// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * powr1220.c - Driver for the Lattice POWR1220 programmable power supply
 * and monitor. Users can read all ADC inputs along with their labels
 * using the sysfs nodes.
 *
 * Copyright (c) 2014 Echo360 https://www.echo360.com
 * Scott Kanowitz <skanowitz@echo360.com> <scott.kanowitz@gmail.com>
 */

#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/delay.h>

#define ADC_STEP_MV                     2
#define ADC_MAX_LOW_MEASUREMENT_MV      2000

enum powr1xxx_chips { powr1014, powr1220 };

enum powr1220_regs {
        VMON_STATUS0,
        VMON_STATUS1,
        VMON_STATUS2,
        OUTPUT_STATUS0,
        OUTPUT_STATUS1,
        OUTPUT_STATUS2,
        INPUT_STATUS,
        ADC_VALUE_LOW,
        ADC_VALUE_HIGH,
        ADC_MUX,
        UES_BYTE0,
        UES_BYTE1,
        UES_BYTE2,
        UES_BYTE3,
        GP_OUTPUT1,
        GP_OUTPUT2,
        GP_OUTPUT3,
        INPUT_VALUE,
        RESET,
        TRIM1_TRIM,
        TRIM2_TRIM,
        TRIM3_TRIM,
        TRIM4_TRIM,
        TRIM5_TRIM,
        TRIM6_TRIM,
        TRIM7_TRIM,
        TRIM8_TRIM,
        MAX_POWR1220_REGS
};

enum powr1220_adc_values {
        VMON1,
        VMON2,
        VMON3,
        VMON4,
        VMON5,
        VMON6,
        VMON7,
        VMON8,
        VMON9,
        VMON10,
        VMON11,
        VMON12,
        VCCA,
        VCCINP,
        MAX_POWR1220_ADC_VALUES
};

struct powr1220_data {
        struct i2c_client *client;
        u8 max_channels;
        bool adc_valid[MAX_POWR1220_ADC_VALUES];
         /* the next value is in jiffies */
        unsigned long adc_last_updated[MAX_POWR1220_ADC_VALUES];

        /* values */
        int adc_maxes[MAX_POWR1220_ADC_VALUES];
        int adc_values[MAX_POWR1220_ADC_VALUES];
};

static const char * const input_names[] = {
        [VMON1]    = "vmon1",
        [VMON2]    = "vmon2",
        [VMON3]    = "vmon3",
        [VMON4]    = "vmon4",
        [VMON5]    = "vmon5",
        [VMON6]    = "vmon6",
        [VMON7]    = "vmon7",
        [VMON8]    = "vmon8",
        [VMON9]    = "vmon9",
        [VMON10]   = "vmon10",
        [VMON11]   = "vmon11",
        [VMON12]   = "vmon12",
        [VCCA]     = "vcca",
        [VCCINP]   = "vccinp",
};

/* Reads the specified ADC channel */
static int powr1220_read_adc(struct device *dev, int ch_num)
{
        struct powr1220_data *data = dev_get_drvdata(dev);
        int reading;
        int result;
        int adc_range = 0;

        if (time_after(jiffies, data->adc_last_updated[ch_num] + HZ) ||
            !data->adc_valid[ch_num]) {
                /*
                 * figure out if we need to use the attenuator for
                 * high inputs or inputs that we don't yet have a measurement
                 * for. We dynamically set the attenuator depending on the
                 * max reading.
                 */
                if (data->adc_maxes[ch_num] > ADC_MAX_LOW_MEASUREMENT_MV ||
                    data->adc_maxes[ch_num] == 0)
                        adc_range = 1 << 4;

                /* set the attenuator and mux */
                result = i2c_smbus_write_byte_data(data->client, ADC_MUX,
                                                   adc_range | ch_num);
                if (result < 0)
                        return result;

                /*
                 * wait at least Tconvert time (200 us) for the
                 * conversion to complete
                 */
                udelay(200);

                /* get the ADC reading */
                result = i2c_smbus_read_byte_data(data->client, ADC_VALUE_LOW);
                if (result < 0)
                        return result;

                reading = result >> 4;

                /* get the upper half of the reading */
                result = i2c_smbus_read_byte_data(data->client, ADC_VALUE_HIGH);
                if (result < 0)
                        return result;

                reading |= result << 4;

                /* now convert the reading to a voltage */
                reading *= ADC_STEP_MV;
                data->adc_values[ch_num] = reading;
                data->adc_valid[ch_num] = true;
                data->adc_last_updated[ch_num] = jiffies;
                result = reading;

                if (reading > data->adc_maxes[ch_num])
                        data->adc_maxes[ch_num] = reading;
        } else {
                result = data->adc_values[ch_num];
        }
        return result;
}

static umode_t
powr1220_is_visible(const void *data, enum hwmon_sensor_types type, u32
                    attr, int channel)
{
        struct powr1220_data *chip_data = (struct powr1220_data *)data;

        if (channel >= chip_data->max_channels)
                return 0;

        switch (type) {
        case hwmon_in:
                switch (attr) {
                case hwmon_in_input:
                case hwmon_in_highest:
                case hwmon_in_label:
                        return 0444;
                default:
                        break;
                }
                break;
        default:
                break;
        }

        return 0;
}

static int
powr1220_read_string(struct device *dev, enum hwmon_sensor_types type, u32 attr,
                     int channel, const char **str)
{
        switch (type) {
        case hwmon_in:
                switch (attr) {
                case hwmon_in_label:
                        *str = input_names[channel];
                        return 0;
                default:
                        return -EOPNOTSUPP;
                }
                break;
        default:
                return -EOPNOTSUPP;
        }

        return -EOPNOTSUPP;
}

static int
powr1220_read(struct device *dev, enum hwmon_sensor_types type, u32
              attr, int channel, long *val)
{
        struct powr1220_data *data = dev_get_drvdata(dev);
        int ret;

        switch (type) {
        case hwmon_in:
                switch (attr) {
                case hwmon_in_input:
                        ret = powr1220_read_adc(dev, channel);
                        if (ret < 0)
                                return ret;
                        *val = ret;
                        break;
                case hwmon_in_highest:
                        *val = data->adc_maxes[channel];
                        break;
                default:
                        return -EOPNOTSUPP;
                }
                break;
        default:
                return -EOPNOTSUPP;
}

        return 0;
}

static const struct hwmon_channel_info * const powr1220_info[] = {
        HWMON_CHANNEL_INFO(in,
                           HWMON_I_INPUT | HWMON_I_HIGHEST | HWMON_I_LABEL,
                           HWMON_I_INPUT | HWMON_I_HIGHEST | HWMON_I_LABEL,
                           HWMON_I_INPUT | HWMON_I_HIGHEST | HWMON_I_LABEL,
                           HWMON_I_INPUT | HWMON_I_HIGHEST | HWMON_I_LABEL,
                           HWMON_I_INPUT | HWMON_I_HIGHEST | HWMON_I_LABEL,
                           HWMON_I_INPUT | HWMON_I_HIGHEST | HWMON_I_LABEL,
                           HWMON_I_INPUT | HWMON_I_HIGHEST | HWMON_I_LABEL,
                           HWMON_I_INPUT | HWMON_I_HIGHEST | HWMON_I_LABEL,
                           HWMON_I_INPUT | HWMON_I_HIGHEST | HWMON_I_LABEL,
                           HWMON_I_INPUT | HWMON_I_HIGHEST | HWMON_I_LABEL,
                           HWMON_I_INPUT | HWMON_I_HIGHEST | HWMON_I_LABEL,
                           HWMON_I_INPUT | HWMON_I_HIGHEST | HWMON_I_LABEL,
                           HWMON_I_INPUT | HWMON_I_HIGHEST | HWMON_I_LABEL,
                           HWMON_I_INPUT | HWMON_I_HIGHEST | HWMON_I_LABEL),

        NULL
};

static const struct hwmon_ops powr1220_hwmon_ops = {
        .read = powr1220_read,
        .read_string = powr1220_read_string,
        .is_visible = powr1220_is_visible,
};

static const struct hwmon_chip_info powr1220_chip_info = {
        .ops = &powr1220_hwmon_ops,
        .info = powr1220_info,
};

static int powr1220_probe(struct i2c_client *client)
{
        struct powr1220_data *data;
        struct device *hwmon_dev;
        enum powr1xxx_chips chip;

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

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

        chip = (uintptr_t)i2c_get_match_data(client);
        switch (chip) {
        case powr1014:
                data->max_channels = 10;
                break;
        default:
                data->max_channels = 12;
                break;
        }

        data->client = client;

        hwmon_dev = devm_hwmon_device_register_with_info(&client->dev,
                                                         client->name,
                                                         data,
                                                         &powr1220_chip_info,
                                                         NULL);

        return PTR_ERR_OR_ZERO(hwmon_dev);
}

static const struct i2c_device_id powr1220_ids[] = {
        { "powr1014", powr1014, },
        { "powr1220", powr1220, },
        { }
};

MODULE_DEVICE_TABLE(i2c, powr1220_ids);

static struct i2c_driver powr1220_driver = {
        .driver = {
                .name   = "powr1220",
        },
        .probe          = powr1220_probe,
        .id_table       = powr1220_ids,
};

module_i2c_driver(powr1220_driver);

MODULE_AUTHOR("Scott Kanowitz");
MODULE_DESCRIPTION("POWR1220 driver");
MODULE_LICENSE("GPL");