From: Stephen Warren <swarren@wwwdotorg.org>
To: Linus Walleij <linus.walleij@linaro.org>
Cc: Grant Likely <grant.likely@secretlab.ca>,
Alexandre Courbot <acourbot@nvidia.com>,
Arnd Bergmann <arnd@arndb.de>,
linux-arch <linux-arch@vger.kernel.org>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Alexandre Courbot <gnurou@gmail.com>,
Mark Brown <broonie@opensource.wolfsonmicro.com>,
Mike Turquette <mturquette@linaro.org>
Subject: Re: [PATCH 6/9] gpiolib: use descriptors internally
Date: Mon, 11 Feb 2013 10:39:17 -0700 [thread overview]
Message-ID: <51192CC5.9060300@wwwdotorg.org> (raw)
In-Reply-To: <CACRpkdagLssOG3FW8Qr1zqFabGMgdupADwg1=c0eQ7e76_XM5A@mail.gmail.com>
On 02/11/2013 07:09 AM, Linus Walleij wrote:
> On Sat, Feb 9, 2013 at 10:17 AM, Grant Likely <grant.likely@secretlab.ca> wrote:
>
>> The ERR_PTR()/IS_ERR() is a horrible pattern for code
>> readability because it breaks the expectations that programmers have for
>> what is and is not a bad pointer. There are decades of history where the
>> test for a bad pointer is 'if (!ptr)'. Not only does ERR_PTR make make
>> that test not work, but the compiler won't tell you when you get it
>> wrong.
>>
>> There are places where ERR_PTR makes sense. Particularly when
>> communicating with userspace where error codes have very specific
>> meanings, but I don't want it in the GPIO subsystem.
>
> OK I disagree but you get to decide.
>
> However if you take this all the way to the descriptor API
> it will make the consumer (driver) API for GPIO descriptors deviate
> from what is today used for clocks, regulators and pins.
>
> With all the resulting confusion for users.
> I've seen worse subsystem deviations though.
Sorry I haven't looked at the specific APIs this discussion refers to,
but clients of the GPIO descriptor API are going to need to distinguish
"fail" from "deferred probe", so at least some initial get-like API will
need to pass back some error detail...
next prev parent reply other threads:[~2013-02-11 17:39 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-02-02 16:29 [PATCH 0/9] gpiolib: remove gpio_desc[] static array Alexandre Courbot
2013-02-02 16:29 ` Alexandre Courbot
2013-02-02 16:29 ` [PATCH 1/9] gpiolib: link all gpio_chips using a list Alexandre Courbot
2013-02-05 17:00 ` Linus Walleij
2013-02-09 9:20 ` Grant Likely
2013-02-02 16:29 ` [PATCH 2/9] gpiolib: use gpio_chips list in gpiolib_sysfs_init Alexandre Courbot
2013-02-05 17:04 ` Linus Walleij
2013-02-09 9:22 ` Grant Likely
2013-02-02 16:29 ` [PATCH 3/9] gpiolib: use gpio_chips list in gpiochip_find Alexandre Courbot
2013-02-05 17:05 ` Linus Walleij
2013-02-09 9:25 ` Grant Likely
2013-02-02 16:29 ` [PATCH 4/9] gpiolib: use gpio_chips list in sysfs ops Alexandre Courbot
2013-02-05 17:15 ` Linus Walleij
2013-02-09 9:37 ` Grant Likely
2013-02-09 13:53 ` Alexandre Courbot
2013-02-02 16:29 ` [PATCH 5/9] gpiolib: use gpio_chips list in gpiochip_find_base Alexandre Courbot
2013-02-05 17:21 ` Linus Walleij
2013-02-06 4:48 ` Alex Courbot
2013-02-09 9:47 ` Grant Likely
2013-02-02 16:29 ` [PATCH 6/9] gpiolib: use descriptors internally Alexandre Courbot
2013-02-05 17:53 ` Linus Walleij
2013-02-07 6:57 ` Alexandre Courbot
2013-02-09 9:17 ` Grant Likely
2013-02-11 14:09 ` Linus Walleij
2013-02-11 15:40 ` Paul Mundt
2013-02-11 17:39 ` Stephen Warren [this message]
2013-02-12 12:29 ` Linus Walleij
2013-02-12 15:59 ` Paul Mundt
2013-02-12 17:18 ` Arnd Bergmann
2013-02-09 13:11 ` Grant Likely
2013-02-09 14:15 ` Alexandre Courbot
2013-02-09 13:24 ` Grant Likely
2013-02-09 14:18 ` Alexandre Courbot
2013-02-02 16:29 ` [PATCH 7/9] gpiolib: let gpio_chip reference its descriptors Alexandre Courbot
2013-02-05 18:00 ` Linus Walleij
2013-02-09 13:28 ` Grant Likely
2013-02-02 16:29 ` [PATCH 8/9] gpiolib: use gpio_chips list in gpio_to_desc Alexandre Courbot
2013-02-05 18:01 ` Linus Walleij
2013-02-09 9:58 ` Grant Likely
2013-02-09 14:21 ` Alexandre Courbot
2013-02-09 14:37 ` Grant Likely
2013-02-02 16:29 ` [PATCH 9/9] gpiolib: dynamically allocate descriptors array Alexandre Courbot
2013-02-05 18:02 ` Linus Walleij
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=51192CC5.9060300@wwwdotorg.org \
--to=swarren@wwwdotorg.org \
--cc=acourbot@nvidia.com \
--cc=arnd@arndb.de \
--cc=broonie@opensource.wolfsonmicro.com \
--cc=gnurou@gmail.com \
--cc=grant.likely@secretlab.ca \
--cc=linus.walleij@linaro.org \
--cc=linux-arch@vger.kernel.org \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=mturquette@linaro.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).