13 + (ch) * 4)
#define MAX6639_REG_FAN_CNT(ch)                 (0x20 + (ch))
#define MAX6639_REG_TARGET_CNT(ch)              (0x22 + (ch))
#define MAX6639_REG_FAN_PPR(ch)                 (0x24 + (ch))
#define MAX6639_REG_TARGTDUTY(ch)               (0x26 + (ch))
#define MAX6639_REG_FAN_START_TEMP(ch)          (0x28 + (ch))
#define MAX6639_REG_DEVID                       0x3D
#define MAX6639_REG_MANUID                      0x3E
#define MAX6639_REG_DEVREV                      0x3F

/* Register bits */
#define MAX6639_GCONFIG_STANDBY                 0x80
#define MAX6639_GCONFIG_POR                     0x40
#define MAX6639_GCONFIG_DISABLE_TIMEOUT         0x20
#define MAX6639_GCONFIG_CH2_LOCAL               0x10
#define MAX6639_GCONFIG_PWM_FREQ_HI             0x08

#define MAX6639_FAN_CONFIG1_PWM                 0x80

#define MAX6639_FAN_CONFIG3_THERM_FULL_SPEED    0x40

static const int rpm_ranges[] = { 2000, 4000, 8000, 16000 };

#define FAN_FROM_REG(val, rpm_range)    ((val) == 0 || (val) == 255 ? \
                                0 : (rpm_ranges[rpm_range] * 30) / (val))
#define TEMP_LIMIT_TO_REG(val)  clamp_val((val) / 1000, 0, 255)

/*
 * Client data (each client gets its own)
 */
struct max6639_data {
        struct i2c_client *client;
        struct mutex update_lock;
        char valid;             /* !=0 if following fields are valid */
        unsigned long last_updated;     /* In jiffies */

        /* Register values sampled regularly */
        u16 temp[2];            /* Temperature, in 1/8 C, 0..255 C */
        bool temp_fault[2];     /* Detected temperature diode failure */
        u8 fan[2];              /* Register value: TACH count for fans >=30 */
        u8 status;              /* Detected channel alarms and fan failures */

        /* Register values only written to */
        u8 pwm[2];              /* Register value: Duty cycle 0..120 */
        u8 temp_therm[2];       /* THERM Temperature, 0..255 C (->_max) */
        u8 temp_alert[2];       /* ALERT Temperature, 0..255 C (->_crit) */
        u8 temp_ot[2];          /* OT Temperature, 0..255 C (->_emergency) */

        /* Register values initialized only once */
        u8 ppr;                 /* Pulses per rotation 0..3 for 1..4 ppr */
        u8 rpm_range;           /* Index in above rpm_ranges table */
};

static struct max6639_data *max6639_update_device(struct device *dev)
{
        struct max6639_data *data = dev_get_drvdata(dev);
        struct i2c_client *client = data->client;
        struct max6639_data *ret = data;
        int i;
        int status_reg;

        mutex_lock(&data->update_lock);

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

                dev_dbg(&client->dev, "Starting max6639 update\n");

                status_reg = i2c_smbus_read_byte_data(client,
                                                      MAX6639_REG_STATUS);
                if (status_reg < 0) {
                        ret = ERR_PTR(status_reg);
                        goto abort;
                }

                data->status = status_reg;

                for (i = 0; i < 2; i++) {
                        res = i2c_smbus_read_byte_data(client,
                                        MAX6639_REG_FAN_CNT(i));
                        if (res < 0) {
                                ret = ERR_PTR(res);
                                goto abort;
                        }
                        data->fan[i] = res;

                        res = i2c_smbus_read_byte_data(client,
                                        MAX6639_REG_TEMP_EXT(i));
                        if (res < 0) {
                                ret = ERR_PTR(res);
                                goto abort;
                        }
                        data->temp[i] = res >> 5;
                        data->temp_fault[i] = res & 0x01;

                        res = i2c_smbus_read_byte_data(client,
                                        MAX6639_REG_TEMP(i));
                        if (res < 0) {
                                ret = ERR_PTR(res);
                                goto abort;
                        }
                        data->temp[i] |= res << 3;
                }

                data->last_updated = jiffies;
                data->valid = 1;
        }
abort:
        mutex_unlock(&data->update_lock);

        return ret;
}

static ssize_t show_temp_input(struct device *dev,
                               struct device_attribute *dev_attr, char *buf)
{
        long temp;
        struct max6639_data *data = max6639_update_device(dev);
        struct sensor_device_attribute *attr = to_sensor_dev_attr(dev_attr);

        if (IS_ERR(data))
                return PTR_ERR(data);

        temp = data->temp[attr->index] * 125;
        return sprintf(buf, "%ld\n", temp);
}

static ssize_t show_temp_fault(struct device *dev,
                               struct device_attribute *dev_attr, char *buf)
{
        struct max6639_data *data = max6639_update_device(dev);
        struct sensor_device_attribute *attr = to_sensor_dev_attr(dev_attr);

        if (IS_ERR(data))
                return PTR_ERR(data);

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

static ssize_t show_temp_max(struct device *dev,
                             struct device_attribute *dev_attr, char *buf)
{
        struct sensor_device_attribute *attr = to_sensor_dev_attr(dev_attr);
        struct max6639_data *data = dev_get_drvdata(dev);

        return sprintf(buf, "%d\n", (data->temp_therm[attr->index] * 1000));
}

static ssize_t set_temp_max(struct device *dev,
                            struct device_attribute *dev_attr,
                            const char *buf, size_t count)
{
        struct sensor_device_attribute *attr = to_sensor_dev_attr(dev_attr);
        struct max6639_data *data = dev_get_drvdata(dev);
        struct i2c_client *client = data->client;
        unsigned long val;
        int res;

        res = kstrtoul(buf, 10, &val);
        if (res)
                return res;

        mutex_lock(&data->update_lock);
        data->temp_therm[attr->index] = TEMP_LIMIT_TO_REG(val);
        i2c_smbus_write_byte_data(client,
                                  MAX6639_REG_THERM_LIMIT(attr->index),
                                  data->temp_therm[attr->index]);
        mutex_unlock(&data->update_lock);
        return count;
}

static ssize_t show_temp_crit(struct device *dev,
                              struct device_attribute *dev_attr, char *buf)
{
        struct sensor_device_attribute *attr = to_sensor_dev_attr(dev_attr);
        struct max6639_data *data = dev_get_drvdata(dev);

        return sprintf(buf, "%d\n", (data->temp_alert[attr->index] * 1000));
}

static ssize_t set_temp_crit(struct device *dev,
                             struct device_attribute *dev_attr,
                             const char *buf, size_t count)
{
        struct sensor_device_attribute *attr = to_sensor_dev_attr(dev_attr);
        struct max6639_data *data = dev_get_drvdata(dev);
        struct i2c_client *client = data->client;
        unsigned long val;
        int res;

        res = kstrtoul(buf, 10, &val);
        if (res)
                return res;

        mutex_lock(&data->update_lock);
        data->temp_alert[attr->index] = TEMP_LIMIT_TO_REG(val);
        i2c_smbus_write_byte_data(client,
                                  MAX6639_REG_ALERT_LIMIT(attr->index),
                                  data->temp_alert[attr->index]);
        mutex_unlock(&data->update_lock);
        return count;
}

static ssize_t show_temp_emergency(struct device *dev,
                                   struct device_attribute *dev_attr,
                                   char *buf)
{
        struct sensor_device_attribute *attr = to_sensor_dev_attr(dev_attr);
        struct max6639_data *data = dev_get_drvdata(dev);

        return sprintf(buf, "%d\n", (data->temp_ot[attr->index] * 1000));
}

static ssize_t set_temp_emergency(struct device *dev,
                                  struct device_attribute *dev_attr,
                                  const char *buf, size_t count)
{
        struct sensor_device_attribute *attr = to_sensor_dev_attr(dev_attr);
        struct max6639_data *data = dev_get_drvdata(dev);
        struct i2c_client *client = data->client;
        unsigned long val;
        int res;

        res = kstrtoul(buf, 10, &val);
        if (res)
                return res;

        mutex_lock(&data->update_lock);
        data->temp_ot[attr->index] = TEMP_LIMIT_TO_REG(val);
        i2c_smbus_write_byte_data(client,
                                  MAX6639_REG_OT_LIMIT(attr->index),
                                  data->temp_ot[attr->index]);
        mutex_unlock(&data->update_lock);
        return count;
}

static ssize_t show_pwm(struct device *dev,
                        struct device_attribute *dev_attr, char *buf)
{
        struct sensor_device_attribute *attr = to_sensor_dev_attr(dev_attr);
        struct max6639_data *data = dev_get_drvdata(dev);

        return sprintf(buf, "%d\n", data->pwm[attr->index] * 255 / 120);
}

static ssize_t set_pwm(struct device *dev,
                       struct device_attribute *dev_attr,
                       const char *buf, size_t count)
{
        struct sensor_device_attribute *attr = to_sensor_dev_attr(dev_attr);
        struct max6639_data *data = dev_get_drvdata(dev);
        struct i2c_client *client = data->client;
        unsigned long val;
        int res;

        res = kstrtoul(buf, 10, &val);
        if (res)
                return res;

        val = clamp_val(val, 0, 255);

        mutex_lock(&data->update_lock);
        data->pwm[attr->index] = (u8)(val * 120 / 255);
        i2c_smbus_write_byte_data(client,
                                  MAX6639_REG_TARGTDUTY(attr->index),
                                  data->pwm[attr->index]);
        mutex_unlock(&data->update_lock);
        return count;
}

static ssize_t show_fan_input(struct device *dev,
                              struct device_attribute *dev_attr, char *buf)
{
        struct max6639_data *data = max6639_update_device(dev);
        struct sensor_device_attribute *attr = to_sensor_dev_attr(dev_attr);

        if (IS_ERR(data))
                return PTR_ERR(data);

        return sprintf(buf, "%d\n", FAN_FROM_REG(data->fan[attr->index],
                       data->rpm_range));
}

static ssize_t show_alarm(struct device *dev,
                          struct device_attribute *dev_attr, char *buf)
{
        struct max6639_data *data = max6639_update_device(dev);
        struct sensor_device_attribute *attr = to_sensor_dev_attr(dev_attr);

        if (IS_ERR(data))
                return PTR_ERR(data);

        return sprintf(buf, "%d\n", !!(data->status & (1 << attr->index)));
}

static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp_input, NULL, 0);
static SENSOR_DEVICE_ATTR(temp2_input, S_IRUGO, show_temp_input, NULL, 1);
static SENSOR_DEVICE_ATTR(temp1_fault, S_IRUGO, show_temp_fault, NULL, 0);
static SENSOR_DEVICE_ATTR(temp2_fault, S_IRUGO, show_temp_fault, NULL, 1);
static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO, show_temp_max,
                set_temp_max, 0);
static SENSOR_DEVICE_ATTR(temp2_max, S_IWUSR | S_IRUGO, show_temp_max,
                set_temp_max, 1);
static SENSOR_DEVICE_ATTR(temp1_crit, S_IWUSR | S_IRUGO, show_temp_crit,
                set_temp_crit, 0);
static SENSOR_DEVICE_ATTR(temp2_crit, S_IWUSR | S_IRUGO, show_temp_crit,
                set_temp_crit, 1);
static SENSOR_DEVICE_ATTR(temp1_emergency, S_IWUSR | S_IRUGO,
                show_temp_emergency, set_temp_emergency, 0);
static SENSOR_DEVICE_ATTR(temp2_emergency, S_IWUSR | S_IRUGO,
                show_temp_emergency, set_temp_emergency, 1);
static SENSOR_DEVICE_ATTR(pwm1, S_IWUSR | S_IRUGO, show_pwm, set_pwm, 0);
static SENSOR_DEVICE_ATTR(pwm2, S_IWUSR | S_IRUGO, show_pwm, set_pwm, 1);
static SENSOR_DEVICE_ATTR(fan1_input, S_IRUGO, show_fan_input, NULL, 0);
static SENSOR_DEVICE_ATTR(fan2_input, S_IRUGO, show_fan_input, NULL, 1);
static SENSOR_DEVICE_ATTR(fan1_fault, S_IRUGO, show_alarm, NULL, 1);
static SENSOR_DEVICE_ATTR(fan2_fault, S_IRUGO, show_alarm, NULL, 0);
static SENSOR_DEVICE_ATTR(temp1_max_alarm, S_IRUGO, show_alarm, NULL, 3);
static SENSOR_DEVICE_ATTR(temp2_max_alarm, S_IRUGO, show_alarm, NULL, 2);
static SENSOR_DEVICE_ATTR(temp1_crit_alarm, S_IRUGO, show_alarm, NULL, 7);
static SENSOR_DEVICE_ATTR(temp2_crit_alarm, S_IRUGO, show_alarm, NULL, 6);
static SENSOR_DEVICE_ATTR(temp1_emergency_alarm, S_IRUGO, show_alarm, NULL, 5);
static SENSOR_DEVICE_ATTR(temp2_emergency_alarm, S_IRUGO, show_alarm, NULL, 4);


static struct attribute *max6639_attrs[] = {
        &sensor_dev_attr_temp1_input.dev_attr.attr,
        &sensor_dev_attr_temp2_input.dev_attr.attr,
        &sensor_dev_attr_temp1_fault.dev_attr.attr,
        &sensor_dev_attr_temp2_fault.dev_attr.attr,
        &sensor_dev_attr_temp1_max.dev_attr.attr,
        &sensor_dev_attr_temp2_max.dev_attr.attr,
        &sensor_dev_attr_temp1_crit.dev_attr.attr,
        &sensor_dev_attr_temp2_crit.dev_attr.attr,
        &sensor_dev_attr_temp1_emergency.dev_attr.attr,
        &sensor_dev_attr_temp2_emergency.dev_attr.attr,
        &sensor_dev_attr_pwm1.dev_attr.attr,
        &sensor_dev_attr_pwm2.dev_attr.attr,
        &sensor_dev_attr_fan1_input.dev_attr.attr,
        &sensor_dev_attr_fan2_input.dev_attr.attr,
        &sensor_dev_attr_fan1_fault.dev_attr.attr,
        &sensor_dev_attr_fan2_fault.dev_attr.attr,
        &sensor_dev_attr_temp1_max_alarm.dev_attr.attr,
        &sensor_dev_attr_temp2_max_alarm.dev_attr.attr,
        &sensor_dev_attr_temp1_crit_alarm.dev_attr.attr,
        &sensor_dev_attr_temp2_crit_alarm.dev_attr.attr,
        &sensor_dev_attr_temp1_emergency_alarm.dev_attr.attr,
        &sensor_dev_attr_temp2_emergency_alarm.dev_attr.attr,
        NULL
};
ATTRIBUTE_GROUPS(max6639);

/*
 *  returns respective index in rpm_ranges table
 *  1 by default on invalid range
 */
static int rpm_range_to_reg(int range)
{
        int i;

        for (i = 0; i < ARRAY_SIZE(rpm_ranges); i++) {
                if (rpm_ranges[i] == range)
                        return i;
        }

        return 1; /* default: 4000 RPM */
}

static int max6639_init_client(struct i2c_client *client,
                               struct max6639_data *data)
{
        struct max6639_platform_data *max6639_info =
                dev_get_platdata(&client->dev);
        int i;
        int rpm_range = 1; /* default: 4000 RPM */
        int err;

        /* Reset chip to default values, see below for GCONFIG setup */
        err = i2c_smbus_write_byte_data(client, MAX6639_REG_GCONFIG,
                                  MAX6639_GCONFIG_POR);
        if (err)
                goto exit;

        /* Fans pulse per revolution is 2 by default */
        if (max6639_info && max6639_info->ppr > 0 &&
                        max6639_info->ppr < 5)
                data->ppr = max6639_info->ppr;
        else
                data->ppr = 2;
        data->ppr -= 1;

        if (max6639_info)
                rpm_range = rpm_range_to_reg(max6639_info->rpm_range);
        data->rpm_range = rpm_range;

        for (i = 0; i < 2; i++) {

                /* Set Fan pulse per revolution */
                err = i2c_smbus_write_byte_data(client,
                                MAX6639_REG_FAN_PPR(i),
                                data->ppr << 6);
                if (err)
                        goto exit;

                /* Fans config PWM, RPM */
                err = i2c_smbus_write_byte_data(client,
                        MAX6639_REG_FAN_CONFIG1(i),
                        MAX6639_FAN_CONFIG1_PWM | rpm_range);
                if (err)
                        goto exit;

                /* Fans PWM polarity high by default */
                if (max6639_info && max6639_info->pwm_polarity == 0)
                        err = i2c_smbus_write_byte_data(client,
                                MAX6639_REG_FAN_CONFIG2a(i), 0x00);
                else
                        err = i2c_smbus_write_byte_data(client,
                                MAX6639_REG_FAN_CONFIG2a(i), 0x02);
                if (err)
                        goto exit;

                /*
                 * /THERM full speed enable,
                 * PWM frequency 25kHz, see also GCONFIG below
                 */
                err = i2c_smbus_write_byte_data(client,
                        MAX6639_REG_FAN_CONFIG3(i),
                        MAX6639_FAN_CONFIG3_THERM_FULL_SPEED | 0x03);
                if (err)
                        goto exit;

                /* Max. temp. 80C/90C/100C */
                data->temp_therm[i] = 80;
                data->temp_alert[i] = 90;
                data->temp_ot[i] = 100;
                err = i2c_smbus_write_byte_data(client,
                                MAX6639_REG_THERM_LIMIT(i),
                                data->temp_therm[i]);
                if (err)
                        goto exit;
                err = i2c_smbus_write_byte_data(client,
                                MAX6639_REG_ALERT_LIMIT(i),
                                data->temp_alert[i]);
                if (err)
                        goto exit;
                err = i2c_smbus_write_byte_data(client,
                                MAX6639_REG_OT_LIMIT(i), data->temp_ot[i]);
                if (err)
                        goto exit;

                /* PWM 120/120 (i.e. 100%) */
                data->pwm[i] = 120;
                err = i2c_smbus_write_byte_data(client,
                                MAX6639_REG_TARGTDUTY(i), data->pwm[i]);
                if (err)
                        goto exit;
        }
        /* Start monitoring */
        err = i2c_smbus_write_byte_data(client, MAX6639_REG_GCONFIG,
                MAX6639_GCONFIG_DISABLE_TIMEOUT | MAX6639_GCONFIG_CH2_LOCAL |
                MAX6639_GCONFIG_PWM_FREQ_HI);
exit:
        return err;
}

/* Return 0 if detection is successful, -ENODEV otherwise */
static int max6639_detect(struct i2c_client *client,
                          struct i2c_board_info *info)
{
        struct i2c_adapter *adapter = client->adapter;
        int dev_id, manu_id;

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

        /* Actual detection via device and manufacturer ID */
        dev_id = i2c_smbus_read_byte_data(client, MAX6639_REG_DEVID);
        manu_id = i2c_smbus_read_byte_data(client, MAX6639_REG_MANUID);
        if (dev_id != 0x58 || manu_id != 0x4D)
                return -ENODEV;

        strlcpy(info->type, "max6639", I2C_NAME_SIZE);

        return 0;
}

static int max6639_probe(struct i2c_client *client,
                         const struct i2c_device_id *id)
{
        struct device *dev = &client->dev;
        struct max6639_data *data;
        struct device *hwmon_dev;
        int err;

        data = devm_kzalloc(dev, sizeof(struct max6639_data), GFP_KERNEL);
        if (!data)
                return -ENOMEM;

        data->client = client;
        mutex_init(&data->update_lock);

        /* Initialize the max6639 chip */
        err = max6639_init_client(client, data);
        if (err < 0)
                return err;

        hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name,
                                                           data,
                                                           max6639_groups);
        return PTR_ERR_OR_ZERO(hwmon_dev);
}

#ifdef CONFIG_PM_SLEEP
static int max6639_suspend(struct device *dev)
{
        struct i2c_client *client = to_i2c_client(dev);
        int data = i2c_smbus_read_byte_data(client, MAX6639_REG_GCONFIG);
        if (data < 0)
                return data;

        return i2c_smbus_write_byte_data(client,
                        MAX6639_REG_GCONFIG, data | MAX6639_GCONFIG_STANDBY);
}

static int max6639_resume(struct device *dev)
{
        struct i2c_client *client = to_i2c_client(dev);
        int data = i2c_smbus_read_byte_data(client, MAX6639_REG_GCONFIG);
        if (data < 0)
                return data;

        return i2c_smbus_write_byte_data(client,
                        MAX6639_REG_GCONFIG, data & ~MAX6639_GCONFIG_STANDBY);
}
#endif /* CONFIG_PM_SLEEP */

static const struct i2c_device_id max6639_id[] = {
        {"max6639", 0},
        { }
};

MODULE_DEVICE_TABLE(i2c, max6639_id);

static SIMPLE_DEV_PM_OPS(max6639_pm_ops, max6639_suspend, max6639_resume);

static struct i2c_driver max6639_driver = {
        .class = I2C_CLASS_HWMON,
        .driver = {
                   .name = "max6639",
                   .pm = &max6639_pm_ops,
                   },
        .probe = max6639_probe,
        .id_table = max6639_id,
        .detect = max6639_detect,
        .address_list = normal_i2c,
};

module_i2c_driver(max6639_driver);

MODULE_AUTHOR("Roland Stigge <stigge@antcom.de>");
MODULE_DESCRIPTION("max6639 driver");
MODULE_LICENSE("GPL");