linux-kernel - Re: [PATCH v3 1/4] platform/x86: (ayn-ec) Add PWM Fan HWMON Interface

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Message-ID: <5531e051-ad62-4cfd-a733-21f04385e1bb@gmx.de>
Date: Mon, 11 Aug 2025 10:38:37 +0200
From: Armin Wolf <W_Armin@....de>
To: Derek John Clark <derekjohn.clark@...il.com>
Cc: Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>,
 Hans de Goede <hansg@...nel.org>, Jean Delvare <jdelvare@...e.com>,
 Guenter Roeck <linux@...ck-us.net>, Alok Tiwari <alok.a.tiwari@...cle.com>,
 David Box <david.e.box@...ux.intel.com>,
 platform-driver-x86@...r.kernel.org, linux-kernel@...r.kernel.org,
 linux-hwmon@...r.kernel.org, linux-doc@...r.kernel.org
Subject: Re: [PATCH v3 1/4] platform/x86: (ayn-ec) Add PWM Fan HWMON Interface

Am 11.08.25 um 00:27 schrieb Derek John Clark:

> On Mon, Jul 28, 2025 at 9:10 PM Armin Wolf <W_Armin@....de> wrote:
>> Am 29.07.25 um 04:58 schrieb Derek John Clark:
>>
>>> On Sat, Jul 26, 2025 at 4:32 PM Armin Wolf <W_Armin@....de> wrote:
>>>> Am 26.07.25 um 22:40 schrieb Derek J. Clark:
>>>>
>>>>> Adds platform driver for AYN Loki and Tectoy Zeenix lines of handheld
>>>>> devices. This patch implements a hwmon interface for EC provided manual
>>>>> PWM fan control and user defined fan curves. A global ACPI lock is used
>>>>> when reading or writing from the EC.
>>>>>
>>>>> There are 4 fan modes implemented in this patch. Modes 0-3 act in
>>>>> accordance with the standard hwmon logic where 0 is 100% fan speed, 1 is
>>>>> manual control, and 2 is automatic control. As the EC only provides 3
>>>>> modes by default, mode 0 is implemented by setting the device to manual
>>>>> and then setting fan speed to 100% directly. In mode 1 the PWM duty cycle
>>>>> is set in sysfs with values [0-255], which are then scaled to the EC max
>>>>> of 128. Mode 4 is an automatic mode where the fan curve is user defined.
>>>>> There are 5 total set points and each set point takes a temperature in
>>>>> Celsius [0-100] and a PWM duty cycle [0-255]. When the CPU temperature
>>>>> reaches a given set point, the corresponding duty cycle is automatically
>>>>> set by the EC.
>>>>>
>>>>> Signed-off-by: Derek J. Clark <derekjohn.clark@...il.com>
>>>>>
>>>>> space
>>>> Interesting, do you have access to such a device? If yes then i would be very interested
>>>> in looking at the ACPI tables shipped with said device.
>>> Hi Armin,
>>>
>>> I have a Loki Max, and know someone with a Loki Zero. Do you want
>>> plain text acpidump or a decoded DSDT.dat attached?
>> I would prefer the plain text acpidump, as the SSDT tables often contain important data.
>>
> Attached is the plain text acpidump, sorry for the delay. I'll also
> note that Ayn provided me with documentation of the EC commands for
> this driver.
>
> Cheers,
> - Derek

Nice :)

I also noticed that the ACPI code itself uses EC register 0xB0 to control the battery thermal limit. This would
conflict with your usage of register 0xB0 as the RED RGB value. Does the documentation mention this register?

Thanks,
Armin Wolf