From: grant.likely@secretlab.ca (Grant Likely)
To: linux-arm-kernel@lists.infradead.org
Subject: ACPI
Date: Tue, 26 Nov 2013 12:55:10 +0000 [thread overview]
Message-ID: <CACxGe6t_9hUXL_1PHRU=2DYOYfCqZykd7gYRCshZn0XsVoCdRw@mail.gmail.com> (raw)
In-Reply-To: <CACRpkdY+6dzs8MpKKtW-3kzsLkZjsit9SeN20k_33TAtVf3NEA@mail.gmail.com>
On Tue, Nov 26, 2013 at 12:43 PM, Linus Walleij
<linus.walleij@linaro.org> wrote:
> On Mon, Nov 25, 2013 at 4:41 PM, Matthew Garrett <mjg59@srcf.ucam.org> wrote:
>
>> In the past ACPI implementations handled GPIO by providing
>> methods that accessed hardware registers directly. I've seen DSDTs that
>> implement i2c entirely in ASL.
>
> Is that common?
>
> Since i2c is a slow bus, can be 100kHz or so, how does that
> avoid locking the entire CPU while e.g. waiting for transactions on
> the external bus to complete?
>
> In I2C drivers we typically use completion IRQs so that we can
> do other stuff when the I2C traffic is busy ...
>
> I have a feeling we should not recommend ARM implementers
> to go and do things like this.
ACPI5 defines a binding for serial busses (i2c & spi) which allows
real device drivers to drive the bus and allows ACPI and the kernel to
share the bus safely. Using that binding means some i2c devices can be
'owned' by ACPI and others owned by the kernel.
g.
next prev parent reply other threads:[~2013-11-26 12:55 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-11-18 18:42 ACPI Jon Masters
[not found] ` < CACRpkdY+6dzs8MpKKtW-3kzsLkZjsit9SeN20k_33TAtVf3NEA@mail.gmail.com>
[not found] ` < CACxGe6t_9hUXL_1PHRU=2DYOYfCqZykd7gYRCshZn0XsVoCdRw@mail.gmail.com>
[not found] ` < 20131126183344.GA16074@srcf.ucam.org>
[not found] ` < CACRpkdbNxxNK0GM28H_nDLu6EpbQ-EYAdEeTp5fnXW5mkEPkgw@mail.gmail.com>
[not found] ` < CACxGe6uHuWPh7d9NaVuPRBWq0Fh1BmDV190KEN4C4uaq4KjS8g@mail.gmail.com>
[not found] ` < CACRpkdaCXJzWXoesjD3Jqpm4XMHLQp3SsHcsDG3veUS+xarqHQ@mail.gmail.com>
[not found] ` < CACxGe6vUKzow7QpeX2mU7CiZQzY8aZ+p0jd8Vk0+dqz0B=D0Ew@mail.gmail.com>
2013-11-19 18:15 ` ACPI Arnd Bergmann
2013-11-21 20:03 ` ACPI Mark Brown
2013-11-22 0:29 ` ACPI Arnd Bergmann
2013-11-22 4:05 ` ACPI Jon Masters
2013-11-22 20:31 ` ACPI Arnd Bergmann
2013-11-22 20:59 ` ACPI Jon Masters
2013-11-22 21:37 ` ACPI Jon Masters
2013-11-23 9:11 ` ACPI Arnd Bergmann
2013-11-23 18:39 ` ACPI Jason Gunthorpe
2013-11-23 23:03 ` ACPI Matthew Garrett
2013-11-24 3:52 ` ACPI Jon Masters
2013-11-24 3:56 ` ACPI Matthew Garrett
2013-11-24 23:21 ` ACPI Jon Masters
2013-11-24 23:40 ` ACPI Matthew Garrett
2013-11-22 13:19 ` ACPI Mark Brown
2013-11-19 18:28 ` ACPI Måns Rullgård
2013-11-21 16:56 ` ACPI Matthew Garrett
2013-11-24 17:14 ` ACPI Linus Walleij
2013-11-25 0:42 ` ACPI Grant Likely
2013-11-25 1:28 ` ACPI Matthew Garrett
2013-11-25 11:07 ` ACPI Linus Walleij
2013-11-25 11:33 ` ACPI Grant Likely
2013-11-25 15:41 ` ACPI Matthew Garrett
2013-11-26 12:43 ` ACPI Linus Walleij
2013-11-26 12:55 ` Grant Likely [this message]
2013-11-26 13:43 ` ACPI Jürgen Beisert
2013-11-27 12:25 ` ACPI Grant Likely
2013-11-28 13:16 ` ACPI Linus Walleij
2013-11-26 18:33 ` ACPI Matthew Garrett
2013-11-26 23:11 ` ACPI Matt Sealey
2013-11-26 23:32 ` ACPI Matthew Garrett
2013-11-27 11:00 ` ACPI Catalin Marinas
2013-11-27 22:12 ` ACPI Nicolas Pitre
2013-11-27 20:21 ` ACPI Matt Sealey
2013-11-28 6:21 ` ACPI Jon Masters
2013-11-28 18:26 ` ACPI Stefano Stabellini
2013-11-28 18:48 ` ACPI Matthew Garrett
2013-11-28 18:51 ` ACPI Stefano Stabellini
2013-11-27 14:16 ` ACPI Grant Likely
2013-11-27 22:17 ` ACPI Matt Sealey
2013-11-28 13:50 ` ACPI Leif Lindholm
2013-11-28 15:43 ` ACPI Grant Likely
2013-11-27 12:41 ` ACPI Grant Likely
2013-11-26 14:45 ` ACPI Matthew Garrett
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