// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Driver for Lineage Compact Power Line series of power entry modules.
 *
 * Copyright (C) 2010, 2011 Ericsson AB.
 *
 * Documentation:
 *  http://www.lineagepower.com/oem/pdf/CPLI2C.pdf
 */

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

/*
 * This driver supports various Lineage Compact Power Line DC/DC and AC/DC
 * converters such as CP1800, CP2000AC, CP2000DC, CP2100DC, and others.
 *
 * The devices are nominally PMBus compliant. However, most standard PMBus
 * commands are not supported. Specifically, all hardware monitoring and
 * status reporting commands are non-standard. For this reason, a standard
 * PMBus driver can not be used.
 *
 * All Lineage CPL devices have a built-in I2C bus master selector (PCA9541).
 * To ensure device access, this driver should only be used as client driver
 * to the pca9541 I2C master selector driver.
 */

/* Command codes */
#define PEM_OPERATION           0x01
#define PEM_CLEAR_INFO_FLAGS    0x03
#define PEM_VOUT_COMMAND        0x21
#define PEM_VOUT_OV_FAULT_LIMIT 0x40
#define PEM_READ_DATA_STRING    0xd0
#define PEM_READ_INPUT_STRING   0xdc
#define PEM_READ_FIRMWARE_REV   0xdd
#define PEM_READ_RUN_TIMER      0xde
#define PEM_FAN_HI_SPEED        0xdf
#define PEM_FAN_NORMAL_SPEED    0xe0
#define PEM_READ_FAN_SPEED      0xe1

/* offsets in data string */
#define PEM_DATA_STATUS_2       0
#define PEM_DATA_STATUS_1       1
#define PEM_DATA_ALARM_2        2
#define PEM_DATA_ALARM_1        3
#define PEM_DATA_VOUT_LSB       4
#define PEM_DATA_VOUT_MSB       5
#define PEM_DATA_CURRENT        6
#define PEM_DATA_TEMP           7

/* Virtual entries, to report constants */
#define PEM_DATA_TEMP_MAX       10
#define PEM_DATA_TEMP_CRIT      11

/* offsets in input string */
#define PEM_INPUT_VOLTAGE       0
#define PEM_INPUT_POWER_LSB     1
#define PEM_INPUT_POWER_MSB     2

/* offsets in fan data */
#define PEM_FAN_ADJUSTMENT      0
#define PEM_FAN_FAN1            1
#define PEM_FAN_FAN2            2
#define PEM_FAN_FAN3            3

/* Status register bits */
#define STS1_OUTPUT_ON          (1 << 0)
#define STS1_LEDS_FLASHING      (1 << 1)
#define STS1_EXT_FAULT          (1 << 2)
#define STS1_SERVICE_LED_ON     (1 << 3)
#define STS1_SHUTDOWN_OCCURRED  (1 << 4)
#define STS1_INT_FAULT          (1 << 5)
#define STS1_ISOLATION_TEST_OK  (1 << 6)

#define STS2_ENABLE_PIN_HI      (1 << 0)
#define STS2_DATA_OUT_RANGE     (1 << 1)
#define STS2_RESTARTED_OK       (1 << 1)
#define STS2_ISOLATION_TEST_FAIL (1 << 3)
#define STS2_HIGH_POWER_CAP     (1 << 4)
#define STS2_INVALID_INSTR      (1 << 5)
#define STS2_WILL_RESTART       (1 << 6)
#define STS2_PEC_ERR            (1 << 7)

/* Alarm register bits */
#define ALRM1_VIN_OUT_LIMIT     (1 << 0)
#define ALRM1_VOUT_OUT_LIMIT    (1 << 1)
#define ALRM1_OV_VOLT_SHUTDOWN  (1 << 2)
#define ALRM1_VIN_OVERCURRENT   (1 << 3)
#define ALRM1_TEMP_WARNING      (1 << 4)
#define ALRM1_TEMP_SHUTDOWN     (1 << 5)
#define ALRM1_PRIMARY_FAULT     (1 << 6)
#define ALRM1_POWER_LIMIT       (1 << 7)

#define ALRM2_5V_OUT_LIMIT      (1 << 1)
#define ALRM2_TEMP_FAULT        (1 << 2)
#define ALRM2_OV_LOW            (1 << 3)
#define ALRM2_DCDC_TEMP_HIGH    (1 << 4)
#define ALRM2_PRI_TEMP_HIGH     (1 << 5)
#define ALRM2_NO_PRIMARY        (1 << 6)
#define ALRM2_FAN_FAULT         (1 << 7)

#define FIRMWARE_REV_LEN        4
#define DATA_STRING_LEN         9
#define INPUT_STRING_LEN        5       /* 4 for most devices   */
#define FAN_SPEED_LEN           5

struct pem_data {
        struct i2c_client *client;
        const struct attribute_group *groups[4];

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

        u8 firmware_rev[FIRMWARE_REV_LEN];
        u8 data_string[DATA_STRING_LEN];
        u8 input_string[INPUT_STRING_LEN];
        u8 fan_speed[FAN_SPEED_LEN];
};

static int pem_read_block(struct i2c_client *client, u8 command, u8 *data,
                          int data_len)
{
        u8 block_buffer[I2C_SMBUS_BLOCK_MAX];
        int result;

        result = i2c_smbus_read_block_data(client, command, block_buffer);
        if (unlikely(result < 0))
                goto abort;
        if (unlikely(result == 0xff || result != data_len)) {
                result = -EIO;
                goto abort;
        }
        memcpy(data, block_buffer, data_len);
        result = 0;
abort:
        return result;
}

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

        mutex_lock(&data->update_lock);

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

                /* Read data string */
                result = pem_read_block(client, PEM_READ_DATA_STRING,
                                        data->data_string,
                                        sizeof(data->data_string));
                if (unlikely(result < 0)) {
                        ret = ERR_PTR(result);
                        goto abort;
                }

                /* Read input string */
                if (data->input_length) {
                        result = pem_read_block(client, PEM_READ_INPUT_STRING,
                                                data->input_string,
                                                data->input_length);
                        if (unlikely(result < 0)) {
                                ret = ERR_PTR(result);
                                goto abort;
                        }
                }

                /* Read fan speeds */
                if (data->fans_supported) {
                        result = pem_read_block(client, PEM_READ_FAN_SPEED,
                                                data->fan_speed,
                                                sizeof(data->fan_speed));
                        if (unlikely(result < 0)) {
                                ret = ERR_PTR(result);
                                goto abort;
                        }
                }

                i2c_smbus_write_byte(client, PEM_CLEAR_INFO_FLAGS);

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

static long pem_get_data(u8 *data, int len, int index)
{
        long val;

        switch (index) {
        case PEM_DATA_VOUT_LSB:
                val = (data[index] + (data[index+1] << 8)) * 5 / 2;
                break;
        case PEM_DATA_CURRENT:
                val = data[index] * 200;
                break;
        case PEM_DATA_TEMP:
                val = data[index] * 1000;
                break;
        case PEM_DATA_TEMP_MAX:
                val = 97 * 1000;        /* 97 degrees C per datasheet */
                break;
        case PEM_DATA_TEMP_CRIT:
                val = 107 * 1000;       /* 107 degrees C per datasheet */
                break;
        default:
                WARN_ON_ONCE(1);
                val = 0;
        }
        return val;
}

static long pem_get_input(u8 *data, int len, int index)
{
        long val;

        switch (index) {
        case PEM_INPUT_VOLTAGE:
                if (len == INPUT_STRING_LEN)
                        val = (data[index] + (data[index+1] << 8) - 75) * 1000;
                else
                        val = (data[index] - 75) * 1000;
                break;
        case PEM_INPUT_POWER_LSB:
                if (len == INPUT_STRING_LEN)
                        index++;
                val = (data[index] + (data[index+1] << 8)) * 1000000L;
                break;
        default:
                WARN_ON_ONCE(1);
                val = 0;
        }
        return val;
}

static long pem_get_fan(u8 *data, int len, int index)
{
        long val;

        switch (index) {
        case PEM_FAN_FAN1:
        case PEM_FAN_FAN2:
        case PEM_FAN_FAN3:
                val = data[index] * 100;
                break;
        default:
                WARN_ON_ONCE(1);
                val = 0;
        }
        return val;
}

/*
 * Show boolean, either a fault or an alarm.
 * .nr points to the register, .index is the bit mask to check
 */
static ssize_t pem_bool_show(struct device *dev, struct device_attribute *da,
                             char *buf)
{
        struct sensor_device_attribute_2 *attr = to_sensor_dev_attr_2(da);
        struct pem_data *data = pem_update_device(dev);
        u8 status;

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

        status = data->data_string[attr->nr] & attr->index;
        return sysfs_emit(buf, "%d\n", !!status);
}

static ssize_t pem_data_show(struct device *dev, struct device_attribute *da,
                             char *buf)
{
        struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
        struct pem_data *data = pem_update_device(dev);
        long value;

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

        value = pem_get_data(data->data_string, sizeof(data->data_string),
                             attr->index);

        return sysfs_emit(buf, "%ld\n", value);
}

static ssize_t pem_input_show(struct device *dev, struct device_attribute *da,
                              char *buf)
{
        struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
        struct pem_data *data = pem_update_device(dev);
        long value;

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

        value = pem_get_input(data->input_string, sizeof(data->input_string),
                              attr->index);

        return sysfs_emit(buf, "%ld\n", value);
}

static ssize_t pem_fan_show(struct device *dev, struct device_attribute *da,
                            char *buf)
{
        struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
        struct pem_data *data = pem_update_device(dev);
        long value;

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

        value = pem_get_fan(data->fan_speed, sizeof(data->fan_speed),
                            attr->index);

        return sysfs_emit(buf, "%ld\n", value);
}

/* Voltages */
static SENSOR_DEVICE_ATTR_RO(in1_input, pem_data, PEM_DATA_VOUT_LSB);
static SENSOR_DEVICE_ATTR_2_RO(in1_alarm, pem_bool, PEM_DATA_ALARM_1,
                               ALRM1_VOUT_OUT_LIMIT);
static SENSOR_DEVICE_ATTR_2_RO(in1_crit_alarm, pem_bool, PEM_DATA_ALARM_1,
                               ALRM1_OV_VOLT_SHUTDOWN);
static SENSOR_DEVICE_ATTR_RO(in2_input, pem_input, PEM_INPUT_VOLTAGE);
static SENSOR_DEVICE_ATTR_2_RO(in2_alarm, pem_bool, PEM_DATA_ALARM_1,
                               ALRM1_VIN_OUT_LIMIT | ALRM1_PRIMARY_FAULT);

/* Currents */
static SENSOR_DEVICE_ATTR_RO(curr1_input, pem_data, PEM_DATA_CURRENT);
static SENSOR_DEVICE_ATTR_2_RO(curr1_alarm, pem_bool, PEM_DATA_ALARM_1,
                               ALRM1_VIN_OVERCURRENT);

/* Power */
static SENSOR_DEVICE_ATTR_RO(power1_input, pem_input, PEM_INPUT_POWER_LSB);
static SENSOR_DEVICE_ATTR_2_RO(power1_alarm, pem_bool, PEM_DATA_ALARM_1,
                               ALRM1_POWER_LIMIT);

/* Fans */
static SENSOR_DEVICE_ATTR_RO(fan1_input, pem_fan, PEM_FAN_FAN1);
static SENSOR_DEVICE_ATTR_RO(fan2_input, pem_fan, PEM_FAN_FAN2);
static SENSOR_DEVICE_ATTR_RO(fan3_input, pem_fan, PEM_FAN_FAN3);
static SENSOR_DEVICE_ATTR_2_RO(fan1_alarm, pem_bool, PEM_DATA_ALARM_2,
                               ALRM2_FAN_FAULT);

/* Temperatures */
static SENSOR_DEVICE_ATTR_RO(temp1_input, pem_data, PEM_DATA_TEMP);
static SENSOR_DEVICE_ATTR_RO(temp1_max, pem_data, PEM_DATA_TEMP_MAX);
static SENSOR_DEVICE_ATTR_RO(temp1_crit, pem_data, PEM_DATA_TEMP_CRIT);
static SENSOR_DEVICE_ATTR_2_RO(temp1_alarm, pem_bool, PEM_DATA_ALARM_1,
                               ALRM1_TEMP_WARNING);
static SENSOR_DEVICE_ATTR_2_RO(temp1_crit_alarm, pem_bool, PEM_DATA_ALARM_1,
                               ALRM1_TEMP_SHUTDOWN);
static SENSOR_DEVICE_ATTR_2_RO(temp1_fault, pem_bool, PEM_DATA_ALARM_2,
                               ALRM2_TEMP_FAULT);

static struct attribute *pem_attributes[] = {
        &sensor_dev_attr_in1_input.dev_attr.attr,
        &sensor_dev_attr_in1_alarm.dev_attr.attr,
        &sensor_dev_attr_in1_crit_alarm.dev_attr.attr,
        &sensor_dev_attr_in2_alarm.dev_attr.attr,

        &sensor_dev_attr_curr1_alarm.dev_attr.attr,

        &sensor_dev_attr_power1_alarm.dev_attr.attr,

        &sensor_dev_attr_fan1_alarm.dev_attr.attr,

        &sensor_dev_attr_temp1_input.dev_attr.attr,
        &sensor_dev_attr_temp1_max.dev_attr.attr,
        &sensor_dev_attr_temp1_crit.dev_attr.attr,
        &sensor_dev_attr_temp1_alarm.dev_attr.attr,
        &sensor_dev_attr_temp1_crit_alarm.dev_attr.attr,
        &sensor_dev_attr_temp1_fault.dev_attr.attr,

        NULL,
};

static const struct attribute_group pem_group = {
        .attrs = pem_attributes,
};

static struct attribute *pem_input_attributes[] = {
        &sensor_dev_attr_in2_input.dev_attr.attr,
        &sensor_dev_attr_curr1_input.dev_attr.attr,
        &sensor_dev_attr_power1_input.dev_attr.attr,
        NULL
};

static const struct attribute_group pem_input_group = {
        .attrs = pem_input_attributes,
};

static struct attribute *pem_fan_attributes[] = {
        &sensor_dev_attr_fan1_input.dev_attr.attr,
        &sensor_dev_attr_fan2_input.dev_attr.attr,
        &sensor_dev_attr_fan3_input.dev_attr.attr,
        NULL
};

static const struct attribute_group pem_fan_group = {
        .attrs = pem_fan_attributes,
};

static int pem_probe(struct i2c_client *client)
{
        struct i2c_adapter *adapter = client->adapter;
        struct device *dev = &client->dev;
        struct device *hwmon_dev;
        struct pem_data *data;
        int ret, idx = 0;

        if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BLOCK_DATA
                                     | I2C_FUNC_SMBUS_WRITE_BYTE))
                return -ENODEV;

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

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

        /*
         * We use the next two commands to determine if the device is really
         * there.
         */
        ret = pem_read_block(client, PEM_READ_FIRMWARE_REV,
                             data->firmware_rev, sizeof(data->firmware_rev));
        if (ret < 0)
                return ret;

        ret = i2c_smbus_write_byte(client, PEM_CLEAR_INFO_FLAGS);
        if (ret < 0)
                return ret;

        dev_info(dev, "Firmware revision %d.%d.%d\n",
                 data->firmware_rev[0], data->firmware_rev[1],
                 data->firmware_rev[2]);

        /* sysfs hooks */
        data->groups[idx++] = &pem_group;

        /*
         * Check if input readings are supported.
         * This is the case if we can read input data,
         * and if the returned data is not all zeros.
         * Note that input alarms are always supported.
         */
        ret = pem_read_block(client, PEM_READ_INPUT_STRING,
                             data->input_string,
                             sizeof(data->input_string) - 1);
        if (!ret && (data->input_string[0] || data->input_string[1] ||
                     data->input_string[2]))
                data->input_length = sizeof(data->input_string) - 1;
        else if (ret < 0) {
                /* Input string is one byte longer for some devices */
                ret = pem_read_block(client, PEM_READ_INPUT_STRING,
                                    data->input_string,
                                    sizeof(data->input_string));
                if (!ret && (data->input_string[0] || data->input_string[1] ||
                            data->input_string[2] || data->input_string[3]))
                        data->input_length = sizeof(data->input_string);
        }

        if (data->input_length)
                data->groups[idx++] = &pem_input_group;

        /*
         * Check if fan speed readings are supported.
         * This is the case if we can read fan speed data,
         * and if the returned data is not all zeros.
         * Note that the fan alarm is always supported.
         */
        ret = pem_read_block(client, PEM_READ_FAN_SPEED,
                             data->fan_speed,
                             sizeof(data->fan_speed));
        if (!ret && (data->fan_speed[0] || data->fan_speed[1] ||
                     data->fan_speed[2] || data->fan_speed[3])) {
                data->fans_supported = true;
                data->groups[idx++] = &pem_fan_group;
        }

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

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

static struct i2c_driver pem_driver = {
        .driver = {
                   .name = "lineage_pem",
                   },
        .probe = pem_probe,
        .id_table = pem_id,
};

module_i2c_driver(pem_driver);

MODULE_AUTHOR("Guenter Roeck <linux@roeck-us.net>");
MODULE_DESCRIPTION("Lineage CPL PEM hardware monitoring driver");
MODULE_LICENSE("GPL");