// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Driver for TI ADC128D818 System Monitor with Temperature Sensor
 *
 * Copyright (c) 2014 Guenter Roeck
 *
 * Derived from lm80.c
 * Copyright (C) 1998, 1999  Frodo Looijaard <frodol@dds.nl>
 *                           and Philip Edelbrock <phil@netroedge.com>
 */

#include <linux/module.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/regulator/consumer.h>
#include <linux/mutex.h>
#include <linux/bitops.h>
#include <linux/of.h>

/* Addresses to scan
 * The chip also supports addresses 0x35..0x37. Don't scan those addresses
 * since they are also used by some EEPROMs, which may result in false
 * positives.
 */
static const unsigned short normal_i2c[] = {
        0x1d, 0x1e, 0x1f, 0x2d, 0x2e, 0x2f, I2C_CLIENT_END };

/* registers */
#define ADC128_REG_IN_MAX(nr)           (0x2a + (nr) * 2)
#define ADC128_REG_IN_MIN(nr)           (0x2b + (nr) * 2)
#define ADC128_REG_IN(nr)               (0x20 + (nr))

#define ADC128_REG_TEMP                 0x27
#define ADC128_REG_TEMP_MAX             0x38
#define ADC128_REG_TEMP_HYST            0x39

#define ADC128_REG_CONFIG               0x00
#define ADC128_REG_ALARM                0x01
#define ADC128_REG_MASK                 0x03
#define ADC128_REG_CONV_RATE            0x07
#define ADC128_REG_ONESHOT              0x09
#define ADC128_REG_SHUTDOWN             0x0a
#define ADC128_REG_CONFIG_ADV           0x0b
#define ADC128_REG_BUSY_STATUS          0x0c

#define ADC128_REG_MAN_ID               0x3e
#define ADC128_REG_DEV_ID               0x3f

/* No. of voltage entries in adc128_attrs */
#define ADC128_ATTR_NUM_VOLT            (8 * 4)

/* Voltage inputs visible per operation mode */
static const u8 num_inputs[] = { 7, 8, 4, 6 };

struct adc128_data {
        struct i2c_client *client;
        int vref;               /* Reference voltage in mV */
        struct mutex update_lock;
        u8 mode;                /* Operation mode */
        bool valid;             /* true if following fields are valid */
        unsigned long last_updated;     /* In jiffies */

        u16 in[3][8];           /* Register value, normalized to 12 bit
                                 * 0: input voltage
                                 * 1: min limit
                                 * 2: max limit
                                 */
        s16 temp[3];            /* Register value, normalized to 9 bit
                                 * 0: sensor 1: limit 2: hyst
                                 */
        u8 alarms;              /* alarm register value */
};

static struct adc128_data *adc128_update_device(struct device *dev)
{
        struct adc128_data *data = dev_get_drvdata(dev);
        struct i2c_client *client = data->client;
        struct adc128_data *ret = data;
        int i, rv;

        mutex_lock(&data->update_lock);

        if (time_after(jiffies, data->last_updated + HZ) || !data->valid) {
                for (i = 0; i < num_inputs[data->mode]; i++) {
                        rv = i2c_smbus_read_word_swapped(client,
                                                         ADC128_REG_IN(i));
                        if (rv < 0)
                                goto abort;
                        data->in[0][i] = rv >> 4;

                        rv = i2c_smbus_read_byte_data(client,
                                                      ADC128_REG_IN_MIN(i));
                        if (rv < 0)
                                goto abort;
                        data->in[1][i] = rv << 4;

                        rv = i2c_smbus_read_byte_data(client,
                                                      ADC128_REG_IN_MAX(i));
                        if (rv < 0)
                                goto abort;
                        data->in[2][i] = rv << 4;
                }

                if (data->mode != 1) {
                        rv = i2c_smbus_read_word_swapped(client,
                                                         ADC128_REG_TEMP);
                        if (rv < 0)
                                goto abort;
                        data->temp[0] = rv >> 7;

                        rv = i2c_smbus_read_byte_data(client,
                                                      ADC128_REG_TEMP_MAX);
                        if (rv < 0)
                                goto abort;
                        data->temp[1] = rv << 1;

                        rv = i2c_smbus_read_byte_data(client,
                                                      ADC128_REG_TEMP_HYST);
                        if (rv < 0)
                                goto abort;
                        data->temp[2] = rv << 1;
                }

                rv = i2c_smbus_read_byte_data(client, ADC128_REG_ALARM);
                if (rv < 0)
                        goto abort;
                data->alarms |= rv;

                data->last_updated = jiffies;
                data->valid = true;
        }
        goto done;

abort:
        ret = ERR_PTR(rv);
        data->valid = false;
done:
        mutex_unlock(&data->update_lock);
        return ret;
}

static ssize_t adc128_in_show(struct device *dev,
                              struct device_attribute *attr, char *buf)
{
        struct adc128_data *data = adc128_update_device(dev);
        int index = to_sensor_dev_attr_2(attr)->index;
        int nr = to_sensor_dev_attr_2(attr)->nr;
        int val;

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

        val = DIV_ROUND_CLOSEST(data->in[index][nr] * data->vref, 4095);
        return sprintf(buf, "%d\n", val);
}

static ssize_t adc128_in_store(struct device *dev,
                               struct device_attribute *attr, const char *buf,
                               size_t count)
{
        struct adc128_data *data = dev_get_drvdata(dev);
        int index = to_sensor_dev_attr_2(attr)->index;
        int nr = to_sensor_dev_attr_2(attr)->nr;
        u8 reg, regval;
        long val;
        int err;

        err = kstrtol(buf, 10, &val);
        if (err < 0)
                return err;

        mutex_lock(&data->update_lock);
        /* 10 mV LSB on limit registers */
        regval = DIV_ROUND_CLOSEST(clamp_val(val, 0, 2550), 10);
        data->in[index][nr] = regval << 4;
        reg = index == 1 ? ADC128_REG_IN_MIN(nr) : ADC128_REG_IN_MAX(nr);
        i2c_smbus_write_byte_data(data->client, reg, regval);
        mutex_unlock(&data->update_lock);

        return count;
}

static ssize_t adc128_temp_show(struct device *dev,
                                struct device_attribute *attr, char *buf)
{
        struct adc128_data *data = adc128_update_device(dev);
        int index = to_sensor_dev_attr(attr)->index;
        int temp;

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

        temp = sign_extend32(data->temp[index], 8);
        return sprintf(buf, "%d\n", temp * 500);/* 0.5 degrees C resolution */
}

static ssize_t adc128_temp_store(struct device *dev,
                                 struct device_attribute *attr,
                                 const char *buf, size_t count)
{
        struct adc128_data *data = dev_get_drvdata(dev);
        int index = to_sensor_dev_attr(attr)->index;
        long val;
        int err;
        s8 regval;

        err = kstrtol(buf, 10, &val);
        if (err < 0)
                return err;

        mutex_lock(&data->update_lock);
        regval = DIV_ROUND_CLOSEST(clamp_val(val, -128000, 127000), 1000);
        data->temp[index] = regval << 1;
        i2c_smbus_write_byte_data(data->client,
                                  index == 1 ? ADC128_REG_TEMP_MAX
                                             : ADC128_REG_TEMP_HYST,
                                  regval);
        mutex_unlock(&data->update_lock);

        return count;
}

static ssize_t adc128_alarm_show(struct device *dev,
                                 struct device_attribute *attr, char *buf)
{
        struct adc128_data *data = adc128_update_device(dev);
        int mask = 1 << to_sensor_dev_attr(attr)->index;
        u8 alarms;

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

        /*
         * Clear an alarm after reporting it to user space. If it is still
         * active, the next update sequence will set the alarm bit again.
         */
        alarms = data->alarms;
        data->alarms &= ~mask;

        return sprintf(buf, "%u\n", !!(alarms & mask));
}

static umode_t adc128_is_visible(struct kobject *kobj,
                                 struct attribute *attr, int index)
{
        struct device *dev = kobj_to_dev(kobj);
        struct adc128_data *data = dev_get_drvdata(dev);

        if (index < ADC128_ATTR_NUM_VOLT) {
                /* Voltage, visible according to num_inputs[] */
                if (index >= num_inputs[data->mode] * 4)
                        return 0;
        } else {
                /* Temperature, visible if not in mode 1 */
                if (data->mode == 1)
                        return 0;
        }

        return attr->mode;
}

static SENSOR_DEVICE_ATTR_2_RO(in0_input, adc128_in, 0, 0);
static SENSOR_DEVICE_ATTR_2_RW(in0_min, adc128_in, 0, 1);
static SENSOR_DEVICE_ATTR_2_RW(in0_max, adc128_in, 0, 2);

static SENSOR_DEVICE_ATTR_2_RO(in1_input, adc128_in, 1, 0);
static SENSOR_DEVICE_ATTR_2_RW(in1_min, adc128_in, 1, 1);
static SENSOR_DEVICE_ATTR_2_RW(in1_max, adc128_in, 1, 2);

static SENSOR_DEVICE_ATTR_2_RO(in2_input, adc128_in, 2, 0);
static SENSOR_DEVICE_ATTR_2_RW(in2_min, adc128_in, 2, 1);
static SENSOR_DEVICE_ATTR_2_RW(in2_max, adc128_in, 2, 2);

static SENSOR_DEVICE_ATTR_2_RO(in3_input, adc128_in, 3, 0);
static SENSOR_DEVICE_ATTR_2_RW(in3_min, adc128_in, 3, 1);
static SENSOR_DEVICE_ATTR_2_RW(in3_max, adc128_in, 3, 2);

static SENSOR_DEVICE_ATTR_2_RO(in4_input, adc128_in, 4, 0);
static SENSOR_DEVICE_ATTR_2_RW(in4_min, adc128_in, 4, 1);
static SENSOR_DEVICE_ATTR_2_RW(in4_max, adc128_in, 4, 2);

static SENSOR_DEVICE_ATTR_2_RO(in5_input, adc128_in, 5, 0);
static SENSOR_DEVICE_ATTR_2_RW(in5_min, adc128_in, 5, 1);
static SENSOR_DEVICE_ATTR_2_RW(in5_max, adc128_in, 5, 2);

static SENSOR_DEVICE_ATTR_2_RO(in6_input, adc128_in, 6, 0);
static SENSOR_DEVICE_ATTR_2_RW(in6_min, adc128_in, 6, 1);
static SENSOR_DEVICE_ATTR_2_RW(in6_max, adc128_in, 6, 2);

static SENSOR_DEVICE_ATTR_2_RO(in7_input, adc128_in, 7, 0);
static SENSOR_DEVICE_ATTR_2_RW(in7_min, adc128_in, 7, 1);
static SENSOR_DEVICE_ATTR_2_RW(in7_max, adc128_in, 7, 2);

static SENSOR_DEVICE_ATTR_RO(temp1_input, adc128_temp, 0);
static SENSOR_DEVICE_ATTR_RW(temp1_max, adc128_temp, 1);
static SENSOR_DEVICE_ATTR_RW(temp1_max_hyst, adc128_temp, 2);

static SENSOR_DEVICE_ATTR_RO(in0_alarm, adc128_alarm, 0);
static SENSOR_DEVICE_ATTR_RO(in1_alarm, adc128_alarm, 1);
static SENSOR_DEVICE_ATTR_RO(in2_alarm, adc128_alarm, 2);
static SENSOR_DEVICE_ATTR_RO(in3_alarm, adc128_alarm, 3);
static SENSOR_DEVICE_ATTR_RO(in4_alarm, adc128_alarm, 4);
static SENSOR_DEVICE_ATTR_RO(in5_alarm, adc128_alarm, 5);
static SENSOR_DEVICE_ATTR_RO(in6_alarm, adc128_alarm, 6);
static SENSOR_DEVICE_ATTR_RO(in7_alarm, adc128_alarm, 7);
static SENSOR_DEVICE_ATTR_RO(temp1_max_alarm, adc128_alarm, 7);

static struct attribute *adc128_attrs[] = {
        &sensor_dev_attr_in0_alarm.dev_attr.attr,
        &sensor_dev_attr_in0_input.dev_attr.attr,
        &sensor_dev_attr_in0_max.dev_attr.attr,
        &sensor_dev_attr_in0_min.dev_attr.attr,
        &sensor_dev_attr_in1_alarm.dev_attr.attr,
        &sensor_dev_attr_in1_input.dev_attr.attr,
        &sensor_dev_attr_in1_max.dev_attr.attr,
        &sensor_dev_attr_in1_min.dev_attr.attr,
        &sensor_dev_attr_in2_alarm.dev_attr.attr,
        &sensor_dev_attr_in2_input.dev_attr.attr,
        &sensor_dev_attr_in2_max.dev_attr.attr,
        &sensor_dev_attr_in2_min.dev_attr.attr,
        &sensor_dev_attr_in3_alarm.dev_attr.attr,
        &sensor_dev_attr_in3_input.dev_attr.attr,
        &sensor_dev_attr_in3_max.dev_attr.attr,
        &sensor_dev_attr_in3_min.dev_attr.attr,
        &sensor_dev_attr_in4_alarm.dev_attr.attr,
        &sensor_dev_attr_in4_input.dev_attr.attr,
        &sensor_dev_attr_in4_max.dev_attr.attr,
        &sensor_dev_attr_in4_min.dev_attr.attr,
        &sensor_dev_attr_in5_alarm.dev_attr.attr,
        &sensor_dev_attr_in5_input.dev_attr.attr,
        &sensor_dev_attr_in5_max.dev_attr.attr,
        &sensor_dev_attr_in5_min.dev_attr.attr,
        &sensor_dev_attr_in6_alarm.dev_attr.attr,
        &sensor_dev_attr_in6_input.dev_attr.attr,
        &sensor_dev_attr_in6_max.dev_attr.attr,
        &sensor_dev_attr_in6_min.dev_attr.attr,
        &sensor_dev_attr_in7_alarm.dev_attr.attr,
        &sensor_dev_attr_in7_input.dev_attr.attr,
        &sensor_dev_attr_in7_max.dev_attr.attr,
        &sensor_dev_attr_in7_min.dev_attr.attr,
        &sensor_dev_attr_temp1_input.dev_attr.attr,
        &sensor_dev_attr_temp1_max.dev_attr.attr,
        &sensor_dev_attr_temp1_max_alarm.dev_attr.attr,
        &sensor_dev_attr_temp1_max_hyst.dev_attr.attr,
        NULL
};

static const struct attribute_group adc128_group = {
        .attrs = adc128_attrs,
        .is_visible = adc128_is_visible,
};
__ATTRIBUTE_GROUPS(adc128);

static int adc128_detect(struct i2c_client *client, struct i2c_board_info *info)
{
        int man_id, dev_id;

        if (!i2c_check_functionality(client->adapter,
                                     I2C_FUNC_SMBUS_BYTE_DATA |
                                     I2C_FUNC_SMBUS_WORD_DATA))
                return -ENODEV;

        man_id = i2c_smbus_read_byte_data(client, ADC128_REG_MAN_ID);
        dev_id = i2c_smbus_read_byte_data(client, ADC128_REG_DEV_ID);
        if (man_id != 0x01 || dev_id != 0x09)
                return -ENODEV;

        /* Check unused bits for confirmation */
        if (i2c_smbus_read_byte_data(client, ADC128_REG_CONFIG) & 0xf4)
                return -ENODEV;
        if (i2c_smbus_read_byte_data(client, ADC128_REG_CONV_RATE) & 0xfe)
                return -ENODEV;
        if (i2c_smbus_read_byte_data(client, ADC128_REG_ONESHOT) & 0xfe)
                return -ENODEV;
        if (i2c_smbus_read_byte_data(client, ADC128_REG_SHUTDOWN) & 0xfe)
                return -ENODEV;
        if (i2c_smbus_read_byte_data(client, ADC128_REG_CONFIG_ADV) & 0xf8)
                return -ENODEV;
        if (i2c_smbus_read_byte_data(client, ADC128_REG_BUSY_STATUS) & 0xfc)
                return -ENODEV;

        strscpy(info->type, "adc128d818", I2C_NAME_SIZE);

        return 0;
}

static int adc128_init_client(struct adc128_data *data, bool external_vref)
{
        struct i2c_client *client = data->client;
        int err;
        u8 regval = 0x0;

        /*
         * Reset chip to defaults.
         * This makes most other initializations unnecessary.
         */
        err = i2c_smbus_write_byte_data(client, ADC128_REG_CONFIG, 0x80);
        if (err)
                return err;

        /* Set operation mode, if non-default */
        if (data->mode != 0)
                regval |= data->mode << 1;

        /* If external vref is selected, configure the chip to use it */
        if (external_vref)
                regval |= 0x01;

        /* Write advanced configuration register */
        if (regval != 0x0) {
                err = i2c_smbus_write_byte_data(client, ADC128_REG_CONFIG_ADV,
                                                regval);
                if (err)
                        return err;
        }

        /* Start monitoring */
        err = i2c_smbus_write_byte_data(client, ADC128_REG_CONFIG, 0x01);
        if (err)
                return err;

        return 0;
}

static int adc128_probe(struct i2c_client *client)
{
        struct device *dev = &client->dev;
        struct device *hwmon_dev;
        struct adc128_data *data;
        bool external_vref;
        int err, vref;

        data = devm_kzalloc(dev, sizeof(struct adc128_data), GFP_KERNEL);
        if (!data)
                return -ENOMEM;

        /* vref is optional. If specified, is used as chip reference voltage */
        vref = devm_regulator_get_enable_read_voltage(dev, "vref");
        if (vref == -ENODEV) {
                external_vref = false;
                data->vref = 2560;      /* 2.56V, in mV */
        } else if (vref < 0) {
                return vref;
        } else {
                external_vref = true;
                data->vref = DIV_ROUND_CLOSEST(vref, 1000);
        }

        /* Operation mode is optional. If unspecified, keep current mode */
        if (of_property_read_u8(dev->of_node, "ti,mode", &data->mode) == 0) {
                if (data->mode > 3) {
                        dev_err(dev, "invalid operation mode %d\n",
                                data->mode);
                        return -EINVAL;
                }
        } else {
                err = i2c_smbus_read_byte_data(client, ADC128_REG_CONFIG_ADV);
                if (err < 0)
                        return err;
                data->mode = (err >> 1) & ADC128_REG_MASK;
        }

        data->client = client;
        i2c_set_clientdata(client, data);
        mutex_init(&data->update_lock);

        /* Initialize the chip */
        err = adc128_init_client(data, external_vref);
        if (err < 0)
                return err;

        hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name,
                                                           data, adc128_groups);

        return PTR_ERR_OR_ZERO(hwmon_dev);
}

static const struct i2c_device_id adc128_id[] = {
        { "adc128d818" },
        { }
};
MODULE_DEVICE_TABLE(i2c, adc128_id);

static const struct of_device_id __maybe_unused adc128_of_match[] = {
        { .compatible = "ti,adc128d818" },
        { },
};
MODULE_DEVICE_TABLE(of, adc128_of_match);

static struct i2c_driver adc128_driver = {
        .class          = I2C_CLASS_HWMON,
        .driver = {
                .name   = "adc128d818",
                .of_match_table = of_match_ptr(adc128_of_match),
        },
        .probe          = adc128_probe,
        .id_table       = adc128_id,
        .detect         = adc128_detect,
        .address_list   = normal_i2c,
};

module_i2c_driver(adc128_driver);

MODULE_AUTHOR("Guenter Roeck");
MODULE_DESCRIPTION("Driver for ADC128D818");
MODULE_LICENSE("GPL");