linux-kernel - Re: [PATCH 11/14] arm64: renesas: rzg3s-smarc-som: Invert the logic for SW_SD2

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Date:   Wed, 6 Dec 2023 11:33:17 +0100
From:   Geert Uytterhoeven <geert@...ux-m68k.org>
To:     Claudiu <claudiu.beznea@...on.dev>
Cc:     s.shtylyov@....ru, davem@...emloft.net, edumazet@...gle.com,
        kuba@...nel.org, pabeni@...hat.com, robh+dt@...nel.org,
        krzysztof.kozlowski+dt@...aro.org, conor+dt@...nel.org,
        linux@...linux.org.uk, geert+renesas@...der.be,
        magnus.damm@...il.com, mturquette@...libre.com, sboyd@...nel.org,
        linus.walleij@...aro.org, p.zabel@...gutronix.de, arnd@...db.de,
        m.szyprowski@...sung.com, alexandre.torgue@...s.st.com, afd@...com,
        broonie@...nel.org, alexander.stein@...tq-group.com,
        eugen.hristev@...labora.com, sergei.shtylyov@...il.com,
        prabhakar.mahadev-lad.rj@...renesas.com,
        biju.das.jz@...renesas.com, linux-renesas-soc@...r.kernel.org,
        netdev@...r.kernel.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        linux-clk@...r.kernel.org, linux-gpio@...r.kernel.org,
        Claudiu Beznea <claudiu.beznea.uj@...renesas.com>
Subject: Re: [PATCH 11/14] arm64: renesas: rzg3s-smarc-som: Invert the logic
 for SW_SD2_EN macro

Hi Claudiu,

On Mon, Nov 20, 2023 at 8:03 AM Claudiu <claudiu.beznea@...on.dev> wrote:
> From: Claudiu Beznea <claudiu.beznea.uj@...renesas.com>
>
> The intention of SW_SD2_EN macro was to reflect the state of SW_CONFIG3
> switch available on RZ/G3S Smarc Module. According to documentation SD2
> is enabled when switch is in OFF state. For this, changed the logic of
> marco to map value 0 to switch's OFF state and value 1 to switch's ON
> state. Along with this update the description for each state for better
> understanding.
>
> The value of SW_SD2_EN macro was not changed in file because, according to
> documentation, the default state for this switch is ON.
>
> Fixes: adb4f0c5699c ("arm64: dts: renesas: Add initial support for RZ/G3S SMARC SoM")
> Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@...renesas.com>

Thanks for your patch!

> --- a/arch/arm64/boot/dts/renesas/rzg3s-smarc-som.dtsi
> +++ b/arch/arm64/boot/dts/renesas/rzg3s-smarc-som.dtsi
> @@ -14,8 +14,8 @@
>   *     0 - SD0 is connected to eMMC
>   *     1 - SD0 is connected to uSD0 card
>   * @SW_SD2_EN:
> - *     0 - SCIF1, SSI0, IRQ0, IRQ1 connected to SoC
> - *     1 - SD2 is connected to SoC
> + *     0 - (switch OFF) SD2 is connected to SoC
> + *     1 - (switch ON)  SCIF1, SSI0, IRQ0, IRQ1 connected to SoC

I think this is still confusing: SW_SD2_EN refers to an active-low signal
(SW_SD2_EN#) in the schematics.

Before, SW_SD2_EN used assertion-logic (1 is enabled), and didn't
match the physical signal level.
After your patch, SW_SD2_EN matches the active-low physical level, but
this is not reflected in the name...

>   */
>  #define SW_SD0_DEV_SEL 1
>  #define SW_SD2_EN      1
> @@ -25,7 +25,7 @@ / {
>
>         aliases {
>                 mmc0 = &sdhi0;
> -#if SW_SD2_EN
> +#if !SW_SD2_EN

... so this condition looks really weird.

>                 mmc2 = &sdhi2;
>  #endif
>         };
> @@ -116,7 +116,7 @@ &sdhi0 {
>  };
>  #endif
>
> -#if SW_SD2_EN
> +#if !SW_SD2_EN
>  &sdhi2 {
>         pinctrl-0 = <&sdhi2_pins>;
>         pinctrl-names = "default";

So I think SW_SD2_EN should be renamed to SW_SD2_EN_N.

Cfr. SW_ET0_EN_N on RZ/G2UL:

arch/arm64/boot/dts/renesas/r9a07g043u11-smarc.dts- * DIP-Switch SW1 setting
arch/arm64/boot/dts/renesas/r9a07g043u11-smarc.dts- * 1 : High; 0: Low
arch/arm64/boot/dts/renesas/r9a07g043u11-smarc.dts- * SW1-2 :
SW_SD0_DEV_SEL    (0: uSD; 1: eMMC)
arch/arm64/boot/dts/renesas/r9a07g043u11-smarc.dts- * SW1-3 :
SW_ET0_EN_N               (0: ETHER0; 1: CAN0, CAN1, SSI1, RSPI1)
arch/arm64/boot/dts/renesas/r9a07g043u11-smarc.dts- * Please change
below macros according to SW1 setting on the SoM

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@...ux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds