From 2b2e9d0e1ee4765b21c648235489028c6dc7e336 Mon Sep 17 00:00:00 2001
From: Linus Walleij <linus.walleij@linaro.org>
Date: Tue, 31 Dec 2019 18:18:08 +0100
Subject: [PATCH 4/7] ARM: dts: gemini: Add thermal zone to DIR-685

The DIR-685 can now exploit the thermal zone added by the
drive temperature sensor inside the hard drive. We have
patched the libata subsystem to assign the device nodes
properly to the SCSI devices and this is what the drivetemp
driver will use to populate the sensor and the thermal
zone, so pick that up into the thermal zone and let this
control the fan.

The hardware lacks an embedded temperature sensor so the
D-Link vendor firmware uses this method to control the
temperature of the NAS enclosure using the thermal sensor
inside the hard drive.

The drive temperature trigger points to be used comes from
the vendor firmware.

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
---
 arch/arm/boot/dts/gemini-dlink-dir-685.dts | 48 ++++++++++++++++++++--
 1 file changed, 45 insertions(+), 3 deletions(-)

--- a/arch/arm/boot/dts/gemini-dlink-dir-685.dts
+++ b/arch/arm/boot/dts/gemini-dlink-dir-685.dts
@@ -119,13 +119,11 @@
 
 	/*
 	 * This is a Sunon Maglev GM0502PFV2-8 cooling fan @10000 RPM.
-	 * Since the platform has no temperature sensor, this is controlled
-	 * from userspace by using the hard disks S.M.A.R.T. temperature
 	 * sensor. It is turned on when the temperature exceeds 46 degrees
 	 * and turned off when the temperatures goes below 41 degrees
 	 * (celsius).
 	 */
-	gpio-fan {
+	fan0: gpio-fan {
 		compatible = "gpio-fan";
 		/* Collides with IDE */
 		gpios = <&gpio1 6 GPIO_ACTIVE_HIGH>;
@@ -133,6 +131,40 @@
 		#cooling-cells = <2>;
 	};
 
+	thermal-zones {
+		chassis-thermal {
+			/* Poll every 20 seconds */
+			polling-delay = <20000>;
+			/* Poll every 2nd second when cooling */
+			polling-delay-passive = <2000>;
+			/*  Use the thermal sensor in the hard drive */
+			thermal-sensors = <&drive0>;
+
+			/* Tripping points from the fan.script in the rootfs */
+			trips {
+				alert: chassis-alert {
+					/* At 43 degrees turn on the fan */
+					temperature = <43000>;
+					hysteresis = <3000>;
+					type = "active";
+				};
+				crit: chassis-crit {
+					/* Just shut down at 60 degrees */
+					temperature = <60000>;
+					hysteresis = <2000>;
+					type = "critical";
+				};
+			};
+
+			cooling-maps {
+				map0 {
+					trip = <&alert>;
+					cooling-device = <&fan0 1 1>;
+				};
+			};
+		};
+	};
+
 	/*
 	 * The touchpad input is connected to a GPIO bit-banged
 	 * I2C bus.
@@ -445,6 +477,16 @@
 
 		ide@63000000 {
 			status = "okay";
+
+			/*
+			 * This drive may have a temperature sensor with a
+			 * thermal zone we can use for thermal control of the
+			 * chassis temperature using the fan.
+			 */
+			drive0: ide-port@0 {
+				reg = <0>;
+				#thermal-sensor-cells = <0>;
+			};
 		};
 
 		display-controller@6a000000 {