Thread (7 messages) 7 messages, 4 authors, 2017-03-20

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

From: jacopo <jacopo@jmondi.org>
Date: 2017-03-20 13:47:55
Also in: linux-gpio, linux-renesas-soc

Hi Chris, Geert,

On Fri, Mar 03, 2017 at 01:24:51PM +0000, Chris Brandt wrote:
Hi Geert,

On Friday, March 03, 2017, Geert Uytterhoeven wrote:
quoted
quoted
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
quoted
quoted
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.

quoted
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'.


quoted
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";

quoted
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.
If we do all agree on having RZ/A1H upstream and let differences
between SoCs to be handled in the BSP/downstream board files, I'll send
v2 targeting that specific SoC only

Thanks
   j
Cheers

Chris
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