Date:	Tue, 20 Mar 2012 09:55:25 +0900
From:	Chanwoo Choi <cw00.choi@...sung.com>
To:	"Rafael J. Wysocki" <rjw@...k.pl>
Cc:	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	cbouatmailru@...il.com, Len Brown <len.brown@...el.com>,
	pavel@....cz, rdunlap@...otime.net,
	"myungjoo.ham@...sung.com" <myungjoo.ham@...sung.com>,
	Kyungmin Park <kyungmin.park@...sung.com>
Subject: Re: [PATCH 2/2] power_supply: Charger-Manager: provide function for
 in-kernel use

Hi Rafael,

As I said on first patch of this patchset, I reply it based on following
link.
- https://lkml.org/lkml/2012/2/29/524

On Thursday, March 1, 2012 9:10:01 AM UTC+9, Rafael J. Wysocki wrote:
> On Thursday, February 23, 2012, Donggeun Kim wrote:
> > By using cm_notify_event function,
> > charger driver can report several charger events
> > (e.g. battery full and external power in/out, etc) to Charger-Manager.
> > Charger-Manager can properly and immediately control chargers
> > by the reported event.
> >
> > Signed-off-by: MyungJoo Ham <myungjoo.ham@...sung.com>
> > Signed-off-by: Donggeun Kim <dg77.kim@...sung.com>
> > Signed-off-by: Kyungmin Park <kyungmin.park@...sung.com>
> > ---
> >  Documentation/power/charger-manager.txt |   16 +++-
> >  drivers/power/charger-manager.c         |  157 +++++++++++++++++++++++++++++++
> >  include/linux/power/charger-manager.h   |   18 ++++
> >  3 files changed, 190 insertions(+), 1 deletions(-)
> >
> > diff --git a/Documentation/power/charger-manager.txt b/Documentation/power/charger-manager.txt
> > index 47f7fdc..f6566c7 100644
> > --- a/Documentation/power/charger-manager.txt
> > +++ b/Documentation/power/charger-manager.txt
> > @@ -50,6 +50,10 @@ Charger Manager supports the following:
> >  	restarts charging. This check is also performed while suspended by
> >  	setting wakeup time accordingly and using suspend_again.
> >
> > +* Support for uevent-notify
> > +	With the charger-related events, the device sends
> > +	notification to users with UEVENT.
> > +
> >  2. Global Charger-Manager Data related with suspend_again
> >  ========================================================
> >  In order to setup Charger Manager with suspend-again feature
> > @@ -174,7 +178,17 @@ bool measure_battery_temp;
> >  	the value of measure_battery_temp.
> >  };
> >
> > -5. Other Considerations
> > +5. Notify Charger-Manager of charger events: cm_notify_event()
> > +=========================================================
> > +If there is an charger event is required to notify
> > +Charger Manager, a charger device driver that triggers the event can call
> > +cm_notify_event(psy, type, msg) to notify the corresponding Charger Manager.
> > +In the function, psy is the charger driver's power_supply pointer, which is
> > +associated with Charger-Manager. The parameter "type"
> > +is the same as irq's type (enum cm_event_types). The event message "msg" is
> > +optional and is effective only if the event type is "UNDESCRIBED" or "OTHERS".
> > +
> > +6. Other Considerations
> >  =======================
> >
> >  At the charger/battery-related events such as battery-pulled-out,
> > diff --git a/drivers/power/charger-manager.c b/drivers/power/charger-manager.c
> > index 9ecde4c..8cf0d42 100644
> > --- a/drivers/power/charger-manager.c
> > +++ b/drivers/power/charger-manager.c
> > @@ -23,6 +23,16 @@
> >  #include <linux/power/charger-manager.h>
> >  #include <linux/regulator/consumer.h>
> >
> > +static const char * const default_event_names[] = {
> > +	[CM_EVENT_UNDESCRIBED] = "Undescribed",
>
> "Unknown" perhaps?

OK, I will modify it.

>
> > +	[CM_EVENT_BATT_FULL] = "Battery Full",
> > +	[CM_EVENT_BATT_IN] = "Battery Inserted",
> > +	[CM_EVENT_BATT_OUT] = "Battery Pulled Out",
> > +	[CM_EVENT_EXT_PWR_IN_OUT] = "External Power Attach/Detach",
> > +	[CM_EVENT_CHG_START_STOP] = "Charging Start/Stop",
> > +	[CM_EVENT_OTHERS] = "Other battery events"
> > +};
> > +
> >  /*
> >   * Regard CM_JIFFIES_SMALL jiffies is small enough to ignore for
> >   * delayed works so that we can run delayed works with CM_JIFFIES_SMALL
> > @@ -530,6 +540,68 @@ static void cm_monitor_poller(struct work_struct *work)
> >  	schedule_work(&setup_polling);
> >  }
> >
> > +/**
> > + * fullbatt_handler - Event handler for CM_EVENT_BATT_FULL
> > + * @cm: the Charger Manager representing the battery.
> > + */
> > +static void fullbatt_handler(struct charger_manager *cm)
> > +{
> > +	struct charger_desc *desc = cm->desc;
> > +
> > +	if (!desc->fullbatt_vchkdrop_uV || !desc->fullbatt_vchkdrop_ms)
> > +		goto out;
> > +
> > +	if (cm_suspended)
> > +		cm->cancel_suspend = true;
> > +
> > +	cancel_delayed_work(&cm->fullbatt_vchk_work);
>
> Is cancel_delayed_work() sufficient here?

I will modify it as code below. When CM_EVENT_BATT_FULL is occured,
cm should cancel cm->fullbatt_vchk_work if cm->fullbatt_vchk_work is
pending state.

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

> > +	queue_delayed_work(cm_wq, &cm->fullbatt_vchk_work,
> > +			   msecs_to_jiffies(desc->fullbatt_vchkdrop_ms));
> > +	cm->fullbatt_vchk_jiffies_at = jiffies + msecs_to_jiffies(
> > +				       desc->fullbatt_vchkdrop_ms);
> > +
> > +	if (cm->fullbatt_vchk_jiffies_at == 0)
> > +		cm->fullbatt_vchk_jiffies_at = 1;
> > +
> > +out:
> > +	dev_info(cm->dev, "EVENT_HANDLE: Battery Fully Charged.\n");
> > +	uevent_notify(cm, default_event_names[CM_EVENT_BATT_FULL]);
> > +}
> > +
> > +/**
> > + * battout_handler - Event handler for CM_EVENT_BATT_OUT
> > + * @cm: the Charger Manager representing the battery.
> > + */
> > +static void battout_handler(struct charger_manager *cm)
> > +{
> > +	if (cm_suspended)
> > +		cm->cancel_suspend = true;
> > +
> > +	if (!is_batt_present(cm)) {
> > +		dev_emerg(cm->dev, "Battery Pulled Out!\n");
> > +		uevent_notify(cm, default_event_names[CM_EVENT_BATT_OUT]);
> > +	} else {
> > +		uevent_notify(cm, "Battery Reinserted?");
> > +	}
> > +}
> > +
> > +/**
> > + * misc_event_handler - Handler for other evnets
> > + * @cm: the Charger Manager representing the battery.
> > + * @type: the Charger Manager representing the battery.
> > + */
> > +static void misc_event_handler(struct charger_manager *cm,
> > +			enum cm_event_types type)
> > +{
> > +	if (cm_suspended)
> > +		cm->cancel_suspend = true;
> > +
> > +	if (!delayed_work_pending(&cm_monitor_work) &&
> > +	    is_polling_required(cm) && cm->desc->polling_interval_ms)
> > +		schedule_work(&setup_polling);
> > +	uevent_notify(cm, default_event_names[type]);
> > +}
> > +
> >  static int charger_get_property(struct power_supply *psy,
> >  		enum power_supply_property psp,
> >  		union power_supply_propval *val)
> > @@ -1175,6 +1247,20 @@ static const struct platform_device_id charger_manager_id[] = {
> >  };
> >  MODULE_DEVICE_TABLE(platform, charger_manager_id);
> >
> > +static int cm_suspend_noirq(struct device *dev)
> > +{
> > +	struct platform_device *pdev = container_of(dev, struct platform_device,
> > +						    dev);
> > +	struct charger_manager *cm = platform_get_drvdata(pdev);
> > +
> > +	if (cm->cancel_suspend) {
> > +		cm->cancel_suspend = false;
> > +		return -EAGAIN;
> > +	}
> > +
> > +	return 0;
> > +}
> > +
> >  static int cm_suspend_prepare(struct device *dev)
> >  {
> >  	struct platform_device *pdev = container_of(dev, struct platform_device,
> > @@ -1260,11 +1346,13 @@ static void cm_suspend_complete(struct device *dev)
> >  		queue_delayed_work(cm_wq, &cm->fullbatt_vchk_work,
> >  				   msecs_to_jiffies(delay));
> >  	}
> > +	cm->cancel_suspend = false;
> >  	uevent_notify(cm, NULL);
> >  }
> >
> >  static const struct dev_pm_ops charger_manager_pm = {
> >  	.prepare	= cm_suspend_prepare,
> > +	.suspend_noirq	= cm_suspend_noirq,
> >  	.complete	= cm_suspend_complete,
> >  };
> >
> > @@ -1297,6 +1385,75 @@ static void __exit charger_manager_cleanup(void)
> >  }
> >  module_exit(charger_manager_cleanup);
> >
> > +/**
> > + * find_power_supply - find the associated power_supply of charger
> > + * @cm: the Charger Manager representing the battery
> > + * @psy: pointer to instance of charger's power_supply
> > + */
> > +static bool find_power_supply(struct charger_manager *cm,
> > +			struct power_supply *psy)
> > +{
> > +	int i;
> > +	bool found = false;
> > +
> > +	for (i = 0; cm->charger_stat[i]; i++) {
> > +		if (psy == cm->charger_stat[i]) {
> > +			found = true;
> > +			break;
> > +		}
> > +	}
> > +
> > +	return found;
> > +}
> > +
> > +/**
> > + * cm_notify_event - charger driver notify Charger Manager of charger event
> > + * @psy: pointer to instance of charger's power_supply
> > + * @type: type of charger event
> > + * @msg: optional message passed to uevent_notify fuction
> > + */
> > +void cm_notify_event(struct power_supply *psy, enum cm_event_types type,
> > +		     char *msg)
> > +{
> > +	struct charger_manager *cm;
> > +	bool found_power_supply = false;
> > +
> > +	if (psy == NULL)
> > +		return;
> > +
> > +	mutex_lock(&cm_list_mtx);
> > +	list_for_each_entry(cm, &cm_list, entry) {
> > +		found_power_supply = find_power_supply(cm, psy);
> > +		if (found_power_supply)
> > +			break;
> > +	}
> > +	mutex_unlock(&cm_list_mtx);
>
> Why don't you move the entire loop above to find_power_supply()?
> You won't need the found_power_supply variable in that case.

This code check whether *psy parameter is included in charger-manager of
cm_list which make possible include the number of charger-manger.
If psy isn't included in some charger-manager, cm_notify_event
immediately returns without operation.

>
> > +	if (!found_power_supply)
> > +		return;
> > +
> > +	switch (type) {
> > +	case CM_EVENT_BATT_FULL:
> > +		fullbatt_handler(cm);
> > +		break;
> > +	case CM_EVENT_BATT_OUT:
> > +		battout_handler(cm);
> > +		break;
> > +	case CM_EVENT_BATT_IN:
> > +	case CM_EVENT_EXT_PWR_IN_OUT ... CM_EVENT_CHG_START_STOP:
> > +		misc_event_handler(cm, type);
> > +		break;
> > +	case CM_EVENT_UNDESCRIBED:
> > +	case CM_EVENT_OTHERS:
> > +		uevent_notify(cm, msg ? msg : default_event_names[type]);
> > +		break;
> > +	default:
> > +		dev_err(cm->dev, "%s type not specified.\n", __func__);
> > +		break;
> > +	}
> > +}
> > +EXPORT_SYMBOL_GPL(cm_notify_event);
> > +
> >  MODULE_AUTHOR("MyungJoo Ham <myungjoo.ham@...sung.com>");
> >  MODULE_DESCRIPTION("Charger Manager");
> >  MODULE_LICENSE("GPL");
> > diff --git a/include/linux/power/charger-manager.h b/include/linux/power/charger-manager.h
> > index 78b9865..086917c 100644
> > --- a/include/linux/power/charger-manager.h
> > +++ b/include/linux/power/charger-manager.h
> > @@ -31,6 +31,16 @@ enum polling_modes {
> >  	CM_POLL_CHARGING_ONLY,
> >  };
> >
> > +enum cm_event_types {
> > +	CM_EVENT_UNDESCRIBED = 0,
> > +	CM_EVENT_BATT_FULL,
> > +	CM_EVENT_BATT_IN,
> > +	CM_EVENT_BATT_OUT,
> > +	CM_EVENT_EXT_PWR_IN_OUT,
> > +	CM_EVENT_CHG_START_STOP,
> > +	CM_EVENT_OTHERS,
> > +};
> > +
> >  /**
> >   * struct charger_global_desc
> >   * @rtc_name: the name of RTC used to wake up the system from suspend.
> > @@ -116,6 +126,7 @@ struct charger_desc {
> >   * @desc: instance of charger_desc
> >   * @fuel_gauge: power_supply for fuel gauge
> >   * @charger_stat: array of power_supply for chargers
> > + * @cancel_suspend: true if there is a pending charger event
> >   * @charger_enabled: the state of charger
> >   * @fullbatt_vchk_jiffies_at:
> >   *	jiffies at the time full battery check will occur.
> > @@ -140,6 +151,7 @@ struct charger_manager {
> >  	struct power_supply *fuel_gauge;
> >  	struct power_supply **charger_stat;
> >
> > +	bool cancel_suspend;
> >  	bool charger_enabled;
> >
> >  	unsigned long fullbatt_vchk_jiffies_at;
> > @@ -159,6 +171,8 @@ struct charger_manager {
> >  #ifdef CONFIG_CHARGER_MANAGER
> >  extern int setup_charger_manager(struct charger_global_desc *gd);
> >  extern bool cm_suspend_again(void);
> > +extern void cm_notify_event(struct power_supply *psy, enum cm_event_types type,
> > +			    char *msg); /* msg: optional */
> >  #else
> >  static void __maybe_unused setup_charger_manager(struct charger_global_desc *gd)
> >  { }
> > @@ -167,6 +181,10 @@ static bool __maybe_unused cm_suspend_again(void)
> >  {
> >  	return false;
> >  }
> > +
> > +static void __maybe_unused cm_notify_event(struct power_supply *psy,
> > +					   enum cm_event_types type, char *msg)
> > +{ }
>
> We usually define such things as static inline, in which case the __maybe_unused
> is not necessary.
>

OK, I will fix it.

> >  #endif
> >
> >  #endif /* _CHARGER_MANAGER_H */
> >
>
> Thanks,
> Rafael
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Best Regards,
Chanwoo Choi

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