Re: [PATCH v1 5/6] arm64: dts: meson: a1: introduce UART_AO mux definitions

From: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
To: Dmitry Rokosov <ddrokosov@sberdevices.ru>
Cc: neil.armstrong@linaro.org, jbrunet@baylibre.com,
	mturquette@baylibre.com, sboyd@kernel.org, robh+dt@kernel.org,
	krzysztof.kozlowski+dt@linaro.org, khilman@baylibre.com,
	conor+dt@kernel.org, kernel@sberdevices.ru,
	sdfw_system_team@sberdevices.ru, rockosov@gmail.com,
	linux-amlogic@lists.infradead.org, linux-clk@vger.kernel.org,
	devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org,
	Oleg Lyovin <ovlevin@sberdevices.ru>
Subject: Re: [PATCH v1 5/6] arm64: dts: meson: a1: introduce UART_AO mux definitions
Date: Sun, 25 Jun 2023 23:07:51 +0200	[thread overview]
Message-ID: <CAFBinCD-5RD_iszZZRg58XqTHDEHnipJkf2aAex8MdUyh=bVCw@mail.gmail.com> (raw)
In-Reply-To: <20230607201641.20982-6-ddrokosov@sberdevices.ru>

On Wed, Jun 7, 2023 at 10:16 PM Dmitry Rokosov <ddrokosov@sberdevices.ru> wrote:
>
> From: Oleg Lyovin <ovlevin@sberdevices.ru>
>
> The Amlogic A1 has a UART_AO port, which can be used, for example, for
> BT HCI H4 connection.
>
> This patch adds mux definitions for it.
In the past we've only taken the pinctrl definitions if we have a
board that uses them.
Neil, do we still have the same policy in place? If so this patch
should be sent with the series that adds support for your A1 board.

> Signed-off-by: Oleg Lyovin <ovlevin@sberdevices.ru>
> Signed-off-by: Dmitry Rokosov <ddrokosov@sberdevices.ru>
> ---
>  arch/arm64/boot/dts/amlogic/meson-a1.dtsi | 16 ++++++++++++++++
>  1 file changed, 16 insertions(+)
>
> diff --git a/arch/arm64/boot/dts/amlogic/meson-a1.dtsi b/arch/arm64/boot/dts/amlogic/meson-a1.dtsi
> index 0efd922ca7e1..3eb6aa9c00e0 100644
> --- a/arch/arm64/boot/dts/amlogic/meson-a1.dtsi
> +++ b/arch/arm64/boot/dts/amlogic/meson-a1.dtsi
> @@ -118,6 +118,22 @@ gpio: bank@400 {
>                                         gpio-ranges = <&periphs_pinctrl 0 0 62>;
>                                 };
>
> +                               uart_a_pins: uart_a {
Only our newer .dtsi (e.g. meson-g12-common.dtsi) are following the
pattern where node names should use dashes instead of underscores.
So please use: uart_a_pins: uart-a { ...

[...]
> +                               uart_a_cts_rts_pins: uart_a_cts_rts {
similar to the comment from above:
uart_a_cts_rts_pins: uart-a-cts-rts { ...

> +                                       mux {
> +                                               groups = "uart_a_cts",
> +                                                        "uart_a_rts";
> +                                               function = "uart_a";
> +                                               bias-pull-down;
Out of curiosity: is this pull down needed on all boards or just specific ones?
It seems like all other SoCs use bias-disable for the RTS/CTS pins.


Best regards,
Martin