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[2a02:3100:ad73:6800::e63]) by smtp.googlemail.com with ESMTPSA id a640c23a62f3a-ac7196dd46asm364497866b.160.2025.03.29.11.59.14 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 29 Mar 2025 11:59:16 -0700 (PDT) From: Martin Blumenstingl To: linux-amlogic@lists.infradead.org Cc: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, jbrunet@baylibre.com, khilman@baylibre.com, neil.armstrong@linaro.org, christianshewitt@gmail.com, Martin Blumenstingl Subject: [PATCH 1/7] ARM: dts: amlogic: meson8: enable UART RX and TX pull up by default Date: Sat, 29 Mar 2025 19:58:49 +0100 Message-ID: <20250329185855.854186-2-martin.blumenstingl@googlemail.com> X-Mailer: git-send-email 2.49.0 In-Reply-To: <20250329185855.854186-1-martin.blumenstingl@googlemail.com> References: <20250329185855.854186-1-martin.blumenstingl@googlemail.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" Some boards have noise on the UART RX line when the UART pins are not connected to another device (such as an USB UART adapter). This can be addressed by using a pull up resistor. Not all boards may provide such a pull up resistor on the PCB so enable the SoC's pull-up on the UART RX and TX pads by default. This matches the default (from u-boot or SoC hardware) state for the pinmux configuration on these pads. Signed-off-by: Martin Blumenstingl Reviewed-by: Neil Armstrong --- arch/arm/boot/dts/amlogic/meson8.dtsi | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/arm/boot/dts/amlogic/meson8.dtsi b/arch/arm/boot/dts/amlo= gic/meson8.dtsi index 847f7b1f1e96..7fe0c7d3ee6e 100644 --- a/arch/arm/boot/dts/amlogic/meson8.dtsi +++ b/arch/arm/boot/dts/amlogic/meson8.dtsi @@ -398,7 +398,7 @@ uart_ao_a_pins: uart_ao_a { mux { groups =3D "uart_tx_ao_a", "uart_rx_ao_a"; function =3D "uart_ao"; - bias-disable; + bias-pull-up; }; }; =20 @@ -567,7 +567,7 @@ mux { groups =3D "uart_tx_a1", "uart_rx_a1"; function =3D "uart_a"; - bias-disable; + bias-pull-up; }; }; =20 --=20 2.49.0 From nobody Fri Dec 19 18:31:43 2025 Received: from mail-ej1-f42.google.com (mail-ej1-f42.google.com [209.85.218.42]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 80AFB1DF75B; Sat, 29 Mar 2025 18:59:23 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; 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[2a02:3100:ad73:6800::e63]) by smtp.googlemail.com with ESMTPSA id a640c23a62f3a-ac7196dd46asm364497866b.160.2025.03.29.11.59.17 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 29 Mar 2025 11:59:20 -0700 (PDT) From: Martin Blumenstingl To: linux-amlogic@lists.infradead.org Cc: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, jbrunet@baylibre.com, khilman@baylibre.com, neil.armstrong@linaro.org, christianshewitt@gmail.com, Martin Blumenstingl Subject: [PATCH 2/7] ARM: dts: amlogic: meson8b: enable UART RX and TX pull up by default Date: Sat, 29 Mar 2025 19:58:50 +0100 Message-ID: <20250329185855.854186-3-martin.blumenstingl@googlemail.com> X-Mailer: git-send-email 2.49.0 In-Reply-To: <20250329185855.854186-1-martin.blumenstingl@googlemail.com> References: <20250329185855.854186-1-martin.blumenstingl@googlemail.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" Some boards have noise on the UART RX line when the UART pins are not connected to another device (such as an USB UART adapter). This can be addressed by using a pull up resistor. Not all boards may provide such a pull up resistor on the PCB so enable the SoC's pull-up on the UART RX and TX pads by default. This matches the default (from u-boot or SoC hardware) state for the pinmux configuration on these pads. Signed-off-by: Martin Blumenstingl Reviewed-by: Neil Armstrong --- arch/arm/boot/dts/amlogic/meson8b.dtsi | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/arm/boot/dts/amlogic/meson8b.dtsi b/arch/arm/boot/dts/aml= ogic/meson8b.dtsi index 0876611ce26a..faf09f77c605 100644 --- a/arch/arm/boot/dts/amlogic/meson8b.dtsi +++ b/arch/arm/boot/dts/amlogic/meson8b.dtsi @@ -368,7 +368,7 @@ uart_ao_a_pins: uart_ao_a { mux { groups =3D "uart_tx_ao_a", "uart_rx_ao_a"; function =3D "uart_ao"; - bias-disable; + bias-pull-up; }; }; =20 @@ -521,7 +521,7 @@ mux { groups =3D "uart_tx_b0", "uart_rx_b0"; function =3D "uart_b"; - bias-disable; + bias-pull-up; }; }; =20 --=20 2.49.0 From nobody Fri Dec 19 18:31:43 2025 Received: from mail-ej1-f46.google.com (mail-ej1-f46.google.com [209.85.218.46]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 6A2B11DED4B; Sat, 29 Mar 2025 18:59:25 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; 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[2a02:3100:ad73:6800::e63]) by smtp.googlemail.com with ESMTPSA id a640c23a62f3a-ac7196dd46asm364497866b.160.2025.03.29.11.59.21 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 29 Mar 2025 11:59:22 -0700 (PDT) From: Martin Blumenstingl To: linux-amlogic@lists.infradead.org Cc: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, jbrunet@baylibre.com, khilman@baylibre.com, neil.armstrong@linaro.org, christianshewitt@gmail.com, Martin Blumenstingl Subject: [PATCH 3/7] arm64: dts: amlogic: gxbb: enable UART RX and TX pull up by default Date: Sat, 29 Mar 2025 19:58:51 +0100 Message-ID: <20250329185855.854186-4-martin.blumenstingl@googlemail.com> X-Mailer: git-send-email 2.49.0 In-Reply-To: <20250329185855.854186-1-martin.blumenstingl@googlemail.com> References: <20250329185855.854186-1-martin.blumenstingl@googlemail.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" Some boards have noise on the UART RX line when the UART pins are not connected to another device (such as an USB UART adapter). This can be addressed by using a pull up resistor. Not all boards may provide such a pull up resistor on the PCB so enable the SoC's pull-up on the UART RX and TX pads by default. This matches the default (from u-boot or SoC hardware) state for the pinmux configuration on these pads. Signed-off-by: Martin Blumenstingl Reviewed-by: Neil Armstrong --- arch/arm64/boot/dts/amlogic/meson-gxbb.dtsi | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff --git a/arch/arm64/boot/dts/amlogic/meson-gxbb.dtsi b/arch/arm64/boot/= dts/amlogic/meson-gxbb.dtsi index 8ebce7114a60..c4a9f855e5de 100644 --- a/arch/arm64/boot/dts/amlogic/meson-gxbb.dtsi +++ b/arch/arm64/boot/dts/amlogic/meson-gxbb.dtsi @@ -105,7 +105,7 @@ uart_ao_a_pins: uart_ao_a { mux { groups =3D "uart_tx_ao_a", "uart_rx_ao_a"; function =3D "uart_ao"; - bias-disable; + bias-pull-up; }; }; =20 @@ -122,7 +122,7 @@ uart_ao_b_pins: uart_ao_b { mux { groups =3D "uart_tx_ao_b", "uart_rx_ao_b"; function =3D "uart_ao_b"; - bias-disable; + bias-pull-up; }; }; =20 @@ -520,7 +520,7 @@ mux { groups =3D "uart_tx_a", "uart_rx_a"; function =3D "uart_a"; - bias-disable; + bias-pull-up; }; }; =20 @@ -538,7 +538,7 @@ mux { groups =3D "uart_tx_b", "uart_rx_b"; function =3D "uart_b"; - bias-disable; + bias-pull-up; }; }; 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[2a02:3100:ad73:6800::e63]) by smtp.googlemail.com with ESMTPSA id a640c23a62f3a-ac7196dd46asm364497866b.160.2025.03.29.11.59.23 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 29 Mar 2025 11:59:24 -0700 (PDT) From: Martin Blumenstingl To: linux-amlogic@lists.infradead.org Cc: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, jbrunet@baylibre.com, khilman@baylibre.com, neil.armstrong@linaro.org, christianshewitt@gmail.com, Martin Blumenstingl Subject: [PATCH 4/7] arm64: dts: amlogic: gxl: enable UART RX and TX pull up by default Date: Sat, 29 Mar 2025 19:58:52 +0100 Message-ID: <20250329185855.854186-5-martin.blumenstingl@googlemail.com> X-Mailer: git-send-email 2.49.0 In-Reply-To: <20250329185855.854186-1-martin.blumenstingl@googlemail.com> References: <20250329185855.854186-1-martin.blumenstingl@googlemail.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" Some boards have noise on the UART RX line when the UART pins are not connected to another device (such as an USB UART adapter). This can be addressed by using a pull up resistor. Not all boards may provide such a pull up resistor on the PCB so enable the SoC's pull-up on the UART RX and TX pads by default. This matches the default (from u-boot or SoC hardware) state for the pinmux configuration on these pads. Signed-off-by: Martin Blumenstingl Reviewed-by: Neil Armstrong --- arch/arm64/boot/dts/amlogic/meson-gxl.dtsi | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) diff --git a/arch/arm64/boot/dts/amlogic/meson-gxl.dtsi b/arch/arm64/boot/d= ts/amlogic/meson-gxl.dtsi index 2dc2fdaecf9f..460c46cfad6a 100644 --- a/arch/arm64/boot/dts/amlogic/meson-gxl.dtsi +++ b/arch/arm64/boot/dts/amlogic/meson-gxl.dtsi @@ -163,7 +163,7 @@ uart_ao_a_pins: uart_ao_a { mux { groups =3D "uart_tx_ao_a", "uart_rx_ao_a"; function =3D "uart_ao"; - bias-disable; + bias-pull-up; }; }; =20 @@ -180,7 +180,7 @@ uart_ao_b_pins: uart_ao_b { mux { groups =3D "uart_tx_ao_b", "uart_rx_ao_b"; function =3D "uart_ao_b"; - bias-disable; + bias-pull-up; }; }; =20 @@ -188,7 +188,7 @@ uart_ao_b_0_1_pins: uart_ao_b_0_1 { mux { groups =3D "uart_tx_ao_b_0", "uart_rx_ao_b_1"; function =3D "uart_ao_b"; - bias-disable; + bias-pull-up; }; }; =20 @@ -522,7 +522,7 @@ mux { groups =3D "uart_tx_a", "uart_rx_a"; function =3D "uart_a"; 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[2a02:3100:ad73:6800::e63]) by smtp.googlemail.com with ESMTPSA id a640c23a62f3a-ac7196dd46asm364497866b.160.2025.03.29.11.59.26 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 29 Mar 2025 11:59:27 -0700 (PDT) From: Martin Blumenstingl To: linux-amlogic@lists.infradead.org Cc: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, jbrunet@baylibre.com, khilman@baylibre.com, neil.armstrong@linaro.org, christianshewitt@gmail.com, Martin Blumenstingl Subject: [PATCH 5/7] arm64: dts: amlogic: g12: enable UART RX and TX pull up by default Date: Sat, 29 Mar 2025 19:58:53 +0100 Message-ID: <20250329185855.854186-6-martin.blumenstingl@googlemail.com> X-Mailer: git-send-email 2.49.0 In-Reply-To: <20250329185855.854186-1-martin.blumenstingl@googlemail.com> References: <20250329185855.854186-1-martin.blumenstingl@googlemail.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" Some boards have noise on the UART RX line when the UART pins are not connected to another device (such as an USB UART adapter). This can be addressed by using a pull up resistor. Not all boards may provide such a pull up resistor on the PCB so enable the SoC's pull-up on the UART RX and TX pads by default. This matches the default (from u-boot or SoC hardware) state for the pinmux configuration on these pads. Signed-off-by: Martin Blumenstingl Reviewed-by: Neil Armstrong --- arch/arm64/boot/dts/amlogic/meson-g12-common.dtsi | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff --git a/arch/arm64/boot/dts/amlogic/meson-g12-common.dtsi b/arch/arm64= /boot/dts/amlogic/meson-g12-common.dtsi index ab2b3f15ef19..12e8daaa1c9b 100644 --- a/arch/arm64/boot/dts/amlogic/meson-g12-common.dtsi +++ b/arch/arm64/boot/dts/amlogic/meson-g12-common.dtsi @@ -1503,7 +1503,7 @@ mux { groups =3D "uart_a_tx", "uart_a_rx"; function =3D "uart_a"; - bias-disable; + bias-pull-up; }; }; =20 @@ -1521,7 +1521,7 @@ mux { groups =3D "uart_b_tx", "uart_b_rx"; function =3D "uart_b"; - bias-disable; + bias-pull-up; }; }; =20 @@ -1918,7 +1918,7 @@ mux { groups =3D "uart_ao_a_tx", "uart_ao_a_rx"; function =3D "uart_ao_a"; - bias-disable; + bias-pull-up; }; }; =20 @@ -1936,7 +1936,7 @@ mux { groups =3D "uart_ao_b_tx_2", "uart_ao_b_rx_3"; function =3D "uart_ao_b"; - bias-disable; + bias-pull-up; }; }; =20 @@ -1945,7 +1945,7 @@ mux { groups =3D "uart_ao_b_tx_8", "uart_ao_b_rx_9"; 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[2a02:3100:ad73:6800::e63]) by smtp.googlemail.com with ESMTPSA id a640c23a62f3a-ac7196dd46asm364497866b.160.2025.03.29.11.59.28 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 29 Mar 2025 11:59:28 -0700 (PDT) From: Martin Blumenstingl To: linux-amlogic@lists.infradead.org Cc: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, jbrunet@baylibre.com, khilman@baylibre.com, neil.armstrong@linaro.org, christianshewitt@gmail.com, Martin Blumenstingl Subject: [PATCH 6/7] arm64: dts: amlogic: axg: enable UART RX and TX pull up by default Date: Sat, 29 Mar 2025 19:58:54 +0100 Message-ID: <20250329185855.854186-7-martin.blumenstingl@googlemail.com> X-Mailer: git-send-email 2.49.0 In-Reply-To: <20250329185855.854186-1-martin.blumenstingl@googlemail.com> References: <20250329185855.854186-1-martin.blumenstingl@googlemail.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" Some boards have noise on the UART RX line when the UART pins are not connected to another device (such as an USB UART adapter). This can be addressed by using a pull up resistor. Not all boards may provide such a pull up resistor on the PCB so enable the SoC's pull-up on the UART RX and TX pads by default. This matches the default (from u-boot or SoC hardware) state for the pinmux configuration on these pads. Signed-off-by: Martin Blumenstingl Reviewed-by: Neil Armstrong --- arch/arm64/boot/dts/amlogic/meson-axg.dtsi | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) diff --git a/arch/arm64/boot/dts/amlogic/meson-axg.dtsi b/arch/arm64/boot/d= ts/amlogic/meson-axg.dtsi index a6924d246bb1..2df143aa77ce 100644 --- a/arch/arm64/boot/dts/amlogic/meson-axg.dtsi +++ b/arch/arm64/boot/dts/amlogic/meson-axg.dtsi @@ -1164,7 +1164,7 @@ mux { groups =3D "uart_tx_a", "uart_rx_a"; function =3D "uart_a"; - bias-disable; + bias-pull-up; }; }; =20 @@ -1182,7 +1182,7 @@ mux { groups =3D "uart_tx_b_x", "uart_rx_b_x"; function =3D "uart_b"; - bias-disable; + bias-pull-up; }; }; =20 @@ -1200,7 +1200,7 @@ mux { groups =3D "uart_tx_b_z", "uart_rx_b_z"; function =3D "uart_b"; - bias-disable; + bias-pull-up; }; }; =20 @@ -1218,7 +1218,7 @@ mux { groups =3D "uart_ao_tx_b_z", "uart_ao_rx_b_z"; function =3D "uart_ao_b_z"; - bias-disable; + bias-pull-up; }; }; =20 @@ -1654,7 +1654,7 @@ mux { groups =3D "uart_ao_tx_a", "uart_ao_rx_a"; 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[2a02:3100:ad73:6800::e63]) by smtp.googlemail.com with ESMTPSA id a640c23a62f3a-ac7196dd46asm364497866b.160.2025.03.29.11.59.30 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 29 Mar 2025 11:59:31 -0700 (PDT) From: Martin Blumenstingl To: linux-amlogic@lists.infradead.org Cc: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, jbrunet@baylibre.com, khilman@baylibre.com, neil.armstrong@linaro.org, christianshewitt@gmail.com, Martin Blumenstingl Subject: [PATCH 7/7] arm64: dts: amlogic: a1: enable UART RX and TX pull up by default Date: Sat, 29 Mar 2025 19:58:55 +0100 Message-ID: <20250329185855.854186-8-martin.blumenstingl@googlemail.com> X-Mailer: git-send-email 2.49.0 In-Reply-To: <20250329185855.854186-1-martin.blumenstingl@googlemail.com> References: <20250329185855.854186-1-martin.blumenstingl@googlemail.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" Some boards have noise on the UART RX line when the UART pins are not connected to another device (such as an USB UART adapter). This can be addressed by using a pull up resistor. Not all boards may provide such a pull up resistor on the PCB so enable the SoC's pull-up on the UART RX and TX pads by default. This matches the default (from u-boot or SoC hardware) state for the pinmux configuration on these pads. Signed-off-by: Martin Blumenstingl Reviewed-by: Neil Armstrong --- arch/arm64/boot/dts/amlogic/meson-a1.dtsi | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/arm64/boot/dts/amlogic/meson-a1.dtsi b/arch/arm64/boot/dt= s/amlogic/meson-a1.dtsi index 1eba0afb3fd9..f7f25a10f409 100644 --- a/arch/arm64/boot/dts/amlogic/meson-a1.dtsi +++ b/arch/arm64/boot/dts/amlogic/meson-a1.dtsi @@ -233,6 +233,7 @@ mux { groups =3D "uart_a_tx", "uart_a_rx"; function =3D "uart_a"; + bias-pull-up; }; }; =20 --=20 2.49.0