[PATCH] ARM: dts: sun8i-h3: Add thermal trip points/cooling maps

[PATCH] ARM: dts: sun8i-h3: 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-h3.dtsi | 25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)

diff --git a/arch/arm/boot/dts/sun8i-h3.dtsi b/arch/arm/boot/dts/sun8i-h3.dtsi
index 7d2e30a00cd2a..dca51548881a8 100644
--- a/arch/arm/boot/dts/sun8i-h3.dtsi
+++ b/arch/arm/boot/dts/sun8i-h3.dtsi
@@ -41,6 +41,7 @@
  */
 
 #include "sunxi-h3-h5.dtsi"
+#include <dt-bindings/thermal/thermal.h>
 
 / {
 	cpus {
@@ -204,6 +205,30 @@ cpu_thermal: cpu-thermal {
 			polling-delay-passive = <0>;
 			polling-delay = <0>;
 			thermal-sensors = <&ths 0>;
+
+			trips {
+				cpu_hot_trip: cpu-hot {
+					temperature = <80000>;
+					hysteresis = <2000>;
+					type = "passive";
+				};
+
+				cpu_very_hot_trip: cpu-very-hot {
+					temperature = <100000>;
+					hysteresis = <0>;
+					type = "critical";
+				};
+			};
+
+			cooling-maps {
+				cpu-hot-limit {
+					trip = <&cpu_hot_trip>;
+					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>;
+				};
+			};
 		};
 	};
 };
-- 
2.25.1

Re: [PATCH] ARM: dts: sun8i-h3: Add thermal trip points/cooling maps

[Chen-Yu Tsai]

On Sun, Feb 23, 2020 at 5:42 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

> Signed-off-by: Ondrej Jirman <megous@megous.com>

Re: [PATCH] ARM: dts: sun8i-h3: Add thermal trip points/cooling maps

[Ondřej Jirman]

Hello,

On Sun, Feb 23, 2020 at 11:29:31AM +0800, Chen-Yu Tsai wrote:
> On Sun, Feb 23, 2020 at 5:42 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?

I used a slightly lowered value from the BSP code. 110 seemed like a lot for
the critical temp. So I rounded it off to 100°C.

https://megous.com/git/linux/tree/drivers/thermal/sunxi-temperature.c?h=a83t-3.4-bsp-tbs-a711#n1139

H3 lists the same recommended ambient temperature range as A83T. -20 to 70 °C.

regards,
	o.

> ChenYu
> 
> > Signed-off-by: Ondrej Jirman <megous@megous.com>