Hi Mark,
On Wed, Oct 18, 2017 at 1:02 PM, Mark Brown <broonie@xxxxxxxxxx> wrote:
> On Tue, Oct 10, 2017 at 05:26:17PM +0200, Geert Uytterhoeven wrote:
>> Backup mode is not enabled automatically, as e.g. on Renesas
>> Salvator-X(S) boards enabling backup mode changes the role of the ACC
>> switch from a power switch to a wake-up switch. Hence enabling it
>> prevents the board from being powered off using the ACC switch, which
>> may confuse the user.
>
> This sounds an awful lot like the standard power/wakeup, though the
> power change is a bit unexpected there. I'm also wondering if it makes
> sense to just only enable the wakeup mode when suspending which
> preserves the power off functionality while also keeping the wakeup
> support.
The ACC switch is not a momentary switch (push button), but a toggle
switch with two positions.
Hence you cannot enable wakeup mode while suspending, as the proper
system suspend/resume procedure is:
1. Enable backup mode in the PMIC,
2. Switch ACC off (no-op as backup mode has been enabled),
3. Suspend to RAM (PSCI suspend) => system suspends,
4. Switch ACC on => system wakes up.
If you would combine steps 1 and 3, you can no longer do step 2 in between.
Yes, it's complicated :-(
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
--
To unsubscribe from this list: send the line "unsubscribe devicetree" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
