Copying Narendran. On Mon, May 11, 2015 at 08:04:16PM -0700, Eduardo Valentin wrote: > It is common to have a linear extrapolation from > the current sensor readings and the actual temperature > value. This is specially the case when the sensor > is in use to extrapolate hotspots. > > This patch adds slope and offset constants for > single sensor linear extrapolation equation. Because > the same sensor can be use in different locations, > from board to board, these constants are added > as part of thermal_zone_params. > > The constants are available through sysfs. > > It is up to the device driver to determine > the usage of these values.
> > Signed-off-by: Eduardo Valentin <[email protected]> > --- > Documentation/thermal/sysfs-api.txt | 16 ++++++++++++++++ > drivers/thermal/thermal_core.c | 4 ++++ > include/linux/thermal.h | 11 +++++++++++ > 3 files changed, 31 insertions(+) > > diff --git a/Documentation/thermal/sysfs-api.txt > b/Documentation/thermal/sysfs-api.txt > index 7d44d7f..c1f6864 100644 > --- a/Documentation/thermal/sysfs-api.txt > +++ b/Documentation/thermal/sysfs-api.txt > @@ -190,6 +190,8 @@ Thermal zone device sys I/F, created once it's registered: > |---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 > + |---slope: Slope constant applied as linear > extrapolation > + |---offset: Offset constant applied as linear > extrapolation > > Thermal cooling device sys I/F, created once it's registered: > /sys/class/thermal/cooling_device[0-*]: > @@ -359,6 +361,20 @@ integral_cutoff > Documentation/thermal/power_allocator.txt > RW, Optional > > +slope > + The slope constant used in a linear extrapolation model > + to determine a hotspot temperature based off the sensor's > + raw readings. It is up to the device driver to determine > + the usage of these values. > + RW, Optional > + > +offset > + The offset constant used in a linear extrapolation model > + to determine a hotspot temperature based off the sensor's > + raw readings. It is up to the device driver to determine > + the usage of these values. > + RW, Optional > + > ***************************** > * Cooling device attributes * > ***************************** > diff --git a/drivers/thermal/thermal_core.c b/drivers/thermal/thermal_core.c > index 962de18..04659bf 100644 > --- a/drivers/thermal/thermal_core.c > +++ b/drivers/thermal/thermal_core.c > @@ -944,6 +944,8 @@ create_s32_tzp_attr(k_pu); > create_s32_tzp_attr(k_i); > create_s32_tzp_attr(k_d); > create_s32_tzp_attr(integral_cutoff); > +create_s32_tzp_attr(slope); > +create_s32_tzp_attr(offset); > #undef create_s32_tzp_attr > > static struct device_attribute *dev_tzp_attrs[] = { > @@ -953,6 +955,8 @@ static struct device_attribute *dev_tzp_attrs[] = { > &dev_attr_k_i, > &dev_attr_k_d, > &dev_attr_integral_cutoff, > + &dev_attr_slope, > + &dev_attr_offset, > }; > > static int create_tzp_attrs(struct device *dev) > diff --git a/include/linux/thermal.h b/include/linux/thermal.h > index 6bbe11c..037e9df 100644 > --- a/include/linux/thermal.h > +++ b/include/linux/thermal.h > @@ -302,6 +302,17 @@ struct thermal_zone_params { > > /* threshold below which the error is no longer accumulated */ > s32 integral_cutoff; > + > + /* > + * @slope: slope of a linear temperature adjustment curve. > + * Used by thermal zone drivers. > + */ > + int slope; > + /* > + * @offset: offset of a linear temperature adjustment curve. > + * Used by thermal zone drivers (default 0). > + */ > + int offset; > }; > > struct thermal_genl_event { > -- > 2.3.4 >
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