// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Hardware monitoring driver for ZL6100 and compatibles
 *
 * Copyright (c) 2011 Ericsson AB.
 * Copyright (c) 2012 Guenter Roeck
 */

#include <linux/bitops.h>
#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/ktime.h>
#include <linux/delay.h>
#include "pmbus.h"

enum chips { zl2004, zl2005, zl2006, zl2008, zl2105, zl2106, zl6100, zl6105,
             zl8802, zl9101, zl9117, zls1003, zls4009 };

struct zl6100_data {
        int id;
        struct pmbus_driver_info info;
};

#define to_zl6100_data(x)  container_of(x, struct zl6100_data, info)

#define ZL6100_MFR_CONFIG               0xd0
#define ZL6100_DEVICE_ID                0xe4

#define ZL6100_MFR_XTEMP_ENABLE         BIT(7)

#define ZL8802_MFR_USER_GLOBAL_CONFIG   0xe9
#define ZL8802_MFR_TMON_ENABLE          BIT(12)
#define ZL8802_MFR_USER_CONFIG          0xd1
#define ZL8802_MFR_XTEMP_ENABLE_2       BIT(1)
#define ZL8802_MFR_DDC_CONFIG           0xd3
#define ZL8802_MFR_PHASES_MASK          0x0007

#define MFR_VMON_OV_FAULT_LIMIT         0xf5
#define MFR_VMON_UV_FAULT_LIMIT         0xf6
#define MFR_READ_VMON                   0xf7

#define VMON_UV_WARNING                 BIT(5)
#define VMON_OV_WARNING                 BIT(4)
#define VMON_UV_FAULT                   BIT(1)
#define VMON_OV_FAULT                   BIT(0)

#define ZL6100_WAIT_TIME                1000    /* uS   */

static ushort delay = ZL6100_WAIT_TIME;
module_param(delay, ushort, 0644);
MODULE_PARM_DESC(delay, "Delay between chip accesses in uS");

/* Convert linear sensor value to milli-units */
static long zl6100_l2d(s16 l)
{
        s16 exponent;
        s32 mantissa;
        long val;

        exponent = l >> 11;
        mantissa = ((s16)((l & 0x7ff) << 5)) >> 5;

        val = mantissa;

        /* scale result to milli-units */
        val = val * 1000L;

        if (exponent >= 0)
                val <<= exponent;
        else
                val >>= -exponent;

        return val;
}

#define MAX_MANTISSA    (1023 * 1000)
#define MIN_MANTISSA    (511 * 1000)

static u16 zl6100_d2l(long val)
{
        s16 exponent = 0, mantissa;
        bool negative = false;

        /* simple case */
        if (val == 0)
                return 0;

        if (val < 0) {
                negative = true;
                val = -val;
        }

        /* Reduce large mantissa until it fits into 10 bit */
        while (val >= MAX_MANTISSA && exponent < 15) {
                exponent++;
                val >>= 1;
        }
        /* Increase small mantissa to improve precision */
        while (val < MIN_MANTISSA && exponent > -15) {
                exponent--;
                val <<= 1;
        }

        /* Convert mantissa from milli-units to units */
        mantissa = DIV_ROUND_CLOSEST(val, 1000);

        /* Ensure that resulting number is within range */
        if (mantissa > 0x3ff)
                mantissa = 0x3ff;

        /* restore sign */
        if (negative)
                mantissa = -mantissa;

        /* Convert to 5 bit exponent, 11 bit mantissa */
        return (mantissa & 0x7ff) | ((exponent << 11) & 0xf800);
}

static int zl6100_read_word_data(struct i2c_client *client, int page,
                                 int phase, int reg)
{
        const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
        struct zl6100_data *data = to_zl6100_data(info);
        int ret, vreg;

        if (page >= info->pages)
                return -ENXIO;

        if (data->id == zl2005) {
                /*
                 * Limit register detection is not reliable on ZL2005.
                 * Make sure registers are not erroneously detected.
                 */
                switch (reg) {
                case PMBUS_VOUT_OV_WARN_LIMIT:
                case PMBUS_VOUT_UV_WARN_LIMIT:
                case PMBUS_IOUT_OC_WARN_LIMIT:
                        return -ENXIO;
                }
        }

        switch (reg) {
        case PMBUS_VIRT_READ_VMON:
                vreg = MFR_READ_VMON;
                break;
        case PMBUS_VIRT_VMON_OV_WARN_LIMIT:
        case PMBUS_VIRT_VMON_OV_FAULT_LIMIT:
                vreg = MFR_VMON_OV_FAULT_LIMIT;
                break;
        case PMBUS_VIRT_VMON_UV_WARN_LIMIT:
        case PMBUS_VIRT_VMON_UV_FAULT_LIMIT:
                vreg = MFR_VMON_UV_FAULT_LIMIT;
                break;
        default:
                if (reg >= PMBUS_VIRT_BASE)
                        return -ENXIO;
                vreg = reg;
                break;
        }

        ret = pmbus_read_word_data(client, page, phase, vreg);
        if (ret < 0)
                return ret;

        switch (reg) {
        case PMBUS_VIRT_VMON_OV_WARN_LIMIT:
                ret = zl6100_d2l(DIV_ROUND_CLOSEST(zl6100_l2d(ret) * 9, 10));
                break;
        case PMBUS_VIRT_VMON_UV_WARN_LIMIT:
                ret = zl6100_d2l(DIV_ROUND_CLOSEST(zl6100_l2d(ret) * 11, 10));
                break;
        }

        return ret;
}

static int zl6100_read_byte_data(struct i2c_client *client, int page, int reg)
{
        const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
        int ret, status;

        if (page >= info->pages)
                return -ENXIO;

        switch (reg) {
        case PMBUS_VIRT_STATUS_VMON:
                ret = pmbus_read_byte_data(client, 0,
                                           PMBUS_STATUS_MFR_SPECIFIC);
                if (ret < 0)
                        break;

                status = 0;
                if (ret & VMON_UV_WARNING)
                        status |= PB_VOLTAGE_UV_WARNING;
                if (ret & VMON_OV_WARNING)
                        status |= PB_VOLTAGE_OV_WARNING;
                if (ret & VMON_UV_FAULT)
                        status |= PB_VOLTAGE_UV_FAULT;
                if (ret & VMON_OV_FAULT)
                        status |= PB_VOLTAGE_OV_FAULT;
                ret = status;
                break;
        default:
                ret = pmbus_read_byte_data(client, page, reg);
                break;
        }

        return ret;
}

static int zl6100_write_word_data(struct i2c_client *client, int page, int reg,
                                  u16 word)
{
        const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
        int vreg;

        if (page >= info->pages)
                return -ENXIO;

        switch (reg) {
        case PMBUS_VIRT_VMON_OV_WARN_LIMIT:
                word = zl6100_d2l(DIV_ROUND_CLOSEST(zl6100_l2d(word) * 10, 9));
                vreg = MFR_VMON_OV_FAULT_LIMIT;
                pmbus_clear_cache(client);
                break;
        case PMBUS_VIRT_VMON_OV_FAULT_LIMIT:
                vreg = MFR_VMON_OV_FAULT_LIMIT;
                pmbus_clear_cache(client);
                break;
        case PMBUS_VIRT_VMON_UV_WARN_LIMIT:
                word = zl6100_d2l(DIV_ROUND_CLOSEST(zl6100_l2d(word) * 10, 11));
                vreg = MFR_VMON_UV_FAULT_LIMIT;
                pmbus_clear_cache(client);
                break;
        case PMBUS_VIRT_VMON_UV_FAULT_LIMIT:
                vreg = MFR_VMON_UV_FAULT_LIMIT;
                pmbus_clear_cache(client);
                break;
        default:
                if (reg >= PMBUS_VIRT_BASE)
                        return -ENXIO;
                vreg = reg;
        }

        return pmbus_write_word_data(client, page, vreg, word);
}

static const struct i2c_device_id zl6100_id[] = {
        {"bmr450", zl2005},
        {"bmr451", zl2005},
        {"bmr462", zl2008},
        {"bmr463", zl2008},
        {"bmr464", zl2008},
        {"bmr465", zls4009},
        {"bmr466", zls1003},
        {"bmr467", zls4009},
        {"bmr469", zl8802},
        {"zl2004", zl2004},
        {"zl2005", zl2005},
        {"zl2006", zl2006},
        {"zl2008", zl2008},
        {"zl2105", zl2105},
        {"zl2106", zl2106},
        {"zl6100", zl6100},
        {"zl6105", zl6105},
        {"zl8802", zl8802},
        {"zl9101", zl9101},
        {"zl9117", zl9117},
        {"zls1003", zls1003},
        {"zls4009", zls4009},
        { }
};
MODULE_DEVICE_TABLE(i2c, zl6100_id);

static int zl6100_probe(struct i2c_client *client)
{
        int ret, i;
        struct zl6100_data *data;
        struct pmbus_driver_info *info;
        u8 device_id[I2C_SMBUS_BLOCK_MAX + 1];
        const struct i2c_device_id *mid;

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

        ret = i2c_smbus_read_block_data(client, ZL6100_DEVICE_ID,
                                        device_id);
        if (ret < 0) {
                dev_err(&client->dev, "Failed to read device ID\n");
                return ret;
        }
        device_id[ret] = '\0';
        dev_info(&client->dev, "Device ID %s\n", device_id);

        mid = NULL;
        for (mid = zl6100_id; mid->name[0]; mid++) {
                if (!strncasecmp(mid->name, device_id, strlen(mid->name)))
                        break;
        }
        if (!mid->name[0]) {
                dev_err(&client->dev, "Unsupported device\n");
                return -ENODEV;
        }
        if (strcmp(client->name, mid->name) != 0)
                dev_notice(&client->dev,
                           "Device mismatch: Configured %s, detected %s\n",
                           client->name, mid->name);

        data = devm_kzalloc(&client->dev, sizeof(struct zl6100_data),
                            GFP_KERNEL);
        if (!data)
                return -ENOMEM;

        data->id = mid->driver_data;

        /*
         * According to information from the chip vendor, all currently
         * supported chips are known to require a wait time between I2C
         * accesses.
         */
        udelay(delay);

        info = &data->info;

        info->pages = 1;
        info->func[0] = PMBUS_HAVE_VIN | PMBUS_HAVE_STATUS_INPUT
          | PMBUS_HAVE_VOUT | PMBUS_HAVE_STATUS_VOUT
          | PMBUS_HAVE_IOUT | PMBUS_HAVE_STATUS_IOUT
          | PMBUS_HAVE_TEMP | PMBUS_HAVE_STATUS_TEMP;

        /*
         * ZL2004, ZL8802, ZL9101M, ZL9117M and ZLS4009 support monitoring
         * an extra voltage (VMON for ZL2004, ZL8802 and ZLS4009,
         * VDRV for ZL9101M and ZL9117M). Report it as vmon.
         */
        if (data->id == zl2004 || data->id == zl8802 || data->id == zl9101 ||
            data->id == zl9117 || data->id == zls4009)
                info->func[0] |= PMBUS_HAVE_VMON | PMBUS_HAVE_STATUS_VMON;

        /*
         * ZL8802 has two outputs that can be used either independently or in
         * a current sharing configuration. The driver uses the DDC_CONFIG
         * register to check if the module is running with independent or
         * shared outputs. If the module is in shared output mode, only one
         * output voltage will be reported.
         */
        if (data->id == zl8802) {
                info->pages = 2;
                info->func[0] |= PMBUS_HAVE_IIN;

                ret = i2c_smbus_read_word_data(client, ZL8802_MFR_DDC_CONFIG);
                if (ret < 0)
                        return ret;

                udelay(delay);

                if (ret & ZL8802_MFR_PHASES_MASK)
                        info->func[1] |= PMBUS_HAVE_IOUT | PMBUS_HAVE_STATUS_IOUT;
                else
                        info->func[1] = PMBUS_HAVE_VOUT | PMBUS_HAVE_STATUS_VOUT
                                | PMBUS_HAVE_IOUT | PMBUS_HAVE_STATUS_IOUT;

                for (i = 0; i < 2; i++) {
                        ret = i2c_smbus_write_byte_data(client, PMBUS_PAGE, i);
                        if (ret < 0)
                                return ret;

                        udelay(delay);

                        ret = i2c_smbus_read_word_data(client, ZL8802_MFR_USER_CONFIG);
                        if (ret < 0)
                                return ret;

                        if (ret & ZL8802_MFR_XTEMP_ENABLE_2)
                                info->func[i] |= PMBUS_HAVE_TEMP2;

                        udelay(delay);
                }
                ret = i2c_smbus_read_word_data(client, ZL8802_MFR_USER_GLOBAL_CONFIG);
                if (ret < 0)
                        return ret;

                if (ret & ZL8802_MFR_TMON_ENABLE)
                        info->func[0] |= PMBUS_HAVE_TEMP3;
        } else {
                ret = i2c_smbus_read_word_data(client, ZL6100_MFR_CONFIG);
                if (ret < 0)
                        return ret;

                if (ret & ZL6100_MFR_XTEMP_ENABLE)
                        info->func[0] |= PMBUS_HAVE_TEMP2;
        }

        udelay(delay);

        info->access_delay = delay;
        info->read_word_data = zl6100_read_word_data;
        info->read_byte_data = zl6100_read_byte_data;
        info->write_word_data = zl6100_write_word_data;

        return pmbus_do_probe(client, info);
}

static struct i2c_driver zl6100_driver = {
        .driver = {
                   .name = "zl6100",
                   },
        .probe = zl6100_probe,
        .id_table = zl6100_id,
};

module_i2c_driver(zl6100_driver);

MODULE_AUTHOR("Guenter Roeck");
MODULE_DESCRIPTION("PMBus driver for ZL6100 and compatibles");
MODULE_LICENSE("GPL");
MODULE_IMPORT_NS("PMBUS");