[PATCH v2 0/4] Add DU support for RZ/T2H and RZ/N2H SoCs

[PATCH v2 0/4] Add DU support for RZ/T2H and RZ/N2H SoCs

[Prabhakar]

From: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>

Hi All,

This series adds support for the Display Unit (DU) on the RZ/T2H
and RZ/N2H (R9A09G087) SoCs. The DU on these platforms is
functionally similar to the RZ/G2UL DU but includes some SoC
specific differences such as a single output port and explicit
DPI output enable control. The series includes the following
changes:
1. Add device tree bindings for the RZ/T2H and RZ/N2H DU variants,
   including a new compatible string.
2. Make the DU reset control optional to allow probing on RZ/T2H
   where the DU does not have a reset line.
3. Move pixel clock validation logic to per-SoC constraints in
   rzg2l_du_device_info to accommodate different clock limits
   across SoCs.
4. Implement support for the RZ/T2H DU variant in the driver,
   including handling of the DPI output enable signal.

Patches are rebased on next-20260507 and apply on drm-next.

v1->v2:
- Dropped the "port" property in favor of "ports" with a single port@0
  child, to align with the existing RZ/G2L bindings and simplify the
  device tree structure.
- Updated the commit message to reflect the change from "port" to "ports".
- Dropped storing info pointer in struct rzg2l_du_encoder as it's not
  needed.
- Add Reviewed-by tags from Laurent for patches 2-4.
- Rebase on latest next-20260507.

Cheers,
Prabhakar

Lad Prabhakar (4):
  dt-bindings: display: renesas,rzg2l-du: Add RZ/T2H and RZ/N2H support
  drm: renesas: rz-du: Make DU reset control optional for RZ/T2H support
  drm: renesas: rz-du: Move mode_valid logic to per-SoC clock limits
  drm: renesas: rz-du: Add support for RZ/T2H SoC

 .../bindings/display/renesas,rzg2l-du.yaml    | 20 +++++++++++++++++--
 drivers/gpu/drm/renesas/rz-du/rzg2l_du_crtc.c |  9 +++++++--
 drivers/gpu/drm/renesas/rz-du/rzg2l_du_drv.c  | 16 +++++++++++++++
 drivers/gpu/drm/renesas/rz-du/rzg2l_du_drv.h  | 14 +++++++++++++
 .../gpu/drm/renesas/rz-du/rzg2l_du_encoder.c  |  6 +++++-
 5 files changed, 60 insertions(+), 5 deletions(-)

-- 
2.54.0

[PATCH v2 1/4] dt-bindings: display: renesas,rzg2l-du: Add RZ/T2H and RZ/N2H support

[Prabhakar]

From: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>

Document the Display Unit (DU) support for the RZ/T2H and RZ/N2H SoCs.

The DU block on RZ/T2H is functionally equivalent to the RZ/G2UL DU and
supports the DPI interface, but includes SoC-specific register differences
and has no reset control. Add a dedicated compatible string to represent
this variant and update the allOf constraints accordingly.

As the DU implementation on RZ/N2H matches RZ/T2H, describe it using an
RZ/N2H specific compatible string with the RZ/T2H compatible as fallback.

Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
---
v1->v2:
- Dropped the "port" property in favor of "ports" with a single port@0
  child, to align with the existing RZ/G2L bindings and simplify the
  device tree structure.
- Updated the commit message to reflect the change from "port" to "ports".
- Dropped RB tag from Rob due to above changes.
---
 .../bindings/display/renesas,rzg2l-du.yaml    | 20 +++++++++++++++++--
 1 file changed, 18 insertions(+), 2 deletions(-)

diff --git a/Documentation/devicetree/bindings/display/renesas,rzg2l-du.yaml b/Documentation/devicetree/bindings/display/renesas,rzg2l-du.yaml
index 2cc66dcef870..18776ac9e7c7 100644
--- a/Documentation/devicetree/bindings/display/renesas,rzg2l-du.yaml
+++ b/Documentation/devicetree/bindings/display/renesas,rzg2l-du.yaml
@@ -21,6 +21,7 @@ properties:
           - renesas,r9a07g043u-du # RZ/G2UL
           - renesas,r9a07g044-du # RZ/G2{L,LC}
           - renesas,r9a09g057-du # RZ/V2H(P)
+          - renesas,r9a09g077-du # RZ/T2H
       - items:
           - enum:
               - renesas,r9a07g054-du    # RZ/V2L
@@ -28,6 +29,9 @@ properties:
       - items:
           - const: renesas,r9a09g056-du # RZ/V2N
           - const: renesas,r9a09g057-du # RZ/V2H(P) fallback
+      - items:
+          - const: renesas,r9a09g087-du # RZ/N2H
+          - const: renesas,r9a09g077-du # RZ/T2H fallback
 
   reg:
     maxItems: 1
@@ -83,7 +87,6 @@ required:
   - interrupts
   - clocks
   - clock-names
-  - resets
   - power-domains
   - ports
   - renesas,vsps
@@ -95,7 +98,9 @@ allOf:
       properties:
         compatible:
           contains:
-            const: renesas,r9a07g043u-du
+            enum:
+              - renesas,r9a07g043u-du
+              - renesas,r9a09g077-du
     then:
       properties:
         ports:
@@ -137,6 +142,17 @@ allOf:
 
           required:
             - port@0
+  - if:
+      properties:
+        compatible:
+          contains:
+            const: renesas,r9a09g077-du
+    then:
+      properties:
+        resets: false
+    else:
+      required:
+        - resets
 
 examples:
   # RZ/G2L DU
-- 
2.54.0

[PATCH v2 2/4] drm: renesas: rz-du: Make DU reset control optional for RZ/T2H support

[Prabhakar]

From: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>

Update the DU CRTC initialisation to request the reset control using
devm_reset_control_get_optional_shared(). On RZ/T2H SoCs the DU block does
not expose a reset line, and treating the reset as mandatory prevents the
driver from probing on those platforms.

Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
---
v1->v2:
- Added Reviewed-by tag from Laurent Pinchart.
---
 drivers/gpu/drm/renesas/rz-du/rzg2l_du_crtc.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/renesas/rz-du/rzg2l_du_crtc.c b/drivers/gpu/drm/renesas/rz-du/rzg2l_du_crtc.c
index 26b95153ce88..48065f4952a3 100644
--- a/drivers/gpu/drm/renesas/rz-du/rzg2l_du_crtc.c
+++ b/drivers/gpu/drm/renesas/rz-du/rzg2l_du_crtc.c
@@ -380,7 +380,7 @@ int rzg2l_du_crtc_create(struct rzg2l_du_device *rcdu)
 	struct drm_plane *primary;
 	int ret;
 
-	rcrtc->rstc = devm_reset_control_get_shared(rcdu->dev, NULL);
+	rcrtc->rstc = devm_reset_control_get_optional_shared(rcdu->dev, NULL);
 	if (IS_ERR(rcrtc->rstc)) {
 		dev_err(rcdu->dev, "can't get cpg reset\n");
 		return PTR_ERR(rcrtc->rstc);
-- 
2.54.0

[PATCH v2 3/4] drm: renesas: rz-du: Move mode_valid logic to per-SoC clock limits

[Prabhakar]

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 (R9A07G043U)
limits the DPAD0 pixel clock to 83.5 MHz, 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 return MODE_CLOCK_LOW when the pixel
clock falls below mode_clock_min and MODE_CLOCK_HIGH when it exceeds
mode_clock_max.

Set the pixel clock limits for RZ/G2UL(R9A07G043U) to 20.875MHz minimum
and 83.5MHz maximum.

Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
---
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     | 2 ++
 drivers/gpu/drm/renesas/rz-du/rzg2l_du_drv.h     | 4 ++++
 drivers/gpu/drm/renesas/rz-du/rzg2l_du_encoder.c | 6 +++++-
 3 files changed, 11 insertions(+), 1 deletion(-)

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..3b7162c6e1f4 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 = {
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..5c672549bc84 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 +50,12 @@ 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 (info->mode_clock_min && mode->clock < info->mode_clock_min)
+		return MODE_CLOCK_LOW;
+	if (info->mode_clock_max && mode->clock > info->mode_clock_max)
 		return MODE_CLOCK_HIGH;
 
 	return MODE_OK;
-- 
2.54.0

[PATCH v2 4/4] drm: renesas: rz-du: Add support for RZ/T2H SoC

[Prabhakar]

From: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>

The RZ/T2H (R9A09G077) SoC includes a DU with a DPI interface,
supporting resolutions up to WXGA with two RPFs for layer blending.
Unlike earlier RZ/G2L SoCs, RZ/T2H requires explicit assertion of a
DPI output-enable signal (DU_MCR0_DPI_EN) during CRTC startup.

Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
---
v1->v2:
- Added Reviewed-by tag from Laurent Pinchart.
---
 drivers/gpu/drm/renesas/rz-du/rzg2l_du_crtc.c |  7 ++++++-
 drivers/gpu/drm/renesas/rz-du/rzg2l_du_drv.c  | 14 ++++++++++++++
 drivers/gpu/drm/renesas/rz-du/rzg2l_du_drv.h  | 10 ++++++++++
 3 files changed, 30 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/renesas/rz-du/rzg2l_du_crtc.c b/drivers/gpu/drm/renesas/rz-du/rzg2l_du_crtc.c
index 48065f4952a3..d0f01aa642a7 100644
--- a/drivers/gpu/drm/renesas/rz-du/rzg2l_du_crtc.c
+++ b/drivers/gpu/drm/renesas/rz-du/rzg2l_du_crtc.c
@@ -28,6 +28,7 @@
 #include "rzg2l_du_vsp.h"
 
 #define DU_MCR0			0x00
+#define DU_MCR0_DPI_EN		BIT(0)
 #define DU_MCR0_DI_EN		BIT(8)
 
 #define DU_DITR0		0x10
@@ -217,8 +218,12 @@ static void rzg2l_du_crtc_put(struct rzg2l_du_crtc *rcrtc)
 static void rzg2l_du_start_stop(struct rzg2l_du_crtc *rcrtc, bool start)
 {
 	struct rzg2l_du_device *rcdu = rcrtc->dev;
+	u32 val = DU_MCR0_DI_EN;
 
-	writel(start ? DU_MCR0_DI_EN : 0, rcdu->mmio + DU_MCR0);
+	if (start && rzg2l_du_has(rcdu, RZG2L_DU_FEATURE_DPIO_OE))
+		val |= DU_MCR0_DPI_EN;
+
+	writel(start ? val : 0, rcdu->mmio + DU_MCR0);
 }
 
 static void rzg2l_du_crtc_start(struct rzg2l_du_crtc *rcrtc)
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 3b7162c6e1f4..fc55dfffebaf 100644
--- a/drivers/gpu/drm/renesas/rz-du/rzg2l_du_drv.c
+++ b/drivers/gpu/drm/renesas/rz-du/rzg2l_du_drv.c
@@ -63,10 +63,24 @@ static const struct rzg2l_du_device_info rzg2l_du_r9a09g057_info = {
 	},
 };
 
+static const struct rzg2l_du_device_info rzg2l_du_r9a09g077_info = {
+	.channels_mask = BIT(0),
+	.routes = {
+		[RZG2L_DU_OUTPUT_DPAD0] = {
+			.possible_outputs = BIT(0),
+			.port = 0,
+		},
+	},
+	.features = RZG2L_DU_FEATURE_DPIO_OE,
+	.mode_clock_min = 5000,
+	.mode_clock_max = 100000,
+};
+
 static const struct of_device_id rzg2l_du_of_table[] = {
 	{ .compatible = "renesas,r9a07g043u-du", .data = &rzg2l_du_r9a07g043u_info },
 	{ .compatible = "renesas,r9a07g044-du", .data = &rzg2l_du_r9a07g044_info },
 	{ .compatible = "renesas,r9a09g057-du", .data = &rzg2l_du_r9a09g057_info },
+	{ .compatible = "renesas,r9a09g077-du", .data = &rzg2l_du_r9a09g077_info },
 	{ /* sentinel */ }
 };
 
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 885558eb9547..baf076d69cda 100644
--- a/drivers/gpu/drm/renesas/rz-du/rzg2l_du_drv.h
+++ b/drivers/gpu/drm/renesas/rz-du/rzg2l_du_drv.h
@@ -20,6 +20,8 @@
 struct device;
 struct drm_property;
 
+#define RZG2L_DU_FEATURE_DPIO_OE	BIT(0)	/* Has DPIO output enable control */
+
 enum rzg2l_du_output {
 	RZG2L_DU_OUTPUT_DSI0,
 	RZG2L_DU_OUTPUT_DPAD0,
@@ -46,12 +48,14 @@ struct rzg2l_du_output_routing {
  * @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
+ * @features: device features (RZG2L_DU_FEATURE_*)
  */
 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;
+	unsigned int features;
 };
 
 #define RZG2L_DU_MAX_CRTCS		1
@@ -77,6 +81,12 @@ static inline struct rzg2l_du_device *to_rzg2l_du_device(struct drm_device *dev)
 	return container_of(dev, struct rzg2l_du_device, ddev);
 }
 
+static inline bool rzg2l_du_has(struct rzg2l_du_device *rcdu,
+				unsigned int feature)
+{
+	return rcdu->info->features & feature;
+}
+
 const char *rzg2l_du_output_name(enum rzg2l_du_output output);
 
 #endif /* __RZG2L_DU_DRV_H__ */
-- 
2.54.0

Re: [PATCH v2 1/4] dt-bindings: display: renesas,rzg2l-du: Add RZ/T2H and RZ/N2H support

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Low] The conditional constraints for renesas,r9a09g077-du fail to explicitly disallow port@1, permitting invalid device trees to silently pass validation.
--

commit cd9bf5724c5d57e0dd67fd27e0187153179b0578
Author: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>

dt-bindings: display: renesas,rzg2l-du: Add RZ/T2H and RZ/N2H support

This commit documents the Display Unit (DU) support for the RZ/T2H and RZ/N2H
SoCs. It adds new compatible strings and updates the allOf constraints to
handle the SoCs' specific register differences and lack of reset control.

> diff --git a/Documentation/devicetree/bindings/display/renesas,rzg2l-du.yaml b/Documentation/devicetree/bindings/display/renesas,rzg2l-du.yaml
> index 2cc66dcef870a..18776ac9e7c7e 100644
> --- a/Documentation/devicetree/bindings/display/renesas,rzg2l-du.yaml
> +++ b/Documentation/devicetree/bindings/display/renesas,rzg2l-du.yaml
[ ... ]
> @@ -95,7 +98,9 @@ allOf:
>        properties:
>          compatible:
>            contains:
> -            const: renesas,r9a07g043u-du
> +            enum:
> +              - renesas,r9a07g043u-du
> +              - renesas,r9a09g077-du
>      then:
>        properties:
>          ports:
> @@ -137,6 +142,17 @@ allOf:
>  
>            required:
>              - port@0

Should we also explicitly set port@1 to false here?

The base schema for 'ports' allows both 'port@0' and 'port@1' via the
patternProperty '^port@[0-1]$'. By not explicitly disallowing port@1 in this
conditional block for the single-port RZ/T2H DU variant, would a malformed
device tree containing an extra port@1 incorrectly pass schema validation?

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260508111744.771659-1-prabhakar.mahadev-lad.rj@bp.renesas.com?part=1

Re: [PATCH v2 3/4] drm: renesas: rz-du: Move mode_valid logic to per-SoC clock limits

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [High] Moving the pixel clock limits from an output-specific check to a global per-SoC limit drops the DPAD0 clock limit for RZ/G2L and prevents setting per-interface limits.
--

commit df71add63cd01bd86e697f0d293fcfc2d68de83e
Author: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>

drm: renesas: rz-du: Move mode_valid logic to per-SoC clock limits

This commit shifts pixel clock validation from a hardcoded encoder output
check to per-SoC limits defined in rzg2l_du_device_info. It adds clock
bounds for RZ/G2UL and checks these limits against the display mode clock.

> 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 5e6dd16705e60..2fb79d11ab151 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 +50,12 @@ 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 (info->mode_clock_min && mode->clock < info->mode_clock_min)
> +		return MODE_CLOCK_LOW;
> +	if (info->mode_clock_max && mode->clock > info->mode_clock_max)
>  		return MODE_CLOCK_HIGH;

Does replacing the output-specific check with a global per-SoC limit
unintentionally drop the 83.5 MHz restriction for DPAD0 on SoCs with
multiple outputs?

Looking at rzg2l_du_r9a07g044_info in rzg2l_du_drv.c, the RZ/G2L SoC
supports both DSI0 and DPAD0 outputs, but no mode_clock_max is set for it
by this patch. This means DPAD0 on RZ/G2L loses its original 83.5 MHz
limit.

If a global mode_clock_max were added to the RZ/G2L info struct to restore
this limit, wouldn't it incorrectly throttle the DSI0 interface as well?

Should these limits be placed in struct rzg2l_du_output_routing instead
so that per-interface limits can still be enforced?

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260508111744.771659-1-prabhakar.mahadev-lad.rj@bp.renesas.com?part=3