hp6xx_apm.c

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/*
 * bios-less APM driver for hp680
 *
 * Copyright 2005 (c) Andriy Skulysh <[email protected]>
 * Copyright 2008 (c) Kristoffer Ericson <[email protected]>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License.
 */
#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");