From: j.anaszewski@samsung•com (Jacek Anaszewski)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH 1/5] leds: triggers: Allow to switch the trigger to "panic" on a kernel panic
Date: Mon, 25 Apr 2016 08:56:46 +0200 [thread overview]
Message-ID: <571DBFAE.7060605@samsung.com> (raw)
In-Reply-To: <20160424092951.GA25596@amd>
On 04/24/2016 11:29 AM, Pavel Machek wrote:
> On Sun 2016-04-24 11:25:51, Pavel Machek wrote:
>> On Mon 2016-04-04 17:22:02, Ezequiel Garcia wrote:
>>> This commit adds a new led_cdev flag LED_BLINK_AT_PANIC, which
>>> allows to mark a specific LED to be switched to the "panic"
>>> trigger, on a kernel panic.
>>>
>>> This is useful to allow the user to assign a regular trigger
>>> to a given LED, and still blink that LED on a kernel panic.
>>>
>>> Signed-off-by: Ezequiel Garcia <ezequiel@vanguardiasur•com.ar>
>>
>>
>>> drivers/leds/led-triggers.c | 52 +++++++++++++++++++++++++++++++++++++++++++++
>>> include/linux/leds.h | 1 +
>>
>> Could we get this out of the core? I'm pretty sure most users are not
>> interested...
Good point.
> Thinking about it some more....
>
> This is not really a trigger. This is very special. Maybe hard-coded
> handling, like we do for keyboard leds on x86 would be suitable?
Could you please spot the piece of code you have on mind?
>
>
>>
>> Pavel
>>
>>> +/*
>>> + * This is a called in a special context by the atomic panic
>>> + * notifier. This means the trigger can be changed without
>>> + * worrying about locking.
>>> + */
>>> +static void led_trigger_set_panic(struct led_classdev *led_cdev)
>>> +{
>>> + struct led_trigger *trig;
>>> +
>>> + list_for_each_entry(trig, &trigger_list, next_trig) {
>>> + if (strcmp("panic", trig->name))
>>> + continue;
>>> + if (led_cdev->trigger)
>>> + list_del(&led_cdev->trig_list);
>>> + list_add_tail(&led_cdev->trig_list, &trig->led_cdevs);
>>> + led_cdev->trigger = trig;
>>> + if (trig->activate)
>>> + trig->activate(led_cdev);
>>> + break;
>>> + }
>>> +}
>>> +
>>> +static int led_trigger_panic_notifier(struct notifier_block *nb,
>>> + unsigned long code, void *unused)
>>> +{
>>> + struct led_classdev *led_cdev;
>>> +
>>> + list_for_each_entry(led_cdev, &leds_list, node)
>>> + if (led_cdev->flags & LED_BLINK_AT_PANIC)
>>> + led_trigger_set_panic(led_cdev);
>>> + return NOTIFY_DONE;
>>> +}
>>> +
>>> +static struct notifier_block led_trigger_panic_nb = {
>>> + .notifier_call = led_trigger_panic_notifier,
>>> +};
>>> +
>>> void led_trigger_set_default(struct led_classdev *led_cdev)
>>> {
>>> struct led_trigger *trig;
>>> @@ -356,6 +393,21 @@ void led_trigger_unregister_simple(struct led_trigger *trig)
>>> }
>>> EXPORT_SYMBOL_GPL(led_trigger_unregister_simple);
>>>
>>> +static int __init leds_trigger_init(void)
>>> +{
>>> + atomic_notifier_chain_register(&panic_notifier_list,
>>> + &led_trigger_panic_nb);
>>> + return 0;
>>> +}
>>> +
>>> +static void __exit leds_trigger_exit(void)
>>> +{
>>> + atomic_notifier_chain_unregister(&panic_notifier_list,
>>> + &led_trigger_panic_nb);
>>> +}
>>> +module_init(leds_trigger_init);
>>> +module_exit(leds_trigger_exit);
>>> +
>>> MODULE_AUTHOR("Richard Purdie");
>>> MODULE_LICENSE("GPL");
>>> MODULE_DESCRIPTION("LED Triggers Core");
>>> diff --git a/include/linux/leds.h b/include/linux/leds.h
>>> index f203a8f89d30..7f1428bb1e69 100644
>>> --- a/include/linux/leds.h
>>> +++ b/include/linux/leds.h
>>> @@ -50,6 +50,7 @@ struct led_classdev {
>>> #define LED_SYSFS_DISABLE (1 << 22)
>>> #define LED_DEV_CAP_FLASH (1 << 23)
>>> #define LED_HW_PLUGGABLE (1 << 24)
>>> +#define LED_BLINK_AT_PANIC (1 << 25)
>>>
>>> /* Set LED brightness level
>>> * Must not sleep. Use brightness_set_blocking for drivers
>>
>
--
Best regards,
Jacek Anaszewski
next prev parent reply other threads:[~2016-04-25 6:56 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-04-04 20:22 [PATCH 0/5] Extend the LED panic trigger Ezequiel Garcia
2016-04-04 20:22 ` [PATCH 1/5] leds: triggers: Allow to switch the trigger to "panic" on a kernel panic Ezequiel Garcia
2016-04-05 21:36 ` Jacek Anaszewski
2016-04-24 9:25 ` Pavel Machek
2016-04-24 9:29 ` Pavel Machek
2016-04-25 6:56 ` Jacek Anaszewski [this message]
2016-04-25 16:27 ` Ezequiel Garcia
2016-04-26 7:15 ` Jacek Anaszewski
2016-04-27 20:10 ` Ezequiel Garcia
2016-05-02 7:06 ` Pavel Machek
2016-04-04 20:22 ` [PATCH 2/5] leds: triggers: Add a led_trigger_event_nosleep API Ezequiel Garcia
2016-04-05 21:36 ` Jacek Anaszewski
2016-04-06 4:38 ` Ezequiel Garcia
2016-04-06 6:12 ` Jacek Anaszewski
2016-04-04 20:22 ` [PATCH 3/5] leds: trigger: panic: Use led_trigger_event_nosleep Ezequiel Garcia
2016-04-04 20:22 ` [PATCH 4/5] devicetree: leds: Introduce "panic-blink" optional property Ezequiel Garcia
2016-04-05 21:37 ` Jacek Anaszewski
2016-04-06 4:39 ` Ezequiel Garcia
2016-04-06 15:12 ` Rob Herring
2016-04-06 16:13 ` Ezequiel Garcia
2016-04-04 20:22 ` [PATCH 5/5] leds: gpio: Support the panic-blink firmware property Ezequiel Garcia
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