Re: [PATCH v3 8/8] arm64: dts: renesas: r9a08g045s33-smarc-pmod: Add overlay for SCIF1

Claudiu Beznea
2024-12-09T12:19:14Z

Hi, Geert,

On 09.12.2024 12:44, Geert Uytterhoeven wrote:
> Hi Claudiu,
>
> On Fri, Nov 15, 2024 at 2:50 PM Claudiu <claudiu.beznea@tuxon.dev> wrote:
>> From: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
>>
>> Add DT overlay for SCIF1 (of the Renesas RZ/G3S SoC) routed through the
>> PMOD1_3A interface available on the Renesas RZ SMARC Carrier II board.
>>
>> Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
>
> Thanks for your patch!
>
>> --- /dev/null
>> +++ b/arch/arm64/boot/dts/renesas/r9a08g045s33-smarc-pmod.dtso
>> @@ -0,0 +1,48 @@
>> +// SPDX-License-Identifier: GPL-2.0
>> +/*
>> + * Device Tree Source for the RZ/G3S SMARC Carrier II EVK PMOD parts
>
> So you plan to describe all 3 PMOD interfaces in a single overlay?
> The board has:
> 1. PMOD0 - Type-2A,
> 2. PMOD1 - Tpye-3A,
> 3. PMOD1 - Type 6A.
> Wouldn't it be more convenient to have separate overlays for each port,
> so you can more easily use them as e.g. Type-1(A) (GPIO only)?

That would be better, indeed.

>
> BTW, naming both the second and third port "PMOD1" in the schematics,
> and differentiating them by their type, was definitely a bad idea.
> How can you distinguish between Type-1(A) on the second or third port?
>
>> + *
>> + * Copyright (C) 2024 Renesas Electronics Corp.
>> + *
>> + *
>> + * [Connection]
>> + *
>> + * SMARC Carrier II EVK
>> + * +--------------------------------------------+
>> + * |PMOD1_3A (PMOD1 PIN HEADER) |
>> + * | SCIF1_CTS# (pin1) (pin7) PMOD1_GPIO10 |
>> + * | SCIF1_TXD (pin2) (pin8) PMOD1_GPIO11 |
>> + * | SCIF1_RXD (pin3) (pin9) PMOD1_GPIO12 |
>> + * | SCIF1_RTS# (pin4) (pin10) PMOD1_GPIO13 |
>> + * | GND (pin5) (pin11) GND |
>> + * | PWR_PMOD1 (pin6) (pin12) GND |
>> + * +--------------------------------------------+
>
> This depends not only on CONFIG_SW3 (for RXD only), but also on
> SW_OPT_MUX4 (SW_SER0_PMOD=L gates all 4 SCIF1 signals).

You're right!

> While including "rzg3s-smarc-switches.h" for (out-of-tree) overlay
> configfs is not really needed, please document the switches in the
> comments.

Sure!

> As this is included in r9a08g045s33-smarc-pmod.dtb, you
> may still want to include "rzg3s-smarc-switches.h".

OK, I'll handle it in the next version.

>
>> + *
>> + */
>> +
>> +/dts-v1/;
>> +/plugin/;
>> +
>> +#include <dt-bindings/pinctrl/rzg2l-pinctrl.h>
>> +
>> +&{/} {
>> + aliases {
>> + serial0 = "/soc/serial@1004bc00";
>
> Note that configuring aliases doesn't work in dynamic overlays
> (but we don't care in upstream).
> However, this is also wired on the Carrier board to the M2 slot when
> SW_SER0_PMOD is low. so I think it makes sense to have the alias
> unconditionally in rzg3s-smarc.dtsi instead.

OK, I'll move it there.

Thank you for your review,
Claudiu

>
>> + };
>
> Gr{oetje,eeting}s,
>
> Geert
>