Hi Miguel,
Am 22.12.19 um 00:12 schrieb Miguel Ojeda:
On Sat, 21 Dec 2019 at 22:49 Andreas Färber <afaerber@xxxxxxx
<mailto:afaerber@xxxxxxx>> wrote:
Hi,
Am 21.12.19 um 22:04 schrieb Pavel Machek:
>>>> Allow to squeeze the text "HEllO" into a 4-digit display,
>>>> as seen on MeLE V9 TV box.
>>>>
>>>> Enable this combining mode only if the text would overflow.
>>>
>>> "HEll,nO"!
>>>
>>> :-)
>>>
>>> Ok, it is kind of cool, but... Can you take a look at
>>> drivers/auxdisplay/charlcd.c ? It seems to support some kind of
text
>>> displays...
>>
>> Why don't you look at it before making such a suggestion? ;) It
is in no way
>> useful, as I pointed out in my cover letter. The only thing
related today,
>> as Geert pointed out, is in the input subsystem.
>
> Okay, so maybe we should get
>
> AUXILIARY DISPLAY DRIVERS
> M: Miguel Ojeda Sandonis <miguel.ojeda.sandonis@xxxxxxxxx
<mailto:miguel.ojeda.sandonis@xxxxxxxxx>>
>
> on the Cc: list?
Let's see if that email still exists - the code looked ancient, full of
platform_data and driver-specific exported functions...
(the Yealink input driver was from 2005, too)
The code may look ancient, but the email surely exists ;)
> What you really have is a display, not a bunch of LEDs.
We have an LED Controller connected to zero, one or more displays.
They are most certainly _not_ the same thing.
>> If you don't want this in leds, you'll have to help make leds
subsystem more
>> useful to external users - the latest function refactoring has
been anything
>> but helpful here, as you've seen with the indicators, and we're
completely
>> lacking any indexing or bulk operations on the LED controller
level, since
>> you treat each LED as a standalone device. That's precisely why
this code is
>> here in leds although - as I pointed out - it shouldn't belong here.
>
> Well, your introduction mail was kind of long :-).
>
> If someone wants to do heartbeat on
>
> --
> | | <- this segment
> --
> | |
> --
>
> they are probably crazy. We may not want to support that. What about
> doing it as auxdisplay driver, and then exporting the indicators
> around that as LEDs?
You're really just discussing which directory to put this file into -
moving it around is the easiest thing...
>
> Having USB activity trigger on 'USB' icon makes sense, on the other
> hand. That would still be supported.
Actually I disagree about those indicators - that was the reason
they're
indicators and not, e.g., "usb". IMO people would go crazy if large
text
like that blinked during USB transfers. I assumed the meaning of those
LEDs were to indicate whether a USB/SD medium is connected, which I did
not see any better function for, and I'm not aware of us having such
triggers today.
Maybe you also overread that with trigger I was referring to using RTC
as trigger for a) the colon blinking every half-second and b) the text
getting updated based on avsilable RTC interrupts?
You could also think of GPIO-connected LEDs that you may want to
animate
without two different heartbeats/timers getting out of sync. Or
think of
an RGB LED that today we sadly need to model as multiple GPIO LEDs
instead of as one with a color property we can change (and hardcoding a
color in DT/name is not helping that use case either).
auxdisplay offers no API that I could register with to drive output,
nor
any triggers to automate such output - that's unique to LEDs. Like I
said, we can place this spi_driver file into auxdisplay/, but that
doesn't solve the driver design.
I think it would be alright to put it in auxdisplay.
Please find the full series on, e.g., LAKML:
https://patchwork.kernel.org/cover/11286939/
So I really think we need to decouple
the two and keep the LED Controller driver in leds and the display
logic
elsewhere, with suitable new APIs to connect them. We're lacking
suggestions for the how, on DT and API levels - see my response on
[...]the
cover letter.
As explained in the cover letter, the problem here is that I don't know
the model or manufacturer of these unmarked white-plastic-frame LED
displays. So we have neither a filename to use in auxdisplay/ nor a DT
compatible string to use for those displays.
Cheers,
Andreas
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