[PATCH 1/3] arm64: dts: mediatek: mt8192-asurada: Add ramp-delay for MT6315 regulators

[Chen-Yu Tsai]

On Asurada, the MT6315 buck regulators (Vbcpu, Vlcpu, and Vgpu) are
missing the regulator-ramp-delay property. Without the slew rate
specified, voltage increases may not have settled before switching CPU
or GPU to higher operating points, risking undervoltage crashes.

Add regulator-ramp-delay properties matching the slew rates configured
by firmware, with values provided by MediaTek: 8000 uV/us for Vbcpu, and
4500 uV/us for Vlcpu and Vgpu.

Fixes: 3183cb62b033 ("arm64: dts: mediatek: asurada: Add SPMI regulators")
Cc: <stable at vger.kernel.org>
Signed-off-by: Chen-Yu Tsai <wenst at chromium.org>
---
Patch created with LLM. Values were translated from raw register values
by MediaTek.
---
 arch/arm64/boot/dts/mediatek/mt8192-asurada.dtsi | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/arch/arm64/boot/dts/mediatek/mt8192-asurada.dtsi b/arch/arm64/boot/dts/mediatek/mt8192-asurada.dtsi
index d1993b80f9ce..43286241cd22 100644
--- a/arch/arm64/boot/dts/mediatek/mt8192-asurada.dtsi
+++ b/arch/arm64/boot/dts/mediatek/mt8192-asurada.dtsi
@@ -1812,6 +1812,7 @@ mt6315_6_vbuck1: vbuck1 {
 				regulator-min-microvolt = <400000>;
 				regulator-max-microvolt = <1193750>;
 				regulator-enable-ramp-delay = <256>;
+				regulator-ramp-delay = <8000>;
 				regulator-allowed-modes = <0 1 2>;
 				regulator-always-on;
 			};
@@ -1821,6 +1822,7 @@ mt6315_6_vbuck3: vbuck3 {
 				regulator-min-microvolt = <400000>;
 				regulator-max-microvolt = <1193750>;
 				regulator-enable-ramp-delay = <256>;
+				regulator-ramp-delay = <4500>;
 				regulator-allowed-modes = <0 1 2>;
 				regulator-always-on;
 			};
@@ -1841,6 +1843,7 @@ mt6315_7_vbuck1: vbuck1 {
 				regulator-min-microvolt = <400000>;
 				regulator-max-microvolt = <800000>;
 				regulator-enable-ramp-delay = <256>;
+				regulator-ramp-delay = <4500>;
 				regulator-allowed-modes = <0 1 2>;
 				regulator-coupled-with = <&mt6359_vsram_others_ldo_reg>;
 				regulator-coupled-max-spread = <10000>;
-- 
2.56.0.317.g454f8302e1-goog