Hi,
This series adds devicetree changes needed for Partial-IO support on TI
am62, am62a, and am62p SoCs. It defines system states for various low
power modes and configures the wakeup-sources for devices in the CANUART
group. Depending on the SoC and board details, some low power modes may
not be available, so the wakeup-sources are described in the board
files. The series also adds the necessary pinctrl settings required for
proper wakeup functionality.
Partial-IO Overview
------------------
Partial-IO is a low power system state in which nearly everything is
turned off except the pins of the CANUART group (mcu_mcan0, mcu_mcan1,
wkup_uart0 and mcu_uart0). These devices can trigger a wakeup of the
system on pin activity. Note that this does not resume the system as the
DDR is off as well. So this state can be considered a power-off state
with wakeup capabilities.
A documentation can also be found in section 6.2.4 in the TRM:
https://www.ti.com/lit/pdf/spruiv7
Implementation Details
----------------------
The complete Partial-IO feature requires three coordinated series, each
handling a different aspect of the implementation:
1. [MERGED] m_can driver series: Implements device-specific wakeup
functionality for m_can devices, allowing them to be set as wakeup
sources. This is available in linux-next now.
https://lore.kernel.org/r/20251001-topic-mcan-wakeup-source-v6-12-v10-0-4ab508ac5d1e@baylibre.com
2. This series (devicetree): Defines system states and wakeup sources in
the devicetree for am62, am62a and am62p.
3. TI-SCI firmware series: Implements the firmware interface to enter
Partial-IO mode when appropriate wakeup sources are enabled.
https://gitlab.baylibre.com/msp8/linux/-/tree/topic/tisci-partialio/v6.18?ref_type=heads
Testing
-------
A test branch is available here that includes all patches required to
test Partial-IO:
https://gitlab.baylibre.com/msp8/linux/-/tree/integration/am62-partialio/v6.18?ref_type=heads
After enabling Wake-on-LAN the system can be powered off and will enter
the Partial-IO state in which it can be woken up by activity on the
specific pins:
ethtool -s can0 wol p
ethtool -s can1 wol p
poweroff
I tested these patches on am62-lp-sk.
Best,
Markus
Previous versions
-----------------
- Link to v4: https://lore.kernel.org/r/20251030-topic-am62-dt-partialio-v6-15-v4-0-6b520dfa8591@baylibre.com
- Link to v3: https://lore.kernel.org/r/20251001-topic-am62-dt-partialio-v6-15-v3-0-7095fe263ece@baylibre.com
- Link to v2: https://lore.kernel.org/r/20250812-topic-am62-dt-partialio-v6-15-v2-0-25352364a0ac@baylibre.com
- Link to v1: https://lore.kernel.org/r/20250421-topic-am62-dt-partialio-v6-15-v1-0-6ced30aafddb@baylibre.com
- As part of the series "firmware: ti_sci: Partial-IO support"
https://lore.kernel.org/r/20250306-topic-am62-partialio-v6-12-b4-v5-0-f9323d3744a2@baylibre.com
Changes in v5:
- Disable mcu_mcan* on am62a-sk and am62p-sk by default.
Changes in v4:
- Rebase to next-20251029
Changes in v3:
- Drop patch to add WKUP_EN and rebase to linux-next to base on the
patch that accepted which adds PIN_WKUP_EN instead
https://lore.kernel.org/all/20250909044108.2541534-1-a-kaur@ti.com/
- Fix small typos in the commit messages
- Use AM62AX_MCU_IOPAD for am62a and AM62PX_MCU_IOPAD for am62p
Changes in v2:
- Combine k3-am62a7-sk.dts devicetree nodes with existing ones
- Combine k3-am62p5-sk.dts devicetree nodes with existing ones
- Update the idle-state-name properties to the new names from the
dt-schema
- Rebase to 6.17-rc1
Signed-off-by: Markus Schneider-Pargmann (TI.com) <msp@baylibre.com>
---
Markus Schneider-Pargmann (TI.com) (6):
arm64: dts: ti: k3-am62: Define possible system states
arm64: dts: ti: k3-am62a: Define possible system states
arm64: dts: ti: k3-am62p: Define possible system states
arm64: dts: ti: k3-am62-lp-sk: Set wakeup-source system-states
arm64: dts: ti: k3-am62a7-sk: Set wakeup-source system-states
arm64: dts: ti: k3-am62p5-sk: Set wakeup-source system-states
arch/arm64/boot/dts/ti/k3-am62-lp-sk.dts | 60 +++++++++++++++++++++++++++
arch/arm64/boot/dts/ti/k3-am62.dtsi | 22 ++++++++++
arch/arm64/boot/dts/ti/k3-am62a.dtsi | 27 +++++++++++++
arch/arm64/boot/dts/ti/k3-am62a7-sk.dts | 69 ++++++++++++++++++++++++++++++++
arch/arm64/boot/dts/ti/k3-am62p.dtsi | 27 +++++++++++++
arch/arm64/boot/dts/ti/k3-am62p5-sk.dts | 69 ++++++++++++++++++++++++++++++++
6 files changed, 274 insertions(+)
---
base-commit: c9a389ffad27e7847c69f4d2b67ba56b77190209
change-id: 20250415-topic-am62-dt-partialio-v6-15-327dd1ff17da
Best regards,
--
Markus Schneider-Pargmann (TI.com) <msp@baylibre.com>