Message-Id: <20250812-topic-am62-dt-partialio-v6-15-v2-0-25352364a0ac@baylibre.com>
Date: Tue, 12 Aug 2025 11:15:19 +0200
From: Markus Schneider-Pargmann <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 <msp@...libre.com>
Subject: [PATCH v2 0/7] 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 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 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 <msp@...libre.com>
---
Markus Schneider-Pargmann (7):
      arm64: dts: ti: k3-pinctrl: Add WKUP_EN flag
      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 ++++++++++++++++++++++++++++++++
 arch/arm64/boot/dts/ti/k3-pinctrl.h      |  2 +
 7 files changed, 280 insertions(+)
---
base-commit: 062b3e4a1f880f104a8d4b90b767788786aa7b78
change-id: 20250415-topic-am62-dt-partialio-v6-15-327dd1ff17da
prerequisite-change-id: 20241009-topic-mcan-wakeup-source-v6-12-8c1d69931bd8:v8
prerequisite-patch-id: 02b7142f56c849c9a3faab2d2871805febd647aa
prerequisite-patch-id: 830b339ea452edd750b04f719da91e721be630cb
prerequisite-patch-id: 2c9142d2bc47e64c49b7b8a7ca20a62a0be14870
prerequisite-patch-id: f7652a616dca17fd5e4a7e5cba59de6a6a36079f

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

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