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Date: Thu, 27 Sep 2012 19:47:47 -0700
From: Anton Vorontsov <anton.vorontsov@...aro.org>
To: mathieu.poirier@...aro.org
Cc: linux-kernel@...r.kernel.org, dwmw2@...radead.org
Subject: Re: [PATCH 52/57] power: abx500_chargalg: Use hrtimer
On Tue, Sep 25, 2012 at 10:12:49AM -0600, mathieu.poirier@...aro.org wrote:
> From: Hakan Berg <hakan.berg@...ricsson.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@...ricsson.com>
> Signed-off-by: Mathieu Poirier <mathieu.poirier@...aro.org>
> Reviewed-by: Mian Yousaf KAUKAB <mian.yousaf.kaukab@...ricsson.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@...ricsson.com>
> * Karl Komierowski <karl.komierowski@...ricsson.com>
> * Arun R Murthy <arun.murthy@...ricsson.com>
> + * Imre Sunyi <imre.sunyi@...ymobile.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
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