Re: [PATCH] drm/msm/dp: add voltage corners voting support base on dp link rate

[Rajendra Nayak]

On 9/30/2020 1:54 PM, Stephen Boyd wrote:
> Quoting Kuogee Hsieh (2020-09-29 10:10:26)
> > Set link rate by using OPP set rate api so that CX level will be set
> > accordingly base on the link rate.
>
> s/base/based/
>
> > Signed-off-by: Kuogee Hsieh <khsieh@xxxxxxxxxxxxxx>
> > ---
> > diff --git a/drivers/gpu/drm/msm/dp/dp_ctrl.c b/drivers/gpu/drm/msm/dp/dp_ctrl.c
> > index 2e3e1917351f..e1595d829e04 100644
> > --- a/drivers/gpu/drm/msm/dp/dp_ctrl.c
> > +++ b/drivers/gpu/drm/msm/dp/dp_ctrl.c
> > @@ -1849,6 +1853,21 @@ struct dp_ctrl *dp_ctrl_get(struct device *dev, struct dp_link *link,
> >                  return ERR_PTR(-ENOMEM);
> >          }
> >   
> > +       ctrl->opp_table = dev_pm_opp_set_clkname(dev, "ctrl_link");

I see that downstream has multiple DP clocks which end up voting on CX, we don't have a
way of associating multiple OPP tables with a device upstream, so whats usually done is
(assuming all the clocks get scaled in lock step, which I assume is the case here) we pick
the clock with the 'highest' CX requirement and associate that with the OPP table.
I haven't looked but I am hoping thats how we have decided to associate "ctrl_link" clock
here?

> > +
> > +       if (IS_ERR(ctrl->opp_table)) {
> > +               dev_err(dev, "invalid DP OPP table in device tree\n");
> > +               ctrl->opp_table = NULL;
> > +       } else {
> > +               /* OPP table is optional */
> > +               ret = dev_pm_opp_of_add_table(dev);
> > +               if (ret && ret != -ENODEV) {
> > +                       dev_err(dev, "add DP OPP table\n");
>
> This is debug noise right?
>
> > +                       dev_pm_opp_put_clkname(ctrl->opp_table);
> > +                       ctrl->opp_table = NULL;
> > +               }
> > +       }
> > +
> >          init_completion(&ctrl->idle_comp);
> >          init_completion(&ctrl->video_comp);
> >   
> > @@ -1864,6 +1883,18 @@ struct dp_ctrl *dp_ctrl_get(struct device *dev, struct dp_link *link,
> >          return &ctrl->dp_ctrl;
> >   }
> >   
> > -void dp_ctrl_put(struct dp_ctrl *dp_ctrl)
> > +void dp_ctrl_put(struct device *dev, struct dp_ctrl *dp_ctrl)
> >   {
> > +       struct dp_ctrl_private *ctrl;
> > +
> > +       if (!dp_ctrl)
>
> Can this happen?
>
> > +               return;
> > +
> > +       ctrl = container_of(dp_ctrl, struct dp_ctrl_private, dp_ctrl);
> > +
> > +       if (ctrl->opp_table != NULL) {
>
> This is usually written as
>
> 	if (ctrl->opp_table)
>
> > +               dev_pm_opp_of_remove_table(dev);
> > +               dev_pm_opp_put_clkname(ctrl->opp_table);
> > +               ctrl->opp_table = NULL;
> > +       }
> >   }
> > diff --git a/drivers/gpu/drm/msm/dp/dp_ctrl.h b/drivers/gpu/drm/msm/dp/dp_ctrl.h
> > index f60ba93c8678..19b412a93e02 100644
> > --- a/drivers/gpu/drm/msm/dp/dp_ctrl.h
> > +++ b/drivers/gpu/drm/msm/dp/dp_ctrl.h
> > @@ -31,6 +31,6 @@ struct dp_ctrl *dp_ctrl_get(struct device *dev, struct dp_link *link,
> >                          struct dp_panel *panel, struct drm_dp_aux *aux,
> >                          struct dp_power *power, struct dp_catalog *catalog,
> >                          struct dp_parser *parser);
> > -void dp_ctrl_put(struct dp_ctrl *dp_ctrl);
> > +void dp_ctrl_put(struct device *dev, struct dp_ctrl *dp_ctrl);
>
> Is 'dev' not inside 'dp_ctrl'?
>
> >   
> >   #endif /* _DP_CTRL_H_ */
> > diff --git a/drivers/gpu/drm/msm/dp/dp_power.c b/drivers/gpu/drm/msm/dp/dp_power.c
> > index 17c1fc6a2d44..3d75bf09e38f 100644
> > --- a/drivers/gpu/drm/msm/dp/dp_power.c
> > +++ b/drivers/gpu/drm/msm/dp/dp_power.c
> > @@ -8,12 +8,14 @@
> >   #include <linux/clk.h>
> >   #include <linux/clk-provider.h>
> >   #include <linux/regulator/consumer.h>
> > +#include <linux/pm_opp.h>
> >   #include "dp_power.h"
> >   #include "msm_drv.h"
> >   
> >   struct dp_power_private {
> >          struct dp_parser *parser;
> >          struct platform_device *pdev;
> > +       struct device *dev;
> >          struct clk *link_clk_src;
> >          struct clk *pixel_provider;
> >          struct clk *link_provider;
> > @@ -148,18 +150,49 @@ static int dp_power_clk_deinit(struct dp_power_private *power)
> >          return 0;
> >   }
> >   
> > +static int dp_power_clk_set_link_rate(struct dp_power_private *power,
> > +                       struct dss_clk *clk_arry, int num_clk, int enable)
> > +{
> > +       u32 rate;
> > +       int i, rc = 0;
> > +
> > +       for (i = 0; i < num_clk; i++) {
> > +               if (clk_arry[i].clk) {
> > +                       if (clk_arry[i].type == DSS_CLK_PCLK) {
> > +                               if (enable)
> > +                                       rate = clk_arry[i].rate;
> > +                               else
> > +                                       rate = 0;
> > +
> > +                               rc = dev_pm_opp_set_rate(power->dev, rate);
>
> Why do we keep going if rc is non-zero?
>
> > +                       }
> > +
> > +               }
> > +       }
> > +       return rc;
> > +}
> > +
> >   static int dp_power_clk_set_rate(struct dp_power_private *power,
> >                  enum dp_pm_type module, bool enable)
> >   {
> >          int rc = 0;
> >          struct dss_module_power *mp = &power->parser->mp[module];
> >   
> > -       if (enable) {
> > -               rc = msm_dss_clk_set_rate(mp->clk_config, mp->num_clk);
> > +       if (module == DP_CTRL_PM) {
> > +               rc = dp_power_clk_set_link_rate(power, mp->clk_config, mp->num_clk, enable);
> >                  if (rc) {
> > -                       DRM_ERROR("failed to set clks rate.\n");
> > +                       DRM_ERROR("failed to set link clks rate.\n");
> >                          return rc;
> >                  }
> > +       } else {
> > +
> > +               if (enable) {
> > +                       rc = msm_dss_clk_set_rate(mp->clk_config, mp->num_clk);
> > +                       if (rc) {
> > +                               DRM_ERROR("failed to set clks rate.\n");
>
> Not sure we need the period on these error messages.
>
> > +                               return rc;
> > +                       }
> > +               }
> >          }
> >   
> >          rc = msm_dss_enable_clk(mp->clk_config, mp->num_clk, enable);
> >
> > base-commit: 3c0f462da069af12211901ddf26f7e16e6951d9b
> > prerequisite-patch-id: a109eaf08147f50149ad661a58122b6745a52445
>
> Can you rebase this on Rob's msm-next tree
> (https://gitlab.freedesktop.org/drm/msm.git) and test? It doesn't apply
> for me because I have the dp phy patch from there.

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