17.12.2020 21:28, Daniel Lezcano пишет:

On 17/12/2020 19:06, Dmitry Osipenko wrote:

quoted

Enable CPU voltage scaling and thermal throttling on Tegra20 Ventana board.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 arch/arm/boot/dts/tegra20-ventana.dts | 40 ++++++++++++++++++++++++++-
 1 file changed, 39 insertions(+), 1 deletion(-)

diff --git a/arch/arm/boot/dts/tegra20-ventana.dts b/arch/arm/boot/dts/tegra20-ventana.dts
index 14ace2ef749c..c2d9f38960bc 100644
--- a/arch/arm/boot/dts/tegra20-ventana.dts
+++ b/arch/arm/boot/dts/tegra20-ventana.dts

@@ -2,8 +2,10 @@
 /dts-v1/;
 
 #include <dt-bindings/input/input.h>
+#include <dt-bindings/thermal/thermal.h>
 #include "tegra20.dtsi"
 #include "tegra20-cpu-opp.dtsi"
+#include "tegra20-cpu-opp-microvolt.dtsi"
 
 / {
 	model = "NVIDIA Tegra20 Ventana evaluation board";

@@ -527,9 +529,10 @@ ldo_rtc {
 			};
 		};
 
-		temperature-sensor@4c {
+		nct1008: temperature-sensor@4c {
 			compatible = "onnn,nct1008";
 			reg = <0x4c>;
+			#thermal-sensor-cells = <1>;
 		};
 	};
 

@@ -615,10 +618,13 @@ clk32k_in: clock@0 {
 
 	cpus {
 		cpu0: cpu@0 {
+			cpu-supply = <&vdd_cpu>;
 			operating-points-v2 = <&cpu0_opp_table>;
+			#cooling-cells = <2>;
 		};
 
 		cpu@1 {
+			cpu-supply = <&vdd_cpu>;
 			operating-points-v2 = <&cpu0_opp_table>;
 		};
 	};

@@ -717,4 +723,36 @@ sound {
 			 <&tegra_car TEGRA20_CLK_CDEV1>;
 		clock-names = "pll_a", "pll_a_out0", "mclk";
 	};
+
+	thermal-zones {
+		cpu-thermal {
+			polling-delay-passive = <1000>; /* milliseconds */
+			polling-delay = <5000>; /* milliseconds */
+
+			thermal-sensors = <&nct1008 1>;
+
+			trips {
+				trip0: cpu-alert0 {
+					/* start throttling at 50C */
+					temperature = <50000>;
+					hysteresis = <200>;

Did you mean <2000> ?

The <200> is correct.

Please see this commit for example:

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=2b22393b27670b45a2c870bce3df6579efd9a86a

quoted

+					type = "passive";
+				};
+
+				trip1: cpu-crit {
+					/* shut down at 60C */
+					temperature = <60000>;
+					hysteresis = <2000>;

I think you can drop the hysteresis here, when the critical temperature
is reached, there is an emergency shutdown.

Yes, perhaps you're right. Hysteresis doesn't make sense for a critical
trip. I'll improve it in the next revision, thanks.

50°C and 60°C sound very low values, no ?

Tegra20 CPU is very cold in comparison to later generations, it should
stay under 50°C even at a full load.

quoted

+					type = "critical";
+				};
+			};
+
+			cooling-maps {
+				map0 {
+					trip = <&trip0>;
+					cooling-device = <&cpu0 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>;

You should add all CPUs here.

All CPU cores are coupled on Tegra in regards to CPUFreq, hence I think
it won't make any difference if secondary CPU cores will be added here,
isn't it?