[PATCH v5 5/5] drm/msm/disp/dpu1: set mdp clk to the maximum frequency in opp table during probe

[Vinod Polimera]

> -----Original Message-----
> From: Dmitry Baryshkov <dmitry.baryshkov at linaro.org>
> Sent: Tuesday, March 8, 2022 10:40 PM
> To: quic_vpolimer <quic_vpolimer at quicinc.com>
> Cc: dri-devel at lists.freedesktop.org; linux-arm-msm at vger.kernel.org;
> freedreno at lists.freedesktop.org; devicetree at vger.kernel.org; linux-
> kernel at vger.kernel.org; robdclark at gmail.com; dianders at chromium.org;
> swboyd at chromium.org; quic_kalyant <quic_kalyant at quicinc.com>
> Subject: Re: [PATCH v5 5/5] drm/msm/disp/dpu1: set mdp clk to the
> maximum frequency in opp table during probe
> 
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> 
> On Tue, 8 Mar 2022 at 19:55, Vinod Polimera <quic_vpolimer at quicinc.com>
> wrote:
> >
> > use max clock during probe/bind sequence from the opp table.
> > The clock will be scaled down when framework sends an update.
> >
> > Signed-off-by: Vinod Polimera <quic_vpolimer at quicinc.com>
> > ---
> >  drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c | 3 +++
> >  1 file changed, 3 insertions(+)
> >
> > diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c
> b/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c
> > index d550f90..d9922b9 100644
> > --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c
> > +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c
> > @@ -1221,6 +1221,7 @@ static int dpu_bind(struct device *dev, struct
> device *master, void *data)
> >         struct dpu_kms *dpu_kms;
> >         struct dss_module_power *mp;
> >         int ret = 0;
> > +       unsigned long max_freq = ULONG_MAX;
> >
> >         dpu_kms = devm_kzalloc(&pdev->dev, sizeof(*dpu_kms),
> GFP_KERNEL);
> >         if (!dpu_kms)
> > @@ -1243,6 +1244,8 @@ static int dpu_bind(struct device *dev, struct
> device *master, void *data)
> >                 return ret;
> >         }
> >
> > +       dev_pm_opp_find_freq_floor(dev, &max_freq);
> 
> You leak a reference to the opp here. The function returns a value,
> which should be dev_pm_opp_put().
> Moreover judging from the dev_pm_opp_set_rate() code I think you don't
> have to find an exact frequency, as it will call
> clk_round_rate()/_find_freq_ceil() anyway.
> Could you please check that it works?

clk_round_rate  will get the max frequency in freq_table in clk driver and if that frequency is missing in opp
table it will throw error. So, It will be optimal to get max freq in opp table and set it based on that freq.
> 
> > +       dev_pm_opp_set_rate(dev, max_freq);
> >         platform_set_drvdata(pdev, dpu_kms);
> >
> >         ret = msm_kms_init(&dpu_kms->base, &kms_funcs);
> > --
> > 2.7.4
> >
> 
> 
> --
> With best wishes
> Dmitry