// SPDX-License-Identifier: GPL-2.0-only
/*
 * Driver for the Texas Instruments / Burr Brown INA209
 * Bidirectional Current/Power Monitor
 *
 * Copyright (C) 2012 Guenter Roeck <linux@roeck-us.net>
 *
 * Derived from Ira W. Snyder's original driver submission
 *      Copyright (C) 2008 Paul Hays <Paul.Hays@cattail.ca>
 *      Copyright (C) 2008-2009 Ira W. Snyder <iws@ovro.caltech.edu>
 *
 * Aligned with ina2xx driver
 *      Copyright (C) 2012 Lothar Felten <l-felten@ti.com>
 *      Thanks to Jan Volkering
 *
 * Datasheet:
 * https://www.ti.com/lit/gpn/ina209
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/err.h>
#include <linux/slab.h>
#include <linux/bug.h>
#include <linux/i2c.h>
#include <linux/hwmon.h>
#include <linux/hwmon-sysfs.h>

#include <linux/platform_data/ina2xx.h>

/* register definitions */
#define INA209_CONFIGURATION            0x00
#define INA209_STATUS                   0x01
#define INA209_STATUS_MASK              0x02
#define INA209_SHUNT_VOLTAGE            0x03
#define INA209_BUS_VOLTAGE              0x04
#define INA209_POWER                    0x05
#define INA209_CURRENT                  0x06
#define INA209_SHUNT_VOLTAGE_POS_PEAK   0x07
#define INA209_SHUNT_VOLTAGE_NEG_PEAK   0x08
#define INA209_BUS_VOLTAGE_MAX_PEAK     0x09
#define INA209_BUS_VOLTAGE_MIN_PEAK     0x0a
#define INA209_POWER_PEAK               0x0b
#define INA209_SHUNT_VOLTAGE_POS_WARN   0x0c
#define INA209_SHUNT_VOLTAGE_NEG_WARN   0x0d
#define INA209_POWER_WARN               0x0e
#define INA209_BUS_VOLTAGE_OVER_WARN    0x0f
#define INA209_BUS_VOLTAGE_UNDER_WARN   0x10
#define INA209_POWER_OVER_LIMIT         0x11
#define INA209_BUS_VOLTAGE_OVER_LIMIT   0x12
#define INA209_BUS_VOLTAGE_UNDER_LIMIT  0x13
#define INA209_CRITICAL_DAC_POS         0x14
#define INA209_CRITICAL_DAC_NEG         0x15
#define INA209_CALIBRATION              0x16

#define INA209_REGISTERS                0x17

#define INA209_CONFIG_DEFAULT           0x3c47  /* PGA=8, full range */
#define INA209_SHUNT_DEFAULT            10000   /* uOhm */

struct ina209_data {
        struct i2c_client *client;

        struct mutex update_lock;
        bool valid;
        unsigned long last_updated;     /* in jiffies */

        u16 regs[INA209_REGISTERS];     /* All chip registers */

        u16 config_orig;                /* Original configuration */
        u16 calibration_orig;           /* Original calibration */
        u16 update_interval;
};

static struct ina209_data *ina209_update_device(struct device *dev)
{
        struct ina209_data *data = dev_get_drvdata(dev);
        struct i2c_client *client = data->client;
        struct ina209_data *ret = data;
        s32 val;
        int i;

        mutex_lock(&data->update_lock);

        if (!data->valid ||
            time_after(jiffies, data->last_updated + data->update_interval)) {
                for (i = 0; i < ARRAY_SIZE(data->regs); i++) {
                        val = i2c_smbus_read_word_swapped(client, i);
                        if (val < 0) {
                                ret = ERR_PTR(val);
                                goto abort;
                        }
                        data->regs[i] = val;
                }
                data->last_updated = jiffies;
                data->valid = true;
        }
abort:
        mutex_unlock(&data->update_lock);
        return ret;
}

/*
 * Read a value from a device register and convert it to the
 * appropriate sysfs units
 */
static long ina209_from_reg(const u8 reg, const u16 val)
{
        switch (reg) {
        case INA209_SHUNT_VOLTAGE:
        case INA209_SHUNT_VOLTAGE_POS_PEAK:
        case INA209_SHUNT_VOLTAGE_NEG_PEAK:
        case INA209_SHUNT_VOLTAGE_POS_WARN:
        case INA209_SHUNT_VOLTAGE_NEG_WARN:
                /* LSB=10 uV. Convert to mV. */
                return DIV_ROUND_CLOSEST((s16)val, 100);

        case INA209_BUS_VOLTAGE:
        case INA209_BUS_VOLTAGE_MAX_PEAK:
        case INA209_BUS_VOLTAGE_MIN_PEAK:
        case INA209_BUS_VOLTAGE_OVER_WARN:
        case INA209_BUS_VOLTAGE_UNDER_WARN:
        case INA209_BUS_VOLTAGE_OVER_LIMIT:
        case INA209_BUS_VOLTAGE_UNDER_LIMIT:
                /* LSB=4 mV, last 3 bits unused */
                return (val >> 3) * 4;

        case INA209_CRITICAL_DAC_POS:
                /* LSB=1 mV, in the upper 8 bits */
                return val >> 8;

        case INA209_CRITICAL_DAC_NEG:
                /* LSB=1 mV, in the upper 8 bits */
                return -1 * (val >> 8);

        case INA209_POWER:
        case INA209_POWER_PEAK:
        case INA209_POWER_WARN:
        case INA209_POWER_OVER_LIMIT:
                /* LSB=20 mW. Convert to uW */
                return val * 20 * 1000L;

        case INA209_CURRENT:
                /* LSB=1 mA (selected). Is in mA */
                return (s16)val;
        }

        /* programmer goofed */
        WARN_ON_ONCE(1);
        return 0;
}

/*
 * Take a value and convert it to register format, clamping the value
 * to the appropriate range.
 */
static int ina209_to_reg(u8 reg, u16 old, long val)
{
        switch (reg) {
        case INA209_SHUNT_VOLTAGE_POS_WARN:
        case INA209_SHUNT_VOLTAGE_NEG_WARN:
                /* Limit to +- 320 mV, 10 uV LSB */
                return clamp_val(val, -320, 320) * 100;

        case INA209_BUS_VOLTAGE_OVER_WARN:
        case INA209_BUS_VOLTAGE_UNDER_WARN:
        case INA209_BUS_VOLTAGE_OVER_LIMIT:
        case INA209_BUS_VOLTAGE_UNDER_LIMIT:
                /*
                 * Limit to 0-32000 mV, 4 mV LSB
                 *
                 * The last three bits aren't part of the value, but we'll
                 * preserve them in their original state.
                 */
                return (DIV_ROUND_CLOSEST(clamp_val(val, 0, 32000), 4) << 3)
                  | (old & 0x7);

        case INA209_CRITICAL_DAC_NEG:
                /*
                 * Limit to -255-0 mV, 1 mV LSB
                 * Convert the value to a positive value for the register
                 *
                 * The value lives in the top 8 bits only, be careful
                 * and keep original value of other bits.
                 */
                return (clamp_val(-val, 0, 255) << 8) | (old & 0xff);

        case INA209_CRITICAL_DAC_POS:
                /*
                 * Limit to 0-255 mV, 1 mV LSB
                 *
                 * The value lives in the top 8 bits only, be careful
                 * and keep original value of other bits.
                 */
                return (clamp_val(val, 0, 255) << 8) | (old & 0xff);

        case INA209_POWER_WARN:
        case INA209_POWER_OVER_LIMIT:
                /* 20 mW LSB */
                return DIV_ROUND_CLOSEST(val, 20 * 1000);
        }

        /* Other registers are read-only, return access error */
        return -EACCES;
}

static int ina209_interval_from_reg(u16 reg)
{
        return 68 >> (15 - ((reg >> 3) & 0x0f));
}

static u16 ina209_reg_from_interval(u16 config, long interval)
{
        int i, adc;

        if (interval <= 0) {
                adc = 8;
        } else {
                adc = 15;
                for (i = 34 + 34 / 2; i; i >>= 1) {
                        if (i < interval)
                                break;
                        adc--;
                }
        }
        return (config & 0xf807) | (adc << 3) | (adc << 7);
}

static ssize_t ina209_interval_store(struct device *dev,
                                     struct device_attribute *da,
                                     const char *buf, size_t count)
{
        struct ina209_data *data = ina209_update_device(dev);
        long val;
        u16 regval;
        int ret;

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

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

        mutex_lock(&data->update_lock);
        regval = ina209_reg_from_interval(data->regs[INA209_CONFIGURATION],
                                          val);
        i2c_smbus_write_word_swapped(data->client, INA209_CONFIGURATION,
                                     regval);
        data->regs[INA209_CONFIGURATION] = regval;
        data->update_interval = ina209_interval_from_reg(regval);
        mutex_unlock(&data->update_lock);
        return count;
}

static ssize_t ina209_interval_show(struct device *dev,
                                    struct device_attribute *da, char *buf)
{
        struct ina209_data *data = dev_get_drvdata(dev);

        return sysfs_emit(buf, "%d\n", data->update_interval);
}

/*
 * History is reset by writing 1 into bit 0 of the respective peak register.
 * Since more than one peak register may be affected by the scope of a
 * reset_history attribute write, use a bit mask in attr->index to identify
 * which registers are affected.
 */
static u16 ina209_reset_history_regs[] = {
        INA209_SHUNT_VOLTAGE_POS_PEAK,
        INA209_SHUNT_VOLTAGE_NEG_PEAK,
        INA209_BUS_VOLTAGE_MAX_PEAK,
        INA209_BUS_VOLTAGE_MIN_PEAK,
        INA209_POWER_PEAK
};

static ssize_t ina209_history_store(struct device *dev,
                                    struct device_attribute *da,
                                    const char *buf, size_t count)
{
        struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
        struct ina209_data *data = dev_get_drvdata(dev);
        struct i2c_client *client = data->client;
        u32 mask = attr->index;
        long val;
        int i, ret;

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

        mutex_lock(&data->update_lock);
        for (i = 0; i < ARRAY_SIZE(ina209_reset_history_regs); i++) {
                if (mask & (1 << i))
                        i2c_smbus_write_word_swapped(client,
                                        ina209_reset_history_regs[i], 1);
        }
        data->valid = false;
        mutex_unlock(&data->update_lock);
        return count;
}

static ssize_t ina209_value_store(struct device *dev,
                                  struct device_attribute *da,
                                  const char *buf, size_t count)
{
        struct ina209_data *data = ina209_update_device(dev);
        struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
        int reg = attr->index;
        long val;
        int ret;

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

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

        mutex_lock(&data->update_lock);
        ret = ina209_to_reg(reg, data->regs[reg], val);
        if (ret < 0) {
                count = ret;
                goto abort;
        }
        i2c_smbus_write_word_swapped(data->client, reg, ret);
        data->regs[reg] = ret;
abort:
        mutex_unlock(&data->update_lock);
        return count;
}

static ssize_t ina209_value_show(struct device *dev,
                                 struct device_attribute *da, char *buf)
{
        struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
        struct ina209_data *data = ina209_update_device(dev);
        long val;

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

        val = ina209_from_reg(attr->index, data->regs[attr->index]);
        return sysfs_emit(buf, "%ld\n", val);
}

static ssize_t ina209_alarm_show(struct device *dev,
                                 struct device_attribute *da, char *buf)
{
        struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
        struct ina209_data *data = ina209_update_device(dev);
        const unsigned int mask = attr->index;
        u16 status;

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

        status = data->regs[INA209_STATUS];

        /*
         * All alarms are in the INA209_STATUS register. To avoid a long
         * switch statement, the mask is passed in attr->index
         */
        return sysfs_emit(buf, "%u\n", !!(status & mask));
}

/* Shunt voltage, history, limits, alarms */
static SENSOR_DEVICE_ATTR_RO(in0_input, ina209_value, INA209_SHUNT_VOLTAGE);
static SENSOR_DEVICE_ATTR_RO(in0_input_highest, ina209_value,
                             INA209_SHUNT_VOLTAGE_POS_PEAK);
static SENSOR_DEVICE_ATTR_RO(in0_input_lowest, ina209_value,
                             INA209_SHUNT_VOLTAGE_NEG_PEAK);
static SENSOR_DEVICE_ATTR_WO(in0_reset_history, ina209_history,
                             (1 << 0) | (1 << 1));
static SENSOR_DEVICE_ATTR_RW(in0_max, ina209_value,
                             INA209_SHUNT_VOLTAGE_POS_WARN);
static SENSOR_DEVICE_ATTR_RW(in0_min, ina209_value,
                             INA209_SHUNT_VOLTAGE_NEG_WARN);
static SENSOR_DEVICE_ATTR_RW(in0_crit_max, ina209_value,
                             INA209_CRITICAL_DAC_POS);
static SENSOR_DEVICE_ATTR_RW(in0_crit_min, ina209_value,
                             INA209_CRITICAL_DAC_NEG);

static SENSOR_DEVICE_ATTR_RO(in0_min_alarm, ina209_alarm, 1 << 11);
static SENSOR_DEVICE_ATTR_RO(in0_max_alarm, ina209_alarm, 1 << 12);
static SENSOR_DEVICE_ATTR_RO(in0_crit_min_alarm, ina209_alarm, 1 << 6);
static SENSOR_DEVICE_ATTR_RO(in0_crit_max_alarm, ina209_alarm, 1 << 7);

/* Bus voltage, history, limits, alarms */
static SENSOR_DEVICE_ATTR_RO(in1_input, ina209_value, INA209_BUS_VOLTAGE);
static SENSOR_DEVICE_ATTR_RO(in1_input_highest, ina209_value,
                             INA209_BUS_VOLTAGE_MAX_PEAK);
static SENSOR_DEVICE_ATTR_RO(in1_input_lowest, ina209_value,
                             INA209_BUS_VOLTAGE_MIN_PEAK);
static SENSOR_DEVICE_ATTR_WO(in1_reset_history, ina209_history,
                             (1 << 2) | (1 << 3));
static SENSOR_DEVICE_ATTR_RW(in1_max, ina209_value,
                             INA209_BUS_VOLTAGE_OVER_WARN);
static SENSOR_DEVICE_ATTR_RW(in1_min, ina209_value,
                             INA209_BUS_VOLTAGE_UNDER_WARN);
static SENSOR_DEVICE_ATTR_RW(in1_crit_max, ina209_value,
                             INA209_BUS_VOLTAGE_OVER_LIMIT);
static SENSOR_DEVICE_ATTR_RW(in1_crit_min, ina209_value,
                             INA209_BUS_VOLTAGE_UNDER_LIMIT);

static SENSOR_DEVICE_ATTR_RO(in1_min_alarm, ina209_alarm, 1 << 14);
static SENSOR_DEVICE_ATTR_RO(in1_max_alarm, ina209_alarm, 1 << 15);
static SENSOR_DEVICE_ATTR_RO(in1_crit_min_alarm, ina209_alarm, 1 << 9);
static SENSOR_DEVICE_ATTR_RO(in1_crit_max_alarm, ina209_alarm, 1 << 10);

/* Power */
static SENSOR_DEVICE_ATTR_RO(power1_input, ina209_value, INA209_POWER);
static SENSOR_DEVICE_ATTR_RO(power1_input_highest, ina209_value,
                             INA209_POWER_PEAK);
static SENSOR_DEVICE_ATTR_WO(power1_reset_history, ina209_history, 1 << 4);
static SENSOR_DEVICE_ATTR_RW(power1_max, ina209_value, INA209_POWER_WARN);
static SENSOR_DEVICE_ATTR_RW(power1_crit, ina209_value,
                             INA209_POWER_OVER_LIMIT);

static SENSOR_DEVICE_ATTR_RO(power1_max_alarm, ina209_alarm, 1 << 13);
static SENSOR_DEVICE_ATTR_RO(power1_crit_alarm, ina209_alarm, 1 << 8);

/* Current */
static SENSOR_DEVICE_ATTR_RO(curr1_input, ina209_value, INA209_CURRENT);

static SENSOR_DEVICE_ATTR_RW(update_interval, ina209_interval, 0);

/*
 * Finally, construct an array of pointers to members of the above objects,
 * as required for sysfs_create_group()
 */
static struct attribute *ina209_attrs[] = {
        &sensor_dev_attr_in0_input.dev_attr.attr,
        &sensor_dev_attr_in0_input_highest.dev_attr.attr,
        &sensor_dev_attr_in0_input_lowest.dev_attr.attr,
        &sensor_dev_attr_in0_reset_history.dev_attr.attr,
        &sensor_dev_attr_in0_max.dev_attr.attr,
        &sensor_dev_attr_in0_min.dev_attr.attr,
        &sensor_dev_attr_in0_crit_max.dev_attr.attr,
        &sensor_dev_attr_in0_crit_min.dev_attr.attr,
        &sensor_dev_attr_in0_max_alarm.dev_attr.attr,
        &sensor_dev_attr_in0_min_alarm.dev_attr.attr,
        &sensor_dev_attr_in0_crit_max_alarm.dev_attr.attr,
        &sensor_dev_attr_in0_crit_min_alarm.dev_attr.attr,

        &sensor_dev_attr_in1_input.dev_attr.attr,
        &sensor_dev_attr_in1_input_highest.dev_attr.attr,
        &sensor_dev_attr_in1_input_lowest.dev_attr.attr,
        &sensor_dev_attr_in1_reset_history.dev_attr.attr,
        &sensor_dev_attr_in1_max.dev_attr.attr,
        &sensor_dev_attr_in1_min.dev_attr.attr,
        &sensor_dev_attr_in1_crit_max.dev_attr.attr,
        &sensor_dev_attr_in1_crit_min.dev_attr.attr,
        &sensor_dev_attr_in1_max_alarm.dev_attr.attr,
        &sensor_dev_attr_in1_min_alarm.dev_attr.attr,
        &sensor_dev_attr_in1_crit_max_alarm.dev_attr.attr,
        &sensor_dev_attr_in1_crit_min_alarm.dev_attr.attr,

        &sensor_dev_attr_power1_input.dev_attr.attr,
        &sensor_dev_attr_power1_input_highest.dev_attr.attr,
        &sensor_dev_attr_power1_reset_history.dev_attr.attr,
        &sensor_dev_attr_power1_max.dev_attr.attr,
        &sensor_dev_attr_power1_crit.dev_attr.attr,
        &sensor_dev_attr_power1_max_alarm.dev_attr.attr,
        &sensor_dev_attr_power1_crit_alarm.dev_attr.attr,

        &sensor_dev_attr_curr1_input.dev_attr.attr,

        &sensor_dev_attr_update_interval.dev_attr.attr,

        NULL,
};
ATTRIBUTE_GROUPS(ina209);

static void ina209_restore_conf(struct i2c_client *client,
                                struct ina209_data *data)
{
        /* Restore initial configuration */
        i2c_smbus_write_word_swapped(client, INA209_CONFIGURATION,
                                     data->config_orig);
        i2c_smbus_write_word_swapped(client, INA209_CALIBRATION,
                                     data->calibration_orig);
}

static int ina209_init_client(struct i2c_client *client,
                              struct ina209_data *data)
{
        struct ina2xx_platform_data *pdata = dev_get_platdata(&client->dev);
        u32 shunt;
        int reg;

        reg = i2c_smbus_read_word_swapped(client, INA209_CALIBRATION);
        if (reg < 0)
                return reg;
        data->calibration_orig = reg;

        reg = i2c_smbus_read_word_swapped(client, INA209_CONFIGURATION);
        if (reg < 0)
                return reg;
        data->config_orig = reg;

        if (pdata) {
                if (pdata->shunt_uohms <= 0)
                        return -EINVAL;
                shunt = pdata->shunt_uohms;
        } else if (!of_property_read_u32(client->dev.of_node, "shunt-resistor",
                                         &shunt)) {
                if (shunt == 0)
                        return -EINVAL;
        } else {
                shunt = data->calibration_orig ?
                  40960000 / data->calibration_orig : INA209_SHUNT_DEFAULT;
        }

        i2c_smbus_write_word_swapped(client, INA209_CONFIGURATION,
                                     INA209_CONFIG_DEFAULT);
        data->update_interval = ina209_interval_from_reg(INA209_CONFIG_DEFAULT);

        /*
         * Calibrate current LSB to 1mA. Shunt is in uOhms.
         * See equation 13 in datasheet.
         */
        i2c_smbus_write_word_swapped(client, INA209_CALIBRATION,
                                     clamp_val(40960000 / shunt, 1, 65535));

        /* Clear status register */
        i2c_smbus_read_word_swapped(client, INA209_STATUS);

        return 0;
}

static int ina209_probe(struct i2c_client *client)
{
        struct i2c_adapter *adapter = client->adapter;
        struct ina209_data *data;
        struct device *hwmon_dev;
        int ret;

        if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_WORD_DATA))
                return -ENODEV;

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

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

        ret = ina209_init_client(client, data);
        if (ret)
                return ret;

        hwmon_dev = devm_hwmon_device_register_with_groups(&client->dev,
                                                           client->name,
                                                           data, ina209_groups);
        if (IS_ERR(hwmon_dev)) {
                ret = PTR_ERR(hwmon_dev);
                goto out_restore_conf;
        }

        return 0;

out_restore_conf:
        ina209_restore_conf(client, data);
        return ret;
}

static void ina209_remove(struct i2c_client *client)
{
        struct ina209_data *data = i2c_get_clientdata(client);

        ina209_restore_conf(client, data);
}

static const struct i2c_device_id ina209_id[] = {
        { "ina209" },
        { }
};
MODULE_DEVICE_TABLE(i2c, ina209_id);

static const struct of_device_id __maybe_unused ina209_of_match[] = {
        { .compatible = "ti,ina209" },
        { },
};
MODULE_DEVICE_TABLE(of, ina209_of_match);

/* This is the driver that will be inserted */
static struct i2c_driver ina209_driver = {
        .driver = {
                .name   = "ina209",
                .of_match_table = of_match_ptr(ina209_of_match),
        },
        .probe          = ina209_probe,
        .remove         = ina209_remove,
        .id_table       = ina209_id,
};

module_i2c_driver(ina209_driver);

MODULE_AUTHOR("Ira W. Snyder <iws@ovro.caltech.edu>, Paul Hays <Paul.Hays@cattail.ca>, Guenter Roeck <linux@roeck-us.net>");
MODULE_DESCRIPTION("INA209 driver");
MODULE_LICENSE("GPL");