[PATCH] ARM: dts: sun8i-a83t: Add thermal trip points/cooling maps

[PATCH] ARM: dts: sun8i-a83t: Add thermal trip points/cooling maps

[Ondrej Jirman]

This enables passive cooling by down-regulating CPU voltage
and frequency.

Signed-off-by: Ondrej Jirman <megous@megous.com>
---
 arch/arm/boot/dts/sun8i-a83t.dtsi | 60 +++++++++++++++++++++++++++----
 1 file changed, 54 insertions(+), 6 deletions(-)

diff --git a/arch/arm/boot/dts/sun8i-a83t.dtsi b/arch/arm/boot/dts/sun8i-a83t.dtsi
index 74ac7ee9383cf..53c2b6a836f27 100644
--- a/arch/arm/boot/dts/sun8i-a83t.dtsi
+++ b/arch/arm/boot/dts/sun8i-a83t.dtsi
@@ -72,7 +72,7 @@ cpu0: cpu@0 {
 			#cooling-cells = <2>;
 		};
 
-		cpu@1 {
+		cpu1: cpu@1 {
 			compatible = "arm,cortex-a7";
 			device_type = "cpu";
 			clocks = <&ccu CLK_C0CPUX>;
@@ -83,7 +83,7 @@ cpu@1 {
 			#cooling-cells = <2>;
 		};
 
-		cpu@2 {
+		cpu2: cpu@2 {
 			compatible = "arm,cortex-a7";
 			device_type = "cpu";
 			clocks = <&ccu CLK_C0CPUX>;
@@ -94,7 +94,7 @@ cpu@2 {
 			#cooling-cells = <2>;
 		};
 
-		cpu@3 {
+		cpu3: cpu@3 {
 			compatible = "arm,cortex-a7";
 			device_type = "cpu";
 			clocks = <&ccu CLK_C0CPUX>;
@@ -116,7 +116,7 @@ cpu100: cpu@100 {
 			#cooling-cells = <2>;
 		};
 
-		cpu@101 {
+		cpu101: cpu@101 {
 			compatible = "arm,cortex-a7";
 			device_type = "cpu";
 			clocks = <&ccu CLK_C1CPUX>;
@@ -127,7 +127,7 @@ cpu@101 {
 			#cooling-cells = <2>;
 		};
 
-		cpu@102 {
+		cpu102: cpu@102 {
 			compatible = "arm,cortex-a7";
 			device_type = "cpu";
 			clocks = <&ccu CLK_C1CPUX>;
@@ -138,7 +138,7 @@ cpu@102 {
 			#cooling-cells = <2>;
 		};
 
-		cpu@103 {
+		cpu103: cpu@103 {
 			compatible = "arm,cortex-a7";
 			device_type = "cpu";
 			clocks = <&ccu CLK_C1CPUX>;
@@ -1188,12 +1188,60 @@ cpu0_thermal: cpu0-thermal {
 			polling-delay-passive = <0>;
 			polling-delay = <0>;
 			thermal-sensors = <&ths 0>;
+
+			trips {
+				cpu0_hot: cpu-hot {
+					temperature = <80000>;
+					hysteresis = <2000>;
+					type = "passive";
+				};
+
+				cpu0_very_hot: cpu-very-hot {
+					temperature = <100000>;
+					hysteresis = <0>;
+					type = "critical";
+				};
+			};
+
+			cooling-maps {
+				cpu-hot-limit {
+					trip = <&cpu0_hot>;
+					cooling-device = <&cpu0 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>,
+							 <&cpu1 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>,
+							 <&cpu2 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>,
+							 <&cpu3 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>;
+				};
+			};
 		};
 
 		cpu1_thermal: cpu1-thermal {
 			polling-delay-passive = <0>;
 			polling-delay = <0>;
 			thermal-sensors = <&ths 1>;
+
+			trips {
+				cpu1_hot: cpu-hot {
+					temperature = <80000>;
+					hysteresis = <2000>;
+					type = "passive";
+				};
+
+				cpu1_very_hot: cpu-very-hot {
+					temperature = <100000>;
+					hysteresis = <0>;
+					type = "critical";
+				};
+			};
+
+			cooling-maps {
+				cpu-hot-limit {
+					trip = <&cpu1_hot>;
+					cooling-device = <&cpu100 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>,
+							 <&cpu101 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>,
+							 <&cpu102 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>,
+							 <&cpu103 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>;
+				};
+			};
 		};
 
 		gpu_thermal: gpu-thermal {
-- 
2.25.1

Re: [PATCH] ARM: dts: sun8i-a83t: Add thermal trip points/cooling maps

[Chen-Yu Tsai]

Hi,

On Sun, Feb 23, 2020 at 5:40 AM Ondrej Jirman <megous@megous.com> wrote:
>
> This enables passive cooling by down-regulating CPU voltage
> and frequency.

Please state for the record how the trip points were derived. Were they from
the BSP? Or the user manual?

ChenYu

Re: [PATCH] ARM: dts: sun8i-a83t: Add thermal trip points/cooling maps

[Ondřej Jirman]

Hello,

On Sun, Feb 23, 2020 at 11:29:07AM +0800, Chen-Yu Tsai wrote:
> Hi,
> 
> On Sun, Feb 23, 2020 at 5:40 AM Ondrej Jirman <megous@megous.com> wrote:
> >
> > This enables passive cooling by down-regulating CPU voltage
> > and frequency.
> 
> Please state for the record how the trip points were derived. Were they from
> the BSP? Or the user manual?

The values are taken from the BSP for A83T:

https://megous.com/git/linux/tree/drivers/thermal/sunxi-temperature.c?h=a83t-3.4-bsp-tbs-a711#n747

The datasheet only mentions recommended Ta (ambient operating temperature) range
-20 to +70°C. So die voltages will be larger than that. I guess that roughly
matches the BSP values.

regards,
	o.

> ChenYu

Re: [PATCH] ARM: dts: sun8i-a83t: Add thermal trip points/cooling maps

[Maxime Ripard]

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On Sun, Feb 23, 2020 at 11:10:50AM +0100, Ondřej Jirman wrote:
> Hello,
>
> On Sun, Feb 23, 2020 at 11:29:07AM +0800, Chen-Yu Tsai wrote:
> > Hi,
> >
> > On Sun, Feb 23, 2020 at 5:40 AM Ondrej Jirman <megous@megous.com> wrote:
> > >
> > > This enables passive cooling by down-regulating CPU voltage
> > > and frequency.
> >
> > Please state for the record how the trip points were derived. Were they from
> > the BSP? Or the user manual?
>
> The values are taken from the BSP for A83T:
>
> https://megous.com/git/linux/tree/drivers/thermal/sunxi-temperature.c?h=a83t-3.4-bsp-tbs-a711#n747
>
> The datasheet only mentions recommended Ta (ambient operating temperature) range
> -20 to +70°C. So die voltages will be larger than that. I guess that roughly
> matches the BSP values.

Can you put that in the commit log?

Thanks!
Maxime

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