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[83.173.201.248]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-48722cb5845sm34024185e9.15.2026.03.26.07.37.34 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 26 Mar 2026 07:37:35 -0700 (PDT) From: Franz Schnyder To: Rob Herring , Krzysztof Kozlowski , Conor Dooley , Frank Li , Sascha Hauer , Pengutronix Kernel Team , Fabio Estevam Cc: Franz Schnyder , devicetree@vger.kernel.org, imx@lists.linux.dev, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Francesco Dolcini Subject: [PATCH v2 3/3] arm64: dts: freescale: imx95-toradex-smarc: Use gpio-hog for WIFI_UART_EN Date: Thu, 26 Mar 2026 15:37:06 +0100 Message-ID: <20260326143711.143462-4-fra.schnyder@gmail.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260326143711.143462-1-fra.schnyder@gmail.com> References: <20260326143711.143462-1-fra.schnyder@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Franz Schnyder On the Toradex SMARC iMX95, the WiFi UART signals are shared with the JTAG. The WIFI_UART_EN signal is used to select between these two functions. A GPIO hog is used to select the UART function by default. This DT file is going to be used by both Linux and the boot firmware, and the boot firmware will configure the GPIO hog way before the Linux kernel is booted, therefore there is no actual race condition between the Linux kernel BT UART driver and GPIO hog probe. Configure WIFI_UART_EN as a gpio-hog driven high. Signed-off-by: Franz Schnyder --- v2: Remove unused label for wifi-uart-en-hog node Add explanation to clarify the safe usage of the GPIO hog --- arch/arm64/boot/dts/freescale/imx95-toradex-smarc.dtsi | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/arch/arm64/boot/dts/freescale/imx95-toradex-smarc.dtsi b/arch/= arm64/boot/dts/freescale/imx95-toradex-smarc.dtsi index a90edefc5197..8eef26eb0f87 100644 --- a/arch/arm64/boot/dts/freescale/imx95-toradex-smarc.dtsi +++ b/arch/arm64/boot/dts/freescale/imx95-toradex-smarc.dtsi @@ -451,6 +451,13 @@ som_gpio_expander_1: gpio@21 { "", "", "SMARC_SDIO_WP"; + + wifi-uart-en-hog { + gpio-hog; + gpios =3D <12 GPIO_ACTIVE_HIGH>; + line-name =3D "WIFI_UART_EN"; + output-high; + }; }; =20 embedded-controller@28 { --=20 2.43.0