Jetson/FAQ/BSP/Nano Wakeup Pin

= Environment =

Hardware

 * Jetson Nano

Software
= Use case = Set GPIO(UART1_CTS/PG03) as wake up source to trigger OS resume. = Steps = Note: All changes are in kernel device tree.
 * JetPack 4.4 (32.4.3)

Set PG03 GPIO as input

 * Make sure TEGRA_GPIO(G, 3) inside of gpio@6000d000.default.gpio-input property from tegra210-porg-gpio-p3448-0002-b00.dtsi
 * Make sure TEGRA_GPIO(G, 3) outside of gpio@6000d000.default.gpio-output property from tegra210-porg-gpio-p3448-0002-b00.dtsi

Set pinmux
uart2_cts_pg3 { nvidia,pins = "uart2_cts_pg3"; nvidia,function = "rsvd2"; nvidia,pull = ; nvidia,tristate = ; nvidia,enable-input = ; };
 * Set pinmux as below in pinmux@700008d4.common.uart2_cts_pg3 node from tegra210-porg-pinmux-p3448-0002-b00.dtsi
 * Make sure uart2_cts_pg3 node NOT inside of pinmux@700008d4.unused_lowpower node from tegra210-porg-pinmux-p3448-0002-b00.dtsi.

Create GPIO key to trigger wake up signal
Add following node to tegra210-p3448-0002-p3449-0000-b00.dts. gpio-keys { wakeup_key { label = "WakeupKey"; gpios = <&gpio TEGRA_GPIO(G, 3) GPIO_ACTIVE_LOW>; linux,code = ; gpio-key,wakeup; debounce-interval = <30>; nvidia,pmc-wakeup = <&tegra_pmc PMC_WAKE_TYPE_GPIO 6 PMC_TRIGGER_TYPE_NONE>; }; }; Pay attention of nvidia,pmc-wakeup property, the number 6 means wake up ID of Nano. You can find this ID from Column Y of Nano_Module_Pinmux_Config file which comes from Jetson Download Center.

= Verification = GPIO PG03 is the Num 36 pin of [J41] 40-pin Exp Header on carrier board. Debug UART RX/TX can provide high voltage even OS suspend. Re-build device tree and re-flash to Nano. After boot completed, exec "sudo systemctl suspend" to suspend OS. Connect that 36 Pin and debug uart RX/TX via Dupont wire to wake up OS.