From: Tony Lindgren <tony@atomide.com>
To: Shawn Guo <shawn.guo@linaro.org>
Cc: Simon Glass <sjg@chromium.org>,
Stephen Warren <swarren@nvidia.com>,
Dong Aisheng-B29396 <B29396@freescale.com>,
"Linus Walleij (linus.walleij@linaro.org)"
<linus.walleij@linaro.org>,
"Sascha Hauer (s.hauer@pengutronix.de)" <s.hauer@pengutronix.de>,
"rob.herring@calxeda.com" <rob.herring@calxeda.com>,
"kernel@pengutronix.de" <kernel@pengutronix.de>,
"cjb@laptop.org" <cjb@laptop.org>,
Dong Aisheng <dongas86@gmail.com>,
Thomas Abraham <thomas.abraham@linaro.org>,
"Grant Likely (grant.likely@secretlab.ca)"
<grant.likely@secretlab.ca>,
"devicetree-discuss@lists.ozlabs.org"
<devicetree-discuss@lists.ozlabs.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>
Subject: Re: Pinmux bindings proposal V2
Date: Mon, 30 Jan 2012 09:49:10 -0800 [thread overview]
Message-ID: <20120130174910.GG9339@atomide.com> (raw)
In-Reply-To: <20120130031346.GD10470@S2101-09.ap.freescale.net>
* Shawn Guo <shawn.guo@linaro.org> [120129 18:30]:
> On Fri, Jan 27, 2012 at 07:43:36AM -0800, Simon Glass wrote:
> ...
> > The cost of the pmx@dta node is about 12 bytes for the header (it
> > depends on the length of the name), and each of the properties above
> > is 16 bytes. So in total this node is 76 bytes. If we have 250 pins
> > being muxed as Tegra3 then this is about 20KB (including a bit of
> > slack for longer names). My point about being able to 'optimise out'
> > some of these remains, though, but probably not for the kernel.
> >
> > Stephen's 'mux' property uses 12 bytes plus 8 bytes per pin/group (I
> > am removing the prefixes):
> >
> > mux =
> > <PG_DTA MUX_SDIO1>
> > <PG_DTD MUX_SDIO1>;
> >
> > so 28 bytes. What I proposed would use (12 + 2 * 16) per pin/group, or
> > 44 bytes (60% bigger):
> >
> It's not only about size but also run-time tree travelling efficiency.
> Your proposal requires every single pin show as a node in device tree.
> Looking at these for_each_node_by_*() APIs in include/linux/of.h, you
> might agree we should avoid bloating device tree with so many nodes.
And that's why I'm suggesting two bindings: A minimal pinctrl-static
binding and more verbose pinctrl-dynamic binding.
AFAIK the number of pinctrl-dynamic bindings needed are just a fraction
of the pinctrl-static bindings. So the extra parsing needed for a few
pinctrl-dynamic bindings should not matter.
Sure it would be nice to have it all in a single binding, but these
bindings have conflicting requirements. So it may not be possible to
do it in a single binding in an efficient way.
Regards,
Tony
next prev parent reply other threads:[~2012-01-30 17:49 UTC|newest]
Thread overview: 49+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-01-20 22:22 Pinmux bindings proposal V2 Stephen Warren
2012-01-23 21:00 ` Tony Lindgren
2012-01-23 23:08 ` Stephen Warren
2012-01-24 1:20 ` Tony Lindgren
2012-01-24 22:29 ` Stephen Warren
2012-01-25 0:04 ` Tony Lindgren
2012-01-26 19:33 ` Stephen Warren
2012-01-27 2:08 ` Tony Lindgren
2012-01-27 6:57 ` Shawn Guo
2012-01-27 17:05 ` Tony Lindgren
2012-01-30 1:56 ` Shawn Guo
2012-01-30 17:20 ` Tony Lindgren
2012-01-31 1:32 ` Shawn Guo
2012-01-31 2:29 ` Tony Lindgren
2012-02-01 5:36 ` Shawn Guo
2012-01-27 17:36 ` Stephen Warren
2012-01-27 17:42 ` Tony Lindgren
2012-01-26 9:36 ` Shawn Guo
2012-01-26 17:51 ` Tony Lindgren
2012-01-27 7:19 ` Shawn Guo
2012-01-27 17:16 ` Tony Lindgren
2012-01-30 2:10 ` Shawn Guo
2012-01-30 17:43 ` Tony Lindgren
2012-01-31 1:07 ` Shawn Guo
2012-01-26 9:24 ` Shawn Guo
2012-01-26 17:42 ` Simon Glass
2012-01-27 2:21 ` Tony Lindgren
2012-01-27 15:43 ` Simon Glass
2012-01-27 17:37 ` Tony Lindgren
2012-01-27 17:51 ` Stephen Warren
2012-01-27 18:10 ` Tony Lindgren
2012-01-30 3:27 ` Shawn Guo
2012-01-30 3:13 ` Shawn Guo
2012-01-30 17:49 ` Tony Lindgren [this message]
2012-01-27 17:38 ` Stephen Warren
2012-01-27 17:29 ` Stephen Warren
2012-01-30 2:31 ` Shawn Guo
2012-02-01 14:35 ` Shawn Guo
2012-02-02 18:36 ` Stephen Warren
2012-02-02 20:07 ` Dong Aisheng
2012-02-03 14:02 ` Shawn Guo
2012-02-03 17:21 ` Dong Aisheng
2012-02-03 17:32 ` Tony Lindgren
2012-02-03 18:13 ` Dong Aisheng
2012-02-03 21:05 ` Tony Lindgren
2012-02-04 16:55 ` Dong Aisheng
2012-02-04 17:15 ` Tony Lindgren
2012-02-03 8:46 ` Shawn Guo
2012-02-13 19:58 ` Stephen Warren
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