[PATCH v2] clocksource: move NXP timer selection to drivers/clocksource

[PATCH v2] clocksource: move NXP timer selection to drivers/clocksource

[Enric Balletbo i Serra]

From: Enric Balletbo i Serra <eballetb@redhat.com>

The Kconfig logic for selecting the scheduler clocksource on
NXP Vybrid (VF610) uses a `choice` block restricted to 32-bit ARM. This
prevents 64-bit architectures, such as the NXP S32 family, from enabling
the NXP Periodic Interrupt Timer (PIT) driver (CONFIG_NXP_PIT_TIMER).

Relocate the NXP clocksource selection from arch/arm/mach-imx/Kconfig to
drivers/clocksource/Kconfig. This allows the configuration to be shared
across different architectures.

Update the selection to include support for ARCH_S32 and add a "None"
option to allow using the standard ARM Architected Timer. The Vybrid
Global Timer option is restricted to ARCH_MULTI_V7 SOC_VF610 platforms
to prevent it from being visible on Cortex-M4 builds, which lack the
ARM Global Timer hardware.

Fixes: bee33f22d7c3 ("clocksource/drivers/nxp-pit: Add NXP Automotive s32g2 / s32g3 support")
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Signed-off-by: Enric Balletbo i Serra <eballetb@redhat.com>
---
Changes in v2:
- Fix VF_USE_ARM_GLOBAL_TIMER dependency: use ARCH_MULTI_V7 instead of
  ARM to prevent the option from being visible on Cortex-M4 builds
  (Sashiko AI review)
- Link to v1: https://lore.kernel.org/r/20260302-fix-nxp-timer-v1-1-af4bc62d4ffa@redhat.com
---
 arch/arm/mach-imx/Kconfig   | 21 ---------------------
 drivers/clocksource/Kconfig | 30 ++++++++++++++++++++++++++++++
 2 files changed, 30 insertions(+), 21 deletions(-)

diff --git a/arch/arm/mach-imx/Kconfig b/arch/arm/mach-imx/Kconfig
index 6ea1bd55acf8..a361840d7a04 100644
--- a/arch/arm/mach-imx/Kconfig
+++ b/arch/arm/mach-imx/Kconfig
@@ -227,27 +227,6 @@ config SOC_VF610
 	help
 	  This enables support for Freescale Vybrid VF610 processor.
 
-choice
-	prompt "Clocksource for scheduler clock"
-	depends on SOC_VF610
-	default VF_USE_ARM_GLOBAL_TIMER
-
-	config VF_USE_ARM_GLOBAL_TIMER
-		bool "Use ARM Global Timer"
-		depends on ARCH_MULTI_V7
-		select ARM_GLOBAL_TIMER
-		select CLKSRC_ARM_GLOBAL_TIMER_SCHED_CLOCK
-		help
-		  Use the ARM Global Timer as clocksource
-
-	config VF_USE_PIT_TIMER
-		bool "Use PIT timer"
-		select NXP_PIT_TIMER
-		help
-		  Use SoC Periodic Interrupt Timer (PIT) as clocksource
-
-endchoice
-
 endif
 
 endif
diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig
index d1a33a231a44..15c02d3e9dbf 100644
--- a/drivers/clocksource/Kconfig
+++ b/drivers/clocksource/Kconfig
@@ -793,4 +793,34 @@ config RTK_SYSTIMER
 	  this option only when building for a Realtek platform or for compilation
 	  testing.
 
+choice
+	prompt "NXP clocksource for scheduler clock"
+	depends on SOC_VF610 || ARCH_S32
+	# Default to Global Timer for Vybrid (32-bit)
+	default VF_USE_ARM_GLOBAL_TIMER if SOC_VF610
+	# Default to None for S32 (64-bit)
+	default VF_TIMER_NONE if ARCH_S32
+
+	config VF_USE_ARM_GLOBAL_TIMER
+		bool "Use NXP Vybrid Global Timer"
+		depends on ARCH_MULTI_V7 && SOC_VF610
+		select ARM_GLOBAL_TIMER
+		select CLKSRC_ARM_GLOBAL_TIMER_SCHED_CLOCK
+		help
+		  Use the NXP Vybrid Global Timer as clocksource.
+
+	config VF_USE_PIT_TIMER
+		bool "Use NXP PIT timer"
+		select NXP_PIT_TIMER
+		help
+		  Use NXP Periodic Interrupt Timer (PIT) as clocksource.
+
+	config VF_TIMER_NONE
+		bool "None (Use standard Arch Timer)"
+		help
+		  Do not use any specific NXP timer driver. Use the standard
+		  ARM Architected Timer instead.
+
+endchoice
+
 endmenu

---
base-commit: 7fd2df204f342fc17d1a0bfcd474b24232fb0f32
change-id: 20260302-fix-nxp-timer-9cb1fbd7afcd

Best regards,
-- 
Enric Balletbo i Serra <eballetb@redhat.com>

Re: [PATCH v2] clocksource: move NXP timer selection to drivers/clocksource

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] `VF_TIMER_NONE` is selectable on Vybrid (`SOC_VF610`) platforms but relies on hardware that does not exist on those platforms.
--

commit 7af32213cbfafc4c689a6d3a071f0b9a62837a94
Author: Enric Balletbo i Serra <eballetb@redhat.com>

clocksource: move NXP timer selection to drivers/clocksource

This commit relocates the NXP clocksource selection from the ARM mach-imx
architecture Kconfig to the drivers/clocksource Kconfig so it can be shared
across architectures. It updates the choice block to support ARCH_S32 and
adds a None option to allow using the standard ARM Architected Timer.

> diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig
> index d1a33a231a44c..15c02d3e9dbff 100644
> --- a/drivers/clocksource/Kconfig
> +++ b/drivers/clocksource/Kconfig
[ ... ]
> +choice
> +	prompt "NXP clocksource for scheduler clock"
> +	depends on SOC_VF610 || ARCH_S32
> +	# Default to Global Timer for Vybrid (32-bit)
> +	default VF_USE_ARM_GLOBAL_TIMER if SOC_VF610
> +	# Default to None for S32 (64-bit)
> +	default VF_TIMER_NONE if ARCH_S32
> +
> +	config VF_USE_ARM_GLOBAL_TIMER
> +		bool "Use NXP Vybrid Global Timer"
> +		depends on ARCH_MULTI_V7 && SOC_VF610
> +		select ARM_GLOBAL_TIMER
> +		select CLKSRC_ARM_GLOBAL_TIMER_SCHED_CLOCK
> +		help
> +		  Use the NXP Vybrid Global Timer as clocksource.
> +
> +	config VF_USE_PIT_TIMER
> +		bool "Use NXP PIT timer"
> +		select NXP_PIT_TIMER
> +		help
> +		  Use NXP Periodic Interrupt Timer (PIT) as clocksource.
> +
> +	config VF_TIMER_NONE
> +		bool "None (Use standard Arch Timer)"
> +		help
> +		  Do not use any specific NXP timer driver. Use the standard
> +		  ARM Architected Timer instead.

Does this allow VF_TIMER_NONE to be selected on Vybrid (SOC_VF610) platforms?

Since the choice block itself depends on SOC_VF610 || ARCH_S32, this option
is visible on Vybrid builds. If selected, it would result in a kernel
without a valid scheduler clocksource because the Vybrid SoC lacks the
standard ARM Architected Timer hardware.

Could VF_TIMER_NONE have a depends on ARCH_S32 or !SOC_VF610 restriction to
prevent creating unbootable kernels on Vybrid?

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260513-fix-nxp-timer-v2-1-533b99c57b67@redhat.com?part=1