Re: [PATCH 52/57] power: abx500_chargalg: Use hrtimer

[Anton Vorontsov <anton.vorontsov@linaro.org>]

On Tue, Sep 25, 2012 at 10:12:49AM -0600, mathieu.poirier@linaro.org wrote:
> From: Hakan Berg <hakan.berg@stericsson.com>
> 
> Timers used for charging safety and maintenance must work even when
> CPU is power collapsed. By using hrtimers with realtime clock, system
> is able to trigger an alarm that wakes the CPU up and make it possible
> to handle the event.
> 
> Allow a little slack of 5 minutes to the hrtimers to allow CPU to be
> waked up in a more optimal power saving way. A 5 minute delay to
> time out timers on hours does not impact on safety.
> 
> Signed-off-by: Hakan Berg <hakan.berg@stericsson.com>
> Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
> Reviewed-by: Mian Yousaf KAUKAB <mian.yousaf.kaukab@stericsson.com>
> ---
>  drivers/power/abx500_chargalg.c |   94 ++++++++++++++++++++++-----------------
>  1 files changed, 53 insertions(+), 41 deletions(-)
> 
> diff --git a/drivers/power/abx500_chargalg.c b/drivers/power/abx500_chargalg.c
> index 636d970..c8849af 100644
> --- a/drivers/power/abx500_chargalg.c
> +++ b/drivers/power/abx500_chargalg.c
> @@ -1,5 +1,6 @@
>  /*
>   * Copyright (C) ST-Ericsson SA 2012
> + * Copyright (c) 2012 Sony Mobile Communications AB
>   *
>   * Charging algorithm driver for abx500 variants
>   *
> @@ -8,11 +9,13 @@
>   *	Johan Palsson <johan.palsson@stericsson.com>
>   *	Karl Komierowski <karl.komierowski@stericsson.com>
>   *	Arun R Murthy <arun.murthy@stericsson.com>
> + *	Imre Sunyi <imre.sunyi@sonymobile.com>
>   */
>  
>  #include <linux/init.h>
>  #include <linux/module.h>
>  #include <linux/device.h>
> +#include <linux/hrtimer.h>
>  #include <linux/interrupt.h>
>  #include <linux/delay.h>
>  #include <linux/slab.h>
> @@ -32,6 +35,12 @@
>  /* End-of-charge criteria counter */
>  #define EOC_COND_CNT			10
>  
> +/* One hour expressed in seconds */
> +#define ONE_HOUR_IN_SECONDS		3600
> +
> +/* Five minutes expressed in seconds */
> +#define FIVE_MINUTES_IN_SECONDS		300
> +
>  #define to_abx500_chargalg_device_info(x) container_of((x), \
>  	struct abx500_chargalg, chargalg_psy);
>  
> @@ -245,8 +254,8 @@ struct abx500_chargalg {
>  	struct delayed_work chargalg_periodic_work;
>  	struct delayed_work chargalg_wd_work;
>  	struct work_struct chargalg_work;
> -	struct timer_list safety_timer;
> -	struct timer_list maintenance_timer;
> +	struct hrtimer safety_timer;
> +	struct hrtimer maintenance_timer;
>  	struct kobject chargalg_kobject;
>  };
>  
> @@ -261,38 +270,47 @@ BLOCKING_NOTIFIER_HEAD(charger_notifier_list);
>  
>  /**
>   * abx500_chargalg_safety_timer_expired() - Expiration of the safety timer
> - * @data:	pointer to the abx500_chargalg structure
> + * @timer:	pointer to the hrtimer structure
>   *
>   * This function gets called when the safety timer for the charger
>   * expires
>   */
> -static void abx500_chargalg_safety_timer_expired(unsigned long data)
> +static enum hrtimer_restart
> +abx500_chargalg_safety_timer_expired(struct hrtimer *timer)
>  {
> -	struct abx500_chargalg *di = (struct abx500_chargalg *) data;
> +	struct abx500_chargalg *di = container_of(timer, struct abx500_chargalg,
> +							safety_timer);

Empty line here.

>  	dev_err(di->dev, "Safety timer expired\n");
>  	di->events.safety_timer_expired = true;
>  
>  	/* Trigger execution of the algorithm instantly */
>  	queue_work(di->chargalg_wq, &di->chargalg_work);
> +
> +	return HRTIMER_NORESTART;
>  }
>  
>  /**
>   * abx500_chargalg_maintenance_timer_expired() - Expiration of
>   * the maintenance timer
> - * @i:		pointer to the abx500_chargalg structure
> + * @timer:	pointer to the timer structure
>   *
>   * This function gets called when the maintenence timer
>   * expires
>   */
> -static void abx500_chargalg_maintenance_timer_expired(unsigned long data)
> +static enum hrtimer_restart
> +abx500_chargalg_maintenance_timer_expired(struct hrtimer *timer)
> +
>  {
>  
> -	struct abx500_chargalg *di = (struct abx500_chargalg *) data;
> +	struct abx500_chargalg *di = container_of(timer, struct abx500_chargalg,
> +							maintenance_timer);
>  	dev_dbg(di->dev, "Maintenance timer expired\n");
>  	di->events.maintenance_timer_expired = true;
>  
>  	/* Trigger execution of the algorithm instantly */
>  	queue_work(di->chargalg_wq, &di->chargalg_work);
> +
> +	return HRTIMER_NORESTART;
>  }
>  
>  /**
> @@ -392,19 +410,16 @@ static int abx500_chargalg_check_charger_connection(struct abx500_chargalg *di)
>   */
>  static void abx500_chargalg_start_safety_timer(struct abx500_chargalg *di)
>  {
> -	unsigned long timer_expiration = 0;
> +	/* Charger-dependent expiration time in hours*/
> +	int timer_expiration = 0;
>  
>  	switch (di->chg_info.charger_type) {
>  	case AC_CHG:
> -		timer_expiration =
> -		round_jiffies(jiffies +
> -			(di->bat->main_safety_tmr_h * 3600 * HZ));
> +		timer_expiration = di->bat->main_safety_tmr_h;
>  		break;
>  
>  	case USB_CHG:
> -		timer_expiration =
> -		round_jiffies(jiffies +
> -			(di->bat->usb_safety_tmr_h * 3600 * HZ));
> +		timer_expiration = di->bat->usb_safety_tmr_h;
>  		break;
>  
>  	default:
> @@ -413,11 +428,10 @@ static void abx500_chargalg_start_safety_timer(struct abx500_chargalg *di)
>  	}
>  
>  	di->events.safety_timer_expired = false;
> -	di->safety_timer.expires = timer_expiration;
> -	if (!timer_pending(&di->safety_timer))
> -		add_timer(&di->safety_timer);
> -	else
> -		mod_timer(&di->safety_timer, timer_expiration);
> +	hrtimer_set_expires_range(&di->safety_timer,
> +		ktime_set(timer_expiration * ONE_HOUR_IN_SECONDS, 0),
> +		ktime_set(FIVE_MINUTES_IN_SECONDS, 0));
> +	hrtimer_start_expires(&di->safety_timer, HRTIMER_MODE_REL);

OK, now we're chaning from timers to hrtimers, and their behaviour
might be different. I guess in this case you should check whether
old value 'before' new value, and if so, do nothing.

>  }
>  
>  /**
> @@ -428,8 +442,8 @@ static void abx500_chargalg_start_safety_timer(struct abx500_chargalg *di)
>   */
>  static void abx500_chargalg_stop_safety_timer(struct abx500_chargalg *di)
>  {
> -	di->events.safety_timer_expired = false;
> -	del_timer(&di->safety_timer);
> +	if (hrtimer_try_to_cancel(&di->safety_timer) >= 0)
> +		di->events.safety_timer_expired = false;
>  }
>  
>  /**
> @@ -444,17 +458,11 @@ static void abx500_chargalg_stop_safety_timer(struct abx500_chargalg *di)
>  static void abx500_chargalg_start_maintenance_timer(struct abx500_chargalg *di,
>  	int duration)
>  {
> -	unsigned long timer_expiration;
> -
> -	/* Convert from hours to jiffies */
> -	timer_expiration = round_jiffies(jiffies + (duration * 3600 * HZ));
> -
> +	hrtimer_set_expires_range(&di->maintenance_timer,
> +		ktime_set(duration * ONE_HOUR_IN_SECONDS, 0),
> +		ktime_set(FIVE_MINUTES_IN_SECONDS, 0));
>  	di->events.maintenance_timer_expired = false;
> -	di->maintenance_timer.expires = timer_expiration;
> -	if (!timer_pending(&di->maintenance_timer))
> -		add_timer(&di->maintenance_timer);
> -	else
> -		mod_timer(&di->maintenance_timer, timer_expiration);
> +	hrtimer_start_expires(&di->maintenance_timer, HRTIMER_MODE_REL);
>  }
>  
>  /**
> @@ -466,8 +474,8 @@ static void abx500_chargalg_start_maintenance_timer(struct abx500_chargalg *di,
>   */
>  static void abx500_chargalg_stop_maintenance_timer(struct abx500_chargalg *di)
>  {
> -	di->events.maintenance_timer_expired = false;
> -	del_timer(&di->maintenance_timer);
> +	if (hrtimer_try_to_cancel(&di->maintenance_timer) >= 0)
> +		di->events.maintenance_timer_expired = false;
>  }
>  
>  /**
> @@ -910,11 +918,11 @@ static void abx500_chargalg_check_safety_timer(struct abx500_chargalg *di)
>  	 * and charging will be stopped to protect the battery.
>  	 */
>  	if (di->batt_data.percent == 100 &&
> -		!timer_pending(&di->safety_timer)) {
> +		!hrtimer_active(&di->safety_timer)) {
>  		abx500_chargalg_start_safety_timer(di);
>  		dev_dbg(di->dev, "start safety timer\n");
>  	} else if (di->batt_data.percent != 100 &&
> -		timer_pending(&di->safety_timer)) {
> +		hrtimer_active(&di->safety_timer)) {
>  		abx500_chargalg_stop_safety_timer(di);
>  		dev_dbg(di->dev, "stop safety timer\n");
>  	}
> @@ -1932,10 +1940,16 @@ static int __devexit abx500_chargalg_remove(struct platform_device *pdev)
>  	/* sysfs interface to enable/disbale charging from user space */
>  	abx500_chargalg_sysfs_exit(di);
>  
> +	hrtimer_cancel(&di->safety_timer);
> +	hrtimer_cancel(&di->maintenance_timer);
> +
> +	cancel_delayed_work_sync(&di->chargalg_periodic_work);
> +	cancel_delayed_work_sync(&di->chargalg_wd_work);
> +	cancel_work_sync(&di->chargalg_work);
> +

These cancel_ calls seem to be separate bugfixes?

>  	/* Delete the work queue */
>  	destroy_workqueue(di->chargalg_wq);
>  
> -	flush_scheduled_work();
>  	power_supply_unregister(&di->chargalg_psy);
>  	platform_set_drvdata(pdev, NULL);
>  	kfree(di);
> @@ -1987,15 +2001,13 @@ static int __devinit abx500_chargalg_probe(struct platform_device *pdev)
>  		abx500_chargalg_external_power_changed;
>  
>  	/* Initilialize safety timer */
> -	init_timer(&di->safety_timer);
> +	hrtimer_init(&di->safety_timer, CLOCK_REALTIME, HRTIMER_MODE_ABS);
>  	di->safety_timer.function = abx500_chargalg_safety_timer_expired;
> -	di->safety_timer.data = (unsigned long) di;
>  
>  	/* Initilialize maintenance timer */
> -	init_timer(&di->maintenance_timer);
> +	hrtimer_init(&di->maintenance_timer, CLOCK_REALTIME, HRTIMER_MODE_ABS);
>  	di->maintenance_timer.function =
>  		abx500_chargalg_maintenance_timer_expired;
> -	di->maintenance_timer.data = (unsigned long) di;
>  
>  	/* Create a work queue for the chargalg */
>  	di->chargalg_wq =
> -- 
> 1.7.5.4