[OpenWrt-Devel] [PATCH v2] ath79: use gpio_hog instead of gpio-export

[mail at adrianschmutzler.de]

Hi Piotr,

> -----Original Message-----
> From: openwrt-devel [mailto:openwrt-devel-bounces at lists.openwrt.org]
> On Behalf Of Piotr Dymacz
> Sent: Samstag, 16. November 2019 15:51
> To: Adrian Schmutzler <mail at adrianschmutzler.de>; openwrt-
> devel at lists.openwrt.org
> Cc: bjorn at mork.no; 'Enrico Mioso' <mrkiko.rs at gmail.com>; 'Mathias Kresin'
> <dev at kresin.me>; 'Birger Koblitz' <mail at birger-koblitz.de>
> Subject: Re: [OpenWrt-Devel] [PATCH v2] ath79: use gpio_hog instead of
> gpio-export
> 
> Hi Adrian,
> 
> Sorry for a late reply.
> 
> On 06.11.2019 16:47, Adrian Schmutzler wrote:
> > Hi,
> >
> >> Wouldn't it make more sense to spend time now on implementing
> >> future-proof solution and switch to it when it's ready?
> >
> > Obviously, yes. But for the meantime, I'd like to have a less-arbitrary status
> quo.
> 
> For me, in that case, I would leave decision to the author of support _and_
> reviewer/committer.
> 
> >> I believe the major issue here is that there is no 'in place'
> >> replacement for 'gpio-export' (or I'm just not aware of it).
> >>
> > [...]
> >>
> >> Are there any other reasons to get rid of 'gpio-export' _now_, other
> >> than the fact upstream rejected this approach?
> >>
> >   [...]
> >>
> >> '03_gpio_switches' doesn't handle inputs.
> >>
> >> Of course, it has advantages, like the fact it makes the GPIO setup
> >> uci-based but on the other hand... it does its job fairly late during
> >> bootup. In some cases, you might want to, for example, enable power
> >> for 3/4G modem as early as possible, to give it time to register in network.
> >>
> >> Anyway, under the hood, it's the same approach, export named GPIO
> >> using _deprecated_ sysfs. Excluding uci and place in boot time where
> >> it happens, the difference is where the GPIOs are defined, DTS vs.
> >> user-space scripts.
> >>
> >
> > So, both 03_gpio_switches and gpio-hogs provide less functionality
> > than gpio-exports with no striking benefit. From that point of view we
> > should actually allow gpio-exports in device support submissions
> > again, and actually discourage gpio_hogs for the status quo ... (and
> > it would be better to convert hogs to exports and not the other way
> > around ...)
> 
> Someone could say that 'gpio-hog' is the accepted solution in upstream and
> the 'gpio-export' is the rejected one so we need to get rid of it ASAP.
> 
> Personally, I don't see now any good reason to convert everything back to
> 'gpio-export'. I would be just more pragmatic when reviewing and accepting
> boards support - if the author thinks that it would be better (look at it from
> usability point of view) to have user-space control on a specific GPIO line, I
> wouldn't ask him to use 'gpio-hog'. For me, also the uci approach is fine if
> there is no need to setup GPIO before the whole boot process finishes.
> 
> Still, in some cases maybe 'fixed-regulator' would fit even better than
> discussed solution. IIRC, at least in case of the USB, there is still a way to have
> control on the VBUS if 'fixed-regulator' is used (unload the driver, power
> goes off, load it back, power goes on).
> 
> I just don't think it makes sense to look for a consensus now on something
> which for sure has to go away/change in, I hope close future.

okay, I accept that.

I've marked this particular patch with "Rejected" already a week ago I think, but since it is consensus that replacement of gpio-export by gpio-hog reduces functionality, I will also mark the other patches attempting this conversion as "Rejected".

Best

Adrian

> 
> --
> Cheers,
> Piotr
> 
> >
> > Best
> >
> > Adrian
> >
> >
> > _______________________________________________
> > openwrt-devel mailing list
> > openwrt-devel at lists.openwrt.org
> > https://lists.openwrt.org/mailman/listinfo/openwrt-devel
> >
> 
> 
> _______________________________________________
> openwrt-devel mailing list
> openwrt-devel at lists.openwrt.org
> https://lists.openwrt.org/mailman/listinfo/openwrt-devel
-------------- next part --------------
A non-text attachment was scrubbed...
Name: openpgp-digital-signature.asc
Type: application/pgp-signature
Size: 834 bytes
Desc: not available
URL: <http://lists.infradead.org/pipermail/openwrt-devel/attachments/20191117/2eef8e6b/attachment.sig>
-------------- next part --------------
_______________________________________________
openwrt-devel mailing list
openwrt-devel at lists.openwrt.org
https://lists.openwrt.org/mailman/listinfo/openwrt-devel