[PATCH v2 7/7] thermal: export thermal_zone_parameters to sysfs

Javi Merino
2015-02-26T19:00:33Z

It's useful for tuning to be able to edit thermal_zone_parameters from
userspace. Export them to the thermal_zone sysfs so that they can be
easily changed.

Cc: Zhang Rui <rui.zhang@intel.com>
Cc: Eduardo Valentin <edubezval@gmail.com>
Signed-off-by: Javi Merino <javi.merino@arm.com>
---
Documentation/thermal/sysfs-api.txt | 52 +++++++++++++++++
drivers/thermal/thermal_core.c | 110 ++++++++++++++++++++++++++++++++++++
2 files changed, 162 insertions(+)

diff --git a/Documentation/thermal/sysfs-api.txt b/Documentation/thermal/sysfs-api.txt
index fc7dfe10778b..7d44d7f1a71b 100644
--- a/Documentation/thermal/sysfs-api.txt
+++ b/Documentation/thermal/sysfs-api.txt
@@ -184,6 +184,12 @@ Thermal zone device sys I/F, created once it's registered:
|---trip_point_[0-*]_type: Trip point type
|---trip_point_[0-*]_hyst: Hysteresis value for this trip point
|---emul_temp: Emulated temperature set node
+ |---sustainable_power: Sustainable dissipatable power
+ |---k_po: Proportional term during temperature overshoot
+ |---k_pu: Proportional term during temperature undershoot
+ |---k_i: PID's integral term in the power allocator gov
+ |---k_d: PID's derivative term in the power allocator
+ |---integral_cutoff: Offset above which errors are accumulated

Thermal cooling device sys I/F, created once it's registered:
/sys/class/thermal/cooling_device[0-*]:
@@ -307,6 +313,52 @@ emul_temp
because userland can easily disable the thermal policy by simply
flooding this sysfs node with low temperature values.

+sustainable_power
+ An estimate of the sustained power that can be dissipated by
+ the thermal zone. Used by the power allocator governor. For
+ more information see Documentation/thermal/power_allocator.txt
+ Unit: milliwatts
+ RW, Optional
+
+k_po
+ The proportional term of the power allocator governor's PID
+ controller during temperature overshoot. Temperature overshoot
+ is when the current temperature is above the "desired
+ temperature" trip point. For more information see
+ Documentation/thermal/power_allocator.txt
+ RW, Optional
+
+k_pu
+ The proportional term of the power allocator governor's PID
+ controller during temperature undershoot. Temperature undershoot
+ is when the current temperature is below the "desired
+ temperature" trip point. For more information see
+ Documentation/thermal/power_allocator.txt
+ RW, Optional
+
+k_i
+ The integral term of the power allocator governor's PID
+ controller. This term allows the PID controller to compensate
+ for long term drift. For more information see
+ Documentation/thermal/power_allocator.txt
+ RW, Optional
+
+k_d
+ The derivative term of the power allocator governor's PID
+ controller. For more information see
+ Documentation/thermal/power_allocator.txt
+ RW, Optional
+
+integral_cutoff
+ Temperature offset from the desired temperature trip point
+ above which the integral term of the power allocator
+ governor's PID controller starts accumulating errors. For
+ example, if integral_cutoff is 0, then the integral term only
+ accumulates error when temperature is above the desired
+ temperature trip point. For more information see
+ Documentation/thermal/power_allocator.txt
+ RW, Optional
+
*****************************
* Cooling device attributes *
*****************************
diff --git a/drivers/thermal/thermal_core.c b/drivers/thermal/thermal_core.c
index df9ba3bf55dc..228e93f8a146 100644
--- a/drivers/thermal/thermal_core.c
+++ b/drivers/thermal/thermal_core.c
@@ -873,6 +873,111 @@ emul_temp_store(struct device *dev, struct device_attribute *attr,
static DEVICE_ATTR(emul_temp, S_IWUSR, NULL, emul_temp_store);
#endif/*CONFIG_THERMAL_EMULATION*/

+#ifdef CONFIG_THERMAL_GOV_POWER_ALLOCATOR
+
+static ssize_t
+sustainable_power_show(struct device *dev, struct device_attribute *devattr,
+ char *buf)
+{
+ struct thermal_zone_device *tz = to_thermal_zone(dev);
+
+ if (tz->tzp)
+ return sprintf(buf, "%u\n", tz->tzp->sustainable_power);
+ else
+ return -EIO;
+}
+
+static ssize_t
+sustainable_power_store(struct device *dev, struct device_attribute *devattr,
+ const char *buf, size_t count)
+{
+ struct thermal_zone_device *tz = to_thermal_zone(dev);
+ u32 sustainable_power;
+
+ if (!tz->tzp)
+ return -EIO;
+
+ if (kstrtou32(buf, 10, &sustainable_power))
+ return -EINVAL;
+
+ tz->tzp->sustainable_power = sustainable_power;
+
+ return count;
+}
+static DEVICE_ATTR(sustainable_power, S_IWUSR | S_IRUGO, sustainable_power_show,
+ sustainable_power_store);
+
+#define create_s32_tzp_attr(name) \
+ static ssize_t \
+ name##_show(struct device *dev, struct device_attribute *devattr, \
+ char *buf) \
+ { \
+ struct thermal_zone_device *tz = to_thermal_zone(dev); \
+ \
+ if (tz->tzp) \
+ return sprintf(buf, "%u\n", tz->tzp->name); \
+ else \
+ return -EIO; \
+ } \
+ \
+ static ssize_t \
+ name##_store(struct device *dev, struct device_attribute *devattr, \
+ const char *buf, size_t count) \
+ { \
+ struct thermal_zone_device *tz = to_thermal_zone(dev); \
+ s32 value; \
+ \
+ if (!tz->tzp) \
+ return -EIO; \
+ \
+ if (kstrtos32(buf, 10, &value)) \
+ return -EINVAL; \
+ \
+ tz->tzp->name = value; \
+ \
+ return count; \
+ } \
+ static DEVICE_ATTR(name, S_IWUSR | S_IRUGO, name##_show, name##_store)
+
+create_s32_tzp_attr(k_po);
+create_s32_tzp_attr(k_pu);
+create_s32_tzp_attr(k_i);
+create_s32_tzp_attr(k_d);
+create_s32_tzp_attr(integral_cutoff);
+#undef create_s32_tzp_attr
+
+static struct device_attribute *dev_tzp_attrs[] = {
+ &dev_attr_sustainable_power,
+ &dev_attr_k_po,
+ &dev_attr_k_pu,
+ &dev_attr_k_i,
+ &dev_attr_k_d,
+ &dev_attr_integral_cutoff,
+};
+
+static int create_power_allocator_tzp_attrs(struct device *dev)
+{
+ int i;
+
+ for (i = 0; i < ARRAY_SIZE(dev_tzp_attrs); i++) {
+ int ret;
+ struct device_attribute *dev_attr = dev_tzp_attrs[i];
+
+ ret = device_create_file(dev, dev_attr);
+ if (ret)
+ return ret;
+ }
+
+ return 0;
+}
+
+#else /* !CONFIG_THERMAL_GOV_POWER_ALLOCATOR */
+static int create_power_allocator_tzp_attrs(struct device *dev)
+{
+ return 0;
+}
+#endif
+
/**
* power_actor_get_max_power() - get the maximum power that a cdev can consume
* @cdev: pointer to &thermal_cooling_device
@@ -1712,6 +1817,11 @@ struct thermal_zone_device *thermal_zone_device_register(const char *type,
if (result)
goto unregister;

+ /* Add power_allocator specific thermal zone params */
+ result = create_power_allocator_tzp_attrs(&tz->device);
+ if (result)
+ goto unregister;
+
/* Update 'this' zone's governor information */
mutex_lock(&thermal_governor_lock);

--
1.9.1