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authorFrans Klaver <frans.klaver@xsens.com>2015-01-14 09:15:44 +0100
committerSebastian Reichel <sre@kernel.org>2015-01-20 13:58:30 +0100
commitc1ada2ff8045eacc11a3b894f2056aa5457b17b5 (patch)
treed1df53ba2ab5ba64db7d68e8c52ccb26c36eb740 /drivers
parent2f6ea8ad738e7a9be1a675a4404606723797cc16 (diff)
downloadlinux-c1ada2ff8045eacc11a3b894f2056aa5457b17b5.tar.bz2
power: reset: ltc2952: check trigger value before starting timer
In ltc2952_poweroff_handler it is theoretically possible that the timer fails to start on first pass (button press), but succeeds in starting on the second (button release). This will cause the button press to be misinterpreted, and will incorrectly shut down the system. Because a picture says more than a thousand words: Expected behavior: tmr: ++++++++++ btn: -----__________----- Faulty behavior: tmr: +++++ btn: -----__________----- Legend: + timer runs _ button pressed - button depressed To prevent this from happening, check the value of the gpio before starting the timer. If the button is active, we should start the timer, else we should stop it. The situation described can now still occur if the polarity of the input pin is set incorrectly, but that at least is predictable behavior and can be detected during the first tests. Signed-off-by: Frans Klaver <frans.klaver@xsens.com> Signed-off-by: Sebastian Reichel <sre@kernel.org>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/power/reset/ltc2952-poweroff.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/power/reset/ltc2952-poweroff.c b/drivers/power/reset/ltc2952-poweroff.c
index 240b294a0980..b99bc251f5b4 100644
--- a/drivers/power/reset/ltc2952-poweroff.c
+++ b/drivers/power/reset/ltc2952-poweroff.c
@@ -160,7 +160,7 @@ static irqreturn_t ltc2952_poweroff_handler(int irq, void *dev_id)
return IRQ_HANDLED;
}
- if (!hrtimer_active(&data->timer_trigger)) {
+ if (gpiod_get_value(data->gpio_trigger)) {
if (hrtimer_start(&data->timer_trigger, data->trigger_delay,
HRTIMER_MODE_REL))
dev_err(data->dev, "unable to start the wait timer\n");