gpiolib: skip unwanted events, don't convert them to opposite edge

commit df1e76f28ffe87d1b065eecab2d0fbb89e6bdee5 upstream.

The previous fix for filtering out of unwatched events was not entirely
correct. Instead of skipping the events we don't want, they are now
interpreted as events with opposing edge.

In order to fix it: always read the GPIO line value on interrupt and
only emit the event if it corresponds with the event type we requested.

Fixes: ad537b822577 ("gpiolib: fix filtering out unwanted events")
Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index f2bb5122d2c26744eb36870ea2601f8ff2438ea4..063d176baa24a887ee4c561c32449e1c425c0b82 100644 (file)
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -703,24 +703,23 @@ static irqreturn_t lineevent_irq_thread(int irq, void *p)
 {
        struct lineevent_state *le = p;
        struct gpioevent_data ge;
-       int ret;
+       int ret, level;
 
        ge.timestamp = ktime_get_real_ns();
+       level = gpiod_get_value_cansleep(le->desc);
 
        if (le->eflags & GPIOEVENT_REQUEST_RISING_EDGE
            && le->eflags & GPIOEVENT_REQUEST_FALLING_EDGE) {
-               int level = gpiod_get_value_cansleep(le->desc);
-
                if (level)
                        /* Emit low-to-high event */
                        ge.id = GPIOEVENT_EVENT_RISING_EDGE;
                else
                        /* Emit high-to-low event */
                        ge.id = GPIOEVENT_EVENT_FALLING_EDGE;
-       } else if (le->eflags & GPIOEVENT_REQUEST_RISING_EDGE) {
+       } else if (le->eflags & GPIOEVENT_REQUEST_RISING_EDGE && level) {
                /* Emit low-to-high event */
                ge.id = GPIOEVENT_EVENT_RISING_EDGE;
-       } else if (le->eflags & GPIOEVENT_REQUEST_FALLING_EDGE) {
+       } else if (le->eflags & GPIOEVENT_REQUEST_FALLING_EDGE && !level) {
                /* Emit high-to-low event */
                ge.id = GPIOEVENT_EVENT_FALLING_EDGE;
        } else {