Date:	Thu, 1 Mar 2012 01:13:11 +0100
From:	"Rafael J. Wysocki" <rjw@...k.pl>
To:	Donggeun Kim <dg77.kim@...sung.com>
Cc:	linux-kernel@...r.kernel.org, cbouatmailru@...il.com,
	len.brown@...el.com, pavel@....cz, rdunlap@...otime.net,
	myungjoo.ham@...sung.com, kyungmin.park@...sung.com
Subject: Re: [PATCH 2/2] power_supply: Charger-Manager: provide function for in-kernel use

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?

> +	[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?

> +	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.

> +	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.

>  #endif
>  
>  #endif /* _CHARGER_MANAGER_H */
> 

Thanks,
Rafael
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