[PATCH] leds: leds-regulator.c, fix handling already enabled regulators

From: Antonio Ospite
Date: Wed Mar 23 2011 - 17:01:05 EST

Make the driver aware of the initial status of the regulator.

The leds-regulator driver was ignoring the initial status of the
regulator; this resulted in rdev->use_count incremented up to 2 after
calling regulator_led_set_value() in the .probe method when a regulator
was already enabled at insmod time, and this made impossible to ever
disable the regulator.

Signed-off-by: Antonio Ospite <ospite@xxxxxxxxxxxxxxxxx>

This problem was anticipated by Mark Brown on the very first submission
of the driver but my knowledge about regulators at the time made me
overlook what he was asking for, now that I have actually experienced
the problem I've finally figured out what Mark was really referring to.

NOTE: initially I thought about CC-ing stable@xxxxxxxxxx as well on
this, as it is an actual fix, but then I checked that there are
currently no users of the driver in mainline linux and I dropped it, is
that how it should be?

Antonio Ospite

drivers/leds/leds-regulator.c | 4 ++++
1 files changed, 4 insertions(+), 0 deletions(-)

diff --git a/drivers/leds/leds-regulator.c b/drivers/leds/leds-regulator.c
index 3790816..8497f56 100644
--- a/drivers/leds/leds-regulator.c
+++ b/drivers/leds/leds-regulator.c
@@ -178,6 +178,10 @@ static int __devinit regulator_led_probe(struct platform_device *pdev)
led->cdev.flags |= LED_CORE_SUSPENDRESUME;
led->vcc = vcc;

+ /* to handle correctly an already enabled regulator */
+ if (regulator_is_enabled(led->vcc))
+ led->enabled = 1;
INIT_WORK(&led->work, led_work);


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