From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932736AbcEXM5t (ORCPT ); Tue, 24 May 2016 08:57:49 -0400 Received: from foss.arm.com ([217.140.101.70]:57293 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751820AbcEXM5s (ORCPT ); Tue, 24 May 2016 08:57:48 -0400 Date: Tue, 24 May 2016 13:57:42 +0100 From: Javi Merino To: Caesar Wang Cc: edubezval@gmail.com, Heiko Stuebner , dianders@chromium.org, briannorris@google.com, smbarber@google.com, linux-rockchip@lists.infradead.org, cf@rock-chips.com, huangtao@rock-chips.com, dmitry.torokhov@gmail.com, Sascha Hauer , Zhang Rui , linux-pm@vger.kernel.org, Jonathan Corbet , Laxman Dewangan , Durgadoss R , Leo Yan , Ni Wade , Andy Champ , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2 1/5] thermal: Add support for hardware-tracked trip points Message-ID: <20160524125741.GA8979@e104805> References: <1462268013-14992-1-git-send-email-wxt@rock-chips.com> <1462268013-14992-2-git-send-email-wxt@rock-chips.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <1462268013-14992-2-git-send-email-wxt@rock-chips.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, May 03, 2016 at 05:33:29PM +0800, Caesar Wang wrote: > From: Sascha Hauer > > This adds support for hardware-tracked trip points to the device tree > thermal sensor framework. > > The framework supports an arbitrary number of trip points. Whenever > the current temperature is updated, the trip points immediately > below and above the current temperature are found. A .set_trips > callback is then called with the temperatures. If there is no trip > point above or below the current temperature, the passed trip > temperature will be -INT_MAX or INT_MAX respectively. In this callback, > the driver should program the hardware such that it is notified > when either of these trip points are triggered. When a trip point > is triggered, the driver should call `thermal_zone_device_update' > for the respective thermal zone. This will cause the trip points > to be updated again. > > If .set_trips is not implemented, the framework behaves as before. > > This patch is based on an earlier version from Mikko Perttunen > > > Signed-off-by: Sascha Hauer > Signed-off-by: Caesar Wang > Cc: Zhang Rui > Cc: Eduardo Valentin > Cc: linux-pm@vger.kernel.org > > --- > > Changes in v2: > - update the sysfs-api.txt for set_trips > > Documentation/thermal/sysfs-api.txt | 7 +++++ > drivers/thermal/thermal_core.c | 52 +++++++++++++++++++++++++++++++++++++ > include/linux/thermal.h | 3 +++ > 3 files changed, 62 insertions(+) > > diff --git a/Documentation/thermal/sysfs-api.txt b/Documentation/thermal/sysfs-api.txt > index efc3f3d..75d8838 100644 > --- a/Documentation/thermal/sysfs-api.txt > +++ b/Documentation/thermal/sysfs-api.txt > @@ -49,6 +49,9 @@ temperature) and throttle appropriate devices. > .bind: bind the thermal zone device with a thermal cooling device. > .unbind: unbind the thermal zone device with a thermal cooling device. > .get_temp: get the current temperature of the thermal zone. > + .set_trips: set the trip points window. Whenever the current temperature > + is updated, the trip points immediately below and above the > + current temperature are found. > .get_mode: get the current mode (enabled/disabled) of the thermal zone. > - "enabled" means the kernel thermal management is enabled. > - "disabled" will prevent kernel thermal driver action upon trip points > @@ -95,6 +98,10 @@ temperature) and throttle appropriate devices. > get_temp: a pointer to a function that reads the > sensor temperature. This is mandatory > callback provided by sensor driver. > + set_trips: a pointer to a function that sets a > + temperature window. When this window is > + left the driver must inform the thermal > + core via thermal_zone_device_update. > get_trend: a pointer to a function that reads the > sensor temperature trend. > set_emul_temp: a pointer to a function that sets > diff --git a/drivers/thermal/thermal_core.c b/drivers/thermal/thermal_core.c > index 5133cd1..e5bfbd3 100644 > --- a/drivers/thermal/thermal_core.c > +++ b/drivers/thermal/thermal_core.c > @@ -520,6 +520,51 @@ exit: > } > EXPORT_SYMBOL_GPL(thermal_zone_get_temp); > > +static void thermal_zone_set_trips(struct thermal_zone_device *tz) > +{ > + int low = -INT_MAX; > + int high = INT_MAX; > + int trip_temp, hysteresis; > + int temp = tz->temperature; > + int i, ret; > + > + if (!tz->ops->set_trips) > + return; > + > + for (i = 0; i < tz->trips; i++) { > + int trip_low; > + > + tz->ops->get_trip_temp(tz, i, &trip_temp); > + tz->ops->get_trip_hyst(tz, i, &hysteresis); > + > + trip_low = trip_temp - hysteresis; > + > + if (trip_low < temp && trip_low > low) > + low = trip_low; > + > + if (trip_temp > temp && trip_temp < high) > + high = trip_temp; > + } > + > + /* No need to change trip points */ > + if (tz->prev_low_trip == low && tz->prev_high_trip == high) > + return; > + > + tz->prev_low_trip = low; > + tz->prev_high_trip = high; > + > + dev_dbg(&tz->device, "new temperature boundaries: %d < x < %d\n", > + low, high); > + > + /* > + * Set a temperature window. When this window is left the driver > + * must inform the thermal core via thermal_zone_device_update. > + */ > + ret = tz->ops->set_trips(tz, low, high); > + if (ret) > + dev_err(&tz->device, "Failed to set trips: %d\n", ret); This function can be called at the same time from multiple places so it should be reentrant. I think you should call mutex_lock(tz->lock) before "if (tz->prev_low_trip == low && ..." and unlock it here. > +} > + > static void update_temperature(struct thermal_zone_device *tz) > { > int temp, ret; > @@ -569,6 +614,8 @@ void thermal_zone_device_update(struct thermal_zone_device *tz) > > update_temperature(tz); > > + thermal_zone_set_trips(tz); > + > for (count = 0; count < tz->trips; count++) > handle_thermal_trip(tz, count); > } > @@ -754,6 +801,9 @@ trip_point_hyst_store(struct device *dev, struct device_attribute *attr, > */ > ret = tz->ops->set_trip_hyst(tz, trip, temperature); > > + if (!ret) > + thermal_zone_set_trips(tz); > + You should add a similar call to thermal_zone_set_trips() in trip_point_temp_store() > return ret ? ret : count; > } > > @@ -1843,6 +1893,8 @@ struct thermal_zone_device *thermal_zone_device_register(const char *type, > tz->trips = trips; > tz->passive_delay = passive_delay; > tz->polling_delay = polling_delay; > + tz->prev_low_trip = INT_MAX; > + tz->prev_high_trip = -INT_MAX; > /* A new thermal zone needs to be updated anyway. */ > atomic_set(&tz->need_update, 1); > > diff --git a/include/linux/thermal.h b/include/linux/thermal.h > index e45abe7..e258359 100644 > --- a/include/linux/thermal.h > +++ b/include/linux/thermal.h > @@ -98,6 +98,7 @@ struct thermal_zone_device_ops { > int (*unbind) (struct thermal_zone_device *, > struct thermal_cooling_device *); > int (*get_temp) (struct thermal_zone_device *, int *); > + int (*set_trips) (struct thermal_zone_device *, int, int); > int (*get_mode) (struct thermal_zone_device *, > enum thermal_device_mode *); > int (*set_mode) (struct thermal_zone_device *, > @@ -199,6 +200,8 @@ struct thermal_zone_device { > int last_temperature; > int emul_temperature; > int passive; > + int prev_low_trip; > + int prev_high_trip; Please document these fields in the kerneldoc comment before struct thermal_zone_device. > unsigned int forced_passive; > atomic_t need_update; > struct thermal_zone_device_ops *ops; Cheers, Javi