[PATCH RESEND v2] leds: fix hibernation on arm when gpio-led used with CPU led trigger

[grygorii.strashko at linaro.org]

From: Grygorii Strashko <Grygorii.Strashko at linaro.org>

Setting a dev_pm_ops suspend/resume pair of callbacks but not a set of
hibernation callbacks means those pm functions will not be
called upon hibernation - that leads to system crash on ARM during
freezing if gpio-led is used in combination with CPU led trigger.
It may happen after freeze_noirq stage (GPIO is suspended)
and before syscore_suspend stage (CPU led trigger is suspended)
- usually when disable_nonboot_cpus() is called.

Log:
  PM: noirq freeze of devices complete after 1.425 msecs
  Disabling non-boot CPUs ...
    ^ system may crash or stuck here with message (TI AM572x)

  WARNING: CPU: 0 PID: 3100 at drivers/bus/omap_l3_noc.c:148 l3_interrupt_handler+0x22c/0x370()
  44000000.ocp:L3 Custom Error: MASTER MPU TARGET L4_PER1_P3 (Idle): Data Access in Supervisor mode during Functional access

  CPU1: shutdown
    ^ or here

Fix this by using SIMPLE_DEV_PM_OPS, which appropriately
assigns the suspend and hibernation callbacks and move
led_suspend/led_resume under CONFIG_PM_SLEEP to avoid
build warnings.

Fixes: 73e1ab41a80d (leds: Convert led class driver from legacy pm ops to dev_pm_ops)
Signed-off-by: Grygorii Strashko <Grygorii.Strashko at linaro.org>
---

Hi All,

Could you pls pay attention on this patch?

This trivial patch was posted at Feb 2015 and
it's missed two merge windows already ((.

Rebased on top of next (4.1).

Changes in v2:
- fixed compile time warnings when !CONFIG_PM_SLEEP
- updated commit message

v2:
  https://lkml.org/lkml/2015/2/5/323
v1:
  https://lkml.org/lkml/2015/2/2/476

 drivers/leds/led-class.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/drivers/leds/led-class.c b/drivers/leds/led-class.c
index 728681d..7fb2a19 100644
--- a/drivers/leds/led-class.c
+++ b/drivers/leds/led-class.c
@@ -187,6 +187,7 @@ void led_classdev_resume(struct led_classdev *led_cdev)
 }
 EXPORT_SYMBOL_GPL(led_classdev_resume);
 
+#ifdef CONFIG_PM_SLEEP
 static int led_suspend(struct device *dev)
 {
 	struct led_classdev *led_cdev = dev_get_drvdata(dev);
@@ -206,11 +207,9 @@ static int led_resume(struct device *dev)
 
 	return 0;
 }
+#endif
 
-static const struct dev_pm_ops leds_class_dev_pm_ops = {
-	.suspend        = led_suspend,
-	.resume         = led_resume,
-};
+static SIMPLE_DEV_PM_OPS(leds_class_dev_pm_ops, led_suspend, led_resume);
 
 static int match_name(struct device *dev, const void *data)
 {
-- 
1.9.1