Re: [PATCH 2/3] pmdomain: spacemit: Add power domain driver

[Icenowy Zheng]

在 2026-09-21一的 03:35 +0000，Yixun Lan写道：
> Hi Icenowy,
> 
> On 20:56 Sun 20 Sep     , Icenowy Zheng wrote:
> > 在 2026-09-18五的 02:40 +0000，Yixun Lan写道：
> > >   SpacemiT's PMU (Power Management Unit) consist of several power
> > > domains
> > > which can be managed independently, depending on different
> > > application
> > > scenario, each domain can be powered on/off for saving power.
> > > 
> > >   The driver is implemented based on Linux Generic PM Domain
> > > framework.
> > > From a hardware perspective, either of two distinct power-on
> > > sequences
> > > are supported, in software mode (SW mode), the driver is
> > > responsible
> > > for
> > > controlling the states of bits such as sleep1, sleep2, isolation
> > > and
> > > pwr_state, while in hardware mode (HW mode), the PMU hardware
> > > will
> > > complete
> > > the sequence automatically without requiring software
> > > intervention.
> > 
> > This driver is tested to be able to power up the GPU on SpacemiT
> > K3,
> > however the following warning appears in the kernel log:
> > 
> > ```
> > genpd_provider audio: Fail to power-off domain: 2
> > ```
> > 
> This is kind of an expected issue, due to hardware design, the audio
> power switch is coupled with rcpu core, which means power off it will
> also shut down the rcpu, so the power switch currently is configured
> as always on from software perspective, it's unable to power-off even
> in Linux or rcpu once system up.

Should the GENPD_FLAG_ALWAYS_ON flag be applied onto this power domain
if it's not meant to be shut down?

Thanks,
Icenowy

> 
> I will drop audio power domain control in next version
> 
> > (BTW I built it as a module to prevent whole kernel being rebuilt)
> > 
> that's fine