Re: [PATCH v11 1/6] soc: qcom: ice: Add OPP-based clock scaling support for ICE

[Abhinaba Rakshit <abhinaba.rakshit@oss.qualcomm.com>]

On Thu, Jun 18, 2026 at 03:01:54PM +0200, Konrad Dybcio wrote:
> On 6/8/26 11:47 PM, Abhinaba Rakshit wrote:
> > Register optional operation-points-v2 table for ICE device
> > during device probe. Attach the OPP-table with only the ICE
> > core clock. Since, dtbinding is on a transition phase to include
> > iface clock and clock-names, attaching the opp-table to core clock
> > remains optional such that it does not cause probe failures.
> > 
> > Introduce clock scaling API qcom_ice_scale_clk which scale ICE
> > core clock based on the target frequency provided and if a valid
> > OPP-table is registered. Use round_ceil passed to decide on the
> > rounding of the clock freq against OPP-table. Clock scaling is
> > disabled when a valid OPP-table is not registered.
> > 
> > This ensures when an ICE-device specific OPP table is available,
> > use the PM OPP framework to manage frequency scaling and maintain
> > proper power-domain constraints.
> > 
> > Also, ensure to drop the votes in suspend to prevent power/thermal
> > retention. Subsequently restore the frequency in resume from
> > core_clk_freq which stores the last ICE core clock operating frequency.
> > 
> > Reviewed-by: Harshal Dev <harshal.dev@oss.qualcomm.com>
> > Signed-off-by: Abhinaba Rakshit <abhinaba.rakshit@oss.qualcomm.com>
> > ---
> 
> [...]
> 
> > @@ -335,6 +342,11 @@ int qcom_ice_suspend(struct qcom_ice *ice)
> >  {
> >  	clk_disable_unprepare(ice->iface_clk);
> >  	clk_disable_unprepare(ice->core_clk);
> > +
> > +	/* Drop the clock votes while suspend */
> > +	if (ice->has_opp)
> > +		dev_pm_opp_set_rate(ice->dev, 0);
> 
> The PM core will quiesce the vote as the device suspends, this is
> unnecessary. Similarly, the rate restore logic will become unnecessary.
> Especially since dev_pm_opp_set_rate(0) does not actually do any rate
> setting.

This section was earlier discussed in the patchset v4:
https://lore.kernel.org/all/7b219a50-6971-4a0c-a465-418f8abd5556@oss.qualcomm.com/
The intention here was to drop the RPMh votes once the device goes to suspend same
as the storage drivers such as mmc drivers does:
https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/tree/drivers/mmc/host/sdhci-msm.c#n2946
This was done to leave the hanging votes *on* for unused clocks.

However, I get your point, due to mean to say that once device goes to suspend
and GDSC power-domain will be turned OFF, it will automatically quiesce the
performance votes?

Abhinaba Rakshit