From: Ezequiel Garcia <ezequiel@collabora.com>
To: Dong Aisheng <dongas86@gmail.com>,
Mirela Rabulea <mirela.rabulea@nxp.com>
Cc: "linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>,
"mchehab@kernel.org" <mchehab@kernel.org>,
"shawnguo@kernel.org" <shawnguo@kernel.org>,
"robh+dt@kernel.org" <robh+dt@kernel.org>,
Aisheng Dong <aisheng.dong@nxp.com>,
"G.n. Zhou" <guoniu.zhou@nxp.com>,
dl-linux-imx <linux-imx@nxp.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Laurentiu Palcu <laurentiu.palcu@nxp.com>,
"linux-media@vger.kernel.org" <linux-media@vger.kernel.org>,
"paul.kocialkowski@bootlin.com" <paul.kocialkowski@bootlin.com>,
"devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
Robert Chiras <robert.chiras@nxp.com>,
"p.zabel@pengutronix.de" <p.zabel@pengutronix.de>,
Peng Fan <peng.fan@nxp.com>,
"hverkuil-cisco@xs4all.nl" <hverkuil-cisco@xs4all.nl>,
Daniel Baluta <daniel.baluta@nxp.com>,
"kernel@pengutronix.de" <kernel@pengutronix.de>,
"s.hauer@pengutronix.de" <s.hauer@pengutronix.de>
Subject: Re: [PATCH v13 2/2] arm64: dts: imx: Add jpeg encoder/decoder nodes
Date: Fri, 11 Jun 2021 12:00:59 -0300 [thread overview]
Message-ID: <15d5728aeb7895f81f833e7f7e281861c1fcef9a.camel@collabora.com> (raw)
In-Reply-To: <CAA+hA=TEi3iZ+nOfff=aN1FrLGb6+OHfx23aWaa1J7YfZRRgtA@mail.gmail.com>
On Fri, 2021-06-11 at 21:33 +0800, Dong Aisheng wrote:
> [...]
>
> > > > +img_subsys: bus@58000000 {
> > > > + compatible = "simple-bus";
> > > > + #address-cells = <1>;
> > > > + #size-cells = <1>;
> > > > + ranges = <0x58000000 0x0 0x58000000 0x1000000>;
> > > > +
> > > > + img_ipg_clk: clock-img-ipg {
> > > > + compatible = "fixed-clock";
> > > > + #clock-cells = <0>;
> > > > + clock-frequency = <200000000>;
> > > > + clock-output-names = "img_ipg_clk";
> > > > + };
> > > > +
> > > > + jpegdec: jpegdec@58400000 {
> > >
> > > Node should be disabled by default.
> > > And enable it in board dts including LPCG.
> >
> > At version v5 of this patch, the node was disabled by default, and I
> > received this feedback from Ezequiel Garcia:
> >
> > "Pure memory-to-memory are typically not enabled per-board, but just
> > per-platform.
> > So you can drop the disabled status here."
> >
> > So, in v6 I made it enabled by default.
> >
> > Any strong reasons for enabled/disabled per platform?
>
> AFAIK we usually only enable system basic features and let other
> user selectable features disabled by default in dts.
> Even for device LPCG clocks, if it's enabled by default and later
> enter runtime suspend if no users, it still consumes power.
>
Well-written drivers shouldn't draw any power if not used.
And DT is about hardware-description, not about usage-description.
Which means, at the soc.dtsi level you disable devices that need
some board-level hardware thing to be enabled (e.g. a physical
connected, a regulator, etc.).
A pure memory-to-memory should be enabled by default, because
in practice you can't predict what the users a board will want
to use, nor the DT is the place for that.
Sticking to hardware description is the best way to get DT right :-)
Cheers,
Ezequiel
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next prev parent reply other threads:[~2021-06-11 15:03 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-22 21:10 [PATCH v13 0/2] Add dts and bindings update for i.MX8QM/QXP JPEG codec Mirela Rabulea (OSS)
2021-05-22 21:10 ` [PATCH v13 1/2] media: dt-bindings: imx-jpeg: Add compatible for i.MX8QM " Mirela Rabulea (OSS)
2021-05-24 3:19 ` Aisheng Dong
2021-05-22 21:10 ` [PATCH v13 2/2] arm64: dts: imx: Add jpeg encoder/decoder nodes Mirela Rabulea (OSS)
2021-05-24 3:28 ` Aisheng Dong
2021-05-24 7:17 ` Mirela Rabulea
2021-06-11 13:33 ` Dong Aisheng
2021-06-11 15:00 ` Ezequiel Garcia [this message]
2021-06-18 12:47 ` Dong Aisheng
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