// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *  ds620.c - Support for temperature sensor and thermostat DS620
 *
 *  Copyright (C) 2010, 2011 Roland Stigge <stigge@antcom.de>
 *
 *  based on ds1621.c by Christian W. Zuckschwerdt  <zany@triq.net>
 */

#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/sysfs.h>
#include <linux/platform_data/ds620.h>

/*
 * Many DS620 constants specified below
 *  15   14   13   12   11   10   09    08
 * |Done|NVB |THF |TLF |R1  |R0  |AUTOC|1SHOT|
 *
 *  07   06   05   04   03   02   01    00
 * |PO2 |PO1 |A2  |A1  |A0  |    |     |     |
 */
#define DS620_REG_CONFIG_DONE           0x8000
#define DS620_REG_CONFIG_NVB            0x4000
#define DS620_REG_CONFIG_THF            0x2000
#define DS620_REG_CONFIG_TLF            0x1000
#define DS620_REG_CONFIG_R1             0x0800
#define DS620_REG_CONFIG_R0             0x0400
#define DS620_REG_CONFIG_AUTOC          0x0200
#define DS620_REG_CONFIG_1SHOT          0x0100
#define DS620_REG_CONFIG_PO2            0x0080
#define DS620_REG_CONFIG_PO1            0x0040
#define DS620_REG_CONFIG_A2             0x0020
#define DS620_REG_CONFIG_A1             0x0010
#define DS620_REG_CONFIG_A0             0x0008

/* The DS620 registers */
static const u8 DS620_REG_TEMP[3] = {
        0xAA,                   /* input, word, RO */
        0xA2,                   /* min, word, RW */
        0xA0,                   /* max, word, RW */
};

#define DS620_REG_CONF          0xAC    /* word, RW */
#define DS620_COM_START         0x51    /* no data */
#define DS620_COM_STOP          0x22    /* no data */

/* Each client has this additional data */
struct ds620_data {
        struct i2c_client *client;
        struct mutex update_lock;
        bool valid;             /* true if following fields are valid */
        unsigned long last_updated;     /* In jiffies */

        s16 temp[3];            /* Register values, word */
};

static void ds620_init_client(struct i2c_client *client)
{
        struct ds620_platform_data *ds620_info = dev_get_platdata(&client->dev);
        u16 conf, new_conf;

        new_conf = conf =
            i2c_smbus_read_word_swapped(client, DS620_REG_CONF);

        /* switch to continuous conversion mode */
        new_conf &= ~DS620_REG_CONFIG_1SHOT;
        /* already high at power-on, but don't trust the BIOS! */
        new_conf |= DS620_REG_CONFIG_PO2;
        /* thermostat mode according to platform data */
        if (ds620_info && ds620_info->pomode == 1)
                new_conf &= ~DS620_REG_CONFIG_PO1; /* PO_LOW */
        else if (ds620_info && ds620_info->pomode == 2)
                new_conf |= DS620_REG_CONFIG_PO1; /* PO_HIGH */
        else
                new_conf &= ~DS620_REG_CONFIG_PO2; /* always low */
        /* with highest precision */
        new_conf |= DS620_REG_CONFIG_R1 | DS620_REG_CONFIG_R0;

        if (conf != new_conf)
                i2c_smbus_write_word_swapped(client, DS620_REG_CONF, new_conf);

        /* start conversion */
        i2c_smbus_write_byte(client, DS620_COM_START);
}

static struct ds620_data *ds620_update_client(struct device *dev)
{
        struct ds620_data *data = dev_get_drvdata(dev);
        struct i2c_client *client = data->client;
        struct ds620_data *ret = data;

        mutex_lock(&data->update_lock);

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

                dev_dbg(&client->dev, "Starting ds620 update\n");

                for (i = 0; i < ARRAY_SIZE(data->temp); i++) {
                        res = i2c_smbus_read_word_swapped(client,
                                                          DS620_REG_TEMP[i]);
                        if (res < 0) {
                                ret = ERR_PTR(res);
                                goto abort;
                        }

                        data->temp[i] = res;
                }

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

        return ret;
}

static ssize_t temp_show(struct device *dev, struct device_attribute *da,
                         char *buf)
{
        struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
        struct ds620_data *data = ds620_update_client(dev);

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

        return sprintf(buf, "%d\n", ((data->temp[attr->index] / 8) * 625) / 10);
}

static ssize_t temp_store(struct device *dev, struct device_attribute *da,
                          const char *buf, size_t count)
{
        int res;
        long val;

        struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
        struct ds620_data *data = dev_get_drvdata(dev);
        struct i2c_client *client = data->client;

        res = kstrtol(buf, 10, &val);

        if (res)
                return res;

        val = (clamp_val(val, -128000, 128000) * 10 / 625) * 8;

        mutex_lock(&data->update_lock);
        data->temp[attr->index] = val;
        i2c_smbus_write_word_swapped(client, DS620_REG_TEMP[attr->index],
                                     data->temp[attr->index]);
        mutex_unlock(&data->update_lock);
        return count;
}

static ssize_t alarm_show(struct device *dev, struct device_attribute *da,
                          char *buf)
{
        struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
        struct ds620_data *data = ds620_update_client(dev);
        struct i2c_client *client;
        u16 conf, new_conf;
        int res;

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

        client = data->client;

        /* reset alarms if necessary */
        res = i2c_smbus_read_word_swapped(client, DS620_REG_CONF);
        if (res < 0)
                return res;

        new_conf = conf = res;
        new_conf &= ~attr->index;
        if (conf != new_conf) {
                res = i2c_smbus_write_word_swapped(client, DS620_REG_CONF,
                                                   new_conf);
                if (res < 0)
                        return res;
        }

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

static SENSOR_DEVICE_ATTR_RO(temp1_input, temp, 0);
static SENSOR_DEVICE_ATTR_RW(temp1_min, temp, 1);
static SENSOR_DEVICE_ATTR_RW(temp1_max, temp, 2);
static SENSOR_DEVICE_ATTR_RO(temp1_min_alarm, alarm, DS620_REG_CONFIG_TLF);
static SENSOR_DEVICE_ATTR_RO(temp1_max_alarm, alarm, DS620_REG_CONFIG_THF);

static struct attribute *ds620_attrs[] = {
        &sensor_dev_attr_temp1_input.dev_attr.attr,
        &sensor_dev_attr_temp1_min.dev_attr.attr,
        &sensor_dev_attr_temp1_max.dev_attr.attr,
        &sensor_dev_attr_temp1_min_alarm.dev_attr.attr,
        &sensor_dev_attr_temp1_max_alarm.dev_attr.attr,
        NULL
};

ATTRIBUTE_GROUPS(ds620);

static int ds620_probe(struct i2c_client *client)
{
        struct device *dev = &client->dev;
        struct device *hwmon_dev;
        struct ds620_data *data;

        data = devm_kzalloc(dev, sizeof(struct ds620_data), GFP_KERNEL);
        if (!data)
                return -ENOMEM;

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

        /* Initialize the DS620 chip */
        ds620_init_client(client);

        hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name,
                                                           data, ds620_groups);
        return PTR_ERR_OR_ZERO(hwmon_dev);
}

static const struct i2c_device_id ds620_id[] = {
        {"ds620"},
        {}
};

MODULE_DEVICE_TABLE(i2c, ds620_id);

/* This is the driver that will be inserted */
static struct i2c_driver ds620_driver = {
        .driver = {
                   .name = "ds620",
        },
        .probe = ds620_probe,
        .id_table = ds620_id,
};

module_i2c_driver(ds620_driver);

MODULE_AUTHOR("Roland Stigge <stigge@antcom.de>");
MODULE_DESCRIPTION("DS620 driver");
MODULE_LICENSE("GPL");