Message-ID: <20260122-b4-uart-daisy-chain-dts-v4-0-cfdabdf5e6c1@ti.com>
Date: Thu, 22 Jan 2026 11:38:30 -0600
From: Kendall Willis <k-willis@...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>,
	<d-gole@...com>, <msp@...libre.com>
CC: <vishalm@...com>, <sebin.francis@...com>, <khilman@...libre.com>,
	<a-kaur@...com>, <s-kochidanadu@...com>,
	<linux-arm-kernel@...ts.infradead.org>, <devicetree@...r.kernel.org>,
	<linux-kernel@...r.kernel.org>, Kendall Willis <k-willis@...com>
Subject: [PATCH v4 0/4] arm64: dts: ti: k3-am62: Support Main UART wakeup

This series adds wakeup support for the Main UART in the device tree of
the TI AM62 family of devices. It defines the specific pins and pinctrl
states needed to wakeup the system from the Main UART via I/O
daisy-chaining. The wakeup-source property is configured to describe the
low power modes the system can wakeup from using the Main UART.

Dependency
----------
This series depends on the "serial: 8250: omap: set out-of-band wakeup if
wakeup pinctrl exists" [1] patch. This series should NOT be merged until
"serial: 8250: omap: set out-of-band wakeup if wakeup pinctrl exists"
is merged.

Testing
-------
Tested on a AM62P SK EVM board and a AM62L EVM board with all the above
mentioned series implemented. Suspend/resume verified with the Main UART
wakeup source by entering a keypress on the console.

This github branch has all the necessary patches to test the series
using v6.19-rc1:
https://github.com/kwillis01/linux/tree/v6.19/uart-daisy-chain/all

[1] https://lore.kernel.org/all/20260116-uart-wakeup-v2-1-0078ae9996e4@ti.com/

---
Changes in v4:
- Dropped AM62L system idle states patch.
- Removed AM62L system idle states from the wakeup-source property.
- Link to v3: https://lore.kernel.org/r/20260106-b4-uart-daisy-chain-dts-v3-0-398a66258f2c@ti.com

Changes in v3:
- Reword commits to include the logic of how the "default" and "wakeup"
  pinctrl states are used.
- Revert pin logic so that main_uart0_pins_default and uart0_pins_default
  are untouched.
- Remove main_uart0_rx_pins_default and uart0_rx_pins_default.
- Combine main_uart0 RX wakeup pin and main_uart0 TX pin into one group of
  pins called main_uart0_pins_wakeup or uart0_pins_wakeup.
- Revert pinctrl-0 to only include main_uart0_pins_wakeup or
  uart0_pins_wakeup.
- Change pinctrl-1 to only include main_uart0_pins_wakeup or
  uart0_pins_wakeup.
- Link to v2: https://lore.kernel.org/r/20251230-b4-uart-daisy-chain-dts-v2-0-fa5257ec54bb@ti.com

Changes in v2:
- Define AM62L system idle states
- Enable Main UART wakeup for AM62L SoC
- Rebase to v6.19-rc3
- Link to v1: https://lore.kernel.org/all/20250904212827.3730314-1-k-willis@ti.com/

---
Kendall Willis (4):
      arm64: dts: ti: k3-am62x-sk-common: Enable Main UART wakeup
      arm64: dts: ti: k3-am62a7-sk: Enable Main UART wakeup
      arm64: dts: ti: k3-am62p5-sk: Enable Main UART wakeup
      arm64: dts: ti: k3-am62l3-evm: Enable Main UART wakeup

 arch/arm64/boot/dts/ti/k3-am62a7-sk.dts        | 13 ++++++++++++-
 arch/arm64/boot/dts/ti/k3-am62l3-evm.dts       | 11 ++++++++++-
 arch/arm64/boot/dts/ti/k3-am62p5-sk.dts        | 13 ++++++++++++-
 arch/arm64/boot/dts/ti/k3-am62x-sk-common.dtsi | 13 ++++++++++++-
 4 files changed, 46 insertions(+), 4 deletions(-)
---
base-commit: c8a4a774a9b0d2c86593492625874e27e9cbc9a9
change-id: 20251230-b4-uart-daisy-chain-dts-d01aa40560b2
prerequisite-change-id: 20251230-uart-wakeup-00faeac7c994:v2
prerequisite-patch-id: f886c56dbb291b710ec07001ce79b0016c233e1c

Best regards,
-- 
Kendall Willis <k-willis@...com>

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