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LPM CAN I/O changes + update URLs #661

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124a9d3
style(pm_wakeup_sources): reword CAN wakeup section
kwillis01 Apr 10, 2026
02867c5
style(pm_low_power_modes): reword Partial IO section
kwillis01 Apr 10, 2026
6f90f4f
feat(power): update steps to enable CAN wakeup from LPM
kwillis01 Apr 10, 2026
ed4ef5a
fix(pm_wakeup_sources): update Main UART wakeup code
kwillis01 Apr 13, 2026
cffee50
chore(Power_Management): update URLs to 12.00.00.08
kwillis01 Apr 13, 2026
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4 changes: 2 additions & 2 deletions source/linux/Foundational_Components/Power_Management/pm_cpuidle.rst
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Expand Up @@ -32,7 +32,7 @@ transition to the selected state.
.. rubric:: Enable Standby

In order to enable Standby the `k3-am62x-sk-lpm-standby.dtso
<https://git.ti.com/cgit/ti-linux-kernel/ti-linux-kernel/tree/arch/arm64/boot/dts/ti/k3-am62x-sk-lpm-standby.dtso?h=11.02.08>`__
<https://git.ti.com/cgit/ti-linux-kernel/ti-linux-kernel/tree/arch/arm64/boot/dts/ti/k3-am62x-sk-lpm-standby.dtso?h=12.00.00.07>`__
overlay should be applied. Refer to :ref:`How to enable DT overlays
<howto_dt_overlays>` for more details. More information on what the overlay
does is in the :ref:`linux-device-tree-label` section.
Expand Down Expand Up @@ -112,7 +112,7 @@ transition to the selected state.

In order to implement Standby in Linux, an idle-states node has to be added
and then referenced by the CPU node. The `k3-am62x-sk-lpm-standby.dtso
<https://git.ti.com/cgit/ti-linux-kernel/ti-linux-kernel/tree/arch/arm64/boot/dts/ti/k3-am62x-sk-lpm-standby.dtso?h=11.02.08>`__
<https://git.ti.com/cgit/ti-linux-kernel/ti-linux-kernel/tree/arch/arm64/boot/dts/ti/k3-am62x-sk-lpm-standby.dtso?h=12.00.00.07>`__
can be used as a reference.

.. code-block:: dts
Expand Down
35 changes: 16 additions & 19 deletions source/linux/Foundational_Components/Power_Management/pm_low_power_modes.rst
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Expand Up @@ -48,16 +48,13 @@
Only AM62 LP-SK EVM supports Partial I/O mode.

The reference implementation in this SDK implements Partial I/O as a
poweroff state. On poweroff, Linux ti_sci driver checks the potential
Partial I/O wakeup sources for being enabled. If one of the wakeup
sources is found to be enabled, Partial I/O is entered instead of poweroff.
poweroff state. On poweroff, Linux ti_sci driver checks if any potential

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[RedHat.Hyphens] Use 'power-off' rather than 'poweroff'.

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{"message": "[RedHat.Hyphens] Use 'power-off' rather than 'poweroff'.", "location": {"path": "source/linux/Foundational_Components/Power_Management/pm_low_power_modes.rst", "range": {"start": {"line": 51, "column": 20}}}, "severity": "WARNING"}

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[RedHat.Hyphens] Use 'power-off' rather than 'poweroff'.

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{"message": "[RedHat.Hyphens] Use 'power-off' rather than 'poweroff'.", "location": {"path": "source/linux/Foundational_Components/Power_Management/pm_low_power_modes.rst", "range": {"start": {"line": 51, "column": 1}}}, "severity": "WARNING"}
Partial I/O wakeup sources are enabled. If one of the wakeup sources is

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[RedHat.PassiveVoice] 'is enabled' is passive voice. In general, use active voice. Consult the style guide for acceptable use of passive voice.

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{"message": "[RedHat.PassiveVoice] 'is enabled' is passive voice. In general, use active voice. Consult the style guide for acceptable use of passive voice.", "location": {"path": "source/linux/Foundational_Components/Power_Management/pm_low_power_modes.rst", "range": {"start": {"line": 52, "column": 70}}}, "severity": "INFO"}

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[RedHat.PassiveVoice] 'are enabled' is passive voice. In general, use active voice. Consult the style guide for acceptable use of passive voice.

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{"message": "[RedHat.PassiveVoice] 'are enabled' is passive voice. In general, use active voice. Consult the style guide for acceptable use of passive voice.", "location": {"path": "source/linux/Foundational_Components/Power_Management/pm_low_power_modes.rst", "range": {"start": {"line": 52, "column": 28}}}, "severity": "INFO"}
enabled, Partial I/O is entered instead of poweroff.

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{"message": "[RedHat.Hyphens] Use 'power-off' rather than 'poweroff'.", "location": {"path": "source/linux/Foundational_Components/Power_Management/pm_low_power_modes.rst", "range": {"start": {"line": 53, "column": 44}}}, "severity": "WARNING"}

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[RedHat.PassiveVoice] 'is entered' is passive voice. In general, use active voice. Consult the style guide for acceptable use of passive voice.

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{"message": "[RedHat.PassiveVoice] 'is entered' is passive voice. In general, use active voice. Consult the style guide for acceptable use of passive voice.", "location": {"path": "source/linux/Foundational_Components/Power_Management/pm_low_power_modes.rst", "range": {"start": {"line": 53, "column": 22}}}, "severity": "INFO"}
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@StaticRocket StaticRocket Apr 14, 2026

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This SDK implements Partial I/O as a power-off state. The Linux ti_sci
driver will enter Partial I/O if any Partial I/O wakeup sources are preset.


The following wakeup sources have been configured for Partial I/O:
mcu_uart0, mcu_mcan0, and mcu_mcan1. Partial I/O mode 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=11.02.08>`__
overlay is loaded. Please refer to :ref:`How to enable DT overlays<howto_dt_overlays>` for more details.

After Linux boots, the MCAN wakeup for Partial I/O is enabled.
Wakeup sources mcu_mcan0 and mcu_mcan1 have been configured for Partial

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{"message": "[RedHat.PassiveVoice] 'been configured' is passive voice. In general, use active voice. Consult the style guide for acceptable use of passive voice.", "location": {"path": "source/linux/Foundational_Components/Power_Management/pm_low_power_modes.rst", "range": {"start": {"line": 55, "column": 45}}}, "severity": "INFO"}
I/O. For more information on enabling CAN, refer to

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[RedHat.TermsSuggestions] Depending on the context, consider using 'see' rather than 'refer to'.

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{"message": "[RedHat.TermsSuggestions] Depending on the context, consider using 'see' rather than 'refer to'.", "location": {"path": "source/linux/Foundational_Components/Power_Management/pm_low_power_modes.rst", "range": {"start": {"line": 56, "column": 44}}}, "severity": "INFO"}

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

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{"message": "[RedHat.Definitions] Define acronyms and abbreviations (such as 'CAN') on first occurrence if they're likely to be unfamiliar.", "location": {"path": "source/linux/Foundational_Components/Power_Management/pm_low_power_modes.rst", "range": {"start": {"line": 56, "column": 39}}}, "severity": "INFO"}

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{"message": "[RedHat.TermsSuggestions] Depending on the context, consider using 'information about' rather than 'information on'.", "location": {"path": "source/linux/Foundational_Components/Power_Management/pm_low_power_modes.rst", "range": {"start": {"line": 56, "column": 15}}}, "severity": "INFO"}
:ref:`CAN I/O Daisy Chain<pm_wakeup_sources_can>`.
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Wakeup sources mcu_mcan0 and mcu_mcan1 have support for Partial
I/O. For more information about enabling CAN, see
:ref:CAN I/O Daisy Chain<pm_wakeup_sources_can>.


Enter Partial I/O mode with the following command:

Expand All @@ -70,10 +67,11 @@

.. code-block:: text

[ 51.698039] systemd-shutdown[1]: Powering off.
[ 51.769478] reboot: Power down
[ 74.310565] systemd-shutdown[1]: Powering off.
[ 74.396204] reboot: Power down
[ 74.399358] ti-sci 44043000.system-controller: Entering Partial-IO because a powered wakeup-enabled device was found.

The system has entered Partial I/O and can only be woken up with an
The system has entered Partial I/O and can only be woken up with
activity on the I/O pin programmed for wakeup. For example, if mcu_mcan0
wakeup was enabled, grounding Pin 22 of J8 MCU Header will wakeup the
system and it will go through a normal Linux boot process.
Expand Down Expand Up @@ -113,13 +111,12 @@

.. important:: Jumper J12 should be connected on SK to enable system to enter I/O Only plus DDR mode.

The wakeup sources that can be used to wake the system from I/O Only Plus
DDR are mcu_uart0, mcu_mcan0, mcu_mcan1 and wkup_uart0. To use the mcu_mcan0
and mcu_mcan1 wakeup sources, apply the
`k3-am62x-sk-lpm-io-ddr-wkup-sources.dtso <https://git.ti.com/cgit/ti-linux-kernel/ti-linux-kernel/tree/arch/arm64/boot/dts/ti/k3-am62x-sk-lpm-io-ddr-wkup-sources.dtso?h=11.02.08>`__
overlay. Please refer to :ref:`How to enable DT overlays<howto_dt_overlays>`
for more details. To use the mcu_uart0 and wkup_uart0 wakeup sources, direct
register writes can be used to enable wakeup after Linux boots.
The wakeup sources that can be used to wake the system from I/O Only
Plus DDR are mcu_uart0, mcu_mcan0, mcu_mcan1 and wkup_uart0. To use the
mcu_mcan0 and mcu_mcan1 wakeup sources, refer to
:ref:`CAN I/O Daisy Chain<pm_wakeup_sources_can>`.
To use the mcu_uart0 and wkup_uart0 wakeup sources, direct register
writes can be used to enable wakeup after Linux boots.

.. rubric:: Following commands set the wakeup EN bit, enable receive for pad in PADCONFIG register and can
be used to enable wakeup from mcu_uart0 and wkup_uart0 pins respectively.
Expand Down
4 changes: 2 additions & 2 deletions source/linux/Foundational_Components/Power_Management/pm_sw_arch.rst
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Expand Up @@ -151,8 +151,8 @@ Specifically, checking of constraints is done at two levels:

The code enabling the constraints framework can be found in:

#. TISCI PM Domain driver: https://git.ti.com/cgit/ti-linux-kernel/ti-linux-kernel/tree/drivers/pmdomain/ti/ti_sci_pm_domains.c?h=11.02.08
#. TISCI driver: https://git.ti.com/cgit/ti-linux-kernel/ti-linux-kernel/tree/drivers/firmware/ti_sci.c?h=11.02.08
#. TISCI PM Domain driver: https://git.ti.com/cgit/ti-linux-kernel/ti-linux-kernel/tree/drivers/pmdomain/ti/ti_sci_pm_domains.c?h=12.00.00.07
#. TISCI driver: https://git.ti.com/cgit/ti-linux-kernel/ti-linux-kernel/tree/drivers/firmware/ti_sci.c?h=12.00.00.07

Examples of adding constraints from the remote core side are being implemented and will
be enabled in future release.
Expand Down
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