[PATCH v4 3/3] regulator: bd9571mwv: Document "backup_mode" sysfs file

Geert Uytterhoeven
2018-07-16T15:30:52Z

Acked-by: Pavel Machek <pavel@ucw.cz>
---
v4:
- Add Acked-by,

v3:
- New.
---
.../testing/sysfs-driver-bd9571mwv-regulator | 27 +++++++++++++++++++
1 file changed, 27 insertions(+)
create mode 100644 Documentation/ABI/testing/sysfs-driver-bd9571mwv-regulator

diff --git a/Documentation/ABI/testing/sysfs-driver-bd9571mwv-regulator b/Documentation/ABI/testing/sysfs-driver-bd9571mwv-regulator
new file mode 100644
index 0000000000000000..4d63a7904b94a993
--- /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 <geert+renesas@glider.be>
+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.
--
2.17.1