[PATCH] thermal: document struct thermal_zone_device and thermal_governor

Javi Merino
2014-06-02T17:26:33Z

Document struct thermal_zone_device and struct thermal_governor fields
and their use by the thermal framework code.

Cc: Zhang Rui <rui.zhang@intel.com>
Cc: Eduardo Valentin <edubezval@gmail.com>
Signed-off-by: Javi Merino <javi.merino@arm.com>

---

Hi linux-pm,

I have some patches that add new fields to these structures but I
don't have a good place to describe those fields as these structs are
mostly undocumented so I thought I'd document them.

Changes since v1:
* Clarified that some parameters are currently only used by the
step-wise governor.
* Clarified that forced_passive operates on ACPI processor cooling
devices.

include/linux/thermal.h | 45 +++++++++++++++++++++++++++++++++++++++++++--
1 file changed, 43 insertions(+), 2 deletions(-)

diff --git a/include/linux/thermal.h b/include/linux/thermal.h
index f7e11c7ea7d9..6fca46c82c4d 100644
--- a/include/linux/thermal.h
+++ b/include/linux/thermal.h
@@ -158,6 +158,41 @@ struct thermal_attr {
char name[THERMAL_NAME_LENGTH];
};

+/**
+ * struct thermal_zone_device - structure for a thermal zone
+ * @id: unique id number for each thermal zone
+ * @type: the thermal zone device type
+ * @device: struct device for this thermal zone
+ * @trip_temp_attrs: attributes for trip points for sysfs: trip temperature
+ * @trip_type_attrs: attributes for trip points for sysfs: trip type
+ * @trip_hyst_attrs: attributes for trip points for sysfs: trip hysteresis
+ * @devdata: private pointer for device private data
+ * @trips: number of trip points the thermal zone supports
+ * @passive_delay: number of milliseconds to wait between polls when
+ * performing passive cooling. Currenty only used by the
+ * step-wise governor
+ * @polling_delay: number of milliseconds to wait between polls when
+ * checking whether trip points have been crossed (0 for
+ * interrupt driven systems)
+ * @temperature: current temperature. This is only for core code,
+ * drivers should use thermal_zone_get_temp() to get the
+ * current temperature
+ * @last_temperature: previous temperature read
+ * @emul_temperature: emulated temperature when using CONFIG_THERMAL_EMULATION
+ * @passive: 1 if you've crossed a passive trip point, 0 otherwise.
+ * Currenty only used by the step-wise governor.
+ * @forced_passive: If > 0, temperature at which to switch on all ACPI
+ * processor cooling devices. Currently only used by the
+ * step-wise governor.
+ * @ops: operations this thermal_zone_device supports
+ * @tzp: thermal zone parameters
+ * @governor: pointer to the governor for this thermal zone
+ * @thermal_instances: list of struct thermal_instance of this thermal zone
+ * @idr: struct idr to generate unique id for this zone's cooling devices
+ * @lock: lock to protect thermal_instances list
+ * @node: node in thermal_tz_list (in thermal_core.c)
+ * @poll_queue: delayed work for polling
+ */
struct thermal_zone_device {
int id;
char type[THERMAL_NAME_LENGTH];
@@ -179,12 +214,18 @@ struct thermal_zone_device {
struct thermal_governor *governor;
struct list_head thermal_instances;
struct idr idr;
- struct mutex lock; /* protect thermal_instances list */
+ struct mutex lock;
struct list_head node;
struct delayed_work poll_queue;
};

-/* Structure that holds thermal governor information */
+/**
+ * struct thermal_governor - structure that holds thermal governor information
+ * @name: name of the governor
+ * @throttle: callback called for every trip point even if temperature is
+ * below the trip point temperature
+ * @governor_list: node in thermal_governor_list (in thermal_core.c)
+ */
struct thermal_governor {
char name[THERMAL_NAME_LENGTH];
int (*throttle)(struct thermal_zone_device *tz, int trip);
--
1.9.1