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SubjectRe: [PATCH v3 0/3] regulator: bd9571mwv: Add support for toggle power switches

> 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.
> 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.
> 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,
> 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.
> 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.
> This patch series allows performing step 1 when the user writes
> "on" to the PMIC's "backup_mode" virtual file in sysfs, e.g.
> echo on > /sys/bus/i2c/drivers/bd9571mwv/*/bd9571mwv-regulator*/backup_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...?


(cesky, pictures)
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