Re: [PATCH 1/5] dt-bindings: mfd: syscon: Add mt8196 fdvfs syscons

From: AngeloGioacchino Del Regno
Date: Mon Jul 14 2025 - 04:47:53 EST


Il 11/07/25 16:57, Nicolas Frattaroli ha scritto:
The MT8196 SoC uses two syscon ranges for CPU DVFS that are separate
from each other. One, mt8196-fdvfs-config, is used to check for a magic
number at that memory address to verify that fdvfs should be used. The
other, mt8196-fdvfs, is used to configure the desired frequency for the
DVFS controller for each CPU core.


What is the reason why you're using syscons here?

Can't we simply assign the FDVFS MMIO to the cpufreq-hw node?

Or is there any reason why we can't declare it as mmio-sram? ...because I'm not
entirely sure but the FDVFS space should effectively be a [c]SRAM memory range...

Cheers,
Angelo

Signed-off-by: Nicolas Frattaroli <nicolas.frattaroli@xxxxxxxxxxxxx>
---
Documentation/devicetree/bindings/mfd/syscon.yaml | 4 ++++
1 file changed, 4 insertions(+)

diff --git a/Documentation/devicetree/bindings/mfd/syscon.yaml b/Documentation/devicetree/bindings/mfd/syscon.yaml
index 27672adeb1fedb7c81b8ae86c35f4f3b26d5516f..5ee49d2ba0cdb72dd697a0fd71c8416ad4fd2c1e 100644
--- a/Documentation/devicetree/bindings/mfd/syscon.yaml
+++ b/Documentation/devicetree/bindings/mfd/syscon.yaml
@@ -88,6 +88,8 @@ select:
- mediatek,mt8135-pctl-a-syscfg
- mediatek,mt8135-pctl-b-syscfg
- mediatek,mt8173-pctl-a-syscfg
+ - mediatek,mt8196-fdvfs
+ - mediatek,mt8196-fdvfs-config
- mediatek,mt8365-syscfg
- microchip,lan966x-cpu-syscon
- microchip,mpfs-sysreg-scb
@@ -194,6 +196,8 @@ properties:
- mediatek,mt8135-pctl-a-syscfg
- mediatek,mt8135-pctl-b-syscfg
- mediatek,mt8173-pctl-a-syscfg
+ - mediatek,mt8196-fdvfs
+ - mediatek,mt8196-fdvfs-config
- mediatek,mt8365-infracfg-nao
- mediatek,mt8365-syscfg
- microchip,lan966x-cpu-syscon