From: Pavel Machek <pavel@ucw.cz>
To: Thierry Reding <thierry.reding@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
"Rafael J . Wysocki" <rjw@rjwysocki.net>,
Sebastian Reichel <sre@kernel.org>,
Guenter Roeck <linux@roeck-us.net>,
linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [RFC 1/3] system-power: Add system power and restart framework
Date: Wed, 1 Feb 2017 12:13:31 +0100 [thread overview]
Message-ID: <20170201111331.GA27721@amd> (raw)
In-Reply-To: <20170131174658.GA16896@ulmo.ba.sec>
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On Tue 2017-01-31 18:46:58, Thierry Reding wrote:
> On Mon, Jan 30, 2017 at 10:53:01PM +0100, Pavel Machek wrote:
> > Hi!
> >
> >
> > > +struct system_power_chip;
> > > +
> > > +struct system_power_ops {
> > > + int (*restart)(struct system_power_chip *chip, enum reboot_mode mode,
> > > + char *cmd);
> > > + int (*power_off_prepare)(struct system_power_chip *chip);
> > > + int (*power_off)(struct system_power_chip *chip);
> > > +};
> > > +
> > > +struct system_power_chip {
> > > + const struct system_power_ops *ops;
> > > + struct list_head list;
> > > + struct device *dev;
> > > +};
> >
> > Is it useful to have two structures? AFAICT one would do.
>
> Yeah, one structure works fine. I was drawing inspiration from other
> subsystems that have a separate structure for these. I've merged the
> operations into the struct system_power_chip now because that gives
> us some more flexiblity, for example in cases where a chip can be a
> power controller and a reset controller, but sometimes we may want
> it to be only one of them.
>
> > Do we always have struct device * to work with? IMO we have nothing
> > suitable for example in the ACPI case. Would void * be more suitable?
>
> The struct device * was meant to be purely optional, but working with
> the code some more today and doing some more conversions, I've resorted
> to adding a separate field (const char *name) that takes precedence. So
> if a chip specifies both a .dev and .name field, then .name will be the
> user visible string, otherwise dev_name(.dev) will be used in
> messages.
Thanks!
> > Could you convert someting (acpi?) to the new framework as
> > demonstration?
>
> I had originally only converted architecture code to call into system
> power instead of the notifier chain and added a driver for a chip that
> I want to get this to work on. I've now converted a couple of other
> drivers from drivers/power/reset as well as ACPI. I've also added a
> very rudimentary prioritization mechanism that I've validated on the
> specific setup that I'm working on.
>
> On the Jetson TX1 that I'm testing this on, the SoC has a way of
> resetting itself. This has the advantage that some of the registers are
> kept intact over the reset, and this in turn is used to control early
> boot, so that specific recovery modes can be used. However, the board
> has to be powered off using the PMIC (via I2C). The patches achieve this
> by splitting up restart and power off into two steps, prepare and
> restart/power-off, as well as levels to prioritize. On Jetson TX1 the
> PMIC will be higher priority than the SoC (determined by the level) and
> therefore be able to override the SoC restart mechanism if we want to.
> If we don't we simply instruct the MAX77620 driver not to register the
> restart callback, in which case the SoC implementation will be used.
>
> I've uploaded all of it to a branch on github:
>
> https://github.com/thierryreding/linux/tree/system-power
>
> It's rather lengthy, so I'm not sure if it makes sense to send to the
> lists right away.
It is easier to review on lists, but no reasons to do it now.
Pavel
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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next prev parent reply other threads:[~2017-02-01 11:13 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-01-30 17:15 [RFC 0/3] Add system power and restart framework Thierry Reding
2017-01-30 17:15 ` [RFC 1/3] system-power: " Thierry Reding
2017-01-30 21:53 ` Pavel Machek
2017-01-31 17:46 ` Thierry Reding
2017-02-01 11:13 ` Pavel Machek [this message]
2017-01-30 17:15 ` [RFC 2/3] kernel: Wire up system power framework Thierry Reding
2017-01-30 17:15 ` [RFC 3/3] PM / hibernate: Wire up system-power framework Thierry Reding
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