From: Jan Kiszka <jan.kiszka@siemens.com>
To: Linus Walleij <linus.walleij@linaro.org>,
Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Cc: Mika Westerberg <mika.westerberg@linux.intel.com>,
Bartosz Golaszewski <bgolaszewski@baylibre.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
"open list:GPIO SUBSYSTEM" <linux-gpio@vger.kernel.org>,
ACPI Devel Maling List <linux-acpi@vger.kernel.org>,
"Rafael J. Wysocki" <rafael.j.wysocki@intel.com>
Subject: Re: [PATCH 2/2] gpio: sch: Add interrupt support
Date: Fri, 26 Apr 2019 17:44:10 +0200 [thread overview]
Message-ID: <63b179c9-242d-ae90-9c33-49ed256bde28@siemens.com> (raw)
In-Reply-To: <CACRpkdY=m1QJVqvERiAY+7taUgjPXn=9U2Eajx7d7NPo-iNhiA@mail.gmail.com>
On 26.04.19 16:41, Linus Walleij wrote:
> On Fri, Apr 26, 2019 at 3:06 PM Andy Shevchenko
> <andriy.shevchenko@linux.intel.com> wrote:
>> On Wed, Apr 24, 2019 at 12:39:35PM +0200, Jan Kiszka wrote:
>>> On 24.04.19 12:33, Mika Westerberg wrote:
>>>> On Wed, Apr 24, 2019 at 12:19:02PM +0200, Jan Kiszka wrote:
>>
>>>>> And even if that were possible, we would be back to the square of existing
>>>>> devices without those definitions. If this were a recent chipset, I would
>>>>> say, "go, fix future firmware versions". But this one is legacy.
>>>>
>>>> Is it fixing some real issue with these legacy platforms? I mean without
>>>> the patch some GPE event is not handled properly? It was not clear to me
>>>> from the commit message.
>>>>
>>>
>>> Without that patch, you are forced to poll for event changes in your
>>> application, timer-driven. There are application that cannot process these
>>> GPIOs because they lack such logic (mraa with node-red-node-intel-gpio is a
>>> public example).
>>
>> Just a side note: MRAA is a hack itself. It abuses almost all interfaces Linux
>> kernel provides.
>
> I think it's pretty clean for GPIOs these days. My colleague Manivannan
> was part of cleaning it up a while back and since then it is doing
> what userspace should be doing if userspace absolutely cannot
> abstain from using GPIOs directly (i.e. uses the character device).
> https://github.com/intel-iot-devkit/mraa/blob/master/src/gpio/gpio_chardev.c
>
> I don't know about other resources than GPIOs though.
That's valuable progress!
OTOH, there still seem to be the broken pattern to address pins via hard-coded
GPIO numbers. This broke our neck, e.g., when trying to replace the hacky BSP
kernel with upstream. I started to create better infrastructure but never fished
that.
Thanks,
Jan
--
Siemens AG, Corporate Technology, CT RDA IOT SES-DE
Corporate Competence Center Embedded Linux
prev parent reply other threads:[~2019-04-26 15:44 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-04-18 9:23 [PATCH 0/2] gpio: sch: Interrupt support Jan Kiszka
2019-04-18 9:23 ` [PATCH 1/2] gpio: sch: Remove write-only core_base Jan Kiszka
2019-04-23 11:09 ` Linus Walleij
2019-04-18 9:23 ` [PATCH 2/2] gpio: sch: Add interrupt support Jan Kiszka
2019-04-23 11:10 ` Linus Walleij
2019-04-24 7:58 ` Mika Westerberg
2019-04-24 8:12 ` Jan Kiszka
2019-04-24 8:18 ` Mika Westerberg
2019-04-24 8:25 ` Jan Kiszka
2019-04-24 8:42 ` Mika Westerberg
2019-04-24 9:36 ` Jan Kiszka
2019-04-24 9:45 ` Mika Westerberg
2019-04-24 9:48 ` Jan Kiszka
2019-04-24 10:01 ` Mika Westerberg
2019-04-24 10:19 ` Jan Kiszka
2019-04-24 10:33 ` Mika Westerberg
2019-04-24 10:39 ` Jan Kiszka
2019-04-24 10:46 ` Mika Westerberg
2019-04-24 12:41 ` Jan Kiszka
2019-04-24 13:13 ` Mika Westerberg
2019-04-24 14:24 ` Jan Kiszka
2019-04-24 15:33 ` Mika Westerberg
2019-04-26 13:06 ` Andy Shevchenko
2019-04-26 13:36 ` Jan Kiszka
2019-04-26 14:42 ` Enrico Weigelt, metux IT consult
2019-04-26 15:31 ` Manivannan Sadhasivam
2019-04-26 16:03 ` Jan Kiszka
2019-04-26 17:20 ` Andy Shevchenko
2019-04-26 17:33 ` Manivannan Sadhasivam
2019-04-26 17:39 ` Jan Kiszka
2019-04-26 17:46 ` Manivannan Sadhasivam
2019-04-26 17:52 ` Jan Kiszka
2019-04-26 17:56 ` Manivannan Sadhasivam
2019-04-26 17:44 ` Andy Shevchenko
2019-04-26 17:52 ` Manivannan Sadhasivam
2019-04-26 18:26 ` Andy Shevchenko
2019-04-26 17:37 ` Jan Kiszka
2019-04-29 11:09 ` Enrico Weigelt, metux IT consult
2019-05-16 12:20 ` Linus Walleij
2019-04-26 14:41 ` Linus Walleij
2019-04-26 15:44 ` Jan Kiszka [this message]
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