[U-Boot] [PATCH v2] of-platdata: improve documentation

[Adam Ford]

On Mon, Jan 21, 2019 at 12:26 PM <sjg at google.com> wrote:
>
> On Wed, 16 Jan 2019 at 12:40, Simon Goldschmidt
> <simon.k.r.goldschmidt at gmail.com> wrote:
> >
> > Improve some things in the documentation of OF_PLATDATA that I found
> > while porting socfgpa_gen5 to it.

Thanks for doing that.  I actually learned a bit.  :-)

This may be more directed at Simon, but it seems like many platforms
are limited in SPL and OF_PLATDATA might be a great feature to get
more drivers supporting device tree booting without as much overhead.

>From how the documentation reads, it seems like the drivers may not
necessarily support OF_PLATDATA by default.  I've been struggling
trying to enable basic functions (like serial via 16550 driver)
because the platform data generated doesn't necessarily match the
platform data I use to start the serial device.  I would like to
migrate from using manually entered platform data to using OF_PLATDATA
to reduce the overhead.

A few things I noticed are that the generated device names correspond
to the names listed in the 'compatible' flag and there doesn't seem to
be a good way to link them to the actual driver name.

I see a few drivers that check for OF_PLATDATA, but I am not seeing
many people actually utilize this feature.  Any suggestions on how to
one might migrate a driver (like serial) which already supports
OF_CONTROL in u-boot, but the generated platdata doesn't boot in SPL?

adam
> >
> > Signed-off-by: Simon Goldschmidt <simon.k.r.goldschmidt at gmail.com>
> > ---
> >
> > Changes in v2:
> > - further fixes noted by Simon Glass
> > - added info about missing node relations
> > - moved the passage about phandles into section 'caveats'
> >
> >  doc/driver-model/of-plat.txt | 31 ++++++++++++++++++++-----------
> >  dts/Kconfig                  |  6 ++----
> >  2 files changed, 22 insertions(+), 15 deletions(-)
>
> Reviewed-by: Simon Glass <sjg at chromium.org>
>
> Applied to u-boot-dm, thanks!
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