[PATCH] arm64: dts: renesas: r8a779g3: Update thermal trip points on V4H Sparrow Hawk

[Marek Vasut]

Since the Sparrow Hawk has a smaller PCB than the White Hawk, it tends
to generate more heat. To prevent potential damage to the board, adjust
the temperature trip points.

Add four "passive" trip points which increasingly throttle the CPU to
prevent overheating. The first trip point at 68°C disables the 1.8 GHz
and 1.7 GHz modes and limits the CPU to 1.5 GHz frequency. The second
trip point at 72°C disables the 1.5 GHz mode and limits the CPU to 1.0
GHz frequency. The third trip point at 76°C uses thermal-idle to start
inserting idle cycles into the CPU instruction stream to cool the CPU
cores down. The fourth and last trip point at 80°C disables the 1.0 GHz
mode and limits the CPU to 500 MHz frequency.

In case the SoC heats up further, in case either of the thermal sensors
readings passes the 100°C, a thermal shutdown is triggered to prevent
any damage to the hardware.

Signed-off-by: Marek Vasut <marek.vasut+renesas at mailbox.org>
---
Cc: Conor Dooley <conor+dt at kernel.org>
Cc: Geert Uytterhoeven <geert+renesas at glider.be>
Cc: Krzysztof Kozlowski <krzk+dt at kernel.org>
Cc: Magnus Damm <magnus.damm at gmail.com>
Cc: "Niklas Söderlund" <niklas.soderlund at ragnatech.se>
Cc: Rob Herring <robh at kernel.org>
Cc: devicetree at vger.kernel.org
Cc: linux-renesas-soc at vger.kernel.org
---
 .../dts/renesas/r8a779g3-sparrow-hawk.dts     | 137 ++++++++++++++++++
 1 file changed, 137 insertions(+)

diff --git a/arch/arm64/boot/dts/renesas/r8a779g3-sparrow-hawk.dts b/arch/arm64/boot/dts/renesas/r8a779g3-sparrow-hawk.dts
index 9ba23129e65e..ba81df3c779d 100644
--- a/arch/arm64/boot/dts/renesas/r8a779g3-sparrow-hawk.dts
+++ b/arch/arm64/boot/dts/renesas/r8a779g3-sparrow-hawk.dts
@@ -38,6 +38,7 @@
 
 /dts-v1/;
 #include <dt-bindings/gpio/gpio.h>
+#include <dt-bindings/thermal/thermal.h>
 
 #include "r8a779g3.dtsi"
 
@@ -797,3 +798,139 @@ &rwdt {
 &scif_clk {	/* X12 */
 	clock-frequency = <24000000>;
 };
+
+/* thermal-idle cooling for all SoC cores */
+&a76_0 {
+	#cooling-cells = <2>;
+
+	a76_0_thermal_idle: thermal-idle {
+		#cooling-cells = <2>;
+		duration-us = <10000>;
+		exit-latency-us = <500>;
+	};
+};
+
+&a76_1 {
+	a76_1_thermal_idle: thermal-idle {
+		#cooling-cells = <2>;
+		duration-us = <10000>;
+		exit-latency-us = <500>;
+	};
+};
+
+&a76_2 {
+	a76_2_thermal_idle: thermal-idle {
+		#cooling-cells = <2>;
+		duration-us = <10000>;
+		exit-latency-us = <500>;
+	};
+};
+
+&a76_3 {
+	a76_3_thermal_idle: thermal-idle {
+		#cooling-cells = <2>;
+		duration-us = <10000>;
+		exit-latency-us = <500>;
+	};
+};
+
+/* THS sensors in SoC, critical temperature trip point is 100C */
+&sensor1_crit {
+	temperature = <100000>;
+};
+
+&sensor2_crit {
+	temperature = <100000>;
+};
+
+&sensor3_crit {
+	temperature = <100000>;
+};
+
+&sensor4_crit {
+	temperature = <100000>;
+};
+
+&sensor_thermal_cr52 {
+	critical-action = "shutdown";
+};
+
+&sensor_thermal_cnn {
+	critical-action = "shutdown";
+};
+
+/* THS sensor in SoC near CA76 cores does more progressive cooling. */
+&sensor_thermal_ca76 {
+	critical-action = "shutdown";
+
+	cooling-maps {
+		/*
+		 * The cooling-device minimum and maximum parameters inversely
+		 * match opp-table-0 {} node entries in r8a779g0.dtsi, in other
+		 * words, 0 refers to 1.8 GHz OPP and 4 refers to 500 MHz OPP.
+		 * This is because they refer to cooling levels, where maximum
+		 * cooling level happens at 500 MHz OPP, when the CPU core is
+		 * running slowly and therefore generates least heat.
+		 */
+		map0 {
+			/* At 68C, inhibit 1.7 GHz and 1.8 GHz modes */
+			trip = <&sensor3_passive_low>;
+			cooling-device = <&a76_0 2 4>;
+			contribution = <128>;
+		};
+
+		map1 {
+			/* At 72C, inhibit 1.5 GHz mode */
+			trip = <&sensor3_passive_mid>;
+			cooling-device = <&a76_0 3 4>;
+			contribution = <256>;
+		};
+
+		map2 {
+			/* At 76C, start injecting idle states */
+			trip = <&sensor3_passive_hi>;
+			cooling-device = <&a76_0_thermal_idle 0 80>,
+					 <&a76_1_thermal_idle 0 80>,
+					 <&a76_2_thermal_idle 0 80>,
+					 <&a76_3_thermal_idle 0 80>;
+			contribution = <512>;
+		};
+
+		map3 {
+			/* At 80C, inhibit 1.0 GHz mode */
+			trip = <&sensor3_passive_crit>;
+			cooling-device = <&a76_0 4 4>;
+			contribution = <1024>;
+		};
+	};
+
+	trips {
+		sensor3_passive_low: sensor3-passive-low {
+			temperature = <68000>;
+			hysteresis = <2000>;
+			type = "passive";
+		};
+
+		sensor3_passive_mid: sensor3-passive-mid {
+			temperature = <72000>;
+			hysteresis = <2000>;
+			type = "passive";
+		};
+
+		sensor3_passive_hi: sensor3-passive-hi {
+			temperature = <76000>;
+			hysteresis = <2000>;
+			type = "passive";
+		};
+
+		sensor3_passive_crit: sensor3-passive-crit {
+			temperature = <80000>;
+			hysteresis = <2000>;
+			type = "passive";
+		};
+	};
+};
+
+&sensor_thermal_ddr1 {
+	critical-action = "shutdown";
+};
-- 
2.47.2