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Date: Wed, 4 Nov 2015 17:37:41 +0000
From: Javi Merino <javi.merino@....com>
To: linux-pm@...r.kernel.org
Cc: linux-kernel@...r.kernel.org, rui.zang@...el.com,
edubezval@...il.com, Javi Merino <javi.merino@....com>,
Zhang Rui <rui.zhang@...el.com>
Subject: [PATCH v2 2/3] thermal: of: parse stacked thermal zones from device tree
Let device tree set thermal zones in the thermal-sensors list of
phandles and set up the thermal zone hierarchy based on the information
present there.
Cc: Zhang Rui <rui.zhang@...el.com>
Cc: Eduardo Valentin <edubezval@...il.com>
Signed-off-by: Javi Merino <javi.merino@....com>
---
.../devicetree/bindings/thermal/thermal.txt | 154 ++++++++++++++++++++-
drivers/thermal/of-thermal.c | 99 +++++++++++++
2 files changed, 250 insertions(+), 3 deletions(-)
diff --git a/Documentation/devicetree/bindings/thermal/thermal.txt b/Documentation/devicetree/bindings/thermal/thermal.txt
index 41b817f7b670..52b7e9ae3b4d 100644
--- a/Documentation/devicetree/bindings/thermal/thermal.txt
+++ b/Documentation/devicetree/bindings/thermal/thermal.txt
@@ -145,9 +145,12 @@ Required properties:
Size: one cell
- thermal-sensors: A list of thermal sensor phandles and sensor specifier
- Type: list of used while monitoring the thermal zone.
- phandles + sensor
- specifier
+ Type: list of used while monitoring the thermal zone. The phandles
+ phandles + sensor can point to thermal sensors or other thermal zone
+ specifier nodes. If it points to other thermal zone
+ nodes you should omit the sensor specifier
+ and set #thermal-sensor-cells to 0 for the
+ thermal zone.
- trips: A sub-node which is a container of only trip point nodes
Type: sub-node required to describe the thermal zone.
@@ -603,3 +606,148 @@ thermal-zones {
The above example is a mix of previous examples, a sensor IP with several internal
sensors used to monitor different zones, one of them is composed by several sensors and
with different cooling devices.
+
+(e) Board thermal with stacked thermal zones
+
+Instead of setting up one thermal zone combining multiple thermal
+zones and multiple trip points for each cooling device, we can create
+a hierarchy of thermal zones.
+
+#include <dt-bindings/thermal/thermal.h>
+
+&i2c1 {
+ ...
+ /*
+ * An IC with several temperature sensor.
+ */
+ adc_dummy: sensor@...0 {
+ ...
+ #thermal-sensor-cells = <1>; /* sensor internal ID */
+ };
+};
+
+thermal-zones {
+
+ cpu_thermal: cpu_thermal {
+ polling-delay-passive = <1000>; /* milliseconds */
+ polling-delay = <2500>; /* milliseconds */
+
+ sustainable-power = <2500>;
+
+ thermal-sensors = <&adc_dummy 0>
+
+ trips {
+ cpu_trip: cpu-trip {
+ temperature = <60000>; /* millicelsius */
+ hysteresis = <2000>; /* millicelsius */
+ type = "passive";
+ };
+ };
+
+ cooling-maps {
+ map0 {
+ trip = <&cpu_trip>;
+ cooling-device = <&cpu0 0 2>;
+ };
+ };
+ };
+
+ gpu_thermal: gpu_thermal {
+ polling-delay-passive = <1000>; /* milliseconds */
+ polling-delay = <2500>; /* milliseconds */
+
+ sustainable-power = <2500>;
+
+ thermal-sensors = <&adc_dummy 2>
+
+ trips {
+ gpu_trip: gpu-trip {
+ temperature = <55000>; /* millicelsius */
+ hysteresis = <2000>; /* millicelsius */
+ type = "passive";
+ }
+ };
+
+ cooling-maps {
+ map0 {
+ trip = <&gpu_trip>;
+ cooling-device = <&gpu0 0 2>;
+ };
+ };
+ };
+
+ lcd_thermal: lcd_thermal {
+ polling-delay-passive = <1000>; /* milliseconds */
+ polling-delay = <2500>; /* milliseconds */
+
+ sustainable-power = <2500>;
+
+ thermal-sensors = <&adc_dummy 1>
+
+ trips {
+ lcd_trip: lcp-trip {
+ temperature = <53000>; /* millicelsius */
+ hysteresis = <2000>; /* millicelsius */
+ type = "passive";
+ };
+ };
+
+ cooling-maps {
+ map0 {
+ trip = <&lcd_trip>;
+ cooling-device = <&lcd0 5 10>;
+ };
+ };
+ };
+
+ board_thermal: board-thermal {
+ polling-delay-passive = <1000>; /* milliseconds */
+ polling-delay = <2500>; /* milliseconds */
+
+ thermal-sensors = <&cpu_thermal &gpu_thermal &lcd_thermal>
+
+ sustainable-power = <2500>;
+
+ trips {
+ warm_trip: warm-trip {
+ temperature = <62000>; /* millicelsius */
+ hysteresis = <2000>; /* millicelsius */
+ type = "passive";
+ };
+ crit_trip: crit-trip {
+ temperature = <68000>; /* millicelsius */
+ hysteresis = <2000>; /* millicelsius */
+ type = "critical";
+ };
+ };
+
+ cooling-maps {
+ map0 {
+ trip = <&warm_trip>;
+ cooling-device = <&cpu0 2 2>;
+ contribution = <55>;
+ };
+ map1 {
+ trip = <&warm_trip>;
+ cooling-device = <&gpu0 2 2>;
+ contribution = <20>;
+ };
+ map2 {
+ trip = <&lcd_trip>;
+ cooling-device = <&lcd0 7 10>;
+ contribution = <15>;
+ };
+ };
+ };
+};
+
+The above example is a different take at example (d). We create one
+thermal zone per sensor: cpu_thermal, gpu_thermal and lcd_thermal.
+Each of which has its own trip point for each own cooling device. We
+then define a board_thermal thermal zone that is a combination of all
+the other thermal zones. If the board hits its warm_trip, then all
+cooling devices are throttled.
+
+This example illustrates how we can throttle each device individually
+if its too hot and at the same time have some control over the whole
+system.
diff --git a/drivers/thermal/of-thermal.c b/drivers/thermal/of-thermal.c
index 42b7d4253b94..17e8ae5edd73 100644
--- a/drivers/thermal/of-thermal.c
+++ b/drivers/thermal/of-thermal.c
@@ -166,6 +166,27 @@ of_thermal_get_trip_points(struct thermal_zone_device *tz)
EXPORT_SYMBOL_GPL(of_thermal_get_trip_points);
/**
+ * of_thermal_is_thermal_zone - check that a device node corresponds to a thermal zone
+ * @np: the device node
+ *
+ * Valid thermal zone device nodes must provide the
+ * polling-delay-passive and polling-delay properties. This function
+ * checks if @np is thermal-zone node.
+ *
+ * Return: true if @np is a valid device for a thermal zone.
+ */
+static bool of_thermal_is_thermal_zone(struct device_node *np)
+{
+ u32 out;
+
+ if ((of_property_read_u32(np, "polling-delay-passive", &out)) ||
+ (of_property_read_u32(np, "polling-delay", &out)))
+ return false;
+
+ return true;
+}
+
+/**
* of_thermal_set_emul_temp - function to set emulated temperature
*
* @tz: pointer to a thermal zone
@@ -858,6 +879,81 @@ static inline void of_thermal_free_zone(struct __thermal_zone *tz)
}
/**
+ * link_stacked_thermal_zones - link thermal zones that are a superset of thermal zones
+ * @np: device node for the root of the thermal zones
+ *
+ * A thermal zone can specify other thermal zones as its input using
+ * the thermal-sensors property of device tree. This function parses
+ * all the thermal zones in dt and adds the thermal zones in their
+ * thermal-sensors as sub-thermalzones.
+ */
+static void link_stacked_thermal_zones(struct device_node *np)
+{
+ struct device_node *child;
+
+ for_each_child_of_node(np, child) {
+ int i, num_sensors;
+ struct thermal_zone_device *tz;
+
+ num_sensors = of_count_phandle_with_args(child,
+ "thermal-sensors",
+ "#thermal-sensor-cells");
+ if (num_sensors <= 0)
+ continue;
+
+ tz = thermal_zone_get_zone_by_name(child->name);
+ if (IS_ERR_OR_NULL(tz)) {
+ /*
+ * If the tz is available we should have added
+ * it in of_parse_thermal_zones()
+ */
+ WARN(of_device_is_available(child),
+ "Couldn't find thermal zone for %s\n",
+ of_node_full_name(child));
+ continue;
+ }
+
+ for (i = 0; i < num_sensors; i++) {
+ struct of_phandle_args sensor_specs;
+ struct thermal_zone_device *subtz;
+ int ret;
+
+ ret = of_parse_phandle_with_args(child,
+ "thermal-sensors",
+ "#thermal-sensor-cells",
+ i, &sensor_specs);
+ if (ret) {
+ pr_warn("Failed to parse thermal-sensors of %s: %d\n",
+ of_node_full_name(child), ret);
+ of_node_put(sensor_specs.np);
+ continue;
+ }
+
+ if (!of_thermal_is_thermal_zone(sensor_specs.np)) {
+ of_node_put(sensor_specs.np);
+ continue;
+ }
+
+ subtz = thermal_zone_get_zone_by_name(
+ sensor_specs.np->name);
+ if (IS_ERR_OR_NULL(subtz)) {
+ pr_warn("Couldn't find thermal zone for %s, is it disabled?\n",
+ of_node_full_name(sensor_specs.np));
+ of_node_put(sensor_specs.np);
+ continue;
+ }
+
+ ret = thermal_zone_add_subtz(tz, subtz);
+ if (ret)
+ pr_warn("Failed to add thermal zone %s to %s: %d\n",
+ subtz->type, tz->type, ret);
+
+ of_node_put(sensor_specs.np);
+ }
+ }
+}
+
+/**
* of_parse_thermal_zones - parse device tree thermal data
*
* Initialization function that can be called by machine initialization
@@ -936,6 +1032,9 @@ int __init of_parse_thermal_zones(void)
/* attempting to build remaining zones still */
}
}
+
+ link_stacked_thermal_zones(np);
+
of_node_put(np);
return 0;
--
1.9.1
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