On 8/31/2022 3:05 AM, Stephen Boyd wrote:
Quoting Rajendra Nayak (2022-08-29 01:12:02)
diff --git a/drivers/clk/qcom/gdsc.c b/drivers/clk/qcom/gdsc.c
index d3244006c661..0fe017ba901b 100644
--- a/drivers/clk/qcom/gdsc.c
+++ b/drivers/clk/qcom/gdsc.c
@@ -368,6 +368,10 @@ static int _gdsc_disable(struct gdsc *sc)
if (sc->pwrsts & PWRSTS_OFF)
gdsc_clear_mem_on(sc);
+ /* If the GDSC supports RET, do not explicitly power it off */
+ if (sc->pwrsts & PWRSTS_RET)
+ return 0;
+
ret = gdsc_toggle_logic(sc, GDSC_OFF);
if (ret)
return ret;
So with that change, we would then not need the ALWAYS_ON flag set for usb gdsc,
instead we would update the .pwrsts to PWRSTS_RET_ON instead of PWRSTS_OFF_ON,
and that should make both usb wake-ups to work and we can still have the usb_gdsc as
a subdomain of CX for performance state voting.
To clarify, usb_gdsc is not setup as a subdomain of CX so far, right?
Just that eventually we'll make usb_gdsc a subdomain of CX so that
dev_pm_opp_set_rate() can target the CX domain instead of the usb one?
Thats right,
Does that sounds like a reasonable solution?
It sounds good to me. What about the existing users of PWRSTS_RET
hmm, I thought no ones been actually using PWRSTS_RET but looks like
there is *one* user on msm8974, I'll need to dig up how this change would
affect it,
though? If I understand correctly this flag means the domain will never
be turned off, instead it will hit retention during low power modes.
right,
While you're crafting this patch can you also document the PWRSTS_*
defines so that we know what they mean? I can guess that PWRSTS_RET
means "retention" but I don't know what it really means. I guess it
means "Deepest power off state is retention of memory cells".
Sure I will update the PWRSTS_RET description. The definition of 'retention'
here I think remains the same, it means memory is retained (if RETAIN_MEM is set)
or memory *and* some part of logic is retained (if both RETAIN_MEM and RETAIN_PERIPH
are set) in Deepest power off state, however there is a disconnected in terms of
'how to enter the retention state' for a given domain.
There is no SW control to enter the retention state and this happens in HW when the
parent domain/rail transitions to low power. Either the parents lowest power state
is also retention (like is the case with sc7180/sc7280 for usb with cx as parent) or the
parent makes sure it hands the domain over to another parent (CX to MX in some cases)
to support retention.
