From: Mike Turquette <mturquette@ti.com>
To: linux-arm-kernel@lists.infradead.org
Subject: Re: Device tree binding for DVFS table
Date: Wed, 11 Jul 2012 20:04:02 +0000 [thread overview]
Message-ID: <20120711200402.GC2772@gmail.com> (raw)
In-Reply-To: <20120711144449.GA23654@sirena.org.uk>
On 20120711-15:44, Mark Brown wrote:
> On Wed, Jul 11, 2012 at 09:03:41AM -0500, Rob Herring wrote:
>
> > I'd expect a single property with freq/volt pairs or 2 properties for
> > freq and voltage where there is a 1:1 relationship (freq N uses voltage N).
>
> I strongly agree - the current proposal is very hard to read due to the
> separation between the voltage and frequency values. Some devices do
> also need to scale multiple rails together, especially when this gets
> used for I/O devices.
>
> I'd also expect to see a range of voltages for each frequency rather
> than a specific voltage; usually things are at least characterised with
> a specified tolerance.
Not only should we support multiple voltage rails but also multiple
clocks. For some devices a DVFS transition is composed of scaling
multiple clock rates together. So some sort of clock identifier
(phandle?) is needed as well. (forgive my ignorance on the phandle
part, as I am a DT noob)
Regards,
Mike
WARNING: multiple messages have this Message-ID (diff)
From: mturquette@ti.com (Mike Turquette)
To: linux-arm-kernel@lists.infradead.org
Subject: Device tree binding for DVFS table
Date: Wed, 11 Jul 2012 13:04:02 -0700 [thread overview]
Message-ID: <20120711200402.GC2772@gmail.com> (raw)
In-Reply-To: <20120711144449.GA23654@sirena.org.uk>
On 20120711-15:44, Mark Brown wrote:
> On Wed, Jul 11, 2012 at 09:03:41AM -0500, Rob Herring wrote:
>
> > I'd expect a single property with freq/volt pairs or 2 properties for
> > freq and voltage where there is a 1:1 relationship (freq N uses voltage N).
>
> I strongly agree - the current proposal is very hard to read due to the
> separation between the voltage and frequency values. Some devices do
> also need to scale multiple rails together, especially when this gets
> used for I/O devices.
>
> I'd also expect to see a range of voltages for each frequency rather
> than a specific voltage; usually things are at least characterised with
> a specified tolerance.
Not only should we support multiple voltage rails but also multiple
clocks. For some devices a DVFS transition is composed of scaling
multiple clock rates together. So some sort of clock identifier
(phandle?) is needed as well. (forgive my ignorance on the phandle
part, as I am a DT noob)
Regards,
Mike
next prev parent reply other threads:[~2012-07-11 20:04 UTC|newest]
Thread overview: 60+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-07-11 12:56 Device tree binding for DVFS table Prashant Gaikwad
2012-07-11 13:08 ` Prashant Gaikwad
2012-07-11 14:03 ` Rob Herring
2012-07-11 14:03 ` Rob Herring
2012-07-11 14:44 ` Mark Brown
2012-07-11 14:44 ` Mark Brown
2012-07-11 20:04 ` Mike Turquette [this message]
2012-07-11 20:04 ` Mike Turquette
2012-07-12 4:14 ` Prashant Gaikwad
2012-07-12 4:26 ` Prashant Gaikwad
2012-07-12 14:10 ` Peter De Schrijver
2012-07-12 14:10 ` Peter De Schrijver
2012-07-12 17:10 ` Mike Turquette
2012-07-12 17:10 ` Mike Turquette
2012-07-12 17:15 ` Mark Brown
2012-07-12 17:15 ` Mark Brown
2012-07-13 10:34 ` Peter De Schrijver
2012-07-13 10:34 ` Peter De Schrijver
2012-07-13 17:25 ` Mike Turquette
2012-07-13 17:25 ` Mike Turquette
2012-07-12 4:17 ` Prashant Gaikwad
2012-07-12 4:29 ` Prashant Gaikwad
2012-07-12 15:23 ` Mark Brown
2012-07-12 15:23 ` Mark Brown
2012-07-12 17:01 ` Mike Turquette
2012-07-12 17:01 ` Mike Turquette
2012-07-12 8:19 ` Peter De Schrijver
2012-07-12 8:19 ` Peter De Schrijver
2012-07-12 4:08 ` Prashant Gaikwad
2012-07-12 4:20 ` Prashant Gaikwad
2012-07-13 18:30 ` Prashant Gaikwad
2012-07-13 18:42 ` Prashant Gaikwad
2012-07-15 21:40 ` Mark Brown
2012-07-15 21:40 ` Mark Brown
2012-07-15 23:42 ` Rob Herring
2012-07-15 23:42 ` Rob Herring
2012-07-16 18:36 ` Turquette, Mike
2012-07-16 18:36 ` Turquette, Mike
2012-07-17 12:37 ` Prashant Gaikwad
2012-07-17 12:49 ` Prashant Gaikwad
2012-07-17 13:20 ` Mark Brown
2012-07-17 13:20 ` Mark Brown
2012-07-17 14:22 ` Prashant Gaikwad
2012-07-17 14:34 ` Prashant Gaikwad
2012-07-17 14:37 ` Mark Brown
2012-07-17 14:37 ` Mark Brown
2012-07-18 12:46 ` Prashant Gaikwad
2012-07-18 12:58 ` Prashant Gaikwad
2012-07-18 21:19 ` Mark Brown
2012-07-18 21:19 ` Mark Brown
2012-07-18 17:08 ` Shawn Guo
2012-07-18 17:08 ` Shawn Guo
2012-07-11 13:08 함명주
2012-07-11 13:08 ` 함명주
2012-07-11 13:49 ` Peter De Schrijver
2012-07-11 13:49 ` Peter De Schrijver
2012-07-11 13:49 ` Peter De Schrijver
2012-07-11 13:49 ` Peter De Schrijver
2012-07-12 4:22 ` Prashant Gaikwad
2012-07-12 4:34 ` Prashant Gaikwad
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=20120711200402.GC2772@gmail.com \
--to=mturquette@ti.com \
--cc=linux-arm-kernel@lists.infradead.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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.