* [PATCH v2] leds: core: use deferred probing if default trigger isn't available yet
@ 2017-02-24 6:41 Heiner Kallweit
2017-02-26 17:11 ` Jacek Anaszewski
2017-02-27 11:12 ` Pavel Machek
0 siblings, 2 replies; 4+ messages in thread
From: Heiner Kallweit @ 2017-02-24 6:41 UTC (permalink / raw)
To: Jacek Anaszewski, Richard Purdie, Pavel Machek; +Cc: linux-leds@vger.kernel.org
When registering a LED device we have the option to set a default trigger.
Depending on load order of drivers this trigger may not be available yet.
(affected LED device in my case: a DT-configured GPIO LED)
So far if the default trigger can't be found this error is silently
ignored.
Let's change this to return EPROBE_DEFER if the default trigger can't be
found. This gives the system the chance to probe the LED device later
once the trigger is available.
In addition in led_trigger_set_default break out of the loop when trigger
has been found.
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
---
v2:
- in led_trigger_set_default break out of loop when trigger has been found
---
drivers/leds/led-class.c | 6 +++++-
drivers/leds/led-triggers.c | 12 +++++++++---
include/linux/leds.h | 5 +++--
3 files changed, 17 insertions(+), 6 deletions(-)
diff --git a/drivers/leds/led-class.c b/drivers/leds/led-class.c
index f2b0a80a..efe4f5a3 100644
--- a/drivers/leds/led-class.c
+++ b/drivers/leds/led-class.c
@@ -295,7 +295,11 @@ int led_classdev_register(struct device *parent, struct led_classdev *led_cdev)
led_init_core(led_cdev);
#ifdef CONFIG_LEDS_TRIGGERS
- led_trigger_set_default(led_cdev);
+ ret = led_trigger_set_default(led_cdev);
+ if (ret) {
+ led_classdev_unregister(led_cdev);
+ return ret;
+ }
#endif
dev_dbg(parent, "Registered led device: %s\n",
diff --git a/drivers/leds/led-triggers.c b/drivers/leds/led-triggers.c
index 431123b0..572ede29 100644
--- a/drivers/leds/led-triggers.c
+++ b/drivers/leds/led-triggers.c
@@ -157,21 +157,27 @@ void led_trigger_remove(struct led_classdev *led_cdev)
}
EXPORT_SYMBOL_GPL(led_trigger_remove);
-void led_trigger_set_default(struct led_classdev *led_cdev)
+int led_trigger_set_default(struct led_classdev *led_cdev)
{
struct led_trigger *trig;
+ int ret = -EPROBE_DEFER;
if (!led_cdev->default_trigger)
- return;
+ return 0;
down_read(&triggers_list_lock);
down_write(&led_cdev->trigger_lock);
list_for_each_entry(trig, &trigger_list, next_trig) {
- if (!strcmp(led_cdev->default_trigger, trig->name))
+ if (!strcmp(led_cdev->default_trigger, trig->name)) {
led_trigger_set(led_cdev, trig);
+ ret = 0;
+ break;
+ }
}
up_write(&led_cdev->trigger_lock);
up_read(&triggers_list_lock);
+
+ return ret;
}
EXPORT_SYMBOL_GPL(led_trigger_set_default);
diff --git a/include/linux/leds.h b/include/linux/leds.h
index 38c0bd7c..3e36ce31 100644
--- a/include/linux/leds.h
+++ b/include/linux/leds.h
@@ -280,7 +280,7 @@ extern void led_trigger_blink_oneshot(struct led_trigger *trigger,
unsigned long *delay_on,
unsigned long *delay_off,
int invert);
-extern void led_trigger_set_default(struct led_classdev *led_cdev);
+extern int led_trigger_set_default(struct led_classdev *led_cdev);
extern void led_trigger_set(struct led_classdev *led_cdev,
struct led_trigger *trigger);
extern void led_trigger_remove(struct led_classdev *led_cdev);
@@ -326,7 +326,8 @@ static inline void led_trigger_blink_oneshot(struct led_trigger *trigger,
unsigned long *delay_on,
unsigned long *delay_off,
int invert) {}
-static inline void led_trigger_set_default(struct led_classdev *led_cdev) {}
+static inline int led_trigger_set_default(struct led_classdev *led_cdev)
+ { return 0; }
static inline void led_trigger_set(struct led_classdev *led_cdev,
struct led_trigger *trigger) {}
static inline void led_trigger_remove(struct led_classdev *led_cdev) {}
--
2.11.1
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH v2] leds: core: use deferred probing if default trigger isn't available yet
2017-02-24 6:41 [PATCH v2] leds: core: use deferred probing if default trigger isn't available yet Heiner Kallweit
@ 2017-02-26 17:11 ` Jacek Anaszewski
2017-02-27 11:12 ` Pavel Machek
1 sibling, 0 replies; 4+ messages in thread
From: Jacek Anaszewski @ 2017-02-26 17:11 UTC (permalink / raw)
To: Heiner Kallweit, Richard Purdie, Pavel Machek; +Cc: linux-leds@vger.kernel.org
Hi Heiner,
Thanks for the updated patch.
On 02/24/2017 07:41 AM, Heiner Kallweit wrote:
> When registering a LED device we have the option to set a default trigger.
> Depending on load order of drivers this trigger may not be available yet.
> (affected LED device in my case: a DT-configured GPIO LED)
> So far if the default trigger can't be found this error is silently
> ignored.
>
> Let's change this to return EPROBE_DEFER if the default trigger can't be
> found. This gives the system the chance to probe the LED device later
> once the trigger is available.
>
> In addition in led_trigger_set_default break out of the loop when trigger
> has been found.
>
> Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
> ---
> v2:
> - in led_trigger_set_default break out of loop when trigger has been found
> ---
> drivers/leds/led-class.c | 6 +++++-
> drivers/leds/led-triggers.c | 12 +++++++++---
> include/linux/leds.h | 5 +++--
> 3 files changed, 17 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/leds/led-class.c b/drivers/leds/led-class.c
> index f2b0a80a..efe4f5a3 100644
> --- a/drivers/leds/led-class.c
> +++ b/drivers/leds/led-class.c
> @@ -295,7 +295,11 @@ int led_classdev_register(struct device *parent, struct led_classdev *led_cdev)
> led_init_core(led_cdev);
>
> #ifdef CONFIG_LEDS_TRIGGERS
> - led_trigger_set_default(led_cdev);
> + ret = led_trigger_set_default(led_cdev);
> + if (ret) {
> + led_classdev_unregister(led_cdev);
> + return ret;
> + }
> #endif
>
> dev_dbg(parent, "Registered led device: %s\n",
> diff --git a/drivers/leds/led-triggers.c b/drivers/leds/led-triggers.c
> index 431123b0..572ede29 100644
> --- a/drivers/leds/led-triggers.c
> +++ b/drivers/leds/led-triggers.c
> @@ -157,21 +157,27 @@ void led_trigger_remove(struct led_classdev *led_cdev)
> }
> EXPORT_SYMBOL_GPL(led_trigger_remove);
>
> -void led_trigger_set_default(struct led_classdev *led_cdev)
> +int led_trigger_set_default(struct led_classdev *led_cdev)
> {
> struct led_trigger *trig;
> + int ret = -EPROBE_DEFER;
>
> if (!led_cdev->default_trigger)
> - return;
> + return 0;
>
> down_read(&triggers_list_lock);
> down_write(&led_cdev->trigger_lock);
> list_for_each_entry(trig, &trigger_list, next_trig) {
> - if (!strcmp(led_cdev->default_trigger, trig->name))
> + if (!strcmp(led_cdev->default_trigger, trig->name)) {
> led_trigger_set(led_cdev, trig);
> + ret = 0;
> + break;
> + }
> }
> up_write(&led_cdev->trigger_lock);
> up_read(&triggers_list_lock);
> +
> + return ret;
> }
> EXPORT_SYMBOL_GPL(led_trigger_set_default);
>
> diff --git a/include/linux/leds.h b/include/linux/leds.h
> index 38c0bd7c..3e36ce31 100644
> --- a/include/linux/leds.h
> +++ b/include/linux/leds.h
> @@ -280,7 +280,7 @@ extern void led_trigger_blink_oneshot(struct led_trigger *trigger,
> unsigned long *delay_on,
> unsigned long *delay_off,
> int invert);
> -extern void led_trigger_set_default(struct led_classdev *led_cdev);
> +extern int led_trigger_set_default(struct led_classdev *led_cdev);
> extern void led_trigger_set(struct led_classdev *led_cdev,
> struct led_trigger *trigger);
> extern void led_trigger_remove(struct led_classdev *led_cdev);
> @@ -326,7 +326,8 @@ static inline void led_trigger_blink_oneshot(struct led_trigger *trigger,
> unsigned long *delay_on,
> unsigned long *delay_off,
> int invert) {}
> -static inline void led_trigger_set_default(struct led_classdev *led_cdev) {}
> +static inline int led_trigger_set_default(struct led_classdev *led_cdev)
> + { return 0; }
> static inline void led_trigger_set(struct led_classdev *led_cdev,
> struct led_trigger *trigger) {}
> static inline void led_trigger_remove(struct led_classdev *led_cdev) {}
>
Applied to the for-4.12 branch of linux-leds.git.
--
Best regards,
Jacek Anaszewski
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH v2] leds: core: use deferred probing if default trigger isn't available yet
2017-02-24 6:41 [PATCH v2] leds: core: use deferred probing if default trigger isn't available yet Heiner Kallweit
2017-02-26 17:11 ` Jacek Anaszewski
@ 2017-02-27 11:12 ` Pavel Machek
2017-02-27 19:55 ` Jacek Anaszewski
1 sibling, 1 reply; 4+ messages in thread
From: Pavel Machek @ 2017-02-27 11:12 UTC (permalink / raw)
To: Heiner Kallweit
Cc: Jacek Anaszewski, Richard Purdie, linux-leds@vger.kernel.org
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On Fri 2017-02-24 07:41:48, Heiner Kallweit wrote:
> When registering a LED device we have the option to set a default trigger.
> Depending on load order of drivers this trigger may not be available yet.
> (affected LED device in my case: a DT-configured GPIO LED)
> So far if the default trigger can't be found this error is silently
> ignored.
>
> Let's change this to return EPROBE_DEFER if the default trigger can't be
> found. This gives the system the chance to probe the LED device later
> once the trigger is available.
>
> In addition in led_trigger_set_default break out of the loop when trigger
> has been found.
Hmm. Problem with this is that if the we configure non-existing
trigger, or trigger not configured in current kernel, LED will
disappear and user will have "fun" debugging why, right?
Pavel
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH v2] leds: core: use deferred probing if default trigger isn't available yet
2017-02-27 11:12 ` Pavel Machek
@ 2017-02-27 19:55 ` Jacek Anaszewski
0 siblings, 0 replies; 4+ messages in thread
From: Jacek Anaszewski @ 2017-02-27 19:55 UTC (permalink / raw)
To: Pavel Machek, Heiner Kallweit; +Cc: Richard Purdie, linux-leds@vger.kernel.org
On 02/27/2017 12:12 PM, Pavel Machek wrote:
> On Fri 2017-02-24 07:41:48, Heiner Kallweit wrote:
>> When registering a LED device we have the option to set a default trigger.
>> Depending on load order of drivers this trigger may not be available yet.
>> (affected LED device in my case: a DT-configured GPIO LED)
>> So far if the default trigger can't be found this error is silently
>> ignored.
>>
>> Let's change this to return EPROBE_DEFER if the default trigger can't be
>> found. This gives the system the chance to probe the LED device later
>> once the trigger is available.
>>
>> In addition in led_trigger_set_default break out of the loop when trigger
>> has been found.
>
> Hmm. Problem with this is that if the we configure non-existing
> trigger, or trigger not configured in current kernel, LED will
> disappear and user will have "fun" debugging why, right?
Right, so I propose to add suitable dev_err logging in
led_classdev_register() if led_trigger_set_default() returns
non-zero.
--
Best regards,
Jacek Anaszewski
^ permalink raw reply [flat|nested] 4+ messages in thread
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2017-02-24 6:41 [PATCH v2] leds: core: use deferred probing if default trigger isn't available yet Heiner Kallweit
2017-02-26 17:11 ` Jacek Anaszewski
2017-02-27 11:12 ` Pavel Machek
2017-02-27 19:55 ` Jacek Anaszewski
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