/*
 * adt7x10.c - Part of lm_sensors, Linux kernel modules for hardware
 *       monitoring
 * This driver handles the ADT7410 and compatible digital temperature sensors.
 * Hartmut Knaack <knaack.h@gmx.de> 2012-07-22
 * based on lm75.c by Frodo Looijaard <frodol@dds.nl>
 * and adt7410.c from iio-staging by Sonic Zhang <sonic.zhang@analog.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/hwmon.h>
#include <linux/hwmon-sysfs.h>
#include <linux/err.h>
#include <linux/mutex.h>
#include <linux/delay.h>
#include <linux/interrupt.h>

#include "adt7x10.h"

/*
 * ADT7X10 status
 */
#define ADT7X10_STAT_T_LOW              (1 << 4)
#define ADT7X10_STAT_T_HIGH             (1 << 5)
#define ADT7X10_STAT_T_CRIT             (1 << 6)
#define ADT7X10_STAT_NOT_RDY            (1 << 7)

/*
 * ADT7X10 config
 */
#define ADT7X10_FAULT_QUEUE_MASK        (1 << 0 | 1 << 1)
#define ADT7X10_CT_POLARITY             (1 << 2)
#define ADT7X10_INT_POLARITY            (1 << 3)
#define ADT7X10_EVENT_MODE              (1 << 4)
#define ADT7X10_MODE_MASK               (1 << 5 | 1 << 6)
#define ADT7X10_FULL                    (0 << 5 | 0 << 6)
#define ADT7X10_PD                      (1 << 5 | 1 << 6)
#define ADT7X10_RESOLUTION              (1 << 7)

/*
 * ADT7X10 masks
 */
#define ADT7X10_T13_VALUE_MASK          0xFFF8
#define ADT7X10_T_HYST_MASK             0xF

/* straight from the datasheet */
#define ADT7X10_TEMP_MIN (-55000)
#define ADT7X10_TEMP_MAX 150000

/* Each client has this additional data */
struct adt7x10_data {
        const struct adt7x10_ops *ops;
        const char              *name;
        struct device           *hwmon_dev;
        struct mutex            update_lock;
        u8                      config;
        u8                      oldconfig;
        bool                    valid;          /* true if registers valid */
        unsigned long           last_updated;   /* In jiffies */
        s16                     temp[4];        /* Register values,
                                                   0 = input
                                                   1 = high
                                                   2 = low
                                                   3 = critical */
        u8                      hyst;           /* hysteresis offset */
};

static int adt7x10_read_byte(struct device *dev, u8 reg)
{
        struct adt7x10_data *d = dev_get_drvdata(dev);
        return d->ops->read_byte(dev, reg);
}

static int adt7x10_write_byte(struct device *dev, u8 reg, u8 data)
{
        struct adt7x10_data *d = dev_get_drvdata(dev);
        return d->ops->write_byte(dev, reg, data);
}

static int adt7x10_read_word(struct device *dev, u8 reg)
{
        struct adt7x10_data *d = dev_get_drvdata(dev);
        return d->ops->read_word(dev, reg);
}

static int adt7x10_write_word(struct device *dev, u8 reg, u16 data)
{
        struct adt7x10_data *d = dev_get_drvdata(dev);
        return d->ops->write_word(dev, reg, data);
}

static const u8 ADT7X10_REG_TEMP[4] = {
        ADT7X10_TEMPERATURE,            /* input */
        ADT7X10_T_ALARM_HIGH,           /* high */
        ADT7X10_T_ALARM_LOW,            /* low */
        ADT7X10_T_CRIT,                 /* critical */
};

static irqreturn_t adt7x10_irq_handler(int irq, void *private)
{
        struct device *dev = private;
        int status;

        status = adt7x10_read_byte(dev, ADT7X10_STATUS);
        if (status < 0)
                return IRQ_HANDLED;

        if (status & ADT7X10_STAT_T_HIGH)
                sysfs_notify(&dev->kobj, NULL, "temp1_max_alarm");
        if (status & ADT7X10_STAT_T_LOW)
                sysfs_notify(&dev->kobj, NULL, "temp1_min_alarm");
        if (status & ADT7X10_STAT_T_CRIT)
                sysfs_notify(&dev->kobj, NULL, "temp1_crit_alarm");

        return IRQ_HANDLED;
}

static int adt7x10_temp_ready(struct device *dev)
{
        int i, status;

        for (i = 0; i < 6; i++) {
                status = adt7x10_read_byte(dev, ADT7X10_STATUS);
                if (status < 0)
                        return status;
                if (!(status & ADT7X10_STAT_NOT_RDY))
                        return 0;
                msleep(60);
        }
        return -ETIMEDOUT;
}

static int adt7x10_update_temp(struct device *dev)
{
        struct adt7x10_data *data = dev_get_drvdata(dev);
        int ret = 0;

        mutex_lock(&data->update_lock);

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

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

                ret = adt7x10_temp_ready(dev); /* check for new value */
                if (ret)
                        goto abort;

                temp = adt7x10_read_word(dev, ADT7X10_REG_TEMP[0]);
                if (temp < 0) {
                        ret = temp;
                        dev_dbg(dev, "Failed to read value: reg %d, error %d\n",
                                ADT7X10_REG_TEMP[0], ret);
                        goto abort;
                }
                data->temp[0] = temp;
                data->last_updated = jiffies;
                data->valid = true;
        }

abort:
        mutex_unlock(&data->update_lock);
        return ret;
}

static int adt7x10_fill_cache(struct device *dev)
{
        struct adt7x10_data *data = dev_get_drvdata(dev);
        int ret;
        int i;

        for (i = 1; i < ARRAY_SIZE(data->temp); i++) {
                ret = adt7x10_read_word(dev, ADT7X10_REG_TEMP[i]);
                if (ret < 0) {
                        dev_dbg(dev, "Failed to read value: reg %d, error %d\n",
                                ADT7X10_REG_TEMP[i], ret);
                        return ret;
                }
                data->temp[i] = ret;
        }

        ret = adt7x10_read_byte(dev, ADT7X10_T_HYST);
        if (ret < 0) {
                dev_dbg(dev, "Failed to read value: reg %d, error %d\n",
                                ADT7X10_T_HYST, ret);
                return ret;
        }
        data->hyst = ret;

        return 0;
}

static s16 ADT7X10_TEMP_TO_REG(long temp)
{
        return DIV_ROUND_CLOSEST(clamp_val(temp, ADT7X10_TEMP_MIN,
                                               ADT7X10_TEMP_MAX) * 128, 1000);
}

static int ADT7X10_REG_TO_TEMP(struct adt7x10_data *data, s16 reg)
{
        /* in 13 bit mode, bits 0-2 are status flags - mask them out */
        if (!(data->config & ADT7X10_RESOLUTION))
                reg &= ADT7X10_T13_VALUE_MASK;
        /*
         * temperature is stored in twos complement format, in steps of
         * 1/128°C
         */
        return DIV_ROUND_CLOSEST(reg * 1000, 128);
}

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

/* sysfs attributes for hwmon */

static ssize_t adt7x10_show_temp(struct device *dev,
                                 struct device_attribute *da,
                                 char *buf)
{
        struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
        struct adt7x10_data *data = dev_get_drvdata(dev);


        if (attr->index == 0) {
                int ret;

                ret = adt7x10_update_temp(dev);
                if (ret)
                        return ret;
        }

        return sprintf(buf, "%d\n", ADT7X10_REG_TO_TEMP(data,
                       data->temp[attr->index]));
}

static ssize_t adt7x10_set_temp(struct device *dev,
                                struct device_attribute *da,
                                const char *buf, size_t count)
{
        struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
        struct adt7x10_data *data = dev_get_drvdata(dev);
        int nr = attr->index;
        long temp;
        int ret;

        ret = kstrtol(buf, 10, &temp);
        if (ret)
                return ret;

        mutex_lock(&data->update_lock);
        data->temp[nr] = ADT7X10_TEMP_TO_REG(temp);
        ret = adt7x10_write_word(dev, ADT7X10_REG_TEMP[nr], data->temp[nr]);
        if (ret)
                count = ret;
        mutex_unlock(&data->update_lock);
        return count;
}

static ssize_t adt7x10_show_t_hyst(struct device *dev,
                                   struct device_attribute *da,
                                   char *buf)
{
        struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
        struct adt7x10_data *data = dev_get_drvdata(dev);
        int nr = attr->index;
        int hyst;

        hyst = (data->hyst & ADT7X10_T_HYST_MASK) * 1000;

        /*
         * hysteresis is stored as a 4 bit offset in the device, convert it
         * to an absolute value
         */
        if (nr == 2)    /* min has positive offset, others have negative */
                hyst = -hyst;
        return sprintf(buf, "%d\n",
                       ADT7X10_REG_TO_TEMP(data, data->temp[nr]) - hyst);
}

static ssize_t adt7x10_set_t_hyst(struct device *dev,
                                  struct device_attribute *da,
                                  const char *buf, size_t count)
{
        struct adt7x10_data *data = dev_get_drvdata(dev);
        int limit, ret;
        long hyst;

        ret = kstrtol(buf, 10, &hyst);
        if (ret)
                return ret;
        /* convert absolute hysteresis value to a 4 bit delta value */
        limit = ADT7X10_REG_TO_TEMP(data, data->temp[1]);
        hyst = clamp_val(hyst, ADT7X10_TEMP_MIN, ADT7X10_TEMP_MAX);
        data->hyst = clamp_val(DIV_ROUND_CLOSEST(limit - hyst, 1000),
                                   0, ADT7X10_T_HYST_MASK);
        ret = adt7x10_write_byte(dev, ADT7X10_T_HYST, data->hyst);
        if (ret)
                return ret;

        return count;
}

static ssize_t adt7x10_show_alarm(struct device *dev,
                                  struct device_attribute *da,
                                  char *buf)
{
        struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
        int ret;

        ret = adt7x10_read_byte(dev, ADT7X10_STATUS);
        if (ret < 0)
                return ret;

        return sprintf(buf, "%d\n", !!(ret & attr->index));
}

static ssize_t name_show(struct device *dev, struct device_attribute *da,
                         char *buf)
{
        struct adt7x10_data *data = dev_get_drvdata(dev);

        return sprintf(buf, "%s\n", data->name);
}

static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, adt7x10_show_temp, NULL, 0);
static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO,
                          adt7x10_show_temp, adt7x10_set_temp, 1);
static SENSOR_DEVICE_ATTR(temp1_min, S_IWUSR | S_IRUGO,
                          adt7x10_show_temp, adt7x10_set_temp, 2);
static SENSOR_DEVICE_ATTR(temp1_crit, S_IWUSR | S_IRUGO,
                          adt7x10_show_temp, adt7x10_set_temp, 3);
static SENSOR_DEVICE_ATTR(temp1_max_hyst, S_IWUSR | S_IRUGO,
                          adt7x10_show_t_hyst, adt7x10_set_t_hyst, 1);
static SENSOR_DEVICE_ATTR(temp1_min_hyst, S_IRUGO,
                          adt7x10_show_t_hyst, NULL, 2);
static SENSOR_DEVICE_ATTR(temp1_crit_hyst, S_IRUGO,
                          adt7x10_show_t_hyst, NULL, 3);
static SENSOR_DEVICE_ATTR(temp1_min_alarm, S_IRUGO, adt7x10_show_alarm,
                          NULL, ADT7X10_STAT_T_LOW);
static SENSOR_DEVICE_ATTR(temp1_max_alarm, S_IRUGO, adt7x10_show_alarm,
                          NULL, ADT7X10_STAT_T_HIGH);
static SENSOR_DEVICE_ATTR(temp1_crit_alarm, S_IRUGO, adt7x10_show_alarm,
                          NULL, ADT7X10_STAT_T_CRIT);
static DEVICE_ATTR_RO(name);

static struct attribute *adt7x10_attributes[] = {
        &sensor_dev_attr_temp1_input.dev_attr.attr,
        &sensor_dev_attr_temp1_max.dev_attr.attr,
        &sensor_dev_attr_temp1_min.dev_attr.attr,
        &sensor_dev_attr_temp1_crit.dev_attr.attr,
        &sensor_dev_attr_temp1_max_hyst.dev_attr.attr,
        &sensor_dev_attr_temp1_min_hyst.dev_attr.attr,
        &sensor_dev_attr_temp1_crit_hyst.dev_attr.attr,
        &sensor_dev_attr_temp1_min_alarm.dev_attr.attr,
        &sensor_dev_attr_temp1_max_alarm.dev_attr.attr,
        &sensor_dev_attr_temp1_crit_alarm.dev_attr.attr,
        NULL
};

static const struct attribute_group adt7x10_group = {
        .attrs = adt7x10_attributes,
};

int adt7x10_probe(struct device *dev, const char *name, int irq,
                  const struct adt7x10_ops *ops)
{
        struct adt7x10_data *data;
        int ret;

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

        data->ops = ops;
        data->name = name;

        dev_set_drvdata(dev, data);
        mutex_init(&data->update_lock);

        /* configure as specified */
        ret = adt7x10_read_byte(dev, ADT7X10_CONFIG);
        if (ret < 0) {
                dev_dbg(dev, "Can't read config? %d\n", ret);
                return ret;
        }
        data->oldconfig = ret;

        /*
         * Set to 16 bit resolution, continous conversion and comparator mode.
         */
        data->config = data->oldconfig;
        data->config &= ~(ADT7X10_MODE_MASK | ADT7X10_CT_POLARITY |
                        ADT7X10_INT_POLARITY);
        data->config |= ADT7X10_FULL | ADT7X10_RESOLUTION | ADT7X10_EVENT_MODE;

        if (data->config != data->oldconfig) {
                ret = adt7x10_write_byte(dev, ADT7X10_CONFIG, data->config);
                if (ret)
                        return ret;
        }
        dev_dbg(dev, "Config %02x\n", data->config);

        ret = adt7x10_fill_cache(dev);
        if (ret)
                goto exit_restore;

        /* Register sysfs hooks */
        ret = sysfs_create_group(&dev->kobj, &adt7x10_group);
        if (ret)
                goto exit_restore;

        /*
         * The I2C device will already have it's own 'name' attribute, but for
         * the SPI device we need to register it. name will only be non NULL if
         * the device doesn't register the 'name' attribute on its own.
         */
        if (name) {
                ret = device_create_file(dev, &dev_attr_name);
                if (ret)
                        goto exit_remove;
        }

        data->hwmon_dev = hwmon_device_register(dev);
        if (IS_ERR(data->hwmon_dev)) {
                ret = PTR_ERR(data->hwmon_dev);
                goto exit_remove_name;
        }

        if (irq > 0) {
                ret = request_threaded_irq(irq, NULL, adt7x10_irq_handler,
                                IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
                                dev_name(dev), dev);
                if (ret)
                        goto exit_hwmon_device_unregister;
        }

        return 0;

exit_hwmon_device_unregister:
        hwmon_device_unregister(data->hwmon_dev);
exit_remove_name:
        if (name)
                device_remove_file(dev, &dev_attr_name);
exit_remove:
        sysfs_remove_group(&dev->kobj, &adt7x10_group);
exit_restore:
        adt7x10_write_byte(dev, ADT7X10_CONFIG, data->oldconfig);
        return ret;
}
EXPORT_SYMBOL_GPL(adt7x10_probe);

int adt7x10_remove(struct device *dev, int irq)
{
        struct adt7x10_data *data = dev_get_drvdata(dev);

        if (irq > 0)
                free_irq(irq, dev);

        hwmon_device_unregister(data->hwmon_dev);
        if (data->name)
                device_remove_file(dev, &dev_attr_name);
        sysfs_remove_group(&dev->kobj, &adt7x10_group);
        if (data->oldconfig != data->config)
                adt7x10_write_byte(dev, ADT7X10_CONFIG, data->oldconfig);
        return 0;
}
EXPORT_SYMBOL_GPL(adt7x10_remove);

#ifdef CONFIG_PM_SLEEP

static int adt7x10_suspend(struct device *dev)
{
        struct adt7x10_data *data = dev_get_drvdata(dev);

        return adt7x10_write_byte(dev, ADT7X10_CONFIG,
                data->config | ADT7X10_PD);
}

static int adt7x10_resume(struct device *dev)
{
        struct adt7x10_data *data = dev_get_drvdata(dev);

        return adt7x10_write_byte(dev, ADT7X10_CONFIG, data->config);
}

SIMPLE_DEV_PM_OPS(adt7x10_dev_pm_ops, adt7x10_suspend, adt7x10_resume);
EXPORT_SYMBOL_GPL(adt7x10_dev_pm_ops);

#endif /* CONFIG_PM_SLEEP */

MODULE_AUTHOR("Hartmut Knaack");
MODULE_DESCRIPTION("ADT7410/ADT7420, ADT7310/ADT7320 common code");
MODULE_LICENSE("GPL");