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31 lines
1.3 KiB
31 lines
1.3 KiB
What: /sys/bus/i2c/devices/.../bd9571mwv-regulator.*.auto/backup_mode |
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Date: Jul 2018 |
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KernelVersion: 4.19 |
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Contact: Geert Uytterhoeven <[email protected]> |
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Description: Read/write the current state of DDR Backup Mode, which controls |
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if DDR power rails will be kept powered during system suspend. |
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("on"/"1" = enabled, "off"/"0" = disabled). |
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Two types of power switches (or control signals) can be used: |
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A. With a momentary power switch (or pulse signal), DDR |
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Backup Mode is enabled by default when available, as the |
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PMIC will be configured only during system suspend. |
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B. With a toggle power switch (or level signal), the |
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following steps must be followed exactly: |
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1. Configure PMIC for backup mode, to change the role of |
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the accessory power switch from a power switch to a |
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wake-up switch, |
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2. Switch accessory power switch off, to prepare for |
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system suspend, which is a manual step not controlled |
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by software, |
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3. Suspend system, |
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4. Switch accessory power switch on, to resume the |
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system. |
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DDR Backup Mode must be explicitly enabled by the user, |
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to invoke step 1. |
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See also Documentation/devicetree/bindings/mfd/bd9571mwv.txt. |
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Users: User space applications for embedded boards equipped with a |
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BD9571MWV PMIC.
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