linux-kernel - Re: [PATCH 07/10] arm64: dts: imx8mp-skov: configure uart1 for RS485

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <Z2RbINlmO9UL+MPH@lizhi-Precision-Tower-5810>
Date: Thu, 19 Dec 2024 12:42:56 -0500
From: Frank Li <Frank.li@....com>
To: Ahmad Fatoum <a.fatoum@...gutronix.de>
Cc: Rob Herring <robh@...nel.org>, Krzysztof Kozlowski <krzk+dt@...nel.org>,
	Conor Dooley <conor+dt@...nel.org>, Shawn Guo <shawnguo@...nel.org>,
	Sascha Hauer <s.hauer@...gutronix.de>,
	Pengutronix Kernel Team <kernel@...gutronix.de>,
	Fabio Estevam <festevam@...il.com>,
	Oleksij Rempel <o.rempel@...gutronix.de>,
	devicetree@...r.kernel.org, imx@...ts.linux.dev,
	linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 07/10] arm64: dts: imx8mp-skov: configure uart1 for RS485

On Thu, Dec 19, 2024 at 08:25:31AM +0100, Ahmad Fatoum wrote:
> uart1 TX, RX and RTS signals go off the base board and to a RS485
> transceiver. Describe this in the device tree.

Look like it is not related what your did in this patch.

Add uart-has-rtscts in uart1 to ... (because ....)

Frank
>
> Signed-off-by: Ahmad Fatoum <a.fatoum@...gutronix.de>
> ---
>  arch/arm64/boot/dts/freescale/imx8mp-skov-reva.dtsi | 9 +++++++++
>  1 file changed, 9 insertions(+)
>
> diff --git a/arch/arm64/boot/dts/freescale/imx8mp-skov-reva.dtsi b/arch/arm64/boot/dts/freescale/imx8mp-skov-reva.dtsi
> index 7ae686d37dda..bce23d62cd27 100644
> --- a/arch/arm64/boot/dts/freescale/imx8mp-skov-reva.dtsi
> +++ b/arch/arm64/boot/dts/freescale/imx8mp-skov-reva.dtsi
> @@ -404,6 +404,13 @@ &uart1 {
>  	pinctrl-names = "default";
>  	pinctrl-0 = <&pinctrl_uart1>;
>  	status = "okay";
> +	/*
> +	 * While there is no CTS line, the property "uart-has-rtscts" is still
> +	 * the right thing to do to enable the UART to do RS485. In RS485-Mode
> +	 * CTS isn't used anyhow and there is no dedicated property
> +	 * "uart-has-rts-but-no-cts".
> +	 */
> +	uart-has-rtscts;
>  };
>
>  &uart2 {
> @@ -618,6 +625,8 @@ pinctrl_uart1: uart1grp {
>  			MX8MP_IOMUXC_UART1_RXD__UART1_DCE_RX			0x140
>  			MX8MP_IOMUXC_UART1_TXD__UART1_DCE_TX			0x140
>  			MX8MP_IOMUXC_UART3_RXD__UART1_DTE_RTS			0x140
> +			/* CTS pin is not connected, but needed as workaround */

what' means here! what's problem to be workaround?

> +			MX8MP_IOMUXC_UART3_TXD__UART1_DTE_CTS			0x140
>  		>;
>  	};
>
>
> --
> 2.39.5
>