Message-Id: <20251001-topic-am62-dt-partialio-v6-15-v3-0-7095fe263ece@baylibre.com>
Date: Wed, 01 Oct 2025 16:34:12 +0200
From: "Markus Schneider-Pargmann (TI.com)" <msp@...libre.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>
Cc: linux-arm-kernel@...ts.infradead.org, devicetree@...r.kernel.org, 
 linux-kernel@...r.kernel.org, Vishal Mahaveer <vishalm@...com>, 
 Kevin Hilman <khilman@...libre.com>, Dhruva Gole <d-gole@...com>, 
 Sebin Francis <sebin.francis@...com>, Kendall Willis <k-willis@...com>, 
 Akashdeep Kaur <a-kaur@...com>, 
 "Markus Schneider-Pargmann (TI.com)" <msp@...libre.com>
Subject: [PATCH v3 0/6] arm64: dts: ti: k3-am62: Add wakeup-sources for low
 power modes

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. m_can driver series: Implements device-specific wakeup functionality
   for m_can devices, allowing them to be set as wakeup sources.
    https://gitlab.baylibre.com/msp8/linux/-/tree/topic/mcan-wakeup-source/v6.17?ref_type=heads
    https://lore.kernel.org/r/20250812-topic-mcan-wakeup-source-v6-12-v8-0-6972a810d63b@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/v6.17?ref_type=heads

Devicetree Bindings
-------------------
This series depends on the dt-schema pull request that adds bindings for
system-idle-states and updates the binding for wakeup-source:
  https://github.com/devicetree-org/dt-schema/pull/150

This is merged now in upstream dt-schema. These new bindings allow us to
define the system states and reference them from device wakeup-source
properties.

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/v6.17?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 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 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@...libre.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  | 71 ++++++++++++++++++++++++++++++++
 arch/arm64/boot/dts/ti/k3-am62p.dtsi     | 27 ++++++++++++
 arch/arm64/boot/dts/ti/k3-am62p5-sk.dts  | 71 ++++++++++++++++++++++++++++++++
 6 files changed, 278 insertions(+)
---
base-commit: 24c4d4041c2ec11c47baf6ea54f9379cf88809fc
change-id: 20250415-topic-am62-dt-partialio-v6-15-327dd1ff17da
prerequisite-change-id: 20241009-topic-mcan-wakeup-source-v6-12-8c1d69931bd8:v10
prerequisite-patch-id: 40ff771d13dccae91c04ab120aa1b5e406b66e47
prerequisite-patch-id: 830b339ea452edd750b04f719da91e721be630cb
prerequisite-patch-id: 2c9142d2bc47e64c49b7b8a7ca20a62a0be14870
prerequisite-patch-id: aa64f7e9fcc3fcbb3cb871a05a07f398f3aa8231

Best regards,
-- 
Markus Schneider-Pargmann (TI.com) <msp@...libre.com>

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