From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pavel Machek Subject: Re: [PATCH v3 0/3] regulator: bd9571mwv: Add support for toggle power switches Date: Sun, 15 Jul 2018 18:57:49 +0200 Message-ID: <20180715165749.GA10023@amd> References: <20180713154720.18316-1-geert+renesas@glider.be> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="wRRV7LY7NUeQGEoC" Return-path: Content-Disposition: inline In-Reply-To: <20180713154720.18316-1-geert+renesas@glider.be> Sender: linux-kernel-owner@vger.kernel.org To: Geert Uytterhoeven Cc: Marek Vasut , Liam Girdwood , Mark Brown , "Rafael J . Wysocki" , Len Brown , linux-pm@vger.kernel.org, linux-renesas-soc@vger.kernel.org, linux-kernel@vger.kernel.org List-Id: linux-pm@vger.kernel.org --wRRV7LY7NUeQGEoC Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable 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. >=20 > 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. >=20 > 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,=20 > 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. >=20 > 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. >=20 > This patch series allows performing step 1 when the user writes > "on" to the PMIC's "backup_mode" virtual file in sysfs, e.g. >=20 > echo on > /sys/bus/i2c/drivers/bd9571mwv/*/bd9571mwv-regulator*/backu= p_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 --=20 (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blo= g.html --wRRV7LY7NUeQGEoC Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iEYEARECAAYFAltLfQ0ACgkQMOfwapXb+vILOgCbBFGjbwH2cufstj+Q+5TXiYPW +OcAn27r+67d8CbVJRQrRJLTuI0tcHyA =OScm -----END PGP SIGNATURE----- --wRRV7LY7NUeQGEoC--