linux-hardened/drivers/power/power_supply_leds.c
Krzysztof Kozlowski a9f6a19b57 power_supply: Use wrappers to avoid races when registering power supply
Use wrappers over get_property() and set_property() internally in power
supply and for sysfs interface. The wrappers provide safe access if
power supply is not yet registered or t is being destroyed.

In case of syfs the theoretical race could happen between ending of
driver's probe and parallel sysfs access:
some_driver_probe()                    userspace
====================================   ===========================
  drv->psy = power_supply_register()
    device_add()
      sysfs entries are created
    atomic_inc(&psy->use_cnt);
                                       store on sysfs attributes
                                         drv->set_property()
                                           dereference of drv->psy
  drv->psy = returned psy;

For leds the race could happen between power supply being destroyed and
ongoing power_supply_changed_work().

Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Signed-off-by: Sebastian Reichel <sre@kernel.org>
2015-05-23 20:06:19 +02:00

170 lines
4.8 KiB
C

/*
* LEDs triggers for power supply class
*
* Copyright © 2007 Anton Vorontsov <cbou@mail.ru>
* Copyright © 2004 Szabolcs Gyurko
* Copyright © 2003 Ian Molton <spyro@f2s.com>
*
* Modified: 2004, Oct Szabolcs Gyurko
*
* You may use this code as per GPL version 2
*/
#include <linux/kernel.h>
#include <linux/device.h>
#include <linux/power_supply.h>
#include <linux/slab.h>
#include "power_supply.h"
/* Battery specific LEDs triggers. */
static void power_supply_update_bat_leds(struct power_supply *psy)
{
union power_supply_propval status;
unsigned long delay_on = 0;
unsigned long delay_off = 0;
if (power_supply_get_property(psy, POWER_SUPPLY_PROP_STATUS, &status))
return;
dev_dbg(&psy->dev, "%s %d\n", __func__, status.intval);
switch (status.intval) {
case POWER_SUPPLY_STATUS_FULL:
led_trigger_event(psy->charging_full_trig, LED_FULL);
led_trigger_event(psy->charging_trig, LED_OFF);
led_trigger_event(psy->full_trig, LED_FULL);
led_trigger_event(psy->charging_blink_full_solid_trig,
LED_FULL);
break;
case POWER_SUPPLY_STATUS_CHARGING:
led_trigger_event(psy->charging_full_trig, LED_FULL);
led_trigger_event(psy->charging_trig, LED_FULL);
led_trigger_event(psy->full_trig, LED_OFF);
led_trigger_blink(psy->charging_blink_full_solid_trig,
&delay_on, &delay_off);
break;
default:
led_trigger_event(psy->charging_full_trig, LED_OFF);
led_trigger_event(psy->charging_trig, LED_OFF);
led_trigger_event(psy->full_trig, LED_OFF);
led_trigger_event(psy->charging_blink_full_solid_trig,
LED_OFF);
break;
}
}
static int power_supply_create_bat_triggers(struct power_supply *psy)
{
psy->charging_full_trig_name = kasprintf(GFP_KERNEL,
"%s-charging-or-full", psy->desc->name);
if (!psy->charging_full_trig_name)
goto charging_full_failed;
psy->charging_trig_name = kasprintf(GFP_KERNEL,
"%s-charging", psy->desc->name);
if (!psy->charging_trig_name)
goto charging_failed;
psy->full_trig_name = kasprintf(GFP_KERNEL, "%s-full", psy->desc->name);
if (!psy->full_trig_name)
goto full_failed;
psy->charging_blink_full_solid_trig_name = kasprintf(GFP_KERNEL,
"%s-charging-blink-full-solid", psy->desc->name);
if (!psy->charging_blink_full_solid_trig_name)
goto charging_blink_full_solid_failed;
led_trigger_register_simple(psy->charging_full_trig_name,
&psy->charging_full_trig);
led_trigger_register_simple(psy->charging_trig_name,
&psy->charging_trig);
led_trigger_register_simple(psy->full_trig_name,
&psy->full_trig);
led_trigger_register_simple(psy->charging_blink_full_solid_trig_name,
&psy->charging_blink_full_solid_trig);
return 0;
charging_blink_full_solid_failed:
kfree(psy->full_trig_name);
full_failed:
kfree(psy->charging_trig_name);
charging_failed:
kfree(psy->charging_full_trig_name);
charging_full_failed:
return -ENOMEM;
}
static void power_supply_remove_bat_triggers(struct power_supply *psy)
{
led_trigger_unregister_simple(psy->charging_full_trig);
led_trigger_unregister_simple(psy->charging_trig);
led_trigger_unregister_simple(psy->full_trig);
led_trigger_unregister_simple(psy->charging_blink_full_solid_trig);
kfree(psy->charging_blink_full_solid_trig_name);
kfree(psy->full_trig_name);
kfree(psy->charging_trig_name);
kfree(psy->charging_full_trig_name);
}
/* Generated power specific LEDs triggers. */
static void power_supply_update_gen_leds(struct power_supply *psy)
{
union power_supply_propval online;
if (power_supply_get_property(psy, POWER_SUPPLY_PROP_ONLINE, &online))
return;
dev_dbg(&psy->dev, "%s %d\n", __func__, online.intval);
if (online.intval)
led_trigger_event(psy->online_trig, LED_FULL);
else
led_trigger_event(psy->online_trig, LED_OFF);
}
static int power_supply_create_gen_triggers(struct power_supply *psy)
{
psy->online_trig_name = kasprintf(GFP_KERNEL, "%s-online",
psy->desc->name);
if (!psy->online_trig_name)
return -ENOMEM;
led_trigger_register_simple(psy->online_trig_name, &psy->online_trig);
return 0;
}
static void power_supply_remove_gen_triggers(struct power_supply *psy)
{
led_trigger_unregister_simple(psy->online_trig);
kfree(psy->online_trig_name);
}
/* Choice what triggers to create&update. */
void power_supply_update_leds(struct power_supply *psy)
{
if (psy->desc->type == POWER_SUPPLY_TYPE_BATTERY)
power_supply_update_bat_leds(psy);
else
power_supply_update_gen_leds(psy);
}
int power_supply_create_triggers(struct power_supply *psy)
{
if (psy->desc->type == POWER_SUPPLY_TYPE_BATTERY)
return power_supply_create_bat_triggers(psy);
return power_supply_create_gen_triggers(psy);
}
void power_supply_remove_triggers(struct power_supply *psy)
{
if (psy->desc->type == POWER_SUPPLY_TYPE_BATTERY)
power_supply_remove_bat_triggers(psy);
else
power_supply_remove_gen_triggers(psy);
}