Re: [PATCH] ARM: dts: da850: Add missing pin muxing for the UARTs

[Karl Beldan <kbeldan@baylibre.com>]

On Tue, Aug 23, 2016 at 04:46:03PM +0530, Sekhar Nori wrote:
> On Tuesday 23 August 2016 04:39 PM, Sekhar Nori wrote:
> > On Friday 05 August 2016 04:30 AM, Kevin Hilman wrote:
> >> Karl Beldan <kbeldan@baylibre.com> writes:
> >>
> >>> On Thu, Aug 04, 2016 at 12:20:27PM -0700, Kevin Hilman wrote:
> >>>> Karl Beldan <kbeldan@baylibre.com> writes:
> >>>>
> >>>>> This adds 2 pinctrl groups (rtscts, rxtx) for each of the 3 UARTs.
> >>>>>
> >>>>> Signed-off-by: Karl Beldan <kbeldan@baylibre.com>
> >>>>
> >>>> Should da850-evm be updated to use the serial2_rxtx_pins also?
> >>>>
> >>> I could not find the EVM schematics on the net and I only have an LCDK,
> >>> but according to the code it should, however I can't tell whether flow
> >>> control pins are used.
> >>
> >> Ok, let's just leave it for now, since it's working fine.  Sekhar can
> >> fix that up if he can dig up the schematics.
> > 
> > Looks like the flow control pins are being used for McASP also on the
> > EVM. So lets leave the EVM as-is.
> 
> Rather, the EVM dts file should be updated to use serial2_rxtx_pins like
> the LCDK. Right now it seems to be relying on bootloader to serial2
> setup pimux correctly. I can make a patch to fix that. Or if you can do
> it, that will be great too.
> 

Indeed ATM the EVM relies on the bootloader to setup the pin muxing.

I just checked the uart pins routing of the EVM, the dts:
- should reclaim serial2_rxtx_pins and serial2_rtscts_pins
- can reclaim serial1_rxtx_pins (out on Audio connector but very
  unlikely used for audio)
- should leave serial1_rtscts_pins (out on Audio connector but used by
  McASP so used for audio)

Also I think it would be better for the serial nodes to reclaim the rxtx
pins in the dtsi, and override the reclaimed pins in the .dts only for
the nodes reclaiming flow control (some other pins could also be
directly reclaimed in the dtsi).

Some other cleanups would also be in order for the da850*:
- use labels for non dtsi (like I did for the LCDK)
- add chosen,memory nodes (I guess currently only the LCDK can
  dispense with ATAGS)
- use a null range translation in the da850 dtsi for the soc node
  (computing the offsets is error prone and is there a point)

Sure I could fix that, along with some of the above suggestions if you
are ok with it.

Rgds, 
Karl