[PATCH v4 0/2] Add support for Renesas RZ/G3L LVDS encoder

[PATCH v4 0/2] Add support for Renesas RZ/G3L LVDS encoder

[Biju]

From: Biju Das <biju.das.jz@bp.renesas.com>

Add support for the RZ/G3L LVDS encoder driver. It operates in single-link
mode with 4 lanes (Data) + 1 lane (Clock) and supports pixel clock rates
from 25 to 87 MHz. The LVDS module cannot be used at the same time as
MIPI-DSI. However, LVDS and the DSI interface share a peripheral clock and
the MIPI_DSI_PRESET_N reset signal. Also, the MIPI_DSI_CMN_RSTB and
MIPI_DSI_ARESET_N reset signals must be asserted before using the LVDS
module.

This patch series depend upon [1]

[1]
 https://lore.kernel.org/all/20260608-drm-no-more-bridge-reset-v2-0-0a91018bf886@kernel.org/

v3->v4:
 * Reworked bindings, dropping parent node containing simple-mfd and
   syson.
 * Dropped the tags
 * Dropped the header files clk.h and syscon.h
 * Dropped next_bridge check in attach().
 * Dropped syscon for getting regmap.
 * Replaced the below macros to match the hardware manual:
	LVDS_0_CTL_FMT_SEL_MSK->LVDS_0_CTL_FMT_SEL0_MSK
	LVDS_0_PHY_CH_IO_EN_MSK->LVDS_0_PHY_CH_IO_EN0_MSK
	Replaced LVDS_0_PHY_CH_IO_EN->LVDS_0_PHY_CH_IO_EN0
 * Replaced atomic_reset()->atomic_create_state().
v2->v3:
 * Collected tags.
v2->v2[1]:
 * Dropped patch#1 as it is accepted.
 * Replace drm_atomic_state with drm_atomic_commit in
   rzg3l_lvds_atomic_{en,dis}able().
 * Drop local variable ret and dev_err() messages in
   rzg3l_lvds_atomic_enable(); use WARN_ON() instead to
   capture unexpected failures since atomic_enable should not fail.
 * Drop local variable next_bridge from rzg3l_lvds_probe().
[1] https://lore.kernel.org/all/20260524194457.479681-1-biju.das.jz@bp.renesas.com/
v1->v2:
 * Collected the tags for binding patches.
 * Dropped unused function rzg3l_lvds_is_connected() and removed the 
   corresponding header file rzg3l_lvds.h
 * Dropped next_bridge from struct rzg3l_lvds instead using bridge's
   next_bridge.
 * Replaced pm_runtime_resume_and_get()->pm_runtime_get_sync() as
   atomic_enable doesn't fail and for each enable there always will be an
   atomic_disable() call.
 * Started using DEFINE_RUNTIME_DEV_PM_OPS for PM callback.
 * Replaced rzg3l_lvds_parse_dt() with devm_drm_of_get_bridge() in probe()
 * Started using reset_control_bulk_*() in rzg3l_lvds_pm_runtime_{suspend,
   resume}().

Biju Das (2):
  dt-bindings: display: bridge: Document Renesas RZ/G3L LVDS encoder
  drm: renesas: rz-du: Add support for RZ/G3L LVDS encoder

 .../bridge/renesas,r9a08g046-lvds.yaml        | 120 ++++++++
 drivers/gpu/drm/renesas/rz-du/Kconfig         |  13 +
 drivers/gpu/drm/renesas/rz-du/Makefile        |   1 +
 drivers/gpu/drm/renesas/rz-du/rzg3l_lvds.c    | 285 ++++++++++++++++++
 .../gpu/drm/renesas/rz-du/rzg3l_lvds_regs.h   |  26 ++
 5 files changed, 445 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/display/bridge/renesas,r9a08g046-lvds.yaml
 create mode 100644 drivers/gpu/drm/renesas/rz-du/rzg3l_lvds.c
 create mode 100644 drivers/gpu/drm/renesas/rz-du/rzg3l_lvds_regs.h

-- 
2.43.0

[PATCH v4 1/2] dt-bindings: display: bridge: Document Renesas RZ/G3L LVDS encoder

[Biju]

From: Biju Das <biju.das.jz@bp.renesas.com>

Document the LVDS encoder IP found on the RZ/G3L SoC. It supports
single-link mode. LVDS and the DSI interface share a peripheral clock and
the MIPI_DSI_PRESET_N reset signal. However, the LVDS module cannot be
used at the same time as MIPI-DSI.

Signed-off-by: Tommaso Merciai <tommaso.merciai.xr@bp.renesas.com>
Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
---
v3->v4:
 * Dropped the tags as it is a rework dropping parent node that contains
   simple-mfd and syscon.
v2->v3:
 * Collected tag.
v2->v2[1]:
 * No change.
[1] https://lore.kernel.org/all/20260524195829.960401F000E9@smtp.kernel.org/
v1->v2:
 * Collected tag.
---
 .../bridge/renesas,r9a08g046-lvds.yaml        | 120 ++++++++++++++++++
 1 file changed, 120 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/display/bridge/renesas,r9a08g046-lvds.yaml

diff --git a/Documentation/devicetree/bindings/display/bridge/renesas,r9a08g046-lvds.yaml b/Documentation/devicetree/bindings/display/bridge/renesas,r9a08g046-lvds.yaml
new file mode 100644
index 000000000000..4cd7b688fbf7
--- /dev/null
+++ b/Documentation/devicetree/bindings/display/bridge/renesas,r9a08g046-lvds.yaml
@@ -0,0 +1,120 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/display/bridge/renesas,r9a08g046-lvds.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Renesas RZ/G3L LVDS Encoder
+
+maintainers:
+  - Biju Das <biju.das.jz@bp.renesas.com>
+  - Tommaso Merciai <tommaso.merciai.xr@bp.renesas.com>
+
+description: |
+  This binding describes the LVDS encoder embedded in the Renesas RZ/G3L
+  SoC. The encoder can operate in LVDS Single-link mode with 4 lanes
+  (Data) + 1 lane (Clock).
+
+properties:
+  compatible:
+    const: renesas,r9a08g046-lvds
+
+  reg:
+    maxItems: 1
+
+  clocks:
+    items:
+      - description: Peripheral clock
+      - description: PHY clock
+      - description: Dot clock
+
+  clock-names:
+    items:
+      - const: pclk
+      - const: phyclk
+      - const: dotclk
+
+  resets:
+    items:
+      - description: LVDS_RESET_N
+      - description: MIPI_DSI_PRESET_N
+      - description: MIPI_DSI_CMN_RSTB
+      - description: MIPI_DSI_ARESET_N
+
+  reset-names:
+    items:
+      - const: lvdrst
+      - const: prst
+      - const: rst
+      - const: arst
+
+  power-domains:
+    maxItems: 1
+
+  ports:
+    $ref: /schemas/graph.yaml#/properties/ports
+
+    properties:
+      port@0:
+        $ref: /schemas/graph.yaml#/properties/port
+        description: Input channel, directly connected to the Display Unit.
+
+      port@1:
+        $ref: /schemas/graph.yaml#/properties/port
+        description: |
+          Output channel, directly connected to the LVDS panel or bridge.
+
+    required:
+      - port@0
+      - port@1
+
+required:
+  - compatible
+  - reg
+  - clocks
+  - clock-names
+  - resets
+  - reset-names
+  - power-domains
+  - ports
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/clock/renesas,r9a08g046-cpg.h>
+
+    lvds@108a0000 {
+        compatible = "renesas,r9a08g046-lvds";
+        reg = <0x108a0000 0x10000>;
+        clocks = <&cpg CPG_MOD R9A08G046_MIPI_DSI_PCLK>,
+                 <&cpg CPG_MOD R9A08G046_LVDS_PLLCLK>,
+                 <&cpg CPG_MOD R9A08G046_LVDS_CLK_DOT0>;
+        clock-names = "pclk", "phyclk", "dotclk";
+        resets = <&cpg R9A08G046_LVDS_RESET_N>,
+                 <&cpg R9A08G046_MIPI_DSI_PRESET_N>,
+                 <&cpg R9A08G046_MIPI_DSI_CMN_RSTB>,
+                 <&cpg R9A08G046_MIPI_DSI_ARESET_N>;
+        reset-names = "lvdrst", "prst", "rst", "arst";
+        power-domains = <&cpg>;
+
+        ports {
+            #address-cells = <1>;
+            #size-cells = <0>;
+
+            port@0 {
+                reg = <0>;
+                lvds0_in: endpoint {
+                    remote-endpoint = <&du_out_lvds0>;
+                };
+            };
+
+            port@1 {
+                reg = <1>;
+                lvds0_out: endpoint {
+                    remote-endpoint = <&panel_in>;
+                };
+            };
+        };
+    };
+...
-- 
2.43.0

[PATCH v4 2/2] drm: renesas: rz-du: Add support for RZ/G3L LVDS encoder

[Biju]

From: Biju Das <biju.das.jz@bp.renesas.com>

Add support for the RZ/G3L LVDS encoder driver. It operates in single-link
mode with 4 lanes (Data) + 1 lane (Clock) and supports pixel clock rates
from 25 to 87 MHz. The LVDS module cannot be used at the same time as
MIPI-DSI. However, LVDS and the DSI interface share a peripheral clock and
the MIPI_DSI_PRESET_N reset signal. Also, the MIPI_DSI_CMN_RSTB and
MIPI_DSI_ARESET_N reset signals must be asserted before using the LVDS
module.

Signed-off-by: Tommaso Merciai <tommaso.merciai.xr@bp.renesas.com>
Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
---
v3->v4:
 * Dropped the header files clk.h and syscon.h
 * Dropped next_bridge check in attach().
 * Dropped syscon for getting regmap.
 * Replaced the below macros to match with hardware manual:
	LVDS_0_CTL_FMT_SEL_MSK->LVDS_0_CTL_FMT_SEL0_MSK
	LVDS_0_PHY_CH_IO_EN_MSK->LVDS_0_PHY_CH_IO_EN0_MSK
	Replaced LVDS_0_PHY_CH_IO_EN->LVDS_0_PHY_CH_IO_EN0
 * Replaced atomic_reset()->atomic_create_state()
 * Dropped the tags as there are new changes.
v2->v3:
 * Collected tags.
v2->v2[1]:
 * Replace drm_atomic_state with drm_atomic_commit in
   rzg3l_lvds_atomic_{en,dis}able().
 * Drop local variable ret and dev_err() messages in
   rzg3l_lvds_atomic_enable(); use WARN_ON() instead to
   capture unexpected failures since atomic_enable should not fail.
 * Drop local variable next_bridge from rzg3l_lvds_probe().
[1] https://lore.kernel.org/all/20260524194457.479681-3-biju.das.jz@bp.renesas.com/
v1->v2:
 * Dropped unused function rzg3l_lvds_is_connected() and removed the 
   corresponding header file rzg3l_lvds.h
 * Dropped next_bridge from struct rzg3l_lvds instead using bridge's
   next_bridge.
 * Replaced pm_runtime_resume_and_get()->pm_runtime_get_sync() as
   atomic_enable doesn't fail and for each enable there always will be an
   atomic_disable() call.
 * Started using DEFINE_RUNTIME_DEV_PM_OPS for PM callback.
 * Replaced rzg3l_lvds_parse_dt() with devm_drm_of_get_bridge() in probe()
 * Started using reset_control_bulk_*() in rzg3l_lvds_pm_runtime_{suspend,
   resume}()
---
 drivers/gpu/drm/renesas/rz-du/Kconfig         |  13 +
 drivers/gpu/drm/renesas/rz-du/Makefile        |   1 +
 drivers/gpu/drm/renesas/rz-du/rzg3l_lvds.c    | 285 ++++++++++++++++++
 .../gpu/drm/renesas/rz-du/rzg3l_lvds_regs.h   |  26 ++
 4 files changed, 325 insertions(+)
 create mode 100644 drivers/gpu/drm/renesas/rz-du/rzg3l_lvds.c
 create mode 100644 drivers/gpu/drm/renesas/rz-du/rzg3l_lvds_regs.h

diff --git a/drivers/gpu/drm/renesas/rz-du/Kconfig b/drivers/gpu/drm/renesas/rz-du/Kconfig
index 7f2ef7137ae5..1e5b3dd1c0de 100644
--- a/drivers/gpu/drm/renesas/rz-du/Kconfig
+++ b/drivers/gpu/drm/renesas/rz-du/Kconfig
@@ -26,3 +26,16 @@ config DRM_RZG2L_MIPI_DSI
 	def_tristate DRM_RZG2L_DU
 	depends on DRM_RZG2L_USE_MIPI_DSI
 	select DRM_MIPI_DSI
+
+config DRM_RZG3L_USE_LVDS
+	bool "RZ/G3L DU LVDS Encoder Support"
+	depends on DRM_BRIDGE && OF
+	default DRM_RZG2L_DU
+	help
+	  Enable support for the RZ/G3L Display Unit embedded LVDS encoder.
+
+config DRM_RZG3L_LVDS
+	def_tristate DRM_RZG2L_DU
+	depends on DRM_RZG3L_USE_LVDS
+	select DRM_KMS_HELPER
+	select DRM_PANEL
diff --git a/drivers/gpu/drm/renesas/rz-du/Makefile b/drivers/gpu/drm/renesas/rz-du/Makefile
index 2987900ea6b6..46decb7ac4f1 100644
--- a/drivers/gpu/drm/renesas/rz-du/Makefile
+++ b/drivers/gpu/drm/renesas/rz-du/Makefile
@@ -8,3 +8,4 @@ rzg2l-du-drm-$(CONFIG_VIDEO_RENESAS_VSP1)	+= rzg2l_du_vsp.o
 obj-$(CONFIG_DRM_RZG2L_DU)		+= rzg2l-du-drm.o
 
 obj-$(CONFIG_DRM_RZG2L_MIPI_DSI)	+= rzg2l_mipi_dsi.o
+obj-$(CONFIG_DRM_RZG3L_LVDS)		+= rzg3l_lvds.o
diff --git a/drivers/gpu/drm/renesas/rz-du/rzg3l_lvds.c b/drivers/gpu/drm/renesas/rz-du/rzg3l_lvds.c
new file mode 100644
index 000000000000..6100888ea728
--- /dev/null
+++ b/drivers/gpu/drm/renesas/rz-du/rzg3l_lvds.c
@@ -0,0 +1,285 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * RZ/G3L LVDS Encoder Driver
+ *
+ * Copyright (C) 2026 Renesas Electronics Corporation
+ */
+
+#include <linux/bitfield.h>
+#include <linux/delay.h>
+#include <linux/io.h>
+#include <linux/media-bus-format.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/of_graph.h>
+#include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
+#include <linux/regmap.h>
+#include <linux/reset.h>
+
+#include <drm/drm_atomic.h>
+#include <drm/drm_atomic_helper.h>
+#include <drm/drm_bridge.h>
+#include <drm/drm_of.h>
+#include <drm/drm_panel.h>
+#include <drm/drm_probe_helper.h>
+
+#include "rzg3l_lvds_regs.h"
+
+enum rzg3l_lvds_mode {
+	RZG3L_LVDS_MODE_JEIDA = 0,
+	RZG3L_LVDS_MODE_JEIDA_MIRROR = 1,
+	RZG3L_LVDS_MODE_MODE2 = 2,
+	RZG3L_LVDS_MODE_MODE2_MIRROR = 3,
+	RZG3L_LVDS_MODE_VESA = 4,
+	RZG3L_LVDS_MODE_VESA_MIRROR = 5,
+	RZG3L_LVDS_MODE_MODE6 = 6,
+	RZG3L_LVDS_MODE_MODE6_MIRROR = 7,
+};
+
+struct rzg3l_lvds {
+	struct device *dev;
+	struct reset_control *prstc;
+	struct reset_control *lvd_rstc;
+	struct regmap *regmap;
+	struct drm_bridge bridge;
+};
+
+#define bridge_to_rzg3l_lvds(b) \
+	container_of(b, struct rzg3l_lvds, bridge)
+
+static const struct regmap_config rzg3l_lvds_regmap_config = {
+	.reg_bits = 32,
+	.val_bits = 32,
+	.reg_stride = 4,
+	.max_register = LVDS_0_CTL_OFFSET,
+};
+
+/* -----------------------------------------------------------------------------
+ * Bridge
+ */
+
+static void rzg3l_lvds_atomic_enable(struct drm_bridge *bridge,
+				     struct drm_atomic_commit *state)
+{
+	struct rzg3l_lvds *lvds = bridge_to_rzg3l_lvds(bridge);
+	const struct drm_bridge_state *bridge_state;
+	u32 fmt;
+
+	/* Get the LVDS format from the bridge state. */
+	bridge_state = drm_atomic_get_new_bridge_state(state, bridge);
+	if (WARN_ON(!bridge_state))
+		return;
+
+	switch (bridge_state->output_bus_cfg.format) {
+	case MEDIA_BUS_FMT_RGB888_1X7X4_JEIDA:
+		fmt = RZG3L_LVDS_MODE_JEIDA;
+		break;
+	case MEDIA_BUS_FMT_RGB888_1X7X4_SPWG:
+		fmt = RZG3L_LVDS_MODE_VESA;
+		break;
+	default:
+		fmt = RZG3L_LVDS_MODE_VESA;
+		dev_warn(lvds->dev, "Unsupported bus fmt 0x%04x\n",
+			 bridge_state->output_bus_cfg.format);
+		break;
+	}
+
+	if (WARN_ON(pm_runtime_get_sync(lvds->dev) < 0))
+		return;
+
+	regmap_update_bits(lvds->regmap, LVDS_0_PHY_OFFSET,
+			   LVDS_0_PHY_CH_EN_BGR, LVDS_0_PHY_CH_EN_BGR);
+	fsleep(20);
+
+	regmap_update_bits(lvds->regmap, LVDS_0_PHY_OFFSET,
+			   LVDS_0_PHY_CH_EN_LDO, LVDS_0_PHY_CH_EN_LDO);
+	fsleep(10);
+
+	regmap_write(lvds->regmap, LVDS_CMN, LVDS_CMN_RST_PHY0_SEL);
+	regmap_update_bits(lvds->regmap, LVDS_0_CTL_OFFSET,
+			   LVDS_0_CTL_FMT_SEL0_MSK,
+			   FIELD_PREP(LVDS_0_CTL_FMT_SEL0_MSK, fmt));
+	regmap_update_bits(lvds->regmap, LVDS_0_PHY_OFFSET,
+			   LVDS_0_PHY_CH_IO_EN0_MSK, LVDS_0_PHY_CH_IO_EN0);
+	regmap_write(lvds->regmap, LVDS_CMN,
+		     LVDS_CMN_RST_PHY0_SEL | LVDS_CMN_PHY_RESET);
+	fsleep(100);
+}
+
+static void rzg3l_lvds_atomic_disable(struct drm_bridge *bridge,
+				      struct drm_atomic_commit *state)
+{
+	struct rzg3l_lvds *lvds = bridge_to_rzg3l_lvds(bridge);
+
+	regmap_update_bits(lvds->regmap, LVDS_CMN, LVDS_CMN_PHY_RESET, 0);
+	regmap_update_bits(lvds->regmap, LVDS_0_PHY_OFFSET,
+			   LVDS_0_PHY_CH_IO_EN0_MSK, 0);
+	regmap_update_bits(lvds->regmap, LVDS_0_PHY_OFFSET,
+			   LVDS_0_PHY_CH_EN_LDO, 0);
+	regmap_update_bits(lvds->regmap, LVDS_0_PHY_OFFSET,
+			   LVDS_0_PHY_CH_EN_BGR, 0);
+
+	pm_runtime_put(lvds->dev);
+}
+
+static int rzg3l_lvds_attach(struct drm_bridge *bridge,
+			     struct drm_encoder *encoder,
+			     enum drm_bridge_attach_flags flags)
+{
+	struct rzg3l_lvds *lvds = bridge_to_rzg3l_lvds(bridge);
+
+	return drm_bridge_attach(encoder, lvds->bridge.next_bridge, bridge, flags);
+}
+
+static enum drm_mode_status
+rzg3l_lvds_bridge_mode_valid(struct drm_bridge *bridge,
+			     const struct drm_display_info *info,
+			     const struct drm_display_mode *mode)
+{
+	if (mode->clock > 87000)
+		return MODE_CLOCK_HIGH;
+
+	if (mode->clock < 25000)
+		return MODE_CLOCK_LOW;
+
+	return MODE_OK;
+}
+
+static const struct drm_bridge_funcs rzg3l_lvds_bridge_ops = {
+	.attach = rzg3l_lvds_attach,
+	.atomic_duplicate_state = drm_atomic_helper_bridge_duplicate_state,
+	.atomic_destroy_state = drm_atomic_helper_bridge_destroy_state,
+	.atomic_create_state = drm_atomic_helper_bridge_create_state,
+	.atomic_enable = rzg3l_lvds_atomic_enable,
+	.atomic_disable = rzg3l_lvds_atomic_disable,
+	.mode_valid = rzg3l_lvds_bridge_mode_valid,
+};
+
+/* -----------------------------------------------------------------------------
+ * Power Management
+ */
+
+static int rzg3l_lvds_pm_runtime_suspend(struct device *dev)
+{
+	struct rzg3l_lvds *lvds = dev_get_drvdata(dev);
+	struct reset_control_bulk_data resets[] = {
+		{ .rstc = lvds->lvd_rstc },
+		{ .rstc = lvds->prstc },
+	};
+
+	return reset_control_bulk_assert(ARRAY_SIZE(resets), resets);
+}
+
+static int rzg3l_lvds_pm_runtime_resume(struct device *dev)
+{
+	struct rzg3l_lvds *lvds = dev_get_drvdata(dev);
+	struct reset_control_bulk_data resets[] = {
+		{ .rstc = lvds->lvd_rstc },
+		{ .rstc = lvds->prstc },
+	};
+
+	return reset_control_bulk_deassert(ARRAY_SIZE(resets), resets);
+}
+
+static DEFINE_RUNTIME_DEV_PM_OPS(rzg3l_lvds_pm_ops,
+				 rzg3l_lvds_pm_runtime_suspend,
+				 rzg3l_lvds_pm_runtime_resume, NULL);
+
+/* -----------------------------------------------------------------------------
+ * Probe & Remove
+ */
+
+static int rzg3l_lvds_probe(struct platform_device *pdev)
+{
+	struct reset_control *rstc, *arstc;
+	struct device *dev = &pdev->dev;
+	struct rzg3l_lvds *lvds;
+	void __iomem *base;
+	int ret;
+
+	lvds = devm_drm_bridge_alloc(dev, struct rzg3l_lvds, bridge,
+				     &rzg3l_lvds_bridge_ops);
+	if (IS_ERR(lvds))
+		return PTR_ERR(lvds);
+
+	lvds->dev = dev;
+	lvds->bridge.of_node = pdev->dev.of_node;
+
+	base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(base))
+		return PTR_ERR(base);
+
+	lvds->regmap = devm_regmap_init_mmio(dev, base, &rzg3l_lvds_regmap_config);
+	if (IS_ERR(lvds->regmap))
+		return dev_err_probe(dev, PTR_ERR(lvds->regmap),
+				     "failed to init regmap\n");
+
+	rstc = devm_reset_control_get_exclusive(dev, "rst");
+	if (IS_ERR(rstc))
+		return dev_err_probe(dev, PTR_ERR(rstc), "failed to get rst\n");
+
+	arstc = devm_reset_control_get_exclusive(dev, "arst");
+	if (IS_ERR(arstc))
+		return dev_err_probe(dev, PTR_ERR(arstc),
+				     "failed to get arst\n");
+
+	lvds->prstc = devm_reset_control_get_exclusive(dev, "prst");
+	if (IS_ERR(lvds->prstc))
+		return dev_err_probe(dev, PTR_ERR(lvds->prstc),
+				     "failed to get prst\n");
+
+	lvds->lvd_rstc = devm_reset_control_get_exclusive(dev, "lvdrst");
+	if (IS_ERR(lvds->lvd_rstc))
+		return dev_err_probe(dev, PTR_ERR(lvds->lvd_rstc),
+				     "failed to get core reset\n");
+
+	platform_set_drvdata(pdev, lvds);
+	ret = devm_pm_runtime_enable(dev);
+	if (ret)
+		return dev_err_probe(dev, ret, "Failed to enable Runtime PM\n");
+
+	lvds->bridge.next_bridge = devm_drm_of_get_bridge(dev, dev->of_node, 1, 0);
+	if (IS_ERR(lvds->bridge.next_bridge))
+		return dev_err_probe(dev, PTR_ERR(lvds->bridge.next_bridge),
+				     "failed to get next bridge\n");
+
+	ret = reset_control_assert(rstc);
+	if (ret < 0)
+		return ret;
+
+	ret = reset_control_assert(arstc);
+	if (ret < 0)
+		return ret;
+
+	ret = devm_drm_bridge_add(dev, &lvds->bridge);
+	if (ret)
+		return dev_err_probe(dev, ret,
+				     "Failed to register drm bridge\n");
+
+	return ret;
+}
+
+static const struct of_device_id rzg3l_lvds_of_table[] = {
+	{ .compatible = "renesas,r9a08g046-lvds" },
+	{ /* sentinel */ }
+};
+
+MODULE_DEVICE_TABLE(of, rzg3l_lvds_of_table);
+
+static struct platform_driver rzg3l_lvds_platform_driver = {
+	.probe		= rzg3l_lvds_probe,
+	.driver		= {
+		.name	= "rzg3l-lvds",
+		.pm	= pm_ptr(&rzg3l_lvds_pm_ops),
+		.of_match_table = rzg3l_lvds_of_table,
+	},
+};
+
+module_platform_driver(rzg3l_lvds_platform_driver);
+
+MODULE_AUTHOR("Biju Das <biju.das.jz@bp.renesas.com>");
+MODULE_AUTHOR("Tommaso Merciai <tommaso.merciai.xr@bp.renesas.com>");
+MODULE_DESCRIPTION("Renesas RZ/G3L LVDS Encoder Driver");
+MODULE_LICENSE("GPL");
diff --git a/drivers/gpu/drm/renesas/rz-du/rzg3l_lvds_regs.h b/drivers/gpu/drm/renesas/rz-du/rzg3l_lvds_regs.h
new file mode 100644
index 000000000000..3dca3b630818
--- /dev/null
+++ b/drivers/gpu/drm/renesas/rz-du/rzg3l_lvds_regs.h
@@ -0,0 +1,26 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * RZ/G3L LVDS Interface Registers Definitions
+ *
+ * Copyright (C) 2026 Renesas Electronics Corporation
+ *
+ */
+
+#ifndef __RZG3L_LVDS_REGS_H__
+#define __RZG3L_LVDS_REGS_H__
+
+#define LVDS_CMN			0x00
+#define LVDS_CMN_RST_PHY0_SEL		(1 << 24)
+#define LVDS_CMN_RST_PHY0_SEL_CH0	(1 << 24)
+#define LVDS_CMN_PHY_RESET		(1 << 0)
+
+#define LVDS_0_PHY_OFFSET		0x10
+#define LVDS_0_PHY_CH_IO_EN0_MSK	(0x1f)
+#define LVDS_0_PHY_CH_IO_EN0		(LVDS_0_PHY_CH_IO_EN0_MSK << 0)
+#define LVDS_0_PHY_CH_EN_BGR		BIT(8)
+#define LVDS_0_PHY_CH_EN_LDO		BIT(9)
+
+#define LVDS_0_CTL_OFFSET		0x14
+#define LVDS_0_CTL_FMT_SEL0_MSK		GENMASK(23, 20)
+
+#endif /* __RZG3L_LVDS_REGS_H__ */
-- 
2.43.0

Re: [PATCH v4 2/2] drm: renesas: rz-du: Add support for RZ/G3L LVDS encoder

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 2 potential issue(s) to consider:
- [High] Sleeping functions called in atomic context during bridge enable
- [High] Early returns in `atomic_enable` cause unbalanced PM counter and unpowered hardware access in `atomic_disable`
--

commit 0eae00dcaa6988008a1dca84233d19bc97469ed0
Author: Biju Das <biju.das.jz@bp.renesas.com>

drm: renesas: rz-du: Add support for RZ/G3L LVDS encoder

Adds support for the RZ/G3L LVDS encoder driver operating in single-link
mode with 4 lanes. It supports pixel clocks from 25 to 87 MHz and shares
peripherals with MIPI-DSI.

> diff --git a/drivers/gpu/drm/renesas/rz-du/rzg3l_lvds.c b/drivers/gpu/drm/renesas/rz-du/rzg3l_lvds.c
> new file mode 100644
> index 0000000000000..6100888ea7284
> --- /dev/null
> +++ b/drivers/gpu/drm/renesas/rz-du/rzg3l_lvds.c
[ ... ]
> @@ -0,0 +1,285 @@
> +static void rzg3l_lvds_atomic_enable(struct drm_bridge *bridge,
> +				     struct drm_atomic_commit *state)
> +{
> +	struct rzg3l_lvds *lvds = bridge_to_rzg3l_lvds(bridge);
> +	const struct drm_bridge_state *bridge_state;
> +	u32 fmt;
> +
> +	/* Get the LVDS format from the bridge state. */
> +	bridge_state = drm_atomic_get_new_bridge_state(state, bridge);
> +	if (WARN_ON(!bridge_state))
> +		return;

[Severity: High]
If drm_atomic_get_new_bridge_state() returns NULL and takes this early return,
will rzg3l_lvds_atomic_disable() later execute unconditionally and access
unpowered hardware registers or cause a runtime PM usage counter underflow?
Since atomic_enable returns void, the DRM core might still consider the bridge
enabled.

> +
> +	switch (bridge_state->output_bus_cfg.format) {
> +	case MEDIA_BUS_FMT_RGB888_1X7X4_JEIDA:
> +		fmt = RZG3L_LVDS_MODE_JEIDA;
> +		break;
> +	case MEDIA_BUS_FMT_RGB888_1X7X4_SPWG:
> +		fmt = RZG3L_LVDS_MODE_VESA;
> +		break;
> +	default:
> +		fmt = RZG3L_LVDS_MODE_VESA;
> +		dev_warn(lvds->dev, "Unsupported bus fmt 0x%04x\n",
> +			 bridge_state->output_bus_cfg.format);
> +		break;
> +	}
> +
> +	if (WARN_ON(pm_runtime_get_sync(lvds->dev) < 0))
> +		return;

[Severity: High]
Similarly, if pm_runtime_get_sync() fails, returning early here leaves the
device unpowered. When rzg3l_lvds_atomic_disable() is called during teardown,
could this lead to a bus fault from accessing unpowered MMIO registers and
an unbalanced pm_runtime_put() counter?

[Severity: High]
Also, since atomic_enable callbacks run in an atomic commit context where
sleeping is forbidden, is it safe to use pm_runtime_get_sync() here? This
function blocks and sleeps while waiting for the device to resume, which might
cause a scheduling while atomic regression.

> +
> +	regmap_update_bits(lvds->regmap, LVDS_0_PHY_OFFSET,
> +			   LVDS_0_PHY_CH_EN_BGR, LVDS_0_PHY_CH_EN_BGR);
> +	fsleep(20);
> +
> +	regmap_update_bits(lvds->regmap, LVDS_0_PHY_OFFSET,
> +			   LVDS_0_PHY_CH_EN_LDO, LVDS_0_PHY_CH_EN_LDO);
> +	fsleep(10);

[Severity: High]
Because this is an atomic commit path, delay functions that can sleep like
fsleep() are unsafe. Could these fsleep() calls (which map to usleep_range()
or msleep()) lead to scheduling while atomic bugs? Would udelay() or ndelay()
be more appropriate for these hardware delays?

> +
> +	regmap_write(lvds->regmap, LVDS_CMN, LVDS_CMN_RST_PHY0_SEL);
> +	regmap_update_bits(lvds->regmap, LVDS_0_CTL_OFFSET,
> +			   LVDS_0_CTL_FMT_SEL0_MSK,
> +			   FIELD_PREP(LVDS_0_CTL_FMT_SEL0_MSK, fmt));
> +	regmap_update_bits(lvds->regmap, LVDS_0_PHY_OFFSET,
> +			   LVDS_0_PHY_CH_IO_EN0_MSK, LVDS_0_PHY_CH_IO_EN0);
> +	regmap_write(lvds->regmap, LVDS_CMN,
> +		     LVDS_CMN_RST_PHY0_SEL | LVDS_CMN_PHY_RESET);
> +	fsleep(100);

[Severity: High]
Could this fsleep(100) call also sleep in this atomic context?

> +}

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260619101026.323633-1-biju.das.jz@bp.renesas.com?part=2

RE: [PATCH v4 2/2] drm: renesas: rz-du: Add support for RZ/G3L LVDS encoder

[Biju Das]

Hi sashiko,

Thanks for the review.

> -----Original Message-----
> From: dri-devel <dri-devel-bounces@lists.freedesktop.org> On Behalf Of sashiko-bot@kernel.org
> Sent: 19 June 2026 11:20
> To: biju.das.au <biju.das.au@gmail.com>
> Cc: wsa+renesas <wsa+renesas@sang-engineering.com>; dri-devel@lists.freedesktop.org
> Subject: Re: [PATCH v4 2/2] drm: renesas: rz-du: Add support for RZ/G3L LVDS encoder
> 
> Thank you for your contribution! Sashiko AI review found 2 potential issue(s) to consider:
> - [High] Sleeping functions called in atomic context during bridge enable

Can you please let me know which is atomic context here?

Probe: No sleeping context
[   19.611090]  rzg3l_lvds_atomic_enable+0x18/0x16c [rzg3l_lvds] (P)
[   19.611106]  drm_atomic_bridge_chain_enable+0x60/0xb0 [drm]
[   19.611287]  drm_atomic_helper_commit_encoder_bridge_enable+0xdc/0x140 [drm_kms_helper]
[   19.611386]  drm_atomic_helper_commit_tail_rpm+0x80/0xe0 [drm_kms_helper]
[   19.611456]  commit_tail+0xa4/0x1a4 [drm_kms_helper]
[   19.611524]  drm_atomic_helper_commit+0x17c/0x1b0 [drm_kms_helper]
[   19.611593]  drm_atomic_commit+0x8c/0xcc [drm]
[   19.611766]  drm_client_modeset_commit_atomic+0x224/0x294 [drm]
[   19.611937]  drm_client_modeset_commit_locked+0x5c/0x188 [drm]
[   19.612108]  drm_client_modeset_commit+0x2c/0x58 [drm]
[   19.612280]  __drm_fb_helper_restore_fbdev_mode_unlocked.part.0+0x90/0xa0 [drm_kms_helper]
[   19.612348]  drm_fb_helper_set_par+0x68/0x84 [drm_kms_helper]
[   19.612417]  fbcon_init+0x4fc/0x520
[   19.612435]  visual_init+0xb4/0x104
[   19.612449]  do_bind_con_driver.isra.0+0x1c4/0x374
[   19.612462]  do_take_over_console+0x1a0/0x200
[   19.612474]  do_fbcon_takeover+0x6c/0xe0
[   19.612485]  fbcon_fb_registered+0x1dc/0x1e0
[   19.612497]  do_register_framebuffer+0x198/0x254
[   19.612507]  register_framebuffer+0x2c/0x50
[   19.612516]  __drm_fb_helper_initial_config_and_unlock+0x330/0x5cc [drm_kms_helper]
[   19.612583]  drm_fb_helper_initial_config+0x44/0x54 [drm_kms_helper]
[   19.612651]  drm_fbdev_client_hotplug+0x7c/0xdc [drm_client_lib]
[   19.612669]  drm_client_register+0x58/0x9c [drm]
[   19.612839]  drm_fbdev_client_setup+0xa4/0xce0 [drm_client_lib]
[   19.612853]  drm_client_setup+0xb0/0xe0 [drm_client_lib]
[   19.612863]  rzg2l_du_probe+0x134/0x174 [rzg2l_du_drm]

Suspend to RAM: no sleeping context
[   79.238581]  rzg3l_lvds_atomic_enable+0x18/0x16c [rzg3l_lvds] (P)
[   79.238595]  drm_atomic_bridge_chain_enable+0x60/0xb0 [drm]
[   79.238764]  drm_atomic_helper_commit_encoder_bridge_enable+0xdc/0x140 [drm_kms_helper]
[   79.238876]  drm_atomic_helper_commit_tail_rpm+0x80/0xe0 [drm_kms_helper]
[   79.238947]  commit_tail+0xa4/0x1a4 [drm_kms_helper]
[   79.239014]  drm_atomic_helper_commit+0x17c/0x1b0 [drm_kms_helper]
[   79.239080]  drm_atomic_commit+0x8c/0xcc [drm]
[   79.239251]  drm_atomic_helper_commit_duplicated_state+0x134/0x148 [drm_kms_helper]
[   79.239319]  drm_atomic_helper_resume+0xac/0x19c [drm_kms_helper]
[   79.239389]  drm_mode_config_helper_resume+0x24/0xc0 [drm_kms_helper]
[   79.239459]  rzg2l_du_pm_resume+0x18/0x24 [rzg2l_du_drm]
[   79.239479]  device_resume+0xc8/0x1c4
[   79.239496]  dpm_resume+0x198/0x1b8
[   79.239505]  dpm_resume_end+0x18/0x34
[   79.239514]  suspend_devices_and_enter+0x224/0x590
[   79.239530]  pm_suspend+0x194/0x1c0
[   79.239539]  state_store+0x80/0xf4
[   79.239549]  kobj_attr_store+0x18/0x34
[   79.239563]  sysfs_kf_write+0x7c/0xa0
[   79.239575]  kernfs_fop_write_iter+0x130/0x200

Hotplug:

]  rzg3l_lvds_atomic_enable+0x18/0x16c [rzg3l_lvds] (P)
[  235.264272]  drm_atomic_bridge_chain_enable+0x60/0xb0 [drm]
[  235.272544]  drm_atomic_helper_commit_encoder_bridge_enable+0xdc/0x140 [drm_kms_helper]
[  235.281610]  drm_atomic_helper_commit_tail_rpm+0x80/0xe0 [drm_kms_helper]
[  235.289443]  commit_tail+0xa4/0x1a4 [drm_kms_helper]
[  235.295459]  commit_work+0x14/0x20 [drm_kms_helper]
[  235.301397]  process_one_work+0x154/0x290
[  235.305625]  worker_thread+0x184/0x2f4
[  235.309571]  kthread+0x118/0x130
[  235.312982]  ret_from_fork+0x10/0x20
 


> - [High] Early returns in `atomic_enable` cause unbalanced PM counter and unpowered hardware access in
> `atomic_disable`
> --

So far during testing no issues found, WARN_ON is added to find
any such issues in future.

Cheers,
Biju