From: Pavel Machek <pavel@ucw.cz>
To: Geert Uytterhoeven <geert+renesas@glider.be>
Cc: Marek Vasut <marek.vasut+renesas@gmail.com>,
Liam Girdwood <lgirdwood@gmail.com>,
Mark Brown <broonie@kernel.org>,
"Rafael J . Wysocki" <rjw@rjwysocki.net>,
Len Brown <len.brown@intel.com>,
linux-pm@vger.kernel.org, linux-renesas-soc@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3 0/3] regulator: bd9571mwv: Add support for toggle power switches
Date: Sun, 15 Jul 2018 18:57:49 +0200 [thread overview]
Message-ID: <20180715165749.GA10023@amd> (raw)
In-Reply-To: <20180713154720.18316-1-geert+renesas@glider.be>
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Hi!
> The ROHM BD9571MWV PMIC on the Renesas Salvator-X(S) and ULCB
> development boards supports DDR Backup Power, which means that the DDR
> power rails can be kept powered while the main SoC is powered down.
>
> This patch series extends the support for DDR backup mode (see commit
> 6eb0bfae6973eb6a ("regulator: bd9571mwv: Add support for backup mode"))
> to systems with toggle instead of momentary power switches.
>
> With a toggle power switch (or level signal), the following steps must
> be followed exactly:
> 1. Configure PMIC for backup mode, which changes the role of the
> power switch to a wake-up switch,
> 2. Switch accessory power switch off, to prepare for system suspend,
> which is a manual step not controlled by software,
> 3. Suspend system,
> 4. Switch accessory power switch on, to resume.
>
> Unlike on systems with a momentary toggle switch, an additional step 2
> must be performed in between step 1 and step 3. Hence step 1 can no
> longer be handled in the PMIC's suspend callback.
>
> This patch series allows performing step 1 when the user writes
> "on" to the PMIC's "backup_mode" virtual file in sysfs, e.g.
>
> echo on > /sys/bus/i2c/drivers/bd9571mwv/*/bd9571mwv-regulator*/backup_mode
Do you expect more boards to have similar design?
If so, we may want to have standard place in /sys/ not depending on
i2c paths and driver names, but I believe such design is so... awkward
that it is not going to appear anywhere else...?
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:[~2018-07-15 16:59 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-07-13 15:47 [PATCH v3 0/3] regulator: bd9571mwv: Add support for toggle power switches Geert Uytterhoeven
2018-07-13 15:47 ` [PATCH v3 1/3] regulator: bd9571mwv: Use "backup_mode" sysfs file instead of "wake_up" Geert Uytterhoeven
2018-07-13 20:08 ` Geert Uytterhoeven
2018-07-13 15:47 ` [PATCH v3 2/3] regulator: bd9571mwv: Add support for toggle power switches Geert Uytterhoeven
2018-07-13 15:47 ` [PATCH v3 3/3] regulator: bd9571mwv: Document "backup_mode" sysfs file Geert Uytterhoeven
2018-07-15 16:59 ` Pavel Machek
2018-07-15 16:57 ` Pavel Machek [this message]
2018-07-16 8:58 ` [PATCH v3 0/3] regulator: bd9571mwv: Add support for toggle power switches Geert Uytterhoeven
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