[PATCH 0/7] misc: introduce STATUS LED activity function

[Christian Marangi]

On Thu, Jun 06, 2024 at 11:12:11AM +0200, Quentin Schulz wrote:
> Hi Christian,
> 
> On 6/5/24 9:21 PM, Christian Marangi wrote:
> > This series expand the STATUS LED framework with a new color
> > and a big new feature. One thing that many device need is a way
> > to communicate to the user that the device is actually doing
> > something.
> > 
> > This is especially useful for recovery steps where an
> > user (for example) insert an USB drive, keep a button pressed
> > and the device autorecover.
> > 
> > There is currently no way to signal the user externally that
> > the bootloader is processing/recoverying aside from setting
> > a LED on.
> > 
> > A solid LED on is not enough and won't actually signal any
> > kind of progress.
> > Solution is the good old blinking LED but uboot doesn't
> > suggest (and support) interrupts and almost all the LED
> > are usually GPIO LED that doesn't support HW blink.
> > 
> 
> I haven't used it yet but we do have a cyclic framework now for things
> happening in the background. I think this is a good use-case for this
> framework? Something would set the blinking frequency (could be from CLI
> directly, or as part of board files, or architecture, etc...) and the LED
> would just blink then. This would allow to highlight stages in the boot
> process, though that is not like an activity LED so if you're stuck in a
> stage, you wouldn't know if something is still happening or if you're really
> stuck (e.g. no packet on TFTP or TFTP very slow). The benefit is that it
> would be way less intrusive than patching all commands that could make use
> of that LED. Right now, this only adds support to MTD, SPI and TFTP, but
> what about MMC, NVMe, USB, other net stuff (e.g. wget), etc...
>

Can you hint me on where is this framework? Checking the tftp code i
couldn't find extra call to it. Maybe it's attached to the schedule()
function?

Also notice that it's really not a one setting since almost all device
have GPIO LEDs and doesn't have a way to support HW Blink so the
"activity" function needs to be called multiple time to increase the
counter and toggle the LED.

Also this have the extra feature that you can check if something gets
stuck in the process. The lifecycle is:
- Turn on the ACTIVITY LED at the start of the thing
- Blink once in a while (for very little task this might not happen)
- Turn off the ACTIVITY LED at the end of the thing

Soo if something goes wrong the LED would never turn OFF but would stay
solid ON.

More than happy to rework this to a less intrusive implementation.

Maybe this can be generalized to some generic API like task_start(),
task_processing() and task_end()? Might make more sense than having to
add specific LED function to each function?

(AFAIK linux kernel have something similar used for all the trace
framework so having something in uboot to trace these kind of operation
might be interesting)

-- 
	Ansuel