Hello all,
I'm trying to use the regulator framework in conjunction with suspend/resume
(code based on a s3c Samsung SoC platform).
My goal is to change values of regulators output before going to sleep and
restore their values after resume.
I use echo mem > /sys/power/state to suspend to RAM.
I've implemented platform_suspend_ops' .begin method and from it I'm calling
the regulator_suspend_prepare(state) function from regulator framework
(declared at include/linux/regulator/machine.h, defined at core.c).
After this step I'm going to sleep. And it seems that voltage values are
changed/disabled as they should (according to .constraints->.state_mem
struct fields).
The problem is when I disable normally enabled source or change its voltage
value to new_value when entering the suspend to RAM state.
.state_mem = {
.enabled= 0,
},
Or
.state_mem = {
.uV= new_value,
.enabled= 1,
},
I don't know how to enable this source again after resume or restore source
microvolts setting as before suspend?
As I suppose, the preferred place for performing this would be a .finish
method from platform_suspend_ops' structure (declared in
include/linux/suspend.h).
It looks like some relevant method is missing in the framework, or I haven't
look deep enough to spot one :-).
One possible workaround would be to reinitialize all regulators with
regulator_init_complete(void) function, but I'm not sure if then old
microvolt settings would be restored. Probably not...
Does anybody have any idea how to solve this problem?
I was grepping a little and it looks, that regulator_suspend_prepare()
method is not used by any suspend/resume driver in the kernel linux tree (at
least up to kernel version 2.6.32-rc8), so there is no reference code.
Thanks in advance,
Lukasz Majewski
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