The NXP S32 family provides a System Timer Module (STM), a 32-bit
free-running counter clocked from a peripheral clock. The STM includes
a prescaler and one or more compare channels generating optional
interrupts. When used as a generic hardware counter, only the main
free-running counter is required, while the compare channels are
typically unused.
On S32G2 devices, the STM is exposed as a simple counter block that
can operate continuously and be shared across subsystems such as the
Linux kernel, firmware components running on Cortex-M7 cores, or other
co-processors. The counter can be read atomically and provides a
stable timestamp source to correlate events occurring in different
execution contexts.
The Linux kernel controls the STM through a memory-mapped interface,
configuring the prescaler, enabling or disabling the counter, and
accounting for wrap-arounds. Other subsystems access the counter in
read-only mode, making it a shared timestamp reference across the
platform.
This driver adds support for the STM when used as a counter on S32G2
platforms. The device is described in the device tree using the
following compatible:
compatible = "nxp,s32g2-stm-cnt";
The driver exposes basic counter functionality: start, stop, reset,
prescaler configuration, and overflow handling.
Changelog:
* v2
- Added Rob's tag
** kbuild
- Reordered alphabetically the headers
- Added bitfield.h header
- Use DEFINE_SIMPLE_DEV_PM_OPS() and pm_sleep_ptr()
Daniel Lezcano (3):
counters: Reorder the Makefile
dt-bindings: counter: Add NXP System Timer Module Counter
counter: Add STM based counter
.../bindings/counter/nxp,s32g2-stm-cnt.yaml | 64 +++
drivers/counter/Kconfig | 10 +
drivers/counter/Makefile | 21 +-
drivers/counter/nxp-stm-cnt.c | 386 ++++++++++++++++++
4 files changed, 472 insertions(+), 9 deletions(-)
create mode 100644 Documentation/devicetree/bindings/counter/nxp,s32g2-stm-cnt.yaml
create mode 100644 drivers/counter/nxp-stm-cnt.c
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2.43.0