From: Bartosz Golaszewski <brgl@bgdev.pl>
To: Kent Gibson <warthog618@gmail.com>
Cc: Bartosz Golaszewski <bgolaszewski@baylibre.com>,
linux-gpio <linux-gpio@vger.kernel.org>
Subject: Re: [libgpiod] [PATCH 11/19] API: add support for SET_CONFIG
Date: Wed, 20 Nov 2019 16:18:24 +0100 [thread overview]
Message-ID: <CAMRc=Mex6M9Mmke9ajgLcpy4-Th+GOhycjeEiM+5PMBvmA+Apw@mail.gmail.com> (raw)
In-Reply-To: <20191120143644.GA5865@sol>
śr., 20 lis 2019 o 15:36 Kent Gibson <warthog618@gmail.com> napisał(a):
>
> On Wed, Nov 20, 2019 at 03:18:36PM +0100, Bartosz Golaszewski wrote:
> > śr., 20 lis 2019 o 15:13 Kent Gibson <warthog618@gmail.com> napisał(a):
> > >
> > > On Wed, Nov 20, 2019 at 03:08:57PM +0100, Bartosz Golaszewski wrote:
> > > > śr., 20 lis 2019 o 14:59 Kent Gibson <warthog618@gmail.com> napisał(a):
> > > > >
> > > > > On Wed, Nov 20, 2019 at 12:00:45PM +0100, Bartosz Golaszewski wrote:
> > > > > > wt., 19 lis 2019 o 16:53 Kent Gibson <warthog618@gmail.com> napisał(a):
> > > > > > >
> > > > > > > On Mon, Nov 18, 2019 at 10:48:25PM +0800, Kent Gibson wrote:
> > > > > > > > On Mon, Nov 18, 2019 at 02:52:04PM +0100, Bartosz Golaszewski
> > > > > > > > > > +
> > > > > > > > > > +int gpiod_line_set_flags_bulk(struct gpiod_line_bulk *bulk, int flags)
> > > > > > > > > > +{
> > > > > > > > > > + struct gpiod_line *line;
> > > > > > > > > > + int values[GPIOD_LINE_BULK_MAX_LINES];
> > > > > > > > > > + unsigned int i;
> > > > > > > > > > + int direction;
> > > > > > > > > > +
> > > > > > > > > > + line = gpiod_line_bulk_get_line(bulk, 0);
> > > > > > > > > > + if (line->as_is) {
> > > > > > > > >
> > > > > > > > > Can you explain the purpose of this as_is field? I'm not sure this is
> > > > > > > > > really needed.
> > > > > > > > >
> > > > > > > >
> > > > > > > > It is there for gpiod_set_flags, which has to populate the direction
> > > > > > > > flags in the SET_CONFIG ioctl. The existing line->direction is
> > > > > > > > either input or output. It is drawn from GPIOLINE_FLAG_IS_OUT, so
> > > > > > > > as-is is gets mapped to input.
> > > > > > > > I didn't want to change the existing line->direction, and adding the
> > > > > > > > as-is seemed clearer than adding another flavour of direction that
> > > > > > > > contained all three.
> > > > > > > >
> > > > > > >
> > > > > > > Hmmm, I think I see what you were getting at - the line->direction is the
> > > > > > > direction from the kernel, so it doesn't hurt to use that value to set the
> > > > > > > corresponding request flags - even if the original request was as-is??
> > > > > > >
> > > > > > > If that is the case then the line->as_is can be dropped throughout.
> > > > > > >
> > > > > > > Kent.
> > > > > > >
> > > > > >
> > > > > > Yes, this is what I was thinking. Just need to make sure the value
> > > > > > from the kernel is up-to-date.
> > > > > >
> > > > >
> > > > > So fail if needs_update?
> > > > >
> > > > > Kent.
> > > >
> > > > I'd say: do an implicit update before setting config.
> > > >
> > >
> > > So gpiod_line_update if needs_update, and fail if that fails?
> > >
> > > Kent.
> >
> > Without the if - needs_update is only set if an implicit update fails
> > in line_maybe_update(). But in this case we need to be sure, so do it
> > unconditionally.
> >
>
> Given that line_maybe_update is called at the end of request creation, and
> whenever set_config is called, how can line->direction be inconsistent
> with the kernel state - as long as needs_update is false?
>
I don't think we should call line_maybe_update() on set_config() - in
this case we should call gpiod_line_update() and fail in set_config()
if it fails.
I hope that's clearer.
Bart
> Kent.
next prev parent reply other threads:[~2019-11-20 15:18 UTC|newest]
Thread overview: 58+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-15 14:43 [libgpiod] [PATCH 00/19] Add support for bias flags and SET_CONFIG Kent Gibson
2019-11-15 14:43 ` [libgpiod] [PATCH 01/19] core: move request flag to handle flag conversion into a separate function Kent Gibson
2019-11-15 14:43 ` [libgpiod] [PATCH 02/19] API: add support for bias flags Kent Gibson
2019-11-18 13:51 ` Bartosz Golaszewski
2019-11-18 14:12 ` Kent Gibson
2019-11-15 14:43 ` [libgpiod] [PATCH 03/19] core: fix misspelling of parameter Kent Gibson
2019-11-15 14:43 ` [libgpiod] [PATCH 04/19] tests: add tests for bias flags Kent Gibson
2019-11-18 13:51 ` Bartosz Golaszewski
2019-11-18 14:14 ` Kent Gibson
2019-11-15 14:43 ` [libgpiod] [PATCH 05/19] bindings: cxx: drop noexcept from direction and active_state Kent Gibson
2019-11-15 14:43 ` [libgpiod] [PATCH 06/19] bindings: cxx: initialise bitset with integer instead of string Kent Gibson
2019-11-18 13:51 ` Bartosz Golaszewski
2019-11-18 14:17 ` Kent Gibson
2019-11-15 14:43 ` [libgpiod] [PATCH 07/19] bindings: cxx: add support for bias flags Kent Gibson
2019-11-15 14:43 ` [libgpiod] [PATCH 08/19] bindings: cxx: tests: add tests " Kent Gibson
2019-11-15 14:43 ` [libgpiod] [PATCH 09/19] bindings: python: add support " Kent Gibson
2019-11-15 14:43 ` [libgpiod] [PATCH 10/19] bindings: python: tests: add tests " Kent Gibson
2019-11-15 14:43 ` [libgpiod] [PATCH 11/19] API: add support for SET_CONFIG Kent Gibson
2019-11-18 13:52 ` Bartosz Golaszewski
2019-11-18 14:48 ` Kent Gibson
2019-11-19 15:52 ` Kent Gibson
2019-11-20 11:00 ` Bartosz Golaszewski
2019-11-20 13:58 ` Kent Gibson
2019-11-20 14:08 ` Bartosz Golaszewski
2019-11-20 14:13 ` Kent Gibson
2019-11-20 14:18 ` Bartosz Golaszewski
2019-11-20 14:36 ` Kent Gibson
2019-11-20 15:18 ` Bartosz Golaszewski [this message]
2019-11-21 0:34 ` Kent Gibson
2019-11-21 7:13 ` Bartosz Golaszewski
2019-11-21 7:46 ` Kent Gibson
2019-11-21 8:46 ` Bartosz Golaszewski
2019-11-21 9:30 ` Kent Gibson
2019-11-21 10:03 ` Bartosz Golaszewski
2019-11-21 10:18 ` Kent Gibson
2019-11-21 10:27 ` Bartosz Golaszewski
2019-11-21 10:31 ` Bartosz Golaszewski
2019-11-21 11:07 ` Kent Gibson
2019-11-21 15:22 ` Bartosz Golaszewski
2019-11-21 10:59 ` Kent Gibson
2019-11-21 15:20 ` Bartosz Golaszewski
2019-11-15 14:43 ` [libgpiod] [PATCH 12/19] tests: add tests " Kent Gibson
2019-11-15 14:43 ` [libgpiod] [PATCH 13/19] core: allow gpiod_line_set_value_bulk to accept null values Kent Gibson
2019-11-15 14:43 ` [libgpiod] [PATCH 14/19] bindings: cxx: add support for SET_CONFIG Kent Gibson
2019-11-15 14:43 ` [libgpiod] [PATCH 15/19] bindings: cxx: tests: add tests for SET_CONFIG methods Kent Gibson
2019-11-15 14:43 ` [libgpiod] [PATCH 16/19] bindings: python: add support for SET_CONFIG Kent Gibson
2019-11-15 14:43 ` [libgpiod] [PATCH 17/19] bindings: python: tests: add tests for SET_CONFIG methods Kent Gibson
2019-11-15 14:43 ` [libgpiod] [PATCH 18/19] tools: add support for bias flags Kent Gibson
2019-11-16 15:40 ` Kent Gibson
2019-11-17 12:18 ` Bartosz Golaszewski
2019-11-17 12:28 ` Kent Gibson
2019-11-17 13:12 ` Kent Gibson
2019-11-15 14:43 ` [libgpiod] [PATCH 19/19] treewide: change "correspond with" to "correspond to" Kent Gibson
2019-11-18 13:52 ` Bartosz Golaszewski
2019-11-18 15:01 ` Kent Gibson
2019-11-18 13:50 ` [libgpiod] [PATCH 00/19] Add support for bias flags and SET_CONFIG Bartosz Golaszewski
2019-11-18 14:09 ` Kent Gibson
2019-11-18 14:55 ` Bartosz Golaszewski
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