linux-kernel - Re: [PATCH v2 2/5] clk: scmi: Add support for state control restricted clocks

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Date: Mon, 8 Apr 2024 19:26:09 +0100
From: Cristian Marussi <cristian.marussi@....com>
To: Stephen Boyd <sboyd@...nel.org>
Cc: linux-arm-kernel@...ts.infradead.org, linux-clk@...r.kernel.org,
	linux-kernel@...r.kernel.org, sudeep.holla@....com,
	james.quinlan@...adcom.com, f.fainelli@...il.com,
	vincent.guittot@...aro.org, peng.fan@....nxp.com,
	michal.simek@....com, quic_sibis@...cinc.com,
	quic_nkela@...cinc.com, souvik.chakravarty@....com,
	mturquette@...libre.com
Subject: Re: [PATCH v2 2/5] clk: scmi: Add support for state control
 restricted clocks

On Sun, Apr 07, 2024 at 09:48:59PM -0700, Stephen Boyd wrote:
> Quoting Cristian Marussi (2024-03-25 14:00:22)
> > Some exposed SCMI Clocks could be marked as non-supporting state changes.
> > Configure a clk_ops descriptor which does not provide the state change
> > callbacks for such clocks when registering with CLK framework.
> > 
> > CC: Michael Turquette <mturquette@...libre.com>
> > CC: Stephen Boyd <sboyd@...nel.org>
> > CC: linux-clk@...r.kernel.org
> > Signed-off-by: Cristian Marussi <cristian.marussi@....com>
> > ---
> >  drivers/clk/clk-scmi.c | 22 +++++++++++++++-------
> >  1 file changed, 15 insertions(+), 7 deletions(-)
> > 
> > diff --git a/drivers/clk/clk-scmi.c b/drivers/clk/clk-scmi.c
> > index d5d369b052bd..fc9603988d91 100644
> > --- a/drivers/clk/clk-scmi.c
> > +++ b/drivers/clk/clk-scmi.c
> > @@ -18,6 +18,7 @@
> >  
> >  enum scmi_clk_feats {
> >         SCMI_CLK_ATOMIC_SUPPORTED,
> > +       SCMI_CLK_STATE_CTRL_FORBIDDEN,
> 
> Can it be positive, i.e. SCMI_CLK_STATE_CTRL_SUPPORTED?

Yes of course.

> 
> >         SCMI_CLK_MAX_FEATS
> >  };
> >  
> > @@ -230,15 +231,19 @@ scmi_clk_ops_alloc(struct device *dev, unsigned long feats_key)
> >          * only the prepare/unprepare API, as allowed by the clock framework
> >          * when atomic calls are not available.
> >          */
> > -       if (feats_key & BIT(SCMI_CLK_ATOMIC_SUPPORTED)) {
> > -               ops->enable = scmi_clk_atomic_enable;
> > -               ops->disable = scmi_clk_atomic_disable;
> > -               ops->is_enabled = scmi_clk_atomic_is_enabled;
> > -       } else {
> > -               ops->prepare = scmi_clk_enable;
> > -               ops->unprepare = scmi_clk_disable;
> > +       if (!(feats_key & BIT(SCMI_CLK_STATE_CTRL_FORBIDDEN))) {
> > +               if (feats_key & BIT(SCMI_CLK_ATOMIC_SUPPORTED)) {
> > +                       ops->enable = scmi_clk_atomic_enable;
> > +                       ops->disable = scmi_clk_atomic_disable;
> > +               } else {
> > +                       ops->prepare = scmi_clk_enable;
> > +                       ops->unprepare = scmi_clk_disable;
> > +               }
> >         }
> >  
> > +       if (feats_key & BIT(SCMI_CLK_ATOMIC_SUPPORTED))
> > +               ops->is_enabled = scmi_clk_atomic_is_enabled;
> > +
> >         /* Rate ops */
> >         ops->recalc_rate = scmi_clk_recalc_rate;
> >         ops->round_rate = scmi_clk_round_rate;
> > @@ -288,6 +293,9 @@ scmi_clk_ops_select(struct scmi_clk *sclk, bool atomic_capable,
> >         if (atomic_capable && ci->enable_latency <= atomic_threshold)
> >                 feats_key |= BIT(SCMI_CLK_ATOMIC_SUPPORTED);
> >  
> > +       if (ci->state_ctrl_forbidden)
> 
> Then this is negated.
> 

I will rework accordingly

Thanks,
Cristian