From: Kent Gibson <warthog618@gmail.com>
To: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Cc: LKML <linux-kernel@vger.kernel.org>,
linux-gpio <linux-gpio@vger.kernel.org>,
Linus Walleij <linus.walleij@linaro.org>
Subject: Re: [PATCH v6 09/20] gpiolib: cdev: support edge detection for uAPI v2
Date: Thu, 3 Sep 2020 16:09:09 +0800 [thread overview]
Message-ID: <20200903080909.GA17108@sol> (raw)
In-Reply-To: <CAMpxmJW9EC_ocs8dA3j+QPu8sW4Na9WEvPYEUZjfxk4-ojf+kA@mail.gmail.com>
On Thu, Sep 03, 2020 at 09:55:22AM +0200, Bartosz Golaszewski wrote:
> On Mon, Aug 31, 2020 at 5:22 AM Kent Gibson <warthog618@gmail.com> wrote:
> >
> > Add support for edge detection to lines requested using
> > GPIO_V2_GET_LINE_IOCTL.
> >
> > The edge_detector implementation is based on the v1 lineevent
> > implementation.
> >
[snip]
> > + * close in time as possible to the actual event.
> > + */
> > + line->timestamp = ktime_get_ns();
> > +
> > + if (lr->num_lines != 1)
> > + line->req_seqno = atomic_inc_return(&lr->seqno);
>
> Do we never increase req_seqno for a single line?
>
For a single line we just use line_seqno for both to avoid the
atomic_inc here and so reduce the time spent in the ISR and any
SMP sync overheads.
As per the comment in struct linereq:
* @seqno: the sequence number for edge events generated on all lines in
* this line request. Note that this is not used when @num_lines is 1, as
* the line_seqno is then the same and is cheaper to calculate.
Cheers,
Kent.
next prev parent reply other threads:[~2020-09-03 8:09 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-31 3:19 [PATCH v6 00/20] gpio: cdev: add uAPI v2 Kent Gibson
2020-08-31 3:19 ` [PATCH v6 01/20] gpiolib: cdev: desc_to_lineinfo should set info offset Kent Gibson
2020-08-31 3:19 ` [PATCH v6 02/20] gpiolib: cdev: replace strncpy with strscpy Kent Gibson
2020-08-31 3:19 ` [PATCH v6 03/20] gpio: uapi: define GPIO_MAX_NAME_SIZE for array sizes Kent Gibson
2020-08-31 3:19 ` [PATCH v6 04/20] gpio: uapi: define uAPI v2 Kent Gibson
2020-09-04 6:23 ` Bartosz Golaszewski
2020-08-31 3:19 ` [PATCH v6 05/20] gpiolib: make cdev a build option Kent Gibson
2020-08-31 3:19 ` [PATCH v6 06/20] gpiolib: add build option for CDEV v1 ABI Kent Gibson
2020-08-31 3:19 ` [PATCH v6 07/20] gpiolib: cdev: support GPIO_V2_GET_LINE_IOCTL and GPIO_V2_LINE_GET_VALUES_IOCTL Kent Gibson
2020-09-03 7:42 ` Bartosz Golaszewski
2020-08-31 3:19 ` [PATCH v6 08/20] gpiolib: cdev: support GPIO_V2_GET_LINEINFO_IOCTL and GPIO_V2_GET_LINEINFO_WATCH_IOCTL Kent Gibson
2020-08-31 3:19 ` [PATCH v6 09/20] gpiolib: cdev: support edge detection for uAPI v2 Kent Gibson
2020-09-03 7:55 ` Bartosz Golaszewski
2020-09-03 8:09 ` Kent Gibson [this message]
2020-09-03 8:13 ` Bartosz Golaszewski
2020-08-31 3:19 ` [PATCH v6 10/20] gpiolib: cdev: support GPIO_V2_LINE_SET_CONFIG_IOCTL Kent Gibson
2020-08-31 3:19 ` [PATCH v6 11/20] gpiolib: cdev: support GPIO_V2_LINE_SET_VALUES_IOCTL Kent Gibson
2020-09-03 7:59 ` Bartosz Golaszewski
2020-09-03 9:31 ` Kent Gibson
2020-08-31 3:19 ` [PATCH v6 12/20] gpiolib: cdev: support setting debounce Kent Gibson
2020-08-31 3:19 ` [PATCH v6 13/20] gpio: uapi: document uAPI v1 as deprecated Kent Gibson
2020-08-31 3:20 ` [PATCH v6 14/20] tools: gpio: port lsgpio to v2 uAPI Kent Gibson
2020-08-31 3:20 ` [PATCH v6 15/20] tools: gpio: port gpio-watch " Kent Gibson
2020-08-31 3:20 ` [PATCH v6 16/20] tools: gpio: rename nlines to num_lines Kent Gibson
2020-08-31 3:20 ` [PATCH v6 17/20] tools: gpio: port gpio-hammer to v2 uAPI Kent Gibson
2020-08-31 3:20 ` [PATCH v6 18/20] tools: gpio: port gpio-event-mon " Kent Gibson
2020-08-31 3:20 ` [PATCH v6 19/20] tools: gpio: add multi-line monitoring to gpio-event-mon Kent Gibson
2020-08-31 3:20 ` [PATCH v6 20/20] tools: gpio: add debounce support " Kent Gibson
2020-09-03 8:02 ` [PATCH v6 00/20] gpio: cdev: add uAPI v2 Bartosz Golaszewski
2020-09-03 8:37 ` Kent Gibson
2020-09-04 12:52 ` Kent Gibson
2020-09-04 13:02 ` Bartosz Golaszewski
2020-09-08 15:24 ` Shuah Khan
2020-09-08 15:54 ` Bartosz Golaszewski
2020-09-08 16:04 ` Shuah Khan
2020-09-09 1:09 ` Kent Gibson
2020-09-09 1:15 ` Shuah Khan
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