[PATCH v1 0/4] Enable Serial on SA8255p Qualcomm platforms

From: Praveen Talari

Date: Mon Nov 10 2025 - 05:14:58 EST


PM runtime support was previously added to the serial driver but had to
be reverted due to wakeup IRQ storms and deadlock issues observed on the
RB1 platform.

Reference:
https://lore.kernel.org/all/DC0D53ZTNOBU.E8LSD5E5Z8TX@xxxxxxxxxx/

This patch series reintroduces PM runtime support for UART on SA8255p
with fixes to resolve those issues.

The Qualcomm automotive SA8255p SoC relies on firmware to configure
platform resources, including clocks, interconnects and TLMM.
The driver requests resources operations over SCMI using power
and performance protocols.

The SCMI power protocol enables or disables resources like clocks,
interconnect paths, and TLMM (GPIOs) using runtime PM framework APIs,
such as resume/suspend, to control power states(on/off).

The SCMI performance protocol manages UART baud rates, with each baud
rate represented by a performance level. The driver uses the
dev_pm_opp_set_level() API to request the desired baud rate by
specifying the performance level.

Praveen Talari (4):
arm64: dts: qcom: qrb2210-rb1: Fix UART3 wakeup IRQ storm
pinctrl: qcom: msm: Fix potential deadlock in pinmux configuration
serial: qcom-geni: Enable PM runtime for serial driver
serial: qcom-geni: Enable Serial on SA8255p Qualcomm platforms

arch/arm64/boot/dts/qcom/qrb2210-rb1.dts | 2 +-
drivers/pinctrl/qcom/pinctrl-msm.c | 2 +-
drivers/tty/serial/qcom_geni_serial.c | 178 ++++++++++++++++++++---
3 files changed, 163 insertions(+), 19 deletions(-)


base-commit: ab40c92c74c6b0c611c89516794502b3a3173966
--
2.34.1