Re: [PATCH v1 3/6] thermal: thermal-core: Add notifications support for the cooling states

["Javi Merino" <javi.merino@arm.com>]

On Mon, Jun 02, 2014 at 10:31:19AM +0100, Amit Kachhap wrote:
> On 5/29/14, Javi Merino <javi.merino@arm.com> wrote:
> > Hi Amit,
> >
> > On Thu, May 29, 2014 at 09:15:31AM +0100, Amit Daniel Kachhap wrote:
> >> 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 <amit.daniel@samsung.com>
> >> ---
> >>  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.
> >
> >> + */
> >> +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.

You removed it, probably by mistake.  If you look at the top of this
hunk you will find:

- * __thermal_cooling_device_register() - register a new thermal cooling device
- * @np:		a pointer to a device tree node.

Cheers,
Javi