On Thursday, July 19, 2012, R, Durgadoss wrote:
> Hi Rui,
>
> > -----Original Message-----
> > From: Zhang, Rui
> > Sent: Thursday, July 19, 2012 12:01 PM
> > To: linux-acpi@xxxxxxxxxxxxxxx; linux-pm@xxxxxxxxxxxxxxx
> > Cc: Rafael J. Wysocki; Matthew Garrett; Len Brown; R, Durgadoss; Eduardo
> > Valentin; Amit Kachhap; Wei Ni; Zhang, Rui
> > Subject: [PATCH 02/16] Thermal: Add Hysteresis attributes
> >
> > From: Durgadoss R <dugardoss.r@xxxxxxxxx>
> >
> > The Linux Thermal Framework does not support hysteresis
> > attributes. Most thermal sensors, today, have a
> > hysteresis value associated with trip points.
> >
> > This patch adds hysteresis attributes on a per-trip-point
> > basis, to the Thermal Framework. These attributes are
> > optionally writable.
> >
> > Signed-off-by: Durgadoss R <durgadoss.r@xxxxxxxxx>
> > Signed-off-by: Zhang Rui <rui.zhang@xxxxxxxxx>
> > ---
> > Documentation/thermal/sysfs-api.txt | 6 +++
> > drivers/thermal/thermal_sys.c | 89
> > ++++++++++++++++++++++++++++++++---
> > include/linux/thermal.h | 5 ++
> > 3 files changed, 94 insertions(+), 6 deletions(-)
> >
> > diff --git a/Documentation/thermal/sysfs-api.txt
> > b/Documentation/thermal/sysfs-api.txt
> > index 0c7c423..3c8c2f8 100644
> > --- a/Documentation/thermal/sysfs-api.txt
> > +++ b/Documentation/thermal/sysfs-api.txt
> > @@ -121,6 +121,7 @@ if hwmon is compiled in or built as a module.
> > |---mode: Working mode of the thermal zone
> > |---trip_point_[0-*]_temp: Trip point temperature
> > |---trip_point_[0-*]_type: Trip point type
> > + |---trip_point_[0-*]_hyst: Hysteresis value for this trip point
> >
> > Thermal cooling device sys I/F, created once it's registered:
> > /sys/class/thermal/cooling_device[0-*]:
> > @@ -190,6 +191,11 @@ trip_point_[0-*]_type
> > thermal zone.
> > RO, Optional
> >
> [cut.]
>
> > + /* create Optional trip hyst attribute */
> > + if (!tz->ops->get_trip_hyst)
> > + continue;
> > + snprintf(tz->trip_hyst_attrs[indx].name,
> > THERMAL_NAME_LENGTH,
> > + "trip_point_%d_hyst", indx);
> > +
> > + sysfs_attr_init(&tz->trip_hyst_attrs[indx].attr.attr);
> > + tz->trip_hyst_attrs[indx].attr.attr.name =
> > + tz->trip_hyst_attrs[indx].name;
> > + tz->trip_hyst_attrs[indx].attr.attr.mode = S_IRUGO;
> > + tz->trip_hyst_attrs[indx].attr.show = trip_point_hyst_show;
> > + if (tz->ops->set_trip_hyst) {
> > + tz->trip_hyst_attrs[indx].attr.attr.mode |= S_IWUSR;
> > + tz->trip_hyst_attrs[indx].attr.store =
> > + trip_point_hyst_store;
> > + }
> > +
> > + device_create_file(&tz->device,
> > + &tz->trip_hyst_attrs[indx].attr);
> > }
> > return 0;
> > }
> > @@ -1151,9 +1225,13 @@ static void remove_trip_attrs(struct
> > thermal_zone_device *tz)
> > &tz->trip_type_attrs[indx].attr);
> > device_remove_file(&tz->device,
> > &tz->trip_temp_attrs[indx].attr);
> > + if (tz->ops->get_trip_hyst)
> > + device_remove_file(&tz->device,
> > + &tz->trip_hyst_attrs[indx].attr);
> > }
> > kfree(tz->trip_type_attrs);
> > kfree(tz->trip_temp_attrs);
>
> I believe we should have a check here for 'if (tz->ops->get_trip_hyst)' and then
> only free this, if required.
>
> > + kfree(tz->trip_hyst_attrs);
> > }
No, we don't have to, kfree() checks for NULL pointers.
Thanks,
Rafael
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