linux-kernel - Re: [PATCH v1 3/6] leds: Add driver for Acer Iconia Tab A500

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Message-ID: <c7d37174-1dcd-206d-01ac-eb95aa0b5dc8@gmail.com>
Date:   Mon, 24 Aug 2020 13:16:56 +0300
From:   Dmitry Osipenko <digetx@...il.com>
To:     Pavel Machek <pavel@....cz>
Cc:     Lee Jones <lee.jones@...aro.org>, Rob Herring <robh+dt@...nel.org>,
        Thierry Reding <thierry.reding@...il.com>,
        Jonathan Hunter <jonathanh@...dia.com>,
        Dan Murphy <dmurphy@...com>,
        Sebastian Reichel <sre@...nel.org>,
        Lubomir Rintel <lkundrak@...sk>, devicetree@...r.kernel.org,
        linux-tegra@...r.kernel.org, linux-leds@...r.kernel.org,
        linux-pm@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v1 3/6] leds: Add driver for Acer Iconia Tab A500

24.08.2020 01:34, Pavel Machek пишет:
> On Sun 2020-08-23 17:08:43, Dmitry Osipenko wrote:
>> Acer Iconia Tab A500 is an Android tablet device which has two LEDs
>> embedded into the Power Button. Orange LED indicates "battery charging"
>> status and white LED indicates "wake-up/charge-done" status. The new LED
>> driver provides control over both LEDs to userspace.
> 
> Hmm. If the ENE controller is similar to other devices, should it also
> share LED driver?
> 
> And I guess the cdev names should be different based on info above (I
> gave you wrong suggestions before)... and they probably should be
> parsed from the device tree.

The ENE controller hardware is the same on all devices that use it, but
firmware isn't the same and apparently every vendor invents its own
thing in regards to the firmware because firmware features and interface
varies vastly from device to device. Hence, unfortunately, usually there
is very little compatibility even if devices come form the same vendor

AFAIK, the ENE controller provides some compatibility on x86 machines
via ACPI EC standard, but this doesn't apply to the ARM devices.

I know that Acer A200 should be able to re-use the A500 EC driver as-is,
but A200 is pretty much the same device as A500, so it's not surprising.
IIRC, A200 model only misses back camera in comparison to A500. Hence
there shouldn't be a need to parse the names from a device-tree, but
I'll try to double-check it to be sure.

Thanks!