[v5,3/6] thermal: Added Bang-bang thermal governor

Message ID	1406043436-17068-4-git-send-email-peter@piie.net (mailing list archive)
State	Accepted, archived
Delegated to:	Zhang Rui
Headers	show Return-Path: <linux-pm-owner@kernel.org> From: Peter Feuerer <peter@piie.net> To: LKML <linux-kernel@vger.kernel.org> Cc: Peter Feuerer <peter@piie.net>, Andrew Morton <akpm@linux-foundation.org>, Zhang Rui <rui.zhang@intel.com>, Andreas Mohr <andi@lisas.de>, Borislav Petkov <bp@suse.de>, Javi Merino <javi.merino@arm.com>, linux-pm@vger.kernel.org Subject: [PATCH v5 3/6] thermal: Added Bang-bang thermal governor Date: Tue, 22 Jul 2014 17:37:13 +0200 Message-Id: <1406043436-17068-4-git-send-email-peter@piie.net> In-Reply-To: <1406043436-17068-1-git-send-email-peter@piie.net> References: <1398561815-22033-1-git-send-email-peter@piie.net> <1406043436-17068-1-git-send-email-peter@piie.net> Sender: linux-pm-owner@vger.kernel.org Precedence: bulk

diff --git a/drivers/thermal/Kconfig b/drivers/thermal/Kconfig index f9a1386..fa14d56 100644 --- a/drivers/thermal/Kconfig +++ b/drivers/thermal/Kconfig @@ -84,6 +84,16 @@ config THERMAL_GOV_STEP_WISE Enable this to manage platform thermals using a simple linear governor. +config THERMAL_GOV_BANG_BANG + bool "Bang Bang thermal governor" + default n + help + Enable this to manage platform thermals using bang bang governor. + + Say 'Y' here if you want to use two point temperature regulation + used for fans without throttling. Some fan drivers depend on this + governor to be enabled (e.g. acerhdf). + config THERMAL_GOV_USER_SPACE bool "User_space thermal governor" help diff --git a/drivers/thermal/Makefile b/drivers/thermal/Makefile index de0636a..a675980 100644 --- a/drivers/thermal/Makefile +++ b/drivers/thermal/Makefile @@ -11,6 +11,7 @@ thermal_sys-$(CONFIG_THERMAL_OF) += of-thermal.o # governors thermal_sys-$(CONFIG_THERMAL_GOV_FAIR_SHARE) += fair_share.o +thermal_sys-$(CONFIG_THERMAL_GOV_BANG_BANG) += gov_bang_bang.o thermal_sys-$(CONFIG_THERMAL_GOV_STEP_WISE) += step_wise.o thermal_sys-$(CONFIG_THERMAL_GOV_USER_SPACE) += user_space.o diff --git a/drivers/thermal/gov_bang_bang.c b/drivers/thermal/gov_bang_bang.c new file mode 100644 index 0000000..c5dd76b --- /dev/null +++ b/drivers/thermal/gov_bang_bang.c @@ -0,0 +1,131 @@ +/* + * gov_bang_bang.c - A simple thermal throttling governor using hysteresis + * + * Copyright (C) 2014 Peter Feuerer <peter@piie.net> + * + * Based on step_wise.c with following Copyrights: + * Copyright (C) 2012 Intel Corp + * Copyright (C) 2012 Durgadoss R <durgadoss.r@intel.com> + * + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation, version 2. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See + * the GNU General Public License for more details. + * + */ + +#include <linux/thermal.h> + +#include "thermal_core.h" + +static void thermal_zone_trip_update(struct thermal_zone_device *tz, int trip) +{ + long trip_temp; + unsigned long trip_hyst; + struct thermal_instance *instance; + + tz->ops->get_trip_temp(tz, trip, &trip_temp); + tz->ops->get_trip_hyst(tz, trip, &trip_hyst); + + dev_dbg(&tz->device, "Trip%d[temp=%ld]:temp=%d:hyst=%ld\n", + trip, trip_temp, tz->temperature, + trip_hyst); + + mutex_lock(&tz->lock); + + list_for_each_entry(instance, &tz->thermal_instances, tz_node) { + if (instance->trip != trip) + continue; + + /* in case fan is in initial state, switch the fan off */ + if (instance->target == THERMAL_NO_TARGET) + instance->target = 0; + + /* in case fan is neither on nor off set the fan to active */ + if (instance->target != 0 && instance->target != 1) { + pr_warn("Thermal instance %s controlled by bang-bang has unexpected state: %ld\n", + instance->name, instance->target); + instance->target = 1; + } + + /* + * enable fan when temperature exceeds trip_temp and disable + * the fan in case it falls below trip_temp minus hysteresis + */ + if (instance->target == 0 && tz->temperature >= trip_temp) + instance->target = 1; + else if (instance->target == 1 && + tz->temperature < trip_temp - trip_hyst) + instance->target = 0; + + dev_dbg(&instance->cdev->device, "target=%d\n", + (int)instance->target); + + instance->cdev->updated = false; /* cdev needs update */ + } + + mutex_unlock(&tz->lock); +} + +/** + * bang_bang_control - controls devices associated with the given zone + * @tz - thermal_zone_device + * @trip - the trip point + * + * Regulation Logic: a two point regulation, deliver cooling state depending + * on the previous state shown in this diagram: + * + * Fan: OFF ON + * + * | + * | + * trip_temp: +---->+ + * | | ^ + * | | | + * | | Temperature + * (trip_temp - hyst): +<----+ + * | + * | + * | + * + * * If the fan is not running and temperature exceeds trip_temp, the fan + * gets turned on. + * * In case the fan is running, temperature must fall below + * (trip_temp - hyst) so that the fan gets turned off again. + * + */ +static int bang_bang_control(struct thermal_zone_device *tz, int trip) +{ + struct thermal_instance *instance; + + thermal_zone_trip_update(tz, trip); + + mutex_lock(&tz->lock); + + list_for_each_entry(instance, &tz->thermal_instances, tz_node) + thermal_cdev_update(instance->cdev); + + mutex_unlock(&tz->lock); + + return 0; +} + +static struct thermal_governor thermal_gov_bang_bang = { + .name = "bang_bang", + .throttle = bang_bang_control, +}; + +int thermal_gov_bang_bang_register(void) +{ + return thermal_register_governor(&thermal_gov_bang_bang); +} + +void thermal_gov_bang_bang_unregister(void) +{ + thermal_unregister_governor(&thermal_gov_bang_bang); +} diff --git a/drivers/thermal/thermal_core.c b/drivers/thermal/thermal_core.c index 71b0ec0..4c2726b 100644 --- a/drivers/thermal/thermal_core.c +++ b/drivers/thermal/thermal_core.c @@ -1790,6 +1790,10 @@ static int __init thermal_register_governors(void) if (result) return result; + result = thermal_gov_bang_bang_register(); + if (result) + return result; + return thermal_gov_user_space_register(); } @@ -1797,6 +1801,7 @@ static void thermal_unregister_governors(void) { thermal_gov_step_wise_unregister(); thermal_gov_fair_share_unregister(); + thermal_gov_bang_bang_unregister(); thermal_gov_user_space_unregister(); } diff --git a/drivers/thermal/thermal_core.h b/drivers/thermal/thermal_core.h index 3db339f..d15d243 100644 --- a/drivers/thermal/thermal_core.h +++ b/drivers/thermal/thermal_core.h @@ -69,6 +69,14 @@ static inline int thermal_gov_fair_share_register(void) { return 0; } static inline void thermal_gov_fair_share_unregister(void) {} #endif /* CONFIG_THERMAL_GOV_FAIR_SHARE */ +#ifdef CONFIG_THERMAL_GOV_BANG_BANG +int thermal_gov_bang_bang_register(void); +void thermal_gov_bang_bang_unregister(void); +#else +static inline int thermal_gov_bang_bang_register(void) { return 0; } +static inline void thermal_gov_bang_bang_unregister(void) {} +#endif /* CONFIG_THERMAL_GOV_BANG_BANG */ + #ifdef CONFIG_THERMAL_GOV_USER_SPACE int thermal_gov_user_space_register(void); void thermal_gov_user_space_unregister(void);

[v5,3/6] thermal: Added Bang-bang thermal governor

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