[PATCH 1/2] ARM: dts: rockchip: Limit GPU frequency on veyron mickey to 300 MHz when the CPU gets very hot

[Matthias Kaehlcke]

On rk3288 the CPU and GPU temperatures are correlated. Limit the GPU
frequency on veyron mickey to 300 MHz for CPU temperatures >= 85ÂC.

This matches the configuration of the downstream Chrome OS 3.14 kernel,
the 'official' kernel for mickey.

Signed-off-by: Matthias Kaehlcke <mka@xxxxxxxxxxxx>
---
Note: this patch depends on "ARM: dts: rockchip: Add #cooling-cells
entry for rk3288 GPU" (https://lore.kernel.org/patchwork/patch/1075005/)
---
 arch/arm/boot/dts/rk3288-veyron-mickey.dts | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/arch/arm/boot/dts/rk3288-veyron-mickey.dts b/arch/arm/boot/dts/rk3288-veyron-mickey.dts
index d889ab3c8235..f118d92a49d0 100644
--- a/arch/arm/boot/dts/rk3288-veyron-mickey.dts
+++ b/arch/arm/boot/dts/rk3288-veyron-mickey.dts
@@ -125,6 +125,12 @@
 					 <&cpu2 8 THERMAL_NO_LIMIT>,
 					 <&cpu3 8 THERMAL_NO_LIMIT>;
 		};
+
+		/* At very hot, don't let GPU go over 300 MHz */
+		cpu_very_hot_limit_gpu {
+			trip = <&cpu_alert_very_hot>;
+			cooling-device = <&gpu 2 2>;
+		};
 	};
 };
 
-- 
2.21.0.1020.gf2820cf01a-goog