/*
        fscpos.c - Kernel module for hardware monitoring with FSC Poseidon chips
        Copyright (C) 2004, 2005 Stefan Ott <stefan@desire.ch>

        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.
*/

/*
        fujitsu siemens poseidon chip,
        module based on the old fscpos module by Hermann Jung <hej@odn.de> and
        the fscher module by Reinhard Nissl <rnissl@gmx.de>

        original module based on lm80.c
        Copyright (C) 1998, 1999 Frodo Looijaard <frodol@dds.nl>
        and Philip Edelbrock <phil@netroedge.com>

        Thanks to Jean Delvare for reviewing my code and suggesting a lot of
        improvements.
*/

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

/*
 * Addresses to scan
 */
static const unsigned short normal_i2c[] = { 0x73, I2C_CLIENT_END };

/*
 * Insmod parameters
 */
I2C_CLIENT_INSMOD_1(fscpos);

/*
 * The FSCPOS registers
 */

/* chip identification */
#define FSCPOS_REG_IDENT_0              0x00
#define FSCPOS_REG_IDENT_1              0x01
#define FSCPOS_REG_IDENT_2              0x02
#define FSCPOS_REG_REVISION             0x03

/* global control and status */
#define FSCPOS_REG_EVENT_STATE          0x04
#define FSCPOS_REG_CONTROL              0x05

/* watchdog */
#define FSCPOS_REG_WDOG_PRESET          0x28
#define FSCPOS_REG_WDOG_STATE           0x23
#define FSCPOS_REG_WDOG_CONTROL         0x21

/* voltages */
#define FSCPOS_REG_VOLT_12              0x45
#define FSCPOS_REG_VOLT_5               0x42
#define FSCPOS_REG_VOLT_BATT            0x48

/* fans - the chip does not support minimum speed for fan2 */
static u8 FSCPOS_REG_PWM[] = { 0x55, 0x65 };
static u8 FSCPOS_REG_FAN_ACT[] = { 0x0e, 0x6b, 0xab };
static u8 FSCPOS_REG_FAN_STATE[] = { 0x0d, 0x62, 0xa2 };
static u8 FSCPOS_REG_FAN_RIPPLE[] = { 0x0f, 0x6f, 0xaf };

/* temperatures */
static u8 FSCPOS_REG_TEMP_ACT[] = { 0x64, 0x32, 0x35 };
static u8 FSCPOS_REG_TEMP_STATE[] = { 0x71, 0x81, 0x91 };

/*
 * Functions declaration
 */
static int fscpos_probe(struct i2c_client *client,
                        const struct i2c_device_id *id);
static int fscpos_detect(struct i2c_client *client, int kind,
                         struct i2c_board_info *info);
static int fscpos_remove(struct i2c_client *client);

static int fscpos_read_value(struct i2c_client *client, u8 reg);
static int fscpos_write_value(struct i2c_client *client, u8 reg, u8 value);
static struct fscpos_data *fscpos_update_device(struct device *dev);
static void fscpos_init_client(struct i2c_client *client);

static void reset_fan_alarm(struct i2c_client *client, int nr);

/*
 * Driver data (common to all clients)
 */
static const struct i2c_device_id fscpos_id[] = {
        { "fscpos", fscpos },
        { }
};

static struct i2c_driver fscpos_driver = {
        .class          = I2C_CLASS_HWMON,
        .driver = {
                .name   = "fscpos",
        },
        .probe          = fscpos_probe,
        .remove         = fscpos_remove,
        .id_table       = fscpos_id,
        .detect         = fscpos_detect,
        .address_data   = &addr_data,
};

/*
 * Client data (each client gets its own)
 */
struct fscpos_data {
        struct device *hwmon_dev;
        struct mutex update_lock;
        char valid;             /* 0 until following fields are valid */
        unsigned long last_updated;     /* In jiffies */

        /* register values */
        u8 revision;            /* revision of chip */
        u8 global_event;        /* global event status */
        u8 global_control;      /* global control register */
        u8 wdog_control;        /* watchdog control */
        u8 wdog_state;          /* watchdog status */
        u8 wdog_preset;         /* watchdog preset */
        u8 volt[3];             /* 12, 5, battery current */
        u8 temp_act[3];         /* temperature */
        u8 temp_status[3];      /* status of sensor */
        u8 fan_act[3];          /* fans revolutions per second */
        u8 fan_status[3];       /* fan status */
        u8 pwm[2];              /* fan min value for rps */
        u8 fan_ripple[3];       /* divider for rps */
};

/* Temperature */
#define TEMP_FROM_REG(val)      (((val) - 128) * 1000)

static ssize_t show_temp_input(struct fscpos_data *data, char *buf, int nr)
{
        return sprintf(buf, "%d\n", TEMP_FROM_REG(data->temp_act[nr - 1]));
}

static ssize_t show_temp_status(struct fscpos_data *data, char *buf, int nr)
{
        /* bits 2..7 reserved => mask with 0x03 */
        return sprintf(buf, "%u\n", data->temp_status[nr - 1] & 0x03);
}

static ssize_t show_temp_reset(struct fscpos_data *data, char *buf, int nr)
{
        return sprintf(buf, "1\n");
}

static ssize_t set_temp_reset(struct i2c_client *client, struct fscpos_data
                        *data, const char *buf, size_t count, int nr, int reg)
{
        unsigned long v = simple_strtoul(buf, NULL, 10);
        if (v != 1) {
                dev_err(&client->dev, "temp_reset value %ld not supported. "
                                        "Use 1 to reset the alarm!\n", v);
                return -EINVAL;
        }

        dev_info(&client->dev, "You used the temp_reset feature which has not "
                                "been proplerly tested. Please report your "
                                "experience to the module author.\n");

        /* Supported value: 2 (clears the status) */
        fscpos_write_value(client, FSCPOS_REG_TEMP_STATE[nr - 1], 2);
        return count;
}

/* Fans */
#define RPM_FROM_REG(val)       ((val) * 60)

static ssize_t show_fan_status(struct fscpos_data *data, char *buf, int nr)
{
        /* bits 0..1, 3..7 reserved => mask with 0x04 */
        return sprintf(buf, "%u\n", data->fan_status[nr - 1] & 0x04);
}

static ssize_t show_fan_input(struct fscpos_data *data, char *buf, int nr)
{
        return sprintf(buf, "%u\n", RPM_FROM_REG(data->fan_act[nr - 1]));
}

static ssize_t show_fan_ripple(struct fscpos_data *data, char *buf, int nr)
{
        /* bits 2..7 reserved => mask with 0x03 */
        return sprintf(buf, "%u\n", data->fan_ripple[nr - 1] & 0x03);
}

static ssize_t set_fan_ripple(struct i2c_client *client, struct fscpos_data
                        *data, const char *buf, size_t count, int nr, int reg)
{
        /* supported values: 2, 4, 8 */
        unsigned long v = simple_strtoul(buf, NULL, 10);

        switch (v) {
                case 2: v = 1; break;
                case 4: v = 2; break;
                case 8: v = 3; break;
        default:
                dev_err(&client->dev, "fan_ripple value %ld not supported. "
                                        "Must be one of 2, 4 or 8!\n", v);
                return -EINVAL;
        }
        
        mutex_lock(&data->update_lock);
        /* bits 2..7 reserved => mask with 0x03 */
        data->fan_ripple[nr - 1] &= ~0x03;
        data->fan_ripple[nr - 1] |= v;
        
        fscpos_write_value(client, reg, data->fan_ripple[nr - 1]);
        mutex_unlock(&data->update_lock);
        return count;
}

static ssize_t show_pwm(struct fscpos_data *data, char *buf, int nr)
{
        return sprintf(buf, "%u\n", data->pwm[nr - 1]);
}

static ssize_t set_pwm(struct i2c_client *client, struct fscpos_data *data,
                                const char *buf, size_t count, int nr, int reg)
{
        unsigned long v = simple_strtoul(buf, NULL, 10);

        /* Range: 0..255 */
        if (v < 0) v = 0;
        if (v > 255) v = 255;

        mutex_lock(&data->update_lock);
        data->pwm[nr - 1] = v;
        fscpos_write_value(client, reg, data->pwm[nr - 1]);
        mutex_unlock(&data->update_lock);
        return count;
}

static void reset_fan_alarm(struct i2c_client *client, int nr)
{
        fscpos_write_value(client, FSCPOS_REG_FAN_STATE[nr], 4);
}

/* Volts */
#define VOLT_FROM_REG(val, mult)        ((val) * (mult) / 255)

static ssize_t show_volt_12(struct device *dev, struct device_attribute *attr, char *buf)
{
        struct fscpos_data *data = fscpos_update_device(dev);
        return sprintf(buf, "%u\n", VOLT_FROM_REG(data->volt[0], 14200));
}

static ssize_t show_volt_5(struct device *dev, struct device_attribute *attr, char *buf)
{
        struct fscpos_data *data = fscpos_update_device(dev);
        return sprintf(buf, "%u\n", VOLT_FROM_REG(data->volt[1], 6600));
}

static ssize_t show_volt_batt(struct device *dev, struct device_attribute *attr, char *buf)
{
        struct fscpos_data *data = fscpos_update_device(dev);
        return sprintf(buf, "%u\n", VOLT_FROM_REG(data->volt[2], 3300));
}

/* Watchdog */
static ssize_t show_wdog_control(struct fscpos_data *data, char *buf)
{
        /* bits 0..3 reserved, bit 6 write only => mask with 0xb0 */
        return sprintf(buf, "%u\n", data->wdog_control & 0xb0);
}

static ssize_t set_wdog_control(struct i2c_client *client, struct fscpos_data
                                *data, const char *buf, size_t count, int reg)
{
        /* bits 0..3 reserved => mask with 0xf0 */
        unsigned long v = simple_strtoul(buf, NULL, 10) & 0xf0;

        mutex_lock(&data->update_lock);
        data->wdog_control &= ~0xf0;
        data->wdog_control |= v;
        fscpos_write_value(client, reg, data->wdog_control);
        mutex_unlock(&data->update_lock);
        return count;
}

static ssize_t show_wdog_state(struct fscpos_data *data, char *buf)
{
        /* bits 0, 2..7 reserved => mask with 0x02 */
        return sprintf(buf, "%u\n", data->wdog_state & 0x02);
}

static ssize_t set_wdog_state(struct i2c_client *client, struct fscpos_data
                                *data, const char *buf, size_t count, int reg)
{
        unsigned long v = simple_strtoul(buf, NULL, 10) & 0x02;

        /* Valid values: 2 (clear) */
        if (v != 2) {
                dev_err(&client->dev, "wdog_state value %ld not supported. "
                                        "Must be 2 to clear the state!\n", v);
                return -EINVAL;
        }

        mutex_lock(&data->update_lock);
        data->wdog_state &= ~v;
        fscpos_write_value(client, reg, v);
        mutex_unlock(&data->update_lock);
        return count;
}

static ssize_t show_wdog_preset(struct fscpos_data *data, char *buf)
{
        return sprintf(buf, "%u\n", data->wdog_preset);
}

static ssize_t set_wdog_preset(struct i2c_client *client, struct fscpos_data
                                *data, const char *buf, size_t count, int reg)
{
        unsigned long v = simple_strtoul(buf, NULL, 10) & 0xff;

        mutex_lock(&data->update_lock);
        data->wdog_preset = v;
        fscpos_write_value(client, reg, data->wdog_preset);
        mutex_unlock(&data->update_lock);
        return count;
}

/* Event */
static ssize_t show_event(struct device *dev, struct device_attribute *attr, char *buf)
{
        /* bits 5..7 reserved => mask with 0x1f */
        struct fscpos_data *data = fscpos_update_device(dev);
        return sprintf(buf, "%u\n", data->global_event & 0x9b);
}

/*
 * Sysfs stuff
 */
#define create_getter(kind, sub) \
        static ssize_t sysfs_show_##kind##sub(struct device *dev, struct device_attribute *attr, char *buf) \
        { \
                struct fscpos_data *data = fscpos_update_device(dev); \
                return show_##kind##sub(data, buf); \
        }

#define create_getter_n(kind, offset, sub) \
        static ssize_t sysfs_show_##kind##offset##sub(struct device *dev, struct device_attribute *attr, char\
                                                                        *buf) \
        { \
                struct fscpos_data *data = fscpos_update_device(dev); \
                return show_##kind##sub(data, buf, offset); \
        }

#define create_setter(kind, sub, reg) \
        static ssize_t sysfs_set_##kind##sub (struct device *dev, struct device_attribute *attr, const char \
                                                        *buf, size_t count) \
        { \
                struct i2c_client *client = to_i2c_client(dev); \
                struct fscpos_data *data = i2c_get_clientdata(client); \
                return set_##kind##sub(client, data, buf, count, reg); \
        }

#define create_setter_n(kind, offset, sub, reg) \
        static ssize_t sysfs_set_##kind##offset##sub (struct device *dev, struct device_attribute *attr, \
                                        const char *buf, size_t count) \
        { \
                struct i2c_client *client = to_i2c_client(dev); \
                struct fscpos_data *data = i2c_get_clientdata(client); \
                return set_##kind##sub(client, data, buf, count, offset, reg);\
        }

#define create_sysfs_device_ro(kind, sub, offset) \
        static DEVICE_ATTR(kind##offset##sub, S_IRUGO, \
                                        sysfs_show_##kind##offset##sub, NULL);

#define create_sysfs_device_rw(kind, sub, offset) \
        static DEVICE_ATTR(kind##offset##sub, S_IRUGO | S_IWUSR, \
                sysfs_show_##kind##offset##sub, sysfs_set_##kind##offset##sub);

#define sysfs_ro_n(kind, sub, offset) \
        create_getter_n(kind, offset, sub); \
        create_sysfs_device_ro(kind, sub, offset);

#define sysfs_rw_n(kind, sub, offset, reg) \
        create_getter_n(kind, offset, sub); \
        create_setter_n(kind, offset, sub, reg); \
        create_sysfs_device_rw(kind, sub, offset);

#define sysfs_rw(kind, sub, reg) \
        create_getter(kind, sub); \
        create_setter(kind, sub, reg); \
        create_sysfs_device_rw(kind, sub,);

#define sysfs_fan_with_min(offset, reg_status, reg_ripple, reg_min) \
        sysfs_fan(offset, reg_status, reg_ripple); \
        sysfs_rw_n(pwm,, offset, reg_min);

#define sysfs_fan(offset, reg_status, reg_ripple) \
        sysfs_ro_n(fan, _input, offset); \
        sysfs_ro_n(fan, _status, offset); \
        sysfs_rw_n(fan, _ripple, offset, reg_ripple);

#define sysfs_temp(offset, reg_status) \
        sysfs_ro_n(temp, _input, offset); \
        sysfs_ro_n(temp, _status, offset); \
        sysfs_rw_n(temp, _reset, offset, reg_status);

#define sysfs_watchdog(reg_wdog_preset, reg_wdog_state, reg_wdog_control) \
        sysfs_rw(wdog, _control, reg_wdog_control); \
        sysfs_rw(wdog, _preset, reg_wdog_preset); \
        sysfs_rw(wdog, _state, reg_wdog_state);

sysfs_fan_with_min(1, FSCPOS_REG_FAN_STATE[0], FSCPOS_REG_FAN_RIPPLE[0],
                                                        FSCPOS_REG_PWM[0]);
sysfs_fan_with_min(2, FSCPOS_REG_FAN_STATE[1], FSCPOS_REG_FAN_RIPPLE[1],
                                                        FSCPOS_REG_PWM[1]);
sysfs_fan(3, FSCPOS_REG_FAN_STATE[2], FSCPOS_REG_FAN_RIPPLE[2]);

sysfs_temp(1, FSCPOS_REG_TEMP_STATE[0]);
sysfs_temp(2, FSCPOS_REG_TEMP_STATE[1]);
sysfs_temp(3, FSCPOS_REG_TEMP_STATE[2]);

sysfs_watchdog(FSCPOS_REG_WDOG_PRESET, FSCPOS_REG_WDOG_STATE,
                                                FSCPOS_REG_WDOG_CONTROL);

static DEVICE_ATTR(event, S_IRUGO, show_event, NULL);
static DEVICE_ATTR(in0_input, S_IRUGO, show_volt_12, NULL);
static DEVICE_ATTR(in1_input, S_IRUGO, show_volt_5, NULL);
static DEVICE_ATTR(in2_input, S_IRUGO, show_volt_batt, NULL);

static struct attribute *fscpos_attributes[] = {
        &dev_attr_event.attr,
        &dev_attr_in0_input.attr,
        &dev_attr_in1_input.attr,
        &dev_attr_in2_input.attr,

        &dev_attr_wdog_control.attr,
        &dev_attr_wdog_preset.attr,
        &dev_attr_wdog_state.attr,

        &dev_attr_temp1_input.attr,
        &dev_attr_temp1_status.attr,
        &dev_attr_temp1_reset.attr,
        &dev_attr_temp2_input.attr,
        &dev_attr_temp2_status.attr,
        &dev_attr_temp2_reset.attr,
        &dev_attr_temp3_input.attr,
        &dev_attr_temp3_status.attr,
        &dev_attr_temp3_reset.attr,

        &dev_attr_fan1_input.attr,
        &dev_attr_fan1_status.attr,
        &dev_attr_fan1_ripple.attr,
        &dev_attr_pwm1.attr,
        &dev_attr_fan2_input.attr,
        &dev_attr_fan2_status.attr,
        &dev_attr_fan2_ripple.attr,
        &dev_attr_pwm2.attr,
        &dev_attr_fan3_input.attr,
        &dev_attr_fan3_status.attr,
        &dev_attr_fan3_ripple.attr,
        NULL
};

static const struct attribute_group fscpos_group = {
        .attrs = fscpos_attributes,
};

/* Return 0 if detection is successful, -ENODEV otherwise */
static int fscpos_detect(struct i2c_client *new_client, int kind,
                         struct i2c_board_info *info)
{
        struct i2c_adapter *adapter = new_client->adapter;

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

        /* Do the remaining detection unless force or force_fscpos parameter */
        if (kind < 0) {
                if ((fscpos_read_value(new_client, FSCPOS_REG_IDENT_0)
                        != 0x50) /* 'P' */
                || (fscpos_read_value(new_client, FSCPOS_REG_IDENT_1)
                        != 0x45) /* 'E' */
                || (fscpos_read_value(new_client, FSCPOS_REG_IDENT_2)
                        != 0x47))/* 'G' */
                        return -ENODEV;
        }

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

        return 0;
}

static int fscpos_probe(struct i2c_client *new_client,
                        const struct i2c_device_id *id)
{
        struct fscpos_data *data;
        int err;

        data = kzalloc(sizeof(struct fscpos_data), GFP_KERNEL);
        if (!data) {
                err = -ENOMEM;
                goto exit;
        }

        i2c_set_clientdata(new_client, data);
        data->valid = 0;
        mutex_init(&data->update_lock);

        /* Inizialize the fscpos chip */
        fscpos_init_client(new_client);

        /* Announce that the chip was found */
        dev_info(&new_client->dev, "Found fscpos chip, rev %u\n", data->revision);

        /* Register sysfs hooks */
        if ((err = sysfs_create_group(&new_client->dev.kobj, &fscpos_group)))
                goto exit_free;

        data->hwmon_dev = hwmon_device_register(&new_client->dev);
        if (IS_ERR(data->hwmon_dev)) {
                err = PTR_ERR(data->hwmon_dev);
                goto exit_remove_files;
        }

        return 0;

exit_remove_files:
        sysfs_remove_group(&new_client->dev.kobj, &fscpos_group);
exit_free:
        kfree(data);
exit:
        return err;
}

static int fscpos_remove(struct i2c_client *client)
{
        struct fscpos_data *data = i2c_get_clientdata(client);

        hwmon_device_unregister(data->hwmon_dev);
        sysfs_remove_group(&client->dev.kobj, &fscpos_group);

        kfree(data);
        return 0;
}

static int fscpos_read_value(struct i2c_client *client, u8 reg)
{
        dev_dbg(&client->dev, "Read reg 0x%02x\n", reg);
        return i2c_smbus_read_byte_data(client, reg);
}

static int fscpos_write_value(struct i2c_client *client, u8 reg, u8 value)
{
        dev_dbg(&client->dev, "Write reg 0x%02x, val 0x%02x\n", reg, value);
        return i2c_smbus_write_byte_data(client, reg, value);
}

/* Called when we have found a new FSCPOS chip */
static void fscpos_init_client(struct i2c_client *client)
{
        struct fscpos_data *data = i2c_get_clientdata(client);

        /* read revision from chip */
        data->revision = fscpos_read_value(client, FSCPOS_REG_REVISION);
}

static struct fscpos_data *fscpos_update_device(struct device *dev)
{
        struct i2c_client *client = to_i2c_client(dev);
        struct fscpos_data *data = i2c_get_clientdata(client);

        mutex_lock(&data->update_lock);

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

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

                for (i = 0; i < 3; i++) {
                        data->temp_act[i] = fscpos_read_value(client,
                                                FSCPOS_REG_TEMP_ACT[i]);
                        data->temp_status[i] = fscpos_read_value(client,
                                                FSCPOS_REG_TEMP_STATE[i]);
                        data->fan_act[i] = fscpos_read_value(client,
                                                FSCPOS_REG_FAN_ACT[i]);
                        data->fan_status[i] = fscpos_read_value(client,
                                                FSCPOS_REG_FAN_STATE[i]);
                        data->fan_ripple[i] = fscpos_read_value(client,
                                                FSCPOS_REG_FAN_RIPPLE[i]);
                        if (i < 2) {
                                /* fan2_min is not supported by the chip */
                                data->pwm[i] = fscpos_read_value(client,
                                                        FSCPOS_REG_PWM[i]);
                        }
                        /* reset fan status if speed is back to > 0 */
                        if (data->fan_status[i] != 0 && data->fan_act[i] > 0) {
                                reset_fan_alarm(client, i);
                        }
                }

                data->volt[0] = fscpos_read_value(client, FSCPOS_REG_VOLT_12);
                data->volt[1] = fscpos_read_value(client, FSCPOS_REG_VOLT_5);
                data->volt[2] = fscpos_read_value(client, FSCPOS_REG_VOLT_BATT);

                data->wdog_preset = fscpos_read_value(client,
                                                        FSCPOS_REG_WDOG_PRESET);
                data->wdog_state = fscpos_read_value(client,
                                                        FSCPOS_REG_WDOG_STATE);
                data->wdog_control = fscpos_read_value(client,
                                                FSCPOS_REG_WDOG_CONTROL);

                data->global_event = fscpos_read_value(client,
                                                FSCPOS_REG_EVENT_STATE);

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

static int __init sm_fscpos_init(void)
{
        return i2c_add_driver(&fscpos_driver);
}

static void __exit sm_fscpos_exit(void)
{
        i2c_del_driver(&fscpos_driver);
}

MODULE_AUTHOR("Stefan Ott <stefan@desire.ch> based on work from Hermann Jung "
                                "<hej@odn.de>, Frodo Looijaard <frodol@dds.nl>"
                                " and Philip Edelbrock <phil@netroedge.com>");
MODULE_DESCRIPTION("fujitsu siemens poseidon chip driver");
MODULE_LICENSE("GPL");

module_init(sm_fscpos_init);
module_exit(sm_fscpos_exit);