Re: [PATCH 1/2] power_supply: Charger-Manager: poll battery health innormal state

From: Chanwoo Choi
Date: Mon Mar 19 2012 - 20:55:43 EST


Hi Rafael,

As Mr. Kim Donggeun leaved the company as personal reason, I reply it
about your comment based on following link because I haven't been
included in mailing list.
- https://lkml.org/lkml/2012/2/29/506

On Thursday, March 1, 2012 9:00:02 AM UTC+9, Rafael J. Wysocki wrote:
> On Thursday, February 23, 2012, Donggeun Kim wrote:
> > Charger-Manager needs to check battery health in normal state
> > as well as suspend-to-RAM state.
> > When the battery is fully charged,
> > Charger-Manager needs to determine when the chargers restart charging.
> >
> > This patch allows Charger-Manager to monitor battery health in normal state
> > and handle operation for chargers after battery is fully charged.
> >
> > Signed-off-by: MyungJoo Ham <myungjoo.ham@xxxxxxxxxxx>
> > Signed-off-by: Donggeun Kim <dg77.kim@xxxxxxxxxxx>
> > Signed-off-by: Kyungmin Park <kyungmin.park@xxxxxxxxxxx>
> > ---
> > Documentation/power/charger-manager.txt | 25 ++++-
> > drivers/power/charger-manager.c | 230
+++++++++++++++++++++++++++++++
> > include/linux/power/charger-manager.h | 25 ++++
> > 3 files changed, 279 insertions(+), 1 deletions(-)
> >
> > diff --git a/Documentation/power/charger-manager.txt
b/Documentation/power/charger-manager.txt
> > index fdcca99..47f7fdc 100644
> > --- a/Documentation/power/charger-manager.txt
> > +++ b/Documentation/power/charger-manager.txt
> > @@ -44,6 +44,12 @@ Charger Manager supports the following:
> > Normally, the platform will need to resume and suspend some devices
> > that are used by Charger Manager.
> >
> > +* Support for premature full-battery event handling
> > + If the battery voltage drops by "fullbatt_vchkdrop_uV" after
> > + "fullbatt_vchkdrop_ms" from the full-battery event, the framework
> > + restarts charging. This check is also performed while suspended by
> > + setting wakeup time accordingly and using suspend_again.
> > +
> > 2. Global Charger-Manager Data related with suspend_again
> > ========================================================
> > In order to setup Charger Manager with suspend-again feature
> > @@ -55,7 +61,7 @@ if there are multiple batteries. If there are multiple batteries, the
> > multiple instances of Charger Manager share the same charger_global_desc
> > and it will manage in-suspend monitoring for all instances of Charger Manager.
> >
> > -The user needs to provide all the two entries properly in order to activate
> > +The user needs to provide all the three entries properly in order to activate
> > in-suspend monitoring:
> >
> > struct charger_global_desc {
> > @@ -74,6 +80,11 @@ bool (*rtc_only_wakeup)(void);
> > same struct. If there is any other wakeup source triggered the
> > wakeup, it should return false. If the "rtc" is the only wakeup
> > reason, it should return true.
> > +
> > +bool assume_timer_stops_in_suspend;
> > + : if true, Charger Manager assumes that
> > + the timer (CM uses jiffies as timer) stops during suspend. Then, CM
> > + assumes that the suspend-duration is same as the alarm length.
>
> The description here is not 100% clear to me. Is it supposed to mean
> that if assume_timer_stops_in_suspend is set, the charger manager will assume
> that there won't be timer events while suspended?
>

I think that jiffy timer event isn't happened after entered suspended state.
Please let me know about your opinion.

> > };
> >
> > 3. How to setup suspend_again
> > @@ -111,6 +122,16 @@ enum polling_modes polling_mode;
> > CM_POLL_CHARGING_ONLY: poll this battery if and only if the
> > battery is being charged.
> >
> > +unsigned int fullbatt_vchkdrop_ms;
> > +unsigned int fullbatt_vchkdrop_uV;
> > + : If both have non-zero values, Charger Manager will check the
> > + battery voltage drop fullbatt_vchkdrop_ms after the battery is fully
> > + charged. If the voltage drop is over fullbatt_vchkdrop_uV, Charger
> > + Manager will try to recharge the battery by disabling and enabling
> > + chargers. Recharge with voltage drop condition only (without delay
> > + condition) is needed to be implemented with hardware interrupts from
> > + fuel gauges or charger devices/chips.
> > +
> > unsigned int fullbatt_uV;
> > : If specified with a non-zero value, Charger Manager assumes
> > that the battery is full (capacity = 100) if the battery is not being
> > @@ -122,6 +143,8 @@ unsigned int polling_interval_ms;
> > this battery every polling_interval_ms or more frequently.
> >
> > enum data_source battery_present;
> > + : CM_ASSUME_ALWAYS_TRUE: assume that the battery exists.
>
> I'd call that CM_BATTERY_PRESENT

OK, I will modify it.

>
> > + CM_ASSUME_ALWAYS_FALSE: assume that the battery does not exists.
>
> And that CM_NO_BATTERY

OK.

>
> > CM_FUEL_GAUGE: get battery presence information from fuel gauge.
> > CM_CHARGER_STAT: get battery presence from chargers.
> >
> > diff --git a/drivers/power/charger-manager.c b/drivers/power/charger-manager.c
> > index 88fd971..9ecde4c 100644
> > --- a/drivers/power/charger-manager.c
> > +++ b/drivers/power/charger-manager.c
> > @@ -57,6 +57,12 @@ static bool cm_suspended;
> > static bool cm_rtc_set;
> > static unsigned long cm_suspend_duration_ms;
> >
> > +/* About normal (not suspended) monitoring */
> > +static unsigned long polling_jiffy = ULONG_MAX; /* ULONG_MAX: no polling */
> > +static unsigned long next_polling; /* Next appointed polling time */
> > +static struct workqueue_struct *cm_wq; /* init at driver add */
> > +static struct delayed_work cm_monitor_work; /* init at driver add */
> > +
> > /* Global charger-manager description */
> > static struct charger_global_desc *g_desc; /* init with setup_charger_manager */
> >
> > @@ -71,6 +77,12 @@ static bool is_batt_present(struct charger_manager *cm)
> > int i, ret;
> >
> > switch (cm->desc->battery_present) {
> > + case CM_ASSUME_ALWAYS_TRUE:
> > + present = true;
> > + break;
> > + case CM_ASSUME_ALWAYS_FALSE:
> > + present = false;
>
> You don't have to do preset = false here, because it's false already.
>

OK, I will modify it.

> > + break;
> > case CM_FUEL_GAUGE:
> > ret = cm->fuel_gauge->get_property(cm->fuel_gauge,
> > POWER_SUPPLY_PROP_PRESENT, &val);
> > @@ -282,6 +294,26 @@ static int try_charger_enable(struct charger_manager *cm, bool enable)
> > }
> >
> > /**
> > + * try_charger_restart - Restart charging.
> > + * @cm: the Charger Manager representing the battery.
> > + *
> > + * Restart charging by turning off and on the charger.
> > + */
> > +static int try_charger_restart(struct charger_manager *cm)
> > +{
> > + int err;
> > +
> > + if (cm->emergency_stop)
> > + return -EAGAIN;
> > +
> > + err = try_charger_enable(cm, false);
> > + if (err)
> > + return err;
> > +
> > + return try_charger_enable(cm, true);
> > +}
> > +
> > +/**
> > * uevent_notify - Let users know something has changed.
> > * @cm: the Charger Manager representing the battery.
> > * @event: the event string.
> > @@ -339,6 +371,47 @@ static void uevent_notify(struct charger_manager *cm, const char *event)
> > }
> >
> > /**
> > + * fullbatt_vchk - Check voltage drop some times after "FULL" event.
> > + * @work: the work_struct appointing the function
> > + *
> > + * If a user has designated "fullbatt_vchkdrop_ms/uV" values with
> > + * charger_desc, Charger Manager checks voltage drop after the battery
> > + * "FULL" event. It checks whether the voltage has dropped more than
> > + * fullbatt_vchkdrop_uV by calling this function after fullbatt_vchkrop_ms.
> > + */
> > +static void fullbatt_vchk(struct work_struct *work)
> > +{
> > + struct delayed_work *dwork =
> > + container_of(work, struct delayed_work, work);
>
> There's the to_delayed_work() function for that.

OK, I will modify it.

>
> > + struct charger_manager *cm = container_of(dwork,
> > + struct charger_manager, fullbatt_vchk_work);
> > + struct charger_desc *desc = cm->desc;
> > + int batt_uV, err, diff;
> > +
> > + /* remove the appointment for fullbatt_vchk */
> > + cm->fullbatt_vchk_jiffies_at = 0;
> > +
> > + if (!desc->fullbatt_vchkdrop_uV || !desc->fullbatt_vchkdrop_ms)
> > + return;
> > +
> > + err = get_batt_uV(cm, &batt_uV);
> > + if (err) {
> > + dev_err(cm->dev, "%s: get_batt_uV error(%d).\n", __func__, err);
> > + return;
> > + }
> > +
> > + diff = cm->fullbatt_vchk_uV;
> > + diff -= batt_uV;
> > +
> > + dev_dbg(cm->dev, "VBATT dropped %duV after full-batt.\n", diff);
> > +
> > + if (diff > desc->fullbatt_vchkdrop_uV) {
> > + try_charger_restart(cm);
> > + uevent_notify(cm, "Recharge");
> > + }
> > +}
> > +
> > +/**
> > * _cm_monitor - Monitor the temperature and return true for exceptions.
> > * @cm: the Charger Manager representing the battery.
> > *
> > @@ -395,6 +468,68 @@ static bool cm_monitor(void)
> > return stop;
> > }
> >
> > +/**
> > + * _setup_polling - Setup the next instance of polling.
> > + * @work: work_struct of the function _setup_polling.
> > + */
> > +static void _setup_polling(struct work_struct *work)
> > +{
> > + unsigned long min = ULONG_MAX;
> > + struct charger_manager *cm;
> > + bool keep_polling = false;
> > + unsigned long _next_polling;
> > +
> > + mutex_lock(&cm_list_mtx);
> > +
> > + list_for_each_entry(cm, &cm_list, entry) {
> > + if (is_polling_required(cm) && cm->desc->polling_interval_ms) {
> > + keep_polling = true;
> > +
> > + if (min > cm->desc->polling_interval_ms)
> > + min = cm->desc->polling_interval_ms;
> > + }
> > + }
> > +
> > + polling_jiffy = msecs_to_jiffies(min);
> > + if (polling_jiffy <= CM_JIFFIES_SMALL)
> > + polling_jiffy = CM_JIFFIES_SMALL + 1;
> > +
> > + if (!keep_polling)
> > + polling_jiffy = ULONG_MAX;
> > + if (polling_jiffy == ULONG_MAX)
> > + goto out;
> > +
> > + WARN(cm_wq == NULL, "charger-manager: workqueue not initialized"
> > + ". try it later. %s\n", __func__);
> > +
> > + _next_polling = jiffies + polling_jiffy;
> > +
> > + if (!delayed_work_pending(&cm_monitor_work) ||
> > + (delayed_work_pending(&cm_monitor_work) &&
> > + time_after(next_polling, _next_polling))) {
> > + cancel_delayed_work(&cm_monitor_work);
>
> Shouldn't that be cancel_delayes_work_sync() ?

You're right. When cm_monitor_work isn't pending state,
use cancel_delayed_work_sync() to cancel 'cm_monitor_work'
with running state for waiting completion of callback
of 'cm_monitor_work'.

>
> > + next_polling = jiffies + polling_jiffy;
> > + queue_delayed_work(cm_wq, &cm_monitor_work, polling_jiffy);
> > + }
> > +
> > +out:
> > + mutex_unlock(&cm_list_mtx);
> > +}
> > +static DECLARE_WORK(setup_polling, _setup_polling);
> > +
> > +/**
> > + * cm_monitor_poller - The Monitor / Poller.
> > + * @work: work_struct of the function cm_monitor_poller
> > + *
> > + * During non-suspended state, cm_monitor_poller is used to poll and monitor
> > + * the batteries.
> > + */
> > +static void cm_monitor_poller(struct work_struct *work)
> > +{
> > + cm_monitor();
> > + schedule_work(&setup_polling);
> > +}
> > +
> > static int charger_get_property(struct power_supply *psy,
> > enum power_supply_property psp,
> > union power_supply_propval *val)
> > @@ -616,6 +751,20 @@ static bool cm_setup_timer(void)
> > mutex_lock(&cm_list_mtx);
> >
> > list_for_each_entry(cm, &cm_list, entry) {
> > + unsigned int fbchk_ms = 0;
> > +
> > + /* fullbatt_vchk is required. setup timer for that */
> > + if (cm->fullbatt_vchk_jiffies_at) {
> > + fbchk_ms = jiffies_to_msecs(cm->fullbatt_vchk_jiffies_at
> > + - jiffies);
> > + if (cm->fullbatt_vchk_jiffies_at <= jiffies
>
> time_before_eq_jiffies() ?

OK, I will modify it.

>
> > ||
> > + msecs_to_jiffies(fbchk_ms) < CM_JIFFIES_SMALL) {
> > + fullbatt_vchk(&cm->fullbatt_vchk_work.work);
> > + fbchk_ms = 0;
> > + }
> > + }
> > + CM_MIN_VALID(wakeup_ms, fbchk_ms);
> > +
> > /* Skip if polling is not required for this CM */
> > if (!is_polling_required(cm) && !cm->emergency_stop)
> > continue;
> > @@ -675,6 +824,27 @@ static bool cm_setup_timer(void)
> > return false;
> > }
> >
> > +static bool _cm_fbchk_in_suspend(struct charger_manager *cm)
>
> Why do you need it to return bool?

OK, I will use 'void' type instead of 'bool' type.

>
> > +{
> > + unsigned long jiffy_now = jiffies;
> > +
> > + if (!cm->fullbatt_vchk_jiffies_at)
> > + return false;
> > +
> > + if (g_desc && g_desc->assume_timer_stops_in_suspend)
> > + jiffy_now += msecs_to_jiffies(cm_suspend_duration_ms);
> > +
> > + /* Execute now if it's going to be executed not too long after */
> > + jiffy_now += CM_JIFFIES_SMALL;
> > +
> > + if (time_after_eq(jiffy_now, cm->fullbatt_vchk_jiffies_at)) {
> > + fullbatt_vchk(&cm->fullbatt_vchk_work.work);
> > + return true;
> > + }
> > +
> > + return false;
> > +}
> > +
> > /**
> > * cm_suspend_again - Determine whether suspend again or not
> > *
> > @@ -696,6 +866,8 @@ bool cm_suspend_again(void)
> > ret = true;
> > mutex_lock(&cm_list_mtx);
> > list_for_each_entry(cm, &cm_list, entry) {
> > + _cm_fbchk_in_suspend(cm);
> > +
> > if (cm->status_save_ext_pwr_inserted != is_ext_pwr_online(cm) ||
> > cm->status_save_batt != is_batt_present(cm))
> > ret = false;
> > @@ -797,6 +969,21 @@ static int charger_manager_probe(struct platform_device *pdev)
> > memcpy(cm->desc, desc, sizeof(struct charger_desc));
> > cm->last_temp_mC = INT_MIN; /* denotes "unmeasured, yet" */
> >
> > + /*
> > + * The following two do not need to be errors.
> > + * Users may intentionally ignore those two features.
> > + */
> > + if (desc->fullbatt_uV == 0) {
> > + dev_info(&pdev->dev, "Ignoring full-battery voltage threshold"
> > + " as it is not supplied.");
> > + }
> > + if (!desc->fullbatt_vchkdrop_ms || !desc->fullbatt_vchkdrop_uV) {
> > + dev_info(&pdev->dev, "Disabling full-battery voltage drop "
> > + "checking mechanism as it is not supplied.");
> > + desc->fullbatt_vchkdrop_ms = 0;
> > + desc->fullbatt_vchkdrop_uV = 0;
> > + }
> > +
> > if (!desc->charger_regulators || desc->num_charger_regulators < 1) {
> > ret = -EINVAL;
> > dev_err(&pdev->dev, "charger_regulators undefined.\n");
> > @@ -905,6 +1092,8 @@ static int charger_manager_probe(struct platform_device *pdev)
> > cm->charger_psy.num_properties++;
> > }
> >
> > + INIT_DELAYED_WORK(&cm->fullbatt_vchk_work, fullbatt_vchk);
> > +
> > ret = power_supply_register(NULL, &cm->charger_psy);
> > if (ret) {
> > dev_err(&pdev->dev, "Cannot register charger-manager with"
> > @@ -930,6 +1119,8 @@ static int charger_manager_probe(struct platform_device *pdev)
> > list_add(&cm->entry, &cm_list);
> > mutex_unlock(&cm_list_mtx);
> >
> > + schedule_work(&setup_polling);
> > +
> > return 0;
> >
> > err_chg_enable:
> > @@ -961,10 +1152,14 @@ static int __devexit charger_manager_remove(struct platform_device *pdev)
> > list_del(&cm->entry);
> > mutex_unlock(&cm_list_mtx);
> >
> > + schedule_work(&setup_polling);
> > +
> > if (desc->charger_regulators)
> > regulator_bulk_free(desc->num_charger_regulators,
> > desc->charger_regulators);
> >
> > + try_charger_enable(cm, false);
> > +
> > power_supply_unregister(&cm->charger_psy);
> > kfree(cm->charger_psy.properties);
> > kfree(cm->charger_stat);
> > @@ -1007,6 +1202,7 @@ static int cm_suspend_prepare(struct device *dev)
> > cm_suspended = true;
> > }
> >
> > + cancel_delayed_work(&cm->fullbatt_vchk_work);
>
> Why do you need to cancel it here?

cm->fullbatt_vchk_work check the health state of battery
in normal state, so cm->fullbatt_vchk_work should be
canceled before entering suspend. I will modify below code:

if (delayed_work_pending(&cm->fullbatt_vchk_work)
cancel_delayed_work(&cm->fullbatt_vchk_work);

>
> > cm->status_save_ext_pwr_inserted = is_ext_pwr_online(cm);
> > cm->status_save_batt = is_batt_present(cm);
> >
> > @@ -1036,6 +1232,34 @@ static void cm_suspend_complete(struct device *dev)
> > cm_rtc_set = false;
> > }
> >
> > + /* Re-enqueue delayed work (fullbatt_vchk_work) */
> > + if (cm->fullbatt_vchk_jiffies_at) {
> > + unsigned long delay = 0;
> > + unsigned long now = jiffies;
>
> I'd do
>
> + unsigned long now = jiffies + CM_JIFFIES_SMALL;
>
> which would simplify the code below.
>

OK, I will modify it.

> > +
> > + if (time_after_eq(now + CM_JIFFIES_SMALL,
> > + cm->fullbatt_vchk_jiffies_at)) {
> > + delay = (unsigned long)((long)(now + CM_JIFFIES_SMALL)
> > + - (long)(cm->fullbatt_vchk_jiffies_at));
>
> I don't really think that handles the possible overflow correctly (if you get
> a negative result and then covert it to unsigned long, that still will produce a
> big positive number).

I think that now value is larger than cm->fullbatt_vchk_jiffies_at,
so delay value is always positive value because of checking difference
of between now and cm->fullbatt_vchk_jiffies_at before calculating
delay value.

>
> > + delay = jiffies_to_msecs(delay);
> > + } else {
> > + delay = 0;
> > + }
> > +
> > + /*
> > + * Account for cm_suspend_duration_ms if
> > + * assume_timer_stops_in_suspend is active
> > + */
> > + if (g_desc && g_desc->assume_timer_stops_in_suspend) {
> > + if (delay > cm_suspend_duration_ms)
> > + delay -= cm_suspend_duration_ms;
> > + else
> > + delay = 0;
> > + }
> > +
> > + queue_delayed_work(cm_wq, &cm->fullbatt_vchk_work,
> > + msecs_to_jiffies(delay));
> > + }
> > uevent_notify(cm, NULL);
> > }
> >
> > @@ -1057,12 +1281,18 @@ static struct platform_driver charger_manager_driver = {
> >
> > static int __init charger_manager_init(void)
> > {
> > + cm_wq = create_freezable_workqueue("charger_manager");
> > + INIT_DELAYED_WORK(&cm_monitor_work, cm_monitor_poller);
> > +
> > return platform_driver_register(&charger_manager_driver);
> > }
> > late_initcall(charger_manager_init);
> >
> > static void __exit charger_manager_cleanup(void)
> > {
> > + destroy_workqueue(cm_wq);
> > + cm_wq = NULL;
> > +
> > platform_driver_unregister(&charger_manager_driver);
> > }
> > module_exit(charger_manager_cleanup);
> > diff --git a/include/linux/power/charger-manager.h b/include/linux/power/charger-manager.h
> > index 4f75e53..78b9865 100644
> > --- a/include/linux/power/charger-manager.h
> > +++ b/include/linux/power/charger-manager.h
> > @@ -18,6 +18,8 @@
> > #include <linux/power_supply.h>
> >
> > enum data_source {
> > + CM_ASSUME_ALWAYS_TRUE,
> > + CM_ASSUME_ALWAYS_FALSE,
> > CM_FUEL_GAUGE,
> > CM_CHARGER_STAT,
> > };
> > @@ -38,11 +40,18 @@ enum polling_modes {
> > * rtc_only_wakeup() returning false.
> > * If the RTC given to CM is the only wakeup reason,
> > * rtc_only_wakeup should return true.
> > + * @assume_timer_stops_in_suspend:
> > + * Assume that the jiffy timer stops in suspend-to-RAM.
> > + * When enabled, CM does not rely on jiffies value in
> > + * suspend_again and assumes that jiffies value does not
> > + * change during suspend.
> > */
> > struct charger_global_desc {
> > char *rtc_name;
> >
> > bool (*rtc_only_wakeup)(void);
> > +
> > + bool assume_timer_stops_in_suspend;
> > };
> >
> > /**
> > @@ -50,6 +59,11 @@ struct charger_global_desc {
> > * @psy_name: the name of power-supply-class for charger manager
> > * @polling_mode:
> > * Determine which polling mode will be used
> > + * @fullbatt_vchkdrop_ms:
> > + * @fullbatt_vchkdrop_uV:
> > + * Check voltage drop after the battery is fully charged.
> > + * If it has dropped more than fullbatt_vchkdrop_uV after
> > + * fullbatt_vchkdrop_ms, CM will restart charging.
> > * @fullbatt_uV: voltage in microvolt
> > * If it is not being charged and VBATT >= fullbatt_uV,
> > * it is assumed to be full.
> > @@ -76,6 +90,8 @@ struct charger_desc {
> > enum polling_modes polling_mode;
> > unsigned int polling_interval_ms;
> >
> > + unsigned int fullbatt_vchkdrop_ms;
> > + unsigned int fullbatt_vchkdrop_uV;
> > unsigned int fullbatt_uV;
> >
> > enum data_source battery_present;
> > @@ -101,6 +117,11 @@ struct charger_desc {
> > * @fuel_gauge: power_supply for fuel gauge
> > * @charger_stat: array of power_supply for chargers
> > * @charger_enabled: the state of charger
> > + * @fullbatt_vchk_jiffies_at:
> > + * jiffies at the time full battery check will occur.
> > + * @fullbatt_vchk_uV: voltage in microvolt
> > + * criteria for full battery
> > + * @fullbatt_vchk_work: work queue for full battery check
> > * @emergency_stop:
> > * When setting true, stop charging
> > * @last_temp_mC: the measured temperature in milli-Celsius
> > @@ -121,6 +142,10 @@ struct charger_manager {
> >
> > bool charger_enabled;
> >
> > + unsigned long fullbatt_vchk_jiffies_at;
> > + unsigned int fullbatt_vchk_uV;
> > + struct delayed_work fullbatt_vchk_work;
> > +
> > int emergency_stop;
> > int last_temp_mC;
> >
> >
>
> Thanks,
> Rafael
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Best Regards,
Chanwoo Choi



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