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linux-stable/drivers/power/s3c_adc_battery.c
Heiko Stübner 34aed73df3 s3c_adc_battery: Average over more than one adc sample 
Some sources for adc battery information provide only inaccurate results
where the read value differs from the real value with positive and negative
offsets. For such sources it can be more accurate to collect two or more
value sample and use the average of all collected values.

This patch adds pdata options volt_samples, current_samples and
backup_volt_samples to specifiy the number of samples to collect,
reads the specified number of samples and calculates the average of those.
For unset sample-number-values a default of 1 is assumed.

Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Signed-off-by: Anton Vorontsov <cbouatmailru@gmail.com>
2012-01-06 06:13:35 +04:00

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/*
* iPAQ h1930/h1940/rx1950 battery controller driver
* Copyright (c) Vasily Khoruzhick
* Based on h1940_battery.c by Arnaud Patard
*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file COPYING in the main directory of this archive for
* more details.
*
*/
#include <linux/interrupt.h>
#include <linux/platform_device.h>
#include <linux/power_supply.h>
#include <linux/leds.h>
#include <linux/gpio.h>
#include <linux/err.h>
#include <linux/timer.h>
#include <linux/jiffies.h>
#include <linux/s3c_adc_battery.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/module.h>
#include <plat/adc.h>
#define BAT_POLL_INTERVAL 10000 /* ms */
#define JITTER_DELAY 500 /* ms */
struct s3c_adc_bat {
struct power_supply psy;
struct s3c_adc_client *client;
struct s3c_adc_bat_pdata *pdata;
int volt_value;
int cur_value;
unsigned int timestamp;
int level;
int status;
int cable_plugged:1;
};
static struct delayed_work bat_work;
static void s3c_adc_bat_ext_power_changed(struct power_supply *psy)
{
schedule_delayed_work(&bat_work,
msecs_to_jiffies(JITTER_DELAY));
}
static int gather_samples(struct s3c_adc_client *client, int num, int channel)
{
int value, i;
/* default to 1 if nothing is set */
if (num < 1)
num = 1;
value = 0;
for (i = 0; i < num; i++)
value += s3c_adc_read(client, channel);
value /= num;
return value;
}
static enum power_supply_property s3c_adc_backup_bat_props[] = {
POWER_SUPPLY_PROP_VOLTAGE_NOW,
POWER_SUPPLY_PROP_VOLTAGE_MIN,
POWER_SUPPLY_PROP_VOLTAGE_MAX_DESIGN,
};
static int s3c_adc_backup_bat_get_property(struct power_supply *psy,
enum power_supply_property psp,
union power_supply_propval *val)
{
struct s3c_adc_bat *bat = container_of(psy, struct s3c_adc_bat, psy);
if (!bat) {
dev_err(psy->dev, "%s: no battery infos ?!\n", __func__);
return -EINVAL;
}
if (bat->volt_value < 0 ||
jiffies_to_msecs(jiffies - bat->timestamp) >
BAT_POLL_INTERVAL) {
bat->volt_value = gather_samples(bat->client,
bat->pdata->backup_volt_samples,
bat->pdata->backup_volt_channel);
bat->volt_value *= bat->pdata->backup_volt_mult;
bat->timestamp = jiffies;
}
switch (psp) {
case POWER_SUPPLY_PROP_VOLTAGE_NOW:
val->intval = bat->volt_value;
return 0;
case POWER_SUPPLY_PROP_VOLTAGE_MIN:
val->intval = bat->pdata->backup_volt_min;
return 0;
case POWER_SUPPLY_PROP_VOLTAGE_MAX_DESIGN:
val->intval = bat->pdata->backup_volt_max;
return 0;
default:
return -EINVAL;
}
}
static struct s3c_adc_bat backup_bat = {
.psy = {
.name = "backup-battery",
.type = POWER_SUPPLY_TYPE_BATTERY,
.properties = s3c_adc_backup_bat_props,
.num_properties = ARRAY_SIZE(s3c_adc_backup_bat_props),
.get_property = s3c_adc_backup_bat_get_property,
.use_for_apm = 1,
},
};
static enum power_supply_property s3c_adc_main_bat_props[] = {
POWER_SUPPLY_PROP_STATUS,
POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN,
POWER_SUPPLY_PROP_CHARGE_EMPTY_DESIGN,
POWER_SUPPLY_PROP_CHARGE_NOW,
POWER_SUPPLY_PROP_VOLTAGE_NOW,
POWER_SUPPLY_PROP_CURRENT_NOW,
};
static int calc_full_volt(int volt_val, int cur_val, int impedance)
{
return volt_val + cur_val * impedance / 1000;
}
static int charge_finished(struct s3c_adc_bat *bat)
{
return bat->pdata->gpio_inverted ?
!gpio_get_value(bat->pdata->gpio_charge_finished) :
gpio_get_value(bat->pdata->gpio_charge_finished);
}
static int s3c_adc_bat_get_property(struct power_supply *psy,
enum power_supply_property psp,
union power_supply_propval *val)
{
struct s3c_adc_bat *bat = container_of(psy, struct s3c_adc_bat, psy);
int new_level;
int full_volt;
const struct s3c_adc_bat_thresh *lut = bat->pdata->lut_noac;
unsigned int lut_size = bat->pdata->lut_noac_cnt;
if (!bat) {
dev_err(psy->dev, "no battery infos ?!\n");
return -EINVAL;
}
if (bat->volt_value < 0 || bat->cur_value < 0 ||
jiffies_to_msecs(jiffies - bat->timestamp) >
BAT_POLL_INTERVAL) {
bat->volt_value = gather_samples(bat->client,
bat->pdata->volt_samples,
bat->pdata->volt_channel) * bat->pdata->volt_mult;
bat->cur_value = gather_samples(bat->client,
bat->pdata->current_samples,
bat->pdata->current_channel) * bat->pdata->current_mult;
bat->timestamp = jiffies;
}
if (bat->cable_plugged &&
((bat->pdata->gpio_charge_finished < 0) ||
!charge_finished(bat))) {
lut = bat->pdata->lut_acin;
lut_size = bat->pdata->lut_acin_cnt;
}
new_level = 100000;
full_volt = calc_full_volt((bat->volt_value / 1000),
(bat->cur_value / 1000), bat->pdata->internal_impedance);
if (full_volt < calc_full_volt(lut->volt, lut->cur,
bat->pdata->internal_impedance)) {
lut_size--;
while (lut_size--) {
int lut_volt1;
int lut_volt2;
lut_volt1 = calc_full_volt(lut[0].volt, lut[0].cur,
bat->pdata->internal_impedance);
lut_volt2 = calc_full_volt(lut[1].volt, lut[1].cur,
bat->pdata->internal_impedance);
if (full_volt < lut_volt1 && full_volt >= lut_volt2) {
new_level = (lut[1].level +
(lut[0].level - lut[1].level) *
(full_volt - lut_volt2) /
(lut_volt1 - lut_volt2)) * 1000;
break;
}
new_level = lut[1].level * 1000;
lut++;
}
}
bat->level = new_level;
switch (psp) {
case POWER_SUPPLY_PROP_STATUS:
if (bat->pdata->gpio_charge_finished < 0)
val->intval = bat->level == 100000 ?
POWER_SUPPLY_STATUS_FULL : bat->status;
else
val->intval = bat->status;
return 0;
case POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN:
val->intval = 100000;
return 0;
case POWER_SUPPLY_PROP_CHARGE_EMPTY_DESIGN:
val->intval = 0;
return 0;
case POWER_SUPPLY_PROP_CHARGE_NOW:
val->intval = bat->level;
return 0;
case POWER_SUPPLY_PROP_VOLTAGE_NOW:
val->intval = bat->volt_value;
return 0;
case POWER_SUPPLY_PROP_CURRENT_NOW:
val->intval = bat->cur_value;
return 0;
default:
return -EINVAL;
}
}
static struct s3c_adc_bat main_bat = {
.psy = {
.name = "main-battery",
.type = POWER_SUPPLY_TYPE_BATTERY,
.properties = s3c_adc_main_bat_props,
.num_properties = ARRAY_SIZE(s3c_adc_main_bat_props),
.get_property = s3c_adc_bat_get_property,
.external_power_changed = s3c_adc_bat_ext_power_changed,
.use_for_apm = 1,
},
};
static void s3c_adc_bat_work(struct work_struct *work)
{
struct s3c_adc_bat *bat = &main_bat;
int is_charged;
int is_plugged;
static int was_plugged;
is_plugged = power_supply_am_i_supplied(&bat->psy);
bat->cable_plugged = is_plugged;
if (is_plugged != was_plugged) {
was_plugged = is_plugged;
if (is_plugged) {
if (bat->pdata->enable_charger)
bat->pdata->enable_charger();
bat->status = POWER_SUPPLY_STATUS_CHARGING;
} else {
if (bat->pdata->disable_charger)
bat->pdata->disable_charger();
bat->status = POWER_SUPPLY_STATUS_DISCHARGING;
}
} else {
if ((bat->pdata->gpio_charge_finished >= 0) && is_plugged) {
is_charged = charge_finished(&main_bat);
if (is_charged) {
if (bat->pdata->disable_charger)
bat->pdata->disable_charger();
bat->status = POWER_SUPPLY_STATUS_FULL;
} else {
if (bat->pdata->enable_charger)
bat->pdata->enable_charger();
bat->status = POWER_SUPPLY_STATUS_CHARGING;
}
}
}
power_supply_changed(&bat->psy);
}
static irqreturn_t s3c_adc_bat_charged(int irq, void *dev_id)
{
schedule_delayed_work(&bat_work,
msecs_to_jiffies(JITTER_DELAY));
return IRQ_HANDLED;
}
static int __devinit s3c_adc_bat_probe(struct platform_device *pdev)
{
struct s3c_adc_client *client;
struct s3c_adc_bat_pdata *pdata = pdev->dev.platform_data;
int ret;
client = s3c_adc_register(pdev, NULL, NULL, 0);
if (IS_ERR(client)) {
dev_err(&pdev->dev, "cannot register adc\n");
return PTR_ERR(client);
}
platform_set_drvdata(pdev, client);
main_bat.client = client;
main_bat.pdata = pdata;
main_bat.volt_value = -1;
main_bat.cur_value = -1;
main_bat.cable_plugged = 0;
main_bat.status = POWER_SUPPLY_STATUS_DISCHARGING;
ret = power_supply_register(&pdev->dev, &main_bat.psy);
if (ret)
goto err_reg_main;
if (pdata->backup_volt_mult) {
backup_bat.client = client;
backup_bat.pdata = pdev->dev.platform_data;
backup_bat.volt_value = -1;
ret = power_supply_register(&pdev->dev, &backup_bat.psy);
if (ret)
goto err_reg_backup;
}
INIT_DELAYED_WORK(&bat_work, s3c_adc_bat_work);
if (pdata->gpio_charge_finished >= 0) {
ret = gpio_request(pdata->gpio_charge_finished, "charged");
if (ret)
goto err_gpio;
ret = request_irq(gpio_to_irq(pdata->gpio_charge_finished),
s3c_adc_bat_charged,
IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING,
"battery charged", NULL);
if (ret)
goto err_irq;
}
if (pdata->init) {
ret = pdata->init();
if (ret)
goto err_platform;
}
dev_info(&pdev->dev, "successfully loaded\n");
device_init_wakeup(&pdev->dev, 1);
/* Schedule timer to check current status */
schedule_delayed_work(&bat_work,
msecs_to_jiffies(JITTER_DELAY));
return 0;
err_platform:
if (pdata->gpio_charge_finished >= 0)
free_irq(gpio_to_irq(pdata->gpio_charge_finished), NULL);
err_irq:
if (pdata->gpio_charge_finished >= 0)
gpio_free(pdata->gpio_charge_finished);
err_gpio:
if (pdata->backup_volt_mult)
power_supply_unregister(&backup_bat.psy);
err_reg_backup:
power_supply_unregister(&main_bat.psy);
err_reg_main:
return ret;
}
static int s3c_adc_bat_remove(struct platform_device *pdev)
{
struct s3c_adc_client *client = platform_get_drvdata(pdev);
struct s3c_adc_bat_pdata *pdata = pdev->dev.platform_data;
power_supply_unregister(&main_bat.psy);
if (pdata->backup_volt_mult)
power_supply_unregister(&backup_bat.psy);
s3c_adc_release(client);
if (pdata->gpio_charge_finished >= 0) {
free_irq(gpio_to_irq(pdata->gpio_charge_finished), NULL);
gpio_free(pdata->gpio_charge_finished);
}
cancel_delayed_work(&bat_work);
if (pdata->exit)
pdata->exit();
return 0;
}
#ifdef CONFIG_PM
static int s3c_adc_bat_suspend(struct platform_device *pdev,
pm_message_t state)
{
struct s3c_adc_bat_pdata *pdata = pdev->dev.platform_data;
if (pdata->gpio_charge_finished >= 0) {
if (device_may_wakeup(&pdev->dev))
enable_irq_wake(
gpio_to_irq(pdata->gpio_charge_finished));
else {
disable_irq(gpio_to_irq(pdata->gpio_charge_finished));
main_bat.pdata->disable_charger();
}
}
return 0;
}
static int s3c_adc_bat_resume(struct platform_device *pdev)
{
struct s3c_adc_bat_pdata *pdata = pdev->dev.platform_data;
if (pdata->gpio_charge_finished >= 0) {
if (device_may_wakeup(&pdev->dev))
disable_irq_wake(
gpio_to_irq(pdata->gpio_charge_finished));
else
enable_irq(gpio_to_irq(pdata->gpio_charge_finished));
}
/* Schedule timer to check current status */
schedule_delayed_work(&bat_work,
msecs_to_jiffies(JITTER_DELAY));
return 0;
}
#else
#define s3c_adc_bat_suspend NULL
#define s3c_adc_bat_resume NULL
#endif
static struct platform_driver s3c_adc_bat_driver = {
.driver = {
.name = "s3c-adc-battery",
},
.probe = s3c_adc_bat_probe,
.remove = s3c_adc_bat_remove,
.suspend = s3c_adc_bat_suspend,
.resume = s3c_adc_bat_resume,
};
module_platform_driver(s3c_adc_bat_driver);
MODULE_AUTHOR("Vasily Khoruzhick <anarsoul@gmail.com>");
MODULE_DESCRIPTION("iPAQ H1930/H1940/RX1950 battery controller driver");
MODULE_LICENSE("GPL");
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