Hi Mark, On 12.12.2018 17:55, Mark Brown wrote: > On Wed, Dec 12, 2018 at 08:01:07AM +0000, andrei.stefane...@microchip.com > wrote: > >>> This puts the device into low power mode when the suspend function gets >>> called but this might not be safe - devices using the regulator may not >>> be suspended yet so could still need full regulation. Normally a GPIO >>> triggered transition like this would be being done by hardware as part >>> of the process of suspending the SoC. Is there some reason to do this >>> manually? >> There is a line from the MPU (SHDN) which goes low only when the MPU >> turns off. That line is already connected to the PMIC and it differentiates >> between suspend-to-mem and standby. To switch to low-power, the PMIC must >> be controlled by the GPIO pin LPM. >> The suspend sequence is: >> - LPM pin goes high (PMIC enters Low-Power <-> Linux standby) >> - SHDN goes low (if target suspend state is mem) and then PMIC enters >> HIBERNATE > This feels like it should be being controlled somewhere else, if it's > actually causing a change in the PMIC state it seems like it wants to be > done as late as possible in suspend to minimize the risks. At the very > least suspend_late() for the driver seems appropriate. I tried with both suspend_late/resume_early and suspend_noirq/resume_noirq. Everything seems to work ok.
Which one do you think is more appropriate? I am guessing that during suspend_late some devices may still need to be turned on and that it would be the safest during suspend_noirq. Note: the GPIO pin used for LPM is a special one (it maintains its voltage during suspend-to-mem). It is part of the SoC and its methods for setting the values do not sleep. > > Could you submit a version with this feature at least split out into a > separate patch please so we can apply the rest of the code while this is > discussed? Sent one patch series and another patch with the current suspend/resume implementation. Best regards, Andrei
