[PATCH 2/9] ARM: dts: imx6sl: remove the use of pingrp macros

On Tuesday, 28. January 2014 19:20:49 Shawn Guo wrote:

On Tue, Jan 28, 2014 at 11:17:22AM +0100, Heiko St?bner wrote:

quoted

[... and so on for the other groups ... ]

I'm confused now :-) . Current linux-next [0] shows the pin-settings as
part of imx6sl.dtsi - a way a lot of other architectures organize their
pingroups too, with the board file only referencing the relevant
pingroups from the predefined ones of the soc.

So I guess your move to the pingrp-header moved them out of the
imx6sl.dtsi to the .h and is not part of linux-next;

Yes, my for-next branch was excluded from linux-next temporarily for
some reason.  I will ask Stephen to add it back once v3.14-rc1 is out.
That said, you can see nothing we developed in this cycle on linux-next
for now.

quoted

but this patch (and the others in this
series) now moves the definitions into the individual board files. Can't
you just move them back to the soc-dtsi files to prevent each board
duplicating them?

No.  That will bring back the problem we try to solve from the
beginning [1].

[1] http://thread.gmane.org/gmane.linux.ports.arm.kernel/275912/

Thanks for the pointer, I think I understand the issue now :-) .

So for the short term, I should probably also define the pingroups in my board-
dts then.


But as an insane idea that I just had, because the issue will probably affect 
more architectures at some point when their pingroups or other common-nodes 
grow, how about introducing something like a "/delete-if-unreferenced/" prefix 
in dtc?

As I could see in [0], adding something to dtc is not as far off as I thought.

In essence one would add the pingroups to the soc dtsi, like

		ecspi1 {
			/delete-if-unreferenced/ pinctrl_ecspi1_1: ecspi1grp-1 {
				fsl,pins = <
					MX6SL_PAD_ECSPI1_MISO__ECSPI1_MISO 0x100b1
					MX6SL_PAD_ECSPI1_MOSI__ECSPI1_MOSI 0x100b1
					MX6SL_PAD_ECSPI1_SCLK__ECSPI1_SCLK 0x100b1
				>;
			};
		};

and dtc would then be tasked with checking if the node gets referenced in a 
phandle somewhere in the dts and if not removing it.

I don't know if this is at all sane to think about or doable in dtc.


Heiko

[0] http://www.spinics.net/lists/arm-kernel/msg300936.html