meson-64: Expose Amlogic thermal as HWMON devices (#2586)

- this lets lm-sensors see the ddr/cpu temps, on HC4 at least

Signed-off-by: Ricardo Pardini <ricardo@pardini.net>

patch/kernel/meson64-current/thermal_amlogic_thermal_add_hwmon_support.patch

@@ -0,0 +1,44 @@
+From 719854edeb7c2c85901031f3062e89fafa66ea1b Mon Sep 17 00:00:00 2001
+From: Dongjin Kim <tobetter@gmail.com>
+Date: Wed, 25 Nov 2020 03:43:28 +0900
+Subject: [PATCH] thermal: amlogic_thermal: Add hwmon support
+
+Expose Amlogic thermal as HWMON devices.
+
+	$ sensors
+	cpu_thermal-virtual-0
+	Adapter: Virtual device
+	temp1:        +32.2 C  (crit = +110.0 C)
+
+	ddr_thermal-virtual-0
+	Adapter: Virtual device
+	temp1:        +33.4 C  (crit = +110.0 C)
+
+Signed-off-by: Dongjin Kim <tobetter@gmail.com>
+Change-Id: Icb1bf7cd7e4462f9923af5bcd72fa7c0c8e14cc9
+---
+ drivers/thermal/amlogic_thermal.c | 4 ++++
+ 1 file changed, 4 insertions(+)
+
+diff --git a/drivers/thermal/amlogic_thermal.c b/drivers/thermal/amlogic_thermal.c
+index ccb1fe18e9931..2fce96c32586f 100644
+--- a/drivers/thermal/amlogic_thermal.c
++++ b/drivers/thermal/amlogic_thermal.c
+@@ -29,6 +29,7 @@
+ #include <linux/thermal.h>
+
+ #include "thermal_core.h"
++#include "thermal_hwmon.h"
+
+ #define TSENSOR_CFG_REG1			0x4
+ 	#define TSENSOR_CFG_REG1_RSET_VBG	BIT(12)
+@@ -291,6 +292,9 @@ static int amlogic_thermal_probe(struct platform_device *pdev)
+ 	if (ret)
+ 		return ret;
+
++	if (devm_thermal_add_hwmon_sysfs(pdata->tzd))
++		dev_warn(&pdev->dev, "failed to add hwmon sysfs attributes\n");
++
+ 	ret = amlogic_thermal_enable(pdata);
+
+ 	return ret;