From: Shawn Guo <shawnguo@kernel.org>
To: Anson Huang <anson.huang@nxp.com>,
Vincent Guittot <vincent.guittot@linaro.org>
Cc: "mark.rutland@arm.com" <mark.rutland@arm.com>,
"devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
"s.hauer@pengutronix.de" <s.hauer@pengutronix.de>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"robh+dt@kernel.org" <robh+dt@kernel.org>,
dl-linux-imx <linux-imx@nxp.com>,
"kernel@pengutronix.de" <kernel@pengutronix.de>,
"festevam@gmail.com" <festevam@gmail.com>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH] ARM: dts: imx7ulp: Add cpu clock-frequency property
Date: Wed, 4 Dec 2019 10:02:37 +0800 [thread overview]
Message-ID: <20191204020236.GK9767@dragon> (raw)
In-Reply-To: <DB3PR0402MB39164DF380E6B13558E758E7F5420@DB3PR0402MB3916.eurprd04.prod.outlook.com>
+ Vincent
On Tue, Dec 03, 2019 at 01:09:22AM +0000, Anson Huang wrote:
>
> > Subject: Re: [PATCH] ARM: dts: imx7ulp: Add cpu clock-frequency property
> >
> > On Tue, Nov 05, 2019 at 09:49:38AM +0800, Anson Huang wrote:
> > > Add "clock-frequency" property to avoid below warning on i.MX7ULP:
> > >
> > > [ 0.011762] /cpus/cpu@0 missing clock-frequency property
> > >
> > > Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
> > > ---
> > > arch/arm/boot/dts/imx7ulp.dtsi | 1 +
> > > 1 file changed, 1 insertion(+)
> > >
> > > diff --git a/arch/arm/boot/dts/imx7ulp.dtsi
> > > b/arch/arm/boot/dts/imx7ulp.dtsi index d37a192..87b2237 100644
> > > --- a/arch/arm/boot/dts/imx7ulp.dtsi
> > > +++ b/arch/arm/boot/dts/imx7ulp.dtsi
> > > @@ -41,6 +41,7 @@
> > > compatible = "arm,cortex-a7";
> > > device_type = "cpu";
> > > reg = <0>;
> > > + clock-frequency = <500210526>;
> >
> > I cannot find the binding doc for this property. What is the definition of it,
> > the maximum frequency that the cpu could possibly run at?
>
>
> The code is as below, maybe the property is missing from the beginning of this code,
> this property should mean the current frequency of CPU running at I think:
>
> arch/arm/kernel/topology.c
>
> 122 rate = of_get_property(cn, "clock-frequency", &len);
> 123 if (!rate || len != 4) {
> 124 pr_err("%pOF missing clock-frequency property\n", cn);
> 125 continue;
> 126 }
Yes, I can find the code, but not bindings for it. Considering
frequency of a CPU can be scaled in a quite wide range, we need
a clear understanding on this property. IIUIC, the property is used to
calculate the capacity of CPU, it should be the maximum frequency the
CPU could possibly scale to?
Shawn
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
prev parent reply other threads:[~2019-12-04 2:02 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-05 1:49 [PATCH] ARM: dts: imx7ulp: Add cpu clock-frequency property Anson Huang
2019-12-02 13:47 ` Shawn Guo
2019-12-03 1:09 ` Anson Huang
2019-12-04 2:02 ` Shawn Guo [this message]
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=20191204020236.GK9767@dragon \
--to=shawnguo@kernel.org \
--cc=anson.huang@nxp.com \
--cc=devicetree@vger.kernel.org \
--cc=festevam@gmail.com \
--cc=kernel@pengutronix.de \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-imx@nxp.com \
--cc=linux-kernel@vger.kernel.org \
--cc=mark.rutland@arm.com \
--cc=robh+dt@kernel.org \
--cc=s.hauer@pengutronix.de \
--cc=vincent.guittot@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).