// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * APM emulation for PMU-based machines
 *
 * Copyright 2001 Benjamin Herrenschmidt (benh@kernel.crashing.org)
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/apm-emulation.h>
#include <linux/adb.h>
#include <linux/pmu.h>

#define APM_CRITICAL            10
#define APM_LOW                 30

static void pmu_apm_get_power_status(struct apm_power_info *info)
{
        int percentage = -1;
        int batteries = 0;
        int time_units = -1;
        int real_count = 0;
        int i;
        char charging = 0;
        long charge = -1;
        long amperage = 0;
        unsigned long btype = 0;

        info->battery_status = APM_BATTERY_STATUS_UNKNOWN;
        info->battery_flag = APM_BATTERY_FLAG_UNKNOWN;
        info->units = APM_UNITS_MINS;

        if (pmu_power_flags & PMU_PWR_AC_PRESENT)
                info->ac_line_status = APM_AC_ONLINE;
        else
                info->ac_line_status = APM_AC_OFFLINE;

        for (i=0; i<pmu_battery_count; i++) {
                if (pmu_batteries[i].flags & PMU_BATT_PRESENT) {
                        batteries++;
                        if (percentage < 0)
                                percentage = 0;
                        if (charge < 0)
                                charge = 0;
                        percentage += (pmu_batteries[i].charge * 100) /
                                pmu_batteries[i].max_charge;
                        charge += pmu_batteries[i].charge;
                        amperage += pmu_batteries[i].amperage;
                        if (btype == 0)
                                btype = (pmu_batteries[i].flags & PMU_BATT_TYPE_MASK);
                        real_count++;
                        if ((pmu_batteries[i].flags & PMU_BATT_CHARGING))
                                charging++;
                }
        }
        if (batteries == 0)
                info->ac_line_status = APM_AC_ONLINE;

        if (real_count) {
                if (amperage < 0) {
                        if (btype == PMU_BATT_TYPE_SMART)
                                time_units = (charge * 59) / (amperage * -1);
                        else
                                time_units = (charge * 16440) / (amperage * -60);
                }
                percentage /= real_count;
                if (charging > 0) {
                        info->battery_status = APM_BATTERY_STATUS_CHARGING;
                        info->battery_flag = APM_BATTERY_FLAG_CHARGING;
                } else if (percentage <= APM_CRITICAL) {
                        info->battery_status = APM_BATTERY_STATUS_CRITICAL;
                        info->battery_flag = APM_BATTERY_FLAG_CRITICAL;
                } else if (percentage <= APM_LOW) {
                        info->battery_status = APM_BATTERY_STATUS_LOW;
                        info->battery_flag = APM_BATTERY_FLAG_LOW;
                } else {
                        info->battery_status = APM_BATTERY_STATUS_HIGH;
                        info->battery_flag = APM_BATTERY_FLAG_HIGH;
                }
        }

        info->battery_life = percentage;
        info->time = time_units;
}

static int __init apm_emu_init(void)
{
        apm_get_power_status = pmu_apm_get_power_status;

        printk(KERN_INFO "apm_emu: PMU APM Emulation initialized.\n");

        return 0;
}

static void __exit apm_emu_exit(void)
{
        if (apm_get_power_status == pmu_apm_get_power_status)
                apm_get_power_status = NULL;

        printk(KERN_INFO "apm_emu: PMU APM Emulation removed.\n");
}

module_init(apm_emu_init);
module_exit(apm_emu_exit);

MODULE_AUTHOR("Benjamin Herrenschmidt");
MODULE_DESCRIPTION("APM emulation for PowerMac");
MODULE_LICENSE("GPL");