qualcommax: ipq807x: nbg7815: add fan and second temp sensor support

The NBG7815 cools itself with a GPIO driven fan on TLMM 21. A second
tmp103 sits on the second I2C bus (BLSP QUP4), which the stock firmware
reads as the board temperature, and the stock firmware keeps GPIO 22
high to enable the second fan.

The switching points come from the stock firmware, which controls the
fan from a shell daemon /usr/sbin/fanctld, configured in
/etc/config/fanctld:

    config fanctld config
            option Enabled  '1'
            option Delay    '20'
            option Hits     '3'
            option TempTrig '108'
            option TempClr  '85'

fanctld polls every 20 s and starts the fan once any of thermal_zone0
(nss-top), wifi0 or wifi1 has been at or above TempTrig for three
consecutive polls. It stops the fan again only after all three have been
at or below TempClr for three polls:

    if [ $temp1 -ge $temp_trig -o $temp2 -ge $temp_trig -o $temp3 -ge $temp_trig ]; then
            echo 2
    elif [ $temp1 -le $temp_clr -a $temp2 -le $temp_clr -a $temp3 -le $temp_clr ]; then
            echo 1

The trip is placed at 85 degC with 5 degC hysteresis, so the fan runs
from 85 degC and stops again at 80 degC, rather than at the stock 108/85:
the SoC hardly reaches 108, so the case gets uncomfortably hot under load
before the fan would ever start, as reported for this device in
https://github.com/openwrt/openwrt/pull/14210

It sits on the CPU cluster rather than on the sensors the stock daemon
polls: the wifi sensors are only reachable through the vendor thermaltool
there, and one zone is enough to drive the fan.

Add the gpio-fan as a cooling device with that trip, enable the second
I2C bus with its tmp103, add the gpio-hog for the second fan enable and
describe the USB VBUS switch on GPIO 32 as a regulator rather than
hogging it.

That regulator carries enable-active-high. For regulator-fixed, gpiolib
ignores the flag in the GPIO specifier and takes the line as active low
without that property, so the regulator would drive GPIO 32 low at probe
- logged as "enforce active low on GPIO handle" - while the stock
firmware holds the line high.

The AQR PHY is deliberately left out of the cooling maps: its driver
rejects the low trip the thermal core installs by default, so a thermal
zone bound to it fails to set its trips.

Co-developed-by: Semih Baskan <strst.gs@gmail.com>
Signed-off-by: Semih Baskan <strst.gs@gmail.com>
Signed-off-by: André Valentin <avalentin@marcant.net>

target/linux/qualcommax/dts/ipq8074-nbg7815.dts

@@ -43,6 +43,25 @@
 			gpios = <&tlmm 54 GPIO_ACTIVE_LOW>;
 		};
 	};
+
+	fan: fan {
+		compatible = "gpio-fan";
+		gpios = <&tlmm 21 GPIO_ACTIVE_HIGH>;
+		/* nominal rpm of the stock fan */
+		gpio-fan,speed-map = <0 0>,
+				     <3000 1>;
+		#cooling-cells = <2>;
+	};
+
+	usb_vbus: regulator-usb-vbus {
+		compatible = "regulator-fixed";
+		regulator-name = "usb_vbus";
+		regulator-min-microvolt = <5000000>;
+		regulator-max-microvolt = <5000000>;
+		gpios = <&tlmm 32 GPIO_ACTIVE_HIGH>;
+		enable-active-high;
+		regulator-boot-on;
+	};
 };
 
 &tlmm {
@@ -62,7 +81,27 @@
 		};
 	};
 
-	/* the stock firmware keeps gpio60 high to enable the LED board */
+	i2c_1_pins: i2c1-pins {
+		mux {
+			pins = "gpio50", "gpio51";
+			function = "blsp3_i2c";
+			drive-strength = <8>;
+			bias-disable;
+		};
+	};
+
+	/*
+	 * The stock firmware keeps these outputs high:
+	 * gpio22: second fan enable
+	 * gpio60: LED board enable
+	 */
+	fan2-en {
+		gpio-hog;
+		gpios = <22 GPIO_ACTIVE_HIGH>;
+		output-high;
+		line-name = "fan2-enable";
+	};
+
 	led-en {
 		gpio-hog;
 		gpios = <60 GPIO_ACTIVE_HIGH>;
@@ -728,6 +767,33 @@
 };
 
 
+/* use the second I2C bus for the second temperature sensor */
+/delete-node/ &blsp1_spi4;
+
+&soc {
+	i2c@78b8000 {
+		compatible = "qcom,i2c-qup-v2.2.1";
+		#address-cells = <1>;
+		#size-cells = <0>;
+		reg = <0x078b8000 0x600>;
+		interrupts = <GIC_SPI 98 IRQ_TYPE_LEVEL_HIGH>;
+		clocks = <&gcc GCC_BLSP1_QUP4_I2C_APPS_CLK>,
+			 <&gcc GCC_BLSP1_AHB_CLK>;
+		clock-names = "core", "iface";
+		clock-frequency = <400000>;
+		dmas = <&blsp_dma 18>, <&blsp_dma 19>;
+		dma-names = "tx", "rx";
+		pinctrl-0 = <&i2c_1_pins>;
+		pinctrl-names = "default";
+		status = "okay";
+
+		tmp103@70 {
+			compatible = "ti,tmp103";
+			reg = <0x70>;
+		};
+	};
+};
+
 &sdhc_1 {
 	status = "okay";
 	/* unstable, problem with the hs400 > h200 speed switch */
@@ -750,6 +816,7 @@
 };
 
 &qusb_phy_1 {
+	vdd-supply = <&usb_vbus>;
 	status = "okay";
 };
 
@@ -770,3 +837,27 @@
 
 	qcom,ath11k-calibration-variant = "Zyxel-NBG7815";
 };
+
+&cluster_thermal {
+	trips {
+		cluster_fan: cluster-fan {
+			/*
+			 * The stock firmware only switches the fan at 108/85
+			 * degC, which the SoC hardly ever reaches, so the case
+			 * gets uncomfortably hot under load first. Start it at
+			 * 85 degC instead, as discussed for this device in
+			 * https://github.com/openwrt/openwrt/pull/14210
+			 */
+			temperature = <85000>;
+			hysteresis = <5000>;
+			type = "active";
+		};
+	};
+
+	cooling-maps {
+		map2 {
+			trip = <&cluster_fan>;
+			cooling-device = <&fan THERMAL_NO_LIMIT THERMAL_NO_LIMIT>;
+		};
+	};
+};

target/linux/qualcommax/image/ipq807x.mk

@@ -630,7 +630,7 @@ define Device/zyxel_nbg7815
 	DEVICE_DTS_CONFIG := config@nbg7815
 	SOC := ipq8074
 	DEVICE_PACKAGES := kmod-fs-f2fs f2fs-tools ipq-wifi-zyxel_nbg7815 kmod-ath11k-pci \
-		kmod-hci-uart kmod-hwmon-tmp103 \
+		kmod-hci-uart kmod-hwmon-tmp103 kmod-hwmon-gpiofan \
 		kmod-leds-lp5569
 endef
 TARGET_DEVICES += zyxel_nbg7815