RE: [PATCH 4/7] arm: dts: r7s72100: Add pin controller node

[Chris Brandt <Chris.Brandt@xxxxxxxxxxx>]

Hi Geert,

On Friday, March 03, 2017, Geert Uytterhoeven wrote:
> > Is it possible to change the number of port pins in the board dts file?
> > For example:
> >   RZ/A1H: P5_0 - P5_10
> >   RZ/A1L: P5_0 - P5_16
> 
> That's 17 pins, not 16?

Oops, I meant P5_15

Looking at the parts, here are the differences:

RZ/A1H    RZ/A1L
------------------
P2_0:15   P2_0:9
P4_0:15   P4_0:7
P5_0:10   P5_0:15
P7_0:15   P7_0:11
P9_0:7    P9_0:5
P10_0:15  none
P11_0:15  none

> > So, in a rza1l-board.dts file I would put:
> >
> > &port5 {
> >         gpio-ranges = <&pinctrl 0 80 16>;
> > }
> >
> > Will this work?
> 
> Yes, overriding should work. But the number of pins is an SoC-property,
> not
> a board-property?

True, but I am trying to figure out how to solve this locally and not make
it an upstream problem.


> Are the differences between RZ/A1H and RZ/A1L just the number of pins?

Yes/No.

Internally, the IP blocks are the same, and located at the same register
addresses, but come out to different port pins due to the RZ/A1L having smaller
packages.

Also, the L has less channels than the H.
For example:
 QSPI: H=2, L=1
  LCD: H=2, L=1
 SCIF: H=8, L=5
  CAN: H=5, L=2

Of course there is some IP that only comes in the H.

This is why I didn't want to associate "names" with the pins in a pfc driver.
I just wanted the board DT to assign a pin to a 'function number'.



> If yes, you could use a hierarchical DTS structure:
> 
> rza1h-<board>.dts:
> 
>     #include "rza1h.dtsi"
> 
>     // board specifics here
> 
> rza1l-<board>.dts:
> 
>     #include "rza1l.dtsi"
> 
>     // board specifics here
> 
> rza1h.dtsi:
> 
>     #include "rza.dtsi"  // r7s72100.dtsi?
> 
>     // base SoC overrides
>     &port5 {
>         gpio-ranges = <&pinctrl 0 80 11>;
>     }
> 
> rza1l.dtsi:
> 
>     #include "rza.dtsi"  // r7s72100.dtsi?
> 
>     // base SoC overrides
>     &port5 {
>         gpio-ranges = <&pinctrl 0 80 16>;
>     }
> 
> Actual naming of DTS files TBD.

OK, so just put the pin differences in the two files. That's a good idea. But,
then that's 2 more files to add upstream.
As the RZ/A series continues, they might keep doing this kind of thing, so I
don't want to get into the habit of adding more and more DT files.

# I wish there was some type of if-else syntax in Device Tree so in the
board file I could just say:

/ {
	model = "RSKRZA1";
	compatible = "renesas,rskrza1", "renesas,r7s72100";

	variant = "rza1l";


> We could also decide to not have rza1h.dtsi, and assume the base dtsi is
> for
> RZ/A1H.

Honestly, I'm fine with RZ/A1H being the flagship upstream SoC since it is a
superset of all the peripherals in RZ/A1M,/A1L,/A1LU,/A1LC. Meaning, this small
difference can be handled in a simple board file addition.

I was thinking I was going to post some DT examples on eLinux.org anyway, so one of
them would just be this RZ/A1L fix.

Cheers

Chris

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