// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Hardware monitoring driver for BluTek BPA-RS600 Power Supplies
 *
 * Copyright 2021 Allied Telesis Labs
 */

#include <linux/i2c.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/pmbus.h>
#include "pmbus.h"

enum chips { bpa_rs600, bpd_rs600 };

static int bpa_rs600_read_byte_data(struct i2c_client *client, int page, int reg)
{
        int ret;

        if (page > 0)
                return -ENXIO;

        switch (reg) {
        case PMBUS_FAN_CONFIG_12:
                /*
                 * Two fans are reported in PMBUS_FAN_CONFIG_12 but there is
                 * only one fan in the module. Mask out the FAN2 bits.
                 */
                ret = pmbus_read_byte_data(client, 0, PMBUS_FAN_CONFIG_12);
                if (ret >= 0)
                        ret &= ~(PB_FAN_2_INSTALLED | PB_FAN_2_PULSE_MASK);
                break;
        default:
                ret = -ENODATA;
                break;
        }

        return ret;
}

/*
 * The BPA-RS600 violates the PMBus spec. Specifically it treats the
 * mantissa as unsigned. Deal with this here to allow the PMBus core
 * to work with correctly encoded data.
 */
static int bpa_rs600_read_vin(struct i2c_client *client)
{
        int ret, exponent, mantissa;

        ret = pmbus_read_word_data(client, 0, 0xff, PMBUS_READ_VIN);
        if (ret < 0)
                return ret;

        if (ret & BIT(10)) {
                exponent = ret >> 11;
                mantissa = ret & 0x7ff;

                exponent++;
                mantissa >>= 1;

                ret = (exponent << 11) | mantissa;
        }

        return ret;
}

/*
 * Firmware V5.70 incorrectly reports 1640W for MFR_PIN_MAX.
 * Deal with this by returning a sensible value.
 */
static int bpa_rs600_read_pin_max(struct i2c_client *client)
{
        int ret;

        ret = pmbus_read_word_data(client, 0, 0xff, PMBUS_MFR_PIN_MAX);
        if (ret < 0)
                return ret;

        /* Detect invalid 1640W (linear encoding) */
        if (ret == 0x0b34)
                /* Report 700W (linear encoding) */
                return 0x095e;

        return ret;
}

static int bpa_rs600_read_word_data(struct i2c_client *client, int page, int phase, int reg)
{
        int ret;

        if (page > 0)
                return -ENXIO;

        switch (reg) {
        case PMBUS_VIN_UV_WARN_LIMIT:
        case PMBUS_VIN_OV_WARN_LIMIT:
        case PMBUS_VOUT_UV_WARN_LIMIT:
        case PMBUS_VOUT_OV_WARN_LIMIT:
        case PMBUS_IIN_OC_WARN_LIMIT:
        case PMBUS_IOUT_OC_WARN_LIMIT:
        case PMBUS_PIN_OP_WARN_LIMIT:
        case PMBUS_POUT_OP_WARN_LIMIT:
        case PMBUS_VIN_UV_FAULT_LIMIT:
        case PMBUS_VIN_OV_FAULT_LIMIT:
        case PMBUS_VOUT_UV_FAULT_LIMIT:
        case PMBUS_VOUT_OV_FAULT_LIMIT:
                /* These commands return data but it is invalid/un-documented */
                ret = -ENXIO;
                break;
        case PMBUS_READ_VIN:
                ret = bpa_rs600_read_vin(client);
                break;
        case PMBUS_MFR_PIN_MAX:
                ret = bpa_rs600_read_pin_max(client);
                break;
        default:
                if (reg >= PMBUS_VIRT_BASE)
                        ret = -ENXIO;
                else
                        ret = -ENODATA;
                break;
        }

        return ret;
}

static struct pmbus_driver_info bpa_rs600_info = {
        .pages = 1,
        .format[PSC_VOLTAGE_IN] = linear,
        .format[PSC_VOLTAGE_OUT] = linear,
        .format[PSC_CURRENT_IN] = linear,
        .format[PSC_CURRENT_OUT] = linear,
        .format[PSC_POWER] = linear,
        .format[PSC_TEMPERATURE] = linear,
        .format[PSC_FAN] = linear,
        .func[0] = PMBUS_HAVE_VIN | PMBUS_HAVE_VOUT |
                PMBUS_HAVE_IIN | PMBUS_HAVE_IOUT |
                PMBUS_HAVE_PIN | PMBUS_HAVE_POUT |
                PMBUS_HAVE_TEMP | PMBUS_HAVE_TEMP2 |
                PMBUS_HAVE_FAN12 |
                PMBUS_HAVE_STATUS_VOUT | PMBUS_HAVE_STATUS_IOUT |
                PMBUS_HAVE_STATUS_INPUT | PMBUS_HAVE_STATUS_TEMP |
                PMBUS_HAVE_STATUS_FAN12,
        .read_byte_data = bpa_rs600_read_byte_data,
        .read_word_data = bpa_rs600_read_word_data,
};

static const struct i2c_device_id bpa_rs600_id[] = {
        { "bpa-rs600", bpa_rs600 },
        { "bpd-rs600", bpd_rs600 },
        {},
};
MODULE_DEVICE_TABLE(i2c, bpa_rs600_id);

static int bpa_rs600_probe(struct i2c_client *client)
{
        struct device *dev = &client->dev;
        u8 buf[I2C_SMBUS_BLOCK_MAX + 1];
        int ret;
        const struct i2c_device_id *mid;

        if (!i2c_check_functionality(client->adapter,
                                     I2C_FUNC_SMBUS_READ_BYTE_DATA
                                     | I2C_FUNC_SMBUS_READ_WORD_DATA
                                     | I2C_FUNC_SMBUS_READ_BLOCK_DATA))
                return -ENODEV;

        ret = i2c_smbus_read_block_data(client, PMBUS_MFR_MODEL, buf);
        if (ret < 0) {
                dev_err(dev, "Failed to read Manufacturer Model\n");
                return ret;
        }

        for (mid = bpa_rs600_id; mid->name[0]; mid++) {
                if (!strncasecmp(buf, mid->name, strlen(mid->name)))
                        break;
        }
        if (!mid->name[0]) {
                buf[ret] = '\0';
                dev_err(dev, "Unsupported Manufacturer Model '%s'\n", buf);
                return -ENODEV;
        }

        return pmbus_do_probe(client, &bpa_rs600_info);
}

static const struct of_device_id __maybe_unused bpa_rs600_of_match[] = {
        { .compatible = "blutek,bpa-rs600" },
        {},
};
MODULE_DEVICE_TABLE(of, bpa_rs600_of_match);

static struct i2c_driver bpa_rs600_driver = {
        .driver = {
                .name = "bpa-rs600",
                .of_match_table = of_match_ptr(bpa_rs600_of_match),
        },
        .probe = bpa_rs600_probe,
        .id_table = bpa_rs600_id,
};

module_i2c_driver(bpa_rs600_driver);

MODULE_AUTHOR("Chris Packham");
MODULE_DESCRIPTION("PMBus driver for BluTek BPA-RS600");
MODULE_LICENSE("GPL");
MODULE_IMPORT_NS("PMBUS");