Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965238AbbDOSHJ (ORCPT ); Wed, 15 Apr 2015 14:07:09 -0400 Received: from mail-pd0-f174.google.com ([209.85.192.174]:36463 "EHLO mail-pd0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932980AbbDOSG5 (ORCPT ); Wed, 15 Apr 2015 14:06:57 -0400 Date: Wed, 15 Apr 2015 11:06:48 -0700 From: Brian Norris To: Sascha Hauer Cc: linux-pm@vger.kernel.org, Zhang Rui , Eduardo Valentin , linux-kernel@vger.kernel.org, Stephen Warren , Mikko Perttunen , kernel@pengutronix.de, linux-mediatek@lists.infradead.org, linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH 12/13] thermal: Add support for hardware-tracked trip points Message-ID: <20150415180648.GS32500@ld-irv-0074> References: <1427385240-6086-1-git-send-email-s.hauer@pengutronix.de> <1427385240-6086-13-git-send-email-s.hauer@pengutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1427385240-6086-13-git-send-email-s.hauer@pengutronix.de> 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 Content-Length: 4819 Lines: 134 Hi Sascha, On Thu, Mar 26, 2015 at 04:53:59PM +0100, Sascha Hauer wrote: > 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 ULONG_MAX or 0 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 > --- > drivers/thermal/thermal_core.c | 41 +++++++++++++++++++++++++++++++++++++++++ > include/linux/thermal.h | 3 +++ > 2 files changed, 44 insertions(+) > > diff --git a/drivers/thermal/thermal_core.c b/drivers/thermal/thermal_core.c > index dcdf45e..7138f8f 100644 > --- a/drivers/thermal/thermal_core.c > +++ b/drivers/thermal/thermal_core.c > @@ -434,6 +434,45 @@ int thermal_zone_get_temp(struct thermal_zone_device *tz, unsigned long *temp) > } > EXPORT_SYMBOL_GPL(thermal_zone_get_temp); > > +static void thermal_zone_set_trips(struct thermal_zone_device *tz) > +{ > + unsigned long low = 0; > + unsigned long high = ULONG_MAX; > + unsigned long trip_temp, hysteresis; > + unsigned long temp = tz->temperature; > + int i; > + > + if (!tz->ops->set_trips) > + return; > + > + /* No need to change trip points */ > + if (temp > tz->prev_low_trip && temp < tz->prev_high_trip) > + return; I see that you don't actually initialize prev_{low,high}_trip during device initialization, so they both start out as zero. I suppose that works here, mostly by coincidence, because it means we'll still always recalculate trip points the first time, but might it make sense to explicitly initialize them to: low = ULONG_MAX high = 0 at init time? (Or, if these change to integer: INT_MAX and -INT_MAX?) Thanks, Brian > + > + for (i = 0; i < tz->trips; i++) { > + unsigned long 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; > + } > + > + tz->prev_low_trip = low; > + tz->prev_high_trip = high; > + > + dev_dbg(&tz->device, "new temperature boundaries: %lu < x < %lu\n", > + low, high); > + > + tz->ops->set_trips(tz, low, high); > +} > + > void thermal_zone_device_update(struct thermal_zone_device *tz) > { > int count; > @@ -460,6 +499,8 @@ void thermal_zone_device_update(struct thermal_zone_device *tz) > dev_dbg(&tz->device, "last_temperature=%lu, current_temperature=%lu\n", > tz->last_temperature, tz->temperature); > > + thermal_zone_set_trips(tz); > + > for (count = 0; count < tz->trips; count++) > handle_thermal_trip(tz, count); > } > diff --git a/include/linux/thermal.h b/include/linux/thermal.h > index ac2897c..b870702 100644 > --- a/include/linux/thermal.h > +++ b/include/linux/thermal.h > @@ -87,6 +87,7 @@ struct thermal_zone_device_ops { > int (*unbind) (struct thermal_zone_device *, > struct thermal_cooling_device *); > int (*get_temp) (struct thermal_zone_device *, unsigned long *); > + int (*set_trips) (struct thermal_zone_device *, unsigned long, unsigned long); > int (*get_mode) (struct thermal_zone_device *, > enum thermal_device_mode *); > int (*set_mode) (struct thermal_zone_device *, > @@ -183,6 +184,8 @@ struct thermal_zone_device { > unsigned long temperature; > unsigned long last_temperature; > unsigned long emul_temperature; > + unsigned long prev_low_trip; > + unsigned long prev_high_trip; > int passive; > unsigned int forced_passive; > const struct thermal_zone_device_ops *ops; > -- > 2.1.4 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-pm" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/