On 5/29/14, Javi Merino [off-list ref] wrote:

Hi Amit,

On Thu, May 29, 2014 at 09:15:31AM +0100, Amit Daniel Kachhap wrote:

quoted

This patch adds notification infrastructure for any requests related to
cooling
states. The notifier structure passed is of both Get/Set type. So the
receiver
of these can sense the new/cur/max cooling state as decided by thermal
governor.
In addition to that it can also override the cooling state and may do
something
interesting after receiving these CPU cooling events such as masking some
states, enabling some extra conditional states or perform any extra
operation
for aggressive thermal cooling.
The notfications events can be of type,

1. COOLING_SET_STATE_PRE
2. COOLING_SET_STATE_POST
3. COOLING_GET_CUR_STATE
4. COOLING_GET_MAX_STATE

Signed-off-by: Amit Daniel Kachhap <redacted>
---
 Documentation/thermal/sysfs-api.txt |   21 +++++++++++
 drivers/thermal/thermal_core.c      |   69
++++++++++++++++++++++++++++++++++-
 include/linux/thermal.h             |   21 +++++++++++
 3 files changed, 109 insertions(+), 2 deletions(-)

diff --git a/Documentation/thermal/sysfs-api.txt

b/Documentation/thermal/sysfs-api.txt
index 87519cb..5f45e03 100644

--- a/Documentation/thermal/sysfs-api.txt
+++ b/Documentation/thermal/sysfs-api.txt

@@ -92,6 +92,27 @@ temperature) and throttle appropriate devices.
     It deletes the corresponding entry form /sys/class/thermal folder

and
     unbind itself from all the thermal zone devices using it.

+1.2.3 int thermal_cooling_register_notifier(struct notifier_block *nb)
+
+    This interface function registers the client notifier handler. The
notifier
+    handler can use this to monitor or update any cooling state
requests.
+    nb: notifier structure containing client notifier handler.
+
+1.2.4 int thermal_cooling_unregister_notifier(struct notifier_block *nb)
+
+    This interface function unregisters the client notifier handler.
+    nb: notifier structure containing client notifier handler.
+
+1.2.5 int thermal_cooling_notify_states(struct thermal_cooling_status
*request,enum cooling_state_ops op)
+
+    This interface function invokes the earlier registered cooling states
handler.
+    request: holds the relevant cooling state value.
+	.cur_state: current cooling state.
+	.new_state: new cooling state to be set.
+	.max_state: max cooling state.
+	.devdata: driver private data pointer.
+    op: describes various operation supported.
+
 1.3 interface for binding a thermal zone device with a thermal cooling
device
 1.3.1 int thermal_zone_bind_cooling_device(struct thermal_zone_device
*tz,
 	int trip, struct thermal_cooling_device *cdev,

diff --git a/drivers/thermal/thermal_core.c

b/drivers/thermal/thermal_core.c
index 71b0ec0..1a60f83 100644

--- a/drivers/thermal/thermal_core.c
+++ b/drivers/thermal/thermal_core.c

@@ -52,6 +52,8 @@ static DEFINE_MUTEX(thermal_idr_lock);
 static LIST_HEAD(thermal_tz_list);
 static LIST_HEAD(thermal_cdev_list);
 static LIST_HEAD(thermal_governor_list);
+/* Notfier list to validates/updates the cpufreq cooling states */
+static BLOCKING_NOTIFIER_HEAD(cooling_state_notifier_list);

 static DEFINE_MUTEX(thermal_list_lock);
 static DEFINE_MUTEX(thermal_governor_lock);

@@ -1073,8 +1075,71 @@ static struct class thermal_class = {
 };

 /**
- * __thermal_cooling_device_register() - register a new thermal cooling

device
- * @np:		a pointer to a device tree node.
+ * thermal_cooling_notify_states - Invoke the necessary cooling states
handler.
+ * @request: holds the relevant cooling state value. say if the cooling
state
+ * operation is of type COOLING_GET_MAX_STATE, then request holds
+ * the current max cooling state value.
+ * @op: different operations supported
+ *
+ * This API allows the registered user to recieve the different cooling
+ * notifications like current state, max state and set state.
+ *
+ * Return: 0 (success)
+ */
+int thermal_cooling_notify_states(struct thermal_cooling_status
*request,
+				enum cooling_state_ops op)
+{
+	/* Invoke the notifiers which have registered for this state change */
+	if (op == COOLING_SET_STATE_PRE ||
+		op == COOLING_SET_STATE_POST ||
+		op == COOLING_GET_MAX_STATE ||
+		op == COOLING_GET_CUR_STATE) {
+		blocking_notifier_call_chain(
+			&cooling_state_notifier_list, op, request);
+	}
+	return 0;
+}
+EXPORT_SYMBOL_GPL(thermal_cooling_notify_states);
+
+/**
+ * thermal_cooling_register_notifier - registers a notifier with thermal
cooling.
+ * @nb:	notifier function to register.
+ *
+ * Add a driver to receive all cooling notifications like current state,
+ * max state and set state. The drivers after reading the events can
perform
+ * some mapping like grouping some P states into 1 cooling state.
+ *
+ * Return: 0 (success)
+ */
+int thermal_cooling_register_notifier(struct notifier_block *nb)
+{
+	int ret = 0;
+	ret = blocking_notifier_chain_register(
+				&cooling_state_notifier_list, nb);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(thermal_cooling_register_notifier);
+
+/**
+ * thermal_cooling_unregister_notifier - unregisters a notifier with
thermal
+ * cooling.
+ * @nb:	notifier function to unregister.
+ *
+ * Removes a driver to receive further cooling notifications.
+ *
+ * Return: 0 (success)

Or %-ENOENT if the notifier is not registered.

quoted

+ */
+int thermal_cooling_unregister_notifier(struct notifier_block *nb)
+{
+	int ret = 0;
+	ret = blocking_notifier_chain_unregister(
+				&cooling_state_notifier_list, nb);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(thermal_cooling_unregister_notifier);
+
+/**
+ * thermal_cooling_device_register() - register a new thermal cooling
device

This is wrong, the function below this comment is still
__thermal_cooling_device_register() whose first parameter is np, not
type.

I did not add this. This seems wrong. Will modify this as a fix in the version.

Thanks,
Amit

quoted

  * @type:	the thermal cooling device type.
  * @devdata:	device private data.
  * @ops:		standard thermal cooling devices callbacks.

Cheers,
Javi