// SPDX-License-Identifier: GPL-2.0
/*
 * BQ27xxx battery monitor HDQ/1-wire driver
 *
 * Copyright (C) 2007-2017 Texas Instruments Incorporated - https://www.ti.com/
 *
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/device.h>
#include <linux/types.h>
#include <linux/platform_device.h>
#include <linux/mutex.h>
#include <linux/power/bq27xxx_battery.h>

#include <linux/w1.h>

#define W1_FAMILY_BQ27000       0x01

#define HDQ_CMD_READ    (0 << 7)
#define HDQ_CMD_WRITE   (1 << 7)

static int F_ID;
module_param(F_ID, int, S_IRUSR);
MODULE_PARM_DESC(F_ID, "1-wire slave FID for BQ27xxx device");

static int w1_bq27000_read(struct w1_slave *sl, unsigned int reg)
{
        u8 val;

        mutex_lock(&sl->master->bus_mutex);
        w1_write_8(sl->master, HDQ_CMD_READ | reg);
        val = w1_read_8(sl->master);
        mutex_unlock(&sl->master->bus_mutex);

        return val;
}

static int bq27xxx_battery_hdq_read(struct bq27xxx_device_info *di, u8 reg,
                                    bool single)
{
        struct w1_slave *sl = dev_to_w1_slave(di->dev);
        unsigned int timeout = 3;
        int upper, lower;
        int temp;

        if (!single) {
                /*
                 * Make sure the value has not changed in between reading the
                 * lower and the upper part
                 */
                upper = w1_bq27000_read(sl, reg + 1);
                do {
                        temp = upper;
                        if (upper < 0)
                                return upper;

                        lower = w1_bq27000_read(sl, reg);
                        if (lower < 0)
                                return lower;

                        upper = w1_bq27000_read(sl, reg + 1);
                } while (temp != upper && --timeout);

                if (timeout == 0)
                        return -EIO;

                return (upper << 8) | lower;
        }

        return w1_bq27000_read(sl, reg);
}

static int bq27xxx_battery_hdq_add_slave(struct w1_slave *sl)
{
        struct bq27xxx_device_info *di;

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

        dev_set_drvdata(&sl->dev, di);

        di->dev = &sl->dev;
        di->chip = BQ27000;
        di->name = "bq27000-battery";
        di->bus.read = bq27xxx_battery_hdq_read;

        return bq27xxx_battery_setup(di);
}

static void bq27xxx_battery_hdq_remove_slave(struct w1_slave *sl)
{
        struct bq27xxx_device_info *di = dev_get_drvdata(&sl->dev);

        bq27xxx_battery_teardown(di);
}

static const struct w1_family_ops bq27xxx_battery_hdq_fops = {
        .add_slave      = bq27xxx_battery_hdq_add_slave,
        .remove_slave   = bq27xxx_battery_hdq_remove_slave,
};

static struct w1_family bq27xxx_battery_hdq_family = {
        .fid = W1_FAMILY_BQ27000,
        .fops = &bq27xxx_battery_hdq_fops,
};

static int __init bq27xxx_battery_hdq_init(void)
{
        if (F_ID)
                bq27xxx_battery_hdq_family.fid = F_ID;

        return w1_register_family(&bq27xxx_battery_hdq_family);
}
module_init(bq27xxx_battery_hdq_init);

static void __exit bq27xxx_battery_hdq_exit(void)
{
        w1_unregister_family(&bq27xxx_battery_hdq_family);
}
module_exit(bq27xxx_battery_hdq_exit);

MODULE_AUTHOR("Texas Instruments Ltd");
MODULE_DESCRIPTION("BQ27xxx battery monitor HDQ/1-wire driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS("w1-family-" __stringify(W1_FAMILY_BQ27000));