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.

[[email protected]: port to v7.0-rc1]
[[email protected]: add review feedback (Alexander)]
[[email protected]: fix to short Kconfig description (checkpath)]
[[email protected]: use "GPL" instead of "GPL v2" (checkpatch)]
[[email protected]: add bus-width support]
[ Liu Ying: Port to drm-misc/drm-misc-next(v7.2-rc2 based) ]
[ Liu Ying: Add nxp,imx91-pdfc compatible string ]
[ Liu Ying: Call drm_bridge_get() for next_bridge ]
[ Liu Ying: Reject unsupported output bus fmt in .atomic_get_input_bus_fmts() ]

Reviewed-by: Luca Ceresoli <[email protected]>
Signed-off-by: Marco Felsch <[email protected]>
Signed-off-by: Liu Ying <[email protected]>
---
Hi,

I'm taking Marco Felsch's v11 work over and trying to add the imx93-pdfc.c
driver.

DT binding patch and DT patch in v11 have already landed, so only need
to send the driver patch out for review.
---
Changes in v13:
- Reject unsupported output bus fmt in .atomic_get_input_bus_fmts()  (Sashiko 
bot)
- Tweak commit message about change log
- Link to v12: 
https://patch.msgid.link/20260722-v6-18-topic-imx93-parallel-display-v12-1-a59dbb4db...@nxp.com

Changes in v12:
- Link to v11: 
https://lore.kernel.org/r/20260303-v6-18-topic-imx93-parallel-display-v11-0-1b03733c8...@pengutronix.de
- Rebase onto latest drm-misc/drm-misc-next
- Drop DT binding patch and DT patch because they have landed
- Add nxp,imx91-pdfc compatible string
- Call drm_bridge_get() for next_bridge
- Cc Marco

Changes in v11:
- Link to v10: 
https://lore.kernel.org/r/20260302-v6-18-topic-imx93-parallel-display-v10-0-634fe2778...@pengutronix.de
- Fix double space (Liu)
- Drop 'const' (Liu)
- Drop GFP_KERNEL from kmalloc_obj() (Liu)
- Add r-b (Luca)

Changes in v10:
- Link to v9: 
https://lore.kernel.org/r/20260115-v6-18-topic-imx93-parallel-display-v9-0-2c5051e4b...@pengutronix.de
- Add MEDIA_BUS_FMT_FIXED (Liu)
- Drop next_bridge from driver struct and use bridge.next_bridge (Liu)
- Drop linux/of_address.h include (Liu)
- imx93-pdfc: drop bridge.driver_private usage++ (Liu)
- Make use of kmalloc_obj() (Liu)

Changes in v9:
- Link to v8: 
https://lore.kernel.org/r/20260113-v6-18-topic-imx93-parallel-display-v8-0-4abccdc47...@pengutronix.de
- dt-bindings: drop unncessary changes (Frank)
- imx93-pdfc: drop bridge.driver_private usage (Luca)
- Kconfig: Adapt Kconfig symbol and prompt (Luca)

Changes in v8:
- Link to v7: 
https://lore.kernel.org/r/20251202-v6-18-topic-imx93-parallel-display-v7-0-2cce31d64...@pengutronix.de
- dt-bindings: add nxp,imx91-pdfc compatible (Liu)
- dt-bindings: use video-interfaces.yaml# (Liu)
- dt-bindings: s/data lanes/data lines/ (Liu)
- dt-bindings: drop 'reg' poperty
- dt-bindings: drop #address-cells, #size-cells
- imx93-pdfc: drop drm/drm_print.h include (Liu)
- imx93-pdfc: s/exist/exists/ (Liu)
- imx93-pdfc: drop MEDIA_BUS_FMT_FIXED from imx93_pdfc_bus_output_fmts
- imx93-pdfc: imx93_pdfc_bus_output_fmt_supported: make fmt const
- imx93-pdfc: Rework input-fmt selection to always fallback to a sane
              default.
- imx93-pdfc: imx93_pdfc_bridge_atomic_check: make use of
              imx93_pdfc_bus_output_fmt_supported()
- imx93-pdfc: drop 'reg' dt-property usage
- imx93-pdfc: imx93_pdfc_bridge_probe: pass -1 for endpoint reg value (Liu)

Changes in v7:
- Link to v6: 
https://lore.kernel.org/r/20251201-v6-18-topic-imx93-parallel-display-v6-0-7b056e1e5...@pengutronix.de
- Add missing bits.h and bitfield.h headers (lkp)

Changes in v6:
- Link to v5: 
https://lore.kernel.org/all/[email protected]/
- Add bus-width support
- rebase onto v6.18-rc1
- add review feedback (Alexander)
- driver license "GPL v2" -> "GPL" (checkpatch)
- make use of reg of-property
- fix to short Kconfig description (checkpath)
- add OF integration

To: Liu Ying <[email protected]>
To: Andrzej Hajda <[email protected]>
To: Neil Armstrong <[email protected]>
To: Robert Foss <[email protected]>
To: Laurent Pinchart <[email protected]>
To: Jonas Karlman <[email protected]>
To: Jernej Skrabec <[email protected]>
To: Luca Ceresoli <[email protected]>
To: Maarten Lankhorst <[email protected]>
To: Maxime Ripard <[email protected]>
To: Thomas Zimmermann <[email protected]>
To: David Airlie <[email protected]>
To: Simona Vetter <[email protected]>
To: Frank Li <[email protected]>
To: Sascha Hauer <[email protected]>
To: Pengutronix Kernel Team <[email protected]>
To: Fabio Estevam <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: Marco Felsch <[email protected]>
---
 drivers/gpu/drm/bridge/imx/Kconfig      |  11 ++
 drivers/gpu/drm/bridge/imx/Makefile     |   1 +
 drivers/gpu/drm/bridge/imx/imx93-pdfc.c | 222 ++++++++++++++++++++++++++++++++
 3 files changed, 234 insertions(+)

diff --git a/drivers/gpu/drm/bridge/imx/Kconfig 
b/drivers/gpu/drm/bridge/imx/Kconfig
index 005a745e5c47..49fcecfee38e 100644
--- a/drivers/gpu/drm/bridge/imx/Kconfig
+++ b/drivers/gpu/drm/bridge/imx/Kconfig
@@ -107,4 +107,15 @@ config DRM_IMX93_MIPI_DSI
          Choose this to enable MIPI DSI controller found in Freescale i.MX93
          processor.
 
+config DRM_IMX93_PARALLEL_DISP_FMT_CONVERTER
+       tristate "NXP i.MX91/i.MX93 parallel display format converter"
+       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 94ac8c40ebe9..99f28cd013ae 100644
--- a/drivers/gpu/drm/bridge/imx/Makefile
+++ b/drivers/gpu/drm/bridge/imx/Makefile
@@ -10,3 +10,4 @@ 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_CONVERTER) += 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 000000000000..2d6ca95ed554
--- /dev/null
+++ b/drivers/gpu/drm/bridge/imx/imx93-pdfc.c
@@ -0,0 +1,222 @@
+// 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_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 device *dev;
+       struct regmap *regmap;
+       u32 phy_bus_width;
+};
+
+static struct imx93_pdfc *bridge_to_imx93_pdfc(struct drm_bridge *bridge)
+{
+       return container_of(bridge, struct imx93_pdfc, bridge);
+}
+
+static int
+imx93_pdfc_bridge_attach(struct drm_bridge *bridge, struct drm_encoder 
*encoder,
+                        enum drm_bridge_attach_flags flags)
+{
+       return drm_bridge_attach(bridge->encoder, bridge->next_bridge, bridge, 
flags);
+}
+
+static void imx93_pdfc_bridge_atomic_enable(struct drm_bridge *bridge,
+                                           struct drm_atomic_commit *state)
+{
+       struct imx93_pdfc *pdfc = bridge_to_imx93_pdfc(bridge);
+       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:
+       case MEDIA_BUS_FMT_FIXED:
+               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_FIXED,
+       MEDIA_BUS_FMT_RGB888_1X24,
+       MEDIA_BUS_FMT_RGB666_1X18,
+       MEDIA_BUS_FMT_RGB565_1X16,
+};
+
+static bool imx93_pdfc_bus_output_fmt_supported(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)
+{
+       u32 *input_fmts;
+
+       *num_input_fmts = 0;
+
+       if (!imx93_pdfc_bus_output_fmt_supported(output_fmt))
+               return NULL;
+
+       input_fmts = kmalloc_obj(*input_fmts);
+       if (!input_fmts)
+               return NULL;
+
+       *num_input_fmts = 1;
+
+       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:
+       case MEDIA_BUS_FMT_FIXED:
+               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_to_imx93_pdfc(bridge);
+       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_create_state    = drm_atomic_helper_bridge_create_state,
+};
+
+static int imx93_pdfc_bridge_probe(struct platform_device *pdev)
+{
+       struct device *dev = &pdev->dev;
+       struct drm_bridge *next_bridge;
+       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");
+       }
+
+       next_bridge = devm_drm_of_get_bridge(dev, dev->of_node, 1, 0);
+       if (IS_ERR(next_bridge))
+               return dev_err_probe(dev, PTR_ERR(next_bridge),
+                                    "failed to get next bridge\n");
+       pdfc->dev = dev;
+       pdfc->bridge.of_node = dev->of_node;
+       pdfc->bridge.type = DRM_MODE_CONNECTOR_DPI;
+       pdfc->bridge.next_bridge = drm_bridge_get(next_bridge);
+
+       return devm_drm_bridge_add(dev, &pdfc->bridge);
+}
+
+static const struct of_device_id imx93_pdfc_dt_ids[] = {
+       { .compatible = "nxp,imx91-pdfc", },
+       { .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 <[email protected]>");
+MODULE_LICENSE("GPL");

---
base-commit: 9499d3bc41a2c4e6a1badfb55f943b9d0c34f034
change-id: 20251201-v6-18-topic-imx93-parallel-display-95f9234bf6cc

Best regards,
--  
Regards,
Liu Ying

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