linux-kernel - [PATCH v3 2/5] arm64: dts: ti: k3-am62x-sk-common: Enable Main UART wakeup

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Message-ID: <20260106-b4-uart-daisy-chain-dts-v3-2-398a66258f2c@ti.com>
Date: Tue, 6 Jan 2026 18:42:19 -0600
From: Kendall Willis <k-willis@...com>
To: Nishanth Menon <nm@...com>, Vignesh Raghavendra <vigneshr@...com>, "Tero
 Kristo" <kristo@...nel.org>, Rob Herring <robh@...nel.org>, "Krzysztof
 Kozlowski" <krzk+dt@...nel.org>, Conor Dooley <conor+dt@...nel.org>,
	<d-gole@...com>, <msp@...libre.com>
CC: <vishalm@...com>, <sebin.francis@...com>, <khilman@...libre.com>,
	<a-kaur@...com>, <s-kochidanadu@...com>,
	<linux-arm-kernel@...ts.infradead.org>, <devicetree@...r.kernel.org>,
	<linux-kernel@...r.kernel.org>, Kendall Willis <k-willis@...com>
Subject: [PATCH v3 2/5] arm64: dts: ti: k3-am62x-sk-common: Enable Main
 UART wakeup

The Main UART can resume from suspend to RAM states when PIN_WKUP_EN
is enabled. Add the necessary pins needed to wakeup the system. Add the
system idle states that the Main UART can wakeup the system from.

The UART driver uses the "default" pinctrl state when the system is
active. In the suspend hook, if the UART is wakeup enabled, the "wakeup"
pinctrl state is selected by the UART driver in order to allow wakeup.
Upon resume, the default pinctrl state is selected again.

Reviewed-by: Markus Schneider-Pargmann <msp@...libre.com>
Reviewed-by: Dhruva Gole <d-gole@...com>
Signed-off-by: Kendall Willis <k-willis@...com>
---
 arch/arm64/boot/dts/ti/k3-am62x-sk-common.dtsi | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/boot/dts/ti/k3-am62x-sk-common.dtsi b/arch/arm64/boot/dts/ti/k3-am62x-sk-common.dtsi
index 50ed859ae06c47af38b11753d909a91485d438e5..ab9e58c2d225eb44c054d984aad8f0bed92bf7e9 100644
--- a/arch/arm64/boot/dts/ti/k3-am62x-sk-common.dtsi
+++ b/arch/arm64/boot/dts/ti/k3-am62x-sk-common.dtsi
@@ -151,6 +151,13 @@ AM62X_IOPAD(0x1cc, PIN_OUTPUT, 0) /* (E14/E11) UART0_TXD */
 		>;
 	};
 
+	main_uart0_pins_wakeup: main-uart0-wakeup-pins {
+		pinctrl-single,pins = <
+			AM62X_IOPAD(0x1c8, PIN_INPUT | PIN_WKUP_EN, 0) /* (D14/A13) UART0_RXD */
+			AM62X_IOPAD(0x1cc, PIN_OUTPUT, 0) /* (E14/E11) UART0_TXD */
+		>;
+	};
+
 	main_uart1_pins_default: main-uart1-default-pins {
 		bootph-pre-ram;
 		pinctrl-single,pins = <
@@ -322,8 +329,12 @@ &wkup_uart0 {
 &main_uart0 {
 	bootph-all;
 	status = "okay";
-	pinctrl-names = "default";
+	pinctrl-names = "default", "wakeup";
 	pinctrl-0 = <&main_uart0_pins_default>;
+	pinctrl-1 = <&main_uart0_pins_wakeup>;
+	wakeup-source = <&system_deep_sleep>,
+			<&system_mcu_only>,
+			<&system_standby>;
 };
 
 &main_uart1 {

-- 
2.34.1