Re: [PATCH v2 1/2] drm/msm/dp: Add support for SC7280 eDP

[sbillaka]

Hi Stephen,

On 2021-10-21 23:32, Stephen Boyd wrote:
> Quoting Sankeerth Billakanti (2021-10-20 05:14:10)
> > diff --git a/drivers/gpu/drm/msm/dp/dp_ctrl.c 
> > b/drivers/gpu/drm/msm/dp/dp_ctrl.c
> > index 62e75dc..9fea49c 100644
> > --- a/drivers/gpu/drm/msm/dp/dp_ctrl.c
> > +++ b/drivers/gpu/drm/msm/dp/dp_ctrl.c
> > @@ -1238,9 +1240,21 @@ static int dp_ctrl_link_train(struct 
> > dp_ctrl_private *ctrl,
> >         link_info.capabilities = DP_LINK_CAP_ENHANCED_FRAMING;
> >
> >         dp_aux_link_configure(ctrl->aux, &link_info);
> > +
> > +       if (dpcd[DP_MAX_DOWNSPREAD] & DP_MAX_DOWNSPREAD_0_5) {
>
> Please add a static inline macro in include/drm/drm_dp_helper.h that
> makes this more readable. Something similar to drm_dp_is_branch() but
> with a human readable replacement for "is_branch". Maybe drm_dp_ssc()?
Okay, I will add a macro, drm_dp_max_downspread (to be consistent with 
the spec and other macros in the file) in drm_dp_helper.h file.

> > +               ssc = DP_SPREAD_AMP_0_5;
> > +               drm_dp_dpcd_write(ctrl->aux, DP_DOWNSPREAD_CTRL, &ssc, 
> > 1);
> > +       }
> > +
> >         drm_dp_dpcd_write(ctrl->aux, DP_MAIN_LINK_CHANNEL_CODING_SET,
> >                                 &encoding, 1);
> >
> > +       if (dpcd[DP_EDP_CONFIGURATION_CAP] & 
> > DP_ALTERNATE_SCRAMBLER_RESET_CAP) {
>
> And this one already has a helper,
> drm_dp_alternate_scrambler_reset_cap().
Okay, I will use that.

> > +               assr = DP_ALTERNATE_SCRAMBLER_RESET_ENABLE;
> > +               drm_dp_dpcd_write(ctrl->aux, DP_EDP_CONFIGURATION_SET,
> > +                               &assr, 1);
> > +       }
> > +
> >         ret = dp_ctrl_link_train_1(ctrl, training_step);
> >         if (ret) {
> >                 DRM_ERROR("link training #1 failed. ret=%d\n", ret);
> > @@ -1312,9 +1326,11 @@ static int 
> > dp_ctrl_enable_mainlink_clocks(struct dp_ctrl_private *ctrl)
> >         struct dp_io *dp_io = &ctrl->parser->io;
> >         struct phy *phy = dp_io->phy;
> >         struct phy_configure_opts_dp *opts_dp = &dp_io->phy_opts.dp;
> > +       const u8 *dpcd = ctrl->panel->dpcd;
> >
> >         opts_dp->lanes = ctrl->link->link_params.num_lanes;
> >         opts_dp->link_rate = ctrl->link->link_params.rate / 100;
> > +       opts_dp->ssc = dpcd[DP_MAX_DOWNSPREAD] & 
> > DP_MAX_DOWNSPREAD_0_5;
> >         dp_ctrl_set_clock_rate(ctrl, DP_CTRL_PM, "ctrl_link",
> >                                         ctrl->link->link_params.rate * 
> > 1000);
> >
> > @@ -1406,7 +1422,7 @@ void dp_ctrl_host_deinit(struct dp_ctrl 
> > *dp_ctrl)
> >
> >  static bool dp_ctrl_use_fixed_nvid(struct dp_ctrl_private *ctrl)
> >  {
> > -       u8 *dpcd = ctrl->panel->dpcd;
> > +       const u8 *dpcd = ctrl->panel->dpcd;
> >
> >         /*
> >          * For better interop experience, used a fixed NVID=0x8000
> > diff --git a/drivers/gpu/drm/msm/dp/dp_display.c 
> > b/drivers/gpu/drm/msm/dp/dp_display.c
> > index c867745..c16311b 100644
> > --- a/drivers/gpu/drm/msm/dp/dp_display.c
> > +++ b/drivers/gpu/drm/msm/dp/dp_display.c
> > @@ -144,8 +144,16 @@ static const struct msm_dp_config sc8180x_dp_cfg 
> > = {
> >         .num_descs = 3,
> >  };
> >
> > +static const struct msm_dp_config sc7280_dp_cfg = {
> > +       .descs = (struct msm_dp_desc[]) {
>
> const
Will add it.

> > +               { .io_start = 0x0aea0000, .connector_type = 
> > DRM_MODE_CONNECTOR_eDP },
> > +       },
> > +       .num_descs = 1,
> > +};
> > +
> >  static const struct of_device_id dp_dt_match[] = {
> >         { .compatible = "qcom,sc7180-dp", .data = &sc7180_dp_cfg },
> > +       { .compatible = "qcom,sc7280-edp", .data = &sc7280_dp_cfg },
> >         { .compatible = "qcom,sc8180x-dp", .data = &sc8180x_dp_cfg },
> >         { .compatible = "qcom,sc8180x-edp", .data = &sc8180x_dp_cfg },
> >         {}
> > @@ -1440,7 +1448,7 @@ void msm_dp_irq_postinstall(struct msm_dp 
> > *dp_display)
> >
> >         dp_hpd_event_setup(dp);
> >
> > -       dp_add_event(dp, EV_HPD_INIT_SETUP, 0, 100);
> > +       dp_add_event(dp, EV_HPD_INIT_SETUP, 0, 1);
>
> This has no explanation. What is it?
Will add explanation for it as a comment.