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| -rw-r--r-- | Documentation/ABI/testing/sysfs-driver-bd9571mwv-regulator | 27 |
1 files changed, 27 insertions, 0 deletions
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 <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. |