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AM62L LPM: Add new wakeup sources #537

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d0935ea
feat(pm_wakeup_sources): Add WKUP GPIO wakeup source for AM62L
kwillis01 Nov 24, 2025
8524afd
feat(pm_wakeup_sources): Add Main GPIO wakeup source for AM62L
kwillis01 Nov 25, 2025
be5dca5
feat(pm_wakeup_sources): Add WKUP UART wakeup source for AM62L
kwillis01 Nov 24, 2025
6141849
style(pm_wakeup_sources): Reword Main I/O Daisy Chain section
kwillis01 Nov 25, 2025
16d5ed8
chore(owners): Update Power Management component owners
kwillis01 Nov 25, 2025
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1 change: 1 addition & 0 deletions .github/component-owners.yml
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Original file line number Diff line number Diff line change
Expand Up @@ -88,6 +88,7 @@ components:
source/linux/Foundational_Components/Power_Management:
- DhruvaG2000
- vishalmti
- kwillis01

source/linux/Foundational_Components/Graphics:
- Antonios-C
Expand Down
291 changes: 211 additions & 80 deletions source/linux/Foundational_Components/Power_Management/pm_wakeup_sources.rst
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Expand Up @@ -53,17 +53,21 @@

.. ifconfig:: CONFIG_part_variant in ('AM62LX')

+----------------------------------+------------+----------------+
| Wakeup Source | Deep Sleep | RTC Only + DDR |
+==================================+============+================+
| Real-Time Clock (RTC) | Yes | Yes |
+----------------------------------+------------+----------------+
| Main I/O Daisy Chain (Main UART) | Yes | No |
+----------------------------------+------------+----------------+
| USB Wakeup | Yes | No |
+----------------------------------+------------+----------------+
| RTC Ext Pin | Yes | Yes |
+----------------------------------+------------+----------------+
+------------------------------------------------+------------+----------------+
| Wakeup Source | Deep Sleep | RTC Only + DDR |
+================================================+============+================+
| Real-Time Clock (RTC) | Yes | Yes |
+------------------------------------------------+------------+----------------+
| WKUP GPIO | Yes | No |

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[RedHat.Definitions] Define acronyms and abbreviations (such as 'WKUP') on first occurrence if they're likely to be unfamiliar.

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+------------------------------------------------+------------+----------------+
| Main I/O Daisy Chain (Main GPIO and Main UART) | Yes | No |
+------------------------------------------------+------------+----------------+
| WKUP UART | Yes | No |
+------------------------------------------------+------------+----------------+
| USB Wakeup | Yes | No |
+------------------------------------------------+------------+----------------+
| RTC Ext Pin | Yes | Yes |

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+------------------------------------------------+------------+----------------+

*********************
Real-Time Clock (RTC)
Expand Down Expand Up @@ -399,48 +403,138 @@
:ref:`LPM section<lpm_modes>`, wakeup from MCU_SPI0_D1 can be triggered
by grounding Pin 4 on J8 MCU Header.

*********
WKUP GPIO

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*********

.. ifconfig:: CONFIG_part_variant in ('AM62LX')

One of the most common ways to wakeup a system is by using some I/O activity.
I/O activity on the WKUP GPIOs can wakeup the system when the WKUP GPIO
controller is configured as a wakeup source. Refer to the wkup_gpio_key node
in
`k3-am62l3-evm-lpm-wkup-sources.dtso <https://git.ti.com/cgit/ti-linux-kernel/ti-linux-kernel/tree/arch/arm64/boot/dts/ti/k3-am62l3-evm-lpm-wkup-sources.dtso?h=11.02.06>`__
to use as a template to configure the desired WKUP GPIO as a wakeup capable
GPIO.

A brief guide to configuring an WKUP GPIO as wakeup:

First, add gpio-keys as a compatible string, refer to
`gpio_keys kernel documentation <https://www.kernel.org/doc/Documentation/devicetree/bindings/input/gpio-keys.txt>`__
for details.

.. code-block:: dts
compatible = "gpio-keys";
Set the desired pinctrl,

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.. code-block:: dts
pinctrl-names = "default";
pinctrl-0 = <&wake_wkupgpio0_pins_default>;
Setup the interrupt parent and interrupt as WKUP_GPIO0,

.. code-block:: dts
interrupt-parent = <&wkup_gpio0>;
interrupts = <0 IRQ_TYPE_EDGE_RISING>;
Now, under the switch node, add the following:

.. code-block:: dts
switch {
label = "WKUPGPIO";
linux,code = <143>;
gpios = <&wkup_gpio0 0 GPIO_ACTIVE_LOW>;
wakeup-source;
};
#. label: Descriptive name of the switch node. If the WKUP GPIO node is setup
correctly, the label will appear under /proc/interrupts.
#. linux,code: Keycode to emit.
#. gpios: the gpio required to be used as the gpio-key.
#. wakeup-source:
`wakeup-source <https://www.kernel.org/doc/Documentation/devicetree/bindings/power/wakeup-source.txt>`__
property describes devices which have wakeup capability.

To confirm that gpio_keys can wakeup the system from Deep Sleep, check
/proc/interrupts for the label:

.. code-block:: console
root@<machine>:~# cat /proc/interrupts | grep "WKUPGPIO"
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RST is very white-space focused. 3 spaces is the current standard. This allows code sections to clearly line up with directive

https://github.com/TexasInstruments/processor-sdk-doc/blob/master/CONTRIBUTING.md#indentation-and-whitespace

23: 0 0 GPIO 0 Edge -davinci_gpio WKUPGPIO
The WKUP GPIOs can be used to wakeup the system from Deep Sleep because WKUP
GPIOs are in a power domain that stays ON when the SoC is in Deep Sleep.
Hence, the GPIO controller is able to act as a wakeup source and send a
wakeup interrupt to the system.

WKUP GPIO wakeup can only be tested when
`k3-am62l3-evm-lpm-wkup-sources.dtso <https://git.ti.com/cgit/ti-linux-kernel/ti-linux-kernel/tree/arch/arm64/boot/dts/ti/k3-am62l3-evm-lpm-wkup-sources.dtso?h=11.02.06>`__
overlay is loaded. Refer to :ref:`How to enable DT overlays<howto_dt_overlays>` for more details.
The WKUP GPIO in the overlay is routed from the WKUP UART. With this
configuration the WKUP UART is not available as a wakeup source.

Once the system has entered Deep Sleep as shown in the
:ref:`LPM section<lpm_modes>`, wakeup from WKUP_UART0_RXD can be triggered
by entering a keypress on the WKUP UART (/dev/ttyUSB2).

.. ifconfig:: CONFIG_part_variant in ('AM62X', 'AM62AX', 'AM62PX')

Setup of WKUP GPIO is the same process of MCU GPIO. Refer to the MCU GPIO

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section on how to configure wakeup from WKUP GPIO.


********************
Main I/O Daisy Chain
********************

The main domain is powered-off when the SoC enters low power mode. This includes controllers like
Main UART, GPIO, I2C, etc. The question then arises how to wakeup the SoC from peripherals connected
to these controllers (for example main UART)? Here's where the role of I/O Daisy Chaining comes in.
At the hardware level, all the pads in an SoC have to be pinmuxed to dedicated controllers like UART or GPIO.
When the SoC enters a low power mode, the main domain is powered-off. The main

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domain includes controllers like Main UART, GPIO, I2C, etc. I/O daisy chaining

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is used in order to wakeup the SoC from peripherals that are connected to
powered-off controllers. At the hardware level, all the pads in an SoC are
pinmuxed to dedicated controllers, such as UART or GPIO.

For example, if a key press on Main UART (which is used for Linux console logs)
were to wakeup the system from Deep Sleep then simply configuring the Main UART controller as a
wakeup source wouldn't suffice. This is because the UART controller is powered off and wouldn't be able to
register any key press as such. However, at the "pad" level we are still connected, and the pads have
a specific way to be configured as wakeup sources.
For example, to wakeup the system from Deep Sleep via a key press on Main UART
(used for Linux console logs), then simply configuring the Main UART
controller as a wakeup source wouldn't work. This is because the UART
controller is powered off and wouldn't be able to register any key press as
a wakeup event. However, the UART is still connected at the "pad" level and the
pads can be configured as wakeup sources by setting a specific bit in the pad
register.

For detailed information and sequence please refer to
I/O Power Management and Daisy Chaining section in the TRM.
For detailed information and sequence please refer to I/O Power Management and
Daisy Chaining section in the TRM.

.. ifconfig:: CONFIG_part_variant in ('AM62X', 'AM62AX', 'AM62PX')

.. note::

|__PART_FAMILY_DEVICE_NAMES__| supports the ability to wakeup using pad based wake event ONLY in Deep Sleep or MCU Only Mode.
During active system usage, even if the wake_enable bit is set the system will be unresponsive to any wakeup
activity on that pad.

To demonstrate I/O daisy chain wakeup as part of |__PART_FAMILY_DEVICE_NAMES__| offering, two reference examples are provided:

#. main_uart0 is used where a key press on the Linux console can wakeup the system.
#. main_gpio is used where activity on configured GPIO pin can wakeup the system.
|__PART_FAMILY_DEVICE_NAMES__| supports the ability to wakeup using pad
based wake event ONLY in Deep Sleep or MCU Only Mode. During active
system usage, even if the wake_enable bit is set the system will be
unresponsive to any wakeup activity on that pad.

.. ifconfig:: CONFIG_part_variant in ('AM62LX')

.. note::

|__PART_FAMILY_DEVICE_NAMES__| supports the ability to wakeup using pad based wake event ONLY in Deep Sleep.
During active system usage, even if the wake_enable bit is set the system will be unresponsive to any wakeup
|__PART_FAMILY_DEVICE_NAMES__| supports the ability to wakeup using pad
based wake event ONLY in Deep Sleep. During active system usage, even if
the wake_enable bit is set the system will be unresponsive to any wakeup
activity on that pad.

To demonstrate I/O daisy chain wakeup as part of |__PART_FAMILY_DEVICE_NAMES__| offering, a reference example is provided:
To demonstrate I/O daisy chain wakeup as part of |__PART_FAMILY_DEVICE_NAMES__|
offering, two reference examples are provided:

#. main_uart0 is used where a key press on the Linux console can wakeup the system.
#. main_uart0 is used where a key press on the Linux console can wakeup the
system.
#. main_gpio is used where activity on configured GPIO pin can wakeup the
system.


Main UART
Expand Down Expand Up @@ -619,48 +713,45 @@
Main GPIO
=========

.. ifconfig:: CONFIG_part_variant in ('AM62LX')

Main GPIO wakeup is not yet supported on AM62LX.
Configuring Main GPIO as an I/O daisy chain wakeup source requires a
combination of gpio-keys with a chained IRQ in the pinctrl driver. Setting the
29th bit in the desired padconfig register, allows the pad to act as a wakeup
source by triggering a wake IRQ in Deep Sleep states.

.. ifconfig:: CONFIG_part_variant in ('AM62X', 'AM62AX', 'AM62PX')

Configuring Main GPIO as an I/O daisy chain wakeup source requires a
combination of gpio-keys with chained IRQ in the pinctrl driver. To briefly
explain, setting the 29th bit in the desired padconfig register, allows the
pad to act as a wakeup source by triggering a wake IRQ to the DM R5 in Deep
Sleep states.

The reference configuration for Main GPIO wakeup can be found under
gpio_key node in `k3-am62x-sk-lpm-wkup-sources.dtso <https://git.ti.com/cgit/ti-linux-kernel/ti-linux-kernel/tree/arch/arm64/boot/dts/ti/k3-am62x-sk-lpm-wkup-sources.dtso?h=11.01.05#n21>`__

.. code-block:: console
gpio_key {
compatible = "gpio-keys";
autorepeat;
pinctrl-names = "default";
pinctrl-0 = <&main_gpio1_pins_default>;
switch {
label = "WKGPIO";
linux,code = <KEY_WAKEUP>;
interrupts-extended = <&main_gpio1 10 IRQ_TYPE_EDGE_RISING>,
<&main_pmx0 0x1a0>;
interrupt-names = "irq", "wakeup";
};
};
gpio_key node in
`k3-am62x-sk-lpm-wkup-sources.dtso <https://git.ti.com/cgit/ti-linux-kernel/ti-linux-kernel/tree/arch/arm64/boot/dts/ti/k3-am62x-sk-lpm-wkup-sources.dtso?h=11.01.05#n21>`__
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Suggested change
`k3-am62x-sk-lpm-wkup-sources.dtso <https://git.ti.com/cgit/ti-linux-kernel/ti-linux-kernel/tree/arch/arm64/boot/dts/ti/k3-am62x-sk-lpm-wkup-sources.dtso?h=11.01.05#n21>`__
`k3-am62x-sk-lpm-wkup-sources.dtso <https://git.ti.com/cgit/ti-linux-kernel/ti-linux-kernel/tree/arch/arm64/boot/dts/ti/k3-am62x-sk-lpm-wkup-sources.dtso?h=11.02.06#n21>`__

similar to https://github.com/TexasInstruments/processor-sdk-doc/pull/537/files#diff-8f2199cf05ab6b3988cb3fcc96ced8b7635d84f112acd4b1e04e471870bb3a35R477


.. code-block:: console
gpio_key {
compatible = "gpio-keys";
autorepeat;
pinctrl-names = "default";
pinctrl-0 = <&main_gpio1_pins_default>;
switch {
label = "WKGPIO";
linux,code = <KEY_WAKEUP>;
interrupts-extended = <&main_gpio1 10 IRQ_TYPE_EDGE_RISING>,
<&main_pmx0 0x1a0>;
interrupt-names = "irq", "wakeup";
};
};
Here, we chain the IRQ to the pinctrl driver using the second
interrupts-extended entry. The wake IRQ framework in Linux works in such a
way that the second entry gets marked as a wakeup source, and then the
pinctrl driver is informed that the pad 0x1a0 in this case is to be
configured as a wakeup pad when system enters Deep Sleep.
The IRQ is chained to the pinctrl driver using the second
interrupts-extended entry. The wake IRQ framework in Linux works so that the
second entry gets marked as a wakeup source, and then the pinctrl driver is
informed that the pad, 0x1a0 in this case, is to be configured as a wakeup
pad when system enters Deep Sleep.

Main GPIO wakeup can only be tested when
`k3-am62x-sk-lpm-wkup-sources.dtso <https://git.ti.com/cgit/ti-linux-kernel/ti-linux-kernel/tree/arch/arm64/boot/dts/ti/k3-am62x-sk-lpm-wkup-sources.dtso?h=11.01.05>`__
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Suggested change
`k3-am62x-sk-lpm-wkup-sources.dtso <https://git.ti.com/cgit/ti-linux-kernel/ti-linux-kernel/tree/arch/arm64/boot/dts/ti/k3-am62x-sk-lpm-wkup-sources.dtso?h=11.01.05>`__
`k3-am62x-sk-lpm-wkup-sources.dtso <https://git.ti.com/cgit/ti-linux-kernel/ti-linux-kernel/tree/arch/arm64/boot/dts/ti/k3-am62x-sk-lpm-wkup-sources.dtso?h=11.02.06>`__

similar to https://github.com/TexasInstruments/processor-sdk-doc/pull/537/files#diff-8f2199cf05ab6b3988cb3fcc96ced8b7635d84f112acd4b1e04e471870bb3a35R477

overlay is loaded. Please refer to :ref:`How to enable DT overlays<howto_dt_overlays>` for more details.

To use main_gpio as a wakeup source, ensure gpio is a wake-irq in /proc/interrupts:
To use main_gpio as a wakeup source, ensure gpio is a wake-irq in
/proc/interrupts:

.. code-block:: console
Expand All @@ -671,32 +762,72 @@
:ref:`LPM section<lpm_modes>`, wakeup from MAIN GPIO1_10 can be triggered
by grounding Pin 33 on J3 User Expansion Connector.

.. ifconfig:: CONFIG_part_variant in ('AM62LX')

The reference configuration for Main GPIO wakeup can be found under
gpio_key node in
`k3-am62l3-evm.dts <https://git.ti.com/cgit/ti-linux-kernel/ti-linux-kernel/tree/arch/arm64/boot/dts/ti/k3-am62l3-evm.dts?h=11.02.06#n50>`__

.. code-block:: console
gpio_key {
compatible = "gpio-keys";
autorepeat;
pinctrl-names = "default";
pinctrl-0 = <&usr_button_pins_default>;
switch {
label = "User Key";
linux,code = <BTN_0>;
interrupts-extended = <&main_gpio0 90 IRQ_TYPE_EDGE_RISING>,
<&main_pmx0 0x1ac>;
interrupt-names = "irq", "wakeup";
};
};
The IRQ is chained to the pinctrl driver using the second
interrupts-extended entry. The wake IRQ framework in Linux works so that the
second entry gets marked as a wakeup source, and then the pinctrl driver is
informed that the pad, 0x1ac in this case, is to be configured as a wakeup
pad when system enters Deep Sleep.

To use main_gpio as a wakeup source, ensure gpio is a wake-irq in
/proc/interrupts:

.. code-block:: console
root@<machine>:~# grep wakeup /proc/interrupts
299: 0 0 pinctrl 428 Edge User Key:wakeup
Once the system has entered Deep Sleep as shown in the
:ref:`LPM section<lpm_modes>`, wakeup from MAIN GPIO0_90 can be triggered
by pressing button SW5.

*********
WKUP UART
*********

.. ifconfig:: CONFIG_part_variant in ('AM62LX')
The UART in WKUP domain is capable of waking up the system.

WKUP UART wakeup is not yet supported on AM62LX.
In order to use WKUP UART as a wakeup source, it needs to be configured
in a generic way using the ti-sysc interconnect target module driver.
The reference configuration can be found under target-module in
`k3-am62-wakeup.dtsi <https://git.ti.com/cgit/ti-linux-kernel/ti-linux-kernel/tree/arch/arm64/boot/dts/ti/k3-am62-wakeup.dtsi?h=11.01.05#n46>`__
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Suggested change
`k3-am62-wakeup.dtsi <https://git.ti.com/cgit/ti-linux-kernel/ti-linux-kernel/tree/arch/arm64/boot/dts/ti/k3-am62-wakeup.dtsi?h=11.01.05#n46>`__
`k3-am62-wakeup.dtsi <https://git.ti.com/cgit/ti-linux-kernel/ti-linux-kernel/tree/arch/arm64/boot/dts/ti/k3-am62-wakeup.dtsi?h=11.02.06#n46>`__

similar to https://github.com/TexasInstruments/processor-sdk-doc/pull/537/files#diff-8f2199cf05ab6b3988cb3fcc96ced8b7635d84f112acd4b1e04e471870bb3a35R477


.. ifconfig:: CONFIG_part_variant in ('AM62X', 'AM62AX', 'AM62PX')

The UART in WKUP domain is capable of waking up the system from Deep
Sleep and MCU Only modes.
WKUP UART is generally available on the third serial port
(/dev/ttyUSB2) and by default it only shows output from DM R5.

In order to use WKUP UART as a wakeup source, it needs to be configured
in a generic way using the ti-sysc interconnect target module driver.
The reference configuration can be found under target-module in
`k3-am62-wakeup.dtsi <https://git.ti.com/cgit/ti-linux-kernel/ti-linux-kernel/tree/arch/arm64/boot/dts/ti/k3-am62-wakeup.dtsi?h=11.01.05#n46>`__
.. ifconfig:: CONFIG_part_variant in ('AM62LX')

WKUP UART is generally available on the third serial port
(/dev/ttyUSB2) and by default it only shows output from DM R5.
(/dev/ttyUSB2).

Once the system has entered Deep Sleep or MCU Only mode as shown in the
:ref:`LPM section<lpm_modes>`, wakeup from WKUP UART can be triggered
by doing *any key press* on the WKUP UART terminal. No output will be
visible on the WKUP UART terminal, but Linux resume messages will be
printed on the MAIN UART terminal.
Once the system has entered the specified low power mode as shown in the
:ref:`LPM section<lpm_modes>`, wakeup from WKUP UART can be triggered
by doing *any key press* on the WKUP UART terminal. No output will be
visible on the WKUP UART terminal, but Linux resume messages will be
printed on the MAIN UART terminal.


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