From: Liu Ying <victor.liu@nxp.com>

NXP i.MX93 mediamix blk-ctrl contains one DISPLAY_MUX register which
configures parallel display format by using the "PARALLEL_DISP_FORMAT"
field. Add a DRM bridge driver to support the display format configuration.

Signed-off-by: Liu Ying <victor.liu@nxp.com>
[m.felsch@pengutronix.de: port to v6.19-rc1]
[m.felsch@pengutronix.de: add review feedback (Alexander)]
[m.felsch@pengutronix.de: fix to short Kconfig description (checkpath)]
[m.felsch@pengutronix.de: use "GPL" instead of "GPL v2" (checkpatch)]
[m.felsch@pengutronix.de: add bus-width support]
Signed-off-by: Marco Felsch <m.felsch@pengutronix.de>
---
 drivers/gpu/drm/bridge/imx/Kconfig      |  11 ++
 drivers/gpu/drm/bridge/imx/Makefile     |   1 +
 drivers/gpu/drm/bridge/imx/imx93-pdfc.c | 221 ++++++++++++++++++++++++++++++++
 3 files changed, 233 insertions(+)

diff --git a/drivers/gpu/drm/bridge/imx/Kconfig b/drivers/gpu/drm/bridge/imx/Kconfig
index b9028a5e5a065c3237b404111d8df57e8e017f9d..181ee87bc0f9f65ee0b6e5edbb48ba808dfbb71f 100644
--- a/drivers/gpu/drm/bridge/imx/Kconfig
+++ b/drivers/gpu/drm/bridge/imx/Kconfig
@@ -99,4 +99,15 @@ config DRM_IMX93_MIPI_DSI
 	  Choose this to enable MIPI DSI controller found in Freescale i.MX93
 	  processor.
 
+config DRM_IMX93_PARALLEL_DISP_FMT_CONFIG
+	tristate "NXP i.MX91/i.MX93 parallel display format configuration"
+	depends on OF
+	select DRM_KMS_HELPER
+	help
+	  On i.MX93 and i.MX91 SoCs the parallel display format output is
+	  controlled via the MEDIAMIX BLK-CTRL DISPLAY_MUX.
+
+	  Say 'Y' or 'M' if you use the parallel display output path on a
+	  i.MX93 or i.MX91 SoC.
+
 endif # ARCH_MXC || COMPILE_TEST
diff --git a/drivers/gpu/drm/bridge/imx/Makefile b/drivers/gpu/drm/bridge/imx/Makefile
index 8d01fda25451aaa1bf51a068da18948094327116..0ee768b8298915d0f81cd0be4cd3a75d674d9976 100644
--- a/drivers/gpu/drm/bridge/imx/Makefile
+++ b/drivers/gpu/drm/bridge/imx/Makefile
@@ -9,3 +9,4 @@ obj-$(CONFIG_DRM_IMX8QXP_PIXEL_COMBINER) += imx8qxp-pixel-combiner.o
 obj-$(CONFIG_DRM_IMX8QXP_PIXEL_LINK) += imx8qxp-pixel-link.o
 obj-$(CONFIG_DRM_IMX8QXP_PIXEL_LINK_TO_DPI) += imx8qxp-pxl2dpi.o
 obj-$(CONFIG_DRM_IMX93_MIPI_DSI) += imx93-mipi-dsi.o
+obj-$(CONFIG_DRM_IMX93_PARALLEL_DISP_FMT_CONFIG) += imx93-pdfc.o
diff --git a/drivers/gpu/drm/bridge/imx/imx93-pdfc.c b/drivers/gpu/drm/bridge/imx/imx93-pdfc.c
new file mode 100644
index 0000000000000000000000000000000000000000..490eb3906201c8fa5d747846b75bfc8e1f5f9189
--- /dev/null
+++ b/drivers/gpu/drm/bridge/imx/imx93-pdfc.c
@@ -0,0 +1,221 @@
+// SPDX-License-Identifier: GPL-2.0+
+
+/*
+ * Copyright 2022-2025 NXP
+ */
+
+#include <linux/bitfield.h>
+#include <linux/bits.h>
+#include <linux/media-bus-format.h>
+#include <linux/mfd/syscon.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/of_graph.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+
+#include <drm/drm_atomic_state_helper.h>
+#include <drm/drm_bridge.h>
+
+#define IMX93_DISPLAY_MUX_REG		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)
+
+struct imx93_pdfc {
+	struct drm_bridge bridge;
+	struct drm_bridge *next_bridge;
+	struct device *dev;
+	struct regmap *regmap;
+	u32 phy_bus_width;
+};
+
+static int
+imx93_pdfc_bridge_attach(struct drm_bridge *bridge, struct drm_encoder *encoder,
+			 enum drm_bridge_attach_flags flags)
+{
+	struct imx93_pdfc *pdfc = bridge->driver_private;
+
+	return drm_bridge_attach(bridge->encoder, pdfc->next_bridge, bridge, flags);
+}
+
+static void imx93_pdfc_bridge_atomic_enable(struct drm_bridge *bridge,
+					    struct drm_atomic_state *state)
+{
+	struct imx93_pdfc *pdfc = bridge->driver_private;
+	const struct drm_bridge_state *bridge_state;
+	unsigned int mask = PARALLEL_DISP_FORMAT;
+	unsigned int val;
+
+	bridge_state = drm_atomic_get_new_bridge_state(state, bridge);
+
+	switch (bridge_state->output_bus_cfg.format) {
+	case MEDIA_BUS_FMT_RGB888_1X24:
+		val = FORMAT_RGB888_TO_RGB888;
+		if (pdfc->phy_bus_width == 18) {
+			/*
+			 * Can be valid if physical bus limitation exists,
+			 * therefore use dev_dbg().
+			 */
+			dev_dbg(pdfc->dev, "Truncate two LSBs from each color\n");
+			val = FORMAT_RGB888_TO_RGB666;
+		}
+		break;
+	case MEDIA_BUS_FMT_RGB666_1X18:
+		val = FORMAT_RGB888_TO_RGB666;
+		break;
+	case MEDIA_BUS_FMT_RGB565_1X16:
+		val = FORMAT_RGB565_TO_RGB565;
+		break;
+	}
+
+	regmap_update_bits(pdfc->regmap, IMX93_DISPLAY_MUX_REG, mask, val);
+}
+
+/* TODO: Add YUV formats */
+static const u32 imx93_pdfc_bus_output_fmts[] = {
+	MEDIA_BUS_FMT_RGB888_1X24,
+	MEDIA_BUS_FMT_RGB666_1X18,
+	MEDIA_BUS_FMT_RGB565_1X16,
+};
+
+static bool imx93_pdfc_bus_output_fmt_supported(const  u32 fmt)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(imx93_pdfc_bus_output_fmts); i++) {
+		if (imx93_pdfc_bus_output_fmts[i] == fmt)
+			return true;
+	}
+
+	return false;
+}
+
+static u32 *
+imx93_pdfc_bridge_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)
+{
+	struct imx93_pdfc *pdfc = bridge->driver_private;
+	u32 *input_fmts;
+
+	*num_input_fmts = 0;
+
+	input_fmts = kmalloc(sizeof(*input_fmts), GFP_KERNEL);
+	if (!input_fmts)
+		return NULL;
+
+	*num_input_fmts = 1;
+
+	if (!imx93_pdfc_bus_output_fmt_supported(output_fmt)) {
+		dev_dbg(pdfc->dev, "No valid output bus-fmt detected, fallback to MEDIA_BUS_FMT_RGB888_1X24\n");
+		input_fmts[0] = MEDIA_BUS_FMT_RGB888_1X24;
+		return input_fmts;
+	}
+
+	switch (output_fmt) {
+	case MEDIA_BUS_FMT_RGB888_1X24:
+	case MEDIA_BUS_FMT_RGB565_1X16:
+		input_fmts[0] = output_fmt;
+		break;
+	case MEDIA_BUS_FMT_RGB666_1X18:
+		input_fmts[0] = MEDIA_BUS_FMT_RGB888_1X24;
+		break;
+	}
+
+	return input_fmts;
+}
+
+static int imx93_pdfc_bridge_atomic_check(struct drm_bridge *bridge,
+					  struct drm_bridge_state *bridge_state,
+					  struct drm_crtc_state *crtc_state,
+					  struct drm_connector_state *conn_state)
+{
+	struct imx93_pdfc *pdfc = bridge->driver_private;
+	const u32 format = bridge_state->output_bus_cfg.format;
+
+	if (imx93_pdfc_bus_output_fmt_supported(format))
+		return 0;
+
+	dev_warn(pdfc->dev, "Unsupported output bus format: 0x%x\n", format);
+
+	return -EINVAL;
+}
+
+static const struct drm_bridge_funcs funcs = {
+	.attach			= imx93_pdfc_bridge_attach,
+	.atomic_enable		= imx93_pdfc_bridge_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	= imx93_pdfc_bridge_atomic_get_input_bus_fmts,
+	.atomic_check		= imx93_pdfc_bridge_atomic_check,
+	.atomic_reset		= drm_atomic_helper_bridge_reset,
+};
+
+static int imx93_pdfc_bridge_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct imx93_pdfc *pdfc;
+	struct device_node *ep;
+	int err;
+
+	pdfc = devm_drm_bridge_alloc(dev, struct imx93_pdfc, bridge, &funcs);
+	if (IS_ERR(pdfc))
+		return PTR_ERR(pdfc);
+
+	pdfc->regmap = syscon_node_to_regmap(dev->of_node->parent);
+	if (IS_ERR(pdfc->regmap))
+		return dev_err_probe(dev, PTR_ERR(pdfc->regmap),
+				     "failed to get regmap\n");
+
+	/* No limits per default */
+	pdfc->phy_bus_width = 24;
+
+	/* Get output ep (port1/endpoint) */
+	ep = of_graph_get_endpoint_by_regs(dev->of_node, 1, -1);
+	if (ep) {
+		err = of_property_read_u32(ep, "bus-width", &pdfc->phy_bus_width);
+		of_node_put(ep);
+
+		/* bus-width is optional but it must have valid data if present */
+		if (err && err != -EINVAL)
+			return dev_err_probe(dev, err,
+					     "failed to query bus-width\n");
+	}
+
+	pdfc->next_bridge = devm_drm_of_get_bridge(dev, dev->of_node, 1, 0);
+	if (IS_ERR(pdfc->next_bridge))
+		return dev_err_probe(dev, PTR_ERR(pdfc->next_bridge),
+				     "failed to get next bridge\n");
+
+	pdfc->dev = dev;
+	pdfc->bridge.driver_private = pdfc;
+	pdfc->bridge.of_node = dev->of_node;
+	pdfc->bridge.type = DRM_MODE_CONNECTOR_DPI;
+
+	return devm_drm_bridge_add(dev, &pdfc->bridge);
+}
+
+static const struct of_device_id imx93_pdfc_dt_ids[] = {
+	{ .compatible = "nxp,imx93-pdfc", },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, imx93_pdfc_dt_ids);
+
+static struct platform_driver imx93_pdfc_bridge_driver = {
+	.probe	= imx93_pdfc_bridge_probe,
+	.driver	= {
+		.of_match_table = imx93_pdfc_dt_ids,
+		.name = "imx93_pdfc",
+	},
+};
+module_platform_driver(imx93_pdfc_bridge_driver);
+
+MODULE_DESCRIPTION("NXP i.MX93 parallel display format configuration driver");
+MODULE_AUTHOR("Liu Ying <victor.liu@nxp.com>");
+MODULE_LICENSE("GPL");

-- 
2.47.3

Hello Marco, Liu,

On Tue Jan 13, 2026 at 8:07 PM CET, Marco Felsch wrote:
> From: Liu Ying <victor.liu@nxp.com>
>
> NXP i.MX93 mediamix blk-ctrl contains one DISPLAY_MUX register which
> configures parallel display format by using the "PARALLEL_DISP_FORMAT"
> field. Add a DRM bridge driver to support the display format configuration.
>
> Signed-off-by: Liu Ying <victor.liu@nxp.com>
> [m.felsch@pengutronix.de: port to v6.19-rc1]
> [m.felsch@pengutronix.de: add review feedback (Alexander)]
> [m.felsch@pengutronix.de: fix to short Kconfig description (checkpath)]
> [m.felsch@pengutronix.de: use "GPL" instead of "GPL v2" (checkpatch)]
> [m.felsch@pengutronix.de: add bus-width support]
> Signed-off-by: Marco Felsch <m.felsch@pengutronix.de>

I'm sorry to be reviewing at v8 only, I hadn't noticed this series before.

> ---
>  drivers/gpu/drm/bridge/imx/Kconfig      |  11 ++
>  drivers/gpu/drm/bridge/imx/Makefile     |   1 +
>  drivers/gpu/drm/bridge/imx/imx93-pdfc.c | 221 ++++++++++++++++++++++++++++++++
>  3 files changed, 233 insertions(+)
>
> diff --git a/drivers/gpu/drm/bridge/imx/Kconfig b/drivers/gpu/drm/bridge/imx/Kconfig
> index b9028a5e5a065c3237b404111d8df57e8e017f9d..181ee87bc0f9f65ee0b6e5edbb48ba808dfbb71f 100644
> --- a/drivers/gpu/drm/bridge/imx/Kconfig
> +++ b/drivers/gpu/drm/bridge/imx/Kconfig
> @@ -99,4 +99,15 @@ config DRM_IMX93_MIPI_DSI
>  	  Choose this to enable MIPI DSI controller found in Freescale i.MX93
>  	  processor.
>
> +config DRM_IMX93_PARALLEL_DISP_FMT_CONFIG
> +	tristate "NXP i.MX91/i.MX93 parallel display format configuration"

Minor nit: this is a driver for a device, so calling it "configuration"
seems weird. From the code it looks like a device converting the color
format, so what about "NXP i.MX91/i.MX93 parallel display format
converter"?

[...]

> +static int imx93_pdfc_bridge_probe(struct platform_device *pdev)
> +{
> +	struct device *dev = &pdev->dev;
> +	struct imx93_pdfc *pdfc;
> +	struct device_node *ep;
> +	int err;
> +
> +	pdfc = devm_drm_bridge_alloc(dev, struct imx93_pdfc, bridge, &funcs);
> +	if (IS_ERR(pdfc))
> +		return PTR_ERR(pdfc);
> +
> +	pdfc->regmap = syscon_node_to_regmap(dev->of_node->parent);
> +	if (IS_ERR(pdfc->regmap))
> +		return dev_err_probe(dev, PTR_ERR(pdfc->regmap),
> +				     "failed to get regmap\n");
> +
> +	/* No limits per default */
> +	pdfc->phy_bus_width = 24;
> +
> +	/* Get output ep (port1/endpoint) */
> +	ep = of_graph_get_endpoint_by_regs(dev->of_node, 1, -1);
> +	if (ep) {
> +		err = of_property_read_u32(ep, "bus-width", &pdfc->phy_bus_width);
> +		of_node_put(ep);
> +
> +		/* bus-width is optional but it must have valid data if present */
> +		if (err && err != -EINVAL)
> +			return dev_err_probe(dev, err,
> +					     "failed to query bus-width\n");
> +	}
> +
> +	pdfc->next_bridge = devm_drm_of_get_bridge(dev, dev->of_node, 1, 0);
> +	if (IS_ERR(pdfc->next_bridge))
> +		return dev_err_probe(dev, PTR_ERR(pdfc->next_bridge),
> +				     "failed to get next bridge\n");
> +
> +	pdfc->dev = dev;
> +	pdfc->bridge.driver_private = pdfc;

pdfc embeds the struct drm_bridge, which is the mandatory design since
devm_drm_bridge_alloc() got added, so driver_private shouldn't be needed
anymore. Most drivers have a bridge_to_foo() inline function using
component_of() to get the private struct from the drm_bridge pointer,
e.g. [0] and [1].

[0] https://elixir.bootlin.com/linux/v6.18.5/source/drivers/gpu/drm/bridge/simple-bridge.c#L39-L43
[1] https://elixir.bootlin.com/linux/v6.18.5/source/drivers/gpu/drm/bridge/ti-sn65dsi83.c#L287-L290

A short discussion took place a few months ago about driver_private, kind
of suggesting it might be removed after all drivers have switched to
devm_drm_bridge_alloc(). I think we should at least not introduce new users
of driver_private at least.

Best regards,
Luca

--
Luca Ceresoli, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com

Hi Luca,

On 26-01-14, Luca Ceresoli wrote:
> Hello Marco, Liu,
> 
> On Tue Jan 13, 2026 at 8:07 PM CET, Marco Felsch wrote:
> > From: Liu Ying <victor.liu@nxp.com>
> >
> > NXP i.MX93 mediamix blk-ctrl contains one DISPLAY_MUX register which
> > configures parallel display format by using the "PARALLEL_DISP_FORMAT"
> > field. Add a DRM bridge driver to support the display format configuration.
> >
> > Signed-off-by: Liu Ying <victor.liu@nxp.com>
> > [m.felsch@pengutronix.de: port to v6.19-rc1]
> > [m.felsch@pengutronix.de: add review feedback (Alexander)]
> > [m.felsch@pengutronix.de: fix to short Kconfig description (checkpath)]
> > [m.felsch@pengutronix.de: use "GPL" instead of "GPL v2" (checkpatch)]
> > [m.felsch@pengutronix.de: add bus-width support]
> > Signed-off-by: Marco Felsch <m.felsch@pengutronix.de>
> 
> I'm sorry to be reviewing at v8 only, I hadn't noticed this series before.
> 
> > ---
> >  drivers/gpu/drm/bridge/imx/Kconfig      |  11 ++
> >  drivers/gpu/drm/bridge/imx/Makefile     |   1 +
> >  drivers/gpu/drm/bridge/imx/imx93-pdfc.c | 221 ++++++++++++++++++++++++++++++++
> >  3 files changed, 233 insertions(+)
> >
> > diff --git a/drivers/gpu/drm/bridge/imx/Kconfig b/drivers/gpu/drm/bridge/imx/Kconfig
> > index b9028a5e5a065c3237b404111d8df57e8e017f9d..181ee87bc0f9f65ee0b6e5edbb48ba808dfbb71f 100644
> > --- a/drivers/gpu/drm/bridge/imx/Kconfig
> > +++ b/drivers/gpu/drm/bridge/imx/Kconfig
> > @@ -99,4 +99,15 @@ config DRM_IMX93_MIPI_DSI
> >  	  Choose this to enable MIPI DSI controller found in Freescale i.MX93
> >  	  processor.
> >
> > +config DRM_IMX93_PARALLEL_DISP_FMT_CONFIG
> > +	tristate "NXP i.MX91/i.MX93 parallel display format configuration"
> 
> Minor nit: this is a driver for a device, so calling it "configuration"
> seems weird. From the code it looks like a device converting the color
> format, so what about "NXP i.MX91/i.MX93 parallel display format
> converter"?

works for me.

> 
> [...]
> 
> > +static int imx93_pdfc_bridge_probe(struct platform_device *pdev)
> > +{
> > +	struct device *dev = &pdev->dev;
> > +	struct imx93_pdfc *pdfc;
> > +	struct device_node *ep;
> > +	int err;
> > +
> > +	pdfc = devm_drm_bridge_alloc(dev, struct imx93_pdfc, bridge, &funcs);
> > +	if (IS_ERR(pdfc))
> > +		return PTR_ERR(pdfc);
> > +
> > +	pdfc->regmap = syscon_node_to_regmap(dev->of_node->parent);
> > +	if (IS_ERR(pdfc->regmap))
> > +		return dev_err_probe(dev, PTR_ERR(pdfc->regmap),
> > +				     "failed to get regmap\n");
> > +
> > +	/* No limits per default */
> > +	pdfc->phy_bus_width = 24;
> > +
> > +	/* Get output ep (port1/endpoint) */
> > +	ep = of_graph_get_endpoint_by_regs(dev->of_node, 1, -1);
> > +	if (ep) {
> > +		err = of_property_read_u32(ep, "bus-width", &pdfc->phy_bus_width);
> > +		of_node_put(ep);
> > +
> > +		/* bus-width is optional but it must have valid data if present */
> > +		if (err && err != -EINVAL)
> > +			return dev_err_probe(dev, err,
> > +					     "failed to query bus-width\n");
> > +	}
> > +
> > +	pdfc->next_bridge = devm_drm_of_get_bridge(dev, dev->of_node, 1, 0);
> > +	if (IS_ERR(pdfc->next_bridge))
> > +		return dev_err_probe(dev, PTR_ERR(pdfc->next_bridge),
> > +				     "failed to get next bridge\n");
> > +
> > +	pdfc->dev = dev;
> > +	pdfc->bridge.driver_private = pdfc;
> 
> pdfc embeds the struct drm_bridge, which is the mandatory design since
> devm_drm_bridge_alloc() got added, so driver_private shouldn't be needed
> anymore. Most drivers have a bridge_to_foo() inline function using
> component_of() to get the private struct from the drm_bridge pointer,
> e.g. [0] and [1].
> 
> [0] https://elixir.bootlin.com/linux/v6.18.5/source/drivers/gpu/drm/bridge/simple-bridge.c#L39-L43
> [1] https://elixir.bootlin.com/linux/v6.18.5/source/drivers/gpu/drm/bridge/ti-sn65dsi83.c#L287-L290
> 
> A short discussion took place a few months ago about driver_private, kind
> of suggesting it might be removed after all drivers have switched to
> devm_drm_bridge_alloc(). I think we should at least not introduce new users
> of driver_private at least.

Sure, I wasn't aware that driver_private is going to be removed.

Regards,
  Marco

> 
> Best regards,
> Luca
> 
> --
> Luca Ceresoli, Bootlin
> Embedded Linux and Kernel engineering
> https://bootlin.com
> 

-- 
#gernperDu 
#CallMeByMyFirstName

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