Re: [PATCH] gpio: Timestamp events in hardirq handler

[Alexander Stein <alexander.stein@systec-electronic.com>]

On Thursday, November 30, 2017, 10:26:55 AM CET Linus Walleij wrote:
> --- a/drivers/gpio/gpiolib.c
> +++ b/drivers/gpio/gpiolib.c
> @@ -587,6 +587,9 @@ static int linehandle_create(struct gpio_device *gdev, void __user *ip)
>   * @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;
> @@ -597,6 +600,7 @@ struct lineevent_state {
>  	wait_queue_head_t wait;
>  	DECLARE_KFIFO(events, struct gpioevent_data, 16);
>  	struct mutex read_lock;
> +	s64 timestamp;
    ^^^
u64? ktime_get_real_ns() returns u64 and struct gpioevent_data
has __u64 for timestamp.

Best regards,
Alexander