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Subject: Re: [PATCH 0/3] Platform/RasberryPi: Thermal zone
To: Jeremy Linton <jeremy.linton@arm.com>, devel@edk2.groups.io
Cc: Leif Lindholm <leif@nuviainc.com>, Pete Batard <pete@akeo.ie>,
 Andrei Warkentin <awarkentin@vmware.com>,
 Samer El-Haj-Mahmoud <Samer.El-Haj-Mahmoud@arm.com>
References: <20200813230056.40526-1-jeremy.linton@arm.com>
From: "Ard Biesheuvel" <ard.biesheuvel@arm.com>
Message-ID: <7dcba3be-778e-b3d5-20f5-ae0b205dd826@arm.com>
Date: Mon, 17 Aug 2020 16:31:27 +0200
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On 8/14/20 1:00 AM, Jeremy Linton wrote:
> This set creates a basic thermal zone, which reads the
> SOC temp via a direct register read in AML. It also
> adds an active cooling policy using a GPIO pin for fan
> control that can optionally be enabled/disabled by the
> user from the BDS.
> 
> With the fan enabled it should be possible to see the
> soc temp like:
> 
> # sensors
> acpitz-acpi-0
> Adapter: ACPI interface
> temp1:        +57.6C  (crit = +90.0C)
> 
> and the fan state may be read/cycled with:
> 
> /sys/bus/acpi/devices/PNP0C06:00/PNP0C0B:00/physical_node/thermal_cooling/cur_state
> 
> Cc: Leif Lindholm <leif@nuviainc.com>
> Cc: Pete Batard <pete@akeo.ie>
> Cc: Andrei Warkentin <awarkentin@vmware.com>
> Cc: Ard Biesheuvel <ard.biesheuvel@arm.com>
> Cc: Samer El-Haj-Mahmoud <Samer.El-Haj-Mahmoud@arm.com>
> 
> Jeremy Linton (3):
>    Platform/RaspberryPi4: Add a basic thermal zone
>    Platform/RaspberryPi4: Create ACPI fan object
>    Platform/RaspberryPi: Add entry for user fan control
> 

I like this code a lot. It is very helpful to have working sample AML 
code that implements a thermal zone. Could you elaborate on the 
additional components that are needed for this? Is this a standard cape 
(or whatever rpi calls it)? I assume the fan just switches between 0 and 
max rpm depending on the actual temp wrt the trip point?



>   Platform/RaspberryPi/AcpiTables/Dsdt.asl           | 31 ++++++++
>   Platform/RaspberryPi/Drivers/ConfigDxe/ConfigDxe.c | 55 ++++++++++++++
>   .../RaspberryPi/Drivers/ConfigDxe/ConfigDxe.inf    |  3 +
>   .../RaspberryPi/Drivers/ConfigDxe/ConfigDxeHii.uni |  5 ++
>   .../RaspberryPi/Drivers/ConfigDxe/ConfigDxeHii.vfr | 17 +++++
>   .../RaspberryPi/Drivers/ConfigDxe/SsdtThermal.asl  | 83 ++++++++++++++++++++++
>   Platform/RaspberryPi/Include/ConfigVars.h          |  4 ++
>   Platform/RaspberryPi/RPi3/RPi3.dsc                 |  5 ++
>   Platform/RaspberryPi/RPi4/RPi4.dsc                 |  8 +++
>   Platform/RaspberryPi/RaspberryPi.dec               |  1 +
>   .../Bcm27xx/Include/IndustryStandard/Bcm2711.h     |  2 +
>   11 files changed, 214 insertions(+)
>   create mode 100644 Platform/RaspberryPi/Drivers/ConfigDxe/SsdtThermal.asl
>