Re: [linux-pm] [PATCH RESEND] thermal: add generic cpufreq cooling implementation
From: Rafael J. Wysocki
Date: Mon Sep 10 2012 - 16:20:24 EST
On Monday, September 10, 2012, Rafael J. Wysocki wrote:
> On Monday, September 10, 2012, Zhang Rui wrote:
> > Refreshed to remove the notifier mechanism as we do not have a real user of it.
> > if there is no problem, I'll apply the whole patch set to thermal next tree.
> > From: Amit Daniel Kachhap <amit.kachhap@xxxxxxxxxx>
> > Date: Thu, 16 Aug 2012 17:11:40 +0530
> > This patchset introduces a new generic cooling device based on cpufreq
> > that can be used on non-ACPI platforms. As a proof of concept, we have
> > drivers for the following platforms using this mechanism now:
> > * Samsung Exynos (Exynos4 and Exynos5) in the current patchset.
> > * Freescale i.MX (git://git.linaro.org/people/amitdanielk/linux.git imx6q_thermal)
> > There is a small change in cpufreq cooling registration APIs, so a minor
> > change is needed for Freescale platforms.
> > Brief Description:
> > 1) The generic cooling devices code is placed inside driver/thermal/*
> > as placing inside acpi folder will need un-necessary enabling of acpi
> > code. This code is architecture independent.
> > 2) This patchset adds generic cpu cooling low level implementation
> > through frequency clipping. In future, other cpu related cooling
> > devices may be added here. An ACPI version of this already exists
> > (drivers/acpi/processor_thermal.c) .But this will be useful for
> > platforms like ARM using the generic thermal interface along with the
> > generic cpu cooling devices. The cooling device registration API's
> > return cooling device pointers which can be easily binded with the
> > thermal zone trip points. The important APIs exposed are,
> > a) struct thermal_cooling_device *cpufreq_cooling_register(
> > struct cpumask *clip_cpus)
> > b) void cpufreq_cooling_unregister(struct thermal_cooling_device *cdev)
> > 3) Samsung exynos platform thermal implementation is done using the
> > generic cpu cooling APIs and the new trip type. The temperature sensor
> > driver present in the hwmon folder(registered as hwmon driver) is moved
> > to thermal folder and registered as a thermal driver.
> > A simple data/control flow diagrams is shown below,
> > Core Linux thermal <-----> Exynos thermal interface <----- Temperature Sensor
> > | |
> > \|/ |
> > Cpufreq cooling device <---------------
> > TODO:
> > *Will send the DT enablement patches later after the driver is merged.
> > This patch:
> > Add support for generic cpu thermal cooling low level implementations
> > using frequency scaling up/down based on the registration parameters.
> > Different cpu related cooling devices can be registered by the user and
> > the binding of these cooling devices to the corresponding trip points can
> > be easily done as the registration APIs return the cooling device pointer.
> > The user of these APIs are responsible for passing clipping frequency .
> > The drivers can also register to recieve notification about any cooling
> > action called.
> > Cc: Guenter Roeck <guenter.roeck@xxxxxxxxxxxx>
> > Cc: SangWook Ju <sw.ju@xxxxxxxxxxx>
> > Cc: Durgadoss <durgadoss.r@xxxxxxxxx>
> > Cc: Len Brown <lenb@xxxxxxxxxx>
> > Cc: Jean Delvare <khali@xxxxxxxxxxxx>
> > Cc: Kyungmin Park <kmpark@xxxxxxxxxxxxx>
> > Cc: Kukjin Kim <kgene.kim@xxxxxxxxxxx>
> > Signed-off-by: Zhang Rui <rui.zhang@xxxxxxxxx>
> > Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
> > Signed-off-by: Amit Daniel Kachhap <amit.daniel@xxxxxxxxxxx>
> Can you please resend the patch inline (i.e. not as an attachment)?
Sorry, it was inline (obviously). I seem to be too tired.
Please resend it to linux-pm@xxxxxxxxxxxxxxxx The linux-pm list at
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