[PATCH v3] arm64: dts: renesas: r8a779g3: Update thermal trip points on V4H Sparrow Hawk

[PATCH v3] 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.

Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Signed-off-by: Marek Vasut <marek.vasut+renesas@mailbox.org>
---
Cc: Conor Dooley <conor+dt@kernel.org>
Cc: Geert Uytterhoeven <geert+renesas@glider.be>
Cc: Krzysztof Kozlowski <krzk+dt@kernel.org>
Cc: Magnus Damm <magnus.damm@gmail.com>
Cc: "Niklas Söderlund" <niklas.soderlund@ragnatech.se>
Cc: Rob Herring <robh@kernel.org>
Cc: devicetree@vger.kernel.org
Cc: linux-renesas-soc@vger.kernel.org
---
V2: Add RB from Niklas
V3: - Sort DT nodes
    - Update comment on idle states, note the 0..80%
    - Add RB from Geert
---
 .../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 1f44005e1a11..75b1b789ae1d 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"
 
@@ -189,6 +190,41 @@ vcc_sdhi: regulator-vcc-sdhi {
 	};
 };
 
+/* Use 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>;
+	};
+};
+
 &audio_clkin {
 	clock-frequency = <24576000>;
 };
@@ -801,3 +837,104 @@ &rwdt {
 &scif_clk {	/* X12 */
 	clock-frequency = <24000000>;
 };
+
+/* 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>;
+};
+
+/* 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 0..80% of time */
+			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_cnn {
+	critical-action = "shutdown";
+};
+
+&sensor_thermal_cr52 {
+	critical-action = "shutdown";
+};
+
+&sensor_thermal_ddr1 {
+	critical-action = "shutdown";
+};
-- 
2.47.2

Re: [PATCH v3] arm64: dts: renesas: r8a779g3: Update thermal trip points on V4H Sparrow Hawk

[Geert Uytterhoeven]

On Fri, 15 Aug 2025 at 01:35, Marek Vasut
<marek.vasut+renesas@mailbox.org> wrote:
> 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.
>
> Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
> Reviewed-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
> Signed-off-by: Marek Vasut <marek.vasut+renesas@mailbox.org>
> ---
> Cc: Conor Dooley <conor+dt@kernel.org>
> Cc: Geert Uytterhoeven <geert+renesas@glider.be>
> Cc: Krzysztof Kozlowski <krzk+dt@kernel.org>
> Cc: Magnus Damm <magnus.damm@gmail.com>
> Cc: "Niklas Söderlund" <niklas.soderlund@ragnatech.se>
> Cc: Rob Herring <robh@kernel.org>
> Cc: devicetree@vger.kernel.org
> Cc: linux-renesas-soc@vger.kernel.org
> ---
> V2: Add RB from Niklas
> V3: - Sort DT nodes
>     - Update comment on idle states, note the 0..80%
>     - Add RB from Geert

Thanks, will queue in renesas-devel for v6.18.

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds

Re: [PATCH v3] arm64: dts: renesas: r8a779g3: Update thermal trip points on V4H Sparrow Hawk

[Geert Uytterhoeven]

On Mon, 18 Aug 2025 at 08:48, Geert Uytterhoeven <geert@linux-m68k.org> wrote:
> On Fri, 15 Aug 2025 at 01:35, Marek Vasut
> <marek.vasut+renesas@mailbox.org> wrote:
> > 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.
> >
> > Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
> > Reviewed-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
> > Signed-off-by: Marek Vasut <marek.vasut+renesas@mailbox.org>
> > ---
> > Cc: Conor Dooley <conor+dt@kernel.org>
> > Cc: Geert Uytterhoeven <geert+renesas@glider.be>
> > Cc: Krzysztof Kozlowski <krzk+dt@kernel.org>
> > Cc: Magnus Damm <magnus.damm@gmail.com>
> > Cc: "Niklas Söderlund" <niklas.soderlund@ragnatech.se>
> > Cc: Rob Herring <robh@kernel.org>
> > Cc: devicetree@vger.kernel.org
> > Cc: linux-renesas-soc@vger.kernel.org
> > ---
> > V2: Add RB from Niklas
> > V3: - Sort DT nodes
> >     - Update comment on idle states, note the 0..80%
> >     - Add RB from Geert
>
> Thanks, will queue in renesas-devel for v6.18.

With s/r8a779g3: Update thermal trip points on V4H Sparrow
Hawk/sparrow-hawk: Update thermal trip points/.

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds