Cutiepi, serdevs, and right way to handle its power button

Cutiepi, serdevs, and right way to handle its power button

[Pavel Machek]

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Hi!

Cutiepie is a small handheld tablet. It has embedded controller
connected via serial to the main system, handling stuff such as power
button and battery percentage. Currently they are using userland
deamon for communication, but I believe that should eventually go into
kernel.

For debugging, it would be really nice to be able to attach my module
to given serdev. Is such thing possible? I see "[PATCH v2 00/19]
Dynamically load/remove serdev devices via sysfs*" series
(https://www.spinics.net/lists/linux-serial/msg30732.html) but I'm not
sure if equivalent functionality exists in mainline kernel?

Is there some kind of similar hardware already supported by mainline?
Using driver as a reference might be easier than starting from
scratch.

Thanks and best regards,
								Pavel

-- 
People of Russia, stop Putin before his war on Ukraine escalates.

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Re: Cutiepi, serdevs, and right way to handle its power button

[Andy Shevchenko]

On Tue, Sep 20, 2022 at 10:56:37PM +0200, Pavel Machek wrote:
> Hi!
> 
> Cutiepie is a small handheld tablet. It has embedded controller
> connected via serial to the main system, handling stuff such as power
> button and battery percentage. Currently they are using userland
> deamon for communication, but I believe that should eventually go into
> kernel.
> 
> For debugging, it would be really nice to be able to attach my module
> to given serdev. Is such thing possible? I see "[PATCH v2 00/19]
> Dynamically load/remove serdev devices via sysfs*" series
> (https://www.spinics.net/lists/linux-serial/msg30732.html) but I'm not
> sure if equivalent functionality exists in mainline kernel?
> 
> Is there some kind of similar hardware already supported by mainline?
> Using driver as a reference might be easier than starting from
> scratch.

Is it arm or x86 based tablet?

-- 
With Best Regards,
Andy Shevchenko

Re: Cutiepi, serdevs, and right way to handle its power button

[Pavel Machek]

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On Wed 2022-09-21 17:45:33, Andy Shevchenko wrote:
> On Tue, Sep 20, 2022 at 10:56:37PM +0200, Pavel Machek wrote:
> > Hi!
> > 
> > Cutiepie is a small handheld tablet. It has embedded controller
> > connected via serial to the main system, handling stuff such as power
> > button and battery percentage. Currently they are using userland
> > deamon for communication, but I believe that should eventually go into
> > kernel.
> > 
> > For debugging, it would be really nice to be able to attach my module
> > to given serdev. Is such thing possible? I see "[PATCH v2 00/19]
> > Dynamically load/remove serdev devices via sysfs*" series
> > (https://www.spinics.net/lists/linux-serial/msg30732.html) but I'm not
> > sure if equivalent functionality exists in mainline kernel?
> > 
> > Is there some kind of similar hardware already supported by mainline?
> > Using driver as a reference might be easier than starting from
> > scratch.
> 
> Is it arm or x86 based tablet?

arm64, but CPU architecture really should not matter.

Best regards,
								Pavel
-- 
People of Russia, stop Putin before his war on Ukraine escalates.

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Re: Cutiepi, serdevs, and right way to handle its power button

[Andy Shevchenko]

On Wed, Sep 21, 2022 at 07:17:07PM +0200, Pavel Machek wrote:
> On Wed 2022-09-21 17:45:33, Andy Shevchenko wrote:
> > On Tue, Sep 20, 2022 at 10:56:37PM +0200, Pavel Machek wrote:
> > > Hi!
> > > 
> > > Cutiepie is a small handheld tablet. It has embedded controller
> > > connected via serial to the main system, handling stuff such as power
> > > button and battery percentage. Currently they are using userland
> > > deamon for communication, but I believe that should eventually go into
> > > kernel.
> > > 
> > > For debugging, it would be really nice to be able to attach my module
> > > to given serdev. Is such thing possible? I see "[PATCH v2 00/19]
> > > Dynamically load/remove serdev devices via sysfs*" series
> > > (https://www.spinics.net/lists/linux-serial/msg30732.html) but I'm not
> > > sure if equivalent functionality exists in mainline kernel?
> > > 
> > > Is there some kind of similar hardware already supported by mainline?
> > > Using driver as a reference might be easier than starting from
> > > scratch.
> > 
> > Is it arm or x86 based tablet?
> 
> arm64, but CPU architecture really should not matter.

It makes sense on the usual practices done for the platform as a whole, e.g.
ACPI vs. DT. So, I believe this one is DT based.

-- 
With Best Regards,
Andy Shevchenko