From: Andy Shevchenko <andy.shevchenko@gmail.com>
To: Kent Gibson <warthog618@gmail.com>
Cc: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
"open list:GPIO SUBSYSTEM" <linux-gpio@vger.kernel.org>,
Bartosz Golaszewski <bgolaszewski@baylibre.com>,
Linus Walleij <linus.walleij@linaro.org>,
Arnd Bergmann <arnd@arndb.de>
Subject: Re: [PATCH v9 09/20] gpiolib: cdev: support edge detection for uAPI v2
Date: Fri, 25 Sep 2020 12:35:49 +0300 [thread overview]
Message-ID: <CAHp75Vd7Bmy5FWSputDCAAwSheH6ugszMyCcu1HOgC7BPVEX-w@mail.gmail.com> (raw)
In-Reply-To: <20200924030732.GB11575@sol>
On Thu, Sep 24, 2020 at 6:07 AM Kent Gibson <warthog618@gmail.com> wrote:
> On Wed, Sep 23, 2020 at 06:47:28PM +0300, Andy Shevchenko wrote:
> > On Tue, Sep 22, 2020 at 5:35 AM Kent Gibson <warthog618@gmail.com> wrote:
...
> Also, this code is drawn from lineevent_irq_thread(), which is ordered
> this way.
Negative conditionals are slightly harder to read.
...
> > > + if (!line->timestamp_ns) {
> > > + le.timestamp_ns = ktime_get_ns();
> > > + if (lr->num_lines != 1)
> > > + line->req_seqno = atomic_inc_return(&lr->seqno);
> > > + } else {
> > > + le.timestamp_ns = line->timestamp_ns;
> > > > + }
> >
> > Ditto.
>
> Firstly, drawn from lineevent_irq_thread() which is structured this way.
>
> In this case the comment relates to the condition being true, so
> re-ordering the if/else would be confusing - unless the comment were
> moved into the corresponding body??
Yes.
...
> > > + irq = gpiod_to_irq(line->desc);
> > > + if (irq <= 0)
> > > + return -ENODEV;
> >
> > So, you mean this is part of ABI. Can we return more appropriate code,
> > because getting no IRQ doesn't mean we don't have a device.
> > Also does 0 case have the same meaning?
>
> Firstly, this code is drawn from lineevent_create(), so any changes
> here should be considered for there as well - though this may
> constitute an ABI change??
For v1 probably, for v2 we are free to fix this.
> I agree ENODEV doesn't seem right here. Are you ok with ENXIO?
Yes.
> From gpiod_to_irq():
>
> /* Zero means NO_IRQ */
> if (!retirq)
> return -ENXIO;
>
> so it can't even return a 0 :-| - we're just being cautious.
I would drop = part then.
--
With Best Regards,
Andy Shevchenko
next prev parent reply other threads:[~2020-09-25 9:36 UTC|newest]
Thread overview: 73+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-22 2:31 [PATCH v9 00/20] gpio: cdev: add uAPI v2 Kent Gibson
2020-09-22 2:31 ` [PATCH v9 01/20] gpiolib: cdev: gpio_desc_to_lineinfo() should set info offset Kent Gibson
2020-09-22 2:31 ` [PATCH v9 02/20] gpiolib: cdev: replace strncpy() with strscpy() Kent Gibson
2020-09-22 2:31 ` [PATCH v9 03/20] gpio: uapi: define GPIO_MAX_NAME_SIZE for array sizes Kent Gibson
2020-09-22 2:31 ` [PATCH v9 04/20] gpio: uapi: define uAPI v2 Kent Gibson
2020-09-22 7:41 ` Arnd Bergmann
2020-09-22 9:50 ` Bartosz Golaszewski
2020-09-22 10:07 ` Kent Gibson
2020-09-23 10:04 ` Andy Shevchenko
2020-09-23 10:30 ` Kent Gibson
2020-09-23 11:16 ` Andy Shevchenko
2020-09-23 12:18 ` Arnd Bergmann
2020-09-23 15:15 ` Andy Shevchenko
2020-09-22 2:31 ` [PATCH v9 05/20] gpiolib: make cdev a build option Kent Gibson
2020-09-22 2:31 ` [PATCH v9 06/20] gpiolib: add build option for CDEV v1 ABI Kent Gibson
2020-09-22 2:31 ` [PATCH v9 07/20] gpiolib: cdev: support GPIO_V2_GET_LINE_IOCTL and GPIO_V2_LINE_GET_VALUES_IOCTL Kent Gibson
2020-09-23 11:11 ` Andy Shevchenko
2020-09-24 8:09 ` Kent Gibson
2020-09-25 10:06 ` Andy Shevchenko
2020-09-26 9:16 ` Kent Gibson
2020-09-27 9:00 ` Andy Shevchenko
2020-09-27 12:39 ` Kent Gibson
2020-09-24 14:29 ` Bartosz Golaszewski
2020-09-22 2:31 ` [PATCH v9 08/20] gpiolib: cdev: support GPIO_V2_GET_LINEINFO_IOCTL and GPIO_V2_GET_LINEINFO_WATCH_IOCTL Kent Gibson
2020-09-23 15:41 ` Andy Shevchenko
2020-09-24 2:39 ` Kent Gibson
2020-09-24 8:39 ` Andy Shevchenko
2020-09-24 9:48 ` Kent Gibson
2020-09-25 10:12 ` Andy Shevchenko
2020-09-25 11:56 ` Kent Gibson
2020-09-25 14:43 ` Andy Shevchenko
2020-09-25 5:32 ` Kent Gibson
2020-09-22 2:31 ` [PATCH v9 09/20] gpiolib: cdev: support edge detection for uAPI v2 Kent Gibson
2020-09-23 15:47 ` Andy Shevchenko
2020-09-24 3:07 ` Kent Gibson
2020-09-25 9:35 ` Andy Shevchenko [this message]
2020-09-25 12:26 ` Kent Gibson
2020-09-25 14:48 ` Andy Shevchenko
2020-09-22 2:31 ` [PATCH v9 10/20] gpiolib: cdev: support GPIO_V2_LINE_SET_CONFIG_IOCTL Kent Gibson
2020-09-23 16:14 ` Andy Shevchenko
2020-09-23 16:15 ` Andy Shevchenko
2020-09-24 3:24 ` Kent Gibson
2020-09-24 8:26 ` Andy Shevchenko
2020-09-24 9:26 ` Kent Gibson
2020-09-25 9:49 ` Andy Shevchenko
2020-09-22 2:31 ` [PATCH v9 11/20] gpiolib: cdev: support GPIO_V2_LINE_SET_VALUES_IOCTL Kent Gibson
2020-09-23 16:18 ` Andy Shevchenko
2020-09-24 7:32 ` Kent Gibson
2020-09-24 8:21 ` Andy Shevchenko
2020-09-24 9:08 ` Kent Gibson
2020-09-24 12:46 ` Kent Gibson
2020-09-25 9:57 ` Andy Shevchenko
2020-09-25 12:16 ` Kent Gibson
2020-09-22 2:31 ` [PATCH v9 12/20] gpiolib: cdev: support setting debounce Kent Gibson
2020-09-23 16:27 ` Andy Shevchenko
2020-09-24 7:48 ` Kent Gibson
2020-09-25 9:43 ` Andy Shevchenko
2020-09-22 2:31 ` [PATCH v9 13/20] gpio: uapi: document uAPI v1 as deprecated Kent Gibson
2020-09-22 7:49 ` Arnd Bergmann
2020-09-22 8:11 ` Andy Shevchenko
2020-09-22 9:05 ` Kent Gibson
2020-09-22 2:31 ` [PATCH v9 14/20] tools: gpio: port lsgpio to v2 uAPI Kent Gibson
2020-09-22 2:31 ` [PATCH v9 15/20] tools: gpio: port gpio-watch " Kent Gibson
2020-09-22 2:31 ` [PATCH v9 16/20] tools: gpio: rename nlines to num_lines Kent Gibson
2020-09-22 2:31 ` [PATCH v9 17/20] tools: gpio: port gpio-hammer to v2 uAPI Kent Gibson
2020-09-23 16:30 ` Andy Shevchenko
2020-09-24 7:50 ` Kent Gibson
2020-09-22 2:31 ` [PATCH v9 18/20] tools: gpio: port gpio-event-mon " Kent Gibson
2020-09-22 2:31 ` [PATCH v9 19/20] tools: gpio: add multi-line monitoring to gpio-event-mon Kent Gibson
2020-09-22 2:31 ` [PATCH v9 20/20] tools: gpio: add debounce support " Kent Gibson
2020-09-23 16:35 ` [PATCH v9 00/20] gpio: cdev: add uAPI v2 Andy Shevchenko
2020-09-24 8:00 ` Kent Gibson
2020-09-25 9:44 ` Andy Shevchenko
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