// SPDX-License-Identifier: GPL-2.0
/*
 * bios-less APM driver for hp680
 *
 * Copyright 2005 (c) Andriy Skulysh <askulysh@gmail.com>
 * Copyright 2008 (c) Kristoffer Ericson <kristoffer.ericson@gmail.com>
 */
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/apm-emulation.h>
#include <linux/io.h>
#include <asm/adc.h>
#include <mach/hp6xx.h>

/* percentage values */
#define APM_CRITICAL                    10
#define APM_LOW                         30

/* resonably sane values */
#define HP680_BATTERY_MAX               898
#define HP680_BATTERY_MIN               486
#define HP680_BATTERY_AC_ON             1023

#define MODNAME "hp6x0_apm"

#define PGDR    0xa400012c

static void hp6x0_apm_get_power_status(struct apm_power_info *info)
{
        int battery, backup, charging, percentage;
        u8 pgdr;

        battery         = adc_single(ADC_CHANNEL_BATTERY);
        backup          = adc_single(ADC_CHANNEL_BACKUP);
        charging        = adc_single(ADC_CHANNEL_CHARGE);

        percentage = 100 * (battery - HP680_BATTERY_MIN) /
                           (HP680_BATTERY_MAX - HP680_BATTERY_MIN);

        /* % of full battery */
        info->battery_life = percentage;

        /* We want our estimates in minutes */
        info->units = 0;

        /* Extremely(!!) rough estimate, we will replace this with a datalist later on */
        info->time = (2 * battery);

        info->ac_line_status = (battery > HP680_BATTERY_AC_ON) ?
                         APM_AC_ONLINE : APM_AC_OFFLINE;

        pgdr = __raw_readb(PGDR);
        if (pgdr & PGDR_MAIN_BATTERY_OUT) {
                info->battery_status    = APM_BATTERY_STATUS_NOT_PRESENT;
                info->battery_flag      = 0x80;
        } else if (charging < 8) {
                info->battery_status    = APM_BATTERY_STATUS_CHARGING;
                info->battery_flag      = 0x08;
                info->ac_line_status    = 0x01;
        } else if (percentage <= APM_CRITICAL) {
                info->battery_status    = APM_BATTERY_STATUS_CRITICAL;
                info->battery_flag      = 0x04;
        } else if (percentage <= APM_LOW) {
                info->battery_status    = APM_BATTERY_STATUS_LOW;
                info->battery_flag      = 0x02;
        } else {
                info->battery_status    = APM_BATTERY_STATUS_HIGH;
                info->battery_flag      = 0x01;
        }
}

static irqreturn_t hp6x0_apm_interrupt(int irq, void *dev)
{
        if (!APM_DISABLED)
                apm_queue_event(APM_USER_SUSPEND);

        return IRQ_HANDLED;
}

static int __init hp6x0_apm_init(void)
{
        int ret;

        ret = request_irq(HP680_BTN_IRQ, hp6x0_apm_interrupt,
                          0, MODNAME, NULL);
        if (unlikely(ret < 0)) {
                printk(KERN_ERR MODNAME ": IRQ %d request failed\n",
                       HP680_BTN_IRQ);
                return ret;
        }

        apm_get_power_status = hp6x0_apm_get_power_status;

        return ret;
}

static void __exit hp6x0_apm_exit(void)
{
        free_irq(HP680_BTN_IRQ, 0);
}

module_init(hp6x0_apm_init);
module_exit(hp6x0_apm_exit);

MODULE_AUTHOR("Adriy Skulysh");
MODULE_DESCRIPTION("hp6xx Advanced Power Management");
MODULE_LICENSE("GPL");