[PATCH 0/2] i.MX91/93 parallel display bridge

[PATCH 0/2] i.MX91/93 parallel display bridge

[Alexander Stein]

Hi,

i.MX91/93 support a parallel display interface. There is a single register
for configuring the output format. There is not much documentation, but
apparently this does some internal conversion.
Add a bridge driver (similar to fsl-ldb.c) for connecting a bridge/panel
to lcdif.
I'm a bit unsure about the name. There is no dedicated IP, according to
reference manual, just that single register. I would also agree
to imx9-dpi or imx93-dpi.
Note: It's only applicable to i.MX91/93, but not i.MX95!

Tested on TQMa9352 on MBa91xxCA

Best regards,
Alexander

Alexander Stein (2):
  dt-bindings: display: bridge: ldb: Implement simple Freescale
    i.MX91/93 DPI bridge
  drm: bridge: imx9-parallel-disp-fmt: add i.MX91/93 parallel display
    bridge

 .../bridge/fsl,imx9-parallel-disp-fmt.yaml    |  78 +++++++
 drivers/gpu/drm/bridge/Kconfig                |  10 +
 drivers/gpu/drm/bridge/Makefile               |   1 +
 .../gpu/drm/bridge/imx9-parallel-disp-fmt.c   | 213 ++++++++++++++++++
 4 files changed, 302 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/display/bridge/fsl,imx9-parallel-disp-fmt.yaml
 create mode 100644 drivers/gpu/drm/bridge/imx9-parallel-disp-fmt.c

-- 
2.34.1

[PATCH 1/2] dt-bindings: display: bridge: ldb: Implement simple Freescale i.MX91/93 DPI bridge

[Alexander Stein]

The i.MX91/93 contains a single syscon registers which is responsible
for configuring DPI output format. Add DT binding which represents
this configuration as a bridge.

Signed-off-by: Alexander Stein <alexander.stein@ew.tq-group.com>
---
 .../bridge/fsl,imx9-parallel-disp-fmt.yaml    | 78 +++++++++++++++++++
 1 file changed, 78 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/display/bridge/fsl,imx9-parallel-disp-fmt.yaml

diff --git a/Documentation/devicetree/bindings/display/bridge/fsl,imx9-parallel-disp-fmt.yaml b/Documentation/devicetree/bindings/display/bridge/fsl,imx9-parallel-disp-fmt.yaml
new file mode 100644
index 0000000000000..54cb73b59b1eb
--- /dev/null
+++ b/Documentation/devicetree/bindings/display/bridge/fsl,imx9-parallel-disp-fmt.yaml
@@ -0,0 +1,78 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/display/bridge/fsl,imx9-parallel-disp-fmt.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Freescale i.MX91/93 DPI bridge
+
+maintainers:
+  - Alexander Stein <alexander.stein@ew.tq-group.com>
+
+description: |
+  The i.MX91/93 mediamix contains a single register which is responsible
+  for configuring the parallel display output format. This describes
+  this registers as bridge within the DT.
+
+properties:
+  compatible:
+    const: fsl,imx9-parallel-display-format
+
+  reg:
+    maxItems: 1
+
+  ports:
+    $ref: /schemas/graph.yaml#/properties/ports
+
+    properties:
+      port@0:
+        $ref: /schemas/graph.yaml#/properties/port
+        description: Video port for DPI input.
+
+      port@1:
+        $ref: /schemas/graph.yaml#/properties/port
+        description: Video port for DPI output (panel or bridge).
+
+    required:
+      - port@0
+      - port@1
+
+required:
+  - compatible
+  - reg
+  - ports
+
+additionalProperties: false
+
+examples:
+  - |
+    blk-ctrl {
+        #address-cells = <1>;
+        #size-cells = <1>;
+
+        bridge@60 {
+            compatible = "fsl,imx9-parallel-display-format";
+            reg = <0x60 0x4>;
+            status = "disabled";
+
+            ports {
+                #address-cells = <1>;
+                #size-cells = <0>;
+
+                port@0 {
+                    reg = <0>;
+
+                    dpi_from_lcdif: endpoint {
+                        remote-endpoint = <&lcdif_to_dpi>;
+                    };
+                };
+
+                port@1 {
+                    reg = <1>;
+
+                    dpi_out: endpoint {
+                    };
+                };
+            };
+        };
+    };
-- 
2.34.1

Re: [PATCH 1/2] dt-bindings: display: bridge: ldb: Implement simple Freescale i.MX91/93 DPI bridge

[Frank Li]

On Tue, Feb 11, 2025 at 09:41:18AM +0100, Alexander Stein wrote:
> The i.MX91/93 contains a single syscon registers which is responsible
> for configuring DPI output format. Add DT binding which represents
> this configuration as a bridge.
>
> Signed-off-by: Alexander Stein <alexander.stein@ew.tq-group.com>
> ---
>  .../bridge/fsl,imx9-parallel-disp-fmt.yaml    | 78 +++++++++++++++++++
>  1 file changed, 78 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/display/bridge/fsl,imx9-parallel-disp-fmt.yaml
>
> diff --git a/Documentation/devicetree/bindings/display/bridge/fsl,imx9-parallel-disp-fmt.yaml b/Documentation/devicetree/bindings/display/bridge/fsl,imx9-parallel-disp-fmt.yaml
> new file mode 100644
> index 0000000000000..54cb73b59b1eb
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/display/bridge/fsl,imx9-parallel-disp-fmt.yaml
> @@ -0,0 +1,78 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/display/bridge/fsl,imx9-parallel-disp-fmt.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Freescale i.MX91/93 DPI bridge
> +
> +maintainers:
> +  - Alexander Stein <alexander.stein@ew.tq-group.com>
> +
> +description: |

Needn't |

> +  The i.MX91/93 mediamix contains a single register which is responsible
> +  for configuring the parallel display output format. This describes
> +  this registers as bridge within the DT.
> +
> +properties:
> +  compatible:
> +    const: fsl,imx9-parallel-display-format


look like it should belong a property in fsl,imx8mm-disp-blk-ctrl.yaml.

Rob provide similar suggestion at
https://lore.kernel.org/imx/20250203220655.GA123074-robh@kernel.org/

Or at least, uplayer mfd yaml should link to this file.

Frank
> +
> +  reg:
> +    maxItems: 1
> +
> +  ports:
> +    $ref: /schemas/graph.yaml#/properties/ports
> +
> +    properties:
> +      port@0:
> +        $ref: /schemas/graph.yaml#/properties/port
> +        description: Video port for DPI input.
> +
> +      port@1:
> +        $ref: /schemas/graph.yaml#/properties/port
> +        description: Video port for DPI output (panel or bridge).
> +
> +    required:
> +      - port@0
> +      - port@1
> +
> +required:
> +  - compatible
> +  - reg
> +  - ports
> +
> +additionalProperties: false
> +
> +examples:
> +  - |
> +    blk-ctrl {
> +        #address-cells = <1>;
> +        #size-cells = <1>;
> +
> +        bridge@60 {
> +            compatible = "fsl,imx9-parallel-display-format";
> +            reg = <0x60 0x4>;
> +            status = "disabled";
> +
> +            ports {
> +                #address-cells = <1>;
> +                #size-cells = <0>;
> +
> +                port@0 {
> +                    reg = <0>;
> +
> +                    dpi_from_lcdif: endpoint {
> +                        remote-endpoint = <&lcdif_to_dpi>;
> +                    };
> +                };
> +
> +                port@1 {
> +                    reg = <1>;
> +
> +                    dpi_out: endpoint {
> +                    };
> +                };
> +            };
> +        };
> +    };
> --
> 2.34.1
>

[PATCH 2/2] drm: bridge: imx9-parallel-disp-fmt: add i.MX91/93 parallel display bridge

[Alexander Stein]

i.MX91/93 have a single register specifying parallel display output
format. Add a bridge driver for setting the corresponding format.
Currently only RGB565, RGB666 and RGB888 output is supported.

Signed-off-by: Alexander Stein <alexander.stein@ew.tq-group.com>
---
 drivers/gpu/drm/bridge/Kconfig                |  10 +
 drivers/gpu/drm/bridge/Makefile               |   1 +
 .../gpu/drm/bridge/imx9-parallel-disp-fmt.c   | 213 ++++++++++++++++++
 3 files changed, 224 insertions(+)
 create mode 100644 drivers/gpu/drm/bridge/imx9-parallel-disp-fmt.c

diff --git a/drivers/gpu/drm/bridge/Kconfig b/drivers/gpu/drm/bridge/Kconfig
index 6b4664d91faa8..8b69977787883 100644
--- a/drivers/gpu/drm/bridge/Kconfig
+++ b/drivers/gpu/drm/bridge/Kconfig
@@ -90,6 +90,16 @@ config DRM_FSL_LDB
 	help
 	  Support for i.MX8MP DPI-to-LVDS on-SoC encoder.
 
+config DRM_IMX9_PARALLEL_DISPLAY_FORMAT
+	tristate "Support for i.MX93 parallel display format"
+	depends on OF && MFD_SYSCON
+	depends on ARCH_MXC || COMPILE_TEST
+	select DRM_KMS_HELPER
+	select DRM_PANEL_BRIDGE
+	help
+	  Support for internal parallel display format configuration
+	  found on i.MX91 and i.MX93 processors.
+
 config DRM_ITE_IT6263
 	tristate "ITE IT6263 LVDS/HDMI bridge"
 	depends on OF
diff --git a/drivers/gpu/drm/bridge/Makefile b/drivers/gpu/drm/bridge/Makefile
index 97304b429a530..ee3406fed880f 100644
--- a/drivers/gpu/drm/bridge/Makefile
+++ b/drivers/gpu/drm/bridge/Makefile
@@ -6,6 +6,7 @@ obj-$(CONFIG_DRM_CHRONTEL_CH7033) += chrontel-ch7033.o
 obj-$(CONFIG_DRM_CROS_EC_ANX7688) += cros-ec-anx7688.o
 obj-$(CONFIG_DRM_DISPLAY_CONNECTOR) += display-connector.o
 obj-$(CONFIG_DRM_FSL_LDB) += fsl-ldb.o
+obj-$(CONFIG_DRM_IMX9_PARALLEL_DISPLAY_FORMAT) += imx9-parallel-disp-fmt.o
 obj-$(CONFIG_DRM_ITE_IT6263) += ite-it6263.o
 obj-$(CONFIG_DRM_ITE_IT6505) += ite-it6505.o
 obj-$(CONFIG_DRM_LONTIUM_LT8912B) += lontium-lt8912b.o
diff --git a/drivers/gpu/drm/bridge/imx9-parallel-disp-fmt.c b/drivers/gpu/drm/bridge/imx9-parallel-disp-fmt.c
new file mode 100644
index 0000000000000..c37bdda53377c
--- /dev/null
+++ b/drivers/gpu/drm/bridge/imx9-parallel-disp-fmt.c
@@ -0,0 +1,213 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) 2022 NXP
+ * Copyright (c) 2026 TQ-Systems GmbH <linux@ew.tq-group.com>,
+ * D-82229 Seefeld, Germany.
+ * Author: Alexander Stein
+ */
+
+#include <linux/media-bus-format.h>
+#include <linux/mfd/syscon.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <drm/drm_atomic_helper.h>
+#include <drm/drm_bridge.h>
+#include <drm/drm_of.h>
+#include <drm/drm_panel.h>
+
+#define DISPLAY_MUX_CTRL		0x60
+#define  PARALLEL_DISP_FORMAT		GENMASK(10, 8)
+#define  FORMAT_RGB888_TO_RGB888	FIELD_PREP(PARALLEL_DISP_FORMAT, 0)
+#define  FORMAT_RGB888_TO_RGB666	FIELD_PREP(PARALLEL_DISP_FORMAT, 1)
+#define  FORMAT_RGB565_TO_RGB565	FIELD_PREP(PARALLEL_DISP_FORMAT, 2)
+#define  FORMAT_RGB555_TO_RGB555	FIELD_PREP(PARALLEL_DISP_FORMAT, 3)
+#define  FORMAT_YUV_TO_YCBCR24		FIELD_PREP(PARALLEL_DISP_FORMAT, 4)
+#define  FORMAT_YUV_TO_YUV444		FIELD_PREP(PARALLEL_DISP_FORMAT, 5)
+
+struct imx9_pdf {
+	struct device *dev;
+	struct drm_bridge bridge;
+	struct drm_bridge *panel_bridge;
+	struct regmap *regmap;
+};
+
+static inline struct imx9_pdf *to_imx9_pdf(struct drm_bridge *bridge)
+{
+	return container_of(bridge, struct imx9_pdf, bridge);
+}
+
+static int imx9_pdf_attach(struct drm_bridge *bridge,
+	enum drm_bridge_attach_flags flags)
+{
+	struct imx9_pdf *pdf = to_imx9_pdf(bridge);
+
+	return drm_bridge_attach(bridge->encoder, pdf->panel_bridge,
+	       			 bridge, flags);
+}
+
+static void imx9_pdf_atomic_enable(struct drm_bridge *bridge,
+				   struct drm_bridge_state *old_bridge_state)
+{
+	struct imx9_pdf *pdf = to_imx9_pdf(bridge);
+	struct drm_atomic_state *state = old_bridge_state->base.state;
+	const struct drm_bridge_state *bridge_state;
+	u32 format;
+
+	/* Get the bus format from the bridge state. */
+	bridge_state = drm_atomic_get_new_bridge_state(state, bridge);
+
+	switch (bridge_state->output_bus_cfg.format) {
+	case MEDIA_BUS_FMT_RGB565_1X16:
+		format = FORMAT_RGB565_TO_RGB565;
+		break;
+	case MEDIA_BUS_FMT_RGB666_1X18:
+		format = FORMAT_RGB888_TO_RGB666;
+		break;
+	case MEDIA_BUS_FMT_RGB888_1X24:
+		format = FORMAT_RGB888_TO_RGB888;
+		break;
+	default:
+		/*
+		 * Some bridges still don't set the correct bus format.
+		 * Just print a warning.
+		 */
+		dev_warn(pdf->dev,
+			 "Unsupported bus format 0x%04x, please check output bridge driver\n",
+			 bridge_state->output_bus_cfg.format);
+		return;
+	}
+
+	regmap_update_bits(pdf->regmap, DISPLAY_MUX_CTRL, PARALLEL_DISP_FORMAT,
+			   format);
+}
+
+#define MAX_INPUT_SEL_FORMATS 2
+static u32 *
+imx9_pdf_atomic_get_input_bus_fmts(struct drm_bridge *bridge,
+				   struct drm_bridge_state *bridge_state,
+				   struct drm_crtc_state *crtc_state,
+				   struct drm_connector_state *conn_state,
+				   u32 output_fmt,
+				   unsigned int *num_input_fmts)
+{
+	u32 *input_fmts;
+
+	*num_input_fmts = 0;
+
+	input_fmts = kcalloc(MAX_INPUT_SEL_FORMATS, sizeof(*input_fmts),
+			     GFP_KERNEL);
+	if (!input_fmts)
+		return NULL;
+
+	input_fmts[0] = MEDIA_BUS_FMT_RGB888_1X24;
+	input_fmts[1] = MEDIA_BUS_FMT_RGB565_1X16;
+	*num_input_fmts = MAX_INPUT_SEL_FORMATS;
+
+	return input_fmts;
+}
+
+#define MAX_OUTPUT_SEL_FORMATS 3
+static u32 *
+imx9_pdf_atomic_get_output_bus_fmts(struct drm_bridge *bridge,
+				    struct drm_bridge_state *bridge_state,
+				    struct drm_crtc_state *crtc_state,
+				    struct drm_connector_state *conn_state,
+				    unsigned int *num_output_fmts)
+{
+	u32 *output_fmts;
+
+	*num_output_fmts = 0;
+
+	output_fmts = kcalloc(MAX_OUTPUT_SEL_FORMATS, sizeof(*output_fmts),
+			     GFP_KERNEL);
+	if (!output_fmts)
+		return NULL;
+
+	output_fmts[0] = MEDIA_BUS_FMT_RGB565_1X16;
+	output_fmts[1] = MEDIA_BUS_FMT_RGB666_1X18;
+	output_fmts[2] = MEDIA_BUS_FMT_RGB888_1X24;
+	*num_output_fmts = MAX_OUTPUT_SEL_FORMATS;
+
+	return output_fmts;
+}
+
+static enum drm_mode_status
+imx9_pdf_mode_valid(struct drm_bridge *bridge,
+		   const struct drm_display_info *info,
+		   const struct drm_display_mode *mode)
+{
+	if (mode->clock > 80000)
+		return MODE_CLOCK_HIGH;
+
+	return MODE_OK;
+}
+
+static const struct drm_bridge_funcs funcs = {
+	.attach = imx9_pdf_attach,
+	.atomic_enable = imx9_pdf_atomic_enable,
+	.atomic_duplicate_state = drm_atomic_helper_bridge_duplicate_state,
+	.atomic_destroy_state = drm_atomic_helper_bridge_destroy_state,
+	.atomic_get_input_bus_fmts = imx9_pdf_atomic_get_input_bus_fmts,
+	.atomic_get_output_bus_fmts = imx9_pdf_atomic_get_output_bus_fmts,
+	.atomic_reset = drm_atomic_helper_bridge_reset,
+	.mode_valid = imx9_pdf_mode_valid,
+};
+
+static int imx9_pdf_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct device_node *remote;
+	struct drm_panel *panel;
+	struct imx9_pdf *pdf;
+
+	pdf = devm_kzalloc(dev, sizeof(*pdf), GFP_KERNEL);
+	if (!pdf)
+		return -ENOMEM;
+
+	pdf->dev = &pdev->dev;
+	pdf->bridge.funcs = &funcs;
+	pdf->bridge.of_node = dev->of_node;
+	pdf->bridge.type = DRM_MODE_CONNECTOR_DPI;
+
+	pdf->regmap = syscon_node_to_regmap(dev->of_node->parent);
+	if (IS_ERR(pdf->regmap))
+		return dev_err_probe(dev, PTR_ERR(pdf->regmap),
+				     "failed to get regmap\n");
+
+	remote = of_graph_get_remote_node(dev->of_node, 1, 0);
+	panel = of_drm_find_panel(remote);
+	of_node_put(remote);
+	if (IS_ERR(panel))
+		return PTR_ERR(panel);
+
+	pdf->panel_bridge = devm_drm_panel_bridge_add(dev, panel);
+	if (IS_ERR(pdf->panel_bridge))
+		return PTR_ERR(pdf->panel_bridge);
+
+	platform_set_drvdata(pdev, pdf);
+
+	devm_drm_bridge_add(dev, &pdf->bridge);
+
+	return 0;
+}
+
+static const struct of_device_id imx9_pdf_dt_ids[] = {
+	{ .compatible = "fsl,imx9-parallel-display-format", },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, imx9_pdf_dt_ids);
+
+static struct platform_driver imx9_pdf_driver = {
+	.probe		= imx9_pdf_probe,
+	.driver		= {
+		.name		= "imx9-parallel-display-format",
+		.of_match_table	= imx9_pdf_dt_ids,
+	},
+};
+module_platform_driver(imx9_pdf_driver);
+
+MODULE_AUTHOR("Alexander Stein <alexander.stein@ew.tq-group.com>");
+MODULE_DESCRIPTION("i.MX91/i.MX93 parallel display format driver");
+MODULE_LICENSE("GPL v2");
-- 
2.34.1

Re: [PATCH 2/2] drm: bridge: imx9-parallel-disp-fmt: add i.MX91/93 parallel display bridge

[Frank Li]

On Tue, Feb 11, 2025 at 09:41:19AM +0100, Alexander Stein wrote:
> i.MX91/93 have a single register specifying parallel display output
> format. Add a bridge driver for setting the corresponding format.
> Currently only RGB565, RGB666 and RGB888 output is supported.
>
> Signed-off-by: Alexander Stein <alexander.stein@ew.tq-group.com>
> ---
>  drivers/gpu/drm/bridge/Kconfig                |  10 +
>  drivers/gpu/drm/bridge/Makefile               |   1 +
>  .../gpu/drm/bridge/imx9-parallel-disp-fmt.c   | 213 ++++++++++++++++++
>  3 files changed, 224 insertions(+)
>  create mode 100644 drivers/gpu/drm/bridge/imx9-parallel-disp-fmt.c
>
> diff --git a/drivers/gpu/drm/bridge/Kconfig b/drivers/gpu/drm/bridge/Kconfig
> index 6b4664d91faa8..8b69977787883 100644
> --- a/drivers/gpu/drm/bridge/Kconfig
> +++ b/drivers/gpu/drm/bridge/Kconfig
> @@ -90,6 +90,16 @@ config DRM_FSL_LDB
>  	help
>  	  Support for i.MX8MP DPI-to-LVDS on-SoC encoder.
>
> +config DRM_IMX9_PARALLEL_DISPLAY_FORMAT
> +	tristate "Support for i.MX93 parallel display format"
> +	depends on OF && MFD_SYSCON
> +	depends on ARCH_MXC || COMPILE_TEST
> +	select DRM_KMS_HELPER
> +	select DRM_PANEL_BRIDGE
> +	help
> +	  Support for internal parallel display format configuration
> +	  found on i.MX91 and i.MX93 processors.
> +
>  config DRM_ITE_IT6263
>  	tristate "ITE IT6263 LVDS/HDMI bridge"
>  	depends on OF
> diff --git a/drivers/gpu/drm/bridge/Makefile b/drivers/gpu/drm/bridge/Makefile
> index 97304b429a530..ee3406fed880f 100644
> --- a/drivers/gpu/drm/bridge/Makefile
> +++ b/drivers/gpu/drm/bridge/Makefile
> @@ -6,6 +6,7 @@ obj-$(CONFIG_DRM_CHRONTEL_CH7033) += chrontel-ch7033.o
>  obj-$(CONFIG_DRM_CROS_EC_ANX7688) += cros-ec-anx7688.o
>  obj-$(CONFIG_DRM_DISPLAY_CONNECTOR) += display-connector.o
>  obj-$(CONFIG_DRM_FSL_LDB) += fsl-ldb.o
> +obj-$(CONFIG_DRM_IMX9_PARALLEL_DISPLAY_FORMAT) += imx9-parallel-disp-fmt.o
>  obj-$(CONFIG_DRM_ITE_IT6263) += ite-it6263.o
>  obj-$(CONFIG_DRM_ITE_IT6505) += ite-it6505.o
>  obj-$(CONFIG_DRM_LONTIUM_LT8912B) += lontium-lt8912b.o
> diff --git a/drivers/gpu/drm/bridge/imx9-parallel-disp-fmt.c b/drivers/gpu/drm/bridge/imx9-parallel-disp-fmt.c
> new file mode 100644
> index 0000000000000..c37bdda53377c
> --- /dev/null
> +++ b/drivers/gpu/drm/bridge/imx9-parallel-disp-fmt.c
> @@ -0,0 +1,213 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +/*
> + * Copyright (C) 2022 NXP
> + * Copyright (c) 2026 TQ-Systems GmbH <linux@ew.tq-group.com>,
> + * D-82229 Seefeld, Germany.
> + * Author: Alexander Stein
> + */
> +
> +#include <linux/media-bus-format.h>
> +#include <linux/mfd/syscon.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/platform_device.h>
> +#include <linux/regmap.h>
> +#include <drm/drm_atomic_helper.h>
> +#include <drm/drm_bridge.h>
> +#include <drm/drm_of.h>
> +#include <drm/drm_panel.h>
> +
> +#define DISPLAY_MUX_CTRL		0x60

look like you have not use reg in dts and hardcode 0x60 here.

Frank

> +#define  PARALLEL_DISP_FORMAT		GENMASK(10, 8)
> +#define  FORMAT_RGB888_TO_RGB888	FIELD_PREP(PARALLEL_DISP_FORMAT, 0)
> +#define  FORMAT_RGB888_TO_RGB666	FIELD_PREP(PARALLEL_DISP_FORMAT, 1)
> +#define  FORMAT_RGB565_TO_RGB565	FIELD_PREP(PARALLEL_DISP_FORMAT, 2)
> +#define  FORMAT_RGB555_TO_RGB555	FIELD_PREP(PARALLEL_DISP_FORMAT, 3)
> +#define  FORMAT_YUV_TO_YCBCR24		FIELD_PREP(PARALLEL_DISP_FORMAT, 4)
> +#define  FORMAT_YUV_TO_YUV444		FIELD_PREP(PARALLEL_DISP_FORMAT, 5)
> +
> +struct imx9_pdf {
> +	struct device *dev;
> +	struct drm_bridge bridge;
> +	struct drm_bridge *panel_bridge;
> +	struct regmap *regmap;
> +};
> +
> +static inline struct imx9_pdf *to_imx9_pdf(struct drm_bridge *bridge)
> +{
> +	return container_of(bridge, struct imx9_pdf, bridge);
> +}
> +
> +static int imx9_pdf_attach(struct drm_bridge *bridge,
> +	enum drm_bridge_attach_flags flags)
> +{
> +	struct imx9_pdf *pdf = to_imx9_pdf(bridge);
> +
> +	return drm_bridge_attach(bridge->encoder, pdf->panel_bridge,
> +	       			 bridge, flags);
> +}
> +
> +static void imx9_pdf_atomic_enable(struct drm_bridge *bridge,
> +				   struct drm_bridge_state *old_bridge_state)
> +{
> +	struct imx9_pdf *pdf = to_imx9_pdf(bridge);
> +	struct drm_atomic_state *state = old_bridge_state->base.state;
> +	const struct drm_bridge_state *bridge_state;
> +	u32 format;
> +
> +	/* Get the bus format from the bridge state. */
> +	bridge_state = drm_atomic_get_new_bridge_state(state, bridge);
> +
> +	switch (bridge_state->output_bus_cfg.format) {
> +	case MEDIA_BUS_FMT_RGB565_1X16:
> +		format = FORMAT_RGB565_TO_RGB565;
> +		break;
> +	case MEDIA_BUS_FMT_RGB666_1X18:
> +		format = FORMAT_RGB888_TO_RGB666;
> +		break;
> +	case MEDIA_BUS_FMT_RGB888_1X24:
> +		format = FORMAT_RGB888_TO_RGB888;
> +		break;
> +	default:
> +		/*
> +		 * Some bridges still don't set the correct bus format.
> +		 * Just print a warning.
> +		 */
> +		dev_warn(pdf->dev,
> +			 "Unsupported bus format 0x%04x, please check output bridge driver\n",
> +			 bridge_state->output_bus_cfg.format);
> +		return;
> +	}
> +
> +	regmap_update_bits(pdf->regmap, DISPLAY_MUX_CTRL, PARALLEL_DISP_FORMAT,
> +			   format);
> +}
> +
> +#define MAX_INPUT_SEL_FORMATS 2
> +static u32 *
> +imx9_pdf_atomic_get_input_bus_fmts(struct drm_bridge *bridge,
> +				   struct drm_bridge_state *bridge_state,
> +				   struct drm_crtc_state *crtc_state,
> +				   struct drm_connector_state *conn_state,
> +				   u32 output_fmt,
> +				   unsigned int *num_input_fmts)
> +{
> +	u32 *input_fmts;
> +
> +	*num_input_fmts = 0;
> +
> +	input_fmts = kcalloc(MAX_INPUT_SEL_FORMATS, sizeof(*input_fmts),
> +			     GFP_KERNEL);
> +	if (!input_fmts)
> +		return NULL;
> +
> +	input_fmts[0] = MEDIA_BUS_FMT_RGB888_1X24;
> +	input_fmts[1] = MEDIA_BUS_FMT_RGB565_1X16;
> +	*num_input_fmts = MAX_INPUT_SEL_FORMATS;
> +
> +	return input_fmts;
> +}
> +
> +#define MAX_OUTPUT_SEL_FORMATS 3
> +static u32 *
> +imx9_pdf_atomic_get_output_bus_fmts(struct drm_bridge *bridge,
> +				    struct drm_bridge_state *bridge_state,
> +				    struct drm_crtc_state *crtc_state,
> +				    struct drm_connector_state *conn_state,
> +				    unsigned int *num_output_fmts)
> +{
> +	u32 *output_fmts;
> +
> +	*num_output_fmts = 0;
> +
> +	output_fmts = kcalloc(MAX_OUTPUT_SEL_FORMATS, sizeof(*output_fmts),
> +			     GFP_KERNEL);
> +	if (!output_fmts)
> +		return NULL;
> +
> +	output_fmts[0] = MEDIA_BUS_FMT_RGB565_1X16;
> +	output_fmts[1] = MEDIA_BUS_FMT_RGB666_1X18;
> +	output_fmts[2] = MEDIA_BUS_FMT_RGB888_1X24;
> +	*num_output_fmts = MAX_OUTPUT_SEL_FORMATS;
> +
> +	return output_fmts;
> +}
> +
> +static enum drm_mode_status
> +imx9_pdf_mode_valid(struct drm_bridge *bridge,
> +		   const struct drm_display_info *info,
> +		   const struct drm_display_mode *mode)
> +{
> +	if (mode->clock > 80000)
> +		return MODE_CLOCK_HIGH;
> +
> +	return MODE_OK;
> +}
> +
> +static const struct drm_bridge_funcs funcs = {
> +	.attach = imx9_pdf_attach,
> +	.atomic_enable = imx9_pdf_atomic_enable,
> +	.atomic_duplicate_state = drm_atomic_helper_bridge_duplicate_state,
> +	.atomic_destroy_state = drm_atomic_helper_bridge_destroy_state,
> +	.atomic_get_input_bus_fmts = imx9_pdf_atomic_get_input_bus_fmts,
> +	.atomic_get_output_bus_fmts = imx9_pdf_atomic_get_output_bus_fmts,
> +	.atomic_reset = drm_atomic_helper_bridge_reset,
> +	.mode_valid = imx9_pdf_mode_valid,
> +};
> +
> +static int imx9_pdf_probe(struct platform_device *pdev)
> +{
> +	struct device *dev = &pdev->dev;
> +	struct device_node *remote;
> +	struct drm_panel *panel;
> +	struct imx9_pdf *pdf;
> +
> +	pdf = devm_kzalloc(dev, sizeof(*pdf), GFP_KERNEL);
> +	if (!pdf)
> +		return -ENOMEM;
> +
> +	pdf->dev = &pdev->dev;
> +	pdf->bridge.funcs = &funcs;
> +	pdf->bridge.of_node = dev->of_node;
> +	pdf->bridge.type = DRM_MODE_CONNECTOR_DPI;
> +
> +	pdf->regmap = syscon_node_to_regmap(dev->of_node->parent);
> +	if (IS_ERR(pdf->regmap))
> +		return dev_err_probe(dev, PTR_ERR(pdf->regmap),
> +				     "failed to get regmap\n");
> +
> +	remote = of_graph_get_remote_node(dev->of_node, 1, 0);
> +	panel = of_drm_find_panel(remote);
> +	of_node_put(remote);
> +	if (IS_ERR(panel))
> +		return PTR_ERR(panel);
> +
> +	pdf->panel_bridge = devm_drm_panel_bridge_add(dev, panel);
> +	if (IS_ERR(pdf->panel_bridge))
> +		return PTR_ERR(pdf->panel_bridge);
> +
> +	platform_set_drvdata(pdev, pdf);
> +
> +	devm_drm_bridge_add(dev, &pdf->bridge);
> +
> +	return 0;
> +}
> +
> +static const struct of_device_id imx9_pdf_dt_ids[] = {
> +	{ .compatible = "fsl,imx9-parallel-display-format", },
> +	{ /* sentinel */ }
> +};
> +MODULE_DEVICE_TABLE(of, imx9_pdf_dt_ids);
> +
> +static struct platform_driver imx9_pdf_driver = {
> +	.probe		= imx9_pdf_probe,
> +	.driver		= {
> +		.name		= "imx9-parallel-display-format",
> +		.of_match_table	= imx9_pdf_dt_ids,
> +	},
> +};
> +module_platform_driver(imx9_pdf_driver);
> +
> +MODULE_AUTHOR("Alexander Stein <alexander.stein@ew.tq-group.com>");
> +MODULE_DESCRIPTION("i.MX91/i.MX93 parallel display format driver");
> +MODULE_LICENSE("GPL v2");
> --
> 2.34.1
>

Re: [PATCH 0/2] i.MX91/93 parallel display bridge

[Liu Ying]

On 02/11/2025, Alexander Stein wrote:
> Hi,

Hi Alexander,

> 
> i.MX91/93 support a parallel display interface. There is a single register
> for configuring the output format. There is not much documentation, but
> apparently this does some internal conversion.
> Add a bridge driver (similar to fsl-ldb.c) for connecting a bridge/panel
> to lcdif.
> I'm a bit unsure about the name. There is no dedicated IP, according to
> reference manual, just that single register. I would also agree
> to imx9-dpi or imx93-dpi.
> Note: It's only applicable to i.MX91/93, but not i.MX95!
> 
> Tested on TQMa9352 on MBa91xxCA
> 
> Best regards,
> Alexander
> 
> Alexander Stein (2):
>   dt-bindings: display: bridge: ldb: Implement simple Freescale
>     i.MX91/93 DPI bridge
>   drm: bridge: imx9-parallel-disp-fmt: add i.MX91/93 parallel display
>     bridge
> 
>  .../bridge/fsl,imx9-parallel-disp-fmt.yaml    |  78 +++++++
>  drivers/gpu/drm/bridge/Kconfig                |  10 +
>  drivers/gpu/drm/bridge/Makefile               |   1 +
>  .../gpu/drm/bridge/imx9-parallel-disp-fmt.c   | 213 ++++++++++++++++++
>  4 files changed, 302 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/display/bridge/fsl,imx9-parallel-disp-fmt.yaml
>  create mode 100644 drivers/gpu/drm/bridge/imx9-parallel-disp-fmt.c
> 

Thanks for your patch series.  However, I have already sent a patch series[1]
to add the i.MX93 parallel display format configuration support.  I may send
a new version to rename .remove_new to .remove in the bridge driver at least.

[1] https://patchwork.freedesktop.org/series/113457/

-- 
Regards,
Liu Ying