From cf18fd01466d59263c615165341684a055206dd5 Mon Sep 17 00:00:00 2001 From: Geert Uytterhoeven Date: Mon, 16 Jul 2018 17:30:52 +0200 Subject: regulator: bd9571mwv: Document "backup_mode" sysfs file MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Signed-off-by: Geert Uytterhoeven Acked-by: Pavel Machek Reviewed-by: Niklas Söderlund Signed-off-by: Mark Brown --- .../ABI/testing/sysfs-driver-bd9571mwv-regulator | 27 ++++++++++++++++++++++ 1 file changed, 27 insertions(+) create mode 100644 Documentation/ABI/testing/sysfs-driver-bd9571mwv-regulator (limited to 'Documentation/ABI') diff --git a/Documentation/ABI/testing/sysfs-driver-bd9571mwv-regulator b/Documentation/ABI/testing/sysfs-driver-bd9571mwv-regulator new file mode 100644 index 000000000000..4d63a7904b94 --- /dev/null +++ b/Documentation/ABI/testing/sysfs-driver-bd9571mwv-regulator @@ -0,0 +1,27 @@ +What: /sys/bus/i2c/devices/.../bd9571mwv-regulator.*.auto/backup_mode +Date: Jul 2018 +KernelVersion: 4.19 +Contact: Geert Uytterhoeven +Description: Read/write the current state of DDR Backup Mode, which controls + if DDR power rails will be kept powered during system suspend. + ("on"/"1" = enabled, "off"/"0" = disabled). + Two types of power switches (or control signals) can be used: + A. With a momentary power switch (or pulse signal), DDR + Backup Mode is enabled by default when available, as the + PMIC will be configured only during system suspend. + B. With a toggle power switch (or level signal), the + following steps must be followed exactly: + 1. Configure PMIC for backup mode, to change the role of + the accessory power switch from a 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 the + system. + DDR Backup Mode must be explicitly enabled by the user, + to invoke step 1. + See also Documentation/devicetree/bindings/mfd/bd9571mwv.txt. +Users: User space applications for embedded boards equipped with a + BD9571MWV PMIC. -- cgit v1.2.3