RE: [PATCH v4 4/5] drm: renesas: rz-du: Move mode_valid logic to per-SoC clock limits

[Biju Das <biju.das.jz@bp.renesas.com>]

Hi,

> -----Original Message-----
> From: Biju Das
> Sent: 20 May 2026 09:16
> Subject: RE: [PATCH v4 4/5] drm: renesas: rz-du: Move mode_valid logic to per-SoC clock limits
> 
> Hi Prabhakar,
> 
> > -----Original Message-----
> > From: Lad, Prabhakar <prabhakar.csengg@gmail.com>
> > Sent: 20 May 2026 09:14
> > Subject: Re: [PATCH v4 4/5] drm: renesas: rz-du: Move mode_valid logic
> > to per-SoC clock limits
> >
> > Hi Biju,
> >
> > Thank you for the review.
> >
> > On Wed, May 20, 2026 at 6:36 AM Biju Das <biju.das.jz@bp.renesas.com> wrote:
> > >
> > > Hi Prabhakar,
> > >
> > > Thanks for the patch.
> > >
> > > > -----Original Message-----
> > > > From: Prabhakar <prabhakar.csengg@gmail.com>
> > > > Sent: 19 May 2026 17:08
> > > > Subject: [PATCH v4 4/5] drm: renesas: rz-du: Move mode_valid logic
> > > > to per-SoC clock limits
> > > >
> > > > From: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
> > > >
> > > > Move pixel clock validation from a fixed encoder check to per SoC
> > > > constraints stored in rzg2l_du_device_info.
> > > >
> > > > Pixel clock limits differ across SoCs in the RZ DU family and
> > > > cannot be expressed by a single shared rule. For example, RZ/G2UL
> > > > and RZ/G2L limit the DPAD0 pixel clock to a narrow window, while
> > > > other SoCs such as RZ/T2H require a
> > wider operating range.
> > > >
> > > > Add mode_clock_min and mode_clock_max fields to
> > > > rzg2l_du_device_info to describe the supported pixel clock range
> > > > for each SoC. Update
> > > > rzg2l_du_encoder_mode_valid() to check these bounds when
> > > > evaluating
> > > > DPAD0 outputs, returning MODE_CLOCK_LOW when the pixel clock falls
> > > > below mode_clock_min and MODE_CLOCK_HIGH when it exceeds mode_clock_max.
> > > >
> > > > Populate the pixel clock limits for both the RZ/G2UL (R9A07G043U)
> > > > and RZ/G2L (R9A07G044) variants to a minimum of 20875 kHz and a
> > > > maximum of
> > > > 83500 kHz.
> > > >
> > > > Signed-off-by: Lad Prabhakar
> > > > <prabhakar.mahadev-lad.rj@bp.renesas.com>
> > > > ---
> > > > v3->v4:
> > > > - Dropped per pad limits
> > > > - Updated commit message to reflect the change in approach.
> > > >
> > > > v2->v3:
> > > > - Moved clock limits from device_info to output_routing to allow
> > > >   per-output constraints.
> > > > - Updated commit message to reflect the change in approach.
> > > >
> > > > v1->v2:
> > > > - Dropped storing info pointer in struct rzg2l_du_encoder as it's not needed.
> > > > ---
> > > >  drivers/gpu/drm/renesas/rz-du/rzg2l_du_drv.c     | 6 +++++-
> > > >  drivers/gpu/drm/renesas/rz-du/rzg2l_du_drv.h     | 4 ++++
> > > >  drivers/gpu/drm/renesas/rz-du/rzg2l_du_encoder.c | 9 ++++++++-
> > > >  3 files changed, 17 insertions(+), 2 deletions(-)
> > > >
> > > > diff --git a/drivers/gpu/drm/renesas/rz-du/rzg2l_du_drv.c
> > > > b/drivers/gpu/drm/renesas/rz- du/rzg2l_du_drv.c index
> > > > 0fef33a5a089..1e4b9f38c55b 100644
> > > > --- a/drivers/gpu/drm/renesas/rz-du/rzg2l_du_drv.c
> > > > +++ b/drivers/gpu/drm/renesas/rz-du/rzg2l_du_drv.c
> > > > @@ -35,6 +35,8 @@ static const struct rzg2l_du_device_info rzg2l_du_r9a07g043u_info = {
> > > >                       .port = 0,
> > > >               },
> > > >       },
> > > > +     .mode_clock_min = 20875,
> > > > +     .mode_clock_max = 83500,
> > > >  };
> > > >
> > > >  static const struct rzg2l_du_device_info rzg2l_du_r9a07g044_info
> > > > = { @@ -48,7 +50,9 @@ static const struct rzg2l_du_device_info rzg2l_du_r9a07g044_info = {
> > > >                       .possible_outputs = BIT(0),
> > > >                       .port = 1,
> > > >               }
> > > > -     }
> > > > +     },
> > > > +     .mode_clock_min = 20875,
> > > > +     .mode_clock_max = 83500,
> > > >  };
> > > >
> > > >  static const struct rzg2l_du_device_info rzg2l_du_r9a09g057_info
> > > > = { diff --git a/drivers/gpu/drm/renesas/rz-du/rzg2l_du_drv.h
> > > > b/drivers/gpu/drm/renesas/rz-du/rzg2l_du_drv.h
> > > > index 58806c2a8f2b..885558eb9547 100644
> > > > --- a/drivers/gpu/drm/renesas/rz-du/rzg2l_du_drv.h
> > > > +++ b/drivers/gpu/drm/renesas/rz-du/rzg2l_du_drv.h
> > > > @@ -44,10 +44,14 @@ struct rzg2l_du_output_routing {
> > > >   * struct rzg2l_du_device_info - DU model-specific information
> > > >   * @channels_mask: bit mask of available DU channels
> > > >   * @routes: array of CRTC to output routes, indexed by output
> > > > (RZG2L_DU_OUTPUT_*)
> > > > + * @mode_clock_min: minimum pixel clock in kHz
> > > > + * @mode_clock_max: maximum pixel clock in kHz
> > > >   */
> > > >  struct rzg2l_du_device_info {
> > > >       unsigned int channels_mask;
> > > >       struct rzg2l_du_output_routing routes[RZG2L_DU_OUTPUT_MAX];
> > > > +     u32 mode_clock_min;
> > > > +     u32 mode_clock_max;
> > > >  };
> > > >
> > > >  #define RZG2L_DU_MAX_CRTCS           1
> > > > diff --git a/drivers/gpu/drm/renesas/rz-du/rzg2l_du_encoder.c
> > > > b/drivers/gpu/drm/renesas/rz- du/rzg2l_du_encoder.c index
> > > > 0e567b57a408..56220139a149 100644
> > > > --- a/drivers/gpu/drm/renesas/rz-du/rzg2l_du_encoder.c
> > > > +++ b/drivers/gpu/drm/renesas/rz-du/rzg2l_du_encoder.c
> > > > @@ -50,8 +50,15 @@ rzg2l_du_encoder_mode_valid(struct drm_encoder *encoder,
> > > >                           const struct drm_display_mode *mode)  {
> > > >       struct rzg2l_du_encoder *renc = to_rzg2l_encoder(encoder);
> > > > +     struct rzg2l_du_device *rcdu = to_rzg2l_du_device(renc->base.dev);
> > > > +     const struct rzg2l_du_device_info *info = rcdu->info;
> > > >
> > > > -     if (renc->output == RZG2L_DU_OUTPUT_DPAD0 && mode->clock > 83500)
> > > > +     if (renc->output != RZG2L_DU_OUTPUT_DPAD0)
> > > > +             return MODE_OK;
> > > > +
> > > > +     if (info->mode_clock_min && mode->clock <
> > > > + info->mode_clock_min)
> > >
> > > I will avoid checking the first part as it is mandatory for SoCs
> > > with DPI support and DPI check above make sure that this part of the
> > > code is reachable only for DPI output.
> > >
> > Will you fix up while applying or shall I send a new version?
> 
> I can take care of this if there are no other comments.

Reviewed-by: Biju Das <biju.das.jz@bp.renesas.com>

Cheers,
Biju

> 
> Cheers,
> Biju
> 
> >
> > Cheers,
> > Prabhakar
> > > > +             return MODE_CLOCK_LOW;
> > > > +     if (info->mode_clock_max && mode->clock >
> > > > + info->mode_clock_max)
> > >
> > > Same here.
> > >
> > > Cheers,
> > > Biju
> > >
> > > >               return MODE_CLOCK_HIGH;
> > > >
> > > >       return MODE_OK;
> > > > --
> > > > 2.54.0
> > >