DT include files (was: [GIT PULL 2/2] ARM: imx: device tree changes for 3.14)

On Thu, Jan 2, 2014 at 6:32 PM, Shawn Guo [off-list ref] wrote:

Hi Olof,

On Thu, Jan 02, 2014 at 12:21:08PM -0800, Olof Johansson wrote:

quoted

quoted

 .../devicetree/bindings/vendor-prefixes.txt        |    3 +
 arch/arm/boot/dts/imx25-pinfunc.h                  |  494 +++++++++++
 arch/arm/boot/dts/imx25-pingrp.h                   |   81 ++
 arch/arm/boot/dts/imx27-pinfunc.h                  |  526 +++++++++++
 arch/arm/boot/dts/imx27-pingrp.h                   |  151 ++++
 arch/arm/boot/dts/imx35-pingrp.h                   |  104 +++
 arch/arm/boot/dts/imx50-pinfunc.h                  |  923 ++++++++++++++++++++
 arch/arm/boot/dts/imx50-pingrp.h                   |  146 ++++
 arch/arm/boot/dts/imx51-pingrp.h                   |  249 ++++++
 arch/arm/boot/dts/imx53-pingrp.h                   |  352 ++++++++
 arch/arm/boot/dts/imx6dl-pinfunc.h                 |    2 +
 arch/arm/boot/dts/imx6q-pinfunc.h                  |    2 +
 arch/arm/boot/dts/imx6qdl-pingrp.h                 |  532 +++++++++++
 arch/arm/boot/dts/imx6sl-pingrp.h                  |  148 ++++
 arch/arm/boot/dts/vf610-pingrp.h                   |  127 +++

Hm, these don't quite use include files the way include files were
originally meant to be used -- initially the idea was to use them to
define mostly simple constants instead of full properties like this.

The DT macro support was introduced to improve the readability of device
tree sources by replacing those magic numbers with readable macros.  I
think the usage in imx pinctrl binding perfectly fits the purpose.  You
can get details of the binding in
Documentation/devicetree/bindings/pinctrl/fsl,imx-pinctrl.txt.

To be honest I didn't follow that discussion closely. If DT
maintainers are OK with that style, then I'm OK. :)

quoted

I'm not against the idea of using it this way, but I also want to make sure the
DT maintainers are OK with it. So I've cc:d them on this reply.

This is not a new thing. It was firstly adopted for imx6q in v3.10
release with commit e164153 (pinctrl: imx: move hard-coding data into
device tree), which had been posted to devicetree list for sure.  We're
just moving more i.MX SoCs to it.

Ok, then it's probably just the location of the header files that
should be adjusted. Other subsystems have placed them under
include/dt-bindings/<subsystem>, so that's likely a better place for
these as well, don't you think?

quoted

I'm also not crazy about the insanely long identifiers used here, but I guess
they correlate with some user manual tables?

Yes, the identifiers follows the pad and function names from reference
manual.

Ok, fair enough.


-Olof