diff options
Diffstat (limited to 'drivers/gpio/gpiolib.c')
| -rw-r--r-- | drivers/gpio/gpiolib.c | 21 |
1 files changed, 19 insertions, 2 deletions
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c index 754836e4ca0e..1eebd69f369e 100644 --- a/drivers/gpio/gpiolib.c +++ b/drivers/gpio/gpiolib.c @@ -600,6 +600,9 @@ out_free_lh: * @events: KFIFO for the GPIO events * @read_lock: mutex lock to protect reads from colliding with adding * new events to the FIFO + * @timestamp: cache for the timestamp storing it between hardirq + * and IRQ thread, used to bring the timestamp close to the actual + * event */ struct lineevent_state { struct gpio_device *gdev; @@ -610,6 +613,7 @@ struct lineevent_state { wait_queue_head_t wait; DECLARE_KFIFO(events, struct gpioevent_data, 16); struct mutex read_lock; + u64 timestamp; }; #define GPIOEVENT_REQUEST_VALID_FLAGS \ @@ -747,7 +751,7 @@ static irqreturn_t lineevent_irq_thread(int irq, void *p) /* Do not leak kernel stack to userspace */ memset(&ge, 0, sizeof(ge)); - ge.timestamp = ktime_get_real_ns(); + ge.timestamp = le->timestamp; level = gpiod_get_value_cansleep(le->desc); if (le->eflags & GPIOEVENT_REQUEST_RISING_EDGE @@ -775,6 +779,19 @@ static irqreturn_t lineevent_irq_thread(int irq, void *p) return IRQ_HANDLED; } +static irqreturn_t lineevent_irq_handler(int irq, void *p) +{ + struct lineevent_state *le = p; + + /* + * Just store the timestamp in hardirq context so we get it as + * close in time as possible to the actual event. + */ + le->timestamp = ktime_get_real_ns(); + + return IRQ_WAKE_THREAD; +} + static int lineevent_create(struct gpio_device *gdev, void __user *ip) { struct gpioevent_request eventreq; @@ -867,7 +884,7 @@ static int lineevent_create(struct gpio_device *gdev, void __user *ip) /* Request a thread to read the events */ ret = request_threaded_irq(le->irq, - NULL, + lineevent_irq_handler, lineevent_irq_thread, irqflags, le->label, |