From: Lukas Wunner <lukas@wunner.de>
To: Linus Walleij <linus.walleij@linaro.org>
Cc: Mathias Duckeck <m.duckeck@kunbus.de>,
Phil Elwell <phil@raspberrypi.org>,
"linux-gpio@vger.kernel.org" <linux-gpio@vger.kernel.org>
Subject: Re: [PATCH 2/4] gpio: Introduce ->get_multiple callback
Date: Thu, 31 Aug 2017 17:46:21 +0200 [thread overview]
Message-ID: <20170831154621.GA21777@wunner.de> (raw)
In-Reply-To: <CACRpkdZo5EzJJUwF8uYqchDC1JC3uZnp9LCpR0DxOdy2K4J_wg@mail.gmail.com>
On Thu, Aug 31, 2017 at 03:48:15PM +0200, Linus Walleij wrote:
> On Sun, Aug 27, 2017 at 7:34 PM, Lukas Wunner <lukas@wunner.de> wrote:
> > At least with SPI-attached GPIO controllers, the transmission is never
> > guaranteed to succeed, so errors can occur both for input and output
> > GPIOs. The MAX3191x is input-only and does pass SPI errors back to
> > the caller. Output drivers such as gpio-74x164.c silently ignore
> > SPI errors, which is arguably a problem.
>
> This has historical reasons.
Would you generally be open for allowing errors to be returned from
the set functions as well? The Revolution Pi uses SPI-attached
digital outputs and knowing if access to them fails would be useful.
For consumers, switching the return value from void to int shouldn't
cause any fallout. They just don't check the return value initially.
However the ->set and ->set_multiple callbacks in all the GPIO drivers
would need to be changed, that's where the real work is.
Thanks,
Lukas
next prev parent reply other threads:[~2017-08-31 15:46 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-08-21 13:12 [PATCH 0/4] GPIO driver for Maxim MAX3191x Lukas Wunner
2017-08-21 13:12 ` [PATCH 3/4] dt-bindings: gpio: max3191x: Document new driver Lukas Wunner
2017-08-23 0:48 ` Rob Herring
2017-08-23 9:44 ` Lukas Wunner
[not found] ` <20170823094438.GA12416-JFq808J9C/izQB+pC5nmwQ@public.gmane.org>
2017-08-23 13:03 ` Rob Herring
2017-09-05 8:16 ` Lukas Wunner
2017-10-04 19:31 ` Lukas Wunner
2017-08-21 13:12 ` [PATCH 2/4] gpio: Introduce ->get_multiple callback Lukas Wunner
2017-08-23 7:38 ` Linus Walleij
2017-08-27 17:34 ` Lukas Wunner
2017-08-31 13:48 ` Linus Walleij
2017-08-31 15:46 ` Lukas Wunner [this message]
2017-09-03 14:58 ` Linus Walleij
2017-10-04 20:32 ` Lukas Wunner
2017-10-07 11:23 ` Linus Walleij
2017-10-12 11:15 ` Lukas Wunner
2017-08-21 13:12 ` [PATCH 1/4] bitops: Introduce assign_bit() Lukas Wunner
2017-08-21 16:18 ` Bart Van Assche
2017-08-22 8:30 ` Lukas Wunner
2017-08-22 9:27 ` Peter Zijlstra
2017-08-22 10:04 ` Lukas Wunner
2017-08-23 7:32 ` Linus Walleij
2017-08-23 17:09 ` Bart Van Assche
2017-08-24 19:52 ` Linus Walleij
2017-08-21 13:12 ` [PATCH 4/4] gpio: Add driver for Maxim MAX3191x industrial serializer Lukas Wunner
[not found] ` <df530ae703fcfdf52d27a1b6d19b6d1a4724b103.1503319573.git.lukas-JFq808J9C/izQB+pC5nmwQ@public.gmane.org>
2017-08-23 8:09 ` Linus Walleij
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